Have China's national forest reserves designated since 1990 conserved forests effectively?
Have China's national forest reserves designated since 1990 conserved forests effectively?
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DOI：
10.1016/j.jenvman.2022.114485
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发表时间：
2022-01
影响因子：
8.7
通讯作者：
Yu Xu;Megan Price;Biao Yang;Kai Zhang;N. Yang;Xiaoxin Tang;J. Ran;Y. Yi;Bin Wang
中科院分区：
文献类型：
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作者：
Yu Xu;Megan Price;Biao Yang;Kai Zhang;N. Yang;Xiaoxin Tang;J. Ran;Y. Yi;Bin Wang
世纪后半叶，人类活动造成中国森林严重退化。因此，中国制定了雄心勃勃的天然林保护和植树造林计划，以保护和扩大森林。然而，目前还不清楚这些计划，特别是森林保护区的指定，如何影响森林覆盖率和破碎化。本文通过分析1990年以来中国国家森林保护区的四个森林指标（即，森林覆盖率，平均森林斑块大小，平均森林斑块旋转半径和森林斑块凝聚力指数）来自1990年至2019年新产生的30米年度中国土地覆盖数据集。我们发现，从指定保护区的基准年到2019年，保护区及其周边地区的整体森林覆盖率增加，破碎度下降，只有保护区的森林覆盖率相对于基准的增加明显大于周边地区。国家保护区的指定时间对四个指标的变化没有很大的影响，但对于地带性，核心区森林斑块凝聚力指数相对于基线比缓冲区和过渡区显着增加。然而，在森林覆盖率很高的保留地，森林覆盖率下降，破碎化增加，这表明人类活动具有破坏性，管理无效。因此，森林保护和更新计划取得了一定的成功。我们建议需要作出重大改进，以确保更好地保护现有森林，减少威胁，促进有效管理。
China's forests were severely degraded by human activities during the latter half of the 20th century. Therefore, China enacted ambitious programs of natural forest protection and afforestation to protect and expand forests. Yet it is unclear how the programs, especially the designation of forest reserves, have affected forest cover and fragmentation. We evaluated the effectiveness of China's national forest reserves designated since 1990 in conserving forests, by analyzing four forest metrics (i.e., percentage forest cover, mean forest patch size, mean forest patch radius of gyration, and forest patch cohesion index) derived from a newly produced 30 m annual China land cover dataset from 1990 to 2019. We found that overall forest cover increased and fragmentation decreased from baseline years, when reserves were designated, to 2019 in both reserves and their surrounding areas, and only the increase in forest cover relative to baseline was significantly greater in reserves than in surrounding areas. The designation time of reserves under national protection had no considerable effect on changes in the four metrics, but for zonation, the core zone showed a significantly higher increase in forest patch cohesion index relative to baseline than the buffer and transition zones. Nevertheless, forest cover declined and fragmentation increased in highly forested reserves, suggesting destructive human activities and ineffective management. Thus, forest protection and regeneration programs were moderately successful. We recommend that there is significant improvement needed to ensure greater protection of existing forests and reduction of threats to promote effective management.