Evaluating urban greening scenarios for urban heat mitigation: a spatially explicit approach.

Urban green infrastructure, especially trees, are widely regarded as one of the most effective ways to reduce urban temperatures in heatwaves and alleviate the adverse impacts of extreme heat events on human health and well-being. Nevertheless, urban planners and decision-makers are still lacking methods and tools to spatially evaluate the cooling effects of urban green spaces and exploit them to assess greening strategies at the urban agglomeration scale. This article introduces a novel spatially explicit approach to simulate urban greening scenarios by increasing the tree canopy cover in the existing urban fabric and evaluating their heat mitigation potential. The latter is achieved by applying the InVEST urban cooling model to the synthetic land use/land cover maps generated for the greening scenarios. A case study in the urban agglomeration of Lausanne, Switzerland, illustrates the development of tree canopy scenarios following distinct spatial distribution strategies. The spatial pattern of the tree canopy strongly influences the human exposure to the highest temperatures, and small increases in the abundance of tree canopy cover with the appropriate spatial configuration can have major impacts on human health and well-being. The proposed approach supports urban planning and the design of nature-based solutions to enhance climate resilience.

An ecosystem service perspective on urban nature, physical activity, and health.

Nature underpins human well-being in critical ways, especially in health. Nature provides pollination of nutritious crops, purification of drinking water, protection from floods, and climate security, among other well-studied health benefits. A crucial, yet challenging, research frontier is clarifying how nature promotes physical activity for its many mental and physical health benefits, particularly in densely populated cities with scarce and dwindling access to nature. Here we frame this frontier by conceptually developing a spatial decision-support tool that shows where, how, and for whom urban nature promotes physical activity, to inform urban greening efforts and broader health assessments. We synthesize what is known, present a model framework, and detail the model steps and data needs that can yield generalizable spatial models and an effective tool for assessing the urban nature-physical activity relationship. Current knowledge supports an initial model that can distinguish broad trends and enrich urban planning, spatial policy, and public health decisions. New, iterative research and application will reveal the importance of different types of urban nature, the different subpopulations who will benefit from it, and nature's potential contribution to creating more equitable, green, livable cities with active inhabitants.

Distant regions underpin interregional flows of cultural ecosystem services provided by birds and mammals.

Ecosystem service assessments rarely consider flows between distant regions. Hence, telecoupling effects such as conservation burdens in distant ecosystems are ignored. We identified service-providing species for two cultural ecosystem services (existence and bequest, and birdwatching) and two receiving, i.e. benefitting, regions (Germany, the Netherlands). We delineated and analysed sending, i.e. service-providing, regions on a global scale. The proportion of service-providing species with distant habitats was higher for birdwatching (Germany: 58.6%, Netherlands: 59.4%), than for existence and bequest (Germany: 49.3%, Netherlands: 57.1%). Hotspots of sending regions were predominantly situated in tropical and subtropical grasslands, savannas and shrublands and were significantly more threatened and poorer than the global mean. Hotspot protection levels for flows to Germany were higher than the global mean, and lower for the Dutch hotspots. Our findings increase understanding on how distant regions underpin ecosystem services and necessitate interregional assessment as well as conservation efforts.

Spatial prioritisation for conserving ecosystem services: comparing hotspots with heuristic optimisation.

CONTEXT: The variation in spatial distribution between ecosystem services can be high. Hence, there is a need to spatially identify important sites for conservation planning. The term 'ecosystem service hotspot' has often been used for this purpose, but definitions of this term are ambiguous. OBJECTIVES: We review and classify methods to spatially delineate hotspots. We test how spatial configuration of hotspots for a set of ecosystem services differs depending on the applied method. We compare the outcomes to a heuristic site prioritisation approach (Marxan). METHODS: The four tested hotspot methods are top richest cells, spatial clustering, intensity, and richness. In a conservation scenario we set a target of conserving 10 % of the quantity of five regulating and cultural services for the forest area of Telemark county, Norway. RESULTS: Spatial configuration of selected areas as retrieved by the four hotspots and Marxan differed considerably. Pairwise comparisons were at the lower end of the scale of the Kappa statistic (0.11-0.27). The outcomes also differed considerably in mean target achievement, cost-effectiveness in terms of land-area needed per unit target achievement and compactness in terms of edge-to-area ratio. CONCLUSIONS: An ecosystem service hotspot can refer to either areas containing high values of one service or areas with multiple services. Differences in spatial configuration among hotspot methods can lead to uncertainties for decision-making. This also has consequences for analysing the spatial co-occurrence of hotspots of multiple services and of services and biodiversity.