February 2 is World Wetlands Day - the anniversary of the adoption in 1971 of the Convention on the Protection of Wetlands, or the Ramsar Convention (from the city of Ramsar in Iran, where the meeting took place). Wetlands - the border between land and water - are key ecosystems for the protection of hundreds of thousands of plant and animal species, as well as some of the most important climate and water circulation regulators on earth.
This year's World Wetlands Day was celebrated under the slogan of Wetlands and biodiversity, and in the Polish version, proposed by the Wetlands Conservation Center - Life in the swamps.
The Ramsar Convention defines wetlands as "swamp, mud and peat lands or water reservoirs, both natural and artificial, permanent and periodic, with stagnant or flowing waters, fresh, brackish or salty (including sea waters whose depth at low tide does not exceed 6 m). " Such a wide approach to wetlands has a deep justification. It is impossible to clearly (spatially and functionally) separate land wetlands (swamps and floodplains) from inland water ecosystems or coastal marine waters. It is also impossible to protect swamps without protecting the surface waters associated with them, or to preserve the ecological integrity of lakes or rivers without preserving bullrush zones, riverside wetlands, or swamps regulating the hydrology of the drainage basins. Wetlands scientists define swamps as a specific type of wetland that accumulates peat - dead plant debris. Due to the saturation of the soil with water, they do not completely decompose, but accumulate in the form of often several-meter thick deposits. Swamps, therefore, is a term that is similar in meaning to peat bogs, but applies only to natural ecosystems.
The global wetlands surface is shrinking. The UN Monitoring Center for Environmental Protection (UN WCMC), commissioned by the secretariat of the Ramsar Convention, developed the WET (Wetland Extent Trends) index. The WET index (Ramsar 20181) compiles over 2,000 data strings on the area of selected wetlands from 1970 to 2015. It does not present the full change in the surface of wetlands in the world, but only the change in the surface of those facilities for which they had sufficiently accurate and long data string. For example, the data for Latin America includes almost exclusively the Caribbean, not including the Orinoco and Amazon valleys. Nevertheless, already on the basis of these available data a clear downward trend of the surface of natural wetlands can be seen in all regions of the world. The average annual rate of disappearance of natural wetland surfaces estimated by the WET index is - 0.78% per year. This is a decrease more than three times faster than the average annual rate of loss of natural forests on Earth.
More and more wetland-related species are threatened with extinction. Analysis of the IUCN Red List of Threatened Species shows that:
- of over 19,500 species dependent on wetlands around the world, 25% are endangered species;
- if only species related to inland wetlands are considered - also 25% are globally endangered;
- among plants and animals related to inland wetlands, the most endangered species in the world are river and stream dependent species - 34% of them are endangered species.
The disappearance of wetlands is also aggravating the climate change. After draining, the peat bogs change from carbon dioxide accumulators into sources of its emission into the atmosphere. In turn, the acceleration of water flow, caused by the liquidation of swamps, intensifies droughts. The expert opinions are unambiguous: without immediately stopping the destruction of wetlands and restoring those already transformed, we will not limit the ecological and climate crisis, nor will we adapt to the changing environment.
Wetlands clean the water - bacteria and swamp plants play an important role in this process. Natural rivers or those close to natural, with coastal wetlands, have a high capacity for self-purification. However, if the wetlands that form buffer zones between agricultural land and the river are destroyed, the biogenic elements (nitrogen and phosphorus from fertilizers) flow from the fields directly into the river. As a consequence, algal blooms and oxygen deficiencies appear in the water in the lower sections of the rivers, as well as in marine coastal waters. The restoration of riverside wetlands, meandering riverbeds, restoration of connections of floodplains with riverbeds are elements of river renaturization programs, which aim, among other things, at reducing flood risk, reducing the severity of drought, and improving water purity in rivers, lakes and seas.
For more information on the celebration of World Wetlands Day 2020, visit the Wetland Protection Center website: bagna.pl/
Based on press material and with the consent of its authors: dr hab. Ewa Jabłońska and dr hab. Wiktor Kotowski from the Wetlands Protection Center and the Faculty of Biology at the University of Warsaw.
Photo by Jerzy Malicki