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Significance Global demand for species used in traditional medicine is increasing among wealthy urban consumers. This growing trade provides livelihood opportunities for harvesters, but also risks causing resource overexploitation. A dearth of reliable data hinders assessments of whether these species are declining, and why. We investigate these issues for Himalayan caterpillar fungus—one of the world’s most expensive medicinal species—by integrating local harvesters’ knowledge of production trends with ecological modeling. We find that harvesters increasingly attribute declining production to overexploitation, while models indicate that climate warming is also contributing to this decline. Our results underscore the “double whammy” threatening highly valuable species, and demonstrate the complementarity of different knowledge systems for assessing the sustainability of the medicinal resource trade., Demand for traditional medicine ingredients is causing species declines globally. Due to this trade, Himalayan caterpillar fungus (Ophiocordyceps sinensis) has become one of the world’s most valuable biological commodities, providing a crucial source of income for hundreds of thousands of collectors. However, the resulting harvesting boom has generated widespread concern over the sustainability of its collection. We investigate whether caterpillar fungus production is decreasing—and if so, why—across its entire range. To overcome the limitations of sparse quantitative data, we use a multiple evidence base approach that makes use of complementarities between local knowledge and ecological modeling. We find that, according to collectors across four countries, caterpillar fungus production has decreased due to habitat degradation, climate change, and especially overexploitation. Our statistical models corroborate that climate change is contributing to this decline. They indicate that caterpillar fungus is more productive under colder conditions, growing in close proximity to areas likely to have permafrost. With significant warming already underway throughout much of its range, we conclude that caterpillar fungus populations have been negatively affected by a combination of overexploitation and climate change. Our results underscore that harvesting is not the sole threat to economically valuable species, and that a collapse of the caterpillar fungus system under ongoing warming and high collection pressure would have serious implications throughout the Himalayan region.

Significance Supply chains tied to multinational corporations represent over 80% of global trade and engage over one in five workers. Supply-chain management therefore has a significant impact on key social and environmental challenges. Despite this importance, there is currently no comprehensive, empirically grounded understanding of how companies address sustainability in their supply chains. We develop a global database based on a random sample of publicly listed companies with annual reports in English to provide insight into how the private sector contributes to advancing global sustainability via their supply chains. This study provides a large-scale empirical analysis of corporate sustainable-sourcing practices across multiple sectors and geographies., Global supply chains play a critical role in many of the most pressing environmental stresses and social struggles identified by the United Nations’ Sustainable Development Goals (SDGs). Responding to calls from the global community, companies are adopting a variety of voluntary practices to improve the environmental and/or social management of their suppliers’ activities. We develop a global survey of 449 publicly listed companies in the food, textile, and wood-products sectors with annual reports in English to provide insight into how the private sector contributes to advancing the SDGs via such sustainable-sourcing practices. We find that while 52% of companies use at least one sustainable-sourcing practice, these practices are limited in scope; 71% relates to only one or a few input materials and 60.5% apply to only first-tier suppliers. We also find that sustainable-sourcing practices typically address a small subset of the sustainability challenges laid out by the SDGs, primarily focusing on labor rights and compliance with national laws. Consistent with existing hypotheses, companies that face consumer and civil society pressure are associated with a significantly higher probability of adopting sustainable-sourcing practices. Our findings highlight the opportunities and limitations of corporate sustainable-sourcing practices in addressing the myriad sustainability challenges facing our world today.

Growing demand for agricultural commodities is causing the expansion of agricultural frontiers onto native vegetation worldwide. Agribusiness companies linking these frontiers to distant spaces of consumption through global commodity chains increasingly make zero-deforestation pledges. However, production and land conversion are often carried out by less-visible local and regional actors that are mobile and responsive to new agricultural expansion opportunities and legal constraints on land use. With more stringent deforestation regulations in some countries, we ask whether their movements are determined partly by differences in land-use policies, resulting in "deforestation havens." We analyze the determinants of investment decisions by agricultural companies in the Gran Chaco and Chiquitano, a region that has become the new deforestation "hot spot" in South America. We test whether companies seek out less-regulated forest areas for new agricultural investments. Based on interviews with 82 companies totaling 2.5 Mha of properties, we show that, in addition to proximity to current investments and the availability of cheap forestland, lower deforestation regulations attract investments by companies that tend to clear more forest, mostly cattle ranching operations, and that lower enforcement attracts all companies. Avoiding deforestation leakage requires harmonizing deforestation regulations across regions and commodities and promoting sustainable intensification in cattle ranching.

We thank Ronit Levine-Schnur for the interest she took in our paper and for taking the time to suggest improvements to the methods (1). Finding ways to accurately measure enforcement is an important challenge for sustainability research, and especially so for research conducted in data-poor environments such as the Gran Chaco and Chiquitano region, where government institutions themselves sometimes lack proper data on illegal deforestation and fines. Borner et al. (2) applied previous economic theorizations about optimal law enforcement to the context of illegal … [↵][1]1To whom correspondence should be addressed. Email: elambin{at}stanford.edu. [1]: #xref-corresp-1-1

Reducing tropical deforestation is an international priority, given its impacts on carbon emissions and biodiversity. We examined whether recent forest transitions—a shift from net deforestation to net reforestation—involved a geographic displacement of forest clearing across countries through trade in agricultural and forest products. In most of the seven developing countries that recently experienced a forest transition, displacement of land use abroad accompanied local reforestation. Additional global land-use change embodied in their net wood trade offset 74% of their total reforested area. Because the reforesting countries continued to export more agricultural goods than they imported, this net displacement offset 22% of their total reforested area when both agriculture and forestry sectors are included. However, this net displacement increased to 52% during the last 5 y. These countries thus have contributed to a net global reforestation and/or decrease in the pressure on forests, but this global environmental benefit has been shrinking during recent years. The net decrease in the pressure on forests does not account for differences in their ecological quality. Assessments of the impacts of international policies aimed at reducing global deforestation should integrate international trade in agricultural and forest commodities.

In some countries across the globe, tropical forest cover is increasing. The national-scale reforestation of Vietnam since 1992 is assumed to contribute to this recovery. It is achieved, however, by the displacement of forest extraction to other countries on the order of 49 (34–70) M m 3 , or ≈39% of the regrowth of Vietnam's forests from 1987 to 2006. Approximately half of wood imports to Vietnam during this period were illegal. Leakage due to policies restricting forest exploitation and displacement due to growing domestic consumption and exports contributed respectively to an estimated 58% and 42% of total displacement. Exports of wood products from Vietnam also grew rapidly, amounting to 84% of the displacement, which is a remarkable feature of the forest transition in Vietnam. Attribution of the displacement and corresponding forest extraction to Vietnam, the source countries or the final consumers is thus debatable. Sixty-one percent of the regrowth in Vietnam was, thus, not associated with displacement abroad. Policies allocating credits to countries for reducing deforestation and forest degradation should monitor illegal timber trade and take into account the policy-induced leakage of wood extraction to other countries.

Land change science has emerged as a fundamental component of global environmental change and sustainability research. This interdisciplinary field seeks to understand the dynamics of land cover and land use as a coupled human–environment system to address theory, concepts, models, and applications relevant to environmental and societal problems, including the intersection of the two. The major components and advances in land change are addressed: observation and monitoring; understanding the coupled system—causes, impacts, and consequences; modeling; and synthesis issues. The six articles of the special feature are introduced and situated within these components of study.

Declines in habitat and wildlife in semiarid African savannas are widely reported and commonly attributed to agropastoral population growth, livestock impacts, and subsistence cultivation. However, extreme annual and shorter-term variability of rainfall, primary production, vegetation, and populations of grazers make directional trends and causal chains hard to establish in these ecosystems. Here two decades of changes in land cover and wildebeest in the Serengeti-Mara region of East Africa are analyzed in terms of potential drivers (rainfall, human and livestock population growth, socio-economic trends, land tenure, agricultural policies, and markets). The natural experiment research design controls for confounding variables, and our conceptual model and statistical approach integrate natural and social sciences data. The Kenyan part of the ecosystem shows rapid land-cover change and drastic decline for a wide range of wildlife species, but these changes are absent on the Tanzanian side. Temporal climate trends, human population density and growth rates, uptake of small-holder agriculture, and livestock population trends do not differ between the Kenyan and Tanzanian parts of the ecosystem and cannot account for observed changes. Differences in private versus state/communal land tenure, agricultural policy, and market conditions suggest, and spatial correlations confirm, that the major changes in land cover and dominant grazer species numbers are driven primarily by private landowners responding to market opportunities for mechanized agriculture, less by agropastoral population growth, cattle numbers, or small-holder land use.