Roots Ben J, Lim Ruth, Fourie Stephanie A, Rodgers Essie M, Stout Emily J, Cronin-O'Reilly Sorcha, Tweedley James R
School of Environmental and Conservation Sciences, College of Environmental and Life Sciences, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia.
Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia.
Animals (Basel). 2025 Jun 1;15(11):1629. doi: 10.3390/ani15111629.
In some estuaries, low inflow and/or isolation from the ocean can result in evapoconcentration and hypersalinity (≥40 ppt). This can create osmoregulatory and energetic challenges for the faunal community, leading to reductions in diversity as more species pass their thresholds. As climate change is increasing the magnitude and duration of hypersaline conditions, we used benthic macroinvertebrate data from 12 estuaries across a Mediterranean climatic region (southwestern Australia) to assess the influence of salinity (0-122 ppt) on the invertebrate fauna. Taxa richness and diversity were highest in salinities between 0 and 39 ppt, peaking at salinities closest to seawater, while total density peaked at 40-49 ppt. Beyond 50 ppt, these measures declined significantly. Community composition changed markedly along the salinity gradient. In lower salinities, communities were diverse, comprising polychaetes, malacostracans, hexapods, ostracods, bivalves, and gastropods. However, in salinities ≥50 ppt, many taxa declined, leading to communities dominated by polychaetes (mainly spp.) and hexapods (mostly larval chironomids). At 90 ppt, only polychaetes and hexapods remained, and at ≥110 ppt, only the latter taxon persisted. This faunal shift towards insect dominance in hypersaline conditions mirrors observations in other Mediterranean and arid/semi-arid regions, with the resulting communities resembling saline wetlands or salt lakes. This loss of invertebrates can substantially impact ecosystem functioning and trophic pathways, and the findings of this study provide a basis for predicting how these communities will respond to increasing hypersalinity driven by climate change.
在一些河口，低流量和/或与海洋隔绝会导致蒸发浓缩和高盐度（≥40ppt）。这会给动物群落带来渗透调节和能量方面的挑战，随着更多物种超过其耐受阈值，导致多样性降低。由于气候变化正在增加高盐度条件的强度和持续时间，我们利用来自地中海气候区（澳大利亚西南部）12个河口的底栖大型无脊椎动物数据，评估盐度（0 - 122ppt）对无脊椎动物群落的影响。分类丰富度和多样性在盐度0至39ppt之间最高，在最接近海水的盐度时达到峰值，而总密度在40 - 49ppt时达到峰值。超过50ppt，这些指标显著下降。群落组成沿盐度梯度发生明显变化。在低盐度下，群落多样，包括多毛类、软甲亚纲动物、六足动物、介形纲动物、双壳类和腹足类。然而，在盐度≥50ppt时，许多分类群数量下降，导致群落以多毛类（主要是 属）和六足动物（大多是摇蚊幼虫）为主。在90ppt时，只剩下多毛类和六足动物，在≥110ppt时，只有后一个分类群存在。在高盐度条件下动物群落向昆虫主导的转变与其他地中海和干旱/半干旱地区的观察结果相似，由此产生的群落类似于盐碱湿地或盐湖。无脊椎动物的这种减少会对生态系统功能和营养途径产生重大影响，本研究结果为预测这些群落将如何应对气候变化导致的高盐度增加提供了依据。
