When troglobites set the rules: How cave‐restricted species shape community responses in the richest tropical subterranean hotspot

Neotropical subterranean ecosystems remain poorly understood, particularly regarding the environmental factors structuring their communities and how these processes vary across spatial scales. Moreover, no previous study has examined how cave‐restricted species influence community responses to habitat attributes.

We investigated the drivers shaping invertebrate assemblages in the Água Clara Cave System (ACCS), Bahia, Brazil (the richest subterranean biodiversity hotspot in the tropics), using a multiscale analytical framework and assessing the role of troglobitic taxa. Invertebrates were sampled in 59 sectors (10 × 3 m) and 177 quadrats (1 × 1 m) distributed along ~9 km of four interconnected caves.

We recorded 6835 individuals representing 27 orders, at least 87 families and 129 species, including 30 troglobitic taxa. Species richness responded to different predictors across scales: at the microscale, richness increased with trophic resource diversity and declined with distance from the entrance; at the mesoscale, it was negatively associated with shelter availability and distance from the entrance. Beta diversity was high at both spatial scales and was consistently dominated by species turnover, with patterns associated with distance from the cave entrance, humidity, temperature, resource availability, shelter availability and substrate diversity.

After excluding troglobitic taxa, ecological patterns weakened substantially: richness responded only to distance from the entrance at the microscale and β‐diversity lost most environmental associations.

These findings show that microclimatic and trophic factors structure ACCS communities and that troglobitic taxa strongly mediate these responses. Preserving the environmental integrity and microclimatic stability of the system is essential for safeguarding this subterranean biodiversity hotspot.