地球暖化促进植物迁移与入侵

Global warming facilitates plant migration and biological invasion

在当今快速的全球气候变化 ,特别是快速而急剧的地球暖化情况下 ,现有植物及其系统被迫 :1)重新适应这种变化了及仍在变化着的环境条件 ;2 )往高海拔及极地方向迁移寻找合适的生存环境 ;或者 3)因其迁移的速度赶不上气候变化的速度而消亡。同时 ,气温升高和降水模式 (包括降水量及其分配 )的变化 ,以及与此相关联的干扰型式 (包括干扰种类、强度及延续时间 )的变化 ,一方面将使现有植物及其生态系统对外来生物的抗性弱化 ,另一方面将激活外来物种的活性 ,导致外来生物的快速扩散与大规模入侵 ,进而排挤和“杀死”当地乡土种 ,减少生物多样性 ,改变原有生态系统的组成、结构和功能 ,最终导致严重的社会经济与生态环境问题。在制定域、国家及全球经济与环境政策时 ,应充分考虑到这些问题 。

Global warming will lead to changes in many environmental factors and disturbance regimes (e g fire, drought, insect outbreak etc ) As a consequence, changes in characteristics of existing ecosystems, such as species composition and competition, stability and productivity, ecosystem health, ecological safety and ecosystem services, are to be expected Palaeoecological evidence and palaeoclimatic records pointed out plant pole ward migration in latitude and upward shift in elevation with increased temperature after the last glaciation Ecological observations also showed that the elevation of the alpine timberline moved upward worldwide with increasing global temperatures during the last 100 years Current global warming could mean that the plants currently growing at lower elevations or at lower latitudes might progressively migrate to higher elevations and latitudes However, it does not mean that all plants of an ecosystem move upward or pole ward with the same velocity Many species may re adapt to the changed and changing environmental conditions and survive for generations at their present location Many species will shift their ranges to track climate change As climate may change faster than plants are able to migrate from one region to another, species will become extinct An extinction of a plant species will also harm the animals depending on this specific species On the other hand, global warming and new disturbance regimes could favour the invasion of non native species due to the reduced stability and resistance of ecosystems Biological invasions will lead to massive losses of biological diversity on local, regional and global scales Global warming during the past 20 30 years has already had a severe impact on sensitive biological systems As a continued warming has to be expected, the global warming issue should be addressed by conservation planners and policy makers, as one of the most serious and immediate threats to biodiversity