Suchergebnisse

We are currently living in the most explosive era of infrastructure expansion in human history. By 2050, it is projected that there will be an additional 25 million kilometers of paved roads on Earth—enough to encircle the planet more than 600 times. Around nine‐tenths of these roads will be built in developing nations and tropical regions, which sustain many of the planet's most biologically diverse and environmentally importantecosystems. Unfortunately, the contemporary avalanche of new infrastructure is having severe impacts on many ecosystems and species. However, not all infrastructure is 'bad' for the environment. In appropriate contexts, new infrastructure can yield sizeable social and economic benefits with only limited environmental costs. For instance, road improvements in already‐settled areas can facilitate increases in agricultural production and improve rural livelihoods, by giving farmers better access to urban markets, fertilizers, and new agricultural technologies. Our team at James Cook University, Cairns are working in conjunction with researchers from the University of Papua New Guinea, the Papua New Guinean government and non‐government organizations to devise and implement spatial land‐use planning tools that will minimize the environmental costs and maximize the socioeconomic benefits of road expansion.

Ghana's protected forest reserves have suffered average annual deforestation rates of 0.7%, 0.5%, 0.4%, and 0.6% for the periods 1990–2000, 2000–2005, 2005–2010 and 2010–2015, respectively. The Ashanti region has recorded the second highest deforestation rates. Despite the government's efforts to maintain and protect Ghana's forest reserves, deforestation continues. We observed deforestation patterns in the Ashanti region of Ghana from 1986 to 2015 using Landsat imagery to identify the main causes of deforestation. We obtained and processed two adjacent Landsat images from the United States Geological Survey's (USGS) National Centre for Earth Resources Observation and Science at 30 m spatial resolution for 1986, 2002, and 2015. We then supported the results with findings from 291 farm household surveys in communities fringing the forest reserves. By 2015, dense forest covered 53.3% of the land area of the forest reserves, and the remaining area had been disturbed. Expansion of annual crop farms and tree crops caused 78% of the forest loss within the 29-year period. Afforestation projects are ongoing some of which employ the participation of farmers, yet agricultural expansion exerts more pressure on the remaining dense forest. Agricultural intensification on existing farmlands may reduce farm expansion into the remaining forest areas. Strengthening and enforcing forest protection laws could minimise the extent of agricultural encroachment into forests. Mixed tree-crop systems could reduce the effects of arable farming on deforestation, limit the clearance of trees from farmlands, enhance the provision of ecosystem services, and improve the soil's fertility and moisture content. A forest transition may be underway leading to more trees in agricultural systems and better protection of residual natural forests.

The temporal trajectory of ecosystem services (ES) is often driven by changes in land use and management caused by human activities. Land intensification has been a major reason for changes in land use and management in the last decades, resulting in increases in agricultural yields and decreases in biodiversity and most ES. Previous research and models have dealt with how biodiversity declines with land intensification but knowledge is scarce on the impacts of land intensification on ES. In this paper, we explore how changes in land-use intensity influences the production of bundles of ES, using mountain landscapes as examples. We review case studies of ES dynamics in mountain landscapes and combined concepts from existing frameworks to develop a simple model of the delivery of bundles of ES along a gradient of land-use intensity. We classify the selected case studies into three groups of mountain landscape dynamics, depending on the main land-use changes: the two first groups are characterized by an increase in land-use intensity with changes towards either croplands or forest plantations respectively. The third group includes cases of decreasing land-use intensity, in which landscapes can be abandoned, rewilded or transformed from productive to multifunctional landscapes. We propose a simple model linking land-use intensity in ecosystems dominated by trees or grass to the provision of eight groups of ES: three provisioning services (food, timber and energy wood, other products), two regulation services (soil conservation and water regulation, carbon sequestration) and two cultural services (spiritual values, recreation, heritage). The analysis of case studies in terms of land-use intensity helps identifying broad groups of mountain landscape trajectories with common features of ES dynamics and highlighting common trade-offs between ES.

Road development in tropical forest landscapes is contentious. Local preferences are often subordinated to global economic and environmental concerns. Opportunities to seek solutions based on local context are rare. We examined local perspectives on road development within Cambodia's Keo Seima Wildlife Sanctuary to explore opportunities for optimizing conservation and development outcomes. We conducted household surveys to document the perceived benefits and risks of road development. We found that in the sanctuary, road rehabilitation may accelerate transitions to intensified agriculture and diversified, off-farm incomes. All households prefer good roads and poorer households prioritize road development over other village infrastructure. Households perceive the most prominent benefit of roads to be access to hospital. Local government authorities are responsible for controlling land use and conversion within village boundaries and are therefore highly influential in determining the social and environmental outcomes of roads. Strategies to mitigate environmental risks of roads without constraining development benefits must focus on improving local capacity for decision-making and transparency. Local institutions in tropical forest landscapes must have greater control over development benefits if they are to reinvest assets to achieve conservation success.