Decadal declines in avian herbivore reproduction : Density-dependent nutrition and phenological mismatch in the Arctic / Megan V. Ross, Ray T. Alisauskas, David C. Douglas, and Dana K. Kellett.
Material type:
TextSeries: Ecology. 98(7): 1869-1883 Publication details: 2017Description: 28 cmLOC classification: - ROS
| Item type | Current library | Collection | Call number | Status | Date due | Barcode |
|---|---|---|---|---|---|---|
Electronic Journal
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IWWR Supported Research | Non-fiction | ROS (Browse shelf(Opens below)) | Available | 16909 |
Includes bibliographical references (pages 1880-1883)
A full understanding of population dynamics depends not only on estimation of
mechanistic contributions of recruitment and survival, but also knowledge about the ecological
processes that drive each of these vital rates. The process of recruitment in particular may be
protracted over several years, and can depend on numerous ecological complexities until
sexually mature adulthood is attained. We addressed long-term declines (23 breeding seasons,
1992–2014) in the per capita production of young by both Ross’s Geese (Chen rossii) and
Lesser Snow Geese (Chen caerulescens caerulescens) nesting at Karrak Lake in Canada’s central
Arctic. During this period, there was a contemporaneous increase from 0.4 to 1.1 million
adults nesting at this colony. We evaluated whether (1) density-dependent nutritional deficiencies
of pre-breeding females or (2) phenological mismatch between peak gosling hatch and
peak forage quality, inferred from NDVI on the brood-rearing areas, may have been behind
decadal declines in the per capita production of goslings. We found that, in years when prebreeding
females arrived to the nesting grounds with diminished nutrient reserves, the proportional
composition of young during brood-rearing was reduced for both species. Furthermore,
increased mismatch between peak gosling hatch and peak forage quality contributed additively
to further declines in gosling production, in addition to declines caused by delayed nesting with
associated subsequent negative effects on clutch size and nest success. The degree of mismatch
increased over the course of our study because of advanced vegetation phenology without a
corresponding advance in Goose nesting phenology. Vegetation phenology was significantly
earlier in years with warm surface air temperatures measured in spring (i.e., 25 May–30 June).
We suggest that both increased phenological mismatch and reduced nutritional condition of
arriving females were behind declines in population-level recruitment, leading to the recent
attenuation in population growth of Snow Geese.