基于Maxent模型的海地瓜（Acaudina molpadioides）区域适宜生境分布预测研究

生境适宜性预测对物种保护、外来生物及有害生物防治具有重要指导意义。本研究应用Maxent模型对宁德晴川湾海域海地瓜适宜性生境进行预测，模型的预测结果达到优秀水平，并结合ArcGIS软件对海地瓜适宜生境划分为5级。研究结果表明，极高和较高海地瓜适宜生境占总研究区域的1.3%，面积为25.6 km2。水体环境、沉积环境和生态群落均对海地瓜分布产生影响，水体环境中水深、盐度、无机氮和活性磷酸盐是影响海地瓜生境适宜性的主要水环境因子，对海地瓜适宜生境预测累计贡献率达39%，尤其水深是制约海地瓜分布最为主要的因子，预测贡献率为27%；沉积物粒度、硫化物和总有机碳是沉积环境主要影响因子，预测累计贡献率达40.4%，其中沉积物黏土颗粒体积占比是第二重要影响因子，预测贡献率约为18%。浮游动物密度和生物量以及底栖动物种类数量均对海地瓜分布产生一定影响，三者预测累计贡献率为16.8%，其中浮游动物密度的贡献相比其他生物要素最为重要，贡献率约为8%。总体上，海地瓜最为理想的分布区是近岸水深小于5 m、盐度相对较低、沉积物有机碳含量较高、底质为黏土?粉砂土为主的浅水淤泥质生境。

The potential suitability habitat prediction of Acaudina molpadioides based on Maxent model

The prediction of habitat suitability has important guiding significance for species protection, alien and pest control. In this study, Maxent model was used to predict the suitability habitat of A. molpadioides in Qingchuan Bay, Ningde, Fujian Province. The results of the model reached an excellent level. Combined with ArcGIS software, the suitable habitat of the A. molpadioides was divided into five grades. The results showed that: 1.3% of the total study area was highly suitable, and the area was 25.6 km2. Water environment, sedimentary environment and ecological community all had an impact on the distribution of the A. molpadioides. Water depth, salinity, inorganic nitrogen and active phosphate were the main factors of water environment. The cumulative contribution rate to the prediction of the suitable habitat of A. molpadioides was 39%, especially, the water depth was the most important factor that restricts the distribution of the A. molpadioides, the prediction contribution rate was 27%; sediment grain size, sulfide content and total organic carbon in surface sediment were the main factors of sedimentary environment, and the cumulative contribution rate was 40.4%. The second important factor was the volume percentage of substrate of sediment clay, and the contribution rate was about 18%. The density and biomass of zooplankton and the number of benthos all had a certain impact on the distribution of A. molpadioides, the cumulative contribution rate was 16.8%, among which the contribution rate of zooplankton density to other biological factors was the most important, about 8%. On the whole, the most ideal distribution area of A. molpadioides is the shallow water muddy bottom habitat, where the water depth is less than 5 m, the salinity is relatively low, the organic carbon content of sediment is relatively high, and the bottom material is mainly clay silt.