An assessment of the impact of climate change on plant species richness through an analysis of the Normalised Difference Water Index (NDWI) in Mutirikwi Sub-catchment, Zimbabwe

This study assesses the effects of climate change on vegetative species diversity exploring the usefulness of the Normalised Difference Water Index (NDWI) in predicting spatio-temporal diversity variations. The relationship between species richness and climatic variables of rainfall and temperature is explored based on species data collected from the field over a 3 year period and climate data collected from four local weather stations. Relationship between NDWI and species diversity indices is examined to confirm the usefulness of Remote Sensing in predicting vegetative diversity. The resultant predictive model was used to estimate changes in species richness over a 27 year period (1987-2014). The species diversity data was then regressed with climatic data for the same period. The results show a significant (P<0.05) correlation between species diversity and the two climatic variables. The results also indicate that there is a significant positive (P=0.0001; α=0.05; R2=0.565) relationship between species richness and NDWI. This implies that the NDWI is essential when assessing changes in species diversity over time. The Mann Kendall test revealed a decrease, though not statistically significant, in the rainfall received within the catchment over the period and significant variability. The minimum and maximum temperatures over the period were significantly increasing. These changes in climate variables were matched with a decrease in species richness. Some species tend to be succumbing to the environmental changes influenced by climate change resulting in their changes in phenology, abundance and distribution

Guideline and indicators for Target 6.6 of the SDGs: “Change in the extent of waterrelated ecosystems over time”

This guideline provides supporting information to assist with implementation of monitoring procedures for Target 6.6 indicator, which focuses on protecting and maintaining water-related ecosystems

Contribution of smallholder farmers to food security and opportunities for resilient farming systems

Climate change poses challenges that negatively affect smallholder farmers’ contribution to food security in sub-Saharan Africa. Consequently, countries from this region have the responsibility to reduce green gas emissions and adapt to the changing climate in the agricultural sector through such measures as climate-smart agriculture (CSA). This systematic review provides an overview of the CSA adoption challenges faced by smallholder farmers towards ensuring food security as well as recommendations to upscale CSA practices uptake. The review focuses on smallholder farmers of sub-Saharan Africa. Data collection for formal systematic reviews followed the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. Information was gathered from peer-reviewed articles with no limit to the year of publication. A total of 58 papers from the Web of Science and Scopus databases were included in the analysis. Results reveal that more research efforts need to be exerted towards the very vulnerable Southern Africa. The adoption of innovative agricultural practices should focus on rainwater harvesting and mulching while other CSA practices such as crop diversification and crop rotation show a high number of practices. However, major challenges facing smallholder farmers are financial availability, access to information and farm size. These hinder stallholder farmers’ ability to contribute to food security. As such, authors have recommended policy intervention, knowledge dissemination and capacity building as possible measures to get smallholder farmers on the right path to sustainable food production and CSA practices uptake

Resilience and sustainability of the water sector during the Covid-19 pandemic

The COVID-19 pandemic brought unprecedented socio-economic changes, ushering in a “new (ab)normal” way of living and human interaction. The water sector was not spared from the effects of the pandemic, a period in which the sector had to adapt rapidly and continue providing innovative water and sanitation solutions. This study unpacks and interrogates approaches, products, and services adopted by the water sector in response to the unprecedented lockdowns, heralding novel terrains, and fundamental paradigm shifts, both at the community and the workplace. The study highlights the wider societal perspective regarding the water and sanitation challenges that grappled society before, during, after, and beyond the pandemic

Malaria around large dams in Africa: effect of environmental and transmission endemicity factors.

BACKGROUND:The impact of large dams on malaria has received widespread attention. However, understanding how dam topography and transmission endemicity influence malaria incidences is limited. METHODS:Data from the European Commission's Joint Research Center and Shuttle Radar Topography Mission were used to determine reservoir perimeters and shoreline slope of African dams. Georeferenced data from the Malaria Atlas Project (MAP) were used to estimate malaria incidence rates in communities near reservoir shorelines. Population data from the WorldPop database were used to estimate the population at risk of malaria around dams in stable and unstable areas. RESULTS:The data showed that people living near (< 5 km) large dams in sub-Saharan Africa grew from 14.4 million in 2000 to 18.7 million in 2015. Overall, across sub-Saharan Africa between 0.7 and 1.6 million malaria cases per year are attributable to large dams. Whilst annual malaria incidence declined markedly in both stable and unstable areas between 2000 and 2015, the malaria impact of dams appeared to increase in unstable areas, but decreased in stable areas. Shoreline slope was found to be the most important malaria risk factor in dam-affected geographies, explaining 41-82% (P < 0.001) of the variation in malaria incidence around reservoirs. CONCLUSION:Gentler, more gradual shoreline slopes were associated with much greater malaria risk. Dam-related environmental variables such as dam topography and shoreline slopes are an important factor that should be considered in efforts to predict and control malaria around dams

Prospects of improving agricultural and water productivity through unmanned aerial vehicles

Unmanned Aerial Vehicles (UAVs) are an alternative to costly and time-consuming traditional methods to improve agricultural water management and crop productivity through the acquisition, processing, and analyses of high-resolution spatial and temporal crop data at field scale. UAVs mounted with multispectral and thermal cameras facilitate the monitoring of crops throughout the crop growing cycle, allowing for timely detection and intervention in case of any anomalies. The use of UAVs in smallholder agriculture is poised to ensure food security at household level and improve agricultural water management in developing countries. This review synthesises the use of UAVs in smallholder agriculture in the smallholder agriculture sector in developing countries. The review highlights the role of UAV derived normalised difference vegetation index (NDVI) in assessing crop health, evapotranspiration, water stress and disaster risk reduction. The focus is to provide more accurate statistics on irrigated areas, crop water requirements and to improve water productivity and crop yield

An Assessment of the Impacts of Climate Variability and Change in KwaZulu-Natal Province, South Africa

Rainfall and air temperature variability pose the greatest risk to environmental change. Past trends in rainfall and air temperature facilitate projecting future climate changes for informed policy responses. We used a combination of the normalised difference vegetation index (NDVI) and observed data from 1968 to 2017 to assess changes in rainfall, moisture stress, and air temperature variability over time on bioclimatic regions of KwaZulu-Natal (KZN) Province, South Africa. Indicators used included consecutive dry days (CDDs), consecutive wet days (CWDs), very heavy rainfall days (R20), monthly maximum daily maximum air temperature (TXx), monthly minimum daily minimum air temperature (TNn), the total number of rainfall days, and monthly air temperature averages. Trends in rainfall and moisture stress are notable in different bioclimatic regions across the province. However, these trends are diverse, in general, and spatially different across and within the bioclimatic regions. Further, related rainfall indicators do not respond in the same way as would be expected. Air temperature trends were consistent with global trends and land–air temperature anomalies. Although daytime air temperatures showed a positive trend, extreme air temperature events and increases are predominant in inland regions. Night-time air temperatures showed an upward trend in most stations across KZN. Local weather-and-climate related characteristics are evolving due to climatic variability and change. The study shows that changes in climatic activities are detectable at a local level from existing historical weather data; therefore, adaptation strategies should be contextualised to respond to local and area-specific challenges

Migration under Climate Change in Southern Africa: A Nexus Planning Perspective

Population increase is exacerbating resource insecurities due to increased demand for already depleted resources. Coupled with climate change, they are the main drivers of both intra-(rural-urban and urban-urban) and inter-migration (from one country to the other). We carried out a systematic review of literature, focusing on available options to ensure water and food security, as well as improve the socio-economic environment, highlighting the drivers of migration in southern Africa. The aim was to develop informed adaptation strategies and build resilience in the advent of accelerated migration. We developed a migration conceptual framework based on the nexus between water, food and socio-economic interlinkages. Urban areas in southern Africa are under immense pressure to accommodate climate refugees from resource stressed rural areas, a situation that is impacting on agricultural production. Most urban areas are exceeding their ecological thresholds to support the built environment, causing some socio-ecological challenges. Nexus planning can inform adaptation planning on permissible migration that are aligned with regional goals such as regional integration, poverty reduction and improved livelihoods. This would also contribute to the region's achievements of the Sustainable Development Goals. Furthermore, through the identification of synergies and trade-offs, nexus planning can inform regional adaptation strategies for positively managing migration leading to sustainable outcomes

Prospects of orphan crops in climate change.

Orphan crops can contribute to building resilience of marginal cropping systems as a climate chnage adaptation strategy. Orphan crops play an important role in global food and nutrition security, and may have potential to contribute to sustainable food systems under climate change. Owing to reports of their potential under water scarcity, there is an argument to promote them to sustainably address challenges such as increasing drought and water scarcity, food and nutrition insecurity, environmental degradation, and employment creation under climate change. We conducted a scoping review using online databases to identify the prospects of orphan crops to contribute to (1) sustainable and healthy food systems, (2) genetic resources for future crop improvement, and (3) improving agricultural sustainability under climate change. The review found that, as a product of generations of landrace agriculture, several orphan crops are nutritious, resilient, and adapted to niche marginal agricultural environments. Including such orphan crops in the existing monocultural cropping systems could support more sustainable, nutritious, and diverse food systems in marginalised agricultural environments. Orphan crops also represent a broad gene pool for future crop improvement. The reduction in arable land due to climate change offers opportunities to expand the area under their production. Their suitability to marginal niche and low-input environments offers opportunities for low greenhouse gas (GHG) emissions from an agro-ecosystems, production, and processing perspective. This, together with their status as a sub-set of agro-biodiversity, offers opportunities to address socio-economic and environmental challenges under climate change. With research and development, and policy to support them, orphan crops could play an important role in climate-change adaptation, especially in the global south