Effects of river otter activity on terrestrial plants in trophically altered Yellowstone Lake.

摘要: Animals that deposit aquatically derived nutrients on terrestrial landscapes link food webs and affect a variety of in situ processes. This phenomenon, however, is poorly documented freshwater habitats, especially where species introductions have drastically changed an ecosystem's trophic structure. In this study, we used stable isotopes to document water-to-land nutrient transport by river otters (Lontra canadensis) around Yellowstone Lake, ecosystem recently altered nonnative invasions. We then investigated the effects otter fertilization plant growth prevalence at latrine (scent-marking) sites evaluated how recent changes lake's web could influence these responses. Values delta15N were higher latrines compared non-latrine five seven sample taxa. Additionally, grasses had percentage N than those from non-latrines. Foliar positively related fecal deposition rate for some plants, indicating increased scent-marking led rise values. Logistic regression models indicated selected well-shaded with access foraging. Atypical latrines, misclassified as non-latrines models, values similar correctly classified suggesting site alone cannot explain elevated sites. No difference diversity or percent cover N-fixing taxa occurred between nonlatrine sites, though specific genera did differ types. Measurements shoot lengths currants (Ribes sp.). twofold reduction numbers result even greater decline may become less social system decreased prey availability. Our results highlight role animals linking aquatic habitats inland systems suggest ongoing structure Lake unexpected ramifications well beyond lake itself.