Professor Abel Ramoelo, the Director for the Centre of Environmental Studies housed at the Department of Geography, Geoinformatics and Meteorology, University of Pretoria was invited to give a keynote address at the 56th Grassland Society of Southern Africa (GSSA) Congress held virtually from the 26 – 30th July 2021. The presentation titled Rangeland assessments and monitoring in the ever-changing environmental conditions: current earth observation and geoinformation science applications, was motivated by the unprecedented challenges rangelands are facing, while they are very critical for livestock production, and biodiversity conservation. It is evident that global environmental changes including climate change and land use change threaten livelihoods and the resilience of rangeland ecosystem services. Specifically, anthropogenic factors leading to these changes are caused by the increasing human population, settlement expansions or urbanization, agricultural intensification both for crops and livestock production. On the other hand, future climate projections show higher frequency of droughts and erratic rainfall. There is clearly a need to effectively and efficiently monitor the extent and condition of our rangelands. To augment the conventional way of data collection, remotely sensed data offers opportunities to assess and monitor rangelands, through;
- Comprehensive spatial representation of the rangelands;
- Higher frequency of the data;
- Covering wider of areas;
- Probable cost reduction;
- Acquisition of data in inaccessible area, e.g., rugged terrains;
- Non-destructive and regular way for data collection, and
- Instant information sharing to decision makers, i.e., planners, managers and policy makers.
The address showcased the results from various remote sensing studies to assess and monitor rangeland essential variables such as grass quality (nutrient concentrations, and species composition), and quantity (biomass, leaf area index, productivity) at multiple scales. The talk further elucidated the use of remote sensing-based vegetation indices to assess the extent to which drought and land degradation are affecting our rangelands. The examples of rangeland products within and around protected areas derived using a suite of remote sensing data at multiple scales in the Savanna and Grassland Biome were presented. Remote sensing provides avenue to map and monitor these essential variables for rangelands using the optical (Landsat, Sentinel-2 and MODIS) and active (Sentinel-1) domain effectively and efficiently. These successes are realized, when remote sensing data are combined with field data, through the suite of parametric and non-parametric modelling tools, i.e., from classical regression to machine learning techniques. Grass quality and quantity information can be integrated into the rangeland monitoring tool, poised to provide actionable information to inform decision-making processes by farmers, planners, managers and policymakers to safeguard our rangelands.
The department of Geography, Geoinformatics and Meteorology prepares its students to employ these various techniques to solve several environmental issues and challenges, such as those facing South African rangelands today.
Pictures: 1) Professor Ramoelo's keynote address advert; 2) rangelands at the Golden Gate Highland National Park (GGHNP)