Data from: Land-use intensification effects on functional properties in tropical plant communities

There is consensus that plant biodiversity and ecosystem processes are negatively affected by land-use intensification (LUI), but at the same time there is empirical evidence that a large heterogeneity in the responses can be found. This heterogeneity is especially poorly understood in tropical ecosystems. We evaluated changes in community functional properties across five common land use types in the wet tropics with different land-use intensity: mature forest, logged forest, secondary forest, agricultural land, and pastureland, located in the lowlands of Bolivia. For the dominant plant species, we measured 12 functional response traits that are related to their life history, acquisition and conservation of resources, plant domestication and breeding. We used three single-trait metrics to describe community functional properties. Community abundance-weighted mean (CWM) traits values, coefficient of variation, and kurtosis of distribution. The CWM of all 12 traits clearly responded to LUI. Overall, we found that an increase in LUI resulted in communities dominated by plants with acquisitive leaf trait values. However, contrary to our expectations, secondary forests had more conservative trait values (i.e., lower specific leaf area) than mature-and logged forest, probably because they were dominated by palm species. Functional variation peaked at intermediate land use intensity (high coefficient of variation and low kurtosis), which included secondary forest but, unexpectedly, also agricultural land which is an intensely managed system. The high functional variation of these systems is due to a combination of how response traits (and species) are filtered out by biophysical filters and how management practices introduced a range of exotic species and their trait values into the local species pool. Our results showed that, at local scales and depending on prevailing environmental and management practices, LUI does not necessarily result in communities with more acquisitive trait values or with less functional variation. Instead of the widely expected negative impacts of LUI on plant diversity, we found varying responses of functional variation, with possible repercussions on many ecosystem services. These findings provide a background for actively mitigating negative effects of LUI while meeting the needs of local communities that rely mainly on provisioning ecosystem services for their livelihoods.学界普遍认为，土地利用集约化（land-use intensification, LUI）会对植物生物多样性与生态系统过程产生负面影响，但同时亦有实证研究表明，不同生态系统的响应存在显著异质性。这种异质性在热带生态系统中尤其难以被深入解析。 我们针对玻利维亚低地地区的5种常见土地利用类型（覆盖不同土地利用强度），评估了群落功能属性的变化：成熟林、采伐林、次生林、农用地与牧草地。针对优势植物物种，我们测定了12项与植物生活史、资源获取与保存、植物驯化及育种相关的功能响应性状。我们采用3种单性状指标描述群落功能属性：群落加权平均性状值（community abundance-weighted mean, CWM）、性状分布的变异系数与峰度。 全部12项性状的CWM均对LUI呈现出显著响应。总体而言，土地利用强度提升会导致群落被具有资源获取型叶片性状的植物所主导。但与我们的预期相悖的是，次生林的性状策略更为保守（即比叶面积（specific leaf area）更低），这可能是因为其优势类群为棕榈科植物。功能性状的变异程度在中等土地利用强度下达到峰值（表现为高变异系数与低峰度），这一区间涵盖次生林，但出乎意料的是还包括集约化管理的农用地系统。这类系统的高功能变异，源于生物物理过滤对响应性状（及物种）的筛选方式，以及管理措施引入的一系列外来物种及其性状对本地物种种库的补充。 我们的研究结果表明，在局域尺度上，结合当前的环境条件与管理实践，LUI未必会形成以资源获取型性状为主导的群落，也未必会降低功能性状变异。与学界广泛预期的LUI对植物多样性的负面影响不同，我们发现功能性状变异的响应存在多样性，这可能对诸多生态系统服务产生连锁效应。这些研究结果可为主动缓解LUI的负面影响提供理论依据，同时兼顾以供给型生态系统服务维系生计的本地社区的发展需求。