Conservation

Providing food, timber, energy, housing, and other goods and services, while maintaining ecosystem functions and biodiversity that underpin their sustainable supply, is one of the great challenges of our time. Understanding the drivers of land-use change and how policies can alter land-use change will be critical to meeting this challenge. Here we project land-use change in the contiguous United States to 2051 under two plausible baseline trajectories of economic conditions to illustrate how differences in underlying market forces can have large impacts on land-use with cascading effects on ecosystem services and wildlife habitat. We project a large increase in croplands (28.2 million ha) under a scenario with high crop demand mirroring conditions starting in 2007, compared with a loss of cropland (11.2 million ha) mirroring conditions in the 1990s. Projected land-use changes result in increases in carbon storage, timber production, food production from increased yields, and >10% decreases in habitat for 25% of modeled species. We also analyze policy alternatives designed to encourage forest cover and natural landscapes and reduce urban expansion. Although these policy scenarios modify baseline land-use patterns, they do not reverse powerful underlying trends. Policy interventions need to be aggressive to significantly alter underlying land-use change trends and shift the trajectory of ecosystem service provision.

Freshwater ecosystems provide vital resources for humans and support high levels of biodiversity, yet are severely threatened throughout the world. The expansion of human land uses, such as urban and crop cover, typically degrades water quality and reduces freshwater biodiversity, thereby jeopardizing both biodiversity and ecosystem services. Identifying and mitigating future threats to freshwater ecosystems requires forecasting where land use changes are most likely. Our goal was to evaluate the potential consequences of future land use on freshwater ecosystems in the coterminous United States by comparing alternative scenarios of land use change (2001-2051) with current patterns of freshwater biodiversity and water quality risk. Using an econometric model, each of our land use scenarios projected greater changes in watersheds of the eastern half of the country, where freshwater ecosystems already experience higher stress from human activities. Future urban expansion emerged as a major threat in regions with high freshwater biodiversity (e.g., the Southeast) or severe water quality problems (e.g., the Midwest). Our scenarios reflecting environmentally oriented policies had some positive effects. Subsidizing afforestation for carbon sequestration reduced crop cover and increased natural vegetation in areas that are currently stressed by low water quality, while discouraging urban sprawl diminished urban expansion in areas of high biodiversity. On the other hand, we found that increases in crop commodity prices could lead to increased agricultural threats in areas of high freshwater biodiversity. Our analyses illustrate the potential for policy changes and market factors to influence future land use trends in certain regions of the country, with important consequences for freshwater ecosystems. Successful conservation of aquatic biodiversity and ecosystem services in the United States into the future will require attending to the potential threats and opportunities arising from policies and market changes affecting land use.

Humans have altered land cover for centuries, and land-cover change is a main component of global change. Land use transition trajectories, such as the forest transition theory (i.e. switch from deforestation to stable or increasing forest cover), relate long term changes in land use to gradual changes in underlying drivers, such as economic development, demographic change, and urbanization. However, because only few studies examined land change over centuries, it is not clear how land cover changes during very long time-periods which are punctuated by shifts in socio-economics and policies, such as wars. Our goal here was to examine broad land change patterns and processes, and their main driving forces in Central and Eastern Europe during distinct periods of the past 250 years. We conducted a meta-analysis of 66 publications describing 102 case study locations and quanti?ed the main forest and agricultural changes in the Carpathian region since the 18th century. These studies captured gradual changes since the peak of the Austro-Hungarian Empire up to the accession to the European Union of most of the formerly socialist countries in the study region. Agricultural land-use increased during the Austro-Hungarian Empire in 70% of the case studies, but dropped sharply during and especially after the collapse of the Socialism (over 70% of the cases). The highest rates of abandonment occurred between 1990 and 2000. The Carpathian region experienced forest transition during the Interwar period (93% of the cases), and the forest expansion trend persisted after the collapse of Socialism (70% of the cases). In terms of the drivers, institutional and economic factors were most in?uential in shaping deforestation and agricultural expansion, while socio- demographics and institutional shifts were the key drivers of land abandonment. Our study highlights the drastic effects that socio-economic and institutional changes can have on land-use and land-cover change, and the value of longitudinal studies of land change to uncover these effects.

High rates of climate and land-use changes threaten biodiversity and ecosystem function, creating a need for integrated assessments and planning at regional to global scales. We develop a new approach to measure multivariate estimates of climate and land-use change that builds on recently developed measures of climate velocity, and apply it to assess the combined speeds of climate and land use for the conterminous US from 2001 to 2051. The combined speeds of climate and land-use change are highest in a broad north-to-south swath in the central US and in parts of the intermountain west. Climate speeds are roughly an order of magnitude higher than land-use speeds in most regions, but land-use speed is particularly high in the Appalachians and north-central forests. Joint speeds are low across much of the intermountain west. Our results highlight areas expected to be most vulnerable to changes in biodiversity and ecosystem function due to the individual or combined effects of climate and land-use change. The integration of climate and land-use scenarios suggests different conservation prioritization strategies from climate velocities and species alone.

Sacred natural sites have played important social and cultural roles in many cultures around the world for centuries. More recently, scientists have shown that sacred sites act as de facto protected areas. However, the potential for sacred sites to be integrated into conservation strategies depends on the motivations of people to protect them. The objective of this study is to understand people's relationships with village-level sacred forests in northwest Yunnan, China. We conducted 201 standardized open-ended interviews of both men and women over 18 years of age from six communities in the area near the city of Shangrila. While this region of Yunnan is undergoing dramatic socio-economic changes that can contribute to changes in cultural values, we find no evidence that people's appreciation for sacred forests is declining. Our results show that the forests hold primarily religious meaning for people, people visit the forests regularly, and, while younger people know less about the forests, they do not differ in terms of use and appreciation, indicating that the value of the areas is not decreasing. Because people primarily view these sacred forests as religious sites and do not directly associate them with ecological value, we suggest that direct integration of these areas into conservation strategies may not be appropriate.