Warmer Temperature and Spatiotemporal Dynamics during Primary Succession on Tropical Coastal Dunes

Coastal dunes are sensitive indicators of climate change: it is expected that higher precipitation and warmer temperature will promote vegetation growth and sand stabilization. Alternatively, dunes may become active during severe droughts, which would reduce plant cover and increase sand mobility. Consequently, it is relevant to explore community shifts and self-organization processes to better understand how coastal dunes vegetation will respond to these projected changes. Primary succession allows the exploration of community assembly and reorganization processes. We focused on three environmental variables (bare sand, temperature, and precipitation) and five successional groups (facilitators, colonizers, sand binders, nucleators, and competitors). For 25 years (from 1991 to 2016), species turnover was monitored in 150 permanent plots (4 x 4 m) placed on an initially mobile dune system located on the coast of the Gulf of Mexico. The spatiotemporal dynamics observed during primary succession were consistent with the facilitation nucleation model. As late colonizers grew and expanded, psammophytes became locally extinct. The spatial patterns revealed that ecological succession did not occur evenly on the dunes. In addition, the increased mean yearly temperature during the last decades seemed to be associated with the accelerated increment in plant cover and species richness, which had not been registered before in Mexico.

Automated summary

Coastal dunes serve as sensitive indicators of climate change, and understanding how vegetation in these dunes responds to projected changes is crucial. Primary succession plays a significant role in community assembly and reorganization processes. Studying the spatiotemporal dynamics of primary succession in a dune system on the Gulf of Mexico coast revealed that late colonizers grew and expanded, leading to the local extinction of psammophytes. The study also identified an association between increased temperatures and enhanced plant cover and species richness, which was previously undocumented in Mexico.