Document: LAU-3-82-26

Spatial dispersion of migratory shorebirds at the continental scale: Implications for conservation.

PAYNE, L.X.* ¹, B.A.HARRINGTON ² and S.A.TEMPLE ¹

University of Wisconsin, Madison WI 53706 USA ¹
Manomet Center for Conservation Sciences, Manomet MA 02345 USA ²

Abstract:
To date, most efforts to protect migratory shorebirds have been site-based, with emphasis on identification and protection of traditional migratory 'hotspots.' While practical from a conservation standpoint, this classic approach under-represents species that are dispersed, or those that are distributed on the landscape in different ways during different years. Using 20 years of International Shorebird Survey data collected at 1000 wetlands in the conterminous United States, we quantified landscape-scale dispersion patterns for 30 species during fall and spring migration. Species differed in degree of dispersion, and in some cases, in their distribution on the landscape between spring and fall. Interspecific dispersion differences may arise from spatial constraints (habitat preference or specialization), or temporal constraints (migration distance), since availability and number of sites differs with habitat type, and time available for migration varies with distance traveled. Overall, we identified several types of migration strategies that relate to conservation and management: a) Consistently highly aggregated species, b) consistently dispersed species, and c) species that exhibit inconsistent dispersion patterns. Our results suggest that 1) broader management strategies are needed to effectively protect migratory shorebirds; 2) consideration of spatial dispersion may assist in setting broader conservation goals; and 3) for hotspots that have already been identified, knowledge of the landscape-scale dispersion patterns of species using that site could help managers to rank the importance of that site to many species, and to evaluate it within a continental context.

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This abstract is being presented at: 3:15 PM in session:
Oral Session #14: Disturbance Effects on Bird Populations.