Street trees, native plantings, bioswales, and other forms of green infrastructure alleviate urban air and water pollution, diminish flooding vulnerability, support pollinators, and provide other benefits critical to human well-being. Urban planners increasingly value such urban ecosystem services (ES), and effective methods for deciding among alternative planting regimes using urban ES criteria are under active development. In this effort, integrating stakeholder values and concerns with quantitative urban ES assessments is a central challenge; although it is widely recommended, specific approaches have yet to be explored. Here, we develop, apply, and evaluate such a method in the Friendly Area Neighborhood of Eugene, Oregon by investigating the potential for increased urban ES through the conversion of public lawn to alternative planting regimes that align with expressed stakeholder priorities. We first estimated current urban ES from green space mapping and published supply rates, finding lawn cover and associated ES to be dominant. Resident and expert priorities were then revealed through surveys and Delphi analyses; top priorities included air quality, stormwater quality, native plantings, and pollinator habitat, while concerns focused on cost and safety. Unexpectedly, most residents expressed a willingness to support urban ES improvements financially. This evidence then informed the development of planting regime alternatives among which we compared achievable future urban ES delivery, revealing clear differences among those that maximized stakeholder priorities, those that maximized quantitative urban ES delivery, and their integration. The resulting contribution is a straightforward method for identifying planting regimes with a high likelihood of success in delivering desired urban ES in specific local contexts.

No abstract

<p>Cities represent a significant source of atmospheric elemental carbon (EC), a minor constituent of particulate matter (PM) but a major climate-forcing agent and air pollutant. Urban trees scavenge PM and regulate material fluxes to the ground. As such, urban trees represent potentially important sinks—not only for PM but also for EC—in urban landscapes. Here we assess the magnitude and spatiotemporal drivers of EC removal by trees in urban atmospheres. We quantified foliar EC accumulation by, as well as throughfall EC flux under, the canopy of two oak species (<em>Quercus stellata</em>: post oak; <em>Quercus virginiana</em>: live oak), which are widespread across the southern United States. Sampling was conducted from March 2017 to March 2018 across the City of Denton, a city at the northern edge of the Dallas-Forth Worth metropolitan area in Texas. Over the year-long study period, we found that post oak tree canopies accumulated two times more EC (0.53 mg EC m<sup>-2</sup> leaf d<sup>-1</sup>) than live oak trees (0.22 mg EC m<sup>-2</sup> leaf d<sup>-1</sup>), with 95% of EC depositing to leaf surfaces as opposed to leaf waxes. Throughfall EC fluxes were also greater under post oak (0.15 mg EC m<sup>-2</sup> d<sup>-1</sup>) compared to live oak (0.12 mg EC m<sup>-2</sup> d<sup>-1</sup>) canopies, but these differences between post oak and live oak were far less pronounced than for foliar EC accumulation. These results suggest that considerable amounts of dry-deposited EC are retained in post oak canopies, reducing species differences in throughfall EC fluxes. Our findings also revealed strong, albeit, contrasting seasonal patterns for foliar EC accumulation and throughfall EC fluxes. For both tree species, EC accumulation on canopy surfaces increased, whereas throughfall EC fluxes decreased from spring to fall, providing additional evidence that EC retention on canopy surfaces results in decreased EC fluxes to the ground. In summary, our findings show that urban oak trees scavenge considerable amounts of EC from the atmosphere and that the magnitude of accumulation and delivery to soil vary by species and season. This research highlights the potential for urban trees and forests to contribute to climate and air quality mitigation.</p>

No abstract

Physical scientists, social scientists, humanities scholars, and journalists have all framed Antarctica as a place of global importance—as a laboratory for scientific research, as a strategic site for geopolitical agendas, and more recently as a source of melting ice that could catastrophically inundate populations worldwide. Yet, the changing cryosphere impacts society within Antarctica as well, and this article expands the focus of Antarctic ice research to include human activities on and around the continent. It reframes Antarctica as a place with human history and local activities that are being affected by melting ice, even if the consequences are much smaller in scale than the effects of global sea level rise. Specifically focused on tourism and conservation along the west Antarctica Peninsula (wAP), this article demonstrates the impacts of changing glaciers and sea ice on the timing, location, and type of tourism as well as the ability of changing ice to mediate human experiences through conservation agendas. As future ice conditions influence Antarctic tourism and conservation, an attention to issues emerging within the wAP region offers a new perspective on climate change impacts and the management of Antarctic activities in the 21st-century Anthropocene.