Ecological Risk Assessment Based on Land Cover Changes: A Case of Zanzibar (Tanzania)

Abstract

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.

A Framework to Calculate Annual Landscape Ecological Risk Index Based on Land Use/Land Cover Changes: A Case Study on Shengjin Lake Wetland

“…Free cloud computing platforms, such as Google Earth Engine (GEE), currently promote the use of time-series satellite data for online batch processing [33]. Second, as per previous studies [2], [15], [29], [34], the selection of weights for parameters is important, and expertise is needed in this regard. Each individual LERI was constructed using the common landscape disturbance index and landscape vulnerability index, where a priori weights for different land cover types or components were needed.…”

“…The landscape vulnerability index is a comprehensive measure of the sensitivity and resistance of different landscape types to external interferences; when the resistance ability is lower, the risk to the ecosystem is greater. Based on existing studies [23], [28], [29] and knowledge on the study region, the resistance ability of landscapes was assigned a weight from 1 to 6 (i.e., impervious surfaces, cultivated land, forest, water bodies, reed beaches, and mudflats, respectively). To obtain an effective result, these values were normalized prior to use in subsequent calculations.…”

Ecotourism risk assessment in Yaoluoping Nature Reserve, Anhui, China based on GIS

“…It mainly went through embryonic stage, human health assessment stage, ecological risk assessment stage, and the multiscale comprehensive ecological risk assessment stage from the 1990s to the present (Kapustka 2005;Thomsen et al 2012;Hua et al 2017;Xu et al 2018). In recent years, scholars have extended and improved the study of ecological risk assessment to landscape, region, watershed, and other levels (Detenbeck et al 2000;Leuven and Poudevigne 2002;Bayliss et al 2012;Xu et al 2013;Li et al 2018;Omar and Cabral 2020).…”

The Monitoring of Non-Farming and Non-Grain Purposes in Arable Land of Zhejiang, China With Domestic Satellite Imagery

“…For the monitoring of non-farming, satellite remote sensing technology has become an indispensable way to capture the human activities from the perspective of land cover change (Omar et al, 2020;Nguyen et al, 2020). Lots of studies concentrate on the change in macro level with low and medium-resolution images (Keil et al, 2015;Saurabh et al, 2020;Chen et al, 2021), or in straightforward, they observed a large area of arable land transformed into forest, buildings, etc.…”