Environmental parameters that shape zooplankton diversity in coastal wetlands of the Valencian Community, Spain

Along the Valencian coastline, numerous coastal wetlands persist as remains of extensive alluvial plains that once dominated the region. Historically, many of these wetlands were drained due to human activity, accelerated by urban development along the Mediterranean coast. Despite this, several larger or strategically located wetlands have endured and are now under protection. These ecosystems encompass diverse aquatic habitats including marshes, springs, canals, and shallow lagoons that support a rich variety of organisms, notably zooplankton, that are essential to aquatic food webs. This research aims to study the diversity (α, β and γ) of zooplankton and to assess how environmental variables influence their composition and diversity. Seasonal samples of zooplankton and water were collected from multiple sites within six selected wetlands: Prat de Cabanes-Torreblanca, Marjal dels Moros, Albufera de Valencia, Marjal Pego-Oliva, Salinas de Santa Pola, and Hondo de Elche. Zooplankton species were identified and quantified, and richness and different diversity metrics were estimated: Shannon and inverse Simpson indices (to estimate α-diversity), local contribution to beta diversity -LCBD- (for β-diversity), and Chao index (for γ-diversity). Physicochemical parameters, nutrient levels, and pigment concentrations were also measured, and their influence on diversity metrics was evaluated through multiple linear regression. The findings indicated that key factors influencing structure and diversity of the zooplankton community included water conductivity, phosphate concentration, chlorophyll-a concentration, seasonal changes, and type of waterbody. Freshwater wetlands showed greater α and γ-diversity. The Albufera de Valencia sites showed a significantly higher contribution to beta diversity than other sampling sites during all seasons, reflecting consistently unique communities