Multi-scale functional and taxonomic β-diversity of the macroinvertebrate communities in a Mediterranean coastal lagoon

Abstract

Benthic macroinvertebrate communities form the basis of the intricate lagoonal food web. Understanding their functional and taxonomic response, from a β-diversity perspective, is essential to disclose underlying patterns with potential applicability in conservation and management actions. Within the central lagoon of Messolonghi, we studied the main environmental components structuring the macroinvertebrate community. We analyzed the β-taxonomic and β-functional diversity across the main habitats and seasons, over a year time frame. Our results outline habitat type and vegetation biomass as the major factors structuring the communities. We found environmental variability to have a positive correlation with functional β-diversity; however, no correlation was found with taxonomic β-diversity. Across the seasons, an asynchronous response of the functional and taxonomic β-diversity was identified. The taxonomic composition displayed significant heterogeneity during the driest period and the functional composition during the rainy season. Across the habitats, the unvegetated ones presented higher taxonomic homogeneity and functional heterogeneity, contrary to the vegetated habitats that present higher taxonomic variability and functional homogeneity. Across the seasons and habitats, a pattern of functional redundancy and taxonomic replacement was identified. Moreover, high functional turnover versus low taxonomic turnover was documented in an anthropogenic organically enriched habitat. We conclude that habitats display independent functional and taxonomic seasonal patterns and, thus, different processes may contribute to their variability. The framework presented here highlights the importance of studying both β-diversity components framed in a multi-scale approach for a better understanding of ecological processes and variability patterns. These results are important for understanding macroinvertebrate community assembly processes and are valuable for conservation purposes.