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  • 1.
    Al Jawaheri, Raad
    et al.
    Halmstad University, School of Business, Engineering and Science.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Negative impact of lake liming programmes on the species richness of dragonflies (Odonata): a study from southern Sweden2017In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 788, no 1, p. 99-113Article in journal (Refereed)
    Abstract [en]

    Liming programmes aiming to restore fish populations are being implemented in many acidified aquatic systems in northern Europe. We studied Odonata communities in 47 forest lakes in SW Sweden, 13 that are currently being limed, and 8 that have previously been limed. Thirty-one species were recorded, with the highest mean number in untreated lakes, followed by previously treated lakes and currently treated lakes. Species communities differed between untreated and limed lakes, but only few rare species found in the untreated lakes were absent in the treated lakes. Likewise, species known to thrive in acid environments were either rare or showed no preferences. Comparing the number of records of odonate species within a large regional area to the proportion of lakes inhabited in our study, we found that seven of the most commonly observed species occurred less frequently in limed lakes than in the untreated ones, including two of the three most common taxa. Reduced species numbers in limed lakes might be due to conditions on other trophic levels, including fish predation. We argue that Odonata should be considered when developing new biological indices of water quality, although the causes of the observed occurrence patterns need to be studied further. © 2016 Springer International Publishing Switzerland

  • 2.
    Andersson, Emma
    Halmstad University.
    A study of how fragmentation affects distribution and diversity among Nymphalidae, Papilionidae and Pieridae (Lepidoptera): in native and exotic forest fragments in southern Brazil2015Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
  • 3.
    Andersson, Julia
    Halmstad University, School of Business, Engineering and Science.
    Does clearcutting as a method for forestry impact the aquatic life in lakes nearby?2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Clearcutting is the most common method for forestry in Sweden. However research shows that this type of intense management can have a negative impact on biological biodiversity as it interferes with an area’s natural characteristics. Previous studies have mainly focused on biological effects on land. In this study dragonflies were used as biological indicators to investigate the impact of clearcutting in aquatic environments. The result from this study indicate that the use of clearcutting as a method for forestry can, with a certain postponement in time, negatively affect the species diversity of Odonata, and thus also the aquatic biodiversity in lakes in the immediate surroundings of a clearcut area, although it is still unclear exactly how and by which mechanisms. It is also uncertain if the effects are only temporarily, or long-term. If Sweden is to reach the environmental goal of Flourishing Lakes and Streams, it is essential to adopt further safety measures when conducting clearcutting near waters to avoid negative impact on the aquatic biological diversity.

  • 4.
    Bartholdsson, David
    Halmstad University.
    Den invasiva vresrosens (Rosa rugosa) etablering samt återetablering i de sanddominerade miljöerna i Gullbranna/Tönnersa naturreservat2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Vresrosen, Rosa rugosa, är en kraftigt invasiv art med en oerhörd konkurrenskraft i sanddominerademiljöer såsom sanddyner och sandblottor. Ofta leder etableringen av R. rugosa i dessasanddominerade miljöer till total igenväxning av området med en starkt negativ påverkan på deninhemska floran och faunan. Då merparten av arterna i dessa habitat är beroende av den unika miljönsom den skiftande sanden skapar så innebär igenväxningen ett mycket stort hot. När området bindsupp till en mer stabil miljö utan det permanent tidiga successionsstadium som den vanligtvis befinnersig i så påverkar det även näringsmängden i sanden med ökade näringshalter samt att de varma, öppnamicrositesen försvinner tillsammans med sandens förmåga att röra sig. Eftersom många av deovanliga och hotade arterna kräver en väldigt specifik miljö så försvinner de ofta också närigenväxningen nått så här långt. Denna studie fokuserar på vresrosens etablering och påverkan isanddominerade miljöer. Studien går även in forskning kring samt hur man praktiskt bekämparväxten, då den hotar många ekologiskt viktiga områden. Dessutom hanterar rapporten mina egnaresultat efter inventeringar i Gullbranna/Tönnersa, ett område som historiskt sett varit mycket hårtpåverkat av vresrosen.

  • 5.
    Bergström, Jakob
    Halmstad University, School of Business, Engineering and Science.
    Vedlevande Coleoptera och Hemiptera förekomst på öar i Kolsnaren i sydvästra Södermanland2017Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    ABSTRACT

    Seven islands in the lake Kolsnaren have been investigated. I have inventoried saproxylic insects and investigated what characters on dead wood and characters at the islands that have affected species number of beetles (Coleoptera) and true bugs (Hemiptera). This study shows a relatively low number of species of beetles and true bugs but the study was too small to estimate a proper result. Probably there is many more species, especially more rare/threatened species. The characters vary between islands, but even the individual islands had different tree species, thickness, degradation stage and sun exposure of dead wood. Therefore there were favourable conditions for many different saproxylic species that have different demands of the habitat to find suitable substrate. The islands are partly isolated by water but no longer distances. With that in mind it was important that there is plenty of dead wood with varying characters around Kolsnaren so they get the opportunity to disperse and recolonise the islands when even the habitats are changing in time. The dead woods thickness and degradation stage was the characters with most impact of the number of species.

  • 6.
    Bonnot, N. C.
    et al.
    Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences, Riddarhyttan, 730 91, Sweden.
    Bergvall, U. A.
    Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences, Riddarhyttan, 730 91, Sweden.
    Jarnemo, Anders
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Kjellander, P.
    Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences, Riddarhyttan, 730 91, Sweden.
    Who’s afraid of the big bad wolf?: Variation in the stress response among personalities and populations in a large wild herbivore2018In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 188, no 1, p. 85-95Article in journal (Refereed)
    Abstract [en]

    Faced with rapid environmental changes, individuals may express different magnitude and plasticity in their response to a given stressor. However, little is known about the causes of variation in phenotypic plasticity of the stress response in wild populations. In the present study, we repeatedly captured individual roe deer (Capreolus capreolus) from two wild populations in Sweden exposed to differing levels of predation pressure and measured plasma concentrations of stress-induced cortisol and behavioral docility. While controlling for the marked effects of habituation, we found clear between-population differences in the stress-induced cortisol response. Roe deer living in the area that was recently recolonized by lynx (Lynx lynx) and wolves (Canis lupus) expressed cortisol levels that were around 30% higher than roe deer in the human-dominated landscape free of large carnivores. In addition, for the first time to our knowledge, we investigated the stress-induced cortisol response in free-ranging newborn fawns and found no evidence for hypo-responsiveness during early life in this species. Indeed, stress-induced cortisol levels were of similar magnitude and differed between populations to a similar extent in both neonates and adults. Finally, at an individual level, we found that both cortisol and docility levels were strongly repeatable, and weakly negatively inter-correlated, suggesting that individuals differed consistently in how they respond to a stressor, and supporting the existence of a stress-management syndrome in roe deer. © 2018, The Author(s).

  • 7.
    Brönmark, Christer
    et al.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Weisner, Stefan E. B.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Indirect effects of fish community structure on submerged vegetation in shallow, eutrophic lakes: an alternative mechanism1992In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 243/244, no 1, p. 293-301Article in journal (Refereed)
    Abstract [en]

    The loss of submerged macrophytes during eutrophication of shallow takes is a commonly observed phenomenon. The proximate reason for this decline is a reduction of available light due to increasing phytoplankton and/or epiphyton biomass. Here we argue that the ultimate cause for the transition from a macrophyte-dominated state to a phytoplankton-dominated state is a change in fish community structure. A catastrophic disturbance event (e.g. winterkill) acting selectively on piscivores, cascades down food chains, eventually reducing macrophyte growth through shading by epiphyton, an effect that is reinforced by increasing phytoplankton biomass. The transition back from the phytoplankton to the macrophyte state depends on an increase in piscivore standing stock and a reduction of planktivores. A conceptual model of these mechanisms is presented and supported by literature data and preliminary observations from a field experiment. © 1992 Kluwer Academic Publishers.

  • 8.
    Brönmark, Christer
    et al.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Weisner, Stefan E.B.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Decoupling of cascading trophic interactions in a freshwater, benthic food chain1996In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 108, no 3, p. 534-541Article in journal (Refereed)
    Abstract [en]

    Food chain theory provides explicit predictions for equilibrium biomasses among trophic levels in food chains of different lengths. Empirical studies on freshwater benthic food chains have typically been performed on chains with up to three levels and in field experiments with limited spatial and temporal scale. Here we use a ‘’natural snapshot experiment” approach to study equilibrium biomass and abundance among trophic levels in natural ponds differing only with respect to fish assemblage structure. Forty-four ponds were surveyed for their density and biomass of fish, snails and periphyton. Ponds were divided into three categories based on fish assemblage: ponds with no fish (two trophic levels), ponds with molluscivorous fish (three trophic levels), ponds with molluscivorous fish (three trophic levels) and ponds that also had piscivorous fish (four trophic levels). Ponds without fish had a high density and biomass of snails and a low biomass of periphyton, whereas snails with molluscivorous fish. In the presence of piscivores, molluscivore populations consisted of low numbers of large individuals. Snail assemblages in piscivore ponds were characterised by relatively high densities of small-bodied detritivorous species and periphyton biomass was not significantly different from ponds with three trophic levels. Thus, predictions from classic food chain theory were upheld in ponds with up to three trophic levels. In ponds with four trophic levels, however, there was a decoupling of the trophic cascade at the piscivore-molluscivore level. Gape-limited piscivory, predation on snails by molluscivores that have reached an absolute size refuge from predation, and changes in food preferences of the dominant snails are suggested to explain the observed patterns.

  • 9.
    Carlzon, Linnéa
    et al.
    Halmstad University, School of Business, Engineering and Science.
    Karlsson, Amanda
    Halmstad University, School of Business, Engineering and Science.
    Falk, Knud
    www.vandrefalk.dk, Stockholm, Sweden.
    Liess, Antonia
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Møller, Søren
    Roskilde University Library, Roskilde, Denmark.
    Extreme weather affects Peregrine Falcon (Falco peregrinus tundrius) breeding success in South Greenland2018In: Ornis Hungarica, ISSN 1215-1610, Vol. 26, no 2, p. 38-50Article in journal (Refereed)
    Abstract [en]

    In order to better understand the potential effects of climate change on the Peregrine Falcon, we investigated the relationship between extreme weather events and Peregrines’ breeding success in South Greenland. We defined three variables – number of days with extremely low temperatures, extreme precipitation, consecutive rainy days – and an additive variable, total days with extreme weather, and tested their relationship with Peregrines’ breeding success (measured as young per site and nest success) over a 33 year study period. Breeding success was negatively influenced by the number of days with extreme weather and extremely low temperature. The strongest relationship found was total days with extreme weather in the entire breeding season, which explained 22% and 27% of the variation in nest success and young per site, respectively. The number of days with extreme weather in our study related to fluctuations in the North Atlantic Oscillation (NAO). Thus, with a strengthening of the NAO, linked to climate change, more extreme weather may occur in the Arctic and induce increased variation in Peregrines’ breeding success. Our data did not allow us to pinpoint when in the breeding cycle inclement weather was particularly harmful, and we recommend finer-scale research (e.g. automated nest cameras) to better monitor the species-specific effects of rapidly changing climate.

  • 10.
    David, M.
    et al.
    Inst. National de la Recherche Agronomique, UMR Environnement et Grandes Cultures, Thiverval-Grignon, France.
    Loubet, B.
    Inst. National de la Recherche Agronomique, UMR Environnement et Grandes Cultures, Thiverval-Grignon, France.
    Cellier, P.
    Inst. National de la Recherche Agronomique, UMR Environnement et Grandes Cultures, Thiverval-Grignon, France.
    Mattsson, Marie
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS).
    Schjoerring, J.K.
    Plant and Soil Science Laboratory, University of Copenhagen, Faculty of Life Sciences, Copenhagen, Denmark.
    Nemitz, E.
    Centre for Ecology and Hydrology (Edinburgh Research Station), Bush Estate, Penicuik, Midlothian ,UK.
    Roche, R.
    Inst. National de la Recherche Agronomique, UMR Environnement et Grandes Cultures.
    Riedo, M.
    Inst. fur Agrarokologie, Bundesforschungsanstalt fur Landwirtschaft (FAL), Braunschweig, Germany.
    Sutton, M.A.
    Centre for Ecology and Hydrology (Edinburgh Research Station), Bush Estate, Penicuik, Midlothian ,UK.
    Ammonia sources and sinks in an intensively managed grassland canopy2009In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 6, no 9, p. 1903-1915Article in journal (Refereed)
    Abstract [en]

    Grasslands represent canopies with a complex structure where sources and sinks of ammonia (NH3) may coexist at the plant level. Moreover, management practices such as mowing, hay production and grazing may change the composition of the sward and hence the source-sink relationship at the canopy level as well as the interaction with the atmosphere. There is therefore a need to understand the exchange of ammonia between grasslands and the atmosphere better, especially regarding the location and magnitude of sources and sinks. Fluxes of atmospheric NH3 within a grassland canopy were assessed in the field and under controlled conditions using a dynamic chamber technique (cuvette). These cuvette measurements were combined with extraction techniques to estimate the ammonium (NH+4 ) concentration and the pH of a given part of the plant or soil, leading to an estimated ammo- nia compensation point (Cp ). The combination of the cuvette and the extraction techniques was used to identify the poten- tial sources and sinks of NH3 within the different compart- ments of the grassland: the soil, the litter or senescent “litter leaves”, and the functioning “green leaves”. A set of six field experiments and six laboratory experiments were performed in which the different compartments were either added or removed from the cuvettes.The results show that the cuvette measurements agree with the extraction technique in ranking the strength of compartment sources. It suggests that in the studied grassland the green leaves were mostly a sink for NH3 with a compensation point around 0.1–0.4 μg m−3 and   an NH3 flux of 6 to 7 ng m−2 s−1. Cutting of the grass did not increase the NH3 fluxes of the green leaves. The litter was found to be the largest source of NH3 in the canopy, with a Cp of up to 1000μgm−3 NH3 andanNH3 fluxupto90ngm−2 s−1. The litter was found to be a much smaller NH3 source when dried (Cp =160 μg m−3 and FNH3 =35 ng m−2 s−1 NH3 ). Moreover emissions from the litter were found to vary with the relative humidity of the air. The soil was a strong source of NH3 in the period immediately after cutting (Cp =320 μg m−3 and FNH3 =60 ng m−2 s−1 ), which was nevertheless always smaller than the litter source. The soil NH3 emissions lasted, however, for less than one day, and were not observed with sieved soil. They could not be solely explained by xylem sap flow extruding NH+4 . These results indicate that future research on grassland-ammonia relationships should focus on the post-mowing period and the role of litter in interaction with meteorological conditions.

  • 11.
    Eriksson, Peder G
    et al.
    Limnology, Department of Ecology, Lund University, Lund, Sweden .
    Weisner, Stefan E.B.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    An experimental study on effects of submersed macrophytes on nitrification and denitrification in ammonium-rich aquatic systems1999In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 44, no 8, p. 1993-1999Article in journal (Refereed)
    Abstract [en]

    We have examined the role of microbial communities on the surface of submersed macrophytes and in the underlying sediment for nitrification and denitrification in light and dark in NH(4)(+)-enriched microcosm systems using isotope pairing and dilution techniques. Potamogeton pectinatus L. and intact sediment cores were collected in a shallow reservoir receiving treated municipal wastewater and containing dense submersed vegetation. Chambers containing P. pectinatus shoots, sediment, or both P. pectinatus shoots and sediment were exposed to 6 h of darkness, 6 h of light, and 6 h of darkness. (14)NH(4)(+) and (15)NO(3)(-) were added at ambient concentrations of 15 and 5 mg N liter(-1), respectively. NH(4)(+) was primarily nitrified in the epiphytic microbial communities, and NO; was denitrified in the underlying sediment. In chambers containing macrophytes, there was a net production of O(2) and NO(3)(-) in light and a net consumption in dark, and nitrification was higher in light than in dark. In chambers with only sediment, there was always a net consumption of NO(3)(-), and nitrification was similar in light and dark. The results show that submersed macrophytes can be important for the N metabolism in NH(4)(+)-rich freshwaters (e.g., wastewater treatment systems) by stimulating nitrification through providing surfaces for attached nitrifying bacteria and possibly also through diurnal changes in the water chemistry.

  • 12.
    Eriksson, Peder G.
    et al.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Weisner, Stefan E.B.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Functional differences in epiphytic microbial communities in nutrient-rich freshwater ecosystems: An assay of denitrifying capacity1996In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 36, no 3, p. 555-562Article in journal (Refereed)
    Abstract [en]

    1. The denitrifying capacity of epiphyton was used to evaluate differences in the function of epiphytic microbial communities on submersed macrophytes in nutrient-rich freshwater ecosystems. The denitrifying capacity of epiphyton on Patamogeton perfoliatus shoots of different age and with different epiphytic abundances from a eutrophic lake was investigated in laboratory microcosms in the Light and dark. Additionally, differences between epiphyton on shoots of Potamogeton pectinatus grown under different in Situ nutrient and hydraulic conditions were investigated by examining their denitrifying capacity. 2. Denitrification was registered in well-developed epiphytic layers on both mature and senescent shoots in the dark, with activities 3- to 10-fold higher in the epiphytic communities of senescent shoots. No activity was detected on young shoots with sparse epiphyton or on shoots from which loosely attached epiphyton had been removed. Denitrification never occurred during illumination. 3. Even though the epiphytic abundance was similar in magnitude, the denitrifying capacity of epiphyton adapted to high nutrient loadings was about a hundred times higher than that of epiphyton adapted to lower nutrient levels. Additionally, epiphytic abundance and denitrifying capacity were higher at sites less exposed to wave turbulence or water currents, than at sites with more water turbulence. 4. The results illustrate how the hydraulic and nutrient conditions of the surrounding water affect both the quantity and function of epiphytic microbial communities in nutrient-rich freshwater ecosystems.

  • 13.
    Eriksson, Peder G.
    et al.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Weisner, Stefan E.B.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Nitrogen removal in a wastewater reservoir: The importance of denitrification by epiphytic biofilms on submersed vegetation1997In: Journal of Environmental Quality, ISSN 0047-2425, E-ISSN 1537-2537, Vol. 26, no 3, p. 905-910Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to examine the importance of epiphytic denitrifying bacteria on submersed vegetation in removing N from a shallow nutrient-enriched freshwater ecosystem. The investigation was conducted during the summer of 1994 in a surface now reservoir receiving municipal tertiary-treated wastewater. The submersed vegetation in the reservoir was dominated by Potamogeton pectinatus L. and filamentous green algae (FGA). The N loading was 2300 mg N h(-1) m(-2) and the N removal, calculated as the mean difference between influent and effluent N, was 190 mg N h(-1) m(-2) (8%). The majority of influent N consisted of NH4+, but the main part of the N removal was due to the removal of NO3- whereas no net retention of NH4+ was found. Mean total soluble solids and BOD7 retention was 69 and 38%, respectively, Denitrification measurements were conducted in darkness at in situ temperature in microcosms with P. pectinatus, FGA, or infect sediment cores. Epiphytic denitrification ranged between 0.21 to 7.0 mg N h(-1) m(-2) reservoir surface area depending on the abundance of the submersed vegetation (5-140 g DW m(-2)). Sediment denitrification was 4.7 mg N h(-1) m-L reservoir surface area. The mean assimilative N uptake of the submersed vegetation and epiphyton was 3.4 and 1.6 mg N h(-1) m(-2) reservoir surface area, respectively. Measured N removal rates through plant uptake and denitrification could only account for a minor part of the N removal observed by mass balance. However, microcosm denitrification measurements underestimate actual denitrification. Thus, the major part of the N removal was most likely due to denitrification. In conclusion, this study indicates that denitrification in epiphytic microbial communities on submersed vegetation can be of significant importance for the N removal in nutrient-enriched freshwater ecosystems.

  • 14. Eriksson, P.G.
    et al.
    Svensson, J.M.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Wetland Research Centre.
    Carrer, M.
    Dipto. Proc. Chimici dell'Ingegneria, Université di Padova, Padua, Italy.
    Temporal changes and spatial variation of soil oxygen consumption, nitrification and denitrification rates in a tidal salt marsh of the Lagoon of Venice, Italy2003In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 58, no 4, p. 861-871Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to investigate seasonal and spatial patterns of soil oxygen consumption, nitrification, denitrification and fluxes of dissolved inorganic nitrogen (DIN) in a tidal salt marsh of the Lagoon of Venice, Italy. In the salt marsh, intact soil cores including overlying water were collected monthly at high tide from April to October in salt marsh creeks and in areas covered by the dominant vegetation, Limonium serotinum. In May, cores were also collected in areas with vegetation dominated by Juncus maritimus and Halimione portulacoides. In laboratory incubations at in situ temperature in the dark, flux rates of oxygen and DIN were monitored in the overlying water of the intact cores. 15N-nitrate was added to the overlying water and nitrification and denitrification were measured using isotope-dilution and -pairing techniques. The results show that highest soil oxygen consumption coincided with the highest water temperature in June and July. The highest denitrification rates were recorded in spring and autumn coinciding with the highest nitrate concentrations. Soil oxygen consumption and nitrification rates differed between sampling sites, but denitrification rates were similar among the different vegetation types. The highest rates were recorded in areas covered with L. serotinum. Burrowing soil macrofauna enhanced oxygen consumption, nitrification and denitrification in April and May. The data presented in this study indicate high temporal as well as spatial variations in the flux of oxygen and DIN, and nitrogen transformations in the tidal salt marshes of the Venice lagoon during the growth season. The results identify the salt marshes of the Venice lagoon as being metabolically very active ecosystems with a high capacity to process nitrogen.

  • 15.
    Graneli, Wilhelm
    et al.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Weisner, Stefan E.B.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Sytsma, Mark D.
    UC Davis, Department of Botany, Davis, United States.
    Rhizome dynamics and resource storage in Phragmites australis1992In: Wetlands Ecology and Management, ISSN 0923-4861, E-ISSN 1572-9834, Vol. 1, no 4, p. 239-247Article in journal (Refereed)
    Abstract [en]

    Seasonal changes in rhizome concentrations of total nonstructural carbohydrates (TNC), water soluble carbohydrates (WSC), and mineral nutrients (N, P and K) were monitored in two Phragmites australis stands in southern Sweden. Rhizome biomass, rhizome length per unit ground area, and specific weight (weight/ length ratio) of the rhizomes were monitored in one of the stands. Rhizome biomass decreased during spring, increased during summer and decreased during winter. However, changes in spring and summer were small (< 500 g DW m-2) compared to the mean rhizome biomass (approximately 3000 g DW m-2). Winter losses were larger, approximately 1000 g DW m-2, and to a substantial extent involved structural biomass, indicating rhizome mortality. Seasonal changes in rhizome length per unit ground area revealed a rhizome mortality of about 30% during the winter period, and also indicated that an intensive period of formation of new rhizomes occurred in June. Rhizome concentrations of TNC and WSC decreased during the spring, when carbohydrates were translocated to support shoot growth. However, rhizome standing stock of TNC remained large (> 1000 g m-2). Concentrations and standing stocks of mineral nutrients decreased during spring/ early summer and increased during summer/ fall. Only N, however, showed a pattern consistent with a spring depletion caused by translocation to shoots. This pattern indicates sufficient root uptake of P and K to support spring growth, and supports other evidence that N is generally the limiting mineral nutrient for Phragmites. The biomass data, as well as increased rhizome specific weight and TNC concentrations, clearly suggests that "reloading" of rhizomes with energy reserves starts in June, not towards the end of the growing season as has been suggested previously. This resource allocation strategy of Phragmites has consequences for vegetation management. Our data indicate that carbohydrate reserves are much larger than needed to support spring growth. We propose that large stores are needed to ensure establishment of spring shoots when deep water or stochastic environmental events, such as high rhizome mortality in winter or loss of spring shoots due to late season frost, increase the demand for reserves. © 1992 SPB Academic Publishing.

  • 16.
    Hansson, Jessica
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Ecology and Environmental Science.
    Does the wolf (Canis lupus) affect presence of the red fox (Vulpes vulpes) in Sweden?2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Vargen (Canis lupus) har ökat stadigt i Sverige under de senaste decennierna. Vargens återkomst och dess påverkan på det svenska djurlivet studeras idag i stor utsträckning, och frågor har uppstått om vargen som toppredator kan komma att orsaka trofiska kaskader i ekosystemet, vilket har observerats i nationalparker i USA. Rödräven (Vulpes vulpes) har i Sverige visat sig dra stor nytta utav vargens återkomst genom den ökade mängden kadaver som vargen lämnar, vilket är en särskilt viktig födokälla under våren.

    Syftet med denna studie var att undersöka om närvaro av varg påverkar förekomst av rödräv. Rävspår räknades i 182 vilttrianglar i Örebro och Värmlands län under åren 2001-2003. Vilttrianglarna klassificerades med avseende på mängd jordbruksmark, avstånd till vargrevir och ålder på vargrevir. Effekt av varg på rävförekomst analyserades genom att jämföra rävspår med distans till vargrevir och hur länge det funnits varg i området samt rävspår i relation till mängd jordbruksmark. Studien kunde inte påvisa någon effekt av vargförekomst på räv.  Resultaten indikerar på att habitatet var nyckelfaktorn för rävförekomst istället för närvaro av varg. I och med att vargstammen ökar stadigt i Sverige är det dock av intresse med fortsatta studier i ämnet då vargen kan komma att spela en större roll i ekosystemet i framtiden.

  • 17.
    Hedström, Ingemar
    et al.
    Boston University, College of Arts and Sciences, Boston, MA, United States.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    An extended description of the larva of Megaloprepus caerulatus from Costa Rica (Odonata: Pseudostigmatidae)2003In: International Journal of Odonatology, ISSN 1388-7890, Vol. 6, no 1, p. 23-31Article in journal (Refereed)
    Abstract [en]

    The larva of Megaloprepus caerulatus is described and illustrated from specimens collected near the northern border of Barbilla National Park on the Costa Rican Caribbean slope. Habits and characters of larvae of three different size classes obtained from artificial tree holes permit the identification of small (body length 4 mm, excluding the caudal lamellae) larvae up to the final stadium. New diagnostic characters include the shape of the prementum and head. © 2003 Taylor & Francis Group, LLC.

  • 18.
    Ivarsson, Sofia
    Halmstad University, School of Business, Engineering and Science.
    Invertebrate colonisation and diversity in constructed wetlands in Halland: A comparison between 2004 and 20062017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 19.
    Jaggwe, Assad
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS).
    Effects of Environmental Variables on Four Aquatic Insect Taxa among Smaller Water Bodies of Different Ages on Farmland; A Pilot Study2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    High anthropogenic modification like infrastructural development, drainage, eutrophication, dumping garbage, is a threat to biodiversity of smaller water bodies in agricultural landscapes. However, smaller water bodies have historically been constructed for drainage, waste treatment and other purposes. Further, new small water bodies are now being constructed in agricultural areas in Sweden, mainly to remove nutrients and to improve landscape biodiversity. This creates two different age classes (old and new) of smaller water body habitats. I sampled aquatic insects in 27 smaller water bodies of varying types and ages in Halmstad region and related insect biodiversity, species richness, composition structure to environmental variables. I partitioned the region into two locations (Northern and Southern) for easy data comparison and due to difference in topography. The data was analysed using a Canonical Correspondence (CCA) and regression analysis. The CCA results show a difference in the species composition between old and new sites. The most important variables in explaining species assemblage structure was age of the aquatic water bodies. The species richness decreased with increase in nutrient concentration (total phosphorus) according to regression analysis. Species composition and diversity were related to Vegetation and tree cover in and around the water body. The results of my study shows that the older the water bodies the better for specific species like Aeshna cyanea and the new water bodies tolerate more specimens. My results suggest that, as there is need to facilitate plant growing, protecting vegetation and trees to better mimic natural conditions of water bodies, creating new water bodies while protecting aged water bodies is important for conservation of biodiversity.

  • 20.
    Jarnemo, Anders
    et al.
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS). Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences, SE-730 91 Riddarhyttan, Sweden.
    Minderman, Jeroen
    Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, United Kingdom.
    Bunnefeld, Nils
    Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, United Kingdom.
    Zidar, Josefina
    Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden.
    Månsson, Johan
    Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences, SE-730 91 Riddarhyttan, Sweden.
    Managing landscapes for multiple objectives: Alternative forage can reduce the conflict between deer and forestry2014In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 5, no 8Article in journal (Refereed)
    Abstract [en]

    Deer (Cervidae) cause considerable damage to forest plantations, crops, and protected habitats. The most common response to this damage is to implement strategies to lower population densities. However, lowering deer density may not always be desirable from hunting, recreational, or conservation perspectives. Therefore, knowledge is needed about additional factors beyond deer density that affect damage levels, and management actions that consider competing management goals. We studied the relationships between levels of bark-stripping by red deer (Cervus elaphus) on Norway spruce (Picea abies) and (1) relative deer density indices (pellet group count and deer harvest data), (2) availability of alternative natural forage (cover of forage species) and (3) proportion forest in the landscape, both at a forest stand scale and at a landscape scale. Extensive variation in damage level was evident between the six study areas. On a stand scale, the proportion of spruce damaged was positively related to pellet group density, indicating the importance of local deer usage of stands. In addition, available alternative forage in the field layer within spruce stands and proportion forest surrounding stands was negatively related to damage level. On the landscape scale, damage level was negatively related to availability of forage in the field and shrub layers and proportion forest, but was not related to any of the relative deer density indices. Increasing alternative forage may thus decrease damage and thereby reduce conflicts. Additionally, the proportion of forest in the landscape affects damage levels and should thus be considered in landscape planning and when forecasting damage risk. The relationship between local deer usage of stands and damage level suggests that future studies should try to separate the effects of local deer usage and deer density. © 2014 Jarnemo et al.

  • 21.
    Johannesson, Malin
    Halmstad University, School of Business and Engineering (SET).
    Prey choice of the snow leopard (Panthera uncia) in the Gobi desert in southern Mongolia.2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To properly plan a conservation strategy for large, elusive carnivores that lives in remote areas, there is a need for correct information about their diet. Problematically, endangered species such as the snow leopard are difficult to obtain information on, due to their camouflage, secretiveness and isolated lives in rugged ecosystems. Global positioning system (GPS) collars can thus provide useful information on snow leopard ecology and behavior. This study took place in the Gobi desert in southern Mongolia, and aimed to investigate the prey choices of the snow leopard. In total there were 19 snow leopards captured between 2008 and 2013 that were fitted with GPS collars. These collars registered a position every fifth to seventh hour. Kill sites were found by visiting clusters of GPS locations. Ibex was the prey most dominated (66 %), followed by goat, sheep (20 %), and argali (8 %). The ibex and argali were sex- and age-classified.  Age and sex ratio of the killed ibex differed from the age and sex ratio of the ibex population. Adult ibex males seemed to be overrepresented among the kills (males <5 years 10 % and males >5 years 35 %), whereas females seemed underrepresented. Also in argali, the category most killed were males (56 %). The results show that snow leopards do not only kill prey larger than themselves, they also seem to select the largest age and sex categories among ibex and argali, although the different categories killed varied between seasons. Possible explanations for the results are discussed. The findings of this study will help to understand the feeding ecology of the snow leopard, and how to address the conservation and management issues in how to conserve this felid and its most important preys.

  • 22.
    Johansson, Alfred
    Halmstad University, School of Business, Engineering and Science.
    Hållbar vattenkraft i Nissan: En förstudie och konsekvensutredning över förutsättningarna för ökade vandringsmöjligheter med nya fiskvägar.2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The hydropower from Nissan River is of national interest and produces annually 230 GWh from the twelve power stations in the main flow. For modified waters a consideration between the power production and the biological values has to be made. This reports serves as a pre-study for Nissans Vattenråd. It tries to evaluate some of the biological values in the Nissan basin and map the power production in the area. And the size and value of lost power production from new fishways for the twelve stations in the main flow.

    The investment of new fishways is calculated using simplified templates with values from the business. The cost and loss of power due to new fishways are calculated for three cases: fish friendly grates for the power station inlet and bypass for migration. Fish friendly grate and vertical-slot fish passage for migration. The last case is called “scenario” and is a combination with the most suited solution for each station. This includes a restoration of the creek, with maintained power production, for the two stations closest to the ocean.

    The cost for fish friendly grade and bypass for al stations is about 207 mskr and for vertical-slot fish passage 125 mskr. They both result in a loss of power production of 12 GWh/year, corresponding to a value of 3,2 mskr (NordSpot sale price only) annually. Case “scenario” costs 177 mskr and loses additionally 4,2 GWh/year.

    In the overview, large parts of the Nissan runoff has difficulties reaching “god ecological status” which is the goal set for 2021. This goal can be extended to 2027. The main problem is chemical effect of acidification and mercury in the ground, as well as connectivity issue caused by dams and culverts. Salmon and sea trout could earlier migrate to Nissafors and is limited to the lower parts of Nissan to Oskarström. Many of the tributary waters have high biological values. The existing fishways have questioned functionality and delays fish migration today. Before decisions are made about increasing fishways the advice is to do further studies about the breeding grounds. It’s also possible to identify positive cash flows from an increase in fish migration.

  • 23.
    Koch, Kamilla
    et al.
    Department of Ecology, Johannes Gutenberg-University of Mainz, Mainz, Germany.
    Wagner, Christine
    Department of Ecology, Johannes Gutenberg-University of Mainz, Mainz, Germany.
    Sahlén, Göran
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS).
    Farmland versus forest: comparing changes in Odonata species composition in western and eastern Sweden2014In: Insect Conservation and Diversity, ISSN 1752-458X, E-ISSN 1752-4598, Vol. 7, no 1, p. 22-31Article in journal (Refereed)
    Abstract [en]

    1. Despite the loss of natural ecosystems in the developed world during the past millennia, anthropogenic landscapes still sustain much biodiversity. Our question was, whether ten year changes in regional Odonata faunas are comparable between farmland and forested areas, or if the species pool of farmland areas respond in other ways than that of forest.

    2. We used data of dragonfly larvae collected from 16 lakes in a farmland area in south-western Sweden in the years 2002 and 2011/12, and compared these to data from 34 lakes in a forest area in south-eastern Sweden in the years 1996 and 2006.

    3. The species-richness in the agricultural region increased by 17% but decreased by 13% in the forested region. The changes in occurrence and regional distribution were similar in both areas, affecting 71% and 69% of the species pool. Average extinction rates were comparable between the agricultural and the forested region (38% and 43%) while colonisation rates differed greatly (64% and 114%).

    4. The species composition differed between the regions; the forest lakes harboured a 29% larger species pool. It is possible that in the forested region, the regional species pool in areas surrounding the study sites could stabilise the extinction and have a positive effect on changes in species composition. We assume that the different habitat structures of the waters in the agricultural and the forest regions and changes in temperature are the main driving forces behind the shifts. The mean seasonal air temperature has increased by circa 0.5°C in both regions, when comparing ten-year periods before each sampling year.

  • 24.
    Korkeamäki, Esa
    et al.
    Water and Environment Association of the River Kymi, Kouvola, Finland.
    Elo, Merja
    University of Jyväskylä, Jyväskylä, Finland.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Salmela, Jukka
    Regional Museum of Lapland, Rovaniemi, Finland.
    Suhonen, Jukka
    University of Turku, Turku, Finland.
    Regional variations in occupancy frequency distributions patterns between odonate assemblages in Fennoscandia2018In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 9, no 4, article id e02192Article in journal (Refereed)
    Abstract [en]

    Odonate (damselfly and dragonfly) species richness and species occupancy frequency distributions (SOFD) were analysed in relation to geographical location in standing waters (lakes and ponds) in Fennoscandia, from southern Sweden to central Finland. In total, 46 dragonfly and damselfly species were recorded from 292 waterbodies. Species richness decreased to the north and increased with waterbody area in central Finland, but not in southern Finland or in Sweden. Species occupancy ranged from 1 up to 209 lakes and ponds. Over 50% of the species occurred in less than 10% of the waterbodies, although this proportion decreased to the north. In the southern lakes and ponds, none of the species occurred in all lakes, whereas in the north many species were present in all of the studied waterbodies. The dispersal ability of the species did not explain the observed species occupancy frequencies, but generalist species with a large geographical range occurred in a higher percentage of the waterbodies. At Fennoscandian scale, we found that the unimodal satellite pattern was predominant. However, at smaller scale, we found geographical variations in odonate species SOFD patterns. The most southern communities followed the unimodal satellite-dominant pattern, whereas in other regions communities fitted best with the bimodal core - satellite patterns. It seems that the richer species pool in the southern locations, and the larger distribution range of the northern species, skewed the unimodal pattern into a bimodal satellite dominant pattern. © 2018 The Authors.

  • 25.
    Larsson, Matilda
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Ecology and Environmental Science.
    Inventering av Strandpadda (Bufo calamita) 2012 på Balgö och inom Varbergs kust2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 26.
    Lindén, Ann-Sofie
    et al.
    Halmstad University, School of Business and Engineering (SET).
    Uggla Viktorsson, Marcus
    Halmstad University, School of Business and Engineering (SET).
    Typ och grad av samband mellan skador på stammar och rötter av gran till följd av vildsvinsbök (troliga angreppspunkter för rotröta) och vildsvinspopulationens täthet2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Swedish wild boar (Sus scrofa) population has expanded greatly in both size and distribution during the last decades. It is well known that wild boar causes problems in the agriculture and several studies have been performed on this subject. However, there is almost no information concerning the importance of wild boar for the forestry. It is plausible that rooting could cause both rot (through physical damage to the roots) and influence the spread of rot between spruce plantations. If so, wild boar rooting could thereby lead to a loss in wood quality and harvested volumes and thus cause negative economic consequences for the forestry.This pilot study is a part of a larger research project on wild boar and its management. The aim of this study was, through a field study and annual statistics, to collect data indicating the type and degree of correlation between damage to the stems and roots due to wild boar rooting (probable attack point for rot) on spruce (Picea abies). Damage was related to the depth of the rooting, soil type, the age of the stand and an index for local wild boar density.The field study was conducted as an inventory of rooting along line transects with 50 meter intervals in spruce stands (age 30-70 years, landowner the forest enterprice Sveaskog). The inventories were conducted in southern Sweden in areas around Ulricehamn, Kalmar, Ljungby, Burseryd and Växjö.A total number of 683 wild boars rooting, in 40 different stands was recorded. Rooting with damaged roots and rooting with exposed roots are those that can lead to future rotting in spruce trees, and such made up 57% of all rootings. At rooting depth of 6-10 cm, the risk of such damages was >50% whereas at depths of 11-20, the risk was >70%. Of all rootings, 46% were located in stands on old agricultural land and 54% located at sites only used for forest regeneration. There was also a positive correlation between the number of years with wild boars in an area and the amount of rooting with damaged roots. The result shows that there is a risk that wild boar rooting, over time, could cause rot in spruce.

  • 27.
    Lundquist, Kristin
    Halmstad University, School of Business, Engineering and Science.
    Vildsvinsbök i skogsmark – en studie i tre områden i Mellansverige2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In April-July in 2010, three forest dominated areas in central Sweden were studied to investigate wild boar rooting habits. The results showed that rooting mainly occurred in pine-and spruce dominated habitats where tree-ages varied between 45-90 years old and with ground surface vegetation consisting of shrubs (blueberry/lingonberry), mosses and grass. In two of the three study areas the size of rooted areas was not affected by factors such as tree species composition, forest age or vegetation ground cover, but correlations between these factors were found in one of the areas. The size of rooted areas was not affected by the population density or the time with wild boar present in the area.

  • 28.
    Lundén, Eric
    Halmstad University, School of Business, Engineering and Science.
    Mossfloran vid vattenkvarnar i sydöstra Sverige2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Bryophytes play an important role in ecosystems in running waters and are common growing on structures in and around watermills. These watermill habitats differ from other parts of the watercourse in terms of microclimate and disturbance regime, and in providing more suitable and variable substrates. Bryophytes were sampled in and around five watermills and five reference sites 300 meters up or downstream from the watermill in the province Småland, in south-eastern Sweden. Species richness was compared between the sites and differences in community structure were analysed by a Discriminant Analysis. In 90% of the cases, the species composition was found to be specific for watermills and reference sites, and the mean species number was 57% higher at watermills than at the reference sites. Rocks and boulders in a wide range of sizes, concrete and mortar structures with pH-levels higher than that of the underlying bedrock, and stronger currents were identified as some of the causes of the higher diversity at the watermills. Restauration projects in rivers, including dam removal, constitute a potential threat to the bryophyte flora of watermills since the structures they grow on may either be removed or destroyed. Changes in microclimate and disturbance regime are other potential threats to species in these habitats.

  • 29.
    Persson, Linnéa
    Halmstad University, School of Business, Engineering and Science.
    Skyddsvärda kärlväxter i Haväng och Vitemölla strandbackar: – utbredning, hot och skötsel2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Semi-natural grasslands are one of the most threatened habitats in Scandinavia. The grassland in this study is situated in the northern part of the nature preserve of Haväng och Vitemölla strandbackar in the province of Skåne and consists of grey dunes and a pasture which partly consists of calcareous grassland and the vegetation type sand steppe which is very rare in Sweden. There are several threatened plants in the area and during the summer of 2017 their distribution was registered to be able to protect them during conservation management. The results showed that most of the area contained important species and the most important areas to protect were the sand steppe areas. This is probably due to the dry, sandy, calcareous and nutrient poor conditions in these areas which many of the threatened plants are connected to. Most of the threatened plants were found in abundance in the area but have a limited distribution in Sweden. The population of Eryngium maritimum however was very small and is threatened by extinction. The plants in the area are threatened by a long-term process of nutrient enrichment and continuous leakage of calcium which may lead to lower pH and a more nutrient rich soil which leads to a higher availability of phosphorous. This may lead to a change in species composition and loss of species richness. Continuous grazing, soil disturbance to expose lime-rich sand and also removal of litter to minimize the nutrient levels are needed to maintain favorable conditions in the area. However, the number of important species requires attention and careful planning, especially in the sand steppe areas. 

  • 30.
    Petersson, Linn
    Halmstad University, School of Business, Engineering and Science.
    Hur markegenskaper i produktionsskog påverkas av bök från vildsvin (Sus scrofa) i sydvästra Sverige2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A balance between large-scale and small-scale disturbance is important for maintaining species diversity on landscape level. Wild boar rooting contributes to small-scale disturbance when leaving patches bare of soil. Knowledge is scarce regarding their impact on soil properties in managed spruce forests in south-west Sweden. Therefore, the objective of this study was to determine the effects of wild boar rooting on soil physical and chemical properties, by taking soil samples from the centre, the edge and outside of disturbed patches. Rooting activities significantly increased soil moisture, organic matter, total N and pH but did not affect total P in this study. Areas with high number of disturbed patches had higher soil moisture and organic matter compared to areas with intermediate and few disturbed patches. These new soil characteristics can favour species diversity and ultimately increase productivity in managed forests. The results of this study indicate that wild boar activity contributes to more positive than negative effects in managed spruce forests and focus should therefore lie on preventing wild boar rooting in other areas more sensitive to this disturbance. It is also important to disseminate information and knowledge about the wild boar's positive and negative impact on managed forests in order to better prevent the negative effects and strengthen the positive ones.

  • 31.
    Pires, Mateus Marques
    et al.
    Ecology and Evolution Laboratory, Vale do Taquari University (UNIVATES), Lajeado, Rio Grande Do Sul, Brazil.
    Périco, Eduardo
    Ecology and Evolution Laboratory, Vale do Taquari University (UNIVATES), Lajeado, Rio Grande Do Sul, Brazil.
    Renner, Samuel
    Ecology and Evolution Laboratory, Vale do Taquari University (UNIVATES), Lajeado, Rio Grande Do Sul, Brazil.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Predicting the effects of future climate change on the distribution of an endemic damselfly (Odonata, Coenagrionidae) in subtropical South American grasslands2018In: Journal of Insect Conservation, ISSN 1366-638X, E-ISSN 1572-9753, Vol. 22, no 2, p. 303-319Article in journal (Refereed)
    Abstract [en]

    Climate change is predicted to affect the distribution of freshwater taxa, and stronger impacts are expected on endemic species. However, the effects of future climates on freshwater insects from the Neotropical region have been generally overlooked. In this study, the distribution of a damselfly (Cyanallagma bonariense, Odonata, Coenagrionidae) endemic to the subtropical South American grasslands (Pampa) was modelled in relation to future scenarios of high greenhouse gas emissions (RCP 8.5) for 2050 and 2070. For this purpose, ecological niche models were developed based on assumptions of limited dispersal and niche conservatism, and the projected distribution of C. bonariense was contrasted with the location of current protected areas (PAs) in the Pampa. A broad potential distribution of C. bonariense was indicated throughout the Pampa, and projections predicted a predominance of range contractions rather than range shifts in climatically suitable areas for C. bonariense in 2050 and 2070. Projections of suitable areas overlapped in central Argentina and southernmost Uruguay in these periods. Our results indicated a potential resilience of C. bonariense to future climate change, which is likely related to the low restrictions in habitat use of C. bonariense. In every projection, however, most PAs were expected to lose effectiveness, as by 2070 most PAs fall outside the range of the predicted distribution of C. bonariense. Thus, the creation or enlargement of PAs in these areas is recommended and these results represent an important information for the conservation of endemic freshwater insects under global warming scenarios in an overlooked Neotropical landscape. © Springer International Publishing AG, part of Springer Nature 2018

  • 32.
    Pålsson, Joakim
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Ecology and Environmental Science.
    Geografisk spridning och morfologisk variation hos Brachygaster minutus (Hymenoptera: Evaniidae) i Sverige2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 33.
    Renner, Samuel
    et al.
    Ecologia e Sensoriamento Remoto, Centro Universitário Univates, Lajeado-RS, Brazil.
    Perico, Eduardo
    Ecologia e Sensoriamento Remoto, Centro Universitário Univates, Lajeado-RS, Brazil.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS).
    Dragonflies (Odonata) in Subtropical Atlantic Forest fragments in Rio Grande do Sul, Brazil: seasonal diversity and composition2013In: Scientia Plena, ISSN 1808-2793, Vol. 9, no 1, article id 012401Article in journal (Other academic)
    Abstract [en]

    One of the most endangered ecosystems in America is the Atlantic Forest, which demands emergency actions to protect its remnants as well its biodiversity. In this situation the species inventory can develop a management role for the future, determining specific areas that should be preserved as well the species composition and richness can be used as an indicator of a healthy ecosystem. The use of dragonfly species composition has proven its potential indication of quality habitats. The Odonata species actually still poorly known in the Neotropical region and has never been used as a tool to analyze the actual conditions of aquatic environments particularly in the Subtropical Atlantic Forest, which occurs in south of Brazil. A systematic survey was carried out in aquatic systems located at remnants of forest from March 2011 to February 2012. A total of 565 specimens belonging to 34 species, distributed in 5 families were sampled. Libellulidae was dominant, with 14 species, followed by Coenagrionidae, Gomphidae, Lestidae and Aeshnidae. Through inventory survey we deepen the Odonata composition knowledge and performed a statistic analysis.

  • 34.
    Renner, Samuel
    et al.
    Universidade do Vale do Taquari, Bairro Universitário, Lajeado, RS, Brazil.
    Périco, Eduardo
    Universidade do Vale do Taquari, Bairro Universitário, Lajeado, RS, Brazil.
    Ely, Gerson
    Universidade do Vale do Taquari, Bairro Universitário, Lajeado, RS, Brazil.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Preliminary dragonfly (Odonata) species list from the Pampa biome in Rio Grande do Sul, Brazil, with ecological notes for 19 new records for the state2017In: Biota Neotropica, ISSN 1806-129X, E-ISSN 1676-0611, Vol. 17, no 4, article id e20170374Article in journal (Refereed)
    Abstract [en]

    An inventory of Odonata was carried out in the southern half of the state of Rio Grande do Sul, Brazil, in the Pampa biome. Originally, this biogeographical region was covered mostly by open fields and grassland, with sections of higher vegetation surrounding water bodies and rocky hills. Today the landscape is fragmented due to agricultural activities, mainly cattle farming, rice crops and forest plantations. Our survey was conducted in three municipalities from this region, between March 2015 and April 2016. Aiming at a general overview of the species composition, our sampling sites were selected on a wide basis, including lakes, bogs, temporary water bodies, small streams and river sections. Eighty two species of Odonata were collected comprising 40 genera and seven families. The dominant families were Libellulidae (56,1%), Coenagrionidae (24,5%) and Aeshnidae (7,3%). We found a diverse odonate assemblage, adding 19 new species records for the state of Rio Grande do Sul.

  • 35.
    Renner, Samuel
    et al.
    Laboratório de Ecologia e Evolução, Universidade do Vale do Taquari – Univates, Lajeado, Brazil.
    Périco, Eduardo
    Laboratório de Ecologia e Evolução, Universidade do Vale do Taquari – Univates, Lajeado, Brazil.
    S Dalzochio, Marina
    Laboratório de Ecologia e Evolução, Universidade do Vale do Taquari – Univates, Lajeado, Brazil.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Ecoregions within the Brazilian Pampa biome reflected in Odonata species assemblies2018In: Austral ecology (Print), ISSN 1442-9985, E-ISSN 1442-9993Article in journal (Refereed)
    Abstract [en]

    Based on vegetation composition, previous studies of the Pampa biome in southern Brazil have defined seven ecoregions within the area. Here, we test this ecoregion approach studying the semi-aquatic insect group Odonata in five of these regions, aiming at comparing the ecoregions to the more traditional environmental predictors of water quality and land cover. Based on a data set of occupancy comprising 99 species distributed between 131 localities, a one-way Permutational Multivariate Analysis of Variance was used to compare differences in the species composition between the ecoregions, followed by a Principal Component Analysis to visualize the variation. The composition varied significantly between all groups tested, and the ordination explained 61.8% of the variance. A partial redundancy analysis of ecoregions, land cover and water quality variables explained 71% of the variance in Odonata community structure. Ecoregion was the most important predictor, followed by water quality and land cover. Within these species assemblies, we could select certain species that were representative of a given ecoregion, to which their distribution within the Pampa biome was entirely or mainly confined. Of 24 representative species 41.7% were rare, while the rest were more abundant and, hence, easier to detect. We suspect that the differences found between the Pampa ecoregions might be due to geology, as such factors may be strong determinants of biodiversity. Specific ecological requirements at the family and genus levels also seemed to act selectively on the species compositions within the ecoregions. Today, the Pampa is highly fragmented due to agricultural activities such as rice cultivation, extensive cattle farming and forest plantations. We suggest that an ecoregion-based approach to the implementation of conservation measures may be the best way to help these distinct species assemblies survive.

  • 36.
    Renner, Samuel
    et al.
    Lab de Evolução e Ecologia, Centro Universitário Univates, Lajeado, RS, Brazil.
    Périco, Eduardo
    Lab de Evolução e Ecologia, Centro Universitário Univates, Lajeado, RS, Brazil.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Effects of exotic tree plantations on the richness of dragonflies (Odonata) in Atlantic Forest, Rio Grande do Sul, Brazil2016In: International Journal of Odonatology, ISSN 1388-7890, Vol. 19, no 4, p. 207-219Article in journal (Refereed)
    Abstract [en]

    One of the forest types occurring in Southern Brazil is the mixed ombrophilous forest (MOF), a subtype of the Atlantic Forest, which is one of the richest biomes on Earth. This biome currently remains as a highly fragmented mosaic, under pressure from human development. The diversity and ecology of most animal groups in this biome are poorly known. We studied Odonata in a large forest fragment, including an ecological reserve: the Floresta Nacional de São Francisco de Paula (FLONA-SFP), in Rio Grande do Sul, administrated by the Brazilian government. The reserve is dominated by MOF with sectors of Pinus elliottii and Araucaria angustifolia. Three surveys of these forest sectors over one year yielded 42 species, with the highest species richness recorded in the P. elliottii sector. The odonate species recorded here are all generalist in terms of habitat preferences, but they appeared only in low numbers and were very particular in their occurrence pattern. We therefore assume that the introduction of an alien element in the Atlantic Forest has given rise to a new species assemblage, where the ecology of the species is adapted to the novel habitat of Pinus plantations. As expected, the species occurring in the MOF sectors were mainly habitat specialists. The Araucaria plantations had an intermediate species composition. Despite the differences observed in habitat preference between generalist and specialist species, such exotic plantation habitats may act as a temporary biodiversity reservoir for further habitat colonization. © 2016 Worldwide Dragonfly Association

  • 37.
    Renner, Samuel
    et al.
    Ecologia e Sensoriamento Remoto, Centro Universitário Univates, Lajeado-RS, Brasil.
    Périco, Eduardo
    Ecologia e Sensoriamento Remoto, Centro Universitário Univates, Lajeado-RS, Brasil.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Man-made lakes form species-rich dragonfly communities in the Brazilian Atlantic Forest (Odonata)2016In: Odonatologica, ISSN 0375-0183, Vol. 45, no 3-4, p. 135-154Article in journal (Refereed)
    Abstract [en]

    One of the forest types occurring in Southern Brazil is the Mixed Ombrophilous Forest (MOF), a subtype of the Atlantic Forest and one of the biodiversity hotspots on Earth. We sampled adult Odonata at 30 locations in the Floresta Nacional de São Francisco de Paula (FLONA-SFP), Rio Grande do Sul, Brazil, a national reserve which is divided into several sectors of MOF, planted Araucaria angustifolia, Pinus elliottii used for sustainable and financial purposes, and open fields. There are three types of aquatic environments in the reserve: lakes, swamps, and rivers/streams. Our aim was to obtain an overview of the species’ distribution patterns in the three types of aquatic environments and to evaluate the species occurring in lakes, an exclusively man-made habitat in this area. We recorded 46 species from seven odonate families; 25 species (x = 5.71 ± 1.77 SD) occurring in rivers/ streams, 24 in lakes (11.57 ± 2.15) and 21 in swamps (5.22 ± 3.60). Using Non-metric Multidimensional Scaling (NmDS), we showed that the species composition differed clearly between the three types of aquatic habitats. While swamps and rivers/streams had a relatively similar and uniform species composition, species in the lakes were more varied but the total species number was almost as high as that of the rivers/streams. The lake communities also differed distinctly from those of the other habitats, and we assume that the lake species originate from other degraded areas in the vicinity, indicating that the remains of the Atlantic Forest has already been strongly altered by humans. Given the poor knowledge of the Odonata in the Atlantic Forest/MOF, we hope that our study may increase the understanding of the communities, and contribute to the development of conservation measures for this fragmented biome.

  • 38.
    Renner, Samuel
    et al.
    Universidade do Vale do Taquari, Lajeado, Brazil.
    Périco, Eduardo
    Universidade do Vale do Taquari, Lajeado, Brazil.
    Schmidt Dalzochio, Marina
    Universidade do Vale do Taquari, Lajeado, Brazil.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Water body type and land cover shape the dragonfly communities (Odonata) in the Pampa biome, Rio Grande do Sul, Brazil2018In: Journal of Insect Conservation, ISSN 1366-638X, E-ISSN 1572-9753, Vol. 22, no 1, p. 113-125Article in journal (Refereed)
    Abstract [en]

    The biogeographical region known as the Pampa biome in southern Brazil, was originally mainly covered with open fields or grassland, with areas of riparian forest surrounding the water bodies. Today this landscape appears highly fragmented due to agricultural activities such as rice cultivation, extensive cattle farming, and forest plantations. Studies have shown that the Pampa biome has high levels of biodiversity and endemism, but with regard to invertebrates, this biome is still one of the least known in Brazil. We therefore designed a study comparing the dragonfly (Odonata) communities to environmental and landscape features in this area, measuring diversity by species richness, relative abundance and Shannon index. Our results showed that the Pampa is a biome very rich in odonates, and that the species communities are highly dependent on the environmental conditions of the area. Habitats such as Rivers/Streams, bordered by native grasslands and riparian forests, were shown to harbour communities that were ecologically more complex and sensitive than other habitat types. Man-made lakes and agricultural areas displayed lower levels of biodiversity and odonate communities dominated by generalist species. By combining data on the communities of Odonata and other taxa, our analyses may be instrumental in determining priority areas for future conservation measures within the area. © 2018, Springer International Publishing AG, part of Springer Nature.

  • 39.
    Renner, Samuel
    et al.
    Lab de Evolução e Ecologia, Centro Universitário Univates, Lajeado, RS, Brazil.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS).
    Périco, Eduardo
    Lab de Evolução e Ecologia, Centro Universitário Univates, Lajeado, RS, Brazil.
    Testing Dragonflies as Species Richness Indicators in a Fragmented Subtropical Atlantic Forest Environment2015In: Neotropical Entomology, ISSN 1519-566X, E-ISSN 1678-8052, Vol. 45, no 3, p. 231-239Article in journal (Refereed)
    Abstract [en]

    We surveyed 15 bodies of water among remnants of the Atlantic Forest biome in southern Brazil for adult dragonflies and damselflies to test whether an empirical selection method for diversity indicators could be applied in a subtropical ecosystem, where limited ecological knowledge on species level is available. We found a regional species pool of 34 species distributed in a nested subset pattern with a mean of 11.2 species per locality. There was a pronounced difference in species composition between spring, summer, and autumn, but no differences in species numbers between seasons. Two species, Homeoura chelifera (Selys) and Ischnura capreolus (Hagen), were the strongest candidates for regional diversity indicators, being found only at species-rich localities in our surveyed area and likewise in an undisturbed national forest reserve, serving as a reference site for the Atlantic Forest. Using our selection method, we found it possible to obtain a tentative list of diversity indicators without having detailed ecological information of each species, providing a reference site is available for comparison. The method thus allows for indicator species to be selected in blanco from taxonomic groups that are little known. We hence argue that Odonata can already be incorporated in ongoing assessment programs in the Neotropics, which would also increase the ecological knowledge of the group and allow extrapolation to other taxa. © 2015, Sociedade Entomológica do Brasil.

  • 40.
    Sahlén, Göran
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS).
    Bernard, Rafal
    Department of General Zoology, Adam Mickiewicz University, Poznan, Poland.
    Rivera, Adolfo Cordero
    Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, EUET Forestal, Campus Universitario, Pontevedra, Spain.
    Ketelaar, Robert
    Dutch Butterfly Conservation / Dutch Society for the Preservation of Nature, Eindhoven, The Netherlands.
    Suhling, Frank
    Institute of Geoecology, Dpt of Environmental System Analysis, Technical University of Braunschweig, Braunschweig, Germany.
    Critical species of Odonata in Europe2004In: International Journal of Odonatology, ISSN 1388-7890, Vol. 7, no 2, p. 385-398Article in journal (Refereed)
    Abstract [en]

    The status of the odonate fauna of Europe is fairly well known, but the current IUCN Red List presents only six species out of ca 130, two of which are actually out of danger today. In this paper we propose a tentative list of 22 possibly declining or threatened species in the region. For the majority, reliable data of population size and possible decline is still lacking. Also 17 endemic species are listed, most occurring in the two centres of endemism in the area: the south-eastern (mountains and islands) and the western Mediterranean. These species should receive extra attention in future updates of the world Red List due to their limited distribution. The extreme variation in biomes and the human exploitation of habitats make conservation planning complicated in Europe. Within the EU, the FFH directive is a working tool aiding conservation. However, the species included do not fully correspond to those on the current Red List, nor to those discussed in this paper. We believe that future conservation efforts should focus on the most valuable and threatened habitats in each sub-region. Active conservation measures could be implemented on a European scale, provided that research will establish a solid ground for such measures. © 2004 Taylor & Francis Group, LLC.

  • 41.
    Sahlén, Göran
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS).
    Kalkman, Vincent J.
    Boudot, Jean-Pierre
    Bernard, Rafał
    Conze, Klaus-Jürgen
    De Knijf, Geert
    Dyatlova, Elena
    Ferreira, Sónia
    Jovic, Miloš
    Ott, Jürgen
    Riservato, Elisa
    European Red List of Dragonflies2010Report (Other academic)
    Abstract [en]

    The European Red List is a review of the conservation status of c.6,000 European species (mammals, reptiles, amphibians, freshwater fishes, butterflies, dragonflies, and selected groups of beetles, molluscs, and vascular plants) according to IUCN regional Red Listing guidelines. It identifies those species that are threatened with extinction at the regional level – in order that appropriate conservation action can be taken to improve their status. This Red List publication summarises results for European Dragonflies.

  • 42.
    Schmidt Dalzochio, Marina
    et al.
    Ecology and Evolution, University of Vale do Taquari, UNIVATES, Lajeado, Brazil.
    Périco, Eduardo
    Ecology and Evolution, University of Vale do Taquari, UNIVATES, Lajeado, Brazil.
    Renner, Samuel
    Ecology and Evolution, University of Vale do Taquari, UNIVATES, Lajeado, Brazil.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Effect of tree plantations on the functional composition of Odonata species in the highlands of southern Brazil2018In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 808, no 1, p. 283-300Article in journal (Refereed)
    Abstract [en]

    Changes in biodiversity have mainly been assessed using taxonomical diversity indices. Although these approaches contribute to the scientific understanding of species richness and composition patterns, trait-based metrics may be more useful for detecting responses to land use change. We used odonates as a model system to compare traits composition in mixed ombrophilous forest (MOF) and tree plantations: exotic species (Pinus sp.) and native species (Araucaria angustifolia). Our goal was to understand and compare how each vegetation type affects the selection of species traits, and which factors are responsible for the presence of the species in the environment. We recorded 36 Odonata species distributed across 14 functional groups. The functional composition varied between MOF and exotic tree plantations and was similar between these two habitats and native tree plantations. Native forest favoured specialist traits. Our results suggest that the conversion of MOF to tree plantations, especially exotic ones, results in a shift to less specialized Odonata communities with altered functional group composition. This result highlights the negative impact associated with the conversion of native forests into exotic plantations. Our results show that odonates with specialist traits are limited to natural forest sites, which makes the conservation of such areas crucial. © 2017 Springer International Publishing AG, part of Springer Nature

  • 43.
    Skoglund, Linda
    Halmstad University, School of Business and Engineering (SET).
    Artsamhällen av trollsländor (Odonata) i norrländska tjärnar: identifiering av möjliga indikatorarter för artmångfald2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A field study of dragonfly larvae was performed in 20 lakes situated in boreal forest in northern Sweden (in the southeast of Norrbotten county), accompanied by the study of several habitat variables within the locales; fish presence, composition of water vegetation, forestry and the distribution of Sphagnum moss. None of these variables had a proven effect on the species composition of Odonata. This may be due to the fact that species occurring in the north part of the country are generally more tolerant to environmental variables compared to species with a more southern focus of distribution. A shorter growth season implies prolonged life cycles and should in all probability bring about a greater need for habitat tolerance. When a species occurrence is not strictly random the species richness within a region increases/decreases as a result of the presence/absence of specific species which are sensitive to particular variables in their surroundings (deconstructive approach to species richness). Indicator species (indicating general species richness) were distinguished by implementing an analysis of nestedness and the result was compared to a similar study conducted for central Sweden (Sahlén and Ekestubbe, 2001). E. najas and L. quadrimaculata came forth as suitable indicator species for northern boreal freshwater habitats in this study. In the north they displayed specialist tendencies and were highly selective in their choice of habitats. The same species appears in a very different ecological context when localized to southern Sweden where they are considered trivial species. In addition, temporal follow-ups (repeated stocktakings) of the species composition of small freshwater habitats in this region, and the establishment of accompanying nestedness matrices will allow for the detection of ecological shifts within particular species. These would indicate ongoing restructuring of the Odonate communities and yield information about the impact of climate change.        

  • 44.
    Strand, John A.
    et al.
    Limnology, Lund University, Lund, Sweden.
    Weisner, Stefan
    Limnology, Lund University, Lund, Sweden.
    Wave exposure related growth of epiphyton: Implications for the distribution of submerged macrophytes in eutrophic lakes1996In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 325, no 2, p. 113-119Article in journal (Refereed)
    Abstract [en]

    The distribution of submerged macrophytes in eutrophic lakes has been found to be skewed towards sites with intermediate exposure to waves. Low submerged macrophyte biomass at exposed sites has been explained by, for instance, physical damage from waves. The aim of this study was to investigate if lower biomass at sheltered sites compared to sites with intermediate exposure to waves can be caused by competition from epiphyton. Investigations were performed in eutrophic lakes in southern Sweden. Samples of submerged macrophytes and epiphytic algae on the macrophytes were taken along a wave exposure gradient. The amount of epiphyton (AFDW) per macrophyte biomass decreased with increased exposure. Biomass of submerged macrophytes, on the other hand, increased with increased exposure until a relatively abrupt disappearance of submerged vegetation occurred at high exposures. Production of epiphytic algae was monitored on artificial substrates from June to September at a sheltered and an exposed site in three lakes. It was higher at sheltered sites compared with exposed sites. We suggest that epiphytic algae may be an important factor in limiting the distribution of submerged macrophytes at sheltered sites in eutrophic lakes.

  • 45.
    Strand, John A.
    et al.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Weisner, Stefan E.B.
    Limnology, Department of Ecology, Lund University, Lund, Sweden .
    Dynamics of submerged macrophyte populations in response to biomanipulation2001In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 46, no 10, p. 1397-1408Article in journal (Refereed)
    Abstract [en]

    1. A 6-year study (1992-97) of changes in submerged vegetation after biomanipulation was carried out in the eutrophicated Lake Finjasjon, Southern Sweden. Ten sites around the lake were revisited each year. At each site five samples of above-ground biomass were taken at 10 cm water depth intervals. An investigation of the seed bank at the 10 sites, and a grazing experiment where birds and large fish were excluded was also conducted. 2. Between 1992 and 1996, in shallow areas (water depth < 3 m), vegetation cover 2 increased from < 3 to 75% and above-ground biomass from < 1 to 100 g DW m(-2). Mean outer water depth increased from 0.3 to 2.5 m. Elodea canadensis and Myriophyllum spicatum accounted for > 95% of the increase in biomass and plant cover. The following year (1997), however, cover and above-ground biomass decreased, mainly attributable to the total disappearance of E. canadensis. Secchi depth increased after biomanipulation until 1996, but decreased again in 1997. 3. Total and mean number of submerged species increased after biomanipulation, probably as a result of the improved light climate. However, after the initial increase in species number there was a decrease during the following years, possibly attributed to competition from the rapidly expanding E. canadensis and M. spicatum. The lack of increase in species number after the disappearance of E. canadensis in 1997 implies that other factors also affected species richness. 4. A viable seed bank was not necessary for a rapid recolonization of submerged macrophytes, nor did grazing by waterfowl or fish delay the re-colonization of submerged macrophytes. 5. Submerged macrophytes are capable of rapid recolonization if conditions improve, even in large lakes such as Finjasjon (11 km(2)). Species that spread by fragments will increase rapidly and probably outcompete other species. 6. The results indicate that after the initial Secchi depth increase, probably caused by high zooplankton densities, submerged vegetation further improved the light climate. The decrease in macrophyte biomass in 1997 may have caused the observed increase in phosphorus and chlorophyll a, and the decrease in Secchi depth. We suggest that nutrient competition from periphyton, attached to the macrophytes, may be an important factor in limiting phytoplankton production, although other factors (e.g. zooplankton grazing) are also of importance, especially as triggers for the shift to a clear-water state.

  • 46.
    Strand, John A.
    et al.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Weisner, Stefan E.B.
    Limnology, Department of Ecology, Lund University, Lund, Sweden.
    Morphological plastic responses to water depth and wave exposure in an aquatic plant (Myriophyllum spicatum)2001In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 89, no 2, p. 166-175Article in journal (Refereed)
    Abstract [en]

    1 We investigated morphological responses of the submerged macrophyte Myriophyllum spicatum L. to water depth and wave exposure when grown in the same substrate at two sites in two eutrophic lakes. Periphyton production was 4-8 times higher at sheltered than at wave-exposed sites and its influence was further investigated in a glasshouse experiment. Morphological responses in both experiments were compared by allometric analyses, with shoot weight as covariate. 2 In the field study, plants shoots exhibited similar responses (increased plant height and branch length, and decreased branch number) to sheltered conditions as to deep water. The partitioning between above- and below-ground biomass however, differed, with below-ground decreasing with an increasing water depth, but increasing or remaining unaffected at sheltered compared with exposed conditions. 3 In the glasshouse experiment, plant responses to water depth were similar to those in the field study. Furthermore, plant height increased when plants were overgrown with periphyton. 4 High production of periphytic algae at sheltered sites appears to cause light limitation of macrophytes. However, other factors such as nutrient uptake also appears to determine morphological responses. At sheltered sites, where leaf nutrient uptake is reduced by abundant periphyton and thick boundary layers, plants allocate more biomass to roots. At deep and wave-exposed sites, the absence of periphyton allows plants to take up nutrients through their leaves and allocation of biomass to shoots increases photosynthesis. 5 Overall, relative allocation to shoot and root biomass appears to be primarily controlled by nutrient availability, whereas allocation of available shoot biomass to particular structures is controlled by light availability.

  • 47.
    Suhling, Frank
    et al.
    Dept. of Environ. System Analysis, Institut für Geoökologie, TU Braunschweig, Langer Kamp 19c, DE-38102 Braunschweig, Germany.
    Sahlén, Göran
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Ecology and Environmental Science.
    Kasperski, Judith
    Dept. of Environ. System Analysis, Institut für Geoökologie, TU Braunschweig, Langer Kamp 19c, DE-38102 Braunschweig, Germany.
    Gaedecke, Dunja
    Dept. of Environ. System Analysis, Institut für Geoökologie, TU Braunschweig, Langer Kamp 19c, DE-38102 Braunschweig, Germany.
    Behavioural and life history traits in temporary and perennial waters: comparisons among three pairs of sibling dragonfly species2005In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 108, no 3, p. 609-617Article in journal (Refereed)
    Abstract [en]

    Identifying and examining traits that influence the distribution of species is crucial to the understanding of community structure. Theory predicts that traits should differ between species that live in temporary and permanent waters because of differing major environmental variables; viz drying out and predator presence, respectively. Species, however, will also be influenced by their evolutionary history, i.e. by the traits of their common ancestors. We studied differences in life history and behaviour traits in a series of laboratory experiments using pairs of dragonfly species out of three genera of Namibian Libellulidae (Odonata) with one species from each type of habitat. As predicted, growth rates were significantly higher in the temporary water species compared to the permanent water species. Activity and foraging, in contrast, differed between the genera, but did not differ between the habitat types. Hence, our study implies that the behavioural traits are influenced by phylogenetic inertia rather than by the habitat variables, while growth rate is adapted to the habitat. We argue that in all three genera one species has diverged recently from a sister species that lives in the original habitat of the genus, which may be temporary waters in Crocothemis Brauer and in Orthetrum Newman, and permanent waters in Trithemis Brauer. The behavioural traits may therefore be less well adapted. Rapid growth may be the more relevant trait because it is crucial to survival in temporary waters.

  • 48.
    Suhling, Frank
    et al.
    Institut für Geoökologie, Technische Universität Braunschweig, Langer Kamp 19c, D-38106 Braunschweig, Germany.
    Sahlén, Göran
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Ecology and Environmental Science.
    Martens, Andreas
    Biology, Karlsruhe University of Education, Bismarckstrasse 10, D-76133 Karlsruhe, Germany.
    Marais, Eugene
    National Museum of Namibia, Windhoek, P.O. Box 1203, Windhoek, Namibia.
    Schütte, Carsten
    Institut für Geoökologie, Technische Universität Braunschweig, Langer Kamp 19c, D-38106 Braunschweig, Germany.
    Dragonfly Assemblages in Arid Tropical Environments: A Case Study from Western Namibia2006In: Biodiversity and Conservation, ISSN 0960-3115, E-ISSN 1572-9710, Vol. 15, no 1, p. 311-332Article in journal (Refereed)
    Abstract [en]

    Dragonflies have been proposed as indicators for the ecosystem health of freshwater wetlands. For their useful functioning as indicators it is, however, necessary to identify species compositions in specific habitats and species-habitat associations, particularly in the tropics, where such knowledge is still weak. We examined the dragonfly species composition of 133 localities in the arid environment of western Namibia. An analysis of nestedness indicated that distinct, and predictable patterns of species associations can be expected. Discriminant analyses revealed that most of the nine habitat types separated by structural and hydrological parameters are well discriminated by their dragonfly assemblages. Spring brooks in particular host a specific assemblage, which is threatened due to the habitat restriction of several species, as well as by recent habitat loss and degradation. Using a hierarchical method of several criteria we demonstrated the selection of a set of potential indicator species from the species set, most of these being useful indicators for spring brook assemblages. The conservation status of certain habitats and species is discussed. We propose that dragonflies will have a high indicator potential for threatened freshwater wetlands in such areas and may also serve as an indication of the sustainable use of water resources including evaluating measures to rehabilitate environments.

  • 49.
    Suhling, Ida
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS). Technische Universität Braunschweig, Braunschweig, Germany.
    Suhling, Frank
    Technische Universität Braunschweig, Braunschweig, Germany.
    Thermal adaptation affects interactions between a range-expanding and a native odonate species2013In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 58, no 4, p. 705-714Article in journal (Refereed)
    Abstract [en]

    1.Increasing temperature and invading species may interact in their effects on communities. In this study, we investigated how rising temperatures alter larval interactions between a naturally range-expanding dragonfly, Crocothemis erythraea, and a native northern European species, Leucorrhinia dubia. Initial studies revealed that C.erythraea grow up to 3.5 times faster than L.dubia at temperatures above 16 degrees C. As a result, we hypothesised that divergent temperature responses would lead to rapid size differences between coexisting larvae and, consequently, to asymmetric intraguild predation at higher ambient temperatures. 2. Mortality and growth rates were measured in interaction treatments (with both species present) and non-interaction controls (one species present) at four different temperature regimes: at an ambient temperature representative of central Germany, where both species overlap in distribution, and at temperatures increased by 2, 4 and 6 degrees C. 3.The mortality of C.erythraea did not differ between treatment and control. In contrast, mortality of L.dubia remained similar over all temperatures in the controls, but increased with temperature in the presence of the other species and was significantly higher there than in the controls. We concluded that L.dubia suffered asymmetric intraguild predation, particularly at increased temperature. Reduced growth rate of L.dubia in the interaction treatment at higher temperatures also suggested asymmetric competition for prey in the first phase of the experiment. 4.The results imply that the range expansion of C.erythraea may cause reduction in population size of syntopic L.dubia when temperature rises by more than 2 degrees C. The consequences for future range patterns, as well as other factors that may influence the interaction in nature, are discussed. © 2013 Blackwell Publishing Ltd.

  • 50.
    Svensson, Emma
    Halmstad University, School of Business, Engineering and Science.
    Humlors (Bombus spp.) möjlighet till fortlevnad utmed vägkanter intill cykelleder i Halmstad med omnejd2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    There is an ongoing negative trend on pollinator abundance worldwide due to different threats that affect their health and living conditions, such as pathogens and parasites in combination with different types of habitat loss among other factors. In this study I investigate if road verges adjacent to cycle paths could be a suitable environment for bumblebees (Bombus spp.) to thrive. 13 sites were sampled to find out what kind of diversity of bumblebees and flowering plants this type of habitat could hold by observing different aspects, e.g. shade and vegetation coverage together with species diversity and abundance. The results showed that shade coverage had an effect on the flower diversity at the sites and also that bumblebee species diversity as well as bumblebee abundance got affected by the diversity of flowers.

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