It is likely that half of the urban areas that will exist in 2050 have not yet been designed and built. This provides tremendous opportunities for enhancing urban sustainability, and using “nature in cities” is critical to more resilient solutions to urban challenges. Terms for “urban nature” include Green Infrastructure (GI), Green-Blue Infrastructure (GBI), Urban Green Space (UGS), and Nature-Based Solutions (NBS). These terms, and the concepts they represent, are incomplete because they tend to reduce the importance of non-terrestrial ecological features in cities. We argue that the concept of Urban Ecological Infrastructure (UEI), which came from a 2013 forum held in Beijing and from several subsequent 2017 publications, is a more inclusive alternative. In this paper we refine the 2013 definition of UEI and link the concept more directly to urban ecosystem services. In our refined definition, UEI comprises all parts of a city that support ecological structures and functions, as well as the ecosystem services provided by UEI that directly affect human outcomes and wellbeing. UEI often includes aspects of the built environment, and we discuss examples of this “hybrid infrastructure”. We distinguish terrestrial, aquatic, and wetland UEI because each type provides different ecosystem services. We present several examples of both “accidental” UEI and UEI that was explicitly designed and managed, with an emphasis on wetland UEI because these ecotonal ecosystems are uniquely both terrestrial and aquatic. We show how both accidental and planned UEI produces unexpected ecosystem services, which justifies recognizing and maintaining both purposeful and serendipitous types of UEI in cities. Finally, we posit that by incorporating both “ecological” and “infrastructure”, UEI also helps to bridge urban scientists and urban practitioners in a more transdisciplinary partnership to build more resilient and sustainable cities.

Mitigation of greenhouse gas (GHG) emissions and adaptation to climate risk are two essential ingredients of climate change policy. Both are needed and co-benefits may exist. Yet, mitigation and adaptation are not usually pursued together. Part of remedying this shortcoming is understanding the relationship between GHG emissions and climate vulnerability reduction and recognizing when and where they trend together. Here, we compare changes in fossil fuel CO 2 emissions per capita and in climate vulnerability scores over the past two decades in 179 countries. We use climate vulnerability scores from the well-established ND-GAIN Country Index, a composite metric constructed from thirty-six indicators covering three components of vulnerability (exposure, sensitivity and adaptive capacity). We find that 69% of the countries decreased climate vulnerability, while increasing their per capita fossil fuel CO 2 emissions. These countries are successfully reducing climate vulnerability but are increasing their GHG emissions and thus failing in mitigation efforts. In contrast, 23% of the countries have been successful in simultaneously reducing per capita CO 2 emissions and climate vulnerability. Furthermore, in highly vulnerable countries, increasing CO 2 emissions are not correlated with decreasing climate vulnerability. These findings underscore that climate vulnerability reduction may be due only partly to economic development. This finding also changes our prevailing view that increases in CO 2 emissions are associated with vulnerability reduction. Finally, examining mitigation and climate-vulnerability reduction by sector, we show that a majority of countries are able to reduce vulnerability in ecosystem services. Those countries and sectors with positive trends provide examples for others to follow, as solutions at the mitigation-climate vulnerability reduction interface are essential for sustainable economic development.

Migratory species are an important component of biodiversity and provide essential ecosystem services for humans, but many are threatened and endangered. Numerous studies have been conducted on the biology of migratory species, and there is an increased recognition of the major role of human dimensions in conserving migratory species. However, there is a lack of systematic integration of socioeconomic and environmental factors. Because human activities affect migratory species in multiple places, integrating socioeconomic and environmental factors across space is essential, but challenging. The holistic framework of telecoupling (socioeconomic and environmental interactions over distances) has the potential to help meet this challenge because it enables researchers to integrate human and natural interactions across multiple distant places. The use of the telecoupling framework may also lead to new conservation strategies and actions. To demonstrate its potential, we apply the framework to Kirtland’s warblers ( Setophaga kirtlandii ), a conservation-reliant migratory songbird. Results show accomplishments from long-term research and recovery efforts on the warbler in the context of the telecoupling framework. The results also show 24 research gaps even though the species has been relatively well-studied compared to many other species. An important gap is a lack of systematic studies on feedbacks among breeding, wintering,and stopover sites, as well as other “spillover” systems that may affect and be affected by migration (e.g., via tourism, land use, or climate change). The framework integrated scattered information and provided useful insights about new research topics and flow-centered management approaches that encapsulate the full annual cycle of migration. We also illustrate the similarities and differences between Kirtland’s warblers and several other migratory species, indicating the applicability of the telecoupling framework to understanding and managing common complexities associated with migratory species in a globalizing world.

Humans rely on marine ecosystems for a variety of services but often impact these ecosystems directly or indirectly limiting their capacity to provide such services. One growing impact is the emergence of marine disease. We present results from a unique case study examining how oysters, a dominant organism in many coastal bays and estuaries that is often harvested for food, have responded to pathogens influenced by human activities, namely the introduction of novel pathogens. Climate change has enabled a northward spread and establishment of Dermo disease in oysters along the eastern seaboard of North America and human activities inadvertently introduced MSX disease along this same coast. Oysters in Delaware Bay have responded differently to each pathogen, and uniquely to MSX disease by developing a highly resistant baywide population not documented in any other bay. Offspring were produced using parents collected from low or high disease (MSX and Dermo) regions of Delaware Bay and exposed in a common garden experiment along with a naïve population from Maine. Results indicated widespread resistance to MSX disease, but not to Dermo disease, across Delaware Bay. One striking result was the demonstration of resilience in the population through its capacity to spread, presumably through larval transport, resistance to MSX disease into portions of the population that have experienced little to no MSX disease pressure themselves. Related studies indicated that larval transport mechanisms allowed widespread dispersal such that the entire metapopulation could acquire a high level of resistance over time if disease resistance is sufficiently heritable. The findings have implications for restoration, management and recovery of diseased populations. Namely, that if left to their own devices, natural selection may find a solution that enables populations to recover from introduced pathogens.

Despite projections of biodiversity loss and proposed adaptations to climate change, few data exist on the feasibility and effectiveness of adaptation strategies in minimizing biodiversity loss. Given the urgent need for action, scientific experts can fill critical information gaps by providing rapid and discerning risk assessment. A survey of 2,329 biodiversity experts projects, on average, that 9.5% of species will become extinct due to climate change within the next 100 years. This average projection is low relative to previously published values but substantial in absolute terms, because it amounts to a loss of hundreds of thousands of species over the next century. The average projection increases to 21% when experts are asked to estimate the percentage of species that will become extinct within the next 100 years due to climate change in combination with other causes. More than three-quarters of respondents reported being uncertain about their extinction estimates. A majority of experts preferred protected areas or corridors to reduce extinction risk but identified ex situ conservation and no intervention as the most feasible strategies. Experts also suggest that managed relocation of species, a particular adaptation strategy, is justifiable and effective in some situations but not others. Justifiable circumstances include the prevention of species extinction and overcoming human-made barriers to dispersal, and while experts are divided on the potential effectiveness of managed relocation for most taxonomic groups, higher percentages predict it effective for woody plants, terrestrial insects, and mammals. Most experts are open to the potential benefits of managed relocation but are concerned about unintended harmful consequences, particularly putting non-target species at risk of extinction. On balance, published biodiversity scientists feel that managed relocation, despite controversy about it, can be part of the conservation adaptation portfolio.