Northern Prairie Wildlife Research Center
Reproductive Success of Belding's Savannah Sparrows
in a Highly Fragmented Landscape
Preservation of wetlands is critical for many species. Avian species richness
has been correlated with wetland area in freshwater marshes, although not all
species are area-dependent (Brown and Dinsmore 1986, Celada and Bogliani 1995).
Despite the positive relationship between wetland area and avian diversity,
small wetlands are critical for poor dispersers, and modeling has shown that
loss of small wetlands can increase the extinction risk for certain taxa (Gibbs
1993). Moreover, habitat fragments that serve as population sinks may be important,
because they can augment the size of metapopulations and contribute to genetic
diversity (Howe et al. 1991, Fleischer 1995). In addition to effects on populations,
wetlands that are isolated from natural upland habitats may have lower biodiversity
(Burke and Gibbons 1995).
Although coastal salt marshes may not support a high diversity of breeding
birds compared with freshwater wetlands (Burger et al. 1982), they are critical
to wetland-dependant species such as Belding's Savannah Sparrows. Our results
underscore the need for restoration plans (Zedler 1996) that include the preservation
and enhancement of both large and small salt marsh ecosystems (Bildstein et
al. 1991, Erwin et al. 1995).
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