不同生态修复措施和环境因素对亚热带红壤区针叶纯林坡面水土保持功能的影响

Abstract

使用"地理探测器（GeoDetector）"对亚热带红壤区水土流失影响因素的定量分析结果可为当地森林生态修复和侵蚀模型完善提供科学依据。基于福建省龙岩市新罗区龙门溪小流域森林调查数据和径流小区监测数据，利用地理探测器探测不同生态修复措施和环境因素对针叶纯林坡面水土保持功能的影响及交互作用，结果表明：（1）对比中幼龄针叶纯林，补植阔叶树使针阔混交比例为7 ： 2可减少46%的径流量和76%的泥沙量，生态修复效果较好。对重侵蚀区"老头树"少量施肥难以产生效果。（2）影响坡面径流的因素由强到弱依次是：降雨因子（0.53），土壤容重、林分密度、灌草层盖度、树高和针阔比（均在0.08左右）；影响泥沙流失的因素依次是：地表径流量（0.84），降雨因子（0.2），林分密度、土壤容重、灌草层盖度、土壤含水率、灌草层生物量（均在0.12左右）。（3）各影响因素交互后主要呈增强作用；林分密度、灌草层盖度和土壤容重还可与其他因子产生强烈非线性增强作用（交互后影响力>0.9），是在森林修复和模型参数优化时需重点关注的对象。;The quantification results of the GeoDetector for the impact factors of the soil and water loss in the subtropical red soil area provide the scientific base for the local forest ecological restoration and the improvement of erosion models. This study explored the direct and interactive influences of different ecological restoration measures and environmental factors on water and soil conservation of the slope in forest by introducing the GeoDetector and using the forest survey data and the observation data of the runoff plots in Longmen Creek Watershed, Xinluo District, Longyan City, Fujian Province. The results showed that:(1) to compared with the middle and young age pure coniferous forest, the mixed conifer-broadleaf forest with the mixed ratio 7:2 could cut down the runoff and sediment load by 46% and 76%, respectively which represented that the ecological restoration effect of this measure was excellent. The small amount of fertilization hardly worked on the old tree in the heavy erosion area. (2) The rank of the strong impact factors of the runoff of the slope was rainfall (q value was 0.5), soil bulk density, stand density, shrub coverage, tree height and forest mixed ratio (q values were around 0.08). The rank of the strong impact factors of the sediment loads was surface runoff (q value was 0.84), rainfall (q value was 0.2), stand density, soil bulk density, shrub coverage, soil moisture content, total biomass of shrub (q values were around 0.12). (3) There were complex interactions among the factors of soil and water conservation function. The enhance effect mode accounted for most of the total pairs of the interactions between two factors. The interaction between the weak factors (such as stand density, shrub coverage, and soil bulk density, etc.) and other factors could result in the nonlinear enhancement, and the influence was greater than 0.9. Therefore, they should be paid more attentions when we performed the forest restoration and model parameter optimization.