Phenotypic variation and ecological dynamics

 

Variation among individuals that arises from growth in body size over ontogeny is commonly ignored in ecological research. However, individual development and ecological dynamics are inherently linked. Significant growth in body mass occurs in most animal taxa and is, in some form, always dependent on food. As individuals forage, food availability decreases, resulting in a population feedback on individual development and reproduction. My major study topics in this area of research include within-cohort (year-class) size variation and the dynamics of fish communities structured by size-dependent processes.

 

 

Size variation within cohorts

 

Size variation among individuals may develop even when individuals are born in the same environment, i.e. within a cohort. I have studied the sources and consequences of variation within and among cohorts through early ontogeny using eurasian perch (Perca fluviatilis) as study organism.                  

 

I have also studied the consequent occurrence of intra-cohort cannibalism following the development of size differences.

 

 

Size based community theory: The Baltic Sea food web

 

I use structured population models to study the dynamics of size-structured fish communities. Mainly I have studied the Baltic Sea sprat-herring-cod system, using physiologically structured population models. Specific issues include patterns of coexistence among competing species exhibiting size- and food-dependent growth, priority effects, facilitation of fisheries by natural predators and the role of niche shifts in predators for predator-prey dynamics.