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8.01.05 - Riparian and coastal ecosystems


Jiri Kulhavy, Czech Republic


Matjaz Cater, Slovenia

About Unit

The Unit deals with the coordination of forest research particularly in three fields. (1) Riparian forest ecosystems, (2) Floodplain forest ecosystems, (3) Coastal forest ecosystems, above all mangrove forest ecosystems. Through concrete research activities, conferences, workshops, excursions and field trips are organized.

1. Floodplain forest ecosystems

A floodplain, or flood plain, is a flat or nearly flat land adjacent to a stream or river that stretches from the banks of its channel to the base of the enclosing valley walls and experiences flooding during periods of high discharge. It includes the floodway, which consists of the stream channel and adjacent areas that carry flood flows, and the flood fringe, which are areas covered by the flood, but which do not experience a strong current. In other words, a floodplain is an area near a river or a stream which floods easily.

Floodplains can support particularly rich ecosystems, both in quantity and diversity. They are a category of riparian zones or systems. A floodplain can contain 100 or even 1,000 times as many species as a river. Wetting of the floodplain soil releases an immediate of nutrients: Those left over from the last flood, and those that result from the rapid decomposition of organic matter that has accumulated since then. Microscopic organisms thrive and larger species enter a rapid breeding cycle. Opportunistic feeders (particularly birds) move in to take advantage. The production of nutrients peaks and falls away quickly; however the surge of new growth endures for some time. This makes floodplains particularly valuable for agriculture.

Markedly different species grow in floodplains than grow outside of floodplains. For instance, riparian trees (that grow in floodplains) tend to be very tolerant of root disturbance and tend to be very quick-growing, compared to non-riparian trees.
Floodplain forests are deciduous forests which exist in seasonally wet areas, most commonly on the active floodplains along major rivers and streams. The canopy and diversity can vary based on the amount of disturbance the site typically faces, especially soil and debris deposition along with erosion, which can consistently inhibit plant growth. Based on these variables, species composition may be dominated by a single species, or composed of a variety.

In the 1800s, prior to settlement, floodplain forests covered approximately 1% of the landscape. In fact, these ecosystems were so prevalent that humans as well as plants and animals have used them for migration corridors for quite some time. However, in the past century and a half, human activities, such as land clearing, wetland filling and dredging, have drastically reduced the acreage of this ecosystem. Still, floodplain forests have not been cleared as completely as other forest systems, which have provided much needed refuge for wildlife losing other habitat.
2. Riparian forest ecosystems

A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the fifteen terrestrial biomes of the earth. Plant habitats and communities along the river margins and banks are called riparian vegetation, characterized by hydrophilic plants. Riparian zones are significant in ecology, environmental management, and civil engineering because of their role in soil conservation, their habitat biodiversity, and the influence they have on fauna and aquatic ecosystems, including grassland, woodland, wetland or even non-vegetative. In some regions the terms riparian woodland, riparian forest, riparian buffer zone, or riparian strip are used to characterize a riparian zone. The word "riparian" is derived from Latin ripa, meaning river bank. The riparian is an important feature of a wetland because it allows characterization of the wetland's overall health.

Riparian zones may be natural or engineered for soil stabilization or restoration. These zones are important natural biofilters, protecting aquatic environments from excessive sedimentation, polluted surface runoff and erosion. They supply shelter and food for many aquatic animals and shade that is an important part of stream temperature regulation. When riparian zones are damaged by construction, agriculture or silviculture, biological restoration can take place, usually by human intervention in erosion control and revegetation. If the area adjacent to a watercourse has standing water or saturated soil for as long as a season, it is normally termed a wetland because of its hydric soil characteristics. Because of their prominent role in supporting a diversity of species, riparian zones are often the subject of national protection in a Biodiversity Action Plan. These also known as a "Plant or Vegetation Waste Buffer".

3. Coastal forest ecosystems

The world is composed of many different forest ecosystems that work in symbiosis with one another. Marine coastal ecosystems, which are found at the point where oceans and seas meet land, are unique and important for both humans and the environment. There are many types of marine coastal ecosystems. They include e.g. salt marshes, mangrove swamps, wetlands etc. All of these have their own unique life forms. There is a need to better understand, evaluate and monitor the goods and services provided by coastal and marine ecosystems. Unlike for most other coastal ecosystems, considerable data are available on the global distribution of mangrove forests. Based on the coastal characterization presented above, mangroves line approximately 8 percent of the world’s coastline. A previous estimate by Spalding et al. (1997:20–23) concludes that mangrove are distributed along approximately one-quarter of the world’s tropical coastlines, covering a surface area of 181,000 km2. About 112 countries and territories have mangroves within their borders. More integration and collaboration among the various agencies working in the coastal zone, particularly with the different monitoring initiatives, such as the Global Ocean Observing System (GOOS) should be encouraged (GOOS Project Office 1998 and 1999; Summerhayes, personal communication, 1999). Such organizations include the United Nations Environment Programme (UNEP), the Intergovernmental Oceanographic Commission (IOC), the United Nations Educational, Scientific, and Cultural Organization (UNESCO), the United Nations Development Programme (UNDP), the Food and Agriculture Organization of the United Nations (FAO), the International Geosphere-Biosphere Programme (IGBP), nongovernmental organizations, and academic centres.

State of Knowledge

The collection of papers entitled Alluvial Forest of Europe (Yon and Tendron, 1981) provoked considerable interest in European floodplain forest. In addition, other important papers were published later, e.g. Analysis of floodplain forests along the Morava and Thaya rivers (Czech Republic) was published in a two-volume monograph of Penka, Vyskot, Klimo, Vašíšek (1985,1991), situation of floodplain forest ecosystems was published by Klimo and Hager, 2001. Other important publications on floodplain forests include papers by Graner (1994), Piégy, Pantou and Ruffinoni (2003), Vukelič et al. (2005).
Hot topics: floodplain forest management, hydrological regime restoration, biodiversity, protection of surface water against eutrofication, retention and infiltration capacity, flooding ecology, nature conservation.