Research

MAPPING AND MONITORING ECOLOGICAL CONDITION IN SOUTH AFRICA

Declining ecological condition, also known as land degradation, has been recognised globally as a growing environmental concern due to factors like overgrazing, bush encroachment, invasive species, climate change, and altered fire regimes. However, unlike land-cover change mapping, which is relatively easy to do using remote sensing, the mapping of ecological condition is far more challenging. This is largely because ecological condition is determined by the interplay of various aspects of ecosystem structure, function and composition, which in themselves may be difficult to map. Despite these challenges, mapping ecological condition is essential to understanding the extent of the issue so that decision-makers, planners, and researchers can make informed decisions regarding the sustainable use of ecosystems and conservation thereof to prevent further degradation and implement restoration.

The Ecological Condition Mapping component of the Spatial Biodiversity Assessment Planning and Prioritisation (SBAPP) project in southern Africa is developing national spatial databases of ecological condition for South Africa, Namibia, Mozambique, and Malawi. Our approach aligns with guidelines established by the IUCN Red List of Ecosystems and involves extensive use of remotely sensed layers, but expert knowledge is also essential for contextual (often ecosystem-specific) interpretation of these layers.

THE IMPACT OF CLIMATE CHANGE ON NATURE-BASED SOLUTIONS

TOWARDS EQUITABLE & SUSTAINABLE NATURE-BASED SOLUTIONS project

Nature-based solutions (NbS) are underpinned by assemblages of plant species. Plant species chosen for use in today’s NbS projects and programmes are based on existing assemblages growing under current climate conditions. However, likely changes in climate conditions should be accounted for in existing NbS efforts used for climate adaptation and mitigation. To improve the sustainability of NbS approaches, we investigated how the composition of plant species assemblages underpinning existing NbS may or may not change under climate change in southern Africa. We specifically looked at the following NbS types:

misguided afforestation using alien species,
misguided afforestation using native species,
agroforestry using alien species (146 species),
agroforestry using native species (162 species), and
restoration using native species

We used species distribution modelling using maximum entropy (MaxEnt) (a machine learning correlative approach) to estimate habitat suitability for these plant species based on relationships with environmental and climate predictors. We fitted MaxEnt models using the base current climate conditions (1°C of global warming) and projected species’ distributions using future climate conditions expected at 1.5°C, 2°C, 3°C and +4°C of global warming.

But from our plant species modelling, we found that, between current climate conditions and a future warmer climate of 2°C of global warming, many areas across southern Africa are predicted to experience a high turnover (10% to ~20%) of plant species. The patterns of this turnover vary greatly across the region, and present different challenges and opportunities for different NbS types.

THE IMPACT OF CLIMATE CHANGE ON NATURE-BASED SOLUTIONS

The overarching aim of the EU-funded ALBATROSS project is to accelerate climate adaptation in Sub-Saharan Africa by co-creating with local and national actors feasible and effective policy recommendations for adaptation in several Sub-Saharan African (SSA) countries.

The project focuses on seven "hubs" across the continent and these are the focus areas for my research as part of this project. I am developing species distribution models to represent ecosystem functions that mitigate the impacts of climate change. These will be incorporated in a larger climate risk analysis for each of the hubs.

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