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Glossary of Conservation Terms

trillium in a Michigan forest

Click a letter in the alphabet to view conservation terms beginning with that letter. Definitions apply to usage within Great Lakes Inform but may also be applied to conservation knowledge and understanding more broadly, unless otherwise stated. 

For a guide to the advanced search terms that you can use when looking for resources related to specific conservation categories, check out the Great Lakes Inform Taxonomy Guide.

AB | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z



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Adaptive management—Adaptive management is an ongoing process of planning, doing, assessing, learning, and adapting by applying what was learned to the next iteration of a management process. See the “Collaborative Adaptive Management” article for a diagram and more information.1


Allochthonous material—Organic material that falls into a stream from the surrounding land, including leaves, branches and even entire trees.2 Fine organic particulate matter and dissolved organic matter delivered by surface runoff is also allochthonous material. Many streams, especially streams located in the headwaters of a drainage system, derive most energy for aquatic life from allocthonous material.3 Compare to autochthonous material.


Aquaculture—The farming of aquatic organisms including fish, mollusks, crustaceans, and aquatic plants with some sort of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated.4


Aquatic—(1) Consisting of, relating to, or being in water; living or growing in, on, or near the water. (2) Taking place in or on the water. (3) An organism that lives in, on, or near the water.5 Aquatic ecosystems can be either freshwater or marine. Freshwater aquatic ecosystems include lakes, ponds, rivers and wetlands.6


Aquifer—(1) A geologic formation, a group of formations, or a part of a formation that is water bearing.  (2) A geological formation or structure that stores or transmits water, or both, such as to wells and springs.7 Aquifers can be composed of various geologic materials, including porous rock, sand or gravel, that are capable of containing and transmitting water.  Typically, water enters an aquifer via precipitation, which infiltrates permeable land surfaces into the saturated zone, where the water then moves through the aquifer at a rate dependent on the permeability and porosity of the aquifer material. Confined aquifers are contained within two underground layers of impermeable rock and often are characterized by pressurized flow when a well is drilled.8 Use of the term “aquifer” is usually restricted to those water-bearing structures capable of yielding water in sufficient quantity to constitute a usable supply.


Atrazine—Atrazine (C8H14ClN5) is a white, crystalline solid that is used as a synthetic herbicide to kill broadleaf weeds in agricultural and roadway applications. Atrazine is one type of triazine herbicide, a chemical group that also includes simazine and cyanazine. Atrazine is the most commonly used herbicide in the United States, with application of approximately 76 million pounds active ingredient in 1997. Atrazine is a Restricted Use Pesticide (RUP), which means that only registered professionals can apply atrazine, and it is not available to the general public.9


Autochthonous material—(1) Substances, materials or organisms originating within a stream or waterway. (2) Organic material produced in a stream usually through primary production.10 Autochthonous material is generally found in greater abundance downstream of a river’s headwaters, where riparian vegetation decreases in abundance and relative importance to energy supply.11 Where the stream channel widens, more sunlight is available, and instream plants and algae become the primary sources of energy in the aquatic community. Compare to allochthonous material.12


Available nutrients—Nutrient ions or compounds in forms that plants can absorb and use for growth.13 The three primary nutrients that all plants need to grow include nitrogen, phosphorus and potassium. Most nutrients are made available to plants by organic material in soils. However, before plants can use this material to grow, microorganisms and chemical reactions in the soil must first transform the organic matter into inorganic ions that plants can absorb.14



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Base flow—(1) The flow that a perennially flowing stream (one that flows continuously year round except for in periods of drought) reduces to during the dry season.  Base flow is supported by groundwater seepage into the channel.  (2) The fair-weather or sustained flow of stream discharge not attributable to direct runoff from precipitation, snowmelt, or a spring.  Discharge entering stream channels as effluent from the groundwater reservoir.  Base flow is characterized by flow regime (frequency, magnitude, and duration daily, seasonally, and yearly), minimum low flow events and in context of the size and complexity of the stream and its channel.15

Basin—A group of interconnected drainages.16

Bog—Bogs are poorly drained freshwater wetlands that are characterized by a build-up of peat.  Sphagnum mosses are also frequently found in many bogs.17 Bogs depend primarily on precipitation for their water source and are usually acidic and rich in plant residue with a conspicuous mat of living green moss.  Only a restricted group of plants, mostly mycorrhizal (fungi, heaths, orchids, and saprophytes), can tolerate bog conditions. Vegetation such as black spruce, blueberries, cranberries, orchids and insect-eating plants are typical in Great Lakes bogs.18  Also referred to as peat bog.


Biota—The plant and animal life of a region or ecosystem.19


Biodiversity—The variety of living organisms, usually measured as the number of different species in an area, and the number of individuals of each species. The more species there are, and the more similar in population size they are, the higher the biodiversity. However, the term “biodiversity” is often meant to include variability in a broader sense, including the genetic and ecosystem levels.20


Biofuel—Fuel produced from renewable biomass material, commonly used as an alternative, cleaner fuel source.21



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Catch per unit effort (CPUE)—The amount of biomass (e.g. fish, mollusks, crustaceans) that is harvested divided by the amount of harvesting effort used to get it. Effort is measured in any appropriate unit (e.g. fishing days). Changes in CPUE are often used as an indirect measure of changes in population size.22


Climate—The collective meteorological elements that characterize the average and extreme conditions of the atmosphere over a long period of time for a given area or region of the Earth. The collective state of the atmosphere at a given place or over a given area within a specified period of time. There are two basic types of climate. Continental climates are characteristic of land areas separated from the moderating influences of oceans by distance, direction or mountain barriers and are marked by relatively large daily and seasonal fluctuations in temperature. Oceanic climates are characteristic of land near oceans which contribute to the humidity and at the same time have a moderating influence on temperature and the range of temperature variation.23


Climate change—(1) Generally, climate change encompasses all forms of climatic variation (e.g., statistical variation in temperature or precipitation) calculated for different periods but relating to the same area) regardless of their statistical nature or physical causes. Climate change may result from changes in solar activity, long-period changes in the Earth's orbital elements (eccentricity, obliquity of the ecliptic, precession of equinoxes), natural internal processes of the climate system, or anthropogenic forcing (e.g., increasing atmospheric concentrations of carbon dioxide and other greenhouse gases). (2) The term "climate change" is often used in a more restricted sense, to denote a significant change in the mean values of a meteorological elements over time, where the means are taken over periods of decades or longer and where the meteorological changes have important economic, environmental and social effects.24


Collaboration—Collaboration means “to work together.” It is a mutually beneficial relationship between two or more parties to achieve common goals by sharing responsibility, authority, and accountability for achieving results. It is more than simply sharing knowledge and information (communication) and more than a relationship that helps each party achieve its own goals (cooperation and coordination). The purpose of collaboration is to create a shared vision and joint strategies to address concerns that go beyond the purview of any particular party.25


Collaborative Adaptive Management—Collaborative adaptive management is the flexible decision-making process of adaptive management combined with the concept of collaboration. See Collaboration in the glossary above for additional details. See the “Collaborative Adaptive Management” article for a diagram and more information.


Community—In ecology, a community is a naturally occurring, distinctive group of different organisms which inhabit a common environment, interact with each other, and are relatively independent of other groups.26 For example, sedge meadow communities grow in open areas of saturated soil and transition areas between aquatic habitat and uplands, and these communities are characterized by sedges, spikerushes, bulrushes, grasses and perennial flowers.27


Condition—In ecology, condition is a measure of the biological composition, structure and biotic interactions that characterize an ecosystem.28


Conceptual model—Conceptual models are simple box and arrow diagrams used to represent relationships among key variables within the scope of a particular problem.  Natural resource professionals often use conceptual models as a first step in framing a particular conservation problem as well as proposed solutions, because models help identify likely sources of the problem as well as realistic conservation strategies for addressing the problem.


Connectivity (of riverine ecosystems)

Connectivity provides for the movement of energy and materials, such as organisms, from one habitat type to another and creates a physical linkage between habitats through a natural conduit.  Materials transferred through conduits can be abiotic (e.g., water, sediment and nutrients) or biotic (e.g., organisms, species, or groups of species). Connectivity can be described for different ecosystem types, including aquatic and terrestrial habitats. There are at least six types of connectivity in an aquatic system:

[1] Lateral flood pulse connectivity—The hydrologic connectivity a river has with its floodplain during a flood event or over bankfull conditions.  A conduit that provides for the movement of energy, water or nutrients and biotic matter between a river and its floodplain.

[2] Lateral non-flood pulse – The connectivity of the main channel of a river to its backwaters.

[3a] Longitudinal connectivity (aquatic) – The interaction between river reaches either upstream or downstream.

[3b] Longitudinal connectivity (aerial, straight line distance) – The distance between wetland and terrestrial feeding, nesting and resting habitats

[4] Main stem to tributary connectivity – The connection between a main stem river and its tributaries.

[5] Subsurface connectivity (below ground) – Hydrologic connection of shallow ground water among channel and lateral habitats, with movement of water and solutes as a result of differences in hydraulic head (difference in elevation between intake and discharge points for a liquid).29


Conservation—Broadly, preventing the loss of biodiversity and biological processes. This loss is generally human-induced. Conservation is distinct from preservation because it involves recognizing the dynamic nature of biological systems, and allowing them to change and evolve.30


Conservation target—A limited suite of species, communities and ecological systems that are chosen to represent and encompass the full array of biodiversity found in a project area. They are the basis for setting goals, carrying out conservation actions, and measuring conservation effectiveness. In theory, conservation of the focal targets will ensure the conservation of all native biodiversity within functional landscapes. Often referred to as “focal targets,” “biodiversity features” or “focal biodiversity.”31


Current status—An assessment of the current “health” of a conservation target as expressed through the most recent measurement or rating of an ecological or biological indicator of the target.32



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A structure of earth, rock or concrete designed to form a basin and hold water back to make a pond, lake or reservoir.  A barrier built, usually across a watercourse, for impounding or diverting the flow of water.  General types of dams include:


[1] Arch dam – Curved masonry or concrete dam, convex in shape upstream, that depends on arch action for its stability; the load or water pressure is transferred by the arch to the abutments (supporting side walls of the river valley).


[2] Buttress dam – A dam consisting of a watertight upstream face supported at intervals on the downstream side by a series of buttresses.


[3] Cofferdam – A temporary watertight enclosure that is pumped dry to expose the bottom of a body of water so that construction, as of piers, a dam, and bridge footings, may be undertaken.  A “diversion cofferdam” prevents all downstream flow by diverting the flow of a river into a pipe, channel or tunnel.


[4] Crib dam – A barrier or form of gravity dam constructed of timber forming bays, boxes, cribs, crossed timbers, gabions or cells that are filled with earth, stone or heavy material.


[5] Embankment dam – A dam constructed of fill material, usually earth or rock, placed with sloping sides and usually with a length greater than its height.  Types of embankment dams include: earthfill or earth dam – a dam in which more than 50 percent of the total volume is formed of compacted fine-grained material obtained from a borrow area (i.e., excavation pit); fill dam – any dam constructed of excavated natural materials or of industrial waste materials; homogeneous earthfill dam – a dam constructed of similar earth material throughout, except for the possible inclusion of internal drains or drainage blankets; distinguished from a zoned earthfill dam;  hydraulic fill dam – a dam constructed of materials, often dredged, that are conveyed and placed by suspension in flowing water; rockfill dam – a dam in which more than 50 percent of the total volume is comprised of compacted or dumped pervious natural or crushed rock; rolled fill dam – a dam of earth or rock in which the material is placed in layers and compacted by using rollers or rolling equipment; and  zoned embankment dam – a dam which is composed of zones of selected materials having different degrees of porosity, permeability and density.


[6] Gravity dam – A dam constructed of concrete or masonry that relies on its weight for stability.


[7] Inflatable dam – A dam constructed of heavy-duty rubber or similar material and inflated with air or water and used for small-scale impoundment of flood flows or as flashboards for regulating the overflow of larger dams.


[8] Masonry dam – A dam constructed mainly of stone, brick, or concrete blocks that may or may not be joined with mortar.  A dam having only a masonry facing should not be referred to as a masonry dam.


[9] Weir – A dam in a river to stop and raise the water, for the purpose of conducting it to a mill, forming a fishpond or the like.  When uncontrolled, the weir is termed a fixed-crest weir.  Other types of weirs include broad-crested, sharp-crested, drowned, and submerged.33


Delta—A low, nearly flat accumulation of sediment deposited at the mouth of a river or stream, commonly triangular or fan-shaped.34 The Lake St. Clair delta is the largest freshwater delta in the world.35


Density dependence—The way in which the growth rate of a population depends on the size of that population. Generally, the population growth rate slows down as carrying capacity (the maximum number of individuals an area’s resources can sustain indefinitely without depleting those resources) is approached (positive density dependence or compensation).36


Desired conditions—A measurement or rating of an ecological indicator that describes the level of viability/integrity intended for a conservation project. Equivalent to a project goal.37


Diadromous—A category of fish that migrate between marine and freshwater environments.38


Dike—(1) (Engineering) An embankment to confine or control water, especially one built along the banks of a river to prevent overflow of lowlands; a levee.  (2) (groin, spur, jetty, deflector, boom) A structure designed to: (a) reduce water velocity as stream flow passes through the dike so that sediment deposition occurs instead of erosion (permeable dike), or (b) deflect erosive currents away from the stream bank (impermeable dike).39


Dissolved Oxygen (DO)—(1) Concentration of oxygen dissolved in water and readily available to fish and other aquatic organisms. (2) The amount of free (not chemically bound) oxygen dissolved in water, wastewater, or other liquid, usually expressed in milligrams per liter, parts per million, or percent of saturation. The content of water in equilibrium with air is a function of atmospheric pressure, temperature, and dissolved-solids concentration of the water. The ability of water to retain oxygen decreases with increasing temperature or dissolved solids, with small temperature changes having the more significant offset. Photosynthesis and respiration may cause diurnal variations in dissolved-oxygen concentration in water from some streams. Adequate concentrations of dissolved oxygen are necessary for the life of fish and other aquatic organisms and the prevention of offensive odors. Dissolved oxygen levels are considered the most important and commonly employed measurement of water quality and indicator of a water body’s ability to support desirable aquatic life. The ideal dissolved oxygen level for fish is between 7 and 9 milligrams per liter (mg/l); most fish cannot survive at levels below 3 mg/l of dissolved oxygen. Secondary and advanced wastewater treatment techniques are generally designed to ensure adequate dissolved oxygen in waste-receiving waters.40


Dissolved-solids concentration (also dissolved mineral content) (1) Minerals and organic matter dissolved in water. (2) The dissolved mineral constituents or chemical compounds in water or solution. Excessive amounts of dissolved solids make water unfit to drink or use in industrial processes.41


Drainage—An interconnected major group of streams entering the marine (or here the lake) habitat.42


Dynamics—In ecology, dynamics refers to the way in which a system behaves or changes over time.43


Dynamic equilibrium—(1) (Surface Water) Within dynamic equilibrium the channel exhibits patterns of erosion and deposition but there is no net change in the input and output of materials. The state is stable but features may change over time. (2) (Groundwater) A condition of which the amount of recharge to an aquifer equals the amount of natural discharge.44



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Ecological communities (also see Communities)Ecological communities are groupings of co-occurring species, including natural vegetation associations and alliances.45


Ecological functions (ecosystem functions)—(1) The processes through which the constituent living and nonliving elements of ecosystems change and interact. The term “ecological function” is often used in reference to the role or specific contribution of an entity to system behavior.  For example, zooplanktons function ecologically to support major aquatic food chains in the Great Lakes. (2) Ecological functions are necessary processes for the self-maintenance of an ecosystem, such as primary production, nutrient cycling, decomposition, etc. The term is used primarily as a distinction from ecosystem values.46


Ecological integrity—Describes ecosystems that are self-sustaining and self-regulating. For example, an ecosystem with high ecological integrity would have complete food webs, a full complement of native species that can maintain their populations and naturally functioning ecological processes (energy flow, nutrient and water cycles, etc.).47


Ecological process—Actions that result from the interacting physical, chemical and biological attributes of ecosystems. Ecological processes include photosynthesis, nutrient and hydrologic cycles, dynamic aspects of food webs, succession, evolution, migration, and the movement of disturbances across a landscape.48

Ecological structure—Physical and biological networks and hierarchies of an ecosystem, such as species richness and evenness, food-web organization, unique habitats such as snags and beaver ponds, varied habitat niches and the structural diversity of soils and landscapes.49


Ecological systems (ecosystems)—Ecological systems are assemblages of ecological communities that occur together on the landscape and share common ecological processes (e.g., flooding), environmental features (e.g., soils and geology) or environmental gradients (e.g., precipitation). Ecological systems can be terrestrial, freshwater, marine or some combination of these. Examples of Great Lakes ecosystems include bottomland hardwood forest, glacial plain streams, and south shore fringing reef.50


Economic valuation—The process of assigning a monetary value to natural resources. Some aspects of natural resources can be easily valued monetarily (e.g. the market price of the timber from a tree). Others are extremely difficult or impossible to value monetarily, or their monetary value may be a meaningless concept (e.g. a tree's value as a habitat to other species). This means that a 'full' economic valuation of a resource is always an unquantifiable underestimate of its true value.51


Ecosystem management—An approach to maintaining or restoring the composition, structure, function and delivery of services of natural and modified ecosystems for the goal of achieving sustainability. Ecosystem management is based on an adaptive, collaboratively developed vision of desired future conditions that integrates ecological, socioeconomic and institutional perspectives, applied within a geographic framework, and defined primarily by natural ecological boundaries.52


Edge habitat—Edge habitat as defined by Yahner (1988) is “the junction of two different landscape elements (e.g. plant community type, successional stage, or land use).”53


Essential ecological attributes (EEAs)—The defining attributes of an ecological system or landscape. landscape condition, biotic condition, chemical and physical characteristics, ecological processes, hydrology and geomorphology, and natural disturbance regimes summarize the major ecological features in any system by capturing relevant scientific information in a limited number of discrete, but not necessarily independent categories.54


Estuary—A coastal ecological ecosystem that is partially enclosed, receives freshwater input from land, and has a horizontal fresh-salt salinity gradient; the average salinity of estuarine waters is defined as being 30 practical salinity units (PSU) for at least 1 month per year.55


Evaporation—(1) The physical process by which a liquid (or a solid) is transformed to the gaseous state.  (2) The process by which water is changed from a liquid to a vapor.  In hydrology, evaporation is vaporization that takes place at a temperature below the boiling point.  Also see evapotranspiration.56


Evapotranspiration—( 1) The process by which plants take in water through their roots and then give it off through the leaves as a by-product of respiration; the loss of water to the atmosphere from the earth’s surface by evaporation and by transpiration through plants. (2) The quantity of water transpired (given off), retained in plant tissues, and evaporated from plant tissues and surrounding soil surfaces. (3) The sum of evaporation and transpiration from a unit land area. (4) The combined processes by which water is transferred from the earth surface to the atmosphere; evaporation of liquid or solid water plus transpiration from plants. (5) The combined evaporative-type processes, including evaporation, interception, and transpiration, usually applied to biological systems. Evapotranspiration occurs through evaporation of water from the surface, evaporation from the capillary fringe of the groundwater table, and the transpiration of groundwater by plants (Phreatophytes) whose roots tap the capillary fringe of the groundwater table.57



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Fen—Low land covered wholly or partly with water; a moor or marsh.  A type of wetland that accumulates peat deposits.  Fens are less acidic than bogs, deriving most of their water from groundwater rich in calcium and magnesium.58 Fens are rare in the Great Lakes region and across North America. Because they are a rare habitat type, they also share a disproportionate number of rare, threatened and endangered species.59


Fishery(1) Generally, a fishery is an activity leading to harvesting of fish. It may involve capture of wild fish or raising of fish through aquaculture; 2) A unit determined by an authority or other entity that is engaged in raising or harvesting fish. Typically, the unit is defined in terms of some or all of the following: people involved, species or type of fish, area of water or seabed, method of fishing, class of boats, and purpose of the activities; 3) The combination of fish and fishers in a region, the latter fishing for similar or the same species with similar or the same gear types.60


Floodplain—(1) (FEMA) Any normally dry land area that is susceptible to being inundated by water from any natural source.  This area is usually low land adjacent to a river, stream, watercourse, ocean or lake. (2) A strip of relatively smooth land bordering a stream, built of sediment carried by the stream and dropped in the slack water beyond the influence of the swiftest current.  It is called a living flood plain if it is overflowed in times of high water but a fossil flood plain if it is beyond the reach of the highest flood.  (3) The lowland that borders a stream or river, usually dry but subject to flooding.  (4) The transversely level floor of the axial-stream drainageway of a semi-bolson or of a major desert stream valley that is occasionally or regularly alluviated by the stream overflowing its channel during flood.  (5) The land adjacent to a channel at the elevation of the bankfull discharge, which is inundated on the average of about 2 out of 3 years.  The floor of stream valleys, which can be inundated by small to very large floods.  The one-in-100-year floodplain has a probability of 0.01 chance per year of being covered with water.  (6) That land outside of a stream channel described by the perimeter of the maximum probable flood.  Also referred to as a flood-prone area.61


Flow regime—The characteristic patterns in a river’s flow over the course of time, ranging from hours, days, seasons, years and longer. Five critical components of the flow regime regulate ecological processes in river ecosystems, including magnitude, duration, frequency, timing, and rate of change. River flow regimes show regional patterns that are determined largely by river size and by geographic variation in climate, geology, topography and vegetative cover.62


Flow velocity—(1) The volume of water flowing through a unit cross-sectional area of an aquifer.  Also referred to as specific discharge.  (2) Speed at which water moves during a flood.  Velocities usually vary across the floodplain.  They are usually greatest near the channel and lowest near the edges of the floodplain.63


Food chain—A succession of organisms in an ecological community that constitutes a continuation of food energy from one organism to another as each consumes a lower member and in turn is preyed upon by a higher member.64


Forest—In general, an area or biotic community dominated by trees. Areas characterized by tree cover (natural or semi-natural woody vegetation, generally greater than 6 meters tall); tree canopy accounts for 25-100 percent of the cover.65



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Geographic framework—In Great Lakes Inform, a geographic framework is a nested geographic hierarchy used to index resources. The geographic framework allows users to drill down scales of content. For example, articles in the Knowledge Network are written in sets of three nested geographic scales for each major ecosystem type. Likewise, projects and assessment information found in Project Tracking and Assess & Adapt can be viewed for any of the three nested geographic scales.


Geology—The study of the physical nature and history of the earth. See also geomorphology.66


Geomorphology—That branch of both physiography and geology that deals with the form of the earth, the general configuration of its surface, and the changes that take place in the evolution of land forms. The term usually applies to the origins and dynamic morphology (changing structure and form) of the earth’s land surfaces, but it can also include the morphology of the sea floor and the analysis of extraterrestrial terrains. Sometimes included in the field of physical geography, geomorphology is really the geological aspect of the visible landscape.67


Glacial till—Till is the mixture of rocks, boulders and soil picked up by a moving glacier and carried along the path of the ice advance.  As a glacier moves, it deposits this till along its path — on the sides of the ice sheet, at the toe of the glacier when it recedes and across valley floors when the ice sheet melts.  These till deposits are akin to the footprint of a glacier and are used to track the movement of glaciers.  These till deposits can also be good sources of ground water, if they do not contain significant amounts of impermeable clays.68 In the Great Lakes region, abundant glacial till makes ideal conditions for agriculture throughout much of the basin.69


Global heat balance—The equilibrium that exists on the average between the radiation received by the Earth and atmosphere from the Sun and that emitted by the Earth and atmosphere.70


Goods and services—Ecosystem goods and services can be defined as all benefits that humans receive from ecosystems.71 These benefits can be direct (e.g. food production) or indirect, through the functioning of ecosystem processes that produce the direct services.72 The Millennium Assessment classifies ecosystem goods and services into four categories (supporting, provisioning, regulating, and cultural).73


Gradient—In reference to a stream: degree of incline; slope of a stream bed.  The vertical distance that water falls while traveling a horizontal distance downstream.74   


Groundwater—(1) Generally, all subsurface water as distinct from surface water; specifically, the part that is in the saturated zone of a defined aquifer.  (2) Water that flows or seeps downward and saturates soil or rock, supplying springs and wells.  The upper level of the saturated zone is called the water table.  (3) Water stored underground in rock crevices and in the pores of geologic materials that make up the Earth’s crust.  Ground water lies under the surface in the ground’s zone of saturation and is also referred to as phreatic water.75



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Habitat—The native environment or specific surroundings where a plant or animal naturally grows or lives.  The surroundings include physical factors such as temperature, moisture, and light together with biological factors such as the presence of food or predator organisms.  The term can be employed to define surroundings on almost any scale from marine habitat, which encompasses the oceans, to microhabitat in a hair follicle of the skin.76


Habitat suitability analysis—A habitat requires specific physical (and chemical) environmental conditions to support its biological community.  Searching a map of physical variables to find the specific environmental conditions to suit a habitat is called suitability analysis.  In other words, the appropriateness of an area to support a particular habitat is determined.  A similar approach can be applied to find the suitable conditions to support an individual species.77


Harvest— (Fishery) The total number or weight of fish caught and kept from an area over a period of time. Note that landings, catch and harvest are different.78 Other types of biological resource use include hunting and collecting terrestrial animals, gathering terrestrial plants, logging and wood harvesting, and harvesting aquatic resources other than fish.79


Headwaters—(1) The source and upper reaches of a stream; also the upper reaches of a reservoir.  (2) The water upstream from a structure or point on a stream.  (3) The small streams that come together to form a river.  Also may be thought of as any and all parts of a river basin except the mainstream river and main tributaries.80


Hydrologic cycle—(1) The cycling of water from the atmosphere, onto and through the landscape and eventually back into the atmosphere. (2) The circuit of water movement from the atmosphere to the earth and return to the atmosphere through various stages or processes such as precipitation, interception, runoff, infiltration, percolation, storage, evaporation and transportation. Also referred to as the water cycle and hydrogeologic cycle.81



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Index of Biological Integrity—The Index of Biological Integrity, or IBI, is a system used to assess the health of a watershed or body of water.82 On Great Lakes Inform, Vegetation IBI’s are used to measure the health of coastal wetlands based on plant assemblages.

Invasive plant—Invasive plants are introduced species that can thrive in areas beyond their natural range of dispersal. These plants are characteristically adaptable, aggressive and have a high reproductive capacity. Their vigor combined with a lack of natural enemies often leads to outbreak populations.83



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Keystone species—Keystone species have a disproportionate influence on their ecosystem, due to their physical size or their activities that affect the surrounding environment. For example, beavers change water flow substantially by building dams. Diporeia, a tiny shrimp-like invertebrate species found at the bottom of the Great Lakes, is also a keystone species because it is the main food source of many Great Lakes fishes.84 Changes in the population size of a keystone species will have correspondingly large effects on the ecosystem.85



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Lake—A considerable body of inland water or an expanded part of a river.86


Landform—(Geography) (1) A discernible natural landscape that exists as a result of wind, water or geological activity, such as a plateau, plain, basin or mountain. (2) A three dimensional part of the land surface, formed of soil, sediment or rock that is distinctive because of its shape, that is significant for land use or to landscape genesis, that repeats in various landscapes, and that also has a fairly consistent position relative to surrounding landforms.87 Common landforms in the Great Lakes region include basins, ridges, bluffs and plains.88


Landscape—(Ecology) A heterogeneous area composed of a cluster of interacting ecosystems that are repeated in similar form throughout the area.89


Landscape composition—The number, diversity and proportions of different habitat types within a landscape setting.90


Landscape conservation—A science-based framework for conserving fish and wildlife at a landscape scale that includes biological planning, conservation design, conservation delivery, outcome-based monitoring and assumption-driven research.91


Landscape pattern and structure—The spatial arrangement of habitat types within a landscape. Landscape patterns and structures can be defined for various scales, i.e. the distribution of trees of a certain age class within a forest stand, or the mosaic pattern of wetland habitat within a larger landscape composed of urban and rural land cover.92


Limiting factor—A condition whose absence or excessive concentration is incompatible with the needs or tolerance of a species or population and which may have a negative influence on their ability to thrive or survive. A factor such as temperature, light, water or a chemical that limits the existence, growth, abundance or distribution of an organism.93



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Marsh—A term frequently associated with wetlands.  An area of soft, wet, low-lying land characterized by grassy vegetation that does not accumulate appreciable peat deposits and often forms a transition zone between water and land.  A tract of wet or periodically inundated treeless land, usually characterized by grasses, cattails or other monocotyledons (sedges, lilies, irises, orchids, palms, etc.).  Marshes may be either fresh or saltwater, tidal or nontidal.94


Microbe—Short for Microorganism. Small organisms that can be seen only with the aid of a microscope. The term encompasses viruses, bacteria, yeast, molds, protozoa and small algae; however, microbe is used most frequently to refer to bacteria. Microbes are important in the degradation and decomposition of organic materials added to the environment by natural and artificial mechanisms.95


Migration (Fishery) (1) Systematic (as opposed to random) movement of individuals of a stock from one place to another, often related to season. A knowledge of the migration patterns helps in targeting high concentrations of fish and managing shared stocks; (2) The movements of fish from feeding ground to spawning ground and back again, from nursery ground to feeding ground, and from spawning ground to nursery ground.96 In general, migration is a seasonal movement of large groups of animals from one location to another. May also apply to birds, insects, and mammals.97  Characteristics that are common to most migration patterns include persistence, linearity, special start-and-stop behaviors, and stored energy.98



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Natural disturbance regime—A natural disturbance has been defined by White and Picket (1985) as "any relatively discrete event in time that disrupts ecosystem, community or population structure and changes resources, substrate availability, or the physical environment.” Given sufficient knowledge of the natural history of a region, patterns of natural disturbance regimes can be described. The frequency, intensity (i.e., degree of disturbance), extent (i.e., spatial coverage) and duration of the events taken together are referred to as the “disturbance regime.”99


Natural resource—A material source of wealth, such as timber, fresh water, or a mineral deposit, that occurs in a natural state and has economic and/or social value. Natural resources are considered nonrenewable when they do not naturally replenish themselves within the limits of human time or renewable when they are more or less continuously replenished in the course of natural events within the limits of human time.100


Nutrient—(1) An element or compound essential to life, including carbon, oxygen, nitrogen, phosphorus and many others. (2) Animal, vegetable or mineral substance which sustains individual organisms and ecosystems. (3) That portion of any element or compound in the soil that can be readily absorbed and assimilated to nourish growing plants, e.g., nitrogen, phosphorus, potassium, iron.101


Nutrient Cycle—The cyclic conversions of nutrients from one form to another within biological communities. A simple example of such a cycle would be the production and release of molecular oxygen (O2) from water (H2O) during photosynthesis by plants and the subsequent reduction of atmospheric oxygen to water by the respiratory metabolism of other biota. The cycle of nitrogen is much more complex, with the nitrogen atom undergoing several changes in oxidation state (N2, NO3 –, R — NH2, and NH4 +, among others) during the cycling of this element through the biological community, and into the air, water or soil, and back.102



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Organism—An individual living thing that can react to stimuli, reproduce, grow, and maintain homeostasis. It can be a virus, bacterium, protist, fungus, plant or an animal.103



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Patch—(Habitat) A relatively uniform area of habitat sharing similar ecological attributes throughout.  A patch may be defined at different scales.104


Patch extent—(Habitat) The size (area) and shape of a habitat patch. Extent may be reported for broad land cover classes, for finer subunits or both.105


pH (Hydrogen Ion Concentration, or Potential of Hydrogen)—(1) A convenient method of expressing the acidity or basicity of a solution in terms of the logarithm of the reciprocal (or negative logarithm) of the hydrogen ion concentration. The pH scale runs from 0 to 14; a pH value of 7.0 indicates a neutral solution. Values above 7.0 pH indicate basicity (basic or alkaline solutions); those below 7.0 pH indicate acidity (acidic solutions). Natural waters usually have a pH between 6.5 and 8.5. Because the units are derived from common logarithms, a difference of one pH unit indicates a tenfold difference in acidity; similarly, a difference of two units indicates a hundredfold difference in acidity. The term originally derived from “potential of hydrogen,” or hydrogen power.106


Pond—A body of water smaller than a lake, often artificially formed.107 Many ponds are seasonal, lasting just a couple of months (such as sessile pools).108


Population—(Ecological) A group of organisms of one species that interbreed and live in the same place at the same time.109


Persistence—See viability


Productivity—The accrual of matter and energy in biomass.110


Project area (also Scope)—The place where the biodiversity of interest to a conservation project is located. Note that in some cases, project actions may take place outside of the defined project area. In a few cases, a conservation project may not focus on biodiversity in a specific area but instead will have a project scope that focuses on a population of wide-ranging animals, such as migratory birds.111



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Riparian—Pertaining to the banks of a river, stream, waterway, or other, typically, flowing body of water as well as to plant and animal communities along such bodies of water.  This term is also commonly used for other bodies of water, e.g., ponds, lakes, etc., although littoral is the more precise term for such stationary bodies of water.  Also refers to the legal doctrine (riparian doctrine and riparian water rights) that says a property owner along the banks of a surface water body has the primary right to withdraw water for reasonable use.  Also see riverine.112


River—A  natural stream of water of considerable volume, larger than a brook or creek.  A river has its stages of development, youth, maturity and old age.  In its earliest stages, a river system drains its basin imperfectly; as valleys are deepened, the drainage becomes more perfect, so that in maturity the total drainage area is large and the rate of erosion high.  The final stage is reached when wide flats have developed and the bordering lands have been brought low.113


Riverine—(1) Relating to, formed by or resembling a river including tributaries, streams, brooks, etc.  (2) Pertaining to or formed by a river; situated or living along the banks of a river, for example, a “riverine ore deposit.”  Also see riparian.114



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Sedimentary rock—(Geology) Rock formed of sediment, especially from mechanical, chemical or organic processes, and specifically:  (1) clastic rock, such as conglomerate, sandstone and shale, formed of fragments of other rock transported from their sources and deposited in water; and (2) rocks formed by precipitation from solution, as rock salt and gypsum, or from secretions of organisms, such as most limestone.  Many sedimentary rocks show distinct layering, which is the result of different types of sediment being deposited in succession.115   


Salinity—(1) The concentration of dissolved salts in water or soil water. Salinity may be expressed in terms of a concentration or as an electrical conductivity. When describing salinity influenced by seawater, salinity often refers to the concentration of chlorides in the water. (2) The relative concentration of salts, usually sodium chloride, in a given water sample. It is usually expressed in terms of the number of parts per thousand (‰) or parts per million (ppm) of chloride (Cl). Although the measurement takes into account all of the dissolved salts, sodium chloride (NaCl) normally constitutes the primary salt being measured. Salinity can harm many plants, causing leaves to scorch and turn yellow and stunting plant growth. As a reference, the salinity of seawater is approximately 35‰ or 35,000 ppm.116


Species—A group of individuals having a common origin and a continuous breeding system.117


Stream—A general term for a body of flowing water; natural water course containing water at least part of the year. In hydrology, the term is generally applied to the water flowing in a natural channel as distinct from a canal.  More generally, as in the term stream gaging, it is applied to the water flowing in any channel, natural or artificial. Some classifications of streams include, in relation to time:

[1] Ephemeral streams — Streams which flow only in direct response to precipitation and whose channel is at all times above the water table.

[2] Intermittent or seasonal streams — Streams which flow only at certain times of the year when it receives water from springs, rainfall, or from surface sources such as melting snow.

[3] Perennial streams — Streams which flow continuously. And, in relation to ground water:

[4] Gaining streams — Streams or a reach of a stream that receive water from the zone of saturation.  Also referred to as an effluent stream.

[5] Insulated streams — Streams or a reach of a stream that neither contribute water to the zone of saturation nor receive water from it.  Such streams are separated from the zones of saturation by an impermeable bed.

[6] Losing streams — Streams or a reach of a stream that contribute water to the zone of saturation.  Also referred to as an influent stream.

[7] Perched streams — Perched streams are either losing streams or insulated streams that are separated from the underlying ground water by a zone of aeration.118


Streambank—The usual boundaries, not the flood boundaries, of a stream channel.  Right and left banks are named facing downstream (in the direction of flow).119


Streambed—The channel through which a natural stream of water runs or used to run, as a dry streambed.120


Stream channel—The bed where a natural stream of water runs or may run; the long narrow depression shaped by the concentrated flow of a stream and covered continuously or periodically by water.121


Stream reach—The continuous portion of a stream channel and adjoining floodplain from one selected point to another, usually measured along the thalweg of the channel.122


Stream segment—(Water planning) Surface waters of an approved planning area exhibiting common biological, chemical, hydrological, natural and physical characteristics and processes.  Segments will normally exhibit common reactions to external stresses, for example, discharge or pollutants.123


Succession—(Biology) (1) The ecological process of sequential replacement by plant communities on a given site as a result of differential reproduction and competition.  (2) Directional, orderly process of change in a living community in which the community modifies the physical environment to eventually establish an ecosystem which is as stable as possible at the site in question.124


Surface water—(1) An open body of water such as a stream, lake or reservoir.  (2) Water that remains on the Earth’s surface; all waters whose surface is naturally exposed to the atmosphere, for example, rivers, lakes, reservoirs, ponds, streams, impoundments, seas, estuaries, etc., and all springs, wells or other collectors directly influenced by surface water.  (3) A source of drinking water that originates in rivers, lakes and run-off from melting snow.  It is either drawn directly from a river or captured behind dams and stored in reservoirs.125


Suspended solids (SS)—Solids which are not in true solution and which can be removed by filtration.  Such suspended solids usually contribute directly to turbidity.  Defined in waste management, these are small particles of solid pollutants that resist separation by conventional methods.  Suspended solids (along with biochemical oxygen demand — BOD) is a measurement of water quality and an indicator of treatment plant efficiency.  Also see suspended particulate matter.126


Suspended Particulate Matter—A sample drawn from natural water or from a wastewater stream consists of a mixture of both dissolved and suspended matter.  Those solid materials that are retained on a filter prescribed by the specific technique being followed are referred to as particulate matter. Suspended particulate matter may be composed of volatile (organic) and fixed (mineral) compounds.127


Swamp—A term frequently associated with wetlands.  Wet, spongy land; low saturated ground, and ground that is covered intermittently with standing water, sometimes inundated and characteristically dominated by trees or shrubs, but without appreciable peat deposits.  Swamps may be fresh or salt water and tidal or non-tidal.  It differs from a bog in not having an acid substratum.128 Common Great Lakes swamps include lowland hardwood swamps, coniferous swamps, coniferous bogs, floodplain forests, alder thickets and shrub carrs.129



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Terrestrial—Living or growing on land rather than in water or air.130 Terrestrial habitats of the Great Lakes include forests, woodlands, dunes, beaches, prairies, alvars and more.


Topography—The general configuration of the land surface including relief and position of natural and man-made features.131


Total Maximum Daily Load (TMDL)—A TMDL establishes the maximum amount of a pollutant allowed in a waterbody and serves as the starting point or planning tool for restoring water quality.132


Toxic—(1) Describing a material that can cause acute or chronic damage to biological tissue following physical contact or absorption. (2) Substances that even in small quantities may poison, cause injury or cause death when eaten or ingested through the mouth, absorbed through the skin or inhaled into the lungs.133


Trace elements—Elements essential to plant or animal life but required only in small amounts, such as the trace amounts of manganese, zinc, iron, molybdenum, cobalt and copper.134


Trace metals—A general term for metals found in small quantities (less than 1 milligram per liter — mg/l) in water, usually due to their insolubility.135


Tributary—(1) A stream which joins another stream or body of water.  (2) A stream or other body of water, surface or underground, which contributes its water, even though intermittently and in small quantities, to another and larger stream or body of water.136


Trophic structure (also trophic level)—(1) Classification of natural communities or organisms according to their place in the food chain. Green plants (producers) can be roughly distinguished from herbivores (consumers) and carnivores (secondary consumers); (2) Group of organisms eating resources from a similar level in the energy cycle; (3) Position in food chain determined by the number of energy-transfer steps to that level. Plant producers constitute the lowest level, followed by herbivores and a series of carnivores at the higher levels.137



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Vegetation structure—The way in which vegetation is arranged in three-dimensional space. “Structure” usually refers to vertical structure.  However, horizontal structure could also be measured with techniques based on cover, density or distribution.138


Viability—The status or “health” of a population of a specific plant or animal species. More generally, viability indicates the ability of a conservation target to withstand or recover from most natural or anthropogenic disturbances and thus to persist for many generations or over long time periods. Technically, the term “integrity” should be used for ecological communities and ecological systems with “viability” being reserved for populations and species.139



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Water cycle—The cycle of evaporation and condensation that controls the distribution of the Earth’s water as it evaporates from bodies of water, condenses, precipitates and returns to those bodies of water.  Also referred to as the hydrologic cycle.140


Watershed—(1) An area that, because of topographic slope, contributes water to a specified surface water drainage system, such as a stream or river.  An area confined by topographic divides that drains a given stream or river.  (2) (Catchment) The natural or disturbed unit of land on which all of the water that falls (or emanates from springs or melts from snowpacks), collects by gravity, and fails to evaporate, runs off via a common outlet.  (3) All lands enclosed by a continuous hydrologic drainage divide and lying upslope from a specified point on a stream; a region or area bounded peripherally by a water parting and draining ultimately to a particular water course or body of water.  Also referred to as water basin or drainage basin.  (4) A ridge of relatively high land dividing two areas that are drained by different river systems.  Also referred to as water parting.141


Weathering—(1) The physical disintegration or chemical decomposition of rock due to wind, rain, heat, freezing, thawing, etc.  (2) The response of materials that were once in equilibrium within the Earth’s crust to new conditions at or near contact with water, air or living matter.  The breakdown of rock through a combination of chemical, physical, geological and biological processes.  The ultimate outcome is the generation of soil.142


Wetland—An area that is periodically inundated or saturated by surface or groundwater on an annual or seasonal basis, that displays hydric soils, and that typically supports or is capable of supporting hydrophytic vegetation.143   



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