Using the macroinvertebrates collected from mountain and lowland ecoregions in the southern basin of Wei River as indicators,we compared the differences in the composition of 29 macroinvertebrate trait categories and seven traits and functional diversity indices between the two ecoregions.The combination of the joint analysis of R (environmental × sites),L (species × sites),and Q (trait × species) (RLQ) and fourth-corner analysis methods was conducted to explore the relationships between macroinvertebrate trait composition and land use and physical and chemical variables.We then used a generalized linear model (GLM) to compare differences in the responses of macroinvertebrate traits and functional diversity to environmental variables at different spatial scales between the two ecoregions.Our results showed that 18of the 29biological traits and 6 of the 7 traits and functional diversity indices significantly differed between the two ecoregions.Macroinvertebrates with biological traits such as none and shelters of leaf parts or wood refuge,lightly sclerotized,well protected exoskeleton or external protection,herbivores,and predators preferred habitats in the mountain ecoregion,while biological traits with integumentary respiration,soft body,and collector-gatherers tended to frequently occur in the lowland ecoregion under higher intensity of human activities.All traits and functional diversity indices,except functional evenness,were significantly higher in the mountain ecoregion than in the lowland ecoregion,which demonstrated that environmental stressors significantly decreased the biological traits and functional diversity in lowland areas.The combination of RLQ and fourth-corner methods revealed that the traits demonstrated a predictable response of trait patterns along the environmental gradient.The GLM model predicted that the functional and trait diversity in mountain and lowland ecoregions could be explained by different environmental variables at different spatial scales,with catchment urban land use,water temperature,and total nitrogen explaining most variations within the biological traits and functional diversity in the mountain ecoregion;but with reach scale agriculture land use and average water depth mainly explaining the decrease of the functional diversity in the lowland ecoregion.%以我国中部渭河南部流域山区和平原生态区的底栖动物为研究对象,通过计算29个生物性状类别和7个功能多样性指数,比较了不同生态区的生物性状组成和功能与性状多样性指数差异性;应用综合RLQ和fourth-corner方法探索底栖动物生物性状组成与土地利用和理化变量的关系;通过广义线性模型(GLM)比较不同空间尺度环境变量对底栖动物功能与性状多样性指数影响的生态区差异性.研究发现,共18个底栖动物性状组成在山区和平原间存在显著差异性,其中具有无庇护所和以叶片为庇护所材料、外骨骼轻微骨化和骨化良好、草食性、捕食性等生物性状的底栖动物栖息于栖境状况较好的山区,体壁呼吸、虫体柔软、集食者等生物性状更多的集中在人类活动较严重的平原区.除了功能均匀度指数外,山区的性状和功能多样性指数均显著高于平原,说明平原环境干扰显著降低了底栖动物性状和功能多样性.综合RLQ和fourth-corner方法表明底栖动物生物性状对环境胁迫的响应存在可预测性.GLM模型结果表明,山区和平原生物性状和功能多样性指数受到不同空问尺度土地利用和理化环境变量的影响:流域尺度城镇用地、水温和TN含量是影响山区功能和性状多样性指数模型的重要环境变量,但平原区河段尺度农业用地面积百分比和平均水深是影响功能和性状多样性的主要因子.
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