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Michael P. Harris Doug Beare Reidar Toresen Leif Nøttestad Matthias Kloppmann Hendrik Dörner Kevin Peach Derek R. A. Rushton Judy Foster-Smith Sarah Wanless 《Marine Biology》2007,151(3):973-983
Since the early 2000s routine fish surveys have recorded increasing numbers of snake pipefish, Entelurus aequoreus, in the northeast Atlantic. Fishermen and divers have also commented on this increase and pipefish have started to appear
in the diet of seabirds and other marine predators. This paper collates information from these diverse sources and assesses
the current status of snake pipefish. We found compelling evidence of a dramatic increase in the abundance of snake pipefish
starting around 2003 and continuing up to the present (2006) and a range expansion northwards to Spitzbergen and the Barents
Sea. Since 2004 snake pipefish have been increasingly recorded in the diet of many species of seabird breeding in colonies
around the coast of the UK, and in Norway, Iceland and the Faeroe Islands. Information on the nutrient value of snake pipefish
is currently lacking but their rigid, bony structure makes them difficult for young seabirds to swallow and there are numerous
records of chicks choking to death. Thus, in the case of avian predators during the breeding season, it appears unlikely that
increased abundance of snake pipefish will provide a useful alternative prey. The reason for the rapid and dramatic increase
in numbers of snake pipefish is currently unclear but such events are characteristic of marine ecosystems and will almost
certainly have an effect on food web dynamics. 相似文献
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B. E. Crowley M. B. Blanco S. J. Arrigo-Nelson M. T. Irwin 《Die Naturwissenschaften》2013,100(10):943-956
The future of Madagascar’s forests and their resident lemurs is precarious. Determining how species respond to forest fragmentation is essential for management efforts. We use stable isotope biogeochemistry to investigate how disturbance affects resource partitioning between two genera of cheirogaleid lemurs (Cheirogaleus and Microcebus) from three humid forest sites: continuous and fragmented forest at Tsinjoarivo, and selectively logged forest at Ranomafana. We test three hypotheses: (H1) cheirogaleids are unaffected by forest fragmentation, (H2) species respond individually to disturbance and may exploit novel resources in fragmented habitat, and (H3) species alter their behavior to rely on the same key resource in disturbed forest. We find significant isotopic differences among species and localities. Carbon data suggest that Microcebus feed lower in the canopy than Cheirogaleus at all three localities and that sympatric Cheirogaleus crossleyi and C. sibreei feed at different canopy heights in the fragmented forest. Microcbus have higher nitrogen isotope values than Cheirogaleus at all localities, indicating more faunivory. After accounting for baseline isotope values in plants, our results provide the most support for H3. We find similar isotopic variations among localities for both genera. Small differences in carbon among localities may reflect shifts in diet or habitat use. Elevated nitrogen values for cheirogaleid lemurs in fragments may reflect increased arthropod consumption or nutritional stress. These results suggest that cheirogaleids are affected by forest disturbance in Eastern Madagascar and stress the importance of accounting for baseline isotopic differences in plants in any work comparing localities. 相似文献
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Conserving Compartments in Pollination Webs 总被引:2,自引:0,他引:2
Sarah A. Corbet 《Conservation biology》2000,14(5):1229-1231
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Ethan J. Temeles Kathryn C. Shaw Alexei U. Kudla Sarah E. Sander 《Behavioral ecology and sociobiology》2006,61(2):163-172
We examined the effects of nectar availability and competition on foraging preferences and revisit intervals of traplining female purple-throated caribs hummingbirds (Eulampis jugularis) to Heliconia patches shared by two individuals or visited solely by one individual. Birds at both shared and solitary patches preferred multiflowered to single-flowered inflorescences, but the magnitude of this preference depended on food availability and competition. During a year of low flower availability, females visited multiflowered inflorescences more frequently than single-flowered inflorescences only when nectar availability was experimentally enhanced; similarly, females at shared patches exhibited a significant preference for multiflowered inflorescences only after experimental increases in nectar availability. Experimental manipulations of nectar availability also had different effects on revisit intervals of birds at shared vs solitary patches. Birds at shared patches responded to patch-wide increases in nectar rewards by increasing the duration of their visit intervals, whereas birds at solitary patches did not. In contrast, birds at solitary patches responded to abrupt losses of nectar at flowers (simulating competition) by decreasing the duration of their visit intervals, whereas a bird at a shared patch did not alter its return interval. The contrasting results between shared vs solitary patches suggest that future studies of traplining behavior should incorporate levels of competition into their design. 相似文献
409.
Sarah R. Partan 《Behavioral ecology and sociobiology》2013,67(9):1523-1539
The study of multimodal communication has become an active and vibrant field. This special issue of Behavioral Ecology and Sociobiology brings together new developments in this rapidly expanding area. In this final contribution to the special issue, I look to the future and discuss ten questions in need of further work, touching on issues ranging from theoretical modeling and the evolution of behavior to molecular mechanisms and the development of behavior. In particular, I emphasize that the use of multimodal communication allows animals to switch between sensory channels when one channel becomes too noisy, and suggest that a better understanding of this process may help us both to understand the evolution of multisensory signaling and to predict the success of species facing environmental changes that affect signaling channels, such as urbanization and climate change. An expanded section is included on the effects of climate change on animal communication across sensory channels, urging researchers to pursue this topic due to the rapidity with which the environment is currently transforming. 相似文献
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