Population structure and seasonal variation of the family Ardeidae in two Pantanos de Villa Wildlife Refuge lagoons: contributions to the management and conservation of the Ramsar wetland

Abstract

Coastal wetlands exhibit high environmental heterogeneity and are increasingly subjected to anthropogenic pressures that can alter hydrological dynamics and habitat structure, thereby affecting the composition and distribution of waterfowl communities. In Pantanos de Villa Wildlife Refuge, differences in hydrological conditions and vegetation cover between lagoons may influence the spatial and age-related distribution of species belonging to the Ardeidae family. In this study, we evaluated the population dynamics and seasonal variation of Ardeidae species in the Génesis and Marvilla lagoons during 2024, considering age structure, species richness, seasonal diversity and species composition under contrasting hydrological conditions. Five Ardeidae species were identified, with significant differences in community composition between the different lagoons (PERMANOVA, p < 0.05). The Génesis lagoon showed a higher representation of juveniles, particularly Nycticorax nycticorax and Ixobrychus exilis, associated with greater hydrological stability and emergent vegetation cover. In contrast, Marvilla lagoon was dominated by adults of the species Egretta thula and Egretta caerulea, associated with shallow habitats characterized by lower emergent vegetation cover and greater marine influence. IndVal and SIMPER analyses identified indicator species and revealed that the differentiation between the lagoons was mainly attributable to Egretta thula, Nycticorax nycticorax and Egretta caerulea. The results of the study highlight the importance of hydrological dynamics and habitat structure in shaping the Ardeidae community and contribute relevant information for the adaptive management and conservation of this Ramsar wetland.