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Recently published green infrastructure, nature-based solutions, and ecosystem disservices (ED) literature have focused primarily on the supply of urban regulating and cultural ecosystem services (ES). Other literature on urban and peri-urban agriculture has mostly studied the role of localized, intensive agricultural practices in providing food to inhabitants. The aim of this review is to raise awareness and stress the knowledge gap on the importance of urban provisioning ES, particularly when implementing an edible green infrastructure (EGI) approach as it can offer improved resilience and quality of life in cities. We compiled and systematically analyzed studies on urban ES and ED related to a number of EGI typologies. Our systematic review of the relevant literature via an EGI framework, identified more than 80 peer-reviewed publications that focused on ES and food production in urban areas. An EGI approach can contribute socially, economically, and environmentally to urban sustainability and food security. However, such benefits must be weighed against ED trade-offs, including: potential health risks caused by human exposure to heavy metals and organic chemical contaminants often present in urban surroundings. We conclude with recommendations and guidelines for incorporating EGI into urban planning and design, and discuss novel areas for future research.

Abstract Purpose The reduction of the greenhouse gas nitrous oxide (N2O) to dinitrogen (N2) via denitrification and N2O source partitioning between nitrification and denitrification remain major uncertainties in sugarcane systems. We therefore investigated magnitude and product stoichiometry of denitrification and production pathways of N2O from a tropical sugarcane soil in response to increasing soil nitrate (NO3−) availability. Methods Microcosms were established using a tropical sugarcane soil (Qld, Australia) and emissions of N2O and N2 were measured following fertilisation with 15NO3−–N equivalent to 25, 50 and 100 μg N g−1 soil, simulating soil NO3− contents previously observed in situ, and mimicking flood irrigation by wetting the soil close to saturation. Results Cumulative N2O emissions increased exponentially with NO3− availability, while cumulative N2 emissions followed an exponential increase to maximum. Average daily N2 emissions exceeded 5 µg N2–N g soil−1 and accounted for > 99% of denitrification. The response of N2O suggests preferential NO3− reduction with increasing NO3− availability, increasing N2O even when NO3− levels had only a diminishing effect on the overall denitrification rate. The fraction of N2O emitted from denitrification increased with NO3− availability, and was a function of soil water, NO3− and heterotrophic soil respiration. Conclusions Our findings show the exponential increase of N2O driven by excess NO3−, even though the complete reduction to N2 dominated denitrification. The low N2O/(N2O + N2) product ratio questions the use of N2O as proxy for overall denitrification rates, highlighting the need for in-situ N2 measurements to account for denitrification losses from sugarcane systems.

Climate change and land-cover change will have major impacts on biodiversity persistence worldwide. These two stressors are likely to interact, but how climate change will mediate the effects of land-cover change remains poorly understood. Here we use an empirically-derived model of the interaction between habitat loss and climate to predict the implications of this for biodiversity loss and conservation priorities at a global scale. Risk analysis was used to estimate the risk of biodiversity loss due to alternative future land-cover change scenarios and to quantify how climate change mediates this risk. We demonstrate that the interaction of climate change with land-cover change could increase the impact of land-cover change on birds and mammals by up to 43% and 24% respectively and alter the spatial distribution of threats. Additionally, we show that the ranking of global biodiversity hotspots by threat depends critically on the interaction between climate change and habitat loss. Our study suggests that the investment of conservation resources will likely change once the interaction between climate change and land-cover change is taken into account. We argue that global conservation efforts must take this into account if we are to develop cost-effective conservation policies and strategies under global change.

Abstract Conservation agriculture (CA) changes soil properties and processes compared to conventional agriculture. These changes can, in turn, affect the delivery of ecosystem services, including climate regulation through carbon sequestration and greenhouse gas emissions, and regulation and provision of water through soil physical, chemical and biological properties. Conservation agriculture can also affect the underlying biodiversity that supports many ecosystem services. In this overview, we summarize the current status of the science, the gaps in understanding, and highlight some research priorities for ecosystem services in conservational agriculture. The review is based on global literature but also addresses the potential and limitations of conservation agriculture for low productivity, smallholder farming systems, particularly in Sub Saharan Africa and South Asia. There is clear evidence that topsoil organic matter increases with conservation agriculture and with it other soil properties and processes that reduce erosion and runoff and increase water quality. The impacts on other ecosystem services are less clear. Only about half the 100+ studies comparing soil carbon sequestration with no-till and conventional tillage indicated increased sequestration with no till; this is despite continued claims that conservation agriculture sequesters soil carbon. The same can be said for other ecosystem services. Some studies report higher greenhouse gas emissions (nitrous oxide and methane) with conservation agriculture compared to conventional, while others find lower emissions. Soil moisture retention can be higher with conservation agriculture, resulting in higher and more stable yields during dry seasons but the amounts of residues and soil organic matter levels required to attain higher soil moisture content is not known. Biodiversity is higher in CA compared to conventional practices. In general, this higher diversity can be related to increased ecosystem services such as pest control or pollination but strong evidence of cause and effect or good estimates of magnitude of impact are few and these effects are not consistent. The delivery of ecosystem services with conservation agriculture will vary with the climate, soils and crop rotations but there is insufficient information to support a predictive understanding of where conservation agriculture results in better delivery of ecosystem services compared to conventional practices. Establishing a set of strategically located experimental sites that compare CA with conventional agriculture on a range of soil-climate types would facilitate establishing a predictive understanding of the relative controls of different factors (soil, climate, and management) on ES outcomes, and ultimately in assessing the feasibility of CA or CA practices in different sites and socioeconomic situations. The feasibility of conservation agriculture for recuperating degraded soils and increasing crop yields on low productivity, smallholder farming systems in the tropics and subtropics is discussed. It is clear that the biggest obstacle to improving soils and other ES through conservation agriculture in these situations is the lack of residues produced and the competition for alternate, higher value use of residues. This limitation, as well as others, point to a phased approach to promoting conservation agriculture in these regions and careful consideration of the feasibility of conservation agriculture based on evidence in different agroecological and socioeconomic conditions.

Biomass combustion significantly contributes to indoor and outdoor air pollution and to the adverse health effects observed in the exposed populations. Besides, the contribution to toxicity of the particles derived from combustion of different biomass sources (pellet, wood, charcoal), as well as their biological mode of action, are still poorly understood. In the present study, we investigate the toxicological properties of PM10 particles emitted indoor from a stove fueled with different biomasses. PM10 was sampled by gravimetric methods and particles were chemically analyzed for Polycyclic Aromatic Hydrocarbons (PAHs) and elemental content. Human lung A549 cells were exposed for 24 h to 1-10 μg/cm2 PM and different biological endpoints were evaluated to comparatively estimate the cytotoxic, genotoxic and pro-inflammatory effects of the different PMs. Pellet PM decreased cell viability, inducing necrosis, while charcoal and wood ones mainly induced apoptosis. Oxidative stress-related response and cytochrome P450 enzymes activation were observed after exposure to all the biomasses tested. Furthermore, after pellet exposure, DNA lesions and cell cycle arrest were also observed. The severe genotoxic and pro-necrotic effects observed after pellet exposure were likely the consequence of the high metal content. By administering the chelating agent TPEN, the genotoxic effects were indeed rescued. The higher content in PAHs measured in wood and charcoal PMs was likely the reason of the enhanced expression of metabolizing and oxidative stress-related enzymes, like CYP1B1 and HO-1, and the consequent increase in apoptotic cell death. These data suggest that combustion particles from different biomass sources may impact on lung cells according to different pathways, finally producing different toxicities. This is strictly related to the PM chemical composition, which reflects the quality of the combustion and the fuel in particular. Further studies are needed to clarify the role of particle dimension and the molecular mechanisms behind the harmful effects observed.

AbstractCoral reef ecosystems are seriously threatened by changing conditions in the ocean. Although many factors are implicated, climate change has emerged as a dominant and rapidly growing threat. Developing a long‐term strategic plan for the conservation of coral reefs is urgently needed yet is complicated by significant uncertainty associated with climate change impacts on coral reef ecosystems. We use Modern Portfolio Theory to identify coral reef locations globally that, in the absence of other impacts, are likely to have a heightened chance of surviving projected climate changes relative to other reefs. Long‐term planning that is robust to uncertainty in future conditions provides an objective and transparent framework for guiding conservation action and strategic investment. These locations constitute important opportunities for novel conservation investments to secure less vulnerable yet well‐connected coral reefs that may, in turn, help to repopulate degraded areas in the event that the climate has stabilized.

AbstractClimate change and human pressures are changing the global distribution and the extent of intermittent rivers and ephemeral streams (IRES), which comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and undergo physico‐chemical changes (preconditioning), and periods of flow resumption, when these substrates are rewetted and release pulses of dissolved nutrients and organic matter (OM). However, there are no estimates of the amounts and quality of leached substances, nor is there information on the underlying environmental constraints operating at the global scale. We experimentally simulated, under standard laboratory conditions, rewetting of leaves, riverbed sediments, and epilithic biofilms collected during the dry phase across 205 IRES from five major climate zones. We determined the amounts and qualitative characteristics of the leached nutrients and OM, and estimated their areal fluxes from riverbeds. In addition, we evaluated the variance in leachate characteristics in relation to selected environmental variables and substrate characteristics. We found that sediments, due to their large quantities within riverbeds, contribute most to the overall flux of dissolved substances during rewetting events (56%–98%), and that flux rates distinctly differ among climate zones. Dissolved organic carbon, phenolics, and nitrate contributed most to the areal fluxes. The largest amounts of leached substances were found in the continental climate zone, coinciding with the lowest potential bioavailability of the leached OM. The opposite pattern was found in the arid zone. Environmental variables expected to be modified under climate change (i.e. potential evapotranspiration, aridity, dry period duration, land use) were correlated with the amount of leached substances, with the strongest relationship found for sediments. These results show that the role of IRES should be accounted for in global biogeochemical cycles, especially because prevalence of IRES will increase due to increasing severity of drying events.