Work Package 1: Demographic structure in harvested ecosystems
Leader: Øystein Langangen, UiO
This WP will develop foodweb models for ecosystem dynamics including demographic structure of the interacting species. The model development will build on general stochastic frameworks for structured populations, such as integral projection models (continuous structure, such as size; 43), matrix projection models (discrete structure; 14, 44), and stage-based biomass models with continuous time (45, 46).
Since most organisms are structured with respect to age, size, or lifehistory stages due to ontogenetic development, these models will apply to a wide range of taxa. These demographic approaches will be used to evaluate ecosystem consequences of climate change and stage-based harvesting strategies. For instance, it is sometimes desirable to avoid changes in morphological traits such as body size (16), and to develop life history specific management strategies (e.g., for short-lived vs. long-lived species).
Two general questions we aim to answer are
i) what are the consequences of including demographic structure regarding effects of climate change and harvesting on ecosystem responses like resilience, alternative stable states, and strength of interaction between species?, and
ii) along which demographic variable should harvesting quotas be allocated to ensure ecosystem sustainability and long-term yields under different climate scenarios?
To test these ideas we have access to long-term data for all our case ecosystems.