Land cover changes assessment using object‐based image analysis in the Binah River watershed (Togo and Benin)

Abstract

In this study, land cover changes between 1972 and 2013 were investigated in the Binah River watershed (North of Togo and Benin) using remote sensing and geographic information system technologies. Multitemporal satellite images-Landsat MSS (1972), TM (1987), and OLI-TIRS (2013)-were processed using object-based image analysis and post-classification comparison methods including landscape metrics and changes trajectories analysis. Land cover maps referring to five main land cover classes, namely, agricultural land, forest land, savannah, settlements, and water bodies, were produced for each acquisition date. The overall accuracies were 76.64% (1972), 83.52% (1987), and 88.84% (2013) with respective Kappa statistics of 0.69, 0.78, and 0.86. The assessment of the spatiotemporal pattern of land cover changes indicates that savannah, the main vegetation type, has undergone the most dominant change, decreasing from 67% of the basin area in 1972 to 56% in 1987 and 33% in 2013. At the same time, agricultural land has significantly increased from 15% in 1972 to 24% in 1987 and 43% in 2013, while some proportions of agricultural land were converted to savannah relating to fallow agriculture. In total, more than 55% of the landscape experienced changes between 1972 and 2013. These changes are primarily due to human activities and population growth. In addition, agricultural activities significantly contributed to the increase in the number of patches, degree of division, and splitting index of forest and savannah vegetations and the decrease in their effective mesh sizes. These results indicate further fragmentation of forest and savannah vegetations between 1972 and 2013. Further research is needed to quantitatively evaluate the influences of individual factors of human activities and to separate these from the impacts of climate change-driven disturbances.

Spatio-Temporal Dynamics in Land Use and Habitat Fragmentation within a Protected Area Dedicated to Tourism in a Sudanian Savanna of West Africa

“…These dynamics attest to the ongoing deforestation in southern Burkina Faso. This conversion was also noticed elsewhere in West Africa (Badjana et al, 2015;Houessou et al, 2013;Zoungrana et al, 2015).…”

Land Use and Land Cover Dynamics Analysis of the Togodo Protected Area and Its Surroundings in Southeastern Togo, West Africa

“…In the context of a Guinean climate, we defined a dry year and a wet year based on the normalized precipitation index [45]. Since the purpose of our analysis was to understand the impacts of agriculture on natural vegetation, we combined trajectories considering forest and savannah as one natural vegetation class [13]. Likewise, all trajectories involving built areas and/or water were grouped under a single trajectory: "other".…”

“…The first of these is intensity analysis [12]. The second is the analysis of land cover change trajectories, aiding in better understanding the possible causes of LULC change and its effects [13].…”

“…In Togo, natural vegetation has undergone significant change as a result of human activities such as agricultural expansion, illegal tree logging, and incursions in protected areas [13,17]. Similarly, the Togodo Protected Area (TPA) and its surroundings are experiencing near-daily human threats, including poaching, clearing for agricultural purposes, logging, and charring for domestic needs and sale.…”

Analyzing Trends of Dike-Ponds between 1978 and 2016 Using Multi-Source Remote Sensing Images in Shunde District of South China

“…The estimation and monitoring of dike-pond changes are necessary to establish an integrated land and water resource management system [52,53]. As a typical agricultural mode in the Pearl River Delta, it is of great practical significance to implement ecological agriculture construction and sustainable development of regional social economy in developed regions.…”