Exactly 51 years ago, on February 2, 1971, the Convention on Wetlands of International Importance (Unesco, 1971) was held in the Iranian city of Ramsar, on the shores of the world’s largest lake, the Caspian Sea, and since 1997, on the same date, World Wetlands Day is commemorated.
A wetland is a type of terrestrial ecosystem that, either permanently or intermittently depending on the time of year, is partially or totally flooded by water . Among them, therefore, we can include swamps, peat bogs, swamps, rivers, lakes and lagoons, but also brackish or salt water marshes, lagoons, beaches, coral reefs, mangroves and other shallow marine littoral zones. Of course, those artificial ecosystems closely linked to water, such as ponds, salt pans or reservoirs, are also considered wetlands.
The very nature of these environments, with a hybrid aspect between the typically terrestrial ecosystem and the aquatic one, means that types of environments have a series of particular characteristics, different from those found in any other ecosystem. Within wetlands, moreover, there may be a great variety of different ecosystems. In the body of water of a lake, for example, we would have three zones: the coastal waters, which is the closest to the coast; the photic zone, which is the surface part of open water that is well served by sunlight, and the deep water zone, where sunlight is attenuated. In addition, we also have several zones in what refers to the soil, or benthic zone; the littoral benthic zone, which corresponds to the water zone of the same name; the slope, which usually has a more or less pronounced slope and functions as a transition between one zone and the next, and the deep benthic zone, which corresponds to the bottom of the lake. And we must not forget the so-called epilittoral zone, which is the land shore where the influence of the lake is only underground. Each part of the lake —or any other wetland— is connected to the rest of the parts, but in each case, specific ecological relationships take place.
All of this makes wetlands places of high ecological importance , and not only because of their role in regulating the water cycle, and in some cases, such as peat bogs, because they retain large amounts of carbon . In addition, and especially, for being very rich and diverse in species, and one of the most productive types of ecosystem. To such an extent, some scientists speak of wetlands as biological supermarkets, due to their role in supporting complex ecological relationships and their richness. The remains of plants that fall into the water form small particles of organic matter called detritus when they degrade. When decomposed, it nourishes algae and aquatic plants and feeds small fish , aquatic insects and other invertebrates, which find shelter and protection in the bottom vegetation. These animals in turn are food for larger fish, reptiles, amphibians, and even birds and mammals.
The balance of a wetland depends on these ecological relationships being maintained, but also on climatic factors such as rainfall. These types of ecosystems are very sensitive to changes; A massive contribution of decomposing organic matter can produce an accumulation effect, called eutrophication, which clouds the waters and prevents the plants and algae from developing on the bottom, destabilizing the ecosystem. A severe drought, or other extreme events fueled by climate change, can cause serious damage to these habitats, or even make them disappear. This high sensitivity is added to the fact that a large number of threatened species depend directly or indirectly on wetlands. Without adequate protection of this type of habitat, many of the species in danger of extinction could disappear.
But not all effects are ecological. Wetlands are estimated to be among the ecosystems that provide the most economic value . Among the consequences of poor conservation of wetlands are, therefore, serious socioeconomic impacts. These include reduced access to fresh water for people, food and energy shortages, floods that can cause irreparable damage, and a loss of our resilience to climate change.
Among the impacts that damage wetlands, especially inland ones, include fishing, agriculture, livestock and forest-type exploitation , but also oil exploitation, urbanization, the improper extraction of water in the form of illegal wells and industrial discharges. The de facto protection of these habitats (and not only de jure) should limit or eliminate these activities, both in the wetland itself and in its surroundings. Because what is the use of holding a convention on wetlands and their importance, if we do not then make enough efforts to preserve them?
Costanza, R. et al. (1997) ‘The value of the world’s ecosystem services and natural capital’, Nature, 387(6630), pp. 253–260. doi:10.1038/387253a0.
Goswami, M.R. and Mukhopadhyay, A. (2022) An Overview of the Determination of Biodiversity of Wetlands, Handbook of Research on Monitoring and Evaluating the Ecological Health of Wetlands. IGI Global. doi:10.4018/978-1-7998-9498-8.ch009.
Nayak, A. and Bhushan, B. (2022) Wetland Ecosystems and Their Relevance to the Environment: Importance of Wetlands, Handbook of Research on Monitoring and Evaluating the Ecological Health of Wetlands. IGI Global. doi:10.4018/978-1-7998-9498-8.ch001.
Tari, V.S., Gupta, R. and Siddiqui, N. (2022) Impact of Climate Change on Upper Ganga Ramsar Site of UP, India: Sustainable Restoration of Wetland Ecosystem, Handbook of Research on Monitoring and Evaluating the Ecological Health of Wetlands. IGI Global. doi:10.4018/978-1-7998-9498-8.ch006.
Unesco (1971) Convention on Wetlands of International Importance, especially as Waterfowl Habitat. Available at: https://www.miteco.gob.es/es/biodiversidad/temas/ecosistemas-y-conectividad/conservacion-de-humedales/ch_hum_convenio_ramsar.aspx (Accessed: 14 January 2022).