Gaps and opportunities for the World Heritage Convention to contribute to global wilderness conservation

Wilderness areas are ecologically intact landscapes predominantly free of human uses, especially industrial‐scale activities that result in substantial biophysical disturbance. This definition does not exclude land and resource use by local communities who depend on such areas for subsistence and bio‐cultural connections. Wilderness areas are important for biodiversity conservation and sustain key ecological processes and ecosystem services that underpin planetary life‐support systems. Despite these widely recognized benefits and values of wilderness, they are insufficiently protected and are consequently being rapidly eroded. There are increasing calls for multilateral environmental agreements to make a greater and more systematic contribution to wilderness conservation before it is too late. We created a global map of remaining terrestrial wilderness following the established last‐of‐the‐wild method, which identifies the 10% of areas with the lowest human pressure within each of Earth's 62 biogeographic realms and identifies the 10 largest contiguous areas and all contiguous areas >10,000 km². We used our map to assess wilderness coverage by the World Heritage Convention and to identify gaps in coverage. We then identified large nationally designated protected areas with good wilderness coverage within these gaps. One‐quarter of natural and mixed (i.e., sites of both natural and cultural value) World Heritage Sites (WHS) contained wilderness (total of 545,307 km²), which is approximately 1.8% of the world's wilderness extent. Many WHS had excellent wilderness coverage, for example, the Okavango Delta in Botswana (11,914 km²) and the Central Suriname Nature Reserve (16,029 km²). However, 22 (35%) of the world's terrestrial biorealms had no wilderness representation within WHS. We identified 840 protected areas of >500 km² that were predominantly wilderness (>50% of their area) and represented 18 of the 22 missing biorealms. These areas offer a starting point for assessing the potential for the designation of new WHSs that could help increase wilderness representation on the World Heritage list. We urge the World Heritage Convention to ensure that the ecological integrity and outstanding universal value of existing WHS with wilderness values are preserved.     

Guiding principles for rewilding

There has been much recent interest in the concept of rewilding as a tool for nature conservation, but also confusion over the idea, which has limited its utility. We developed a unifying definition and 10 guiding principles for rewilding through a survey of 59 rewilding experts, a summary of key organizations’ rewilding visions, and workshops involving over 100 participants from around the world. The guiding principles convey that rewilding exits on a continuum of scale, connectivity, and level of human influence and aims to restore ecosystem structure and functions to achieve a self-sustaining autonomous nature. These principles clarify the concept of rewilding and improve its effectiveness as a tool to achieve global conservation targets, including those of the UN Decade on Ecosystem Restoration and post-2020 Global Biodiversity Framework. Finally, we suggest differences in rewilding perspectives lie largely in the extent to which it is seen as achievable and in specific interventions. An understanding of the context of rewilding projects is the key to success, and careful site-specific interpretations will help achieve the aims of rewilding.     

Elemental carbon in urban soils and road dusts in Xi'an,China and its implication for air pollution

Increasing evidence confirms that elemental carbon (EC) is not only a light-absorbing constituent that warms the atmosphere but also a significant environmental pollutant. Investigations were conducted to identify carbonaceous pollution signatures in road dusts and urban soils and to evaluate potential sources in Xi'an. Average concentrations of EC, char-EC, and soot-EC in soils were 0.90, 0.51, and 0.39 mg g^?1, respectively, a little higher than or comparable to prior studies on the Loess Plateau. Vertical profiles in soils revealed soot-EC concentrations from pre-industrialized samples close to ～0.20 mg g^?1, while EC and char-EC varied widely, with no distinct pattern. Enrichment factor analysis indicated that EC, char-EC, and soot-EC in road dusts were all elevated by an order of magnitude. The spatial distribution of total EC, char-EC, and soot-EC in road dusts revealed close correspondence with human activities such as coal combustion and vehicle emissions. The average char-EC/soot-EC ratio was 1.66 for road dusts, suggesting that the main sources of carbonaceous particles are local coal combustion and vehicle emissions. The study demonstrated that EC, char-EC, and soot-EC levels in road dusts are effective indicators of anthropogenic pollution.     

PM2.5 source apportionment: reconciling receptor models for U.S. nonurban and urban long-term networks

Chemical mass balance (CMB) and trajectory receptor models were applied to speciated particulate matter with aerodynamic diameter < or =2.5 microm (PM2.5) measurements from Speciation Trends Network (STN; part of the Chemical Speciation Network [CSN]) and Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring network across the state of Minnesota as part of the Minnesota PM2.5 Source Apportionment Study (MPSAS). CMB equations were solved by the Unmix, positive matrix factorization (PMF), and effective variance (EV) methods, giving collective source contribution and uncertainty estimates. Geological source profiles developed from local dust materials were either incorporated into the EV-CMB model or used to verify factors derived from Unmix and PMF. Common sources include soil dust, calcium (Ca)-rich dust, diesel and gasoline vehicle exhausts, biomass burning, secondary sulfate, and secondary nitrate. Secondary sulfate and nitrate aerosols dominate PM2.5 mass (50-69%). Mobile sources outweigh area sources at urban sites, and vice versa at rural sites due to traffic emissions. Gasoline and diesel contributions can be separated using data from the STN, despite significant uncertainties. Major differences between MPSAS and earlier studies on similar environments appear to be the type and magnitude of stationary sources, but these sources are generally minor (<7%) in this and other studies. Ensemble back-trajectory analysis shows that the lower Midwestern states are the predominant source region for secondary ammoniated sulfate in Minnesota. It also suggests substantial contributions of biomass burning and soil dust from out-of-state on occasions, although a quantitative separation of local and regional contributions was not achieved in the current study. Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of the Air & Waste Management Association for a summary of input data, Unmix and PMF factor profiles, and additional maps.     

Source apportionment: findings from the U.S. Supersites Program

Receptor models are used to identify and quantify source contributions to particulate matter and volatile organic compounds based on measurements of many chemical components at receptor sites. These components are selected based on their consistent appearance in some source types and their absence in others. UNMIX, positive matrix factorization (PMF), and effective variance are different solutions to the chemical mass balance (CMB) receptor model equations and are implemented on available software. In their more general form, the CMB equations allow spatial, temporal, transport, and particle size profiles to be combined with chemical source profiles for improved source resolution. Although UNMIX and PMF do not use source profiles explicitly as input data, they still require measured profiles to justify their derived source factors. The U.S. Supersites Program provided advanced datasets to apply these CMB solutions in different urban areas. Still lacking are better characterization of source emissions, new methods to estimate profile changes between source and receptor, and systematic sensitivity tests of deviations from receptor model assumptions.     

Consuming water smartly: the significance of sociocultural differences to water-saving initiatives

This article explores how strategies to encourage households to consume less water, through education and the installation of smart meters, play out in actual social worlds where the texture and complexity of households, and the individuals within them, have a tendency to be simplified to average or statistical norms. Building on research and critical analysis from earlier studies, particularly in Australia, this research set out to explore Thames Water’s smarter home initiative deploying three frames – affect, habit, and the meaning of home – for thinking through the different responses of householders to the intervention. The study revealed that differences in response to the smarter home visit were articulated across income, education, gender, age, and ethnicity – not as homogenous or fixed categories, but rather as categories which emerged through the smart metering intervention. The research concluded that demand management interventions such as the smarter home visits, conceived as a relatively simple technology-driven behavioural change strategy, are more complex and nuanced in their reception and effects, especially on the user–provider relationship, in the constitution of social differences, and in the definitions of public and private spaces and practices. Acceptance or resistance of these programmes is not knowable in advance of their dissemination. For such interventions to be successful, water companies thus need to recognise the differentiated social, cultural, and economic environments in which their strategies are enacted. A failure to do so can only limit their stated objectives of reducing household water consumption.     

Cost-Effective Enforcement Of Environmental Standards

The body of information presented in this paper is directed to those individuals concerned with cost-effective enforcement of environmental standards. Its aim is twofold. One is to determine some of the differing impacts upon firm behavior of legal enforcement, of economic incentive enforcement, and of mixed legal-economic enforcement. A second objective is to initiate identification of enforcement systems which are most likely to minimize resource costs to firms and enforcement agencies of meeting environmental standards. A computerized model is used to simulate enforcement of the new source particu-late matter discharge standard for coal-fired power plants. Under current legal enforcement it is found that most plants will violate the standard, that small plants will control to higher removal levels than large plants and that firms will install relatively costly pollution control technology. Three enforcement alternatives are considered for overcoming these shortcomings: more stringent legal enforcement, economic incentive enforcement using effluent taxes, and a mixed system which uses device certification tests and effluent taxes. It is found that each of the alternatives can lead to the standard being met and tc more-or-less equal sharing in control burden across plant size. But it is only the two systems which use effluent taxes that give incentive for choosing least costly control technology. It is concluded that the two enforcement systems which use effluent taxes probably would encourage adoption of least cost control technology. This is likely to be a desirable outcome since it may lead to minimum resource costs to power plants and pollution control agencies of meeting fty ash standards. The general applicability of this conclusion to other enforcement situations is discussed.     

Temporal Variations of PM2.5, PM10, and Gaseous Precursors during the 1995 Integrated Monitoring Study in Central California

ABSTRACT

The spatial and temporal distributions of particle mass and its chemical constituents are essential for understanding the source-receptor relationships as well as the chemical, physical, and meteorological processes that result in elevated particulate concentrations in California’s San Joaquin Valley (SJV). Fine particulate matter ₍PM_2.5), coarse particulate matter (PM₁₀), and aerosol precursor gases were sampled on a 3-hr time base at two urban (Bakersfield and Fresno) and two non-urban (Kern Wildlife Refuge and Chowchilla) core sites in the SJV during the winter of 1995–1996.

Day-to-day variations of PM_2.5 and PM₁₀ and their chemical constituents were influenced by the synoptic-scale meteorology and were coherent among the four core sites. Under non-rainy conditions, similar diurnal variations of PM_2.5 and coarse aerosol were found at the two urban sites, with concentrations peaking during the nighttime hours. Conversely, PM_2.5 and coarse aerosol peaked during the morning and afternoon hours at the two non-urban sites. Under rainy and foggy conditions, these diurnal patterns were absent or greatly suppressed.

In the urban areas, elevated concentrations of primary pollutants (e.g., organic and elemental carbons) during the late afternoon and nighttime hours reflected the impact from residential wood combustion and motor vehicle exhaust. During the daytime, these concentrations decreased as the mixed layer deepened. Increases of secondary nitrate and sulfate concentrations were found during the daylight hours as a result of photochemical reactions. At the non-urban sites, the same increases in secondary aerosol concentrations occurred during the daylight hours but with a discernable lag time. Concentrations of the primary pollutants also increased at the non-urban sites during the daytime. These observations are attributed to mixing aloft of primary aerosols and secondary precursor gases in urban areas followed by rapid transport aloft to non-urban areas coupled with photochemical conversion.