|| 要旨トップ | 本企画の概要 |
|日本生態学会第60回全国大会 (2013年3月，静岡) 講演要旨
シンポジウム S05-1 (Lecture in Symposium/Workshop)
Foraging ecology provides a foundation for understanding how the temporal characteristics of resource subsidies mediate their ecological effects. Pulsed subsidies may push recipient consumers to the asymptote of their functional response, where digestive capacity constrains foraging opportunity. Here I present case studies from coastal watersheds of Alaska, USA, where spawning salmon generate pulsed subsidies for commercially and culturally important consumers. I summarize three different tactics that increase the foraging opportunity of consumers. Juvenile coho salmon exhibit behavioral thermoregulation, exploiting thermal heterogeneity in streams to increase their digestive capacity. Dolly Varden employ phenotype flexibility, increasing the size of their digestive organs during the resource pulse and atrophying organs during the inter-pulse period. Lastly, wide-ranging consumers including rainbow trout, grizzly bear, and Glaucous-winged gulls extend the duration of the resource pulse by tracking spatio-temporal variation in salmon run timing. These results emphasize that habitat heterogeneity and intra-specific diversity can have strong positive effects on the ability of consumers to exploit pulsed subsidies.