addresses the need to describe the relationship between habitat and biota (’’habitat/suitability 
models") at appropriate spatial scales and with sufficient detail and resolution to quantify the 
effects of both incremental and catastrophic habitat alteration. The second step involves 
integrating habitat alteration effects with those of other stressors ("integration within a spatial 
context"), so that resource protection and restoration priorities can be evaluated at spatial scales 
up to and including regions or large receiving bodies. 
For this project, the focal species was selected partly to take advantage of existing data that may 
permit the development of linkages between habitat and biological fitness. Specifically, fine- 
scaled spatially-referenced information on presence and condition of individual loons across 
large geographic areas is available through long-term loon monitoring programs that exist in the 
upper Midwest and the Northeast. In addition to information from these programs, available 
monitoring databases and/or aerial photographs, provide information to characterize habitat 
quality. For loons, key habitat characteristics may include the presence of suitable nesting and 
brood rearing sites, measures of human disturbance, density or extent of human dwellings and 
other activities around lakes, turbidity, and availability of suitable forage fish supplies. This 
unique set of spatially-referenced data will permit the development of habitat suitability 
approaches and models, relating environment factors and biological condition. 
Within the loon project, integration within a spatial context has been approached through the 
development and application of spatially-explicit population models that incorporate stressor- 
response relationships that will be applied within the spatially-diverse landscape. Specifically, 
within this project, spatial models will be used to evaluate how loon life history, spatial 
heterogeneity, and interactions among stressors in the landscape drive the relationship among 
breeding success on individual lakes and population trends across broad regions. These models 
will be used to: 1) define what constitutes a population (within the context of the assessment 
question) and how sub-populations interact in a heterogeneous landscape, 2) determine the 
appropriate spatial scale for assessment questions, and 3) determine the relative risks presented 
by different stressors. This model development would be a primary objective of this 
demonstration project. 
Products 
As defined within this plan, these specific products will be developed: 
APM 2B FY04 Habitat suitability indices to support population models for projecting relative 
risks of multiple stressors including toxic chemicals and habitat alteration to common loons 
(AED). 
Also see Section 7 Toxic Chemicals, Project B3 for associated products. 
Benefits of Research 
This research will allow explicit evaluation of multiple stressors on piscivorous wildlife and lead 
to the development of risk-based criteria. This will be of direct benefit to Program Offices, 
Regions, and interagency efforts to protect important wildlife species. More broadly, this 
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