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[Thomas Daniel <danielt@u.washington.edu>]

Come One Come All !


Mathbio Proudly Presents

Mark Scheuerell who,
in 114 Kincaid Hall at 1230 Wed and Friday,
will speak on


Estimating spatial biases in ecosystem models

Understanding how energy and nutrients flow through food webs is a major
goal of ecosystems ecology. In particular, academic scientists and
managers alike would
like to predict the effect of perturbations to the food web (e.g.
nutrient loading or fishery exploitation) on ecosystem functions such as
primary production. Our
knowledge to date has been based on the premise that all organisms in
each trophic level (e.g. fish, zooplankton, phytoplankton) are
homogenously (or sometimes
randomly) distributed across space. We believe this to be untrue, but it
remains to be tested whether violations of this assumption cause changes
in the predictions of
ecosystem models. Furthermore, we do not know whether the human
activities we are trying to predict the outcome of may in turn change
the underlying spatial
distribution of organisms within an ecosystem. On Monday I will present
some relevant background information and field results from a
comprehensive survey of lakes
in western WA. On Friday I plan to present some results from a
simulation exercise aimed at deriving the biases inherent in the spatial
sampling of organisms in 3D,
and possibly outline an ecosystem model to be used for evaluating
changes in ecosystem fluxes brought about by changes in the spatial
distribution of predators and
prey.