Multiscale variation in the burrow typology and abundance of Ucides cordatus across Atlantic mangroves: effects of time, space, and climate

Understanding ecological processes across spatial and temporal scales is crucial for interpreting population dynamics and guiding conservation efforts. However, multiscale influences on decapod crustacean populations remain underexplored. We investigated the variability in Ucides cordatus burrow typologies across two protected Brazilian mangrove ecosystems: Juréia-Itatins Ecological Station (JIES) and Superagui National Park (SNP). Sampling involved 120 quadrats (5 × 5 m each), with five quadrats allocated to each mangrove zone (fringe and apicum) at both conservation units, during summer and winter seasons over three consecutive years (2016–2018). Generalised linear models tested the effects of year, season, site, and tidal zone on the abundance of five burrow types: SGL (single-opening), MLT (multi-opening), OPE (sum of SGL and MLT), CLO (closed), and ABD (abandoned). We observed marked interannual and seasonal variability, especially under climatic anomalies, along with spatial contrasts driven by tidal flooding patterns and microhabitat structure. Burrow types reflected distinct functional phases: SGL and MLT were linked to active behaviour and responded sharply to environmental variation; CLO was associated with reproduction or moulting; ABD indicated environmental stress or recolonisation. Fringe zones exhibited greater variability and reduced open burrow abundance under stressful conditions. Integrating burrow typologies with spatiotemporal factors proved an effective, non-invasive approach for detecting ecological shifts and assessing habitat quality. Our findings reinforce the role of U. cordatus as a bioindicator species and support the use of burrow-based metrics in the long-term monitoring and conservation of mangrove ecosystems facing increasing climatic and anthropogenic pressures.