Rana Suresh K, Dangwal Bhawana, Rawat Gopal S, Price Trevor D
G.B Pant National Institute of Himalayan Environment Almora Uttarakhand India.
Wildlife Institute of India Dehradun Uttarakhand India.
Ecol Evol. 2024 Feb 9;14(2):e10884. doi: 10.1002/ece3.10884. eCollection 2024 Feb.
Differences in the number of alien plant species in different locations may reflect climatic and other controls that similarly affect native species and/or propagule pressure accompanied with delayed spread from the point of introduction. We set out to examine these alternatives for Himalayan plants, in a phylogenetic framework. We build a database of alien plant distributions for the Himalaya. Focusing on the well-documented regions of Jammu & Kashmir (west) and Bhutan (east) we compare alien and native species for (1) richness patterns, (2) degree of phylogenetic clustering, (3) the extent to which species-poor regions are subsets of species-rich regions and (4) continental and climatic affinities/source. We document 1470 alien species (at least 600 naturalised), which comprise ~14% of the vascular plants known from the Himalaya. Alien plant species with tropical affinities decline in richness with elevation and species at high elevations form a subset of those at lower elevations, supporting location of introduction as an important driver of alien plant richness patterns. Separately, elevations which are especially rich in native plant species are also rich in alien plant species, suggesting an important role for climate (high productivity) in determining both native and alien richness. We find no support for the proposition that variance in human disturbance or numbers of native species correlate with alien distributions. Results imply an ongoing expansion of alien species from low elevation sources, some of which are highly invasive.
不同地点外来植物物种数量的差异可能反映了气候和其他类似影响本地物种的控制因素，以及/或者伴随着从引入点的延迟扩散而来的繁殖体压力。我们着手在系统发育框架下研究喜马拉雅植物的这些可能性。我们建立了喜马拉雅外来植物分布的数据库。聚焦于查谟和克什米尔（西部）以及不丹（东部）记录完备的地区，我们比较外来物种和本地物种在以下方面的情况：（1）丰富度模式；（2）系统发育聚类程度；（3）物种贫乏地区是物种丰富地区子集的程度；（4）大陆和气候亲缘关系/来源。我们记录了1470种外来物种（至少600种已归化），占喜马拉雅已知维管植物的约14%。具有热带亲缘关系的外来植物物种丰富度随海拔升高而下降，高海拔地区的物种是低海拔地区物种的一个子集，这支持了引入地点是外来植物丰富度模式的重要驱动因素这一观点。另外，本地植物物种特别丰富的海拔地区外来植物物种也丰富，这表明气候（高生产力）在决定本地和外来物种丰富度方面发挥着重要作用。我们没有找到证据支持人类干扰的差异或本地物种数量与外来物种分布相关的观点。结果表明外来物种正在从低海拔来源不断扩张，其中一些具有高度入侵性。
