Trait-mediated community assembly: distinguishing the signatures of biotic and abiotic filters
Trait-mediated community assembly: distinguishing the signatures of biotic and abiotic filters
复制标题
DOI：
10.1111/oik.03945
复制
发表时间：
2017-08-01
期刊：
影响因子：
3.4
通讯作者：
Gilbert, Benjamin
中科院分区：
文献类型：
--
作者：
Loughnan, Deirdre;Gilbert, Benjamin
遗传假说预测性状如何介导物种建立和群落组装。当生物或非生物环境有利于单一最佳表型时，新建立的个体的性状被预测为收敛，或更类似于居民，预先存在的社区，但当性状差异减少竞争相互作用时，被预测为发散。我们测试了这些竞争的假设，使用移植幼苗在一个老领域的环境，并评估了种间和种内移植性状变异的贡献社区水平的模式。使用土壤水分梯度和居民植物的去除，我们确定新建立的植物的性状收敛或偏离居民社区通过计算社区加权平均性状移植和居民社区。我们看到了环境和竞争驱动的特征变化的证据，这些变化导致了居民社区的特征趋同和差异，居民社区的特征反映了这两个驱动因素的综合影响。叶干物质含量（LDMC）的移植分歧的存在下的竞争，而株高和茎比密度（SSD）表现出相反的模式，收敛与居民社区在他们的存在。比叶面积（SLA）转移与竞争，但没有反映居民社区SLA。所有的移植性状的影响，土壤水分，往往在相互作用与竞争，表明收敛或分歧的强度是依非生物环境。种内差异移植性状之间的治疗是明显的四个性状中的三个;种内高度和SLA的趋势反映移植社区水平的趋势，而种内的SSD的变化是不同的社区水平的趋势。我们的研究表明，植物物种之间的竞争可能会导致新建立的植物性状与居民社区趋同，就像它选择性状分歧一样频繁。竞争的这些相反的影响表明，它在种内和物种水平的性状差异社区之间发挥着普遍的作用。
Conflicting hypotheses predict how traits mediate species establishment and community assembly. Traits of newly establishing individuals are predicted to converge, or be more similar to the resident, preexisting community, when the biotic or abiotic environment favors a single best phenotype, but are predicted to diverge when trait differences reduce competitive interactions. We tested these competing hypotheses using transplant seedlings in an old-field environment, and assessed the contribution of inter-and intra-specific transplant trait variation to community-level patterns. Using a soil moisture gradient and resident plant removals, we determined when traits of newly-establishing plants converge or diverge from the resident community by calculating community weighted mean traits for transplant and resident communities. We saw evidence of environmentally-and competitively-driven trait shifts that resulted in both trait convergence and divergence from the resident community, whose traits reflect the combined effects of both drivers. Leaf dry matter content (LDMC) of transplants diverged in the presence of competition, whereas plant height and stem-specific density (SSD) showed the opposite pattern, converging with the resident community in their presence. Specific leaf area (SLA) shifted with competition but did not reflect resident community SLA. All transplant traits were influenced by soil moisture, often in an interaction with competition, indicating that the strength of convergence or divergence is contingent on the abiotic environment. Intraspecific differences in transplant traits among treatments were evident in three of four traits; intraspecific height and SLA trends mirrored transplant community-level trends, whereas intraspecific shifts in SSD were distinct from community-level trends. Our study shows competition between plant species may cause traits of newly establishing plants to converge with the resident community, as frequently as it selects for trait divergence. These opposing effects of competition suggest that it plays a pervasive role in both intraspecific and species-level trait differences among communities.