| 11. |
- Arvidsson, Fredrik, et al.
(författare)
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Geographic location, not forest type, affects the diversity of spider communities sampled with malaise traps in Sweden
- 2016
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Ingår i: Annales Zoologici Fennici. - : Finnish Zoological and Botanical Publishing Board. - 0003-455X .- 1797-2450 .- 0003-3847. ; 53:3-4, s. 215-227
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Tidskriftsartikel (refereegranskat)abstract
- The latitudinal diversity gradient predicts higher species richness at lower latitudes. Here, we utilize the data from a long-term monitoring with malaise traps to analyse if spider communities in Sweden are affected by geographic gradients and if these effects hold independent of forest type. The species richness and the effective number of species in spider communities were not significantly related to the latitudinal gradient. The effective number of species and the taxonomic distinctness of spider communities were related to longitude, with a higher number, but fewer related species in western parts of Sweden. The species and family composition were significantly related to latitude independent of forest type, with a dominance of Linyphiidae individuals and species in the north. Our study demonstrates the suitability of malaise trap sampling to contribute to a better understanding of local spider communities, as several rare and locally new species were recorded in this study.
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| 12. |
- Arzel, Céline, et al.
(författare)
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Early springs and breeding performance in two sympatric duck species with different migration strategies
- 2014
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Ingår i: Ibis. - : Wiley: 12 months. - 0019-1019 .- 1474-919X. ; 156:2, s. 288-298
-
Tidskriftsartikel (refereegranskat)abstract
- The capacity of migratory species to adapt to climate change may depend on their migratory and reproductive strategies. For example, reproductive output is likely to be influenced by how well migration and nesting are timed to temporal patterns of food abundance, or by temperature variations during the brood rearing phase. Based on two decades (1988–2009) of waterfowl counts from a boreal catchment in southern Finland we assessed how variation in ice break-up date affected nesting phenology and breeding success in two sympatric duck species, Mallard Anas platyrhynchos and Eurasian Teal Anas crecca. In Fennoscandia these species have similar breeding habitat requirements but differ in migration distance; Teal migrate roughly seven times as far as do Mallard. Annual ice break-up date was used as a proxy of spring ‘earliness’ to test the potential effect of climate change on hatching timing and breeding performance. Both species were capable of adapting their nesting phenology, and bred earlier in years when spring was early. However, the interval from ice break-up to hatching tended to be longer in early springs in both species, so that broods hatched relatively later than in late springs. Ice break-up date did not appear to influence annual number of broods per pair or annual mean brood size in either species. Our study therefore does not suggest that breeding performance in Teal and Mallard is negatively affected by advancement of ice break-up at the population level. However, both species showed a within-season decline in brood size with increasing interval between ice break-up and hatching. Our study therefore highlights a disparity between individuals in their capacity to adjust to ice break-up date, late breeders having a lower breeding success than early breeders. We speculate that breeding success of both species may therefore decline should a consistent trend towards earlier springs occur.
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| 13. |
- Back, C, et al.
(författare)
-
High-dosage treatment of a Quebec stream with Bacillus thuringiensis serovar. israelensis : efficacy against black fly larvae (Diptera, Simuliidae) and impact on nontarget insects
- 1985
-
Ingår i: Canadian Entomologist. - 0008-347X .- 1918-3240. ; 117:12, s. 1523-1534
-
Tidskriftsartikel (refereegranskat)abstract
- A typical lake outlet of the Canadian Shield was treated for 15 min with a high dose (5.28 g/L s−1 of discharge) of Teknar®, a commercial formulation of Bacillus thuringiensis serovar. israelensis. Efficacy on Simuliidae larvae and impact on non-target aquatic insects of this stream were monitored using drift nets, counting plates, and artificial turf substrates along a 1000-m section downstream of the site of application. Compared with a 4-day pre-treatment average for 12-h sampling periods, drift of Simuliidae increased from 64 to 92 ×, with shorter peaks of 133–184 ×, 2–6 h after treatment. There was no evident drift increase in larvae of Ephemeroptera, Plecoptera, Trichoptera, Chironomidae, or dipterous pupae, but larvae of Blephariceridae (Diptera) were severely affected as their drift was increased by up to 50 × and remained high for 3 days. After 30 h the mortality of Simuliidae on counting plates ranged from 95 to 82% in the first 300 m, with detachment rates of 78.5–46.5%. Densities of non-target insect larvae were not reduced on the artificial substrates, except for 2 genera of Chironomidae (Eukiefferella and Polypedilum) which were reduced 26 to 39% of their original density. Drifting larvae of 1 chironomid genus (Phaenopsectra) also showed symptoms of toxemia by B.t.i. The main impact of the treatment was thus seen in 2 Nematocera families (Chironomidae and Blephariceridae) which were mainly exposed to B.t.i. sedimented on the bottom of the stream or attached to periphyton growing on rocks.
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| 14. |
- Björklund, Erland, et al.
(författare)
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Biologiske metoder for nedbryting av medisinrester i gjødsel
- 2017
-
Rapport (populärvet., debatt m.m.)abstract
- Det er lite kunnskap om medisinrester i norsk hestemøkk. I dette prosjektet har vi videreutviklet en analysemetode som kan analyse for ulike antibiotika og parasittmidler i samme prøve. Metoden er utviklet og testet slik at den kan brukes på fast substrat som hestemøkk. Hestemøkk fra medisinerte hester og hestemøkk tilsatt kjente mengder medisiner ble kompostert ute i en ranke bestående av hestemøkk og nyslått gras. I et potteforsøk, ble noe av hestemøkken fra medisinerte hester tilsatt kompostmeitemark for å se hvordan de bearbeidet medisinrestene. - Flere medisiner til husdyr ble vurdert i starten og det er utviklet analysemetode for flere virkestoffer i medisiner mest vanlig brukt til hest. Antibiotikumet Tribrissen vet inj med virkestoffene trimetoprim og sulfadiazin, og parasittmidlene Panacur med virkestoffet fenbedazol, og Banminth med virkestoffet pyrantelembonat til hest, ble med i hele forprosjektet. 70 prøver av hestemøkk og hestemøkkompost ble analysert. Vi fant at man kan analysere tørket hestemøkk fra medisinerte hester, prøvene trenger dermed ikke frysetørkes for videresending til analyse. Analysemetoden kan brukes for å analysere alle 4 virkestoffene samtidig. - Det er høyest restinnhold i hestemøkk 1-2 dager etter at hesten er behandlet, men litt ulikt for hvert stoff. Deretter reduseres mengden raskt i møkk fra hestene. Nedbrytingen av medisiner tar tid i de komposteringsmetodene som ble testet. I rankekomposten avtok innholdet av medisiner utover i perioden på 60 dager. Det var litt ulike nedbrytingskurver for de ulike stoffene. Tre av stoffene var det enda rester av i komposten etter 60 dager. Forsøket med bruk av kompostmeitemark må optimaliseres og gjøres på nytt, mellom annet fordi mange av meitemarkene døde i ledd med ubehandlet hestemøkk. - Våre utprøvinger viser at møkk fra behandla hester bør skilles fra annen møkk de første 1-3 dagene etter behandling. Det må utvikles håndteringsstrategier for denne møkken slik at den kan brukes trygt i plantedyrking. Det må flere utprøvinger til mht omdanningshastighet av medisinrester ved ulike komposteringsmetoder. Både temperaturutvikling, størrelsen på kompostranken, fuktighetsforhold og overlevelse av kompostmeitemark er viktige faktorer som vi må vite mer om under norske forhold. Innholdet i urin ble ikke testet. - Vi gjennomførte en spørreundersøkelse om jord og gjødsel blant 100 hagesenterkunder. Den viste at det er en viss interesse for torvfrie, lokalproduserte jord- og gjødselprodukter, rundt halvparten av de spurte var villige til å betale 20 % merpris for et slikt produkt. Undersøkelsen viste at forbrukerne ønsket jord og gjødsel som er næringsrik og hvor ett produkt kan brukes til flere formål. - Dette prosjektet har hatt stor betydning for samarbeidspartene ved å utvikle analysemetode for medisinrester i fast hestemøkk, videre har vi lagt et grunnlag for å videreutvikle hestegjødsel som et produkt uten medisinrester.
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| 15. |
- Brodin, Anders, et al.
(författare)
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Optimal energy allocation and behaviour in female raptorial birds during the nestling period
- 2003
-
Ingår i: Ecoscience. - : University Laval. - 1195-6860. ; 10:2, s. 140-150
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Tidskriftsartikel (refereegranskat)abstract
- In many raptors and owls the male is the main provider of food in the early phase of the nestling period while the female incubates the eggs and broods the young. In the nestling period the female often helps the male to feed the young, but the factors affecting whether and when she leaves the brood to hunt have not been investigated in detail. We present a dynamic state variable model that analyses female behaviour and fat storage dynamics over the nestling period. The results show that in the first half of the nestling period the female faces a conflict between the need to brood the young and the need to hunt to provision them with food. This conflict arises because the energy needs of the young peak early in the nestling period, at a time when they still cannot thermoregulate and therefore need brooding from the female. The most critical period is the second nestling week, when both female and nestling fat reserves will decrease to low levels. Large female fat reserves in the early nestling period provide a solution to this conflict and are essential for successful breeding. Stochasticity in male provisioning is thus not needed to explain why females should be fat when the eggs hatch. Under normal circumstances, the female broods during the first two weeks and leaves the young only if hunting is absolutely necessary. After the second week the energy requirements are relaxed, and whether the female assists the male in hunting or not depends on factors such as male hunting success, environmental stochasticity, and energy requirements of the young. Our model provides a framework for empirical investigations on female behaviour during breeding in raptors, owls, and other birds with marked division of labour.
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| 16. |
- Chauvet, Eric, et al.
(författare)
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Litter decomposition as an indicator of stream ecosystem functioning at local-to-continental scales : insights from the European RivFunction project
- 2016
-
Ingår i: Large-scale ecology. - London : Academic Press. - 9780081009352 ; 55, s. 99-182
-
Bokkapitel (refereegranskat)abstract
- RivFunction is a pan-European initiative that started in 2002 and was aimed at establishing a novel functional-based approach to assessing the ecological status of rivers. Litter decomposition was chosen as the focal process because it plays a central role in stream ecosystems and is easy to study in the field. Impacts of two stressors that occur across the continent, nutrient pollution and modified riparian vegetation, were examined at > 200 paired sites in nine European ecoregions. In response to the former, decomposition was dramatically slowed at both extremes of a 1000-fold nutrient gradient, indicating nutrient limitation in unpolluted sites, highly variable responses across Europe in moderately impacted streams, and inhibition via associated toxic and additional stressors in highly polluted streams. Riparian forest modification by clear cutting or replacement of natural vegetation by plantations (e.g. conifers, eucalyptus) or pasture produced similarly complex responses. Clear effects caused by specific riparian disturbances were observed in regionally focused studies, but general trends across different types of riparian modifications were not apparent, in part possibly because of important indirect effects. Complementary field and laboratory experiments were undertaken to tease apart the mechanistic drivers of the continental scale field bioassays by addressing the influence of litter, fungal and detritivore diversity. These revealed generally weak and context-dependent effects on decomposition, suggesting high levels of redundancy (and hence potential insurance mechanisms that can mitigate a degree of species loss) within the food web. Reduced species richness consistently increased decomposition variability, if not the absolute rate. Further field studies were aimed at identifying important sources of this variability (e.g. litter quality, temporal variability) to help constrain ranges of predicted decomposition rates in different field situations. Thus, although many details still need to be resolved, litter decomposition holds considerable potential in some circumstances to capture impairment of stream ecosystem functioning. For instance, species traits associated with the body size and metabolic capacity of the consumers were often the main driver at local scales, and these were often translated into important determinants of otherwise apparently contingent effects at larger scales. Key insights gained from conducting continental scale studies included resolving the apparent paradox of inconsistent relationships between nutrients and decomposition rates, as the full complex multidimensional picture emerged from the large-scale dataset, of which only seemingly contradictory fragments had been seen previously.
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| 17. |
- Dessborn, Lisa, et al.
(författare)
-
Geese as vectors of nitrogen and phosphorus to freshwater systems
- 2016
-
Ingår i: INLAND WATERS. - 2044-2041 .- 2044-205X. ; 6:1, s. 111-122
-
Tidskriftsartikel (refereegranskat)abstract
- Many goose populations have increased dramatically over the past decades, which may influence inland waters used as roost sites. We reviewed the role of geese in the influx of nitrogen and phosphorus to freshwater systems. Several methods have been used to estimate guanotrophication impacts of geese. Water and sediment analysis have been conducted in areas of high and low geese presence; however, productive wetlands tend to attract more birds, and the causality is therefore ambiguous. Faecal addition experiments have attempted to estimate the impacts of droppings on water chemistry, sediments, algal growth, or invertebrate densities. The most common method of estimating goose guanotrophication is by extrapolation, usually based on multiplication of faecal production and its nutrient content. Based on such studies and those including information about daily migration patterns, we developed an approach to improve estimates of the nutrient contribution of geese. The relative role of geese in wetland eutrophication is also affected by the influx from alternative sources. The greatest guanotrophication impacts are likely found in areas with few alternative nutrient sources and with large goose flocks. Limited inflow and outflow of a freshwater system or a scarcity of wetland roosts may also increase problems at a local scale. Although several studies have looked at the impacts of geese on, for example, water chemistry or soil sediments, the effects are often smaller than expected, in part because no study to date has assessed the ecosystem response by including impacts on all levels, including water nutrient levels, nutrient sedimentation, chlorophyll content, and zooplankton response.
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| 18. |
- Djerf, Henric, et al.
(författare)
-
Inventeringsfiske i Arkelstorpsviken : 13-17 Augusti 2019
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Arkelstorpsviken är en grund och kraftigt övergödd vik. Som efter sjö sänkningen är avskild från Oppmannasjön med en kanal på 1 km. Vid den norra stranden ligger samhället Arkelstorp. Under åren 2018-2020 driver Oppmanna Vånga byggderåd ett LEADER projekt tillsammans med Högskolan Kristianstad. Projektet syftar till att ta reda på varför sjön är kraftigt övergödd och vad som är lämpliga åtgärder för att bättra vatten kvaliteten. Arkelstorpsviken är intressant då miljöövervakningen indikerar att stora mängder näringsämne lämnar vikennedströms. Dessa näringsämnen hamnar först i Ivösjön men sedan i Hanöbukten. Denna undersökning är gjord som del i LEADER projektet för att få en inblick hur den ekologiska statusen är i Arkelstorpsviken.
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| 19. |
- Elmberg, Johan, et al.
(författare)
-
Density dependent breeding success in mallards
- 2003
-
Konferensbidrag (refereegranskat)abstract
- Breeding success in wild mallards was studied on small eutrophic nemoral lakes in a two-year cross-over experiment in which wing-clipped conspecifics were added to increase pair density. The number of wild mallards that came to the lakes to nest (prior to introductions) did not differ between years. Introduction treatment led to a significant reduction in brood number in wild mallards, but it did not alter the number of stage 2+ ducklings finally produced on a lake. Introduction had no effect on lake utilization by broods, ducklings and non-breeding adults (cumulative days over the entire breeding season). Abundance of invertebrate prey differed greatly among lakes, but it did not correlate with breeding success. Breeding success was thus subject to sequential density-dependence; i.e. a lower number of broods still produced the same number of 2+ ducklings. We speculate that predation is the most likely process behind both patterns. We conclude that late and snapshot measures of duckling productivity may mask density dependent population processes of fundamental importance to regulation and harvest policy.
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| 20. |
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