Deforestation and fragmentation of natural forests in the upper Changhua watershed, Hainan, China: implications for biodiversity conservation

Abstract

Hainan, the largest tropical island in China, belongs to the Indo-Burma biodiversity hotspot. The Changhua watershed is a center of endemism for plants and birds and the cradle of Hainan's main rivers. However, this area has experienced recent and ongoing deforestation and habitat fragmentation. To quantify habitat loss and fragmentation of natural forests, as well as the land-cover changes in the Changhua watershed, we analyzed Landsat images obtained in 1988, 1995, and 2005. Land-cover dynamics analysis showed that natural forests increased in area (97,909 to 104,023 ha) from 1988 to 1995 but decreased rapidly to 76,306 ha over the next decade. Rubber plantations increased steadily throughout the study period while pulp plantations rapidly expanded after 1995. Similar patterns of land cover change were observed in protected areas, indicating a lack of enforcement. Natural forests conversion to rubber and pulp plantations has a general negative effect on biodiversity, primarily through habitat fragmentation. The fragmentation analysis showed that natural forests area was reduced and patch number increased, while patch size and connectivity decreased. These land-cover changes threatened local biodiversity, especially island endemic species. Both natural forests losses and fragmentation should be stopped by strict enforcement to prevent further damage. Preserving the remaining natural forests and enforcing the status of protected areas should be a management priority to maximize the watershed's biodiversity conservation value.

Landscape composition and configuration in the central highlands of Ethiopia

“…In general, habitat loss and habitat fragmentation are the observed scenarios for forestland use, which corroborates the findings of Putz et al. () and Zhai, Cannon, Dai, Zhang, and Xu ().…”

Forest fragmentation in China and its effect on biodiversity

“…Patches continue to shrink in size in some regions. For example, there have been nine‐, two‐, and threefold decreases in mean patch size in Nenjiang River Basin between 1954 and 2010, Changbai Mountain between 1972 and 1988, and the upper Changhua Watershed between 1988 and 2005, respectively (Zheng et al , ; Tang et al , ; Zhai et al , ). Several studies have examined the effects of fragment size on the survival of animal species (Table ).…”

“…The matrix of vegetation between forest patches is another key factor because it affects the likelihood of organisms moving between patches (Ewers & Didham, ). China's forest fragments are mostly distributed in agricultural landscapes (Liu & Tian, ), and non‐native tree plantations (Xu, ; Zhai et al , ). Others are surrounded by water as a result of dam construction (Wu et al , ; Yu et al , ) or found within urban areas (Yu & Ng, ).…”

“…Therefore, forest fragmentation was still common in many regions (Feng et al, 2011). Natural forests became fragmented into smaller, isolated patches despite an increase in forest cover (of plantations) -in biomes ranging from tropical rainforest to boreal forest -over the past half century (Li et al, 2009a;Feng et al, 2011;Gong et al, 2013;Zhai et al, 2015;Hua et al, 2018).…”

“…For example, bird diversity in artificial forests is much lower than in native forest fragments (Hua et al, 2016). Some nature reserves are also becoming increasingly fragmented (Wang et al, 2013a;Zhai et al, 2015).…”