Accessible habitat for shorebirds: Factors influencing its availability and conservation implications

摘要: --We examined the relationship between water levels and accessible habitat, how habitat influenced Dunlin (Calidris alpina) Semipalmated Sandpiper pusilla) numbers in managed wetlands at Pea Island (North Carolina) Merritt (Florida) National Wildlife Refuges 1998 1999. At we experimentally manipulated levels, which also allowed us to examine effects of level fluctuations on prey base. We these relationships because access foraging by shorebirds is positively related length their tarsometatarsus, southeastern United States, small calidrids are a numerically important component two million migrants using inland wetlands. confirmed importance shallow waters for Sandpiper--numbers increased with increasing availability 0-4 cm habitat. Island, use was inversely variability depth cm. Minimizing frequency amplitude associated single-capped culverts necessary improve quality. After adjusting accessibility, spring requirements were met under nearly all abundance scenarios. identified targets that maximize Island. In contrast, winter not except one scenario. Seasonally low density contributed shortfall, suggesting allocating more primary management option. Manipulating did adversely affect eight shorebird species. Estimates other parameters (e.g., turnover rates, biomass) essential set implement realistic conservation goals.