David A. Kaplan
Michael Osland
Yiyang Kang
2024
<ol class=""><li>Climate change is reshaping coastal wetlands worldwide, driving ecosystem shifts like mangrove poleward expansion into saltmarshes in tropical-temperate transitional zones. Though warming is recognized as the primary driver, a lack of detailed field studies limits our ability to predict mangrove responses to rapid climate warming.</li><li>Here, we characterized how mangroves vary across a temperature gradient at 18 sites along Florida's Gulf of Mexico coast (USA). We used minimum air temperature (<i>T</i><sub>min</sub>) derived from daily data from 1989 to 2021 as the independent variable and applied plot-based and synoptic approaches to quantify species-specific mangrove variation at community, population, and individual levels. We then used these results to spatially project future mangrove ecosystem properties under multiple warming scenarios.</li><li>Across the<span> </span><i>T</i><sub>min</sub><span> </span>gradient from −10.8 to −1.4°C, mangrove canopy height and coverage ranged from 0.4 to 11.5 m and 15% to 98%, respectively, with both exhibiting sigmoidal increases with<span> </span><i>T</i><sub>min</sub>. Estimated mangrove aboveground biomass ranged from 0 to 496.7 Mg/ha and showed a positive linear relationship with<span> </span><i>T</i><sub>min</sub><span> </span>due both to the tall tree stratum's increased biomass per tree and higher abundance.</li><li>While the population abundance and coverage of<span> </span><i>Rhizophora mangle</i><span> </span>and<span> </span><i>Laguncularia racemosa</i><span> </span>had positive linear relationships with<span> </span><i>T</i><sub>min</sub>,<span> </span><i>Avicennia germinans</i><span> </span>exhibited a significant quadratic relationship, reflecting the higher freeze tolerance of this species. Such tolerance may stem from<span> </span><i>A. germinans</i>' higher morphological plasticity observed at the individual level, adapting to cold stress by exhibiting a more shrub-like architecture at colder sites.</li><li>Based on these field-derived quantitative relationships, we projected substantial increases in mangrove coverage and canopy height near current range limits, with tall<span> </span><i>A. germinans</i><span> </span>dominating in the north and<span> </span><i>R. mangle</i><span> </span>dominating the centre and south of the study region.</li><li><i>Synthesis.</i><span> </span>To better predict the ecological consequences in coastal wetlands under future climate change, it is essential to understand how mangroves respond to winter temperature regimes across a temperature gradient. Collectively, these cross-level and species-specific results advance our understanding of mangrove temperature sensitivity and provide information about the future of coastal wetland structure and function in response to a changing climate.</li></ol>
application/pdf
10.1111/1365-2745.14296
en
British Ecological Society
Linking temperature sensitivity of mangrove communities, populations and individuals across a tropical-temperate transitional zone
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