外来物种入侵与本土物种分布区扩张的异同

Comparisons between non-native species invasion and native species range expansion

当今全球变化背景下,物种分布区正发生着快速变化,一类是人类活动介导下的生物入侵过程,另一类是本土物种的自然分布区扩张。两者之间既具有相似之处,亦有明显差异。探讨两者间异同是发展外来入侵物种管控和本土物种保护策略的基础科学问题。本文以两栖爬行类、鸟类和哺乳类等陆栖脊椎动物为例,在阐述外来物种入侵过程的基础上,将其与本土物种的分布区变化进行比较并阐述了两者间的异同。我们发现,伴随经济贸易发展和人口流动,外来物种正在加剧入侵;同时,发生分布范围变化的本土物种数量也在迅速增加。两者在分布区变化过程中的驱动因子、时空尺度、发生速度、物种特征的预测能力以及对新分布区的影响方面具有明显差异:人类活动介导下的外来物种入侵通常会经历长距离迁移,甚至跨越生物地理区系,并在入侵区快速扩散,物种特征在预测外来物种入侵过程中起着重要作用,对当地生物多样性造成严重威胁;本土物种分布区扩张通常发生在原生范围的邻近区域,发生速度较慢,物种特征在预测分布区扩展中的作用有限,且对新区域的负面影响较小。由于在短期内很难全面判定外来物种和发生分布区变化的本土物种的生态影响,我们建议应对新分布区内的外来物种和本土物种进行密切监测和长期研究,对其可能引发的生态学效应进行早期预警和评估,以最大限度地限制其潜在危害并保护生物多样性。

Background&Aim:In response to the rapid global change,a growing number of species have been undergoing range shifts,which includes two main processes:one is the non-native species invasion mediated by human activities,and the other is the natural range expansion of native species.There are both similarities and differences between these two processes.It is thus critically important to distinguish their similarities and differences to develop scientific strategies for invasive species prevention and native species conservation.Progresses:By comparing the non-native species invasion and native species range expansion,we found that both non-native species invasion and native species range expansion are increasing under global change.However,there are obvious differences in potential drivers,spatial-temporal scales,occurring rates,species traits predicting the process,and impacts on new ranges between the two processes.The non-native species invasion usually occurs over long distance with the aid of human activity,spreads rapidly after establishment,high predictive ability of species traits,and poses a serious threat to local biodiversity.By contrast,range expansion of native species usually occurs at smaller spatial scales,slower occurring rates,and lower predictive ability of species traits,thus generally has less impacts on new regions.Prospects:As it is difficult to accurately determine the potential impacts of new-arrival species on recipient habitats,long-term monitoring and studies assessing the biological and ecological effects of these two processes on local population dynamics,community structure,and ecosystem function are needed,which is important to develop schemes of non-native species mitigation and native biodiversity conservation.