Environmental context modulates macrofauna mediated functioning and potential resilience of tropical marine protected...

Tropical Marine Protected Areas (MPAs) face growing threats from climate change and anthropogenic pressures. Abrupt environmental changes can disrupt core ecosystem functions, eroding the functional redundancy that underpins potential resilience. A comparative study of two contrasting Indian coralline MPAs, the Gulf of Kachchh (GoK) and the Gulf of Mannar (GoM), employing macrobenthic functional studies revealed variable resilience, modulated by the contrasting environmental contexts of the MPAs. Functional evenness and divergence were comparable between MPAs, whereas GoK exhibited higher functional dispersion and RaoQ. GoM supported higher proportion of sensitive functional modalities, while GoK showed greater representation of opportunistic modalities, consistent with differing environmental contexts. Sedimentological parameters structured trait distributions in both MPAs, with nutrients adding a region-specific influence in GoK, as revealed by RLQ and fourth-corner analyses. GoM exhibited comparatively higher functional redundancy, suggesting that multiple species may perform similar ecological roles and thereby helping to maintain ecosystem functioning even during species loss, which may indicate greater resilience. This elevated trait overlap is consistent with GoM's biologically rich environment and low environmental variability. In contrast, GoK is governed by intense evaporation, strong currents, high sedimentation and energetic semidiurnal tides. These hydrodynamically unstable and climate responsive conditions can reduce the potential resilience, rendering the GoK ecosystem more vulnerable to future climate perturbations. Integrating functional diversity indices provided critical insights into ecosystem resilience relevant to coral reef management and conservation. This study highlights that environmental context modulates potential resilience of MPAs, underscoring that protected status alone does not shield ecosystems from environmental pressures.