Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau & Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China.
Department of Geography and Planning, University at Albany, State University of New York, Albany, NY 12222, USA.
Sci Total Environ. 2018 Dec 10;644:806-814. doi: 10.1016/j.scitotenv.2018.07.019. Epub 2018 Jul 11.
Intensive anthropogenic land-use causes habitat loss and landscape homogenization, which leads to the decrease of biodiversity and ecosystem degradation. Therefore, it is important to study the influence of landscape heterogeneity on biodiversity. In this study, vegetation surveys conducted at 53 sites in the Tabu River basin, located at the agro-pastoral ecotone of Inner Mongolia of China, revealed 146 species. Species diversity was evaluated at three scales: species richness within patches (alpha diversity), between patches (beta diversity) and at the landscape scale (gamma diversity). We analyzed landscape heterogeneity (LH) and its driving factors including environmental variables (LHDF, such as precipitation and altitude), environmental heterogeneity (LHDF) and human activities (LHDF). We used structural equation modeling (SEM) to evaluate the response of species richness to landscape heterogeneity at three scales and determined the relative contribution of driving factors in explaining species diversity at these scales. The results of the study are summarized as follows: 1) Alpha diversity was the dominant component of gamma diversity in the Tabu River basin in Inner Mongolia. 2) There is no significant correlation (P = 0.512) between alpha diversity and LH; with the increase of LH beta and gamma diversities showed hump-shaped relationships. 3) LHDF was the primary factor in maintaining alpha diversity, with heterogeneity of mean annual precipitation (MAP), temperature (MAT) and altitude (ALT) acting as three largest contributors. LHDF primarily contributed to the maintenance of beta diversity. 4) LHDF was the primary contributor to gamma diversity, and human activity exceeded threshold values for positive effects. Based on our findings we suggest liming agricultural use along the river to prevent reductions in species diversity.
集约化的人类土地利用导致生境丧失和景观同质化，从而导致生物多样性减少和生态系统退化。因此，研究景观异质性对生物多样性的影响非常重要。本研究对位于中国内蒙古农牧交错带的塔布河流域 53 个样点进行了植被调查，共记录到 146 种植物。在三个尺度上评估了物种多样性：斑块内的物种丰富度（α多样性）、斑块间的物种丰富度（β多样性）和景观尺度的物种丰富度（γ多样性）。我们分析了景观异质性（LH）及其驱动因素，包括环境变量（LHDF，如降水和海拔）、环境异质性（LHDF）和人类活动（LHDF）。我们使用结构方程模型（SEM）来评估物种丰富度对三个尺度的景观异质性的响应，并确定驱动因素在解释这些尺度上物种多样性方面的相对贡献。研究结果总结如下：1）在内蒙古塔布河流域，α多样性是γ多样性的主要组成部分。2）α多样性与 LH 之间没有显著的相关性（P=0.512）；随着 LH 的增加，β和γ多样性呈现出驼峰形关系。3）LHDF 是维持α多样性的主要因素，其中平均年降水量（MAP）、温度（MAT）和海拔（ALT）的异质性是三个最大的贡献者。LHDF 主要有助于维持β多样性。4）LHDF 是γ多样性的主要贡献者，人类活动超过了积极影响的阈值。根据我们的发现，我们建议对河流沿岸的农业用地进行石灰处理，以防止物种多样性减少。
