Cooperative Research Units
Education, Research And Technical Assistance For Managing Our Natural Resources
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Trophic Resource Portfoilio


September 2013 - August 2015


A basic goal of ecosystem-based management (EBM) is to account for species interactions and
the potential for harvest levels on target species to have indirect effects on others. An implicit assumption of most EBM strategies is that harvested species can be modeled as homogenous entities with interactions governed by their numerical abundance or biomass. However, recent research on species interactions suggests this assumption is flawed. Rather than occurring as homogeneous entities, many prey resources exhibit functional diversity in terms of where and when they are available to consumers. For example, genetically differentiated prey populations often exhibit differential timing in the life-cycle events that
make them available to consumers. Consumers benefit from phenological diversity in prey resources because it spreads foraging opportunities across space and time, enabling individuals to track a shifting
mosaic of food rather than get swamped by a single pulse.
Recent studies suggest many wide-ranging consumers depend not only on phenological diversity in prey resources, but also on habitat connectivity, which enables them to track shifting prey phenologies across heterogeneous landscapes. The goal of this proposal is to explore whether these recent discoveries
in ecology have substantial implications for how we manage ecosystems. As we experience rapid losses to population diversity and widespread habitat fragmentation, a key uncertainty is in understanding how much trophic diversity and habitat connectivity is necessary to support consumers at the top of the food chain. This question is especially important in coastal ecosystems of North America, where recent
research shows that phenological diversity in commercially harvested salmon may provide benefits to wide-ranging consumers including grizzly bears, rainbow trout, and eagles. Habitat loss and homogenization, hatchery supplementation, and climate change have the potential to alter salmon phenologies and the mobility of consumers. I propose to address these issues by generating consumerresource
models that consider trophic resources not as a homogenous entity, but instead as an aggregate of stocks analogous to a financial portfolio.


Current Staff

Federal Staff: 95

Masters Students: 239

Phd Students: 142

Post Docs: 53

University Staff: 240

5 Year Summary

Students graduated: 701

Scientific Publications: 1936

Presentations: 4260



Funding Agencies

  • Society for Conservation Biology


Cooperative Research Units Program Headquarters Cooperators

  1. U.S. Geological Survey