Impact of rubber plantation on carabid beetle communities and species distribution in a changing tropical landscape (southern Yunnan, China)

Abstract

Carabid beetles (Coleoptera: Carabidae) have widely been used to assess biodiversity values of different habitats in cultivated landscapes, but rarely in the humid tropics. This study aimed to investigate effects of land use change on the carabid assemblages in a tributary valley of the Mekong River in tropical southern Yunnan, China. The study area includes habitats of traditional land use systems (rice production and shifting cultivation successions) and was dominated by natural forests until about 30 years ago. Since then, large areas of forest have been, and still are, successively transformed into commercial rubber monoculture plantations. In total, 102 species of Carabidae (including Cicindelinae) were recorded from 13 sites over different seasons, using pitfall traps, Malaise traps and aerial collectors in trees. Cluster analysis and indicator species analysis showed that three types of habitat (rice field fallows, early natural successions and natural forest) possess a degree of uniqueness in species composition. Non-metric multidimensional scaling revealed that the environmental factors explaining 80% of the total variation in carabid assemblage composition are the degree of vegetational openness of a habitat and its plant species diversity. Rice field fallows had significantly higher numbers of species and individuals than any other type of habitat and are probably dominated by species originating from other regions. Carabid assemblages of young rubber plantations (5 and 8 years) were quantitatively similar to those of forests, but without species of significant indicator value. With increasing plantation age (20 and 40 years), the number of carabid species decreased. Increasing age and a further spatial expansion of rubber plantations at the expense of forest areas will have negative impacts on the native forest carabid assemblages with strongest effects on forest specialists and rare species.

Tree Diversity Mediates the Distribution of Longhorn Beetles (Coleoptera: Cerambycidae) in a Changing Tropical Landscape (Southern Yunnan, SW China)

“…This, however, was not the case in certain other groups of insects recorded from the same region. For example, Meng et al [43] found that the species richness and densities of ground beetles (Carabidae) were significantly higher in open habitats and rice field fallows than in other habitat types of this landscape, including forest, and are probably dominated by species originating from other regions with natural open vegetation. Furthermore, rice field fallows, early natural successions and natural forest each possess a degree of uniqueness in ground beetle species composition.…”

Increasing Demand for Natural Rubber Necessitates a Robust Sustainability Initiative to Mitigate Impacts on Tropical Biodiversity

“…), [7] Yunnan, China (Meng et al . ), and [8] Sumatra, Indonesia (Thiollay ). Numbers at top of bars represent species richness of natural forest for each study.…”

“…This pattern is similar for carabid beetles in China (Meng et al . ), and bats in Indonesia (Danielsen & Heegaard ) and Thailand (Phommexay et al . ), where 13 species were restricted to forest, and insectivorous bats showed 20‐fold lower activity in rubber (355 individuals from 24 species in forest, versus 16 individuals from eight species in plantations) attributed to lower insect biomass.…”

Urban Expansion and Its Impact on the Land Use Pattern in Xishuangbanna since the Reform and Opening up of China

“…Considering the convenience of management and transportation [55], rubber was mainly planted around urban areas, rural settlements, roads and rivers. Thus, the expansion of urban areas and the development of the road network enhanced the connectivity and aggregation of rubber (Table 5), while also leading to negative impacts on biodiversity, especially insects, such as beetles, spiders and wild bees [56,57]. In 1991, the Regulations on Lancang River Basin Protection in Xishuangbanna was passed for the purpose of the protection and rational exploitation of Lancang River Basin.…”