首页分享中国裸子植物的物种多样性格局及其影响因子

中国裸子植物的物种多样性格局及其影响因子

来源：花匠小妙招时间：2025-01-08 06:17

摘要：

物种多样性的大尺度空间格局是宏观生态学和生物地理学研究的核心问题之一。本文利用中国裸子植物分布数据, 结合气候、地形等环境信息, 分析了中国裸子植物物种多样性的大尺度格局及其影响因素, 比较了不同类群之间物种多样性格局和主导因子的差异, 并探讨了裸子植物在植物区系中所占比重的地理格局。结果表明, 中国裸子植物的物种多样性总体上呈现南高北低的趋势, 物种多样性在横断山区最高。在裸子植物的三个主要类群中, 松柏亚纲的物种多样性格局与整体相似, 买麻藤亚纲的多样性高值区则出现在中国西北部的干旱地区, 苏铁亚纲的分布区较为狭窄, 主要集中在南方地区。线性回归分析结果表明, 空间异质性和降水因子对中国裸子植物多样性格局的解释率最高, 末次冰期以来的气温变化、海拔高差和能量因子次之。这表明中国裸子植物物种多样性的格局受到了多种因素的影响, 其中空间异质性和降水因子影响最大。进一步分析发现, 物种多样性格局的主导因子在不同类群之间具有显著差异, 这可能反映了这些类群的进化历史以及生理适应的差异。裸子植物与被子植物的比例具有明显的空间格局: 在东部、南部气候环境优越的地区, 裸子植物与被子植物的比例低于0.06; 而在西部、北部等气候环境比较恶劣的地区, 裸子植物的比例则显著上升。回归分析表明, 能量和水分因子显著影响了裸子植物与被子植物的比例。随着能量的降低和降水的减少, 裸子植物与被子植物的比例会显著升高, 这可能是由于被子植物在温暖湿润地区具有较强竞争优势, 但裸子植物对极端环境具有更好的适应。

关键词: 松柏亚纲, 买麻藤亚纲, 苏铁亚纲, 现代气候假说, 过去气候变化, 物种多样性

Abstract

How large-scale patterns of species diversity emerge is a central yet controversial issue in ecology and biogeography. Despite the long history of studies the mechanisms driving species diversity patterns in space remain poorly known. Using distribution data of all gymnosperm species in China, we assessed the influence of environmental factors on spatial patterns of species diversity in China. Further, we evaluated the proportion of gymnosperms in local floras. We found that species diversity of gymnosperms decreases along a south-north axis. Hengduan Mountains, with the highest species diversity, is a hotspot of gymnosperms. Species diversity patterns differ significantly between the gymnosperm subclasses. In particular, the species diversity pattern of Pinidae is similar to that of all species combined, while the species diversity of Gnetidae is highest in the drylands of northwestern China. In contrast, Cycadidae is restricted to southern China. Environmental heterogeneity and precipitation are the best predictors of species diversity patterns of all gymnosperms combined, followed by temperature anomaly since the Last Glacial Maximum (LGM), elevational range and energy. That different factors predict species diversity patterns of different gymnosperm subclasses, may reflect the differences in their evolutionary history and physiological adaptions. The ratio of gymnosperm to angiosperm species diversity is lower in the warm and humid eastern and southern parts of China, and increases towards the drylands in western and northern parts. Environmental energy and precipitation were good predictors of the ratio of gymnosperms to angiosperms. Specifically, the ratio decreases with increase of energy and decrease of precipitation suggesting that angiosperms may have stronger competitive ability in warm and humid regions while gymnosperms adapt better to dry and cold environments.

Key words: Pinidae, Gnetidae, Cycadidae, contemporary climate hypothesis, past climate change, species diversity pattern