Long-term environmental trends and the future of tropical wetlands

Abstract

Tropical wetlands assume important functions in the landscape and contribute considerably to the welfare of large parts of the human population, but they are seriously threatened because they are considered free resources of land and water. This review summarizes long-term environmental trends for tropical wetlands and predicts their future to the time horizon 2025. Many tropical countries do not have the economic strength, scientific and technological capacity, and/or administrative infrastructure to adequately react to the challenges of increasing population pressure and globalization of the economy with respect to the sustainable use of the resources. Furthermore, political instability and armed conflicts affect large areas in several tropical countries, hindering wetland research and management. Detailed wetland inventories are missing in most countries, as are plans for a sustainable management of wetlands in the context of a long-term integrated watershed management. Despite large regional variability, a continental ranking shows, in decreasing order of wetland integrity, South America, Africa, Australia and Asia, while efforts to mitigate human impacts on wetlands are largest and most advanced in Australia. Analysis of demographic, political, economic and ecological trends indicates fairly stable conditions for wetlands in tropical Australia, slight deterioration of the large wetland areas in tropical South America excepting the Magdalena and Cauca River flood plainswhere human population is larger, rapidly increasing pressure and destruction on many African and Central American wetlands and serious threats for the remaining wetlands in tropical Asia, by the year of 2025. Policy deficiencies, deficient planning concepts, limited information and awareness and institutional weakness are the main administrative reasons for wetland degradation and must be overcome to improve wetland management and protection in future. Intensification of international cooperation and assistance is considered of fundamental importance for most tropical countries to solve problems related to wetland research, protection and sustainable management. Figure 2 Major wetlands of tropical and subtropical South America (according to Junk 1993).

To connect or not to connect? Floods, fisheries and livelihoods in the Lower Rufiji floodplain lakes, Tanzania

“…In general, wetlands are considered to be the most valuable terrestrial ecosystems (Costanza et al 1997). In spite of this, tropical wetlands are amongst the natural ecosystems with the highest rate of conversion (mainly for irrigated agriculture), especially in Africa (Junk 2002). This is due, at least partly, to a lack of data on and understanding of their multiple use values (Barbier 1994).…”

Diversity and structure of microcrustacean assemblages (Cladocera and Copepoda) and limnological variability in perennial and intermittent pools in a semi-arid region, Bahia, Brazil

“…Evaporation during the dry season reduces the volume of the water body and affects the availability and quality of the resources (Junk, 2002;lake, 2003). These variations constrain the potential pool of community members by eliminating species that are unable to cope with the resulting physical stress (WellBoRn et al, 1996).…”

Microbial and Physicochemical Qualities of River Owena Water: An Important Source of Domestic Water in Owena Metropolis

“…Additional benefits of the reservoirs are tourist attraction and opening up of new areas for development (Kitur, 2009). According to Junk (2002) and Dudgeon (2006), freshwater ecosystems are vulnerable to human impacts, hence they are likely to be influenced by reservoir catchment activities. This is because terrestrial ecosystems have linkages with aquatic ecosystems (UNEP, 2000).…”