Factors affecting wetland connectivity for wintering semipalmated sandpipers (Calidris pusilla) in the Caribbean

Abstract

Wetland connectivity provides migratory shorebirds varying options to meet energy requirements to survive and complete their annual cycle. Multiple factors mediate movement and residency of spatially segregated wetlands. Information on these factors is lacking in the tropics, yet such information is invaluable for conservation design. The influence of seven biotic and abiotic factors on local movement and residency rates of Semipalmated Sandpipers (Calidris pusilla) among three major wetlands in southwestern Puerto Rico in 2013-2014 was assessed using multi-state models. The model with highest support (AICc wi= 0.78) indicated that weekly residency rates increased seasonally, and were positively influenced by bird abundance and the interaction of prey density and rainfall. Movement rates were negatively influenced by inter-wetland distance, which varied annually, ranging from 0.01 ± 0.004 to 0.33 ± 0.08. Age class (adult, juvenile), extent of shoreline habitat (km), and body condition (estimated percent fat) did not influence residency rates (95% CIs overlapped Betas). Our findings indicated that coastal wetlands in southwestern Puerto Rico were connected, pointing at the joint value of salt flats and mangroves for overwintering Semipalmated Sandpipers. Connectivity between different types of wetlands likely widens resource diversity, which is essential for coping with unpredictable environments. Additional work is needed to generalize our understanding of inter-wetland dynamics and their potential benefits to inform shorebird conservation strategies in the Caribbean.