Land Use Change Trends and Their Driving Forces in the Kilombero Valley Floodplain, Southeastern Tanzania

Abstract

Land use change (LUC) driven by human activities and natural factors has resulted in the global loss of native biodiversity and the alteration of ecological processes and services across different ecosystems. It is thus necessary to analyze the trends and driving factors that influence land use changes. In this study, moderate resolution Landsat images were freely downloaded from the United States Geological Survey (USGS) archives, analyzed using the random forest (RF) algorithm and mapped in ArcGIS 10.2 software to examine the LUC trends from 1990 to 2016 in the Kilombero valley floodplain (KVFP), Tanzania. Participatory rural appraisals (PRA) and household questionnaire surveys were used to assess the potential drivers of LUC. The results show that, from 1990 to 2016, the agricultural land and grassland increased by 11.3% and 13.3%, respectively, while the floodplain wetland area decreased from 4.6% in 1990 to 0.9% in 2016. Based on a questionnaire survey, the intensification of human activities was identified as the proximate driver while population growth, a growing market demand and price incentives for agricultural and forest products coupled with improved infrastructure and biophysical factors such as soil properties, climate variability and terrain characteristics were identified as the underlying drivers of LUC. However, there is interplay among these factors acting simultaneously as well as differently that influence land use changes. Based on these findings, future sustainable land management strategies should include the introduction of the alternative environmentally friendly sources of livelihood, such as beekeeping, the promotion of community participation and education on the importance of sustainable wetland management.

The Impact of Land Use/Land Cover Change (LULCC) on Water Resources in a Tropical Catchment in Tanzania under Different Climate Change Scenarios

“…Soils in the floodplain are largely heavy black cotton soils, with a good water content at field capacity, but also some patches of sandy soils [23]. According to the Harmonized World Soil Database (HWSD) most parts of the catchment are covered by acrisols, with some areas dominated by cambisols in the western part and nitisols in the Udzungwa mountains [44].…”

“…The most important crops grown in the valley are sugarcane (Saccharum officinarum), maize (Zea mays), paddy rice (Oryza sativa), and cassava (Manihot esculata) [23]. Rice production is dominated by small-scale farmers and rain-fed agriculture, although some small irrigations schemes do exist in the valley.…”

“…This study exemplarily analyzes LULCC compared to climate change in the Kilombero Catchment in Tanzania and how these affect water resources. The catchment itself is subject to aforementioned LULCC [1,13] and pressure on land resources in the valley is fostered by government plans to implement the Southern Agricultural Growth Corridor of Tanzania (SAGCOT) [22], which is accompanied by a growing population and migration of pastoralists into the valley [23]. SAGCOT follows a green growth approach covering three development clusters in Kilombero, Ihemi, and Mbarali, comprising one third of the mainland of Tanzania [1,24,25].…”

“…However, deforestation is becoming more important with the increasing population and the growing demand for timber, fuelwood and charcoal production [28]. Other drivers of change are economic development, foreign agricultural investments, agro-technological advancements, favorable biophysical factors, policies, the aforementioned population growth, and increased migration of pastoralists into the valley [23,28]. These LULCC will affect ecosystem services and water resources in the catchment and scientific guidance is needed in order to enable a sustainable development of the catchment [1,13].…”

Use of Intensity Analysis to Characterize Land Use/Cover Change in the Biggest Island of Persian Gulf, Qeshm Island, Iran

“…Therefore, to analyze and understand LUCC, it is necessary to use proper technologies and innovative measurement methods [9,10] such as remote sensing (RS) and geographical information systems (GIS). Utilization of these powerful technologies not only accelerates the process, but also provides a thorough understanding of status and trend of each land-use class over time and reveals the relationships between different classes [11]. It is expected that, the use of these techniques for analysis of the existing regional land-use changes would help specialists to prepare and implement management plans regarding sustainable developments [12].…”