River food web phenology

Description

Food web phenology in a changing climate: a trophic dynamics and bioenergetics approach Warming temperatures associated with global climate change are altering the phenology, or timing, of species life history events worldwide. Differential responses among interacting species have the potential to alter the structure and function of biological communities and ecosystems. Understanding how emerging phenological asynchrony among species scales from population responses to higher level ecological dynamics is a priority question in global change research. This project seeks to understand how changing patterns of summer river temperatures, from warming air temperatures and reduced mountain snowpack, alter the phenology of riverine food webs. Riverine organisms are presently understudied from a phenological change perspective but may be particularly susceptible to warming temperatures due to their life history characteristics. We will measure the timing of peak biomass, productivity and energy demand (of trout) across multiple trophic levels (algae, aquatic invertebrates, trout) over multiple years in the East River at Gothic, CO, as well as several other nearby rivers in a space-for-time approach, to assess the effects of warming water temperatures on patterns of phenological synchrony in riverine food webs. The basic premise of this study is that warming will not affect the phenology of algal populations (light controlled), the main source of stream primary production, but will advance aquatic insect emergence (season biomass loss from the stream) and peak insect productivity, resulting in a mismatch between trout energetic demand and their main prey source.