Limiting similarity mediates plant community niche hypervolume across a desert-steppe ecotone of Inner Mongolia
Limiting similarity mediates plant community niche hypervolume across a desert-steppe ecotone of Inner Mongolia
复制标题
有限的相似性介导内蒙古荒漠草原交错带植物群落生态位超体积
DOI：
10.1016/j.envexpbot.2018.06.011
复制
发表时间：
2018-09-01
影响因子：
5.7
通讯作者：
Smith, Melinda D.
中科院分区：
文献类型：
--
作者：
Mao, Wei;Zhao, Xueyong;Smith, Melinda D.
基于对多种资源利用特征的评估来量化生态位空间占用，可以提高对不同资源可用性社区内植物物种共存的理解。我们使用了一个“占据功能生态位空间（OFS）”的方法，根据多个叶片性状，研究植物群落如何适应水的可用性变化在沙漠草原交错带跨越有限的地理区域。我们的研究区域（内蒙古西部）跨越了一系列的条件，从高度水限制（沙漠，D），以较少的水限制（沙漠草原，S），与两个地区捕获这两种植被类型之间的生态区边界-部分沙漠（PD）和部分沙漠草原（PS）。我们测试了环境过滤，异质性，或限制相似性驱动性状收敛与分歧的OFS在沙漠草原交错带。我们量化了功能（比叶面积和叶干物质含量）和化学计量（叶氮含量和叶碳浓度）叶性状的植物群落加权平均值的变化。生态交错区（pS和pD）的OFS体积大于最中间（S）亚区。然而，相对于其他三个次区域，最干旱（D）次区域的OFS中心的差异很明显。OFS的潜在变化是植物功能类型的变化，在D中发现了更多的功能基团，而在S中发现的功能基团最少。群落加权叶片的比叶面积在群落交错区（pD和pS）最高，而在群落交错区（D）最低。此外，基于叶片干物质含量的群落加权平均值在D中是所有亚区中最高的，而基于叶片氮含量的群落加权平均值和基于叶片干物质含量的群落加权平均值都随着降水量的减少而减少，与预期一致。我们的研究结果表明，社区改变功能性状空间的体积和重心，以适应水资源的可用性下降。我们认为，限制相似性（即竞争性排斥）的物种之间的水资源利用性状，生活史的变化，导致OFS的生态区（PS和PD）和D的分歧，而环境过滤可能导致收敛的OFS最mesic区域（S）的水压力的教训。总的来说，我们的研究结果有助于了解植物群落如何在气候梯度上改变资源获取的性状空间，并强调了多性状方法在理解物种共存模式以应对气候变化方面的实用性。
Quantifying niche space occupation based on assessments of multiple resource utilization traits can improve an understanding of plant species coexistence within communities of varying resource availability. We used an 'occupied functional niche space (OFS)' method based on multiple leaf traits to examine how plant communities accommodate changes in water availability within a desert-steppe ecotone spanning a limited geographic region. Our study area (western Inner Mongolia) spanned a range of conditions from highly water-limited (desert, D) to less water-limited (desert steppe, S), with two areas capturing the ecotonal boundary between these two vegetation types - partial desert (pD) and partial desert steppe (pS). We tested whether environmental filtering, heterogeneity, or limiting similarity drove trait convergence versus divergence of OFS across a desert-steppe ecotone. We quantified changes in plant community weighted means of both functional (specific leaf area and leaf dry matter content) and stoichiometric (leaf nitrogen content and leaf carbon concentration) leaf traits. OFS in the ecotonal areas (pS and pD) had larger volumes than the most mesic (S) subregion. However, divergence in the centroid of OFS was apparent for the driest (D) subregion, relative to the other three sub-regions. Underlying changes to OFS were changes in plant functional types, with more functional groups found in D and the fewest in S. For community-weighted leaf traits, SLA was highest in the ecotone area (pD and pS), while lowest in D. Further, community weighted means based on leaf dry matter content in D was the highest of all sub-regions, while both community weighted means based on leaf nitrogen content and community weighted means based on leaf dry matter content decreased as precipitation decreased, consistent with expectations. Our results suggest that communities alter both the volume and the centroid of functional trait space to adjust to decreasing water resource availability. We posit that limiting similarity (i.e. competitive exclusion) in water-resource use traits among species, supported by changes in life histories, led to OFS divergence in the ecotonal areas (pS and pD) and D, while environmental filtering may have led to convergence of OFS within the most mesic region (S) as water-stress lessons. In total, our results contribute knowledge as to how plant communities alter trait space in resource acquisition across climatic gradients, and underscores the utility of multi-trait approaches in understanding patterns of species coexistence in response to climatic changes.