T he Convention on Biological Diversity (CBD) sets the policy framework for biodiversity conservation and sustainable use through the commitments of 195 countries and the European Union. The Strategic Plan for Biodiversity 2011-2020 included Aichi Biodiversity Target 12, which set the goal for 2020 of preventing the extinction of known threatened species and improving and sustaining their conservation status. Despite government commitments and successful efforts for certain species 1 , the overall extinction risk continues to increase, and widespread implementation shortfalls will prevent Target 12 from being met 2 . A new global framework with revised goals and targets is currently being negotiated, which places the stabilization and restoration of species' populations as an outcome goal for 2030, as a stepping stone towards the CBD's 2050 Vision 3,4 .
Increases in woody plant cover in savanna grassland environments have been reported on globally for over 50 years and are generally perceived as a threat to rangeland productivity and biodiversity. Despite this, few attempts have been made to estimate the extent of woodland increase at a national scale, principally due to technical constraints such as availability of appropriate remote sensing products. In this study, we aimed to measure the extent to which woodlands have replaced grasslands in South Africa's grassy biomes. We use multiseason Landsat data in conjunction with satellite L-band radar backscatter data to estimate the extent of woodlands and grasslands in 1990 and 2013. The method employed allows for a unique, nationwide measurement of transitions between grassland and woodland classes in recent decades. We estimate that during the 23-year study period, woodlands have replaced grasslands over ~57 000 km and conversely that grasslands have replaced woodlands over ~30 000 km , a net increase in the extent of woodland of ~27 000 km and an annual increase of 0.22%. The changes varied markedly across the country; areas receiving over 500 mm mean annual precipitation showed higher rates of woodland expansion than regions receiving <500 mm (0.31% yr and 0.11% yr , respectively). Protected areas with elephants showed clear loss of woodlands (-0.43% yr ), while commercial rangelands and traditional rangelands showed increases in woodland extent (>0.19% yr ). The woodland change map presented here provides a unique opportunity to test the numerous models of woody plant encroachment at a national/regional scale.
Intensive pastoralism with goats transforms semiarid thicket in the Eastern Cape, South Africa from a dense vegetation of tall shrubs to an open landscape dominated by ephemeral grasses and forbs. Approx. 800 000 ha of thicket (which prior to the introduction of goats had a closed canopy and a Portulacaria afra Jacq. component) have been transformed in this manner. Ecosystem C storage in intact thicket and loss of C due to transformation were quantified. Carbon storage in intact thicket was surprisingly high for a semiarid region, with an average of 76 t C ha −1 in living biomass and surface litter and 133 t C ha −1 in soils to a depth of 30 cm. Exceptional C accumulation in thicket may be a result of P. afra dominance. This succulent shrub switches between C 3 and CAM photosynthesis, produces large quantities of leaf litter (approx. 450 g m −2 year −1 ) and shades the soil densely. Transformed thicket had approx. 35% less soil C to a depth of 10 cm and approx. 75% less biomass C than intact thicket. Restoration of transformed thicket landscapes could consequently recoup more than 80 t C ha −1 .
In 2014, the International Union for Conservation of Nature adopted the Red List of Ecosystems (RLE) criteria as the global standard for assessing risks to terrestrial, marine, and freshwater ecosystems. Five years on, it is timely to ask what impact this new initiative has had on ecosystem management and conservation. In this policy perspective, we use an impact evaluation framework to distinguish the outputs, outcomes, and impacts of the RLE since its inception. To date, 2,821 ecosystems in 100 countries have been assessed following the RLE protocol. Systematic assessments are complete or underway in 21 countries and two continental regions (the Americas and Europe). Countries with established ecosystem policy infrastructure have already used the RLE to inform legislation, land‐use planning, protected area management, monitoring and reporting, and ecosystem management. Impacts are still emerging due to varying pace and commitment to implementation across different countries. In the future, RLE indices based on systematic assessments have high potential to inform global biodiversity reporting. Expanding the coverage of RLE assessments, building capacity and political will to undertake them, and establishing stronger policy instruments to manage red‐listed ecosystems will be key to maximizing conservation impacts over the coming decades.
The loss of natural habitat resulting from human activities is the principal driver of biodiversity loss in terrestrial ecosystems globally. Metrics of habitat loss are monitored at national and global scales using various remote sensing based land-cover change products. The metrics go on to inform reporting processes, biodiversity assessments, land-use decision-making and strategic planning in the environmental and conservation sector. We present key metrics of habitat loss across South Africa at national and biome levels for the first time. We discuss the spatial patterns and trends, and the implications and limitations of the metrics. Approximately 22% of the natural habitat of South Africa has been lost since the arrival of European settlers. The extent and the rate of habitat loss are not uniform across South Africa. The relatively mesic Grassland, Fynbos and Indian Ocean Coastal Belt biomes have lost the most habitat, while the arid Nama-Karoo, Succulent Karoo and Desert have lost the least. Rates of loss increased across all biomes in recent years (2014–2018), indicating that the historical drivers of change (i.e. expansion of croplands, human settlements, plantation forestry and mining) are intensifying overall. We should caution that the losses we report are conservative, because the land-cover change products do not capture degradation within natural ecosystems. Preventing widespread biodiversity losses and securing the benefits we derive from biodiversity requires slowing and preventing further habitat degradation and loss by using existing land-use planning and regulatory tools to their full potential.
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