Palaeoclimatic suitability dynamics of woody plant assemblages in Mesoamerican seasonally dry tropical forests over the last 800 000 years

ABSTRACT Mesoamerican seasonally dry tropical forests (SDTFs) are floristically differentiated, spatially discontinuous and affected by Quaternary climatic change; yet, effects on long‐term suitability, refugial persistence and environmental connectivity remain unresolved. We assessed whether climatic oscillations over the last 800 ka altered the extent and connectivity of suitable SDTF areas more strongly than core position (areas of high climatic suitability). Climatic suitability was modelled for 103 woody plant species from 25 families and projected at 1‐ka intervals. Palaeoclimatic suitability dynamics, candidate refugia and connectivity were evaluated using continuous and binary multispecies consensus models. Maximum binary overlap remained high (89–94 models) across 22 representative palaeoclimatic time slices, while the main high‐suitability core persisted along the Pacific slope of western and southern Mexico. The Yucatán Peninsula and northern Central America showed temporal variation in suitability and continuity. Seven candidate refugial nuclei were identified, six forming a discontinuous Pacific chain and one in north‐eastern Yucatán. Connectivity analyses identified five sectors of potential environmental connectivity, the largest spanning the Balsas Basin–southern Mexico. No connection was detected between the Pacific and Gulf slopes, and northern Central America remained disconnected from Mexico. Quaternary climatic oscillations reconfigured the extent and spatial continuity of suitable environments while preserving persistent high‐suitability cores.