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A genetic study of the European tree frog, Hyla arborea, in Denmark was undertaken to examine the population structure on mainland Jutland and the island of Lolland after a period of reduction in suitable habitat and population sizes. The two regions have experienced the same rate of habitat loss but fragmentation has been more severe on Lolland. Genetic(More)
Predicting which species will occur together in the future, and where, remains one of the greatest challenges in ecology, and requires a sound understanding of how the abiotic and biotic environments interact with dispersal processes and history across scales. Biotic interactions and their dynamics influence species' relationships to climate, and this also(More)
Rapeseed (Brassica napus) is a predominantly selfpollinated crop with about one-third outcrossing. The outcrossing rate may be influenced by environmental factors, and hence changes in the heterozygosity level of a variety may occur during multiplication. In an investigation on environmental variation in outcrossing, we estimated the outcrossing rate in the(More)
BACKGROUND Flower visiting insects provide a vitally important pollination service for many crops and wild plants. Recent decline of pollinating insects due to anthropogenic modification of habitats and climate, in particular from 1950's onwards, is a major and widespread concern. However, few studies document the extent of declines in species diversity,(More)
Exposure to copper pollution affects reproduction, growth and survival of earthworms. It is known that earthworms can cope with high copper burdens, but the distinction between physiological acclimation and evolutionary heritable changes and associated fitness consequences of the adaption to long-term copper exposure has rarely been studied. To investigate(More)
Previous studies have shown that the interactions between chemicals and climatic stressors can lead to synergistically increased mortality. In the present study, we investigated the effect of seven common environmental contaminants on survival at -6 and 15°C as well as on reproduction at 15°C in the earthworm Dendrobaena octaedra. Three classes of chemicals(More)
Almost all lumbricid earthworms (Oligochaeta: Lumbricidae) harbor species-specific Verminephrobacter (Betaproteobacteria) symbionts in their nephridia (excretory organs). The function of the symbiosis, and whether the symbionts have a beneficial effect on their earthworm host, is unknown; however, the symbionts have been hypothesized to enhance nitrogen(More)
In their natural habitat, animals are exposed to a variety of stress factors, including extreme temperatures, low water availability, and toxic stress from chemical pollutants. In this study we examined the interaction between realistic environmental levels of soil-copper contamination and realistic winter temperatures on survival of the cosmopolitan(More)
We investigated the combined effects of mercury (HgCl(2)) and acute heat on survival of the springtail Folsomia candida. The springtails were exposed to a range of aqueous concentrations (0-48 mg Hg(2+)/L) of HgCl(2) for 24 h. Subsequently, the same individuals were exposed to a range of high temperatures, from 20 to 35.5 degrees C. We found a highly(More)
The ability of Collembola to survive drought stress is crucial for their distribution in the terrestrial environment. Previous studies have suggested that several toxic compounds affect the drought tolerance of Folsomia candida in a synergistic manner and that these compounds have the feature in common that they elicit their toxicity by causing membrane(More)