Effects of landscape modification on biodiversity patterns and processes

景观的时空异质性在当地群落、种群和元群落的水平上塑造多样性格局，即通过扩散联系在一起的当地群落的区域集合：(1)立地条件和干扰的差异造成当地植物群落的镶嵌，这些镶嵌在支配其物种组成和多样性的主导过程中不同；(2)类似生境类型斑块的空间配置以及中间生境类型的性质(基质质量)影响扩散和基因流动，对遗传多样性和种群持久性产生重要影响；(3)斑块大小和空间隔离影响迁徙和灭绝速度，对当地和区域多样性之间的关系产生影响。这些效应很少在景观规模的实验中得到测试，因为通常没有大片实验区，实验操作将非常昂贵，需要运行多年才能显示假设的长期影响。1989年建立了一个实用的景观连通性项目，通过改善废弃地点(例如，移除木本植物)和通过轮牧绵羊重新连接地点来连接和维护石灰质干燥草原。我和我的实验室将重复广泛的基线植被调查(20年后)，并将它们与模拟建模、分子遗传学、空间分析和物种多样性尺度相结合，以解决三个主要问题：(1)立地管理的变化是否导致空间群落结构的差异，表明植物功能群组成和种间相互作用的变化？(2)生境配置和传播载体的变化是否导致植物基因流动模式的变化(花粉和种子传播)？以及(3)生境配置和传播载体的变化是否导致植物定殖率的变化，对当地和区域物种多样性之间的关系产生可预见的影响？了解形成植物物种多样性格局的不同过程是如何相互作用的，将有助于预测人类景观修改的影响，并提高景观规模保护管理的有效性。

Landscape spatial and temporal heterogeneity shapes diversity patterns at the levels of local communities, populations, and metacommunities, i.e., regional sets of local communities linked by dispersal: (1) differences in site conditions and disturbance create a mosaic of local plant communities that vary in the dominant processes governing their species composition and diversity, (2) the spatial configuration of patches of similar habitat type as well as the nature of the intervening habitat types (matrix quality) affect dispersal and gene flow, with important effects on genetic diversity and population persistence, and (3) patch size and spatial isolation affect immigration and extinction rates, with consequences for the relationship between local and regional diversity. These effects have rarely been tested in landscape-scale experiments, as large experimental areas are generally not available, experimental manipulation would be very costly and would need to run for many years to show the hypothesized long-term effects. An applied landscape connectivity project was established in 1989 to connect and maintain calcareous dry grasslands by improving abandoned sites (e.g., removal of woody species) and re-connecting sites through rotational sheep grazing. My lab and I will repeat the extensive baseline vegetation surveys (after 20 years) and combine them with simulation modeling, molecular genetics, spatial analysis and scaling of species diversity, to address three main questions: (1) does a change in site management lead to differences in the spatial community structure indicating a change in plant functional group composition and inter-specific interactions?, (2) does a change in habitat configuration and dispersal vectors lead to a change in gene flow patterns of plants (both pollen and seed dispersal)?, and (3) does a change in habitat configuration and dispersal vectors lead to a change in colonization rates in plants, with predictable effects on the relationship between local and regional species diversity? Understanding how the different processes shaping plant species diversity patterns interact will help to predict the effects of human landscape modification and improve the effectiveness of landscape-scale conservation management.