Browsing by Author "Chisadza, Bright"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Evaluating the spatiotemporal dynamics of agrometeorological droughts in semi-arid Gwayi agroecosystems (1990–2020) using multiple indices
    (Taylor & Francis, 2024-10-10) Chisadza, Bright; Gwate, Onalenna; Musinguzi, Simon Peter
    Climate variability poses a significant threat to smallholder farmers in the Gwayi catchment, Zimbabwe. This study investigated the spatiotemporal dynamics of agrometeorological droughts from 1990 to 2020 using the Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), Vegetation Condition Index (VCI), and Vegetation Health Index (VHI). The triangulation of these indices provided a comprehensive understanding of drought dynamics. Severe to extreme drought events were identified in 1995, 1998, 2005, 2016, 2018, and 2020, while moderate droughts were consistently detected across all indices. Favourable conditions were observed in 2000 and 2006. A strong positive correlation (r¼0.88) between VHI and VCI suggests their similar effectiveness in reflecting vegetation health. In contrast, moderate correlations between VHI and SPI (r ¼0.30), VHI and SPEI (r¼0.39), VCI and SPI (r¼0.28), and VCI and SPEI (r¼0.40) indicate that these indices capture complementary information, reflecting not only precipitation deficits but also the impacts of temperature, soil moisture, and land cover changes. The SPI and SPEI displayed a strong positive correlation (r ¼0.78), aligning in their sensitivity to precipitation and evapotranspiration. Spatial analysis revealed a pronounced north-south drought gradient, with the southwestern region being particularly vulnerable, underscoring the need for targeted interventions.
  • Thumbnail Image
    Item
    Review of the land use and climate change impact assessments in semi-arid ecosystems in Africa: Opportunities and challenges
    (Water and Environmental Sustainability, 2023-12) Chisadza, Bright; Musinguzi, Simon Peter; Gwate, Onalenna; Malinga, Wayne
    Despite the existing literature on climate variability (CV) and land use change (LUC) impact assessments, understanding their effectiveness in semi-arid regions remains challenging. This review aims to assess the effectiveness of CV and LUC impact assessments in guiding adaptation options for smallholder farmers in semi-arid ecosystems and associated challenges and opportunities. We conducted a systematic literature review, primarily using Google Scholar, to examine the impact of LUC and CV in African semi-arid ecosystems. We employed Vos Viewer to analyze the relationships among the identified sources. Our findings reveal that current assessment approaches often fall short in capturing the intricate interactions within semi-arid ecosystems. These assessments frequently emphasize biophysical productivity, employ reductionist modeling methods, and neglect the social, economic, and adaptive aspects of these systems. Our review underscores the importance of integrating CV and LUC in impact assessments. While a majority of studies concentrate on CV adaptation (26%), they often overlook the pivotal role of LUC and their interplay with climate impacts. Only a small fraction (2%) integrates CV and LUC in impact assessments. Assessing the benefits of CV and LUC impact assessments presents mixed results, particularly for smallholder farmers. While global and regional benefits are discernible, quantifying these advantages at the local smallholder farmer level remains challenging due to diversified land use and small-scale operations. This highlights the need for localized studies addressing the specific challenges confronting smallholder farmers in semi-arid regions. To enhance assessments effectiveness, we recommend for more interdisciplinary research and the application of a complex systems approach, integrating GIS and remote sensing.