湘中丘陵区自然景观异质性与稻田捕食性天敌保护及生态控害效能的相关性

为明确自然景观异质性与稻田捕食性天敌保护及生态控害效能的相关性，以湖南省湘潭市涟水河流域下游段为研究区域，选择自然条件下具有不同景观异质性的稻田，调查稻田捕食性天敌多样性并分析其控害效能。结果表明：在早稻期与晚稻期，高异质性景观稻田的捕食性天敌物种丰富度分别为26.13和18.88；捕食性天敌个体数量分别为253.96个/m²和75.58个/m²；低异质性景观稻田的捕食性天敌物种丰富度分别为25.00和18.25；捕食性天敌个体数量分别为302.50个/m²和59.04个/m²；在早稻期与晚稻期，高异质性景观稻田的物种丰富度益害比分别是低异质性景观稻田的1.33倍和1.01倍；捕食性天敌个体数量益害比分别是低异质性景观稻田的1.40倍和1.53倍。过低与过高的景观组成异质性稻田，捕食性天敌物种丰富度与个体数量值均较低。具有良好生境或斑块连通性的稻田的捕食性天敌个体数量、生态控害效能显著高于具较差生境或斑块连通性的稻田，在晚稻期具有良好生境或斑块连通性的稻田的物种丰富度显著高于具较差生境或斑块连通性的稻田。建议在强化稻田捕食性天敌的生态控害效能策略中，既要考虑适度的景观组成异质性，更应重视增加异质景观或生境斑块间的连通性，强化廊道连接，利于捕食性天敌迁移、避险与保存，以达到水稻害虫可持续生态控制的目的。

Correlations between the natural landscape heterogeneity and the conservation and ecological control efficiency of predatory natural enemies in rice fields in hilly regions of the central Hunan Province

In order to determine the correlation between the heterogeneity of natural landscapes and the conservation and ecological control efficiency of predatory natural enemies in rice fields, the lower reaches of the Lianshui River Basin in Xiangtan City, Hunan Province were selected as the study region. The rice fields with different degrees of landscape heterogeneity under natural conditions were studied; the diversity of predatory natural enemies in rice fields was investigated, and their pest control efficiency was analyzed. The results showed that the species richness of predatory natural enemies in the highly heterogeneous landscape rice field (HHL) were 26.13 and 18.88 in the early and late rice stages, and the number of individuals were 253.96/m² and 75.58/m², respectively. The species richness of predatory natural enemies in low-heterogeneity landscape rice field (LHL) was 25.00 and 18.25, and the number of individuals was 302.50/m² and 59.04/m² in the early and late rice stages, respectively. The predator-prey ratio in terms of species richness in HHL was 1.33 times and 1.01 times as much as that in LHL. The predator-prey ratio in terms of number of individuals in HHL was 1.40 times and 1.53 times as much as that in LHL in the early and late rice stages, respectively. The landscapes with too low or too high compositional heterogeneity were not conducive to the conservation of predatory natural enemies. Good patch connectivity was beneficial for maintaining predatory natural enemies and improving their ecological control efficiency. Too low or too high landscape compositional heterogeneity led to lower species richness and individual number of predatory natural enemies in rice fields. The study suggested that, for protecting predatory natural enemies in rice fields and strengthening their ecological pest control efficiency, not only the moderate compositional heterogeneity of landscape should be considered, but also more attention should be paid to the increase of the connectivity in landscape, habitat patches or enhanced corridor connections, which was conducive to the migration of predatory nature enemies and thus achieving the goal of sustainable ecological control of rice pests.