Floods drive functional zooplankton diversity in a core area of the Brazilian Pantanal Biosphere Reserve

ABSTRACT

Water dynamics in floodplains are fundamental in structuring aquatic communities. Our research investigated zooplankton communities in the Pantanal ecosystem. Different hydroperiod phases can influence the functioning of aquatic ecosystems, but an understanding of the taxonomic and functional diversity of zooplankton in these areas is lacking. Over 3 years (2018–2020), we assessed the zooplankton community in habitats along the Paraguay River at the Taiamã Ecological Station, considering the flood, ebb, drought, and inundation phases. We used indices such as Rao’s quadratic entropy (RaoQ), functional evenness (FEve), functional divergence (FDiv), community weighted means (CWM), and fourth-corner RLQ to investigate the potential relationships between the taxonomic and functional diversity of zooplankton and the hydroperiod phases and limnological variables. We identified 153 species of zooplankton, with greater richness in the families Lecanidae and Brachionidae (rotifers) and Chydoridae and Daphnidae (cladocerans). Species composition varied significantly between flood and drought phases. We observed positive relationships between chlorophyll a, total nitrogen/phosphorus, and species with larger body size, pelagic habitat, filter-feeding mode, and medium predator evasion capacity, whereas littoral species and those with low predator evasion capacity showed negative relationships. CWM exhibited differences in functional traits between hydroperiod phases. FDiv analysis indicated well-defined ecological functions among the community species, and the low FEve value during the flood phase indicated the dominance of certain functional attributes. These results emphasize the relationship between hydrological processes and the distribution of zooplankton communities, highlighting the importance of functional diversity in understanding ecological interactions.

KEYWORDS:

• limnological variables
• plankton; taxonomic and functional classification
• wetlands

Acknowledgements

We thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for awarding the master’s scholarship, and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for the research productivity fellowship as part of the PELD/DARP – Long-Term Ecological Research Program/Dynamics of the Flood Pulse in the Sociocultural Ecological System of the Paraguay River within the Context of the Pantanal Biosphere Reserve, Mato Grosso, Brasil (contributions No. 39). We are grateful to the Universidade do Estado de Mato Grosso, the Graduate Program in Environmental Sciences, and the Pantanal Research Center in Limnology, Biodiversity, and Ethnobiology, as well as the Chico Mendes Institute for Biodiversity Conservation, for their field support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico: [Grant Number 23034.022102/2021-27]; Fundação de Amparo à Pesquisa do Estado de Mato Grosso: [Grant Number 0152640/2021].