Decadal declines in avian herbivore reproduction: density-dependent nutrition and phenological mismatch in the Arctic

摘要: A full understanding of population dynamics depends not only on estimation mechanistic contributions recruitment and survival, but also knowledge about the ecological processes that drive each these vital rates. The process in particular may be protracted over several years, can depend numerous complexities until sexually mature adulthood is attained. We addressed long-term declines (23 breeding seasons, 1992-2014) per capita production young by both Ross's Geese (Chen rossii) Lesser Snow caerulescens caerulescens) nesting at Karrak Lake Canada's central Arctic. During this period, there was a contemporaneous increase from 0.4 to 1.1 million adults colony. evaluated whether (1) density-dependent nutritional deficiencies pre-breeding females or (2) phenological mismatch between peak gosling hatch forage quality, inferred NDVI brood-rearing areas, have been behind decadal goslings. found that, years when arrived grounds with diminished nutrient reserves, proportional composition during reduced for species. Furthermore, increased quality contributed additively further production, addition caused delayed associated subsequent negative effects clutch size nest success. degree course our study because advanced vegetation phenology without corresponding advance Goose phenology. Vegetation significantly earlier warm surface air temperatures measured spring (i.e., 25 May-30 June). suggest condition arriving were population-level recruitment, leading recent attenuation growth Geese.