Department of Biology, University of York, York, United Kingdom.
Leverhulme Centre for Anthropocene Biodiversity, University of York, York, United Kingdom.
PLoS One. 2024 Jul 29;19(7):e0307964. doi: 10.1371/journal.pone.0307964. eCollection 2024.
Surface freshwater is a vital resource that is declining globally, predominantly due to climate and land use changes. Cambodia is no exception and the loss threatens many species, such as the giant ibis a Critically Endangered waterbird. We aimed to quantify the spatial and temporal (2000-2020) change of surface water availability across northern and eastern Cambodia and to assess the impact of this on the giant ibis. We used a Random Forest Classifier to determine the changes and we tested the impact of land use and geographical covariates using spatially explicit regression models. We found an overall reduction of surface water availability of 4.16%. This was predominantly driven by the presence of Economic Land Concessions and roads which increased the probability of extreme drying and flooding events. The presence of protected areas reduced these probabilities. We found changes in precipitation patterns over the wider landscape did not correlate with changes in surface water availability, supporting the overriding influence of land use change. 98% of giant ibis nests recorded during the time period were found within 25m of surface water during the dry season, highlighting their dependency on surface water. The overall surface water decline resulted in a 25% reduction in dry season suitable habitat for the giant ibis. Although absolute changes in surface water over the whole area were relatively small, the impact on the highest quality habitat for ibis is disproportionate and therefore threatens its populations. Defining the threats to such an endangered species is crucial for effective management.
地表淡水是一种至关重要的资源，在全球范围内正在减少，主要是由于气候变化和土地利用变化。柬埔寨也不例外，这种损失威胁到许多物种，如极度濒危的水鸟巨嘴鸟。我们旨在量化柬埔寨北部和东部地表水供应的时空（2000-2020 年）变化，并评估这对巨嘴鸟的影响。我们使用随机森林分类器来确定变化，并用空间显式回归模型测试土地利用和地理协变量的影响。我们发现地表水供应总体减少了 4.16%。这主要是由于经济土地特许权和道路的存在，增加了极端干旱和洪水事件的可能性。保护区的存在降低了这些可能性。我们发现，更广泛的景观上降水模式的变化与地表水供应的变化没有相关性，这支持了土地利用变化的主导影响。在记录期间，98%的巨嘴鸟巢都位于旱季地表水 25 米范围内，这突出表明它们对地表水的依赖。地表水的总体下降导致巨嘴鸟在旱季适宜栖息地减少了 25%。尽管整个地区地表水的绝对变化相对较小，但对巨嘴鸟最高质量栖息地的影响不成比例，因此威胁到其种群。确定对这种濒危物种的威胁对于有效管理至关重要。
