Falko T. Buschke’s research while affiliated with KU Leuven and other places

Islands are fundamental model systems in ecology, biogeography, and evolutionary biology. However, terrestrial islands, unlike their aquatic counterparts, have received comparatively less attention. Among these land islands, inselbergs (i.e. isolated rock outcrops with diverse lithologies and a modest topographical prominence) stand out as iconic examples distributed worldwide across global biomes. Due to their durable lithology, inselbergs change slowly, persisting for tens of millions of years. In this review, we propose a biological definition for inselbergs that captures three fundamental characteristics of inselbergs from the perspective of biota. These are old age, isolation and the presence of unique microhabitats that are rare or absent in the surrounding matrix, fostering distinct communities often with unique and endemic biota. We synthesise the state of the art and formulate a set of testable hypotheses to deepen our understanding of the origins and maintenance of diversity on inselbergs, which are increasingly exposed to anthropogenic threats. By offering different habitats compared to the surrounding habitat matrix (e.g. moist microhabitats in dryland landscapes and xeric environments in humid tropical landscapes), insel-bergs may allow specific lineages to thrive beyond their typical geographical limits. Particularly in drylands and degraded landscapes, inselbergs may not just provide different habitats but also act as ecological refuges or evolutionary refugia by providing a wider range of potential microhabitats than the surrounding matrix, enhancing resilience and promoting regional biodiversity. The central role of the matrix ensures that the ecological and evolutionary dynamics of inselbergs differ from those of true islands such as oceanic islands. Given that inselberg biota coexist within a terrestrial matrix, interactions between inselberg and matrix populations impact each other significantly. Over evolutionary timescales, matrix species may contract to inselberg refugia, preserving lineages while cycles of isolation and reconnection may drive speciation via a species pump. Although inselberg biodiversity has been studied predominantly from an island biogeography perspective, we argue that depending on the spatial scale, habitat specificity and mobility of the organisms considered, a range of different theories and paradigms can help explain the biogeography and local distribution patterns of different taxonomic and functional groups of inselberg species.

Global restoration is a priority given the onset of the United Nations’ decade for restoration. It is challenging to restore arid lands from mining impacts, especially where topsoil deficits exist. Successful rehabilitation is essential for alternative land use after mining. This bioassay aimed to establish whether and why some combinations of iron ore mine-affected soils and ameliorants are more effective in promoting plant growth than others. We examined the responses of one thousand radishes (Raphanus sativus)to five mine-affected soils and four soil ameliorations (soil improvement using fertiliser and organic matter) over two different seasons (early and late rainy seasons). We found that soil characteristics affected plant production regardless of amelioration and that some soil/amelioration combinations were significantly better than others. Topsoil ameliorated by moderate fertiliser application produced the best results. Waste rock could support germination and plant production when ameliorated with certain organic compost and fertiliser combinations. Untreated mine-affected soils had low to no plant production. Plant responses to the different soil/amelioration combinations were affected by season. Our findings suggest that area-specific bioassay investigations and their results could improve management decisions to achieve rehabilitation targets for mine-affected soils.

Conservation policies often take for granted the importance of protected areas for supplying ecosystem services. The 1st edition of the State of Protected and Conserved Areas in Eastern and Southern Africa report contained limited information on ecosystem services, so for the upcoming 2nd edition we compared statistically 561 standardised economic values of various types of ecosystem services inside and outside of protected areas. We found that data from local and sub-national case-studies in the Ecosystem Service Valuation Database were biased geographically, highlighting major evidence gaps for most of the region. For well-studied countries (Botswana, Ethiopia, Kenya, South Africa, Tanzania, Uganda), the value of ecosystem services varied considerably across different types of services but were - on average - five times higher outside protected areas. This trend was not universal, however, given that opportunities for recreation and tourism tended to be 20 times higher within protected areas. Combined, these findings suggest that conservation authorities across Eastern and Southern Africa (1) prioritise ecosystem service valuation studies; (2) expand the focus of ecosystem service policies to include wider landscapes beyond protected area boundaries; and (3) avoid making generic assumptions about ecosystem services by identifying which types of services are most compatible with the broader goals of protection.

The Sustainable Development Goals (SDGs) represent global development ambitions, but achieving these goals depends on local-level application. Many local governments, especially in countries with emerging economies, lack the capacity and resources to integrate SDGs into municipal planning. The feasibility of local implementation is particularly challenging in areas with rugged topography and international borders, such as the Thabo Mofutsanyana District Municipality, South Africa, into which the city of Phuthaditjhaba falls. Here we explore the suitability of existing spatial biodiversity plans for local application in the six local municipalities within Thabo Mofutsanyana District. We considered four plans related to biodiversity and ecosystem services, including international maps of (1) Key Biodiversity Areas and (2) Strategic Water Source Areas; a national (3) Protected Area Expansion Strategy; and a provincial map of (4) Critical Biodiversity Areas. Although these plans were not designed specifically to meet the SDGs, we show that they can be repurposed to address seven of the 17 SDGs. Next, we summarised the spatial coverage of each plan across the six local municipalities and evaluated the opportunities and shortcomings of using these plans for local application. Our findings guide local officials on the most efficient way to plan for the SDGs using currently available spatial products.

Coal is an important energy resource in South Africa. The environmental sustainability of coal extraction is however questionable. This is especially true for natural water sources, which can be severely degraded by coal mining activities. The impacts of coal mining on water resources include direct, indirect, induced, and cumulative impacts. In this chapter, the authors assess the total impact of coal mining pollution on water bodies in Emalahleni within the eMalahleni-Witbank coalfield of the Mpumalanga Highveld. The effects of land use around Emalahleni on the ecosystem’s natural water purification function were simulated. The simulation allowed the authors to quantify the cumulative impacts of changing rainfall patterns anticipated under climate change, as well as some scenarios of continued ecosystem degradation or restoration. Induced impacts on municipal water supply have also been assessed by summarising water usage data from an Emalahleni household survey. The case study offers a comprehensive overview of the challenges facing the water-energy nexus and demonstrates how integrating the water and energy sectors is essential for securing a more sustainable future.