A spatio-temporal analysis of the magnitude and trend of land use/land cover changes in Gilgel Gibe Catchment, Southwest Ethiopia

Influence of environmental variables and anthropogenic activities on soda-saline lakes chemistry in northern Tanzania: A remote sensing and GIS approach

This study employed Remote Sensing and Geographical Information Systems to explore the influence of environmental factors and human-induced land use/land cover changes on the chemistry of soda-saline lakes in Northern Tanzania. Satellite-based rainfall data were sourced from the Climate Hazards Group Infrared Precipitation with Station (CHIRPS) datasets, and temperature data were obtained from MERRA-2. Monthly precipitation, temperature, and drought conditions in lake watersheds were analyzed from 1981 to 2022, while land use and land cover changes were assessed for 2000, 2014, and 2023. Soil types were acquired from the FAO Digital Soil Map of the World, while geological characteristics were sourced from the US Geological Survey database. The findings revealed that the region's climate is ideal for enhancing evapotranspiration, leading to mineral precipitation, and altering the chemistry of soda-saline lakes. The Standardized Precipitation Evapotranspiration Index revealed increased drought events in the lake basins since 1987, with prolonged drought occurrence between 2000 and 2017. The results also showed that the region is characterized by a variety of soil types, including ferric acrisols, chromic cambisols, calcic cambisols, entisols, inceptisols, eutric fluvisols, distric nitisols, humic nitisols, mollic andosols, ochric andosols, and pellic vertisols. Furthermore, the region is distinguished by diverse geological processes, from Precambrian-Cambrian to tertiary intrusive, triggered by volcanic and tectonic activity. Land use/land cover changes results indicated dynamics in the various classes with an overall decrease in areas under water bodies (-39.80 %), forests (-22.57 %) and bareland (-36.18) while agricultural land (111.01 %) built-up areas (434.72 %), shrubs and grasses (72.77 %) increased in area coverage over the 23 years study period (2000-2023). This study underscores the complex interplay between environmental variables and human activities in shaping the chemistry of soda-saline lakes.

Effects of land management technology adoptions on land use land cover dynamics using GIS and remote sensing: the case of Goyrie watershed, southern Ethiopia

Understanding land use/land cover (LULC) changes is crucial for informing policymakers and planners on the dynamics affecting environmental and resource management. Most past studies highlighted the significance of LULC changes and their driving forces in various locations. However, comprehensive analyses that combine the impact of land management technologies (LMTs) on LULC changes using GIS and remote sensing tools have not been widely addressed. Thus, the study analyzes the effects of LMT adoptions on LULC dynamics and the Normalized Difference Vegetation Index (NDVI) in the Goyrie watershed from 1993 to 2022. It also examines household perceptions of the cause of LULC changes. Methodologically, Landsat 5 TM (1993), Landsat 5 ETM + (2008), and Landsat 8 OLI/TIRS (2022) images were employed to analyze LULC changes and NDVI. Binary logistic regression models were used to identify households' perceptions of the causes of LULC changes. The findings revealed that the Goyrie watershed has experienced significant LULC changes since 1993. During the entire study period, the shares of grassland, shrub land, cultivated land, and settlement areas increased by 89.4%, 8.5%, 53.6%, and 1613.4% from their original sizes, respectively. Conversely, the coverage of bare land and forest land declined by 99.5% and 99.7%, with annual rates of decline of 3.29% and 3.3%, respectively. Throughout the study period, the increasing trends in grassland and shrub land, along with the decline in bare land, were attributed to LMT practices. The NDVI values of moderate and dense vegetation density decreased by 81.8% and 92.2%, respectively, from 1993 to 2022 due to the expansion of settlement areas and cultivated lands. Population pressure, expansion of settlements and agriculture, fuel extraction, LMTs, and policy issues significantly influenced the LULC changes. The study concludes that more sustainable and integrated LMT practices should be essential to managing the related risks of LULC changes.

Effects of participatory forest management programs on Land use/land cover change and its Determinants in Alle District, southwest Ethiopia

In order to create sustainable conservation policies for biodiversity, it is imperative that participatory forest management (PFM) be assessed. Forests contribute to the sustainability of the planet by controlling soil erosion in agricultural areas and by moderating the effects of climate change. However, Ethiopia's forest resources have been under intense pressure because of the increased demand for wood products and agricultural conversion. As one of the potential solutions, the PFM programme was implemented in 1990. This study set out to investigate the effects of the PFM programme on land use and land cover (LULC) in the Alle district of southwest Ethiopia, as well as the variables influencing community involvement and the obstacles to PFM implementation and community involvement. Changes in forest cover were detected using Landsat images from 1992, 2012, and 2022 obtained from Thematic Mapper (TM), Enhanced Thematic Mapper (ETM+), and Operational Land Imager (OLI). Images were obtained during the dry season and were cloud-free. A total of 240 respondents were chosen by means of a straightforward random sampling technique, and survey data were collected using questionnaires, interviews, and field observations. Data were analyzed using ArcGIS 10.5, ERDAS Imagine 2015, SPSS version 20, and Excel 2010. The change in forest cover shows an increasing trend from 2012 to 2022. Again, grassland and wetland coverage in this study decreased rapidly. In the years 2012-2022, forest land increased from 462.7ha (74.8 %), to 569.8ha (92.1 %), while, the agricultural land, grassland, and wetland were reduced from 109.5ha (17.7 %) to 37.8ha (6.1 %), 31.9ha (5.2 %) to 0.0ha (0.0 %); 14.1 ha (2.3 %), to 10.8 ha (1.7 %) respectively. There have been beneficial developments in the forests over the last 30 years. The binary logistic regression model disclose that, land ownership had a negative impact on forest management participation, while other factors such as gender, education level, family size, TLU, access to credit, training, and law enforcement had a positive and significant (p < 0.05) effect on PFM practices. LULC change in study area causes rapid wetland ecosystem deterioration, which may result in the extinction of the most significant and ecologically valuable species and a loss of biodiversity in the environment. In this context, developing an integrated participatory approach requires rapid attention, and all farmers and stakeholders must be actively involved in PFM programs.

Characterizing landscape fragmentation of Koitobos river sub-basin, Trans-Nzoia, Kenya

The changes in landscape structure and functioning due to unprecedented human interference are hastening across the globe and it is thus a compelling necessity to preserve and restore our ecosystems. This study aimed to characterize levels of landscape fragmentation, habitat structure, driving forces, and perceptions of the residents on the most preferred reconfiguration approaches. The land use/land cover [LULC] change was first determined by interpreting the 1973, 1986, 1995, 2002, 2014, and 2022 Landsat images using the QGIS 3.26 while the selected landscape fragmentation metrics were analyzed using FRAGSTATS 4.2. Forests, shrubs, and grasslands showed a declining trend, except for agriculture, water, and built-up areas, which depicted high increases for the study periods [1973 to 2022]. The landscape of the study area is characterized as progressively fragmenting as signified by high escalated values of patch number [374 %], edge density [7828 %] between 1986 and 2002, contagion [10.3%], and a declined value of Shannon Diversity Index [SHDI] [-17.42%], Shannon evenness index [SHEI] [-25.8 %] and connectedness [-43.3%]. Considering these results, high losses of forests and grasslands coupled with expansive farmlands and built-up areas have led to unprecedented landscape fragmentation From field surveys and oral interviews, this has not only left streams vulnerable to massive sediment loads but has also triggered annual floods which occur during wet months even though change in onset of rainfall seasons was also reported. The findings call for restoration and integrated and sustainable restoration efforts, especially for the forests, grasslands, and riparian corridors along with sustainable urban planning and community-based sensitization on watershed management.