Changes in land use and land cover (LULC) attributed to anthropogenic activities are one of the fundamental drivers of environmental changes at the local, regional and global levels. These changes continue to threaten the capacity of the ecosystems to function and provide environmental goods and services and the ability to sustain the livelihoods of rural communities. Therefore, a critical understanding of LULC patterns and dynamics is crucial for predicting future LULC patterns and changes and formulation of appropriate policies, strategies and interventions for sustainable management of natural resources. Dedza district like any other district in Malawi has experienced rapid LULC changes over the past decades. However, knowledge about LULC changes that occur, where and when they occur and the rates at which they occur is not well documented. Equally important is the examination of the drivers and processes that cause these changes and the extent to which these LULC changes have impacted on natural resources and rural livelihoods in the studied area. As such, this remains a critical challenge that needs to be addressed in order to achieve sustainable natural resource management and community development. This study aimed to investigate the nature of LULC changes that have taken place between 1991 and 2015, drivers attributing to these changes and their impacts of these changes on the natural resources in Dedza district of Malawi. The study used a mixed-method approach consisting of remote sensing and Geographic Information System (GIS)-based analysis, model simulations, focus-group discussions, key informant interviews, and semi-structured interviews covering 586 households. An overall accuracy of the classification achieved for the classified images was 91.86%. GIS-based analysis of remotely sensed data revealed that the areas under agricultural land, forest area, wetlands, water bodies drastically decreased from 71.3% (267,977.43 ha), 24.53% (9,939.15 ha), 0.96% (3,626.73 ha), 0.37% (1,380.60 ha) in 1991 to 69.41% (260,879.31 ha), 1.66% (6,237.63 ha), 0.71% (2,680.29 ha) and 0.24% (899.55 ha) in 2015. On the contrary, barren land and built-up areas substantially increased from 24.53% (92,185.38 ha) and 0.20% (761.67 ha) in 1991 to 25.85% (97,174.62 ha), 2.13% (7,999.56 ha) in 2015 respectively. Significant differences were found among the interviewed households in perceptions regarding LULC changes taken place in the studied landscape and distance to different infrastructures such as main roads, health centres, schools, and towns (p < 0.001). The results of the household surveys indicated that the local communities were aware of the LULC dynamics and validated the observed changes. Firewood collection, charcoal production, population growth, and poverty were identified as the key drivers of observed LULC changes in the study area. Local communities perceived that LULC changes led to a decline in agricultural land (57.3%, n = 586), crop production (82.8%, n = 586) and forest cover (87.4%, n = 586) and an increase in the distance to forest resources (50.7%, n = 586). These changes exposed rural households to major shocks such as drought, floods, food shortage, loss/damage of crops and death of household members. In order to address these shocks, communities were engaged in short-term strategies such as piecework, receiving aid from government and NGOs, receiving unconditional aid from relatives, relying on their own savings and credits. The simulation results using the CA-Markov model showed that water bodies, barren land and built-up areas will increase while agricultural land, wetlands and forest land will substantially decrease by 2025 and 2035. The undesired LULC changes, patterns and impacts observed in this study, however, pose a big threat and risk to the sustainable management of natural resources and rural livelihoods survival. Hence, the need for urgent attention by the natural resource managers, planners, researchers and decision-makers. The results found in this study are deemed useful in guiding planners and decision-makers in the field of land management and policy development towards a more sustainable natural resource management strategy in Dedza district. Results found in this study could also inform decision-making in other districts of similar settings. Thus, results of the study are expected to support decision-makers and planners in the design and implementation of holistic, tenable and coherent and sustainable development policies/strategies/ guidelines for effective natural resource management. / Thesis (PhD)--University of Pretoria, 2019. / Geography, Geoinformatics and Meteorology / PhD / Unrestricted

Karst rocky desertification (KRD) is one kind of severe environmental problem existing in southwest of China. Reveal KRD condition is vital to solve the problem. A way to address the problem is by identifying KRD areas, so that policy-makers and researchers may get a better view of the issue and know where the areas affected by the problem are located. The study area is called Puding which is a county located in the central part of Guizhou province. Based on Landsat data, by using GIS and RS techniques, KRD information of Puding was extracted. Furthermore, the study monitored decades of change of the environmental problem in Puding and predicted possible condition in the future. Other researchers and decision makers may get a better view of the issue from the study results. In addition to Landsat data, other used data includes: ASTER Global digital elevation model data, Modis data, Google Earth data and other thematic maps. In the study, expert classification system and spectral features based model two methods were applied to extract KRD information and compare with each other. Their classified rules were taken from previous studies separately. Necessary preprocessing procedures such as atmospheric correction and geometrical correction were performed before extraction. After extraction relevant results were evaluated and analyzed. Predictions were made by cellular automata Markov module. Based on extracted KRD results, the distribution, percentage, change, and prediction of KRD conditions in Puding were presented. The results of the accuracy evaluation showed that the spectral features based model had acceptable performance. However, the KRD results extracted by expert classification system method were poor. The extracted KRD results, including KRD maps and the prediction map, both indicated that KRD areas in Puding were decreased from 1993 (spring) to 2016 (spring) and suggested to pay more attention to KRD areas changes with the seasons

Land use and land cover changes (LULCC) including deforestation for agricultural land and others are elements that contribute on global environmental change. Therefore understanding a trend of these changes in the past, current, and future is important for making proper decisions to develop in a sustainable way. This study analyzed land use and land cover (LULC) changes over time for Tuy Duc district belonging to Dak Nong province based on LULC maps classified from a set of multidate satellite images captured in year 2003, 2006, 2009, and 2013 (SPOT 5 satellite images). The LULC spatio-temporal changes in the area were classified as perennial agriculture, cropland, residential area, grassland, natural forest, plantation and water surface. Based on these changes over time, potential LULC in 2023 was predicted using Cellular Automata (CA)–Markov model. The predicted results of the change in LULC in 2023 reveal that the total area of forest will lose 9,031ha accounting of 50% in total area of the changes. This may be mainly caused by converting forest cover to agriculture (account for 28%), grassland (12%) and residential area (9%). The findings suggest that the forest conversion needs to be controlled and well managed, and a reasonable land use plan should be developed in a harmonization way with forest resources conservation. / Thay đổi sử dụng đất và thảm phủ (LULCC) bao gồm cả việc phá rừng để phát triển nông nghiệp và vì các mục đích khác là tác nhân đóng góp vào biến đổi môi trường toàn cầu. Vì vậy hiểu biết về khuynh hướng của sự thay đổi này trong quá khứ, hiện tại và tương lai là quan trọng để đưa ra những quyết định dúng đắn để phát triển bền vững. Nghiên cứu đã phân tích LULCC trong thời gian qua dựa vào các bản đồ sử dụng đất và thảm phủ (LULC) đã được phân loại từ một loạt ảnh vệ tinh đa phổ được thu chụp vào năm 2003, 2006, 2009 (ảnh SPOT 5). Những thay đổi LULC theo thời gian và không gian trong khu vực được phân loại thành đất nông nghiệp với cây dài ngày, cây ngắn ngày, thổ cư, trảng cỏ cây bụi, rừng tự nhiên, rừng trồng và mặt nước. Dựa trên sự thay đổi này theo thời gian, LULC tiềm năng cho năm 2023 đã được dự báo bằng cách sử dụng mô hình CAMarkov. Kết quả dự báo LULCC năm 2023 đã cho thấy tổng diện tích rừng bị mất khoảng 9,031 ha chiếm 50% trong tổng số diện tích thay đổi. Điều này chủ yếu là do chuyển đổi từ rừng tự nhiên sang canh tác nông nghiệp (chiếm 28%), trảng cỏ cây bụi (12%) và khu dân cư (9%). Kết quả cho thấy việc chuyển đổi rừng cần phải được kiểm soát và quản lý tốt và một kế hoạch sử dụng đất hợp lý cần được xây dựng trong sự hài hòa với bảo tồn tài nguyên rừng.

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