In response to warming winter air temperatures, freeze-sensitive mangrove forests are expected to expand at the expense of freeze-tolerant salt marshes. To better anticipate and prepare for mangrove range expansion, there is a need to advance understanding of the modulating role of microclimate. Here, we synthesized hypotheses regarding the effects of microclimatic variation on temperature gradients and mangrove freeze damage. Temperature data from the literature and from temperature loggers were used to quantify ecologically relevant temperature gradients. Then, literature-derived mangrove freeze damage data were used to quantify the ecological effects of these temperature gradients. Six microclimatic factors are described that produce air temperature gradients that modulate mangrove responses to winter temperature extremes: (1) distance from the ocean; (2) distance from wind buffers; (3) mangrove canopy cover; (4) height above the soil surface; (5) local slope concavity; and (6) tidal inundation. Variation in these factors produces local temperature differences that range from 2 to 14 degrees C, with concomitant effects on horizontal and vertical patterns of biological damage from freezing. Collectively, our results elucidate the influence of microclimate on spatial patterns of biological damage and mortality due to winter temperature extremes. As mangrove ranges expand in response to climate change, we anticipate that microclimatic variation will produce adverse environments where mangrove expansion is prohibited as well as expansion hot spots where mangroves are protected. Subsequent expansion into newly available habitat will occur from protection zones, and microclimatic gradients may even produce positive feedback cycles that ultimately accelerate the rate of range expansion in response to warming.
1.US Geol Survey, Wetland & Aquat Res Ctr, 700 Cajundome Blvd, Lafayette, LA 70506 USA 2.US Geol Survey, Hartmann Consulting Serv, Wetland & Aquat Res Ctr, 700 Cajundome Blvd, Lafayette, LA 70506 USA 3.Florida Int Univ, Dept Earth & Environm, 11200 SW 8th St,AHC 5 360, Miami, FL 33199 USA
Recommended Citation:
Osland, Michael J.,Hartmann, Arik M.,Day, Richard H.,et al. Microclimate Influences Mangrove Freeze Damage: Implications for Range Expansion in Response to Changing Macroclimate[J]. ESTUARIES AND COASTS,2019-01-01,42(4):1084-1096