Miller Jesse E D, Damschen Ellen I, Harrison Susan P, Grace James B
Ecology. 2015 Dec;96(12):3323-31. doi: 10.1890/15-0245.1.
Understanding how biotic communities respond to landscape spatial structure is critically important for conservation management as natural habitats become increasingly fragmented. However, empirical studies of the effects of spatial structure on plant species richness have found inconsistent results, suggesting that more comprehensive approaches are needed. We asked how landscape structure affects total plant species richness and the richness of a guild of specialized plants in a multivariate context. We sampled herbaceous plant communities at 56 dolomite glades (insular, fire-adapted grasslands) across the Missouri Ozarks, USA, and used structural equation modeling (SEM) to analyze the relative importance of landscape structure, soil resource availability, and fire history for plant communities. We found that landscape spatial structure, defined as the area-weighted proximity of glade habitat surrounding study sites (proximity index), had a significant effect on total plant species richness, but only after we controlled for environmental covariates. Richness of specialist species, but not generalists, was positively related to landscape spatial structure. Our results highlight that local environmental filters must be considered to understand the influence of landscape structure on communities and that unique species guilds may respond differently to landscape structure than the community as a whole. These findings suggest that both local environment and landscape context should be considered when developing management strategies for species of conservation concern in fragmented habitats.
随着自然栖息地日益碎片化，了解生物群落如何响应景观空间结构对于保护管理至关重要。然而，关于空间结构对植物物种丰富度影响的实证研究结果并不一致，这表明需要更全面的方法。我们研究了在多变量背景下景观结构如何影响植物总物种丰富度以及一个特殊植物类群的丰富度。我们在美国密苏里州欧扎克地区的56个白云石浅滩（岛屿状、适应火灾的草原）对草本植物群落进行了采样，并使用结构方程模型（SEM）分析景观结构、土壤资源可用性和火灾历史对植物群落的相对重要性。我们发现，景观空间结构定义为研究地点周围浅滩栖息地的面积加权接近度（接近指数），对植物总物种丰富度有显著影响，但前提是我们控制了环境协变量。 specialist物种（而非generalist物种）的丰富度与景观空间结构呈正相关。我们的结果强调，必须考虑当地环境筛选因素，以了解景观结构对群落的影响，并且独特的物种类群对景观结构的响应可能与整个群落不同。这些发现表明，在为碎片化栖息地中受保护的物种制定管理策略时，应同时考虑当地环境和景观背景。
