Related Experiment Videos
Evaluating habitat as a surrogate for population viability using a spatially explicit population model
Joshua J Lawler1, Nathan H Schumaker
1U.S. Environmental Protection Agency, 200 SW 35th Street, Corvallis, OR 97333, USA. lawler.joshua@epa.gov
Environmental Monitoring and Assessment
|May 15, 2004
Summary
Habitat quality is a poor surrogate for population performance in conservation planning. Spatially explicit models, incorporating landscape patterns, are crucial for developing better indices for species like Red-shouldered Hawks and Northern Goshawks.
Area of Science:
- Conservation Biology
- Wildlife Ecology
- Population Dynamics
Background:
- Conservation planning often relies on surrogate measures due to data limitations.
- Habitat quality is frequently used as a surrogate for complex population metrics like species richness or viability.
Purpose of the Study:
- To evaluate habitat quality as a surrogate for population performance in Red-shouldered Hawks (Buteo lineatus) and Northern Goshawks (Accipiter gentilis).
- To compare simple habitat quality metrics with population growth rates derived from spatially explicit models.
Main Methods:
- Utilized a spatially explicit population dynamics model to simulate hawk populations.
- Compared predictions from habitat quality measures against simulated population growth rates.
Main Results:
- Habitat quality was a poor predictor of simulated population growth rates for both hawk species.
- A small fraction of potential habitat acted as population sources (15% for Red-shouldered Hawks, 2% for Goshawks).
- Discrepancies were attributed to landscape patterns, forest fragmentation, and spatial arrangement of habitat patches.
Conclusions:
- Simple habitat quality measures are often inadequate surrogates for predicting population persistence.
- Spatially explicit population models are essential for understanding the influence of landscape context and developing improved conservation indices.