Abstract Understanding habitat use during early life stages is essential for the conservation and management of marine benthic invertebrates. Holothurians (sea cucumbers) undergo a critical post-larval transition from planktonic to benthic life, during which habitat selection strongly influences recruitment success, survival, and population structure. This study investigated spatial and seasonal patterns in the diversity of post-larval Holothuroidea (Dendrochirotida) and evaluated the influence of environmental variables and substrate types on species occurrence along the northeastern Brazilian coast. Monthly sampling was conducted throughout 2023 at three coastal sites (Tambaba, Formosa, and Genipabu beaches), using standardized intertidal transects encompassing macroalgal, sandy, and rocky substrates. Species were identified based on calcareous ossicles, and biodiversity patterns were assessed using Hill numbers, Chao1 richness estimates, and beta diversity partitioning. Generalized linear models were applied to test the effects of seasonality and environmental variables on diversity metrics, while substrate associations were evaluated using contingency analyses. A total of 169 post-larval individuals belonging to 11 species and three families: Cucumariidae, Phyllophoridae, and Sclerodactylidae were recorded. All specimens occurred exclusively on macroalgal substrates, confirming their role as essential nursery habitats. Tambaba exhibited the highest alpha and gamma diversity and a distinct species composition, whereas Formosa and Genipabu represented assemblages associated with strong abundance gradients relative to the richer Tambaba community. Species effective richness was positively associated with pH and negatively affected by the rainy season, indicating ontogenetic sensitivity to environmental variability. These findings highlight macroalgal beds as critical habitats for early holothurian life stages and underscore the importance of protected coastal areas for maintaining benthic biodiversity and supporting population resilience.
Stevenson et al. (Tue,) studied this question.