Mao Wei, Felton Andrew J, Zhang Tonghui
Northwest Institute of Eco-Environment and Resource, Chinese Academy of SciencesLanzhou, China; Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort CollinsCO, USA.
Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins CO, USA.
Front Plant Sci. 2017 Mar 14;8:339. doi: 10.3389/fpls.2017.00339. eCollection 2017.
In recent years, both the intraspecific and interspecific functional diversity (FD) of plant communities have been studied with new approaches to improve an understanding about the mechanisms underlying plant species coexistence. Yet, little is known about how global change drivers will impact intraspecific FD and trait overlap among species, and in particular how this may scale to impacts on community level FD and ecosystem functioning. To address this uncertainty, we assessed the direct and indirect responses of specific leaf area (SLA) among both dominant annual and subordinate perennial species to the independent and interactive effects of nitrogen and snow addition within the Inner Mongnolian steppe. More specifically, we investigated the consequences for these responses on plant community FD, trait overlap and biomass. Nitrogen addition increased the biomass of the dominant annual species and as a result increased total community biomass. This occurred despite concurrent decreases in the biomass of subordinate perennial species. Nitrogen addition also increased intraspecific FD and trait overlap of both annual species and perennial species, and consequently increased the degree of trait overlap in SLA at the community level. However, snow addition did not significantly impact intraspecific FD and trait overlap of SLA for perennial species, but increased intraspecific FD and trait overlap of annual species, of which scaled to changes in community level FD. We found that the responses of the dominant annual species to nitrogen and snow additions were generally more sensitive than the subordinate perennial species within the inner Mongolian grassland communities of our study. As a consequence of this sensitivity, the responses of the dominant species largely drove impacts to community FD, trait overlap and community biomass. In total, our study demonstrates that the responses of dominant species in a community to environmental change may drive the initial trajectories of change to community FD and functioning.
近年来，植物群落的种内和种间功能多样性（FD）都已通过新方法进行研究，以增进对植物物种共存潜在机制的理解。然而，对于全球变化驱动因素将如何影响种内功能多样性和物种间的性状重叠，尤其是这如何扩展到对群落水平功能多样性和生态系统功能的影响，我们知之甚少。为了解决这种不确定性，我们评估了内蒙古草原上优势一年生植物和从属多年生植物的比叶面积（SLA）对氮添加和积雪添加的独立及交互作用的直接和间接响应。更具体地说，我们研究了这些响应对植物群落功能多样性、性状重叠和生物量的影响。氮添加增加了优势一年生植物的生物量，结果增加了群落总生物量。尽管从属多年生植物的生物量同时减少，但这种情况仍发生了。氮添加还增加了一年生植物和多年生植物的种内功能多样性和性状重叠，因此增加了群落水平上比叶面积的性状重叠程度。然而，积雪添加对多年生植物的种内功能多样性和比叶面积的性状重叠没有显著影响，但增加了一年生植物的种内功能多样性和性状重叠，这扩展到了群落水平功能多样性的变化。我们发现，在我们研究的内蒙古草原群落中，优势一年生植物对氮添加和积雪添加的响应通常比从属多年生植物更敏感。由于这种敏感性，优势物种的响应在很大程度上驱动了对群落功能多样性、性状重叠和群落生物量的影响。总体而言，我们的研究表明，群落中优势物种对环境变化的响应可能驱动群落功能多样性和功能变化的初始轨迹。
