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Glossary
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Abiotic
Nonliving (usually refers to substances or environmental factors).
Abrasion
The operation of wearing away of a surface by rubbing and friction (by river, wave, ice, or wind action). The attack of the sea on the land. Currents of water laden with sand, shingle and other rock-debris are the chief abrading agents in nature.
Acidification
The process of becoming more acid.
Acidophilous
Thriving in an acidic environment.
Accumulation
Deposition of rock material by which the surface is appreciably raised, either locally or regionally.
Algae
Collective name of large group of chlorophyll-containing plants, comprising the sea-weeds and various freshwater forms, ranging in size from single cells to long stems.
Algae bloom
Dramatic increase in alga growth resulting from high levels of nutrients or pollutants.
Alkaloid
One of a large group of nitrogenous bases of vegetable origin. Many alkaloids are used as drugs, e.g. morphine, quinine and strychnine.
Alluvial
Formed by river flow processes, e.g. alluvial plain.
Alluvial terrace
A terrace formed when a river incises into its own valley fillement.
Alluvium
Sediment deposited by flowing water.
Anadromous fish
Fish that hatch in freshwater, migrate to the ocean, mature there and return to freshwater to spawn (lay their eggs). Salmon and steelhead, for example.
Anaerobic(also anoxic)
Lacking oxygen. Anaerobic organisms need an environment without oxygen.
Angiospermae (or angiosperms)
Those spermatophytae in which the seeds are contained in an ovary.
Anthropogenic
Of human origin or relating to man.
Anticyclone
An atmospheric high pressure cell involving the divergence of air, which subsides at and flows spirally out of the centre.
Aquaculture
Fish or seafood farming.
Aquatic Beds
Aquatic beds are an extremely diverse group of communities. They are found in fresh water or saline environments as well as in shallow or deep water. Each of the five major systems includes aquatic beds as one of its classes. Marine and estuarine environments are characterised by an abundance of algae. Some of the more common types include rock-weed, wrack-weed, sea lettuce and kelp. Vascular plants found in these areas include surfgrass, shoalgrass and eelgrass.
Aquatic plants
Emergent plants, such as sedges, reeds and rushes, rooted in the sediment and protruding above the water surface. Free-floating plants, such as water fern, floating at the water surface. Floating leafed plants, such as water lilies, rooted in the sediment with leaves floating on the water surface. Submerged plants, such as najas, growing below the water surface.
Aquifer
A saturated permeable geologic unit that can transmit significant quantities of water under ordinary hydraulic gradients. An underground layer of rock, sand or gravel which holds water and allows. Water to percolate through
Aquitard
A less permeable geological unit. Its permeability might be high enough to transmit water in quantities important in the regional groundwater flow but insufficient for production well.
Artificial wetlands
Wetlands constructed by humans.
Assessment
The word assessment is used in a generalized way for the estimation of the magnitude or quality of the way in which one function or activity affects another function or activity (see also evaluation).
Autotrophic
Autotrophic organisms are self nourishing which are able to feed on simple inorganic substances and through fixation of light energy, build up more complex substances. They are mostly green plants.
Basic metabolism
Amount of energy captured by an organism (or trophic level) and used for processes to keep the organism(s) alive including the part released into the environment as heat (and transpiration). Or the total amount of energy captured minus the part transferred to a higher trophic level and invested in reproduction and growth.
Bedrock
Unbroken solid rock, usually overlain by rock fragments or soil.
Benefits transfer
The practice of using values estimated for an alternative wetland site as a basis for estimating a value for the site in question.
Benthic organisms (or benthos)
Those organisms attached to, living on, in or near the sea bed, river bed or lake floor (e.g. pertaining to the bottom of a body of water).
Bifurcation
A division into two more or less equal river branches.
Biogeographical region
Any geographical area characterized by their distinctive flora and/or fauna.
Biogeography
The study of the geographical distribution of organisms, their habitats and the historical and biological factors which produced them.
Biological diversity or Biodiversity
The variability among living organisms of different origin. This includes terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part of. It also includes the diversity within species, between species and of ecosystems.
Biomass
Biomass is the total quantity or weight of living material (plants or animals) in a given area, usually expressed in dry weight of an organism, a population, or a community. Biomass consists of vital elements for life: carbohydrates or glucose, amino acids, ATP (= adenosine triphosphate, a high energy storage material), proteins and other vital materials.
Biome
An area that has a certain kind of community of plants and animals.
Biosphere
The biosphere is that part of the earth where life exists naturally. Dasmann (1976) defines it as the thin layer of soil, rock, water and air that surrounds the planet Earth along with the living organisms for which it provides support, and which modify it in directions that either enhance or lessen its life-supporting capacity. Some writers distinguish the biosphere (life), hydrosphere (water), atmosphere (air) and lithosphere (rock, the crust of the earth). As used here, the biosphere includes those parts of the hydrosphere, atmosphere and lithosphere that contain living organisms. In vertical dimension it extends from the deepest trenches in the ocean floor, more than 11,000 meters below sea level, to at least 10,000 meters above sea level, where spores (reproductive cells) of bacteria and fungi can be found floating free in the atmosphere. By far most living things exist in the narrower region extending from the limit of penetration of sunlight in the clearest oceans, less than 200 meters from the surface, to the highest level of the permanent snow line in tropical and subtropical mountain ranges, about 6.000 meters. By any definition, the biosphere is as a mere film in thickness compared to the size of the radius of the earth (about 6,370 kilometres).
Biota
Animal and plant life.
Biotic community (see Community)
Biotope
The smallest geographical unit of the biosphere or of a habitat that can be delimited by convenient boundaries and is characterized by its biota.
Bivalves
Invertebrates such as oyster, clam or mussel that have two shells hinged together.
Blue-green algae
see Cyanobacteria
Bogs
Waterlogged peatlands in old lake basins or depressions in the landscape, forming where peat accumulation exceeds decomposition as a result of climatic conditions. Bogs are precipitation dominated because the accumulated peat formations elevate the system surfaces sufficiently relative to the surrounding landscape that there are few or no surface inflows. Since bogs do not receive nutrients or organic matter transported by surface water, they have low rates of primary productivity and decomposition. Bogs are typically acidic because the dominant living plant matter, Sphagnum moss, releases H+ ions (acidity), and the peat releases organic acids. The pH in bogs can be as low as 3.0 4.0. Their flora bears much in common with arctic tundra - despite the fact that they often develop in relatively warm climates. Bog vegetation is often surprisingly diverse. In arctic tundra the "ground" from which it develops is illusory: although the surface may appear solid, it is often nothing more than a floating mat of Sphagnum moss which quakes underfoot. Such mats are strong enough that they are able to serve as a growing surface for many types of plants even small trees and shrubs. Besides of the dominant ground covers of graminoids and heaths bogs have specialised and unique flora that has evolved in their nutrient-poor and acidic conditions. An example of this unique flora is the carnivorous pitcher plant, which obtains nutrients from the flies it traps.
Brackish
Slightly salty. A mixture of fresh and saltwater typically found in estuarine areas.
Brackish Tidal Marshes
Brackish tidal marshes are river-associated estuarine environments found upstream from salt marshes. These systems are often referred to as "euryhaline" a term, which refers to the tendency for the systems salinity to change in response to tidal motion. When tides are highest, salinity may be around 3% (roughly that of ocean water) and 0.05% or less (approximately that of freshwater) during the lowest tide. The areas most affected by salts are the least diverse. These communities are composed mostly of cattails and bulrushes. Vegetation further upstream is similar to what would be expected in a typical freshwater marsh. Some of the more common species are wild rice, mallows, arrowhead, sedges as well as cattails and bulrushes.
Carnivore
An animal that eats flesh (in comparison with herbivorous and omnivorous).
Carrying capacity
The carrying capacity of a given area for a certain type of use can be defined as the capacity to provide space, resources and suitable environmental conditions in a sustainable manner. IUCN, UNEP and WWF (1991) define it as the capacity of an ecosystem to support healthy organisms while maintaining its productivity, adaptability, and capability of renewal. The biological carrying capacity is the number of individuals of a particular species that the resources of an environment or ecosystem can support.
Catadromous
Fish that mature in freshwater but migrate to seawater to spawn (lay their eggs). American eel, for example.
Catchment area (or, in North America, watershed)
An entire tract of country drained by a river and all its tributaries.
Channel
An open conduit either naturally or artificially created which periodically or continuously contains moving water, or forms a connecting link between two bodies of water. River, creek, run, branch and tributary are some of the terms used to describe natural channels. Canal and floodway are some of the terms used to describe artificial channels.
Channelization
Channel alterations for the purpose of increasing flow and decreasing retention time, including re-sectioning, realignment, diversion, embankment, bank protection, channel lining, and culverting by dredging, cutting, and obstruction removal.
Chernosynthesis (see also Photosynthesis)
As photosynthesis but with use of chemical energy instead of sunlight.
Chernozem
Dark well drained grassland soil granular and rich in humus to some depth, with or without concentration of clay in the B-horizon, and calcareous below. This type of soil is formed beneath steppe and forest-steppe vegetation in the sub-boreal zone.
Climax
The local end point of a sere (of a succession). A more or less stable biotic community which is in equilibrium with existing environmental conditions and which represents the terminal stage of an ecological succession.
Community
A biotic community is any assemblage of populations of plants and animals inhabiting. Common area and affecting one another. A combination of such a biotic community with the physical environment that supports it is called an ecosystem. A short definition may read the living part of an ecosystem.
Conservation (see also In-situ conservation)
Conservation means literally protection against undesirable changes. In IUCN, UNEP and WWF (1991) conservation is defined as the management of human use of organisms or ecosystems to ensure such use is sustainable. The word conservation is used in a variety of ways, for example in relation to energy conservation, resource conservation or the conservation (maintenance) of, the production level of a given commodity. In the sense of nature conservation, it means the protection of the natural environment against undesirable changes. Thus, as with the term environment, it must always be made clear, what type of conservation is meant to avoid confusion, which is especially important when using the term conservation in combination with the term sustainable development (see further). In relation to resource use conservation means the wise use of natural resources should involve the planned management of ... the resources to deter or prevent over-exploitation, irreversible destruction, or neglect.
Contracting Parties
Countries that are Member States to the Ramsar Convention on Wetlands, 119 as of 1st March 2000. Membership in the Convention is open to all states that are members of the United Nations, one of the UN specialised agencies, or the International Atomic Energy Agency, or is to a Parry to the Statute of the International Court of Justice.
Cotyledon
The seed leaf: that is the leaf or leaves which first appear when the seed germinates.
Criterion
Principle or standard that it thing is judged by.
Cryptobiota
The ecological processes and functions of the soil biota and soil subsystems are important determining factors for productivity of ecosystems agricultural- and forestry systems. The micro- (e.g. bacteria and fungi) and macro- (vertebrates) biological activities are essential for the nutrient cycli and balances and play indirectly an important role in the soil fertility and stability. In 1 gram of fertile soil some 2.5 billion bacteria, 400.000 fungi, 50.000 algae and 30.000 protozoa can be found. Mono cultures (systems in which the vegetation is replaced by one crop species) experience a net loss of soil nutrients and minerals. This loss is for its major part not harvested, and is only compensated by high inputs and investments like fertilizers.
Cyanobacteria
Single-cell or filamentous organisms, also known as blue-green algae that are able to convert the atmospheric nitrogen into forms that can be utilized for plant growth.
Decomposers
That group of organisms (bacteria and fungi), which degrade dead organic material in ecosystems.
Deciduous
Falling at the end of growth period or at maturity. Regarding trees: those having leaves that all fall at a certain time of the year.
Decomposition
Metabolic degradation of organic matter into simple organic and inorganic compounds, with consequent liberation of energy.
Delta
A deposit of sediments made by a stream at the place of its entrance into an open body of water (such as a lake or ocean), resulting in progression of the shore line. The mouth of a stream with numerous arms, channels and shallows formed by intensive alluviation.
Denudation
A combined effect of all processes of terrestrial degradation, including weathering, transportation, chemical and mechanical action of running water and the mechanical action of wind.
Deoxigenation
Depletion of oxygen.
Detritus
Small pieces of dead and decomposing plants and animals. Detached and broken down fragments of a structure.
Developing country
A country that has not yet reached the stage of economic development characterised by the growth of industrialisation, nor a level of national income sufficient to yield the domestic savings required to finance the investment necessary for further growth.
Development(see also Sustainable development)
The word developmentrefers both to a process (the gradual unfolding of it potential) and to a stead state (the more elaborate form of a product). In the conservation versus development debate, usually the process interpretation is used. OAS ( 1987 ) defines development as the use, improvement and/or conservation of system. Goods and services and the mitigation of hazardous events. IUCN, UNEP and WWF (1991) define development as increasing the capacity of the environment to meet human needs and improve the quality of human life.
Diatoms
Single-celled algae found in most waters. Each cell is surrounded by two overlapping silica plates, which show characteristic patterns. Diatoms are very important in food chains and are extremely productive.
Direct use value
The value derived from direct use or interaction with a wetlands resources and services, such as the value of fish catches.
Discount rate
The rate that determines the present monetary value of future benefits that will accrue from an investment, or a measure of revenue or income that will be lost through receipt of monetary returns in the future rather than now. High discount rates tend to inhibit conservation and facilitate development (conversion) of natural environments.
Dissolved oxygen
Oxygen dissolved in water and available to aquatic organisms. Concentrations below 5 mg/l are stressful and may be lethal to many fish and other species.
Distributary
A river branch flowing away from the main stream of a river and not rejoining.
Disturbed area
Area where vegetation, soil or hydrology have been significantly altered, making wetland determination difficult.
Diversion
Type of channelization in which flow is diverted around an area to be protected
Diversity
Genetic diversity
Dredging
The scooping, or suction of underwater material (e.g., sediment) from a harbour, or waterway. Dredging is one form of channel modification.
Ecological functions of wetlands
Activities or actions which occur naturally in wetlands as a product of interaction between the ecosystem structure and processes.
Ecological processes
A continuous action or series of actions that is governed or strongly influenced by one or more ecosystems.
Ecology
The word ecology is derived from the greek oikos, meaning house or place to live. Literally, ecology is the study of organisms at home. Usually, ecology is defined as the study of the relation of organisms or groups of organisms to their environment, or the science of the interrelations between living organisms (plants, animals and micro-organisms) and their non living environment. Another definition of ecology reads the study of the structure and functioning of nature, it being understood that mankind is a part of nature. Ecology is not a new science. The word was first used by Ernst Haeckel in 1869, but ecological studies have been carried out since antiquity.
Ecosystem
An ecosystem is any unit limited in space that is made up of a biotic community interacting with the physical environment so that a flow of energy leads to a clearly defined trophic structure (food chain) and material cycles within the system. The interaction between living organisms and material cycles within an ecosystem has, to a certain degree, the power of self-regulation. Ecosystems may be small and simple, such as a small isolated pond, or large and complex, such as a specific tropical rain forest or coral reef in tropical seas. The spatial borders of ecosystems are defined as the space (or surface) in which endogenous ecosystem processes take place. A stabile ecosystem is characterized by balanced transfer-cycle of natural resources such as: water, gasses, energy, nutrients and organisms. Ecosystems do not have an intrinsic objective or goal (such as maintaining a number of species diversity). But ecosystems just produce, transform and transport energy and matter.
Ecotone
The boundary or transitional zone between two adjacent community types (for example, such as grassland and forest) characterized by structural or functional discontinuity. Tension zone where two ecosystems overlap, and which supports species from both ecosystems as well as species found only in this zone. Ecotones are often species-rich as they receive immigrants from both sides.
Ecotope
A particular kind of habitat within a region. The total relationship of an organism with its environment, being the interaction of niche, habitat and population factors.
Efficiency
Biological efficiency is the ratio of the productivity of an organism or population to the energy consumed. Ecological efficiency is the efficiency of transfer of energy from one trophic level to the next. Economic efficiency is the allocation of resources in the economy that yields an overall net gain to society as measured through valuation in terms of the benefits of each use minus its costs.
Embankment
Type of channelization in which a levee, bund, or dike is used to prevent the flow from overflowing onto the floodplain. Fill material, usually earth or rock, placed with sloping sides and usually with length greater than height. All dams are types of embankments.
Emergent Wetlands
Emergent wetlands, better known as marshes, are usually dominated by grass-like plants such as cattails, sedges or bulrush that are rooted in bottom sediments, but "emerge" above the surface of the water. Despite their diversity (e.g. salt marshes, brackish tidal marshes, cattails filling in old oxbow lakes, prairie potholes), all marshes share two features in common: All marshes contain emergent vegetation. They tend to develop in zones progressing from terrestrial habitat to open water.
Endangered Species
An animal, plant or insect species whose numbers are so low, compared to historic levels, that it is in danger of extinction, and that is awarded protection under the national Endangered Species Acts.
Endemic
A species found in only a single geographical area and nowhere else is said to be endemic to that area.
Endogenous
Formed within the considered ecosystem (area).
Environment (human)
The term environment cannot stand on its own and should always be used in combination with a given object, region, or condition. It is defined by OAS (1987) as a set of natural, social, cultural values, which exist in a given place and point in time that influences the material and psychological life of man. Thus environmentclearly means much more than nature and/or natural resources while the natural world is but one aspect of the total human environment.
Environmental conservation
The rational use of the environment to provide the highest sustainable quality of living for humanity.
Environmental functions
The capacity of natural processes and components to provide goods and services those directly or indirectly contribute to human welfare.
Environmental impact (in the negative meaning)
Negative environmental impacts are the result of any activity of development
Environmental management (positive environmental impact)
The planning and implementation of actions geared to improve the quality of the human environment.
Ephemeroptera
That order of insects including of mayflies, whose adult life is very short, sometimes less than a day. They have an aquatic nymph (larval) stage. They have three appendages, tails, projecting from the end of the abdomen, and the hind wing is smaller than the fore wing. They are distinguished by four pairs of membranous wings of which the anterior pair are usually triangular in shape.
Equilibrium
The ecological functions and processes in the Life Support System contain a large number of buffer- and feedback- or control mechanisms. These mechanisms make that the ecological equilibrium oscillates around a mean value.
Erosion
The process of wearing away of the lands by running water, winds, glacial ice, and waves. In areas with little vegetation or poorly developed soil, the rate of erosion can be greatly increased.
Estuarine
Estuarine wetlands contain a mixture of freshwater and ocean water. They are typically located in areas where freshwater rivers flow into the ocean. Major estuarine systems include the salt marshes, brackish tidal marshes and mangrove swamps.
Estuary
A passage, as the mouth of a river or lake, where the tide meets the river current. More commonly, an arm of the sea at the lower end of the river. According to physical circumstances a river on reaching the sea may broaden out and flow into its estuary, or divide and deposit materials to form a delta.
Eutrophication
A process of over enrichment of a water body with nutrients (usually nitrates and phosphorus). The rapid increase in nutrient levels stimulates algae blooms. Bacterial decomposition of the excess algae depletes oxygen levels seriously. The extremely low oxygen concentrations that result may lead to the death of fish, creating the further oxygen demand and so leading to further deaths.
Evaluation
Means the determination of the value (numerical expression) of something, e.g. the (socio economic) value of environmental functions to human society.
Evaporation
Loss of water from a free water surface or from the soil surface by vaporization.
Evapo-transpiration
Water transmitted to the atmosphere by a combination of evaporation and transpiration.
Evolution
A change in the genetic make up (allele frequencies) of a population over time (see also genetic diversity).
Exogenous
Taking place outside the ecosystem (area).
Feedback
Return of an output signal from one stage or level of the ecosystem back to the input or lower level of the system, by which modification or control of a process or the system is acquired. Positive feedback = signal system which returns back to the lower level and influences the factors which amplifies the output (a male becoming aggressive in a room with other males arouses aggression of the other males, which on their turn stimulate more aggression of the first male etc.). Negative feedback = signal system which turns back to the former level and influences the factors which controls the output ( the only woman in the room reacts to the aggression of the first man by calming down, starting to entertain the men and controlling the first man to become less aggressive).
Fens
Fens are peat-accumulating wetlands that form at low points in the landscape or near slopes where ground water intercepts the soil surface. Water levels are fairly constant all year because the water supply is provided by ground water inputs. Fens, like bogs, tend to be glacial in origin and are found, for example, in the northern United States or on mountains and mountainsides. Fens are dominated by herbaceous plants, such as grasses and sedges, typically lack the Sphagnum moss that predominates in bogs, and look like meadows. Fens may represent an earlier successional stage of peat accumulation than bogs, and over geologic time, fens may become bogs. Unlike bogs, fens receive minerals and nutrients from ground water, because they have built up less peat and ground water is still sufficiently close to the surface. Fens are less acidic than bogs because they have little or no Sphagnum, and because ground water inputs tend to be neutral or alkaline. The pH of fens ranges from 4.0 - 8.0, depending on vegetation and peat type. Fens provide less stressful growing conditions for plants and microbes and thus have higher primary productivity and a greater variety of flora and fauna than bogs. Fens may depend on aquifers that are recharged in uplands. These upland recharge areas may be distant from the wetlands. Thus, excessive withdrawal or interception of ground water for municipal and agricultural uses, and reduced urban ground water recharge as a result of increased impervious surfaces can decrease water supply to fens, potentially leading to degradation of these wetland communities.
Floodplain
The land area of a river valley that is flooded at high water but is above the low water stage. Floodplain communities, despite their proximity to rivers, are classified as palustrine wetlands. The rationale for this is that riverine communities are exposed to flowing water while palustrine wetlands as well as floodplains contain more or less still water. Floodplains provide numerous benefits to society, not least of which is their capacity to check flood events. As long as a river is constricted to a channel, the height and velocity of its water will rise rapidly in response to storm events. However, as soon as a rivers water has exceeded its banks and enters a floodplain it is forced to spread out losing most of its velocity and capacity for rising in the process.
Fluviatile
Influenced or characterized by rivers or found in or near rivers.
Food chain
Subsequent steps (of energy flow) through the different trophic levels indicating specific species directly depending upon specific species in the lower trophic level.
Food pyramid
Graphical expression of the fact that total biomass of each subsequent higher trophic level is less than the total biomass of a lower trophic level. Due to the basic metabolism of organisms at each trophic level only a small proportion of energy (biomass) is transferred to the next higher trophic level.
Food web
Accurate description of the organisation of biological communities in which species are linked through complex feeding relationships.
Forested and Scrub-Shrub Wetlands
Forested and scrub-shrub wetlands are usually referred to as "swamps". Swamps are highly variable systems. Some such as the cypress swamps of the southern United Statesmay be flooded for months, or even years on end while others, such as hardwood swamps or floodplains may be flooded for only relatively short periods each year. Although most North American swamps are fresh-water, salt-water swamps known collectively as mangrovesare abundant in both tropical and subtropical areas such as Florida, Hawaii and the Virgin Islands. The dominant vegetation in swamps is also highly variable. Some swamps are dominated by shrubby vegetation (i.e. woody plants less than 6 meters in height), while others are forested (i.e., dominated by woody vegetation in excess of 6 meters). Some are dominated by broad-leaved deciduous vegetation, such as buttonbush, or silver maple. Others, such as North Carolinas pocosins might be dominated by broad-leaved evergreens such as holly or bay-berry. Canadas taiga is dominated by needle-leafed evergreens, while Louisianas cypress swamps are dominated by deciduous conifer. Even swamps composed primarily of dead wood provide important habitat for many species.
Freshwater Marshes
Marshes are one of the broadest categories of wetlands and in general harbour the greatest biological diversity. They are characterised by shallow water, little or no peat deposition, and mineral soils. Marshes are dominated by floating-leafed plants (such as water lilies and duckweed) or emergent soft-stemmed aquatic plants (such as cattails, arrowheads, reeds, and sedges). Marshes form in depressions in the landscape, as fringes around lakes, and along slow-flowing streams and rivers (such riparian marshes are also referred to as sloughs). Marshes are frequently or continually inundated with water. Marshes derive most of their water from surface water, including streams, runoff, and overbank flooding. However, they receive inputs from ground water as well. Environmental conditions in marshes lead to high productivity since the pH of most marshes is generally circumneutral and nutrients derived from runoff are plentiful. In a typical freshwater marsh the following vegetation sequence occurs: First, the "wet-meadow", or "sedge-zone" occurs. Although this area is typically not flooded, it is almost always saturated. It is typically dominated by grasses, sedges and smart weeds and may be adorned with colourful flowers such as purple loose-strife and swamp rose mallow. Beyond the wet-meadow a zone of persistent emergents occurs. These are plants such as cattail and bulrush, which remain standing above the waters surface throughout the year. Beyond this zone the non-persistent emergents occurs. These are plants such as spatter-dock and American lotus which fall below the surface of the water at the end of each growing season. Beyond this zone and just before entering deep-water the aquatic beds lie which are dominated by submergents, such as Elodia.
Freshwater systems
Freshwater systems rivers, lakes, streams, bogs and so on include fewer types of algae and a wider diversity of rooted vascular plants. Most of the algae are referred to as "stonewarts". This is a peculiar group of plants: They are frequently found encrusted with calcium carbonate. This is believed to serve as protection both from excessive solar radiation and as a deterrent to grazing by aquatic animals. Vascular submergents, such as Elodia and water milfoil are thin and feathery in appearance.
Gene pool
The sum total of all the genetic information encoded within all the genes of a breeding population.
Geomorphology
A discipline which studies genesis and evolution of landscape features.
Global warming (and greenhouse effect)
Increased global temperatures caused by human activities that enhance the atmospheric greenhouse effect. Various trace components of the atmosphere (including carbon dioxide, methane and nitrous oxide) reabsorb and retain certain wavelengths of heat radiated from the Earths surface. Human activities burning of fossil fuels and land-cover change (especially deforestation) have increased the tropospheric concentrations of all of these compounds, while adding a new class of greenhouse gases, the chlorofluorocarbons (CFCs).
Glume
A bract, particularly one of a grass. Bract is a small leaf on a floral stem often closely pressed to the base of the flower and sometimes brilliantly coloured and frequently mistaken for a petal.
Glumiflorous (maybe also glumifloral)
Having flowers with glumes or bracts at their base. Sedge, for example.
Graminoids
Grasses, herbs.
Gregarious species
Species that tend to live in a group.
Gymnosperms
A large group of seed-bearing woody plants, having seeds not enclosed in an ovary, but borne on the surface of the sporophylls. Pine-tree, fir-tree, cedar, for example.
Habit
The external appearance aspects of growth and form of an organism.
Habitat
The local environment occupied by an organism (species/ sub-species).
Helophyte
Perennial plants with renewal buds, commonly on rhizomes, buried in soil or mud below water level. Any marsh or bog plants.
Herbivorous
Feeding on plants.
Heterotrophic
Heterotrophic organisms derive their nourishment from outside (not autotrophic). They are chiefly animals, which ingest other organisms or organic matter.
Homogenisation
Changing something so that its parts become similar.
Humidity
The amount of water contained in the air (for example, 90% humidity).
Humification
The process whereby the dead bodies of plants and animals are reduced to finely divided organic material in the soil. The process by which plant detritus is turned into humus.
Humus
Decomposing organic matter in the soil.
Hydrology
A discipline which studies water distribution and cycles in nature, in term of time and space, and its physical, chemical and biological properties.
Hypolimnion
The cold bottom water zone below thermocline in a lake or reservoir.
Indicator species
Species, which indicates, due its occurrence, density or conditions a certain quality state of the ecosystem or environment. Often a very obvious or easy to monitor species, which however does not necessarily play important (key-role) role in the ecosystem processes.
Indirect use value
Indirect support and protection provide to economic activity and property by the wetlands natural functions, or regulatory environmental services, such as flood prevention.
In-situ conservation
In-situ conservation aims to preserve ecosystems to that processes, habitats and species can continue to evolve in a natural manner. Protected areas have been one of the main ways of ensuring in-situ conservation.
Inter-tidal
The area between the high and low water marks which is exposed as low tide.
Intrinsic value
The worth of something in itself regardless of whether it serves as an instrument for satisfying individuals needs and preferences.
Invertebrates
A living creature (animal) that does not have a backbone.
Juvenile
The early stage in the life cycle of anadromous fish when they migrate downstream to the ocean.
Kettleholes
Kettleholes, which serve as a sort of "geological mold" for many eastern bogs are products of the Pleistocene glaciations. As glacial ice moved, large chunks of ice would occasionally break away ("calve"), become buried in the sediments, or pressed into the earth when the glaciers re-advanced. When the glaciers finally began to retreat, these chunks of ice were left to melt, effectively producing "glacial lakes" setting the stage, as it were, for the evolution of the bog ecosystem.
Key(stone) species
Certain species within biological communities which are determining the ability for other species to persist and or which are essential in providing crucial ecological processes. The dominant predator that control populations and processes in ecosystem. In the case of beaver, the dominant herbivore that controls stream processes.
Lacustrine
The term "lacustrine" is related to the word "lake" thus a lacustrine wetland is, by definition lake-associated (i.e. living or occurring on or in lakes, also of a lake). This category may include freshwater marshes, aquatic beds as well as lakeshores. Distinctions between lacustrine and palustrine habitat are primarily contingent of the way in which lake is defined. The Lacustrine System includes wetlands and deep-water habitats with all of the following characteristics: situated in a depression or a dammed river channel, lacking trees and shrubs, persistent emergents, emergent mosses or lichens with greater than 30% aerial coverage, total area exceeds 8 ha (20 acres). Or area less than 8 hectares if the boundary is active wave-formed or bedrock or if water depth in the deepest part of the basin exceeds 2 m (6.6 ft) at low water. Lacustrine waters may be tidal or non-tidal, but ocean-derived salinity is always less than 0.05%.
Lagoon
The expanse of water separating an offshore bar from the shore.
Landscape
An area made up of a distinct association of forms, both physical and cultural or an area characterized by a certain type of scenery.
Leaching
The process of nutrients being washed down through the soil into the groundwater.
Levee
A long, narrow, earthen embankment usually built to protect land from flooding. Levees confine streamflow within a specified area to prevent flooding.
Life support system
Is an ecological process which sustains and supports the productive-adaptive- and renewable capacities of land, water, air and/or the whole biosphere.
Mangrove
Mangroves are marine, or estuarine swamps. They may be found on coral reefs or protected shores. These areas are of immense importance worldwide covering between 60 - 70% of all tropical coasts. The trees and shrubs of these forests collectively known as "mangroves" are a taxonomically diverse lot which includes some ninety species in some ten families. Despite their diversity, these species share many important physiological and morphological adaptations: Mangroves are all broad-leaved, deciduous trees and shrubs and are "obligate halophytes" (a term meaning that they can only grow in salty soils). All are extremely tolerant of saturated conditions some may be flooded up to their crowns during high tide (Brewer, 1988). Root morphology and reproductive strategies are remarkably similar even in taxonomically remote species. Most species have roots, which protrude above the surface of the water. Some of these have "pneumataphores" which enable them to take in oxygen during low tide and salt excluding membranes, which enable them to utilise seawater without undue salt build-up. A surprising number of woody mangroves have developed "viviparous" reproductive strategies meaning that by the time a seed has fallen to the ground it has already begun to germinate. Presumably this adaptation circumvents the problems associated with germination under the anoxic, haline condition of the mangrove environment.
Marine
Marine wetlands are nourished only by ocean water and the minerals and nutrients contained therein. Typical examples of marine wetlands include reefs, ocean beaches, and marine aquatic beds. Salinities exceed 30 parts per thousand.
Marsh (see also Freshwater marshes)
Wetlands characterised by frequent or continual inundation, emergent herbaceous vegetation such as cattails and rushes, and mineral soil.
Mature soil
A soil with well-developed characteristics produced by the natural processes of soil formation, e.g. having clearly developed genetic horizons, and in equilibrium with its environment. A manure profile is one which has attained full development.
Maximum sustainable yield
The greatest amount of resources (biomass, individuals etc.) which can be harvested or taken from the environment within a certain period and be replaced by the population growth. MSY often occurs when the population size is at half (1/2) of the carrying capacity level.
Meander
A more or less regular curve of a river or valley.
Meandering
Winding or bending in river beds, usually erosion occurs on the outer bend, while sediment is deposited on the inner bend. This can lead to the meander being cut of and the river changing its channel.
Metabolism
The totally of the synthesis and degradative biochemical processes of living organisms.
Microclimate
The climate of a very small or confined area, influenced by local conditions.
Minimal viable population
MVP for any given species in any given habitat is the smallest isolated population having a 99% chance of remaining extant over the next 1000 years despite the natural (demographic, genetic and environmental) stochastic and natural catastrophes. Sometimes also taken for 95% chance over 100 years.
Minimum dynamic area
The area of suitable habitat necessary for maintaining the minimum viable population.
Mire
An ecosystem in which the vegetation is rooted in a wet peat, a collective term for various bogs and fens.
Monocotyledonous plants
A class of Angiospermae named from the fact that the germinating seed produces a single cotyledon. They are also distinguished by the fact that vascular bundles are scattered throughout the stem but not arranged in a cylinder. The leaves are very commonly parallel veined and the flower parts have triradial symmetry. They include familiar bulbs such as daffodils, snowdrops, lilies, etc., and the cereals and grasses such as maize, wheat, rice, etc.
Monoculture
Cultivation of the same crop in the same area year after year.
Mutation
A heritable change in a genetic character resulting either from a change in the gene at a locus, or alterations in chromosomal structure.
Natural ecosystem
An ecosystem where since the industrial revolution (about 1750) human impact has been no greater than that of any other native species, and has not affected the ecosystems structure.
Natural resource (see also Resource)
Natural resources are all those objects and processes in the natural environment which have some benefit or use to man. The term natural resource is rather vague At one time it referred to the things, or sources of energy, in the environment used by humanity coal, iron, timber, rivers for hydropower, and the like. As our knowledge of the environment and our use of the planet expanded, virtually everything on earth along with the sunlight impinging on it has come to be considered as a natural resource. Some resources, such as the Antarctic ice cap, are only potential resources, since we are not using them. For distinction between renewable and non renewable resources, see resources.
Nature/natural environment
The term nature is used for all those processes and components in our environment which are spontaneously formed and not, or minimally, influenced by man. The natural world consists of both biotic (living) and abiotic (non living) components and all the interactions between these components. Since mankind has become the dominating factor on the Earth, it tends to see itself as separated from the natural order, which is reflected by the increased use of term natural environment, to emphasise that the remaining natural processes and components are only one aspect of mans total environment (see also under environment). The term natureis usually used when referring to the living part of the biosphere while environmentis usually associated with the abiotic aspects (e.g. the quality of air, water and soil).
Net primary productivity (see also Primary production)
The total production of organic matter by an autotrophic individual or population per unit time per unit area or volume, less that consumed by the catabolic process of respiration.
Non Governmental Organisation (NGO)
Any organisation that is not a part of federal, provincial, territorial or municipal government. Unless otherwise indicated, NGOs include private voluntary organisations, corporations, educational institutions, and labour unions.
Niche
Constitute a unique set of resources a species utilises within a biological community.
Nutrient
The inorganic compounds which are essential for plant growth (macro nutrients: nitrogen- compounds, phosphorus-compounds and silicon-compounds, micro nutrients: metal-ions).
Nutrient balance
The flow of nutrients through and within the system, including the nutrient cycle = the transfer of nutrients within and between the ecosystem parts. The nutrient losses and gains = the amount of nutrients by inputs and outputs of the system, accumulating in or leaving the ecosystem or ecosystem parts.
Nutrient loading
The amount of nutrients available over a certain time period.
Ocean Beaches
The oceans shores are among the more hostile environment for most life-forms. Anything that is to survive in this environment must be able to deal with the stresses of two incredibly different worlds - the ocean and the land. At one moment a patch of sand may be dry and scorching hot and then cool and drenched with saline ocean water the next. Within the span of a single day, the water in a tidal pool may change from essentially freshwater after an early morning rain, to salinities approximating ocean water after high tide, and then to a hyper-saline condition after exposure to the mid-day sun. Despite these problems, life does manage to hold on and even thrive - both on rocky shores and unconsolidated shores.
Offshore
A sea zone of a beach, located in sea.
Ombrogenous
Wet habitats arising from precipitation rather than from water in the ground.
Ombrotrophic
Literally fed by rain. The term applies to areas such as bogs that are entirely depend on rain for their nutrient supply.
Omnivorous
Eating all kinds of food.
Organic matter (see also Biomass)
Matter containing carbon in its molecule (e.g. carbohydrates or glucose, the main constituent of living organisms.
Organism
A living being or form of life that is a cell or is composed of cells. Any member of the kingdoms of Prokaryotae (bacteria), Protista, Fungi, Animalia, or Plantae.
Over-exploitation
The use or extraction of a resource to the point of depletion (or extinction). Biologically. it usually refers to over-harvesting of a resource population to a level below the maximum needed for a sustainable yield (= the level at which a population can, theoretically, continue to be optimally harvested over the long run).
Over-grazing
Grazing which exceeds the recovery capacity of the community and thus reduces the available forage crop or causes undesirable changes in the community composition.
Oxbow Lakes
Oxbow lakes are lakes or ponds found in association with river channels. When a river channel becomes obstructed by silt and debris, the river will often cut a new channel around the obstruction. With time the obstructed area may become completely cut off from the river and begin developing as a lake. Over time an oxbow lake may become filled with organic material and be transformed into a marsh.
Oxidation
Release of electrons or hydrogen ions. This reaction releases energy.
Palustrine
"Palustrine" comes from the Latin word "palus" or marsh. Wetlands within this category include inland marshes and swamps as well as bogs, fens, tundra and floodplains. Palustrine systems include any inland wetland, which lacks flowing water and contains ocean derived salts in concentrations of less than 0.05%. According to the U.S. Fish and Wildlife Services definition, Palustrines are all nontidal wetlands dominated by trees, shrubs, persistent emergents, emergent mosses, or lichens, and all such tidal wetlands where ocean-derived salinities are below 0.5 ppt. This category also includes wetlands lacking such vegetation but with all of the following characteristics, (1) area less than 8 ha (2) lacking an active wave-formed or bedrock boundary (3) water depth in the deepest part of the basin less than 2 m (6.6 ft) at low water (4) ocean-derived salinities less than 0.5 parts per thousand. A Palustrine system can exist directly adjacent to or within the Lacustrine, Riverine, or Estuarine systems.
PCBs (Polychlorinated biphenyls)
A class of chemicals used as electrical insulators. PCBs persist in the environment and accumulate through the food chain.
Peats
Peats are extremely light organic soils, which develop under conditions in which there is a net accumulation of organic matter over time. They are formed where the natural cycle of plant production and decomposition is disrupted under waterlogged conditions. Peats have many uses. Dry weight is primarily reliant on the degree of decomposition. Peats, which develop under extremely acidic, anoxic conditions, are usually the lightest. When this type of soil is broken apart plant parts and at times whole plants are easily distinguished. The heaviest peats are found in areas where decay occurs more rapidly. These soils are fine and powdery when dried and plant parts are virtually never distinguishable.
Peatlands
Genetic term used to refer to all peat-accumulated wetlands (bogs and fens).
Phenotype
The sum total of observable structural and functional properties of an organism. The visible or otherwise measurable physical and biochemical characteristics of an organism, the product (result) of the interaction between the genotype and the environment. A group of individuals exhibiting the same phenotypic characters.
Permeability
A hydrogeological factor describing the ability of a geological unit to conduct groundwater flow. The ability of a material to transmit water though its pores when subjected to pressure.
Pest
A pestmay be defined as an uncontrolled increase in numbers of one species in an otherwise balanced ecosystem. Oldfield (1984) defines pest as an organism that competes with, preys upon, parasites, or otherwise interferes with man or his domesticated (cultivated or husbanded) biota.
pH
A measure of acidity of water, in which pH 7 is neutral, values above 7 are alkaline and values below 7 acid. The ocean has pH of about 8, an alkaline lake might be pH 10, and an acid bog pH 3.5.
Phagotrophic organisms
Organisms, which are able to consume or absorb bacteria.
Pheromones
Volatile secretions, which control the behaviour of insects and other organisms.
Photosynthesis
The complex process carried out by plants and some bacteria in which light energy absorbed by the pigment chlorophyll is used to convert a carbon dioxide into sugar (carbohydrates), oxygen is released.
Piscivorous
Fish-eating.
Plankton
Small organisms suspended in water column. They are unable to maintain their position or distribution independent of the movement of water or air masses. The plants are called phytoplankton, the animals - zooplankton.
Pleistocene
The last ice age from 1.5 million to c.10 000 years ago.
Pluvial
In hydrology, anything that is brought about directly by precipitation.
Pocosin
The term "pocosin" comes from the Algonquin phrase "swamp on a hill". As its name suggests, these swamps are usually located in upland areas. They are evergreen shrub bogs. Although these areas are typically dominated by woody vegetation, they bare much in common with bogs. Since they are located in upland areas where rain is normally the only significant water source, soils are likely to be low in minerals and nutrients. However, unlike most uplands, drainage is poor and, consequently, the soil is usually saturated and acidic. As is typical of a bog environment, decomposition occurs slowly and a fibrous type of peat tends to accumulate over time. The vegetation most commonly found in these habitats are broad-leaved, deciduous shrubs such as holly, bayberries and sweet cyrilla.
Podsol
Soil with acid-humus horizon overlying B-horizon of iron-oxide or iron-oxide and humus accumulation.
Pond
A small (according to Russian terminology, not more than 1 sq km) natural or artificial body of standing fresh water usually with negligible current and having more or less continuous vegetation from the marginal land areas into the water, in the absence of significant wave action.
Prairie Potholes
Much of the north central United States and the south central portions of Canada are covered by literally millions of acres of small, waterlogged depressions called potholes. Most pothole wetlands were formed 10,000 years ago during the last ice age. As the glaciers melted, thousands of depressions left in the ground were filled with water. Despite their modest appearance, these depressions provide critical resting, feeding and nesting habitat for migratory waterfowl. Much of the prairie pothole region is highly suited for agriculture, as a consequence many (in some places up to 95%) potholes have been drained. This poses a serious threat not only to the prairie potholes themselves, but also to the duck population, which depends on them. Solutions to these problems range from protecting existing potholes, to creating artificial potholes. In many places conscientious farmers have opted to plough around existing potholes leaving attractive patterns on the landscape. In some areas blasting can be used to reclaim small wetlands. Blasting is particularly effective in bogs and marshes where succession has advanced to the point that vegetation encroaches on open water thereby reducing the carrying capacity of the site for waterfowl and other wildlife.
Preservation
Keeping something in its present state.
Primary production
Green plants and certain bacteria are able to convert inorganic matter into biomass using energy from solar radiation or chemical energy. They are the first link in the food chain and are therefore called the primary producers (autotrophs). All other life depends on the energy fixed by these primary producers. The process of assimilation and fixation of inorganic carbon and other inorganic nutrients into organic matter by autotrophs is called primary production. In calculations of the primary production of an ecosystem the chemical energy source is usually left away. The total amount of energy fixed in living organisms is called the Gross Primary Production (GPP). Through metabolic activities of the plants themselves and by heat loss, 50% or more to the Net Primary Production reduces the GPP.
Productivity
The rate of organic matter production per unit area per unit time by an ecosystem, and which can be used to compare natural ecosystems with those affected by human activity and, indeed, with totally human-made ecosystems.
Protected area
An area dedicated primarily to protection and enjoyment of natural or cultural heritage, to maintenance of biodiversity and/or to maintenance of life support systems.
Protection
Securing something for a particular purpose.
Ramsar
City in Iran, on the shore of the Caspian Sea, where the Convention on Wetlands was signed on 2 February 1971, thus the Conventions nickname is Ramsar Convention on Wetlands.
Ramsar Criteria
Criteria for Identifying Wetlands of International Importance, used by Contracting Parties and advisory bodies to identify wetlands as qualifying for the Ramsar List on the basis of representativeness or uniqueness or of biodiversity values.
Ramsar Management Guidelines
Guidelines on Management Planning for Ramsar sites and other wetlands.
Ramsar List
The List of Wetlands of International Importance.
Ramsar sites
Wetlands designated by the Contracting Parties for inclusion in the List of Wetlands International Importance because they meet one or more of the Ramsar Criteria.
Realignment
Type of channelization in which the stream channel is shortened via an artificial cut-off.
Reallocation
Disregarding the (original) indigenous ecosystem, its species and functional relationships, imposing new uses and outputs on the area, mostly by introducing new species, management measures and imposing ongoing inputs of energy and materials on the system.
Recharge
To add water to an aquifer. Also, the water added to an aquifer.
Reclamation
An alteration in an ecosystem that creates another type of ecosystem of value to humans.
Recreation
The genetic term for leisure-time activities. Recreations are frequently indulged in away from home.
Reefs
Reefs are ridges or mound formed through the growth and accumulation of sedentary invertebrates. They may be classified as either wetland or deepwater habitats and will periodically give rise to lush aquatic beds and occasionally mangrove forests. For the most part reefs are restricted to waters at tropical and subtropical latitudes - consequently nearly all U.S. wetlands are limited to the waters around the Hawaiian Islands and the Florida coast.
Regeneration
Re-growth, restocking and re-development after disturbance or deviations of the naturalor mean conditions of populations, communities, ecosystems and or landscapes (meta communities).
Rehabilitation (see also Restoration)
Human activity aiming at repairing damaged or blocked ecosystem functions with primary goal of raising ecosystem productivity, aiming at a self sustaining ecosystem.
Relict species
Persistent remnants of formerly widespread fauna or flora existing in certain isolated areas or habitats
Reproduction
Increase of number of individuals of a species population by sexual propagation or fission/ division of cells.
Reptile
A type of animal, such a snake or lizard, whose blood changes according to the temperature around it, and that usually lays eggs.
Resident Fish
Fish species that reside in freshwater throughout their lives (also called riverine fish).
Resilience
The ability of the ecosystem to recover back to its normal range of the oscillating equilibrium after a heavy shock or catastrophic event.
Resin
Adhesive inflammable substance insoluble in water secreted by most plants and exuding naturally or upon incision, for example from fir and pine. A synthetic resin is a solid or liquid organic compound made by polymerisation or other process and used especially as, or in plastics.
Resistance
The ability of the ecosystem to return back to the equilibrium (mean value) after shocks and deviations which can bring the system out of balance, or the capacity to buffer and adsorb these shocks without major impacts.
Resource
The term resource relates to any means of supplying what is needed and usually refers to a stock that can be drawn on. Resources are used to maintain the human metabolism (e.g. water and food), to provide shelter or satisfy other material needs (e.g. wood, metals, stone, energy, etc.), or to satisfy recreational and aesthetic needs (e.g. water for swimming, the scenic value of the landscape). To determine the (sustainable) use level, it is important to make a distinction between renewable and non-renewable resources. Renewable resources can be regenerated at a constant level, either because it recycles quite rapidly (water), or because it is alive and has the capacity for reproduction and growth (organisms and ecosystems). As long as the rate of use is less than their rate of regeneration, and as long as their environments are kept suitable, they will go on replacing themselves. Non-renewable resources are not regenerated or reformed in nature at rates equivalent to the rate at which we use them (such as oil). A special category of non-renewable resources are resources which are not lost or worn out by the way we use them, and can be reprocessed (recycled) to be used again and again (such as many metals). A special category of resources are inexhaustible resources such as sunlight. Also those resources for which our foreseeable rate of use is relatively minute in relation to the supply (such as table salt from the oceans) could be mentioned here.
Respiration
The respiration activity of living organisms oxidises organic matter (carbohydrates) back to CO2 and H2O (i.e. the reverse of photosynthesis). The process by which the energy of organic material is available to drive energy-consuming processes in the cell, such as the formation of cell walls, proteins, or cell movement. There are three types of respiration, which roughly parallel the various types of photosynthesis: (1) Aerobic respiration - gaseous (molecular) oxygen is the hydrogen acceptor (oxidant), (2) Anaerobic respiration - gaseous oxygen not involved. An inorganic compound other than oxygen is the electron acceptor (oxidant). (3) Fermentation - also anaerobic but an organic compound is the electronic acceptor (oxidant).
Restoration
To return a degraded system or population to its original condition. Wetland restoration - the reestablishment of a disturbed or altered wetland as one with greater function or acreage. This may involve re-establishing original vegetation, hydrology, or other parameters to re-establish original or closer-to-original wetland functions.
Riparian
Pertaining to a river (e.g., the riparian zone). Riparian ecosystem (see also riparian zone) Ecosystem that has a high water table because of its proximity to an aquatic or to subsurface water. Usually occurs as an ecotone between aquatic and upland ecosystems, but with distinctive vegetation and soils.
Riparian Forested Wetlands
Riparian forested wetlands are dominated by surface water. They are linear systems found along lakes, streams, and rivers from headwaters down to the sea. Riparian forested wetlands are saturated or inundated with water during the winter, when evapo-transpiration is low, because plants are dormant and precipitation is high and during the early part of the growing season, when precipitation and runoff are still abundant. These wetlands are generally not wet in the summer or fall except during flood conditions. Riparian wetlands do not have particular characteristics of pH or nutrient load, but differ based on inputs, substrate, and vegetation type. However, riparian wetlands are particularly productive ecosystems, receiving large inputs of water and nutrients from upstream sources during flooding. This feature has led to their conversion for agricultural use, a practice that has contributed to water quality degradation. In the United States southern deepwater swamps are riparian systems notable for the standing water present during much of the year. While they may be traversed by rivers or streams, which provide seasonal water inputs, these systems may also be headwaters. A cypress dome is an anomalous southern deepwater swamp type that is typically precipitation versus surface water, dominated. Cypress domes typically exist as isolated depressions in very gently sloping landscapes. Other examples of riparian forested wetlands include maple swamps, bottomland hardwood forests, and cottonwood riparian areas.
Riparian Zone
The habitat found on stream banks and river banks, where semi-aquatic and terrestrial organisms mingle.
River Banks and Sandbars
River banks are constantly changing. In some places, moving water causes banks to erode and trees to fall. In other places, sand will accumulate forming bars, or even forested islands. Sometimes, if a channel becomes sufficiently blocked by debris a river may change its course altogether, leaving an oxbow lake where its old bed once was. One of the fascinating aspects of sandbars is the way that they illustrate succession. Sand bars on a typical midwestern river are likely to be colonised by dense growths of water-willow - a small herbaceous plant (no relation to willow-trees) that bears thin, willow-like leaves. Real willows can often be seen taking root just a little further up on the bar. Since willows reproduce vegetatively their root systems form net-like structures, which capture bits of debris and sediments. Provided that the river does not change its course too dramatically these sediments will eventually accumulate to the point that grasses will develop and sycamore and cottonwood seeds will begin to germinate. Eventually this piece of land may develop into part of a hardwood dominated floodplain.
Riverine
The term "riverine" is related to the word "river" and refers to any habitat fed by water flowing through a channel. Riverine wetland habitat includes river banks, streams, freshwater marshes, and freshwater aquatic beds. All wetlands and deepwater habitats contained within a channel except those wetlands (1) dominated by trees, shrubs, persistent emergents, emergent mosses, or lichens, and (2) which have habitats with ocean-derived salinities in excess of 0.5 parts per thousand.
Rocky Shores
Among the more successful organisms on a rocky ocean shore are the barnacles and mussels, which are able to hold firmly to rocky substrate and feed off of the plankton and detritus that is washed in by the waves. Protected rocky shores may contain many types of algae, which are eaten by limpets and periwinkles. The dominant predators in these strange habitats are birds and the harmless looking oyster drills.
Run-off
Overland flow of water following rain or irrigation events.
Salinity
The content of salts in soil or water, in sufficient quantity, these can be detrimental to plants and animals.
Salt Marshes
Salt marshes are tidally influenced estuarine systems with emergent vegetation. They may receive inflow of fresh water from rivers, runoff, or ground water. They frequently form on the leeward side of barrier beaches directly across from exposed ocean shore, or in river deltas directly downstream from brackish tidal marshes. Freshwater inflow is important in diluting the salinity of the system. Salinity is the major stressor in this wetland system and limits species to those that have evolved adaptive mechanisms. Readily available nutrients and organic matter from upstream sources and runoff, and the alternating aerobic and anaerobic conditions caused by the tides result in the very significant productivity of salt marsh ecosystems. Salt marshes have the highest primary productivity of all wetland systems and have higher primary productivity than most upland systems. Although salt marshes are extremely productive communities, they are not very diverse. The inner marsh zone, which is flooded most of the time, is composed almost entirely of grasses in the genus Spartina (cordgrass). Diversity within the salt marsh community tends to increase with distance from the ocean. First, clusters of tiny halophytes, such as salt-wart and sea lavender, appear amid the Spartina. Eventually the Spartina will be replaced by reeds, sedges and goldenrod - as well as other species commonly associated with brackish or freshwater marshes.
Secchi disk technique
A method for estimating the transparency of water by submerging a white disc of standard size (Secchi disk) and recording the depth at which it disappears from view.
Sediment
Particles of material that are transported and deposited by water, wind or ice.
Sediment control
Sedimentation is important to the existence of wetlands, serving to stabilise them and counteract erosion along the shoreline. Sediment trapping is the process by which particles of any size are retained and deposited within the wetland. As the plant life of a wetland increases, flow velocity is reduced and sediment settles out as the slower-running water carries less suspended material. Sediment is often the main pollutant in the river systems. Since wetlands commonly occupy basins, they may function as pools where sediment can settle. The vegetation, such as reeds, slows down a rivers flow and the reduction in the velocity can cause the water to deposit some of its load.
Shadow price
Price adjusted to eliminate any distortions caused by policies or market imperfections so as to reflect true willingness to pay.
Silt
Fine sediment composed of particles between 0.004 mm and 0.06 mm in diameter and deposed by water in channels, harbour, lakes, delta etc.
Siltation
The filling up of a wetlands with water-borne sediment.
Slough
A swamp or swamp like region, a marshy or reedy pool, pond, inlet, backwater or the like.
Soligenous
Wet habitats that are supplied by groundwater rather than by precipitation, e.g. fens.
Species
A population whose members are able to interbreed freely under natural conditions.
Spermatophytae
In some classifications a major division of plants containing all seed-bearing plants.
Stratification
Organisation into horizontal strata, the vertical structuring of a community or a habitat into superimposed horizontal layers.
Substrate
The base or material on which an organism lives, subsoil.
Subtidal
The area, which is located below a tideland.
Succession
The gradual process of change in species composition, community structure and physical characteristics that occurs naturally (ecosystem dynamics) or by human caused disturbance to a biological community (reset and repair). Biotic succession is defined by Dasmann (1976) as the sequence of biotic communities which tend to succeed and replace one another in a given area over a period of time. Each community in the sequence changes | |
Glossary
