基于物种分布模型分析环境因子对海州湾偶见种资源分布的影响

Analysis of the influence of environmental factors on the distribution of occasional species in the Haizhou Bay based on species distribution model

偶见种易受环境变化和人类活动等外界威胁,在生物多样性保护中具有重要参考价值,但由于其数据量较少、分析困难,目前对分布特征的研究较少,其分布与环境因子的关系尚待探究。本研究基于2013–2019年海州湾渔业资源调查数据,分析了凤鲚(Coilia mystus)、红狼牙虾虎鱼(Odontamblyopus rubicundus)和虻鲉(Erisphex pottii)3种海州湾偶见种资源分布与环境因子的关系,并比较了广义可加模型(GAM)和随机森林(RF)模型对其资源分布的拟合效果,采用交叉验证的方法对模型的预测性能进行了评价。结果显示,水深是影响春、秋季凤鲚和红狼牙虾虎鱼资源分布的最显著因子,而底层水温仅在秋季是影响虻鲉资源分布的最重要环境因子。凤鲚分布模型的方差解释率最高,其次为红狼牙虾虎鱼,虻鲉模型方差解释率最低。凤鲚、红狼牙虾虎鱼和虻鲉分布模型在春季方差解释率均低于秋季。交叉验证表明,3个物种预测结果的曲线下面积(AUC)值在0.70~0.85之间,仅秋季凤鲚的AUC值达到0.9;同时GAM预测结果的AUC值均大于RF模型,表明对于偶见种而言,GAM的预测性能优于RF模型。本研究为今后开展偶见种研究的模型选择提供了参考,对偶见种资源保护具有指导意义。

Occasional species are vulnerable to external threats such as environmental changes and human activities and have important values in biodiversity conservation.However,due to their limited availability of data and associated difficulties in statistical analysis,there are few studies on the spatial distribution and their relationships with environmental factors.In this study,based on the fishery resource surveys in the Haizhou Bay conducted from 2013 to 2019,we analyzed the relationships between the distribution and environmental factors for three occasional species,Coilia mystus,Odontamblyopus rubicundus and Erisphex pottii,using generalized additive model(GAM)and random forest(RF)model.The models were compared according to their goodness of fit and the predictive performances were evaluated using cross-validation.The results showed that depth was the most significant factor affecting the distribution of C.mystus and O.rubicundus in spring and autumn,the sea bottom temperature was the most important environmental factor influencing the distribution of E.pottii in autumn.The distribution model of C.mystus had the highest deviance explanation,followed by O.rubicundus,and E.pottii had the lowest deviance explanation.The deviance explanation by the distribution models of C.mystus,O.rubicundus and E.pottii were all lower in spring than in autumn.The cross-validation showed that the area under the curve(AUC)of the three species ranged from 0.70 to 0.85,and only the AUC of C.mystus reached 0.9 in autumn;meanwhile,the AUC of the GAM prediction results were larger than those of the RF model,indicating that the prediction performance of the GAM was better than that of the RF model for the occasional species.This study would provide a reference for the selection of models for future studies of occasional species,and have guiding significance for the conservation of the occasional species.