松嫩草原植被和土壤特性对蝗虫多样性的影响机制

Grasshoppers are the major components of grassland ecosystem, grasshopper diversity could be regarded as biological indicator for monitoring and assessing the grassland ecosystem function. In order to study the temporal-spatial dynamics in grasshopper diversity and structure of grasshopper assemblages in the Songnen grassland, the plant and soil characteristic are researched through field investigation, monitoring and laboratory analysis. The following researches are conducted: (1) Effect of plant community characteristics, including community composition, structure, nutrition, production and diversity, on the grasshopper community composition, population dynamic, habitats,diversiy and diet composition. (2) Influence of soil physical-chemical properties (soil texture, temperature, bulk density, pH value, moisture content and salt concentration) on the grasshopper community composition, population dynamic, habitat, egg laying site selection, the number of eggs per capsule, spatial distribution of egg in soil and life of eggs. (3) The response of embryonic development, fertility and fitness of grasshopper to soil moisture, salt and temperature stress. Based on three-year research, we wish to reveal influencing mechanism of plant and soil characteristics on the temporal-spatial dynamic in grasshopper diversity and structure of grasshopper assemblages. The above study are supposed to understand mechanism of losing grasshopper diversity in grassland ecsosystem,meanwhile provide the scientific evidence for preserving and protecting biodiversity, effectively managing grasshopper population and maintaining grassland ecosystem health.

蝗虫是草原生态系统重要组分，其多样性对反映草原生态系统功能具有重要指示作用。针对松嫩草原蝗虫群落结构和多样性时空变异的驱动机制，从研究植物群落和土壤理化特性入手；通过野外调查/监测、原地模拟、室内分析等途径，研究：（1）植物组成、结构、养分、生产力和多样性等对蝗虫群落组成、结构、数量、栖境、多样性和食性组成的影响；（2）草原土壤质地、温度、容重、pH值、含水量和盐分等理化特性对蝗虫群落组成、数量、栖境、产卵位点、卵囊所含虫卵数目、虫卵在土壤中的空间分布以及生命力等的影响；（3）土壤水分、温度和盐分胁迫对虫卵胚胎发育、繁殖力和适合度的影响。以期通过三年的上述研究工作，揭示草原植被和土壤特性对蝗虫群落结构和多样性时空动态的影响机理。为深入了解蝗虫多样性维持与丧失机制，实现蝗虫多样性保育、蝗虫危害有效防控和草地生态系统健康维系提供科学依据。

地表节肢动物多样性对陆地生态系统具有重要指示作用。针对松嫩平原蝗虫和地表节肢动物群落结构和多样性时空变异的驱动机制，从研究植物群落和土壤理化特性对草地蝗虫群落特性影响入手，揭示了毒杂草侵入、不同草地退化演替阶段、退化草地恢复措施下植物组成、结构、养分、生产力对蝗虫群落特性的影响；比较了不同耕作措施和地埂植物影响下土壤理化特性对地表节肢动物群落组成、数量、功能群等的影响。主要结果如下：.毒杂草侵入显著降低草地物种丰富度和均匀度指数，植被群落高度和生物量明显增加；臭草侵入型草地土壤有机质和含水量最高，狼毒侵入型草地土壤紧实度和天然草地全Ｎ含量显著高于其他样地；毒杂草侵入影响蝗虫群落组成、降低物种多样性、改变物种相对多度。蝗虫群落数量因臭草侵入而降低、随狼毒和披针叶黄华侵入而增加。.退化草地恢复重建措施对土壤理化特性有明显影响。围栏、禁牧和毒杂草防除样地同层土壤容重显著低于对照重度退化草地。禁牧和围栏样地土壤有机质、全氮、全磷、有效氮和有效钾含量显著高于对照。退化草地不同恢复措施对蝗虫群落特性有较大影响。草地蝗虫丰富度和多样性指数，均以围栏和禁牧样地最高，重度退化最低。.所有耕作措施下鞘翅目和蜘蛛目类群相对多度最高，步甲科为黑土农田优势地表节肢动物类群。免耕样地节肢动物类群丰富度和多样性指数最高，少耕最低。除旋耕外，其他耕作地表节肢动物功能群均以捕食性为主。群落相似性指数分析表明，不同耕作措施间群落相似性不同，免耕与组合之间相似性较高，而平翻与组合之间较低。免耕样地具有较高节肢动物类群丰富度和捕食性动物类群, 有利于维持黑土农田地表节肢动物多样性。.地埂植物带在农田生态系统中对维护和保持生物多样性发挥重要作用。地埂带植物物种多样性远远高于对照耕作农田。且不同建群种地埂带的物种数也有显著差异。究其原因，主要与地埂不收化学杀虫剂和除草剂的干扰，地埂及其植物为地表节肢动物生存的栖息环境和食物来源。此外，地埂栖息了大量有益昆虫，这些昆虫是一些农田害虫的天敌，为今后开展利用地埂植物生物多样性作为害虫天敌，用于生物防治提供思路。