中国被子植物性系统空间格局及其形成机制

Sexual systems play an important role in angiosperm evolution, community assembly, and species responses to climate change, further influencing the level of biodiversity. Selective pressures on sexual expression vary with environmental conditions, potentially leading to geographical variations in the composition of sexual systems in different local floras. Previous studies have found that environmental selection, life-history traits, and evolutionary history could influence sexual system expression and therefore geographical variations of sexual systems. However, the pattern of sexual systems variation across environmental gradients at large biogeographic scales and the relative contribution of abiotic and biotic drivers (climate, life-history traits and evolutionary history) to the present-day biogeographical patterns of plant sexual systems remains poorly understood. Using data for sexual systems of angiosperms spanning a broad environmental gradient in China, along with high-resolution data on species distributions, we explored the geographical variation in sexual systems of angiosperms in China and their potential abiotic (climatic) and biotic (plant traits and evolutionary age) drivers. Specifically, we aim to answer the following three key questions:.1) What is the biogeographic pattern in the composition of angiosperm sexual systems across China?.2) How climate change, biotic traits and evolutionary history affect geographical variation in the prevalence of different sexual systems (dioecy, monoecy, and hermaphroditism), and what are their relative influences?.3) What are the similarity and differences of the biogeographical patterns and associated drivers of the sexual system composition of woody and herbaceous plants in China?.This project aims to enhance the understanding of the biodiversity patterns and driving forces and structural stability of forest ecosystems in China, and provide scientific support for the conservation of biodiversity and establishment of natural reserves.

被子植物性系统的空间分布格局及其对环境变异的生态响应是生态系统结构和功能稳定性维持必需明确的关键科学问题。以往关于被子植物性系统的研究多基于单个或若干个物种或是零散的空间分布数据，被子植物性系统的生物地理格局及其形成机制尚不清楚。本研究将以中国被子植物为研究对象，收集每个物种的生活型、成熟植株高度等生活史特征，结合整理全球气候数据，研究：1）被子植物性系统组成及其多样性的生物地理格局；2）中国被子植物性系统空间格局的形成机制；3）植物功能型对性系统空间格局及其形成机制的影响。性系统决定着支持生物多样性的资源水平，揭示被子植物性系统的生物地理格局及其对生物和非生物因子的响应，将加深对森林生态系统结构与动态及生物多样性格局与成因的理解，并对生物多样性保护及自然保护区的选择提供科学依据。

被子植物性系统的时空格局及其对环境变异的响应是生态系统结构和功能稳定性维持必需明确的关键科学问题。以往关于被子植物性系统的研究多基于单个或若干个物种或是零散的空间分布数据，被子植物性系统的生物地理格局及历史进化动态及其对气候变化的响应仍不清楚。本项目通过收集中国乃至全球被子植物性系统作为研究对象，收集每个物种的生活型、成熟植株高度等生活史特征，结合整理全球当代及新生代以来的气候数据，研究了1）被子植物性系统组成及其多样性的生物地理格局，及其生物因子（如生长型），非生物因子（如气候）及历史进化（群落进化年龄）对性系统组成的空间格局的相对影响。结果发现性系统与树高/生活型关系最为密切，二者在适应气候的变化过程中共同适应。同时，这几类生物和非生物因子及进化年龄对性系统组成的相对贡献因植物生长型而异，它们对木本植物性系统组成的解释率远高于草本植物。全球尺度上的性系统宏观进化的分析表明雌雄异株不是进化的盲端，且过去气候变化显著影响了不同性系统状态之间的转化。雌雄异株和雌雄同株异花植物的比例随温度升高而增加，而两性花植物的比例则在干旱的地区更常见。性系统决定着支持生物多样性的资源水平，揭示被子植物性系统的生物地理格局及其对生物和非生物因子的响应，将加深对森林生态系统结构与动态及生物多样性格局与成因的理解，并对生物多样性保护及自然保护区的选择提供科学依据。