Abstract:

Aims: Nature reserves are important barriers against invasive species. Human activities, however, can increase the risk of species invasions in these reserves and beyond. Comparative studies on the biodiversity and distribution patterns of invasive plant species within and outside nature reserves, as well as differences among nature reserves, may help elucidate the level of resistance among nature reserves and reveal the factors driving these differences.
Methods: We surveyed the invasive herbs from 380 plots of four national nature reserves (Chishui Alsophila, Xishui, Fanjingshan, and Mayanghe), in Guizhou Province. We contrasted the diversity of invasive herbs inside and outside the four nature reserves using a two-way analysis of variance, and explored differences in species composition with non-metric multidimensional scaling. Redundancy analysis was used to evaluate the key anthropogenic factors to explain these differences.
Results: A total of 46 invasive herbs were recorded and classified into 37 genera and 18 families. At each of the four reserves, between 7 and 20 invasive herb species were identified inside the reserve and between 10 and 24 invasive species were observed outside the reserve. The richness, Shannon-Wiener diversity index, and Simpson dominance index of invasive herbs outside Chishui and Fanjingshan nature reserves were significantly higher than those inside nature reserves, while there were no significant differences between invasive herbs inside and outside Xishui and Mayanghe nature reserves. Pielou’s evenness index inside Fanjingshan Nature Reserve was significantly higher than that outside the reserve, but no differences in evenness were found in the other nature reserves. In terms of invasive herb species composition, no significant differences inside and outside the four nature reserves were discovered. Redundancy analysis results showed that the residents and the length of roads were the key anthropogenic factors underlying the distribution pattern of invasive herbs.
Conclusions: Our results suggest that different reserves have different resistance to plant invasion, which results from differences in anthropogenic activity. We recommend that restriction of human activities in and around nature reserves can help to prevent the spread of invasive plant species.

Key words: nature reserve, invasive alien plant, plant diversity, human disturbance