Beneath the canopy, beneath the ground: how surface microhabitats shape cave communities

Area of Science:

• Ecology
• Conservation Biology
• Biospeleology

Background:

• Caves are interconnected with surface ecosystems, relying on external inputs and conditions.
• Subterranean environments harbor unique communities influenced by surface habitats.
• Amazonian ferruginous hills face threats from mineral exploitation, endangering cave ecosystems.

Purpose of the Study:

• To investigate how vegetation cover and environmental variables affect surface and subterranean fauna distribution in Amazonian ferruginous hills.
• To identify key factors for guiding conservation strategies for cave-associated species.
• To understand the faunal overlap between surface and subterranean habitats in relation to environmental conditions.

Main Methods:

• Sampling of six caves and ten epigean transects around each, covering ombrophilous forest and canga.
• Recording of environmental structure variables for all transects.
• Analysis of vegetation structure, microclimate, species richness, and community composition differences between forest and canga.

Main Results:

• Significant differences in vegetation structure, microclimate, species richness, and community composition were found between forest and canga.
• Species similar to cave fauna were associated with forest leaf litter, especially near cave entrances.
• Leaf litter depth was a key factor for faunal overlap, providing stable microhabitats. Faunal similarity in canga was limited to specific favorable conditions.

Conclusions:

• Cave-dwelling species in Amazonian ferruginous systems also inhabit adjacent forest environments.
• Forest leaf litter depth is critical for maintaining faunal connectivity between surface and subterranean habitats.
• Conservation of adjacent forest ecosystems is paramount for protecting subterranean biodiversity in these regions.