Forest fragmentation in China and its effect on biodiversity

Abstract

Land‐use change is fragmenting natural ecosystems, with major consequences for biodiversity. This paper reviews fragmentation trends – historical and current – in China, the fourth largest country on Earth, and explores its consequences. Remote sensing makes it possible to track land‐use change at a global scale and monitor fragmentation of dwindling natural landscapes. Yet few studies have linked fragmentation mapped remotely with impacts on biodiversity within human‐modified landscapes. Recent reforestation programs have caused substantial increases in forest cover but have not stopped fragmentation, because the new forests are mostly monocultures that further fragment China's remnant old‐growth lowland forests that harbour the highest levels of biodiversity. Fragmentation – and associated biodiversity declines – is unevenly distributed in China's forests, being most problematic where agricultural expansion is occurring in the southwest and northeast, serious in the densely populated eastern regions where urbanisation and transport infrastructure are modifying landscapes, but less of a problem in other regions. Analyses of temporal trends show that the drivers of forest fragmentation are shifting from mainly agricultural expansion to urbanisation and infrastructure development. Most of China's old‐growth forests persist in small, isolated fragments from which many native species have disappeared, on land unsuitable for human utilisation. Fragmentation throughout China is likely to have major consequences on biodiversity conservation, but few studies have considered these large‐scale processes at the national level. Our review fills this research gap and puts forward a systematic perspective relevant to China and beyond.

Understanding Current and Future Fragmentation Dynamics of Urban Forest Cover in the Nanjing Laoshan Region of Jiangsu, China

“…Specifically, we estimated a potential decrease of total forest area from 209.4 km 2 to 123.9 km 2 between 2002 and 2023 (40.8% decrease, about 52.3-88.4% of the total area). While we predicted about an 82.8% increase of the total urban area from 17.23 to 99.92 km 2 Figure S4 shows the highest annual land use dynamic degree of the urban area among all four types, with 29.2% from 2002 to 2018 and 22.9% from 2002 to 2023. This also indicates a rapidly expanding trend of urbanization.…”

“…Meanwhile, forest area gains were adding 0.35 km 2 of forest interior and intact area, which was a fourth lower than that of other fragmented forests. Net forest loss in relation to forest interior and intact area (by 57.73 km 2 ) was approximately twice greater than other fragmented forests (by 29.58 km 2 ). We found a large area forest loss from intact and interior forest in the western forests of this study area, which was especially true for loss from intact forest.…”

“…Natural and anthropogenic disturbances during the process of urbanization strongly affect biodiversity and ecosystem dynamics in urban ecosystems, through the alteration of species richness, carbon stocks, and microclimates [1,2]. Forested urban ecosystems are vulnerable to forest cover loss and fragmentation [3][4][5].…”

On the Management of Large-Diameter Trees in China’s Forests

“…While China has strict regulations on biodiversity conservation, many of these forests have been protected under national protection programs. Yet some of them are fragmented and are disappearing [53,54]. Given that large-diameter trees in natural forests are vulnerable to habitat loss and fragmentation [29], atmospheric drought and other anthropogenic disturbances [35], the fate of large-diameter trees in these forests still hangs in the balance.…”

Spatio–Temporal Changes of Forests in Northeast China: Insights from Landsat Images and Geospatial Analysis

“…The similar fragmentation process of forests in the mountainous area of east Jilin Province was also observed during 1954-2000 [48]. Liu et al [62] classified the northeast region of China as the most problematic area of forest fragmentation based on 138 previous studies' data. Thus, the fragmentation induced by natural and human-induced disturbances in this region should draw much more attention from government and scientists.…”