管理措施及土壤因子对5种农田生境地表蜘蛛群落多样性的影响

Effects of management measures and soil factors on the diversity of ground spider communities in five agricultural habitat types

以往的研究表明有机管理有利于生物多样性保护,但在不同农业生境类型中是否都存在这个结论呢?基于此问题,本研究在一个多生境的有机管理农场与一个相邻的多生境常规集约化管理农区,采用陷阱法进行蜘蛛取样,对比有机和常规管理措施下大棚菜地、果园、稻田田埂、露天田块及农田边界等5种生境类型的农田蜘蛛多样性的差异,并分析土壤因子对蜘蛛多样性的影响。研究发现:1)有机管理与常规管理的蜘蛛物种数没有显著差异,但有机管理的果园中蜘蛛个体数比常规管理的果园中多139%,且差异显著。同一管理措施下,仅常规管理农田区的农田边界蜘蛛个体数和物种数分别显著高于其他生境均值104%和59%。2)有机管理农场比常规管理农田的蜘蛛物种组成差异略大,且在有机管理下不同生境间的蜘蛛群落组成差异更明显。3)土壤因子中有机质、全氮、全磷含量等对蜘蛛群落结构有显著影响,但对蜘蛛个体数和物种数没有显著影响,仅土壤Cu含量和蜘蛛个体数呈显著负相关。在本研究中虽然有机管理和土壤因子对蜘蛛多样性有一定影响,但不同生境间管理强度、植被结构等差异对蜘蛛多样性的影响更大。因此,发展多种农业生境类型的有机农业可提升物种β多样性。同时,在常规集约化管理农区,保留农田边界等半自然生境、适当减少化肥和农药等投入、降低农田内部的管理强度、防止土壤重金属污染等措施均有助于保护蜘蛛多样性。

Empirical studies have demonstrated the positive effects of organic management on farmland biodiversity,but the consistency of this effect between different agricultural habitat types has not been explored.Therefore,a comparison study was conducted between two adjacent farmlands,both with multiple habitats but subjected to contrasting management measures(organic vs.conventional).We sampled spiders using pitfall traps and examined differences in their diversity across organically and conventionally managed farmlands for five different habitat types(vegetable greenhouses,orchards,open-air fields,field margins,and paddy ridges).We also examined how the soil factors affect spider diversity.No significant differences were detected in species richness between the organically and conventionally managed farmlands,but spider abundance in the organically managed orchards was 139%higher than in the conventionally managed orchards.Within the same management system,spider abundance and species richness in the field margins of conventionally managed agricultural areas were 104%and 59%higher than in other habitats,respectively.The difference in spider community composition in organically managed farmland was slightly larger than in conventionally managed farmlands.Meanwhile,the difference in spider community composition between different habitat types was greater in organically managed farmlands than in conventionally managed farmlands.The organic matter content,total nitrogen,and total phosphorus in the soil significantly affected the spider community structure,but these factors did not correlate with spider abundance or species richness.There was a significant negative correlation between total copper(Cu)and spider abundance.This study showed that the spider community is affected by many factors.The management intensity of different habitat types and the vegetation structure were more important than management practices and soil factors.Thus,it is important to create different agricultural habitats and develop organic management techniques to sustain beta-diversity at the landscape scale.Maintaining semi-natural habitats(such as field margins with rich vegetation),reducing agrochemical inputs and disturbances on farmlands,and preventing soil heavy metal pollution may help sustain spider diversity in conventionally managed farmlands.