• Road construction in forests leads to increased deforestation not only by farmers claiming land but also by logging companies.

However, there is still inadequate knowledge on such key issues as these:

  • How to develop land management institutions that both respond to local needs and mitigate global environmental change.

  • How to aggregate in-depth studies of land cover and land use to provide global projections of use in large-scale modeling and international management of global change.

  • The role of population mobility in land use change.

  • How to best use the expanding range of satellite data in land use/land cover change research.

Human Impacts on Coastal and Marine Ecosystems

Global change research encompasses the study of changes in coastal and marine ecosystems insofar as they are affected by physical and socioeconomic processes that are global in scale and effect. Social and applied scientists have investigated the importance of coastal and marine ecosystems for many communities, regions, and nations. They have also addressed the ways in which resource use and pollution have altered the condition and biodiversity of coastal ecosystems in many regions of the world, including the destruction of protective and productive mangrove ecosystems, the degradation of coastal lagoons and estuaries and species that live or reproduce in them, and the minor contamination of even the deep and remote oceans.

Steady increases in demand, technological capacity, and effort have led to a long-term trend of increasing fish catches, which is believed to have leveled off during the 1990s, indicating limits to sustainable harvests.39 Heavy fish mortality means that environmental fluctuations as well as other human impacts, such as pollution and degradation of habitat, make fisheries even more vulnerable.40 Social scientists and others have documented the roles of technological change, population growth, institutional structures, and social attitudes in driving demand for fish and other marine resources, as well as in shaping the nature and effectiveness of fisheries management, and they have sought ways to use these resources more sustainably. 41 They have also contributed to understanding the ecological and social concerns associated with mariculture, which is increasing throughout the world as a way to compensate for declining natural resources. 42 This research also contributes to several related themes identified in this chapter, including the links between economic globalization (e.g., of industrial shrimp farming), conflicts over common property resources and loss of forest lands (mangroves); the emergence of new social institutions (social movements in resistance to industrial aquaculture); and the use of new information technologies (communications and



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