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Changes in temperature and moisture resulting from climate change are likely to strongly modify the ecosystem carbon sequestration capacity in high-latitude areas, both through vegetation shifts and via direct warming effects on photosynthesis and decomposition. This paper offers a synthesis of research addressing the potential impacts of climate warming on soil processes and carbon fluxes at the forest–tundra ecotone in Scandinavia. Our results demonstrated higher rates of organic matter decomposition in mountain birch forest than in tundra heath soils, with markedly shallower organic matter horizons in the forest. Field and laboratory experiments suggest that increased temperatures are likely to increase CO2 efflux from both tundra and forest soil providing moisture availability does not become limiting for the decomposition process. Furthermore, colonization of tundra heath by mountain birch forest would increase rates of decomposition, and thus CO2 emissions, from the tundra heath soils, which currently store substantial amounts of potentially labile carbon. Mesic soils underlying both forest and tundra heath are currently weak sinks of atmospheric methane, but the strength of this sink could be increased with climate warming and/or drying.
Introduced reindeer, Rangifer tarandus, overexploited lichen-rich plant communities on St. Matthew Island in the Bering Sea. A die-off of the reindeer followed, exacerbated by extreme weather in 1964, resulting in extirpation of the reindeer. A similar pattern of removal of lichens as major components of plant communities has occurred following introductions of reindeer to other islands at high latitudes. By 1985, two decades following die-off of the reindeer, total lichen biomass was only 6% of that in similar plant communities on adjacent Hall Island, not reached by the reindeer. By 2005, 41 y after the reindeer die-off, lichen regrowth on St. Matthew was only 12% of lichen biomass in the Hall Island communities. A warmer, drier climate and decreased fog in recent decades contributed to deterioration of conditions favoring lichen growth on St. Matthew Island.
This paper provides an overview of the evolution of pollution problems in the Northeast Atlantic and associated responses and considers the effectiveness of these measures on environmental contamination. It identifies shortcomings in past practices and shows how marine environmental pollution may be perpetuated if new products and processes release novel contaminants or “emerging substances” without adequate management on a precautionary basis. The study concludes that it is necessary to develop innovative techniques capable of making reasonable quantitative estimates of not only environmental pathways, loads, and concentrations but also the socioeconomic drivers and “upstream” control measures (control, reduction, or elimination of emissions) so that a clear understanding of the causes and effects of our actions can be obtained. The development of a European Observatory for Emerging Substances to coordinate concerns, observations, and practices is suggested as a proactive approach for anticipating emerging problems.
Aquaculture is seen as an alternative to meeting the widening gap in global rising demand and decreasing supply for aquatic food products. Asia, the epicenter of the global aquaculture industry, accounts for over 90% of the global aquaculture production quantity and about 80% of the value. Asian aquaculture, as with global aquaculture, is dependent to a significant extent on alien species, as is the case for all the major food crops and husbanded terrestrial animals. However, voluntary and or accidental introduction of exotic aquatic species (alien species) is known to negatively impact local biodiversity. In this relatively young food production industry, mitigating the dependence on alien species, and thereby minimizing potential negative impacts on biodiversity, is an imperative for a sustainable future. In this context an attempt is made in this synthesis to understand such phenomena, especially with reference to Asian inland finfish, the mainstay of global aquaculture production. It is pointed out that there is potential for aquaculture, which is becoming an increasingly important food production process, not to follow the past path of terrestrial food crops and husbanded animals in regard to their negative influences on biodiversity.
Development of effective indicators is indispensable for countries and societies to monitor effects of their actions on biodiversity, as is recognized in decision VI/26 of the Convention on Biological Diversity. Good indicators would ideally be scalable, at least for the different scales that characterize biodiversity patterns and process. Existing indicators are mostly global in scope, and often based on secondary information, such as classifications of endangered species, rather than on primary data. We propose a complementary approach, based on the increased availability of raw data about occurrences of species, cutting-edge modeling techniques for estimating distributional areas, and land-use information based on remotely sensed data to allow estimation of rates of range loss for species affected by land-use conversion. This method can be implemented by developing countries, given increasing availability of data and the open and well-documented nature of the techniques required.
This paper describes the process of urbanization and land use change in the urban ecosystems of the National Capital Region (NCR) of Delhi, India. Two types of land use change are considered—from natural to urban and from agricultural to urban. Both types are explained in terms of economic variables known to be drivers of change. A panel data method was used, and economic variables were combined with GIS-based information on land use change during 1986–2004 for 11 administrative units of the NCR. The results suggest that investment in the construction sector plays a major role in converting the land from natural to urban areas, while differences in land productivity seems to be the major driver for change from agricultural to urban uses.
The Tapajos River Basin in the Brazilian Amazon is the location of one of the largest concentrations of artisanal and small-scale miners in the world. Today, 40 000 miners produce 8 t of gold annum−1 and at least double this amount of mercury is released into the environment. This region was selected under the Global Mercury Project, a United Nations program that aims to reduce the environmental and health impacts caused by mercury through the application of cleaner technologies and increased awareness. A group of educators provided support to miners, training 4200 people in 141 mining locations. The effectiveness of this training was evaluated based on 20 performance indicators. After 120 days of training, an absolute improvement of approximately 29% had been achieved. As a result of this training, it is estimated that annual mercury emissions in Tapajos have been reduced by 1762 kg or around 10% of the total mercury released in the region.
In the Langcang (Upper-Mekong) watershed, degraded watershed ecosystems in upland areas threaten cultivation practices, water resources, and dam development downstream. Assessment of ecosystem services and the factors that threaten them is an important first step to support watershed management. This, however, requires detailed information that is often missing in mountainous regions. To overcome this, in this paper, we adopt a decision tree approach to assess protection, biodiversity, and production services in two mountainous watersheds (Fengqing and Xiaojie) of the Lancang River Basin. Decision tree rules were built on the basis of field surveys, available references, ecosystem maps derived from remote sensing, expert knowledge, basic topographic information, and community interviews. Decision tree results showed that forest cover and agro-forestry practices contribute greatly to improved ecosystem functioning in the Fengqing Catchment compared to the Xiaojie Catchment. The results were consistent with field observations. The decision tree method proved to be a suitable and flexible tool for the rapid assessment of watershed ecosystem services, for highlighting those areas that need more in-depth research, and for guiding watershed and ecosystem management.
China is the world's most populous country and has one of the largest territories. As such, Chinese attitudes and behavior with regard to environmental issues are key factors in protecting the world's natural resources and environment. In this study, we surveyed a random sample of 5000 citizens from six Chinese provinces (Beijing, Shanghai, Hubei, Hunan, Henan, and Shaanxi) to understand their environmental attitudes, contrasts between the attitudes of citizens in different demographic groups, and their willingness to invest in environmental conservation. The results indicated that policymakers and the public increasingly recognize the key role that environmental restoration plays in protecting the overall health of the environment. In total, 91% of the interviewees believed that the environment had deteriorated severely during the past decade, compared with 44% in a 1999 survey. In addition, 78% of the interviewees supported their government's investment of more than 300 billion RMB (∼10% of total government revenues in 2004) in the “Grain for Green Project,” which discouraged unsustainable land use by compensating farmers and herders for abandoning farming and grazing on marginal land. There was a strong correlation between environmental attitudes and net income and education levels, and other differences were based on the respondents' age, gender, job, and location. Net income and education level were the key factors that affected environmental attitudes. Based on these results, we propose that successful environmental restoration projects must include both an education component and an economic development component.