Peta Brom

Green Infrastructure (GI) connects across a city's urban fabric and exhibits multiple meanings. It inevitably ties to questions about environmental justice. In South Africa, the historical legacy of colonialism and apartheid has left deep scars and the fragmentation of people and places. The justice issues surrounding urban GI are many, complex and unpredictable. They include insecurity, contested access to urban parks, differing perceptions of equity, contested ownership of urban vegetation, and alienation mediated local community involvement. In this systematic review, we analyze 72 scientific publications connecting urban GI and environmental justice in South Africa to identify current research trends. Using the conceptual frame of environmental justice, we structure our analysis around the commonly-used dimensions of distribution, process, and recognition, with added attention to governance. Our review shows that food security, distributional equity, and physical access to urban green space are dominant, with similarities in the spatial and temporal scales of investigation. Environmental justice studies and political ecology are comparable, and we argue that 1) Research on GI access should follow a more nuanced and rights-based approach, 2) a stronger ecological and climatic/biophysical perspective would be valuable, and 3) integrating landscape designs could uncover more actionable and transformative potential. Common across these three avenues of research is a need to embrace more interdisciplinary, participatory, anticipatory, and dynamic thinking across a broader range of scales.

Rapid urbanization is projected for African cities at the cost of urban green space, which could jeopardize biodiversity and human benefits. Studies focusing specifically on human–green space relationships in the Global South are lacking, and the validity of extrapolating results from studies in the Global North remains questionable and cannot provide local context-specific design solutions. This study combines methods and perspectives from ecology and human geography with landscape design to better understand the benefits for biodiversity and people derived from unmanaged green spaces in the City of Tshwane, South Africa. Based on empirical data from two unmanaged green space areas in disadvantaged communities, we identify benefits for biodiversity and people and define guidelines for inclusive trans-disciplinary interventions. We combine information from a vegetation survey, a community survey of 200 respondents and a rapid assessment of multifunctional benefit provision to formulate in holistic landscape design proposals. We show that the sites have biodiversity value and provide habitat for > 169 different plant species, including protected species, and smaller wildlife. Residents use the spaces for utility, passive and active leisure, and > 76% of residents benefit from the use of these spaces. However, the integrity and provision of benefits from green spaces are threatened by pollution, safety concerns, biological invasions, and land conversion. Context-specific designs could be developed by merging methods across disciplines and involving local stakeholders to integrate the multifunctionality of socioecological benefits into landscape interventions. Collaboration across ecology, human geography and landscape design generates multifunctional perspectives of unmanaged green spaces that consider benefits for biodiversity and disadvantaged communities.

Converting road verges and Public Open Space (POS) to floral-rich resources is an important strategy for supporting populations of urban pollinators. One of the ways this can be achieved is through adjusting mowing schedules, either with a “delayed start” after the end of winter, or a reduction in mowing frequency. In Mediterranean climate ecosystems with mild, wet winters, plant growth continues through the winter season and the definition of a “delayed start” is unclear. This study sought to identify a strategic period for the suspension of mowing activities in a city in South Africa with a Mediterranean climate. It estimated the duration of the flowering to seed-broadcast season of 20 species of native geophytes. Observations were made of phenological status from bud to seed broadcast in ten city parks in Cape Town during the austral spring flowering seasons of 2019 and 2020 (August – December). The Underhill and Zucchini (1988) Moult Model was employed to estimate the duration of the flowering season. Model results showed that mowing should stop in the second week of August and should not resume until the beginning of November in the study context. The results are discussed against the relative biodiversity contribution that different parks and verges make and the potential conflicts with the utility objectives of urban society.

Multifunctional green infrastructure, a key component of compact sustainable cities, is challenged by the pressures associated with rapid urbanization. In this paper, we present a method that uses remote sensing, GIS modeling and stakeholder engagement to produce a decision support tool that communicates the availability and need for green infrastructure benefits. The case study presented is the City of Tshwane, South Africa, a Global South city facing rapid urbanization. We found that this method of mapping green infrastructure benefits can provide simultaneous oversight on multiple objectives for green infrastructure, including climate change adaptation, biodiversity, and equitable distribution of urban green space. We found that low-scoring benefit areas occur in dense urban areas where small-scale nature-based solutions or rehabilitation activities are required. Moderate benefit scores occurred in parts of the city that are vulnerable to urban expansion and densification activities, warranting the careful planning of green infrastructure provision, and that moderate-to-high-scoring areas can be protected as conservation areas. The results are discussed in terms of the role of decision support tools for urban planning practice. Composite indexes can provide important guidance to decision-makers involved in spatial planning and urban upgrading and expansion activities.

Background: Urban landscapes present an important opportunity for pollinator conservation, but little is known about the status and distribution of pollinator populations in urban habitats in Africa. This represents a major gap in the development of a global understanding of urban pollinators – particularly from the rapidly urbanising context. This study uses a speciose clade of flower-visiting beetles (Coleoptera: Scarabaeidae: Hopliini) to explore patterns of pollinator distribution in a major metropolitan area in South Africa. Objectives: We investigated community composition across gradients of urban intensity (defined according to the percentage of soil-sealing within 1 km² of each sampling location) and socio-economic status to determine pollinator responses to these urban landscape effects. Methods: A selection of 142 sites were surveyed twice in the austral spring seasons of 2018 and 2019. Data were collected on habitat structure, flower diversity, and pollinator diversity. Results: The study found that different feeding guilds of monkey beetles favoured different levels of urban intensity and that beetle richness significantly correlated with flower richness. It did not, however, correlate with diversity indicating that abundance is less impacted than the number of species present. Monkey beetles with moderate sensitivity to urban intensity benefitted from the presence of preferred species of flowers. Conclusion: Overall, the findings demonstrate the importance of plant community assemblage in supporting urban monkey beetles. We recommend landscaping with preferred flower species in urban parks to support urban pollinators.

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.

Globally insects are declining, but some guilds of pollinators are finding refuge in urban landscapes. The body of knowledge on urban pollinators is relatively mature, which means it is now possible to begin to make generalization. Unfortunately, studies do not represent climatic regions evenly and there is a gap in research from the African continent. This study aimed to address some of the gaps on urban pollination knowledge in South Africa and to identify opportunities to improve urban habitats for pollinators. We reviewed the international literature on urban pollinators and the South African literature on pollinators with a landscape ecology focus, drawing on literature with an emphasis on agricultural and ecosystem services. The findings show that some taxa (e.g. large-bodied, cavity nesting bees) will exploit urban environments increasing in abundance with urban intensity. Moderately sensitive taxa (such as small-bodied, ground-nesting bees) take advantage of urban environments only if local habitats are supportive of their needs for resource provision and habitat connectivity. The South African urban poor rely on pollination services for subsistence agriculture and the reproduction of wild-foraged medicines and food. Potential interventions to improve habitat quality include strategic mowing practices, conversion of turf-grass to floral rich habitats, scientific confirmation of lists of highly attractive flowers, and inclusion of small-scale flower patches throughout the urban matrix. Further research is needed to fill the Africa gap for both specialized and generalized pollinators (Diptera, Halictids, Lepidoptera and Hopliini) in urban areas where ornamental and indigenous flowering plants are valued.

Urban ecosystems are increasingly viewed as an important component within strategies for wildlife conservation but are shaped as much by natural systems as they are by social and political processes. At the garden scale, attitudes and preferences govern design and maintenance choices including the decision to encourage or discourage specific faunal presence. At the global scale, charismatic taxa that are well-liked attract more conservation funding and volunteer stewardship. Amphibians are a class of animals that are both loved and loathed making them a suitable subject for comparing and unpacking the drivers of preference and attitudes towards animals. We conducted a mixed methods survey of 192 participants in three adjacent neighbourhoods in Cape Town, South Africa. The survey included both quantitative and qualitative questions which were analysed thematically and used to explain the quantitative results. The results revealed that attitudes formed during childhood tended to be retained into adulthood, were shaped by cultural norms, childhood experiences and the attitudes of primary care-givers. The findings are significant for environmental education programmes aimed at building connectedness to nature and biophilic values.