Are artificial agricultural ponds a suitable alternative nesting habitat for the Little Ringed Plover?

Abstract

Climatic scenarios for the Mediterranean predict an increase in drought and erratic precipitation, which may affect waterbirds breeding in freshwater habitats. Artificial wetlands may provide an alternative for these species when conditions in natural habitats deteriorate. We studied Little Ringed Plovers Charadrius dubius nesting in natural streams and agricultural ponds in southern Portugal. Based on 24 nests and 31 colour-ringed adults, we describe nest-site characteristics, breeding parameters and site fidelity. In streams, nests (n = 17) were in sites with more abundant and coarser gravel, while in ponds there was more vegetation around the nest (n = 7). In both habitats, nests were close and at similar distances to water, but this was unrelated to nest outcome (success of 30.8% across habitats). Nest failure in natural streams was mostly attributable to flooding after heavy rains, while in agricultural ponds cattle trampling was the main cause of failure. Based on their renesting capacity and relatively high breeding site fidelity (25%–36% return rate to same area), we suggest that Little Ringed Plovers may trade-off the overall better conditions of natural streams (i.e. higher availability of nesting substrate, food resources and lower disturbance from cattle) against the stochastic risk of floods. Nevertheless, under current predictions of climate change, agricultural ponds can provide more stable and reliable nesting conditions for this and other species, as unpredictable changes in Mediterranean streams’ flooding regimen may become more frequent. Despite the limitations of our dataset, we provide novel information on the breeding biology of this understudied species and highlight its potential for future research.