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Evidence is mounting regarding the significant extent and scope of long-term human modification of “pristine nature” in the neotropics. In Amazonia, recent studies point to the landscape imprint of human activity that has transformed the forests, savannas, soils, and waterways of the basin. In this report, we describe a massive meander cutoff in the Peruvian Amazon along the Ucayali River—the fifth-longest river in the Amazon basin—that was triggered by small-scale human actions and resulted in significant ecological and economic consequences for the region. The modern case of the Masisea cutoff—near the Amazonian port city of Pucallpa, Peru (285 000 inhabitants)—indicates that humans using simple tools can play a major role in transforming large meandering rivers and their floodplains.
The purpose of this paper is to present calculations of total costs of 13 alien invasive species (AIS) in Sweden. All species are subject to control by Swedish public authorities, and estimates for most AIS include either damage cost or actual control cost. The results indicate a total annual cost between approximately 1620 and 5080 million SEK, which correspond to SEK 175 and SEK 565 per capita in Sweden. The estimates are well within the range of similar calculations for other countries, but differ with respect to the composition of costs of different AIS. Whereas costs for the agricultural and forestry sectors dominate in most other studies, the costs of AIS in Sweden are more equally divided among different categories. The results also indicate that the highest costs are attributable to unintentionally introduced AIS and that the most reliable cost estimates are related to human and animal health.
Neoliberal agricultural frontiers, defined as export-oriented farming areas motivated more by global demand and land privatization than by government subsidies, present at least two major challenges for environmental researchers: estimating land change and understanding governance types and outcomes. Environmental governance, the “filter” between human and biophysical systems, is considered in terms of two models in light of empirical evidence from a neoliberal frontier in the Brazilian Cerrado (savanna) ecoregion. Land-change analysis indicates that agricultural land uses increased from 12% of the study region in 1986 to 44% in 2000 and 55% in 2005, with a corresponding loss of native Cerrado. A prominent farming organization formed in 1990 has participated in or led several environmental policy initiatives. Evidence of both governance models is found, and dilemmas facing environmental activists and managers, as well as the farming sector, are presented. For organizations representing large commercial farmers, compliance with environmental regulations may be seen as both a cost to be borne by the farming sector and as a means to establish environmental credentials. Suggestions are made for future longitudinal work on compliance, information, agenda-setting, and discursive strategies of nonstate actors in neoliberal frontiers.
Land degradation is a global development and environment issue that afflicts China more than most countries in terms of the extent, economic impact, and number of people affected. Up-to-date, quantitative information is needed to support policy and action for food and water security, economic development, and environmental integrity. Data for a defined, recent period enable us to distinguish the legacy of historical land degradation from what is happening now. We define land degradation as long-term decline in ecosystem function and productivity and measure it by remote sensing of the normalized difference vegetation index (NDVI), the greenness index. NDVI may be translated to net primary productivity (NPP). Deviation from the norm serves as a proxy assessment of land degradation and improvement—if other factors that may be responsible are taken into account. These other factors include climate, which may be assessed by rain-use efficiency and energy-use efficiency. Analysis of the 23-year Global Inventory Modeling and Mapping Studies (GIMMS) NDVI data reveals that, in China over the period 1981–2003, NPP increased overall, but areas of declining climate-adjusted NPP comprise 23% of the country, mainly in south China. About 35% of China's population (457 million out of 1 317 million) depend on the degrading land. Degrading areas suffered a loss of NPP of 12 kgC ha−1 y−1, amounting to almost 60 million tC not fixed from the atmosphere; loss of soil organic carbon from these areas is likely to be orders of magnitude greater. There is no correlation between land degradation and dry lands; it is more of an issue in cropland and forest: 21% of degrading land is cropland and 40% is forest, 24% of the arable and 44% of the forest, respectively. There is no simple statistical relationship between land degradation and rural population density or poverty. Most identified land degradation is in the south and east, driven by unprecedented land-use change.
Wetlands are among the most valuable ecosystems in the world and are crucial in supporting biodiversity. They also provide space for storing surface waters, where intense biological processing occurs that helps improve water quality. Human activities, particularly irrigated agriculture and urban developments instigating water diversions from rivers, have altered the hydrology of most wetlands. The Lower Murrumbidgee wetland, located in the Murrumbidgee River Catchment, is an example and is one of the significant wetlands across the Murray Darling Basin of Australia. Historic estimates show the volumes of water ranged from none in dry years to about 300 to 400 GL (1 GL = 109 L) in an average and wet year, respectively. The flows reaching the Lower Murrumbidgee wetland have been drastically reduced by at least 60% because of the upstream diversions introduced during the last century. These reductions have adversely affected the health of natural vegetation and agricultural crops in the Lower Murrumbidgee floodplain. This article presents the results of the quantification of total water consumption of various land uses in the Lower Murrumbidgee floodplain using the remote sensing–based Surface Energy Balance Algorithm for Land (SEBAL) modeling approach. The spatial analysis of actual evapotranspiration (ETa) shows that ETa rates are the highest (13–26%) for the red gum (Eucalyptus camaldulensis) forests both in summer and winter days. However, in terms of total ETa volume, lignum (Muehlenbeckia florulenta) constitutes the most significant part, which is around 14–30% of the total ETa volume for the area. Actual evapotranspiration from winter cereal cropping areas following the summer ponding is the third highest consumer of water after the river red gum and lignum. Actual evapotranspiration from the fallow land is also significant, representing 5–28% of total ETa from the region. In view of the extent of the unaccounted flows in the overall water balance of the system, there is a need to upgrade measuring and reporting infrastructure by strengthening the institutional and management arrangements to better gauge the efficiency of environmental and consumptive water use. The state-of-the-art technology of remote sensing–based SEBAL modeling proved to have potential for measuring actual water use with reliable accuracy and can be used for assessing the environmental and productive use of water from wetlands in other regions of Australia.
The dramatic population crashes of 3 species of Gyps vulture have raised concerns about the status of their lesser-known congeners. Among these is the Himalayan griffon, G. himalayensis, an iconic vulture of the Tibetan plateau. The continued existence of this scavenger has not only ecological but also cultural implications because of their unique role in the centuries-old sky burial tradition that is followed by nearly 5 million Tibetan people. A lack of baseline information of the Himalayan griffon limits our ability to take conservation measures. The presented data, which were collected during 1996 and 2004 to 2007, indicate that this species is still widespread throughout the plateau and has not experienced a major population decline, likely as a result of protection by Tibetan Buddhism and limited disturbances from human activities largely due to the remoteness of the plateau. Both site and road counts showed that open meadow habitats had the highest griffon abundance, followed by alpine shrub and forest habitats. Estimates based on road transect counts showed that 229 339 Himalayan griffons (± 40 447) occupy the 2.5 million km2 Tibetan plateau. In contrast, the maximum carrying capacity of the plateau, on the basis of the total biomass of potential food resources, is 507 996 griffons, with meadow habitats accounting for about 76% of the total population. Griffons depend largely on livestock carcasses for food and forage in groups averaging 5.5 (range 1–100) individuals. Domestic yaks provide about 64% of the griffons' diet, while wild ungulates and human corpses provide 1% and 2%, respectively. Compared with its lowland congeners, this, the only high-elevation Gyps species, had both low population density and small group size, a likely response to the harsh environmental conditions. Although griffon abundance appears relatively stable in their fairly pristine environment, precautionary measures, including investigation of threats, monitoring of population dynamics, and establishment of modern conservation consciousness among Tibetan Buddhists, should be carried out to ensure that this abundance continues.