Spatial Synchrony of Diving Waterbirds Populations in Continental Wetlands of the Iberian Region

Spatial population synchrony is a key aspect in ecology. Normally, three mechanisms have been identified to explain similar temporal variations in abundance between spatially separated populations: Moran effect, trophic interactions and dispersal. We analysed the spatial synchrony of the abundance of five diving waterfowl species (White-Headed Duck, Black-Necked Grebe, Red-Crested Pochard, Common Pochard and Common Coot) by conducting a monthly census from October 2013 to September 2019 in 34 lakes located in Central Spain. Twenty-eight independent variables related to the hydroperiod, anthropogenic impacts, landscape and structural variables were tested in relation to temporal patterns. Synchronised lakes groups were identified for all species, with differential associations with variables. The variables associated with spatial synchrony were: Distance between lakes (White-Headed Duck and Common Pochard); Natural vegetation area in lakes (Red-Crested Pochard) and Accumulated precipitation until the breeding season (Common Pochard and Common Coot). For Black-Necked Grebe, no variable was associated with the observed temporal patterns. These results provide the first evidence for the mechanisms behind the spatio-temporal synchronisation of diving waterbirds populations in the central Iberian region.