SPECIES CO-OCCURRENCE PATTERNS OF ZOOPLANKTON IN A NEOTROPICAL FLOODPLAIN

In tropical floodplains such as the Pantanal, hydrological variation is a major driver of zooplankton distribution and species co-occurrence patterns. We investigated how seasonal shifts between flood and drought phases structure positive and negative species associations, and whether environmental variables mediate these patterns. Specifically, we tested whether rotifers and cladocerans co-occur more or less often than expected by chance and whether functional similarity shapes these associations. Co-occurrence patterns were estimated using probabilistic models, and their relationships with environmental gradients were assessed through multivariate analyses and latent-variable models. Overall, positive associations predominated, indicating that many species respond similarly to environmental conditions. During the flood, positive co-occurrences were concentrated among functionally similar species, consistent with environmental filtering. In contrast, drought conditions led to an increase in negative associations, particularly among functionally distinct species, suggesting stronger niche differentiation under hydrological isolation. Environmental gradients related to water quality were the main predictors of co-occurrence structure. Together, these results show that the alternation between flood and drought regulates the balance between environmental filtering and niche differentiation, shaping zooplankton coexistence through time and contributing to biodiversity maintenance in tropical wetlands.

Presentation Preference: Standard Oral (12 Minutes)

Primary Presenter: Érica Lima, Universidade Estadual de Maringá (erika22schmoeller@gmail.com)

Authors:

Érica Lima, Universidade Estadual de Maringá  (erika22schmoeller@gmail.com)

Andressa Souza-Silva, Universidade Estadual de Maringá  (andressacrysstine@gmail.com)

Claudia Bonecker, Universidade Estadual de Maringá  (claudiabonecker@gmail.com)