Land use and land cover (LULC) under improper land management is a major challenge in sub-Saharan Africa and has drastically affected ecological security. Addressing environmental impacts related to this challenge requires efficient planning strategies based on the measured information of land use patterns. This study assessed the ecological risk index (ERI) of Zanzibar based on LULC. A random forest classifier was used to classify three Landsat images of Zanzibar for the years 2003, 2009, and 2018. Then, a land change model was employed to simulate the LULC changes for 2027 under a business-as-usual (BAU), conservation, and extreme scenarios. Results showed that the built-up areas and farmland of Zanzibar Island have increased constantly, while the natural grassland and forest cover have decreased. The forest, agricultural, and grassland were highly fragmented into several small patches. The ERI of Zanzibar Island increased at a constant rate and, if the current trend continues, this index will increase by up to 8.9% in 2027 under an extreme scenario. If a conservation scenario is adopted, the ERI will increase by 4.6% whereas if a BAU policy is followed, this value will increase by 6.2%. This study provides authorities with useful information to understand better the ecological processes and LULC dynamics and prevent unmanaged growth and haphazard development of informal housing and infrastructure.

中文翻译：

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基于土地覆被变化的生态风险评估：以桑给巴尔（坦桑尼亚）为例

在撒哈拉以南非洲，土地管理不当造成的土地利用和土地覆盖是一个重大挑战，已经严重影响了生态安全。解决与这一挑战相关的环境影响，需要基于测得的土地利用模式信息的有效规划策略。这项研究基于LULC评估了桑给巴尔的生态风险指数（ERI）。使用随机森林分类器对2003年，2009年和2018年的三幅桑给巴尔Landsat影像进行分类。然后，采用土地变化模型来模拟2027年照常营业（BAU），保护下的土地利用变化，以及极端情况。结果表明，桑给巴尔岛的建成区和耕地面积在不断增加，而天然草地和森林覆盖率却在下降。森林，农业 和草原被高度分割成几个小块。桑给巴尔岛的ERI以恒定速度增长，如果当前的趋势持续下去，那么在极端情况下，该指数到2027年将增长8.9％。如果采用保护方案，则ERI将增加4.6％，而如果遵循BAU政策，则该值将增加6.2％。这项研究为当局提供了有用的信息，以更好地了解生态过程和土地利用，土地利用变化和林业的动态，并防止非正式住房和基础设施的不受控制的增长和偶然发展。ERI将增加4.6％，而如果遵循BAU政策，则该值将增加6.2％。这项研究为当局提供了有用的信息，以更好地了解生态过程和土地利用，土地利用变化和林业的动态，并防止非正式住房和基础设施的不受控制的增长和偶然发展。ERI将增加4.6％，而如果遵循BAU政策，则该值将增加6.2％。这项研究为当局提供了有用的信息，以更好地了解生态过程和土地利用，土地利用变化和林业的动态，并防止非正式住房和基础设施的不受控制的增长和偶然发展。