Files for "Environmental Determinants of Phylogenetic Diversity in Vernal Pool Habitats"

Phylogenetic diversity offers critical insights into the ecological dynamics shaping species composition and ecosystem function, thereby informing conservation strategies. Despite its recognized importance in ecosystem management, the assessment of phylogenetic diversity in endangered habitats, such as vernal pools, remains limited. Vernal pools, characterized by cyclical inundation and unique plant communities, present an ideal system for investigating the interplay between ecological factors and phylogenetic structure. This study aims to characterize the phylogenetic patterns of vernal pools and their associated vegetation zones, addressing questions about taxonomic and phylogenetic community discreteness, the role of flooding as a habitat filter, the influence of invasive species on phylogenetic structure, and the impact of seasonal variation on phylogenetic diversity. I find that zones-of-vegetation exhibit high between zone taxonomic and phylogenetic beta diversity whereas each zone forms a unique cluster, suggesting that zones are taxonomically and phylogenetically discrete units. Regions of high inundation pressure exhibit phylogenetic clustering, indicating that flooding is a habitat filter in vernal pool habitats. Competition between native species conform to the ‘competitive relatedness hypothesis’ and, conversely, communities dominated by invasive Eurasian grass species are phylogenetically clustered. In addition, I find that phylogenetic diversity within zones fluctuates across the spring season in response to changing water levels, precipitation, and temperature. By analyzing three pools within the Merced Vernal Pool and Grassland Reserve, this research elucidates the phylogenetic dynamics of vernal pools. The findings underscore the need for tailored conservation strategies that account for the unique ecological characteristics of each vegetation zone within vernal pool habitats.

系统发育多样性（phylogenetic diversity）可为塑造物种组成与生态系统功能的生态动态提供关键洞见，进而为保护策略制定提供依据。尽管其在生态系统管理中的重要性已得到公认，但针对濒危生境（如春季池（vernal pool））的系统发育多样性评估仍十分有限。春季池以周期性淹水与独特植物群落为特征，是探究生态因子与系统发育结构间相互作用的理想研究体系。本研究旨在刻画春季池及其伴生植被带的系统发育格局，解答如下问题：群落的分类学与系统发育离散性、淹水作为生境过滤（habitat filter）因子的作用、入侵物种对系统发育结构的影响，以及季节变化对系统发育多样性的效应。研究发现，各植被带间存在较高的分类学与系统发育β多样性（beta diversity），且每个植被带均形成独立的聚类簇，表明植被带在分类学与系统发育层面均为离散单元。淹水压力较高的区域呈现系统发育聚集特征，这表明淹水是春季池生境中的生境过滤因子。本土物种间的竞争符合“竞争亲缘关系假说（competitive relatedness hypothesis）”；与之相反，以入侵性欧亚草本植物为优势类群的群落则呈现系统发育聚集特征。此外，研究发现植被带内的系统发育多样性在春季随水位、降水量与温度的变化而波动。本研究通过对默塞德春季池与草原保护区（Merced Vernal Pool and Grassland Reserve）内三处春季池的分析，阐明了春季池的系统发育动态。本研究结果强调，需制定针对性保护策略，以兼顾春季池生境内各植被带的独特生态特征。