Halophytes can salinize soil when competing with glycophytes, intensifying effects of sea level rise in coastal communities
Halophytes can salinize soil when competing with glycophytes, intensifying effects of sea level rise in coastal communities
复制标题
盐生植物在与糖质植物竞争时会使土壤盐碱化，加剧海平面上升对沿海社区的影响
作者：
Kristie S. Wendelberger;J. Richards
海平面上升（SLR）和土地利用变化正在共同改变世界各地的沿海社区。沿着佛罗里达的海岸，SLR和大规模的干旱正在增加地下水的盐度，导致盐生植物（耐盐）物种定居在糖生植物（不耐盐）社区。我们假设，盐生植物可以有助于增加土壤盐分，因为他们进入glycophyte社区，使土壤比SLR或干燥更咸。我们测试了我们的假设，一系列的温室实验与盐生植物/糖生植物的比例为0：4，1：3，2：2，3：1，4：0，模仿盐生植物运动到糖生植物群落。我们进行了重复0，26，和38‰的盐度分别为1，1，和3个月，在每个处理期结束时，采取土壤盐分和气孔导度的测量。结果表明，土壤盐分随盐生/糖生植物比例的增加而增加。无论是渗透胁迫还是离子胁迫，都导致了盐生植物生物量的减少，从而导致了盐生植物蒸腾作用的减少。在38‰的地下水中，土壤盐分随着盐生植物密度的增加而增加，使得条件更有利于盐生植物的进一步建立。这项研究表明，沿海植物群落的周转可能会发生更快的速度比将从SLR和人为干扰单独预测。
Sea level rise (SLR) and land-use change are working together to change coastal communities around the world. Along Florida’s coast, SLR and large-scale drying are increasing groundwater salinity, resulting in halophytic (salt-tolerant) species colonizing glycophytic (salt-intolerant) communities. We hypothesized that halophytes can contribute to increased soil salinity as they move into glycophyte communities, making soils more saline than SLR or drying alone. We tested our hypothesis with a replacement-series greenhouse experiment with halophyte/glycophyte ratios of 0:4, 1:3, 2:2, 3:1, 4:0, mimicking halophyte movement into glycophyte communities. We subjected replicates to 0, 26, and 38‰ salinity for one, one, and three months, respectively, taking soil salinity and stomatal conductance measurements at the end of each treatment period. Our results showed that soil salinity increased as halophyte/glycophyte ratio increased. Either osmotic or ionic stress caused decreases in glycophyte biomass, resulting in less per-plant transpiration as compared to halophytes. At 38‰ groundwater, soil salinity increased as halophyte density increased, making conditions more conducive to further halophyte establishment. This study suggests that coastal plant community turnover may occur faster than would be predicted from SLR and anthropogenic disturbance alone.