|
A
Abrasion: the process of wearing down or rubbing away by means of
friction
Acid neutralizing capacity: ANC; the property of water that reacts
with an acid; recently replacing alkalinity.
Adfluvial: descriptive of migration pattern of fish species that
spawn in a freshwater stream then migrate to a freshwater lake for
growth.
Aerobic: said of an organism, such as a bacterium, that can only live
or function in the presence of free oxygen; also said of processes or
conditions that can only occur in the presence of free oxygen
Aggregation: a collection of material at a given place
Alga (pl. Algae): any of various primitive, chiefly aquatic,
one-celled or multicellular plants that lack true stems, roots, and
leaves but usually contain the green pigment called chlorophyll
Alkalinity: property of water containing alkaline substances, mainly
bicarbonate in natural water, expressed as parts per million (ppm); see
acid neutralizing capacity.
Allochthonous: describing organic matter that is produced on land and
then is moved to the stream, compare autochthonous.
Allochthony: study of production, transport, and use of allochthonous
matter in a stream.
Allopatric: not existing in the same stream; compare sympatric.
Alluvial: Of or pertaining to material deposited by a stream or
flowing water.
Anadromous: descriptive of fish that spawn in a stream and migrate to
the Ocean for major growth; compare adfluvial.
Anadromy: form of fish life history with spawning in a stream and
major growth in the ocean.
Anaerobic: said of an organism, such as a bacterium, that does not
require free oxygen to live or function; also said of processes or
conditions that do not require oxygen
ANC: acid neutralizing capacity; see alkalinity.
Angiospermae: any of a class of plants that is identified by having
their seeds enclosed in an ovary
Anthropogenic: caused through human activity; usually applied to
sediment or other pollutant.
Aquifer: layer of groundwater beneath land surface.
Artesian: spring or well arising from pressure in deep aquifer.
Autochthonous: term applied to organic matter produced by aquatic
plants within the stream; compare allochthonous.
Autochthony: study of organic matter production within a stream;
compare photosynthesis, primary production.
Autotroph: green plant, "self-feeding;" compare heterotroph.
Autotrophy: study of production by green plants; compare
heterotrophy.
Backwater: water held or pushed back by or as if by a dam or current;
especially a body of stagnant or still water thus formed
Bank Stabilization: Methods of supporting the structural integrity of
earthen stream channel banks with structural supports to prevent bank
slumping and undercutting of riparian tress, as well as overall erosion.
Recommended bank stabilizing techniques include the use of willow
stakes, overlapping riprap, or brush bundles.
Bar: anything that impedes or prevents; an obstacle, such as a
sandbar in a river that impedes the flow of water
Base flow: flow of a stream when it is composed entirely of
groundwater from springs.
Baseline discharge: base flow.
Bedload: soil, rocks, and other debris rolled along the bottom of a
stream by moving water, in contrast to siltload, which is carried in
suspension
Bedrock: the solid rock that underlies soil, sand, clay, gravel, and
loose material on the earth's surface
Benthic: referring to the bottom of streams, takes, and oceans; see
benthos.
Benthos: assemblage of organisms inhabiting the bottoms of streams,
lakes, and oceans.
Bigeminus: daily pattern of stream invertebrate drift with two peaks
a major one at full darkness and a lesser one before dawn; compare alternans.
Biodiversity: property of a community of organisms varying in number
of species, in their relative abundance, and life histories.
Biofilm: accumulation of biological matter on the surface of stone
and wood, consisting mainly of algae, bacteria, and fungi; see periphyton, epilithon.
Biogeographic region: Any region delineated by its biological and
geographic characteristics.
Biomass: the combined weight of all living organisms in a given area
Biospeleology: study of biological communities in caves.
Biota: assemblages of living organisms.
Biotic: composed of plants and animals
Bivoltines: having two generations, or cohorts, per year.
Borer: a functional group of organisms that feed by boring into wood.
Brackish: containing some salt; briny
Buffer strip: a strip of vegetation that is left along the margins of
a stream or a river to reduce the impact of logging activities on that
stream or river
Buffering capacity: ability of water to resist change in its chemical
property when receiving a toxicant.
Calcareous: composed of, containing, or characteristic of calcium
carbonate, calcium, or limestone; chalky
Calcium carbonate: a colorless or white crystalline compound that
occurs naturally in chalk, limestone, marble, and other forms
Calorie: amount of heat energy required to raise one cubic centimeter
of pure water one degree Celsius.
Capture net: fine-meshed net made of silk by some caddisfly species
to filter fine particles of organic matter from water currents for food.
Carapace: hard covering of the head and thorax of some aquatic
insects and crustaceans.
Carbon: a naturally abundant nonmetallic element that occurs in many
inorganic and in all organic compounds
Carrying capacity: maximum level to which the biomass of an animal
population can reach in accordance with the quality of its environment.
Cascade: a waterfall or a series of small waterfalls over steep rocks
Catadromous: descriptive of fish species that spawn in the ocean and
migrate to freshwater for growth, the eel is the best known species;
compare anadromous.
Catadromy: the type of life history exhibited by catadromous species;
compare anadromy.
Catchment: total area drained by a stream or river, older usage:
watershed.
Catchnet: net made by some species of caddisfly larvae to filter food
particles from water currents; see capture net.
Cellulose: an amorphous carbohydrate polymer, the main constituent of
all plant tissues and fibers, that is used in the manufacture of many
fibrous products, including paper, textiles, and explosives
Channel: the bed of a stream or river (active channel ~ the lower
limit of terrestrial plants)
Channelization: Straightening of the meanders in a river systerm to
create more navigable waterways, or when accompanied by channel
deepening to provide flood control.
Chitin: a semitransparent, horny substance that forms the principal
component of the shells of crustaceans, the exoskeletons of insects, and
the cell walls of certain fungi
Circadian: approximately 24 hours, descriptive of some rhythmic
animal behaviors.
Clay: a very fine-grained sediment that becomes plastic and acts like
a lubricant when wet; consists primarily of hydrated silicates of
aluminum and is widely used in making bricks, tiles, and pottery
Climatic cycle: the cyclic changes in weather patterns in a
geographical area over time
Coarse particulate organic matter: CPOM; particles of organic matter
ranging from about 1/32 inch (one millimeter) up to a fallen tree;
compare FPOM.
Cohort production interval: CPI; period of time that a cohort is
alive and growing; not in egg, pupa, or other quiescent stage.
Cohort: group of animals or plants hatched, born, or established at
the same time; a generation.
Coldwater: descriptive of salmonid fishes; implies they need cold
water.
Colluvial deposits: any loose, heterogeneous mass of soil materials
or rock fragments deposited along the base of hillslopes or more gentle
slopes by rainwash, sheetwash (debris flows) or slow, continuous
downslope creep.
Colonization: the process or act of establishing a colony or
colonies; see also Colony
Colony: a group of the same kind of plants or animals living together
Community: a group of one or more populations of plants and/or
animals using a common area; an ecological term used in a broad sense to
include groups of plants and animals of various sizes and degrees of
integration
Conditioning (of organic matter): transforming fresh organic matter
into form more palatable to invertebrate consumers; accomplished
primarily by bacteria and fungi.
Conduit spring: freshwater spring where water has flowed through
large subsurface openings; compare diffuse spring.
Confined aquifer: subsurface layer of water under pressure from
impermeable rock strata above and below the aquifer, compare unconfined
aquifer.
Conifer: the most important order of the Gymnospennae, comprising a
wide range of trees, mostly evergreens that bear cones and have needle-
shaped or scale-like leaves; its timber is commercially identified as
softwood
Coniferous: of or pertaining to conifers
Conservation tillage: suite of agricultural practices aimed at
reducing erosion and retaining precipitation on land.
Continuum: a continuous extent, succession, or whole, no part of
which can be distinguished from neighboring parts except by arbitrary
division
Copepod: any of numerous small marine and freshwater crustaceans of
the order Copepoda
Cosmopolitan: found throughout the world.
CPOM: see coarse particulate organic matter.
Creep: very slow downslope movement of soil resulting from
deformation of soil under the influence of gravity; rate of speed is
fractions of an inch per year
Crenon: area of headwater springs.
Crown: the upper part of a tree or other woody plant that carries the
main branching system and foliage and that surmounts at the crown's base
a more or less clean stern
Crustacean: any of various predominantly aquatic arthropods of the
class Crustacea, including lobsters, crabs, shrimps, and barnacles,
characteristically having a segmented body, a chitinous exoskeleton, and
paired, jointed limbs
Cyanobacteria: blue-green algae; believed to be the first oxygen-
producing organisms with fossils estimated at 2.3 billion years old.
Debris flow: very fast movement of water-charged soil and vegetation,
both dead and alive, down stream channels; rate of speed is in feet per
second
Debris slide: very fast movement of soil, commonly containing a high
concentration of water, down hillslopes under the influence of gravity;
the initial sliding surface is generally 3 to 12 feet below the surface
of the ground,
Debris torrent: a slurry of debris, soil, and water that occurs where
a landslide enters a steep channel and moves downstream during
conditions of severe flooding
Decapitated: River that does not conform to the original RCC in that
it does not begin in a wooded area.
Decay: to decompose; to rot; in wood, the decomposition by fungi or
other microorganisms results in softening, progressive loss of strength
and weight, and changes in texture and color
Deciduous: pertaining to any plant organ, such as a leaf, that is
shed naturally; also referring to perennial plants that shed their
leaves and are therefore leafless for some time during the year
Decomposers: organisms that accomplish the decomposition of organic
matter, such as bacteria and fungi.
Delta: the usually triangular deposit of alluvial material at the
mouth of a river
Denitrification: process of transforming nitrate in stream water back
into atmospheric nitrogen.
Denitrifying bacteria: organisms responsible for denitrification.
Detritus: any disintegrating organic material or debris
Detritus pool: total accumulation of nonliving organic matter in
streams.
Detritivore: an organism that feeds on decaying organic materials
Diapause: temporary cessation of metabolism in some insects, usually
to survive severe environmental conditions.
Diatom: any of various minute, one celled or colonial algae of the
class
Dichotomous: stream tributary pattern, branching by twos.
Diel periodicity: 24-hour pattern of behavior in plants and animals;
involved with many species of stream invertebrates subject to drift.
Diffuse spring: freshwater spring fed by groundwater that arrives at
the spring through many small interstices in rock and soil.
Dioecious: possessing male and female flowers on separate, unisexual
plants; compare monoecious.
Discharge: flow of water in a stream, measured in units of cubic feet
per second (cfs) or cubic meters per second (cms),
Discharge area: that part of a catchment where groundwater exits the
surface as springs; compete recharge area.
Discontinuity: obstacle to the stream continuum; see reset.
Dissolved organic matter: DOM; organic matter in dimension smaller
than 0.45 micron (about 1/50,000 inch).
Diversity: the relative degree of abundance of species of plants and
animals, functions, communities, habitats, or habitat features per unit
of area
Dom: Dissolved organic matter.
Drainage basin: watershed, catchment.
Duckweed: floating plants with tiny leaves and roots; genus Lemna
dynamics: processes and functions expressed as rates.
Dynamic: characterized by or tending to produce continuous change
Ecological integrity: Maintenance of the structure and functional
attributes characteristic of a particular locale, including normal
variability.
Ecological niche: functional position of an organism in a community.
Ecological: referring to a relationship between living organisms and
their non-living, physical environment
Ecology: scientific discipline treating the relationships among
living organisms and their environment.
Ecoregions: Ecological regions that have broad similarities with
respect to soil, relief, and dominant vegetation.
Ecosystem: spatial area inhabited by organisms living together in an
orderly manner, interdependent among their cohabitants and with their
environment.
Ecotone: transition zone between different biological communities;
example is riparian zone.
Eddy (pl. Eddies): a current, as of water or air, moving contrary to
the direction of the main current, especially in a circular motion
Effluent stream: stream flowing below the water table and receiving
water from the groundwater; compare influent stream.
El Nino: a regional or global oceanic-atmospheric disturbance whose
manifestations range from increased sea surface temperature in the
tropical east Pacific to aberrant rainfall patterns
Emergent plants: Aquatic plants that are rooted in the sediment, but
whose leaves are at or above the water surface. These wetland plants
provide habitat for wildlife and waterfowl in addition to removing urban
pollutants.
Energy: calories needed by a biological system to function or do
work.
Engulfer: functional group of predators who take in the whole prey
animal in their feeding; compare piercer.
Epigean: above ground habitats; open streams, forests; compare hypogean
Epilimnion: a thermally stratified lake, the turbulent layer of water
that extends from the surface to the metalimnion.
Epilithon: surface film on stones, consisting of algae, bacteria,
fungi, and other organisms and organic matter.
Erosion: the group of processes, including weathering, dissolution,
abrasion, corrosion, and transportation, by which earthy or rock
material is removed from any part of the earth's surface
Estuary: the wide, lower course of a river where its current is met
and influenced by the tides; it also is defined as an arm of the sea
that extends inland to meet the mouth of a river
Eurythermic: preferring a wide range of temperature; characteristic
of warmwater fish species.
Eutrophic: overly rich and productive; descriptive of a water body
that is over-fertilized, as with organic pollution
Eutrophication: the state of being eutrophic; generally a perjorative
term.
Evapotranspiration: water loss from a plant or tree; combination of
evaporation and transpiration.
Exoskeleton: hard exterior covering of insects and crustaceans,
giving support to the body.
Fauna: assemblage of animals.
Feeding guild: group of animals using a common type of food.
Ferric oxide: insoluble compound of iron and oxygen, found where
ferrous compounds in groundwater reach an oxygen-containing atmosphere.
Ferrous: descriptive of iron compounds in dissolved form.
Filterer: functional group that filters fine particles of organic
matter from stream currents; many caddishly and black fly larvae; a
subdivision of collectors.
Fine particulate organic matter: FPOM; nonliving organic matter
ranging from 1/50,000 inch (0.45 micron) to 1/32 inch (one millimeter);
compare CPOM.
First-order stream: see Stream order
Flood pulse concept: The idea that the pulsing of river discharge,
the flood pulse, is the major force controlling biota in
river-floodplain systems. Lateral exchange between the floodplain and
river channel, and nutrient cycling within the floodplain, are
postulated to have a more direct impact on biota than does nutrient
spiraling from upstream to downstream in the river channel; the bulk of
the animal biomass in such a system is believed to be derived from
production in the floodplain, not from downstream transport of organic
matter produced elsewhere in the basin.
Floodplain: Defined by hydrologists as the area flooded at a
recurrence interval of once in 100 years. Ecologists define floodplains
as areas that are periodically inundated (usually annually) by the
lateral overflow of rivers or lakes, or by direct precipitation or
ground water; the resulting physicochemical environment causes the biota
to respond by morphological, anatomical, physiological, phenological,
and/or ethological adaptations, and to produce characteristic community
structures.
Fluvial: Of or pertaining to a river or rivers (produced by the
action of stream or river)
Food chain: progression of feeding from prey to predators; compete
food web.
Food web: feeding pattern of predators and prey in a complex web of
different forms.
Forage: vegetation used for food by wildlife, particularly wild
ungulates, such as deer and elk
Forb: any herbaceous species of plant other than grasses, sedges, or
rushes; fleshy-leaved plants
FPOM: fine particulate organic matter.
Freestone stream: softwater stream usually with igneous rock and
cobble substrate.
Freshet: the sudden overflow of a stream or river resulting from a
heavy rain, or thaw, or both
Fry: early life history stage of fish after complete absorption of
the yolk sac.
Function: the natural or proper action for which an organism,
habitat, or behavior has evolved
Functional group: a group of organisms having the same function.
Fungus (pl. Fungi): mushrooms, truffles, molds, yeasts, rusts, etc.;
simply organized plants, unicellular or made of cellular filaments or
strands called hyphae, lacking chlorophyll; fungi reproduce asexually
and sexually with the formation of spores
Gallery forest: woodlands along the sides of a stream, often
referring to forest downstream from headwaters.
Gatherer: functional group that forages for food particles on the
streambed; a subdivision of collectors.
Genus: the first word in a binomial or scientific name
Geomorphology: the geological study of the configuration and
evolution of land forms
Germinate: to begin to grow, to sprout
Gouger: functional group that feeds on woody debris by gouging the
conditioned wood surface.
Gradient: a rate of inclination, a slope; an ascending or descending
part; an incline
Grazer: functional group that forages on periphyton, especially
algae.
Groundwater outcrop: where groundwater exits the land surface as a
spring.
Groundwater: water existing below the land surface.
Habitat: the sum total of environmental conditions of a specific
place occupied by a plant or animal, or a population of such species
Hardness: property of water rich in calcium and magnesium and that is
difficult to make suds with soap.
Hardwood: the wood of broad-leaved trees, and the trees themselves,
belonging to the botanical group Angiosperinae; distinguished from
softwoods by the presence of vessels
Headland: a point of land, usually high and with a sheer drop,
extending out into a body of water; a promontory
Hemimetabolous: life history trait where change in form from immature
insect to adult is incomplete, or "half-changed"; compare holometabolous.
Herbivorous: descriptive of feeding behavior on plants.
Hermaphroditic: descriptive of plant or animal having both male and
female reproductive organs.
Heterotroph: organism that depends on tissue produced by other
organisms; animals, fungi, bacteria.
Holistic: treating a subject in its entirety.
Holometabolous: life history trait of immature insects that change to
adults with complete transformation of form; compare hemimetabolous.
Home range: area used by an animal for all its needs, such as
feeding, reproduction, refuge from predators.
Hydraulic complexity: the system of variations in the velocity of the
water and the water-operated physical processes in a stream as governed
by the physical obstructions within the stream's channel
Hydraulic: of, involving, moved, or operated by a fluid, especially
water.
Hydrologic cycle: cycle of major events involving water of
precipitation, runoff to the ocean, evaporation, and again to
precipitation over land.
Hydrology: science of natural water, its form, transport, and transformatiom on land and in the atmosphere.
Hydrolysis: decomposition of a chemical compound by reaction with
water
Hypha (pl. Hyphae): filament or strand of a fungus thallus
(non-reproductive vegetative body) that is composed of one or more
cylindrical cells; increases by growth at its tip; gives rise to new
hyphae by lateral branching
Hypogean: below ground habitats, such as caves, hyporheic zone;
compare epigean.
Hyporheic: Pertaining to the hyporheos.
Hyporheos: The saturated zone beneath a river or stream consisting of
substrate, such as sand, gravel, and rock, with water-filled
interstitial pore. The zone often extends beyond the width of the stream
channel and is typically used by certain aquatic organisms during their
normal life cycle and as a refuge.
Impervious: incapable of being penetrated
Influent stream: stream flowing above the water table and losing
water into it.
Inorganic: involving neither organic life nor the products of organic
life; not composed of organic matter, especially minerals; contrast
Organic
Integrity: the state of being unimpaired; soundness; completeness;
unity
Interflow: subsurface flow of groundwater between catchments.
Intermittent: starting and stopping at intervals, such as a stream
whose flow is periodically interrupted
Interstices: tiny spaces within streambed sediments.
Invertebrate: an animal lacking a backbone or spinal column
Isopod: any of numerous crustaceans of the order Isopoda, which
includes the sow bugs and gribbles and shrimp.
Iteroparous: descriptive of an animal or plant that reproduces more
than once annually, or having more than one brood in its lifetime.
Jam: to block, congest, or clog, such as with fallen trees and other
woody debris.
Karst topography: landscape resulting from erosion of limestone
bedrock, such as caves, springs, sinkholes, and underground rivers.
Katharobic: descriptive of a group of protozoans found in springs and
small streams with oxygen-rich water.
Kilocalorie: 1,000 calories; calories on food packaging, etc. are
actually kilocalories.
Knickpoint: sharp irregularity in a stream-channel profile (commonly
bedrock intrusions)
Lacustrine: referring to lakes.
Landscape ecology: An emerging specialty that deals with the patterns
and processes of biological systems in spatially and temporally
heterogeneous environments.
Landscape perspective: A way to view interactive parts of a watershed
not necessarily all within one watershed.
Landslide: the dislodging and fall of a mass of earth and rock; see
also Debris flow; Earthflow
Large Woody Debris (LWD): wood > 10cm in diameter and > 1m in
length
Larva (pl. Larvae): the general term for the newly hatched, earliest
stage of any of various animals that undergo metamorphosis, such as
insects, frogs, and salamanders, and differ markedly in form and
appearance from the adult
Leachate: solution of dissolved organic matter from material such as
leaves, wood, and other nonliving matter.
Leaf pack: accumulation of leaves on streambed structures.
Lentic: pertaining to still water, lakes and ponds; compare lotic.
Lichen: a plant that is actually two plants in one; the outer plant
is a fungus that houses the inner plant, an alga
Life history: series of ecological events during major stages of life
cycle.
Lignin: the chief non-carbohydrate constituent of wood; a polymer
that functions as a natural binder and support for the cellulose fibers
of woody plants
Limestone stream: hardwater stream with streambed particles of
sedimentary origin; productive of invertebrates and fish; compare
freestone stream.
Limnocrene: spring pool.
Lithologic: referring to sedimentary rock.
Litter (forest): the uppermost layer of organic debris on the floor
of a forest; essentially the freshly fallen or slightly decomposed
vegetable material, mainly foliate or leaf litter, but also twigs, wood,
fragments of bark, flowers, and fruits
Litter fall: the fall of litter to the floor of the forest
Longitudinal profile: graphical representation of stream decrease in
elevation.
Lotic: pertaining to streams and rivers; flowing water; compare lentic.
Macroinvertebrate: stream invertebrate large enough to be seen easily
Macrophyte: large plant usually rooted in the streambed.
Marine: pertaining to the ocean.
Meander: to follow a winding and turning course, such as streams that
flow through level land; also said of a bend in a stream that has been
cut off from the main channel by the stream having shifted its course
Meiofanna: small animals of the streambed, ranging from 1.5 to 40
thousandths of an inch.
Membrane: a thin, pliable layer of tissue that covers surfaces, or
separates, or connects regions, structures, or organs of an animal or
plant
Mesotrophic: middle range of productivity; between oligotrophic and
eutrophic.
Metabolism: the complex of physical and chemical processes involved
in the maintenance of life
Metabolite: any of various organic compounds produced by metabolism
Metamorphic: of or relating to metamorphosis; in geology, a rock that
has been changed by metamorphism
Metamorphosis: change is size or form at molting of an insect or
crustacean
Microcrustaceans: small crustaceans, consisting of ostracods,
copepods, and cladocerans.
Microfauna: assemblage of very small animals.
Microinvertebrate: very small invertebrate too tiny to see without
magnification (See also meiofauna)
Micron: one-millionth of a meter, about 1/25,000 of an inch.
Microtopography: the features of a small place or region, such as one
square foot, as opposed to the features of a large place or region, such
as one square mile
Mineral soil: soil composed mainly of inorganic materials and with a
relatively low amount of organic material
Mineralization: breakdown of a chemical compound into lesser
compounds or elements.
Mollusk: any member of the phylum Mollusca, of largely marine
invertebrates, including the edible shellfish, such as clams, and some
100,000 other species
Monoecious: term applied to a plant having both male and female
reproductive organs; see hermaphroditic.
Montane: moist, cool upland slopes (below timberline) dominated by
coniferous trees.
Multilayered: a forest canopy with two or more distinct layers of trees
Multivoltine: having several generations per year.
Mycelium (pl. Mycelia): the vegetative part of a fungus, consisting
of a mass of branching threadlike filaments or strands called hyphae
Mycorrhiza: the symbiotic relationship of a fungus with the roots of
certain plants
Naiad: older use for the immature stage in certain insect orders;
now: nymph.
Natural history: science of distribution, behavior, and taxonomy of
organisms; see ecology.
Nauplius: juvenile form of copepods.
Nekton: group of aquatic organisms capable of swimming; compare
plankton.
Neuston: group of aquatic animals occurring in the surface film of
water; see nekton, plankton.
Nitrification: process of transforming ammonium nitrogen into
nitrate.
Nitrogen fixation: the conversion of elemental nitrogen (N) from the
atmosphere to organic combinations or to forms readily usable in
biological processes
Nitrogen-fixing bacteria: bacteria that can take nitrogen gas out of
the air and transform it into an organic compound that plants can use
Nocturnal: to be active during the hours of darkness
Null point: that point in an estuary where the velocity of the
downstream flow of less dense, less saline water near the surface of the
channel and the upstream flow of more dense, more saline water near the
bottom of the channel meet and effectively cancel one another out
Nutrient spiraling: pattern of nutrient movement downstream, into and
out of various forms.
Nymph: immature stage of hemimetabolous insects.
Obligate: an organism that is able to survive only in a specific type
of environment or only in a specific type of relationship within a
variety of environments
Oligotrophic: referring to low level of productivity.
Organic: of, pertaining to, or derived from living organisms; of or
designating compounds containing the element carbon; contrast Inorganic
Organic combinations: mixtures of organic substances
Overflow channel: a channel that is created and used by a stream when
it is overflowing its banks during a flood
Oviposition: act of laying eggs, usually referring to insects.
Ovoviviparous: term applied to animals wherein the females produce
eggs, retain them unto hatching, and then release the living young;
compare viviparous.
P:B: production/biomass ratio.
Patch of an ecosystem: The term patch dynamics is used regularly in
the newly developing fields of landscape ecology and conservation
biology, but it has been used previously as a standard ecological term.
Use of the term patch recognizes that most eco- systems are not
homogeneous, but rather a group of patches or ecological islands that
are recognizably different from the parts of the ecosystem that surround
them but nevertheless interact with them.
Periphyton: form of algae and other organisms on stones and other
substrates on the streambed, the principal food of many benthic insects
and other invertebrates.
Phytoplankton: plant organisms, generally microscopic, that float or
drift in great numbers in fresh or salt water
Piercer: functional group whose members are equipped with a piercing
organ used to penetrate the tissues of other organisms for feeding; some
herbivorous, some predaceous.
Piezometer: shallow-well for measuring groundwater-surface water
interactions.
Piling: a log driven into the bottom of a stream, river, or estuary
to support a structure or to use as a mooring for such things as rafts
of logs
Plankton: plant and animal organisms, generally microscopic, that
float or drift in great numbers in fresh or salt water
Plastron: envelope of air that some air-breathing insects use for
respiration under water.
Polytypic species: species of animal with many genetic types or
stocks, known for many salmonids.
Potamodromous: referring to fish species that migrate solely between
portions of streams.
Potamodromy: life history feature of migrating for spawning only in
rivers.
Potamon: lower section of rivers where currents are slow, water
temperatures high, and the fish fauna of warmwater species; compare
rhithron.
Predator: any animal that kills and feeds on other animals
Primary production: process of elaborating plant tissue; see
photosynthesis.
Production: biomass ratio: P:B; the relationship between production
rate and biomass; turnover ratio.
Progradation: the process of building upward and outward of land
through the deposition of sediments that result from disturbances to the
stability of the upslope water catchments, which increases the amount of
sediments that are carried down the streams and rivers and thereby
increases the amount of sediments that are deposited in a given locale
in the lowlands
Pupa (pl. Pupae): the stage between the larva and the adult in
insects with complete metamorphosis; it is a non-feeding and usually
outwardly inactive stage
Pupate: to transform to a pupa
Rapid: an extremely fast-moving part of a river, caused by a steep
descent in the riverbed
RCC: river continuum concept.
Reach of stream: a stretch of water that is geomorphically defined,
such as between bends in a stream, river, or channel or between the
start of a meadow or canyon
Recharge area: part of a catchment where precipitation filters into
the ground; compare discharge area.
Recruitment: juvenile individuals of a given species entering a
population for the first time
Redd: spawning nest of trout and salmon.
Refractory: resistant to decomposition.
Reset: return to downstream succession below a dam.
Retreat: chamber constructed of small stones and sand by members of
the caddisfly family Hydropsychidae, in which the larva lives and gleans
food particles from its capture net.
Rheogenesis: origin of a stream or river.
Rhithron: upper portion of a stream where currents are swift, water
temperatures are low, streambeds are composed of stones and gravel, and
the fish fauna often includes salmonids; compare potamon.
Riffle: a stretch of choppy water caused by a shoal or sandbar lying
just below the surface of a waterway
Riparian forest: forest stands that extend laterally from the active
channel to include the active floodplain, adjacent wetlands, etc. that
contribute organic matter, LWD on floodplain and channel
surfaces.
Riparian vegetation: Hydrophytic vegetation growing in the immediate
vicinity of a lake or river close enough so that its annual
evapotranspiration represents a factor in the lake or river regime.
Riparian zone: The border or banks of a stream. Although this term is
sometimes used interchangeably with floodplain, the riparian zone is
generally regarded as relatively narrow compared to a floodplain. The
duration of flooding is generally much shorter, and the timing less
predictable, in a riparian zone than in a river floodplain.
River Continuum Concept (RCC): The idea that a continuous gradient of
physical conditions exists from headwaters to mouths of rivers, and that
structural and functional characteristics of biological communities are
adapted to conform to the most probable position or mean state of the
physical system. Producer and consumer communities establish themselves
in harmony with the dynamic physical conditions of a given reach, and
downstream communities are fashioned to capitalize on the inefficiencies
of upstream procession of organic matter. Both upstream inefficiency
(leakage) and downstream adjustment seem predictable.
Riverine wetlands: Wetland systems of less than 0.5 ppm ocean salts,
exposed to channelized flow regimes. Riverine wetlands are categorized
according to flow regimes such as tidal waters, slow-moving waters with
well-developed floodplains, fast-moving waters with little floodplain,
and intermittent systems.
Riverine: of the river
Runoff: water from precipitation as it flows over land toward a
stream.
Salmonid: a fish of the family salmonidae, which includes trout and
salmon
Salter: anadromous brook trout that spawns in freshwater streams and
migrates to the ocean for growth.
Saprophyte: a plant that lives on and derives its nourishment from
dead or decaying organic matter
Scraper: functional group equipped with an organ to scrape surfaces
for periphyton or biofilm; see grazer.
Second-order stream: see Stream order
Sediment: inorganic particles deposited on the streambed, ranging in
size from clay to boulders.
Semelparous: reproducing only once during a life cycle.
Semiaquatic: adapted for living or growing in or near water; not
entirely aquatic
Semiterrestrial: adapted for living or growing on or near land; not
entirely terrestrial
Semivoltine: one generation living for two or three years.
Serial discontinuity concept: The idea that dams shift the physical
and biological characteristics of streams and rivers away from the
pattern predicted by the river continuum concept. A dam may make
conditions more like those of the headwaters (an upstream shift) or more
like those downstream, or it may have a negligible effect. Multiple dams
create multiple discontinuities in the expected or natural pattern of
streams and rivers.
Seston: small particles of drifting organic matter.
Shredder: functional group of invertebrates that chew up pieces of CPOM.
Side channel: a channel that extends off the main channel of a stream
but remains connected to it, such as the backwater of an overflow
channel or of a cut-off meander
Silt: a sedimentary material consisting of fine mineral particles
intermediate in size between sand and clay
Slash: a collective term used for the roots, branches, tops of the
trees, and other unmerchantable fragments that are left on the site
after the trees have been cut down and the desirable pieces/logs have
been removed
Slope: the incline of the land surface measured in degrees from the
horizontal; also characterized by the compass direction it faces
Slough: a stagnant swamp, marsh, bog, or pond, especially as part of
a backwater, inlet, or bayou
Smolt: life cycle stage of migratory fish, particularly salmonids,
when they approach leaving their natal stream for the ocean.
Snag habitat: twigs, branches, and trunks of trees and bushes that
fall into a stream, providing habitat for insects that cling to the
structures.
Spatial heterogeneity: Variation in the attributes of an environment
over space.
Splake: hybrid between lake trout and brook (speckled) trout.
Splash dam: a small, wooden dam that temporarily retains water that
can be released at will to raise the level of the water in a stream's
channel to float logs to a larger river
Spring wood: young, usually soft, fast-growing wood with large cells
that lies directly beneath the bark and develops in early spring when
there is ample moisture; spring wood can be seen in the stump of a tree
as the lighter, larger rings in the wood, as opposed to the summer wood,
which is represented by the smaller, darker rings in the wood
Standing stock: see biomass.
Stem: the principal axis of a plant from which buds and shoots
develop; with woody species, the term applies to principal axes, or
trunks, of all ages and thicknesses
Stenothermic: term applied to fish and other animals that prefer a
narrow range of temperatures, often salmonids; compare eurythermic.
Stream buffer: A variable-width strip of vegetated land adjacent to a
stream that is preserved from development activity to protect water
quality and aquatic and terrestrial habitats.
Stream order: Rivers and streams are classified by order. The order
of a river or stream is a dimensionless number that indicates how many
tributaries it has. The smallest unbranched tributary in a watershed is
designated order 1. A channel formed by the confluence of two such
tributaries is designated order 2. Where 2 order tributaries join, a
channel segment of order 3 is formed, and so on. In general, the higher
the order number, the larger is the watershed, and the greater are the
channel dimensions and discharge.
Structure: objects on the streambed that support periphyton and
biofilms, cover, and attachment sites for invertebrates, such as stones,
woody debris, and macrophytes.
Subimago: life cycle stage of mayflies, a flying, immature form
preceding the flying adult.
Succession: sequential changes in vegetation, invertebrates, and fish
downstream through the course of a stream.
Summer wood: wood that develops during the latter part of the growing
season when the supply of water is not so ample as in spring and
therefore has smaller cells, which in turn makes it darker, harder, and
less porous than spring wood; summer wood can be seen in the stump of a
tree as the darker, smaller rings in the wood, as opposed to the spring
wood, which is represented by the larger, lighter rings in the wood
Suspended sediments: sediments that are suspended in and by the water
in which they are carried and in which they may be kept from settling
out by the motion or velocity of the water in which they are suspended
Sympatry: when populations of two species occur together.
Synchrony: referring to the occurrence of each of a species' life
cycle events occurring over a short period of time.
Tannin (tannic acid): any of various chemically different substances
capable of promoting the tanning of leather
Taxon: unit of taxonomy, such as phylum, order, species, etc.
Terrace: a raised bank of earth that has vertical or sloping sides
and a flat top; a flat, narrow stretch of ground that has a steep slope
facing a river
Terrestrial: associated with the land
Third-order stream: see Stream order
Trivoltine: with three generations, or cohorts, per year.
Trophic level: group of organisms with common feeding behavior.
Trophic pyramid: graphic representation of pyramid-shaped structure
of successive trophic levels.
Unconfined aquifer: aquifer located only above an impermeable rock
stratum.
Underfit river: small river flowing through a large valley.
Univoltine: with one cohort per year.
Upwelling: the movement of cold water up from the bottom to mix with
the warmer water at the surface
Vascular plant: any plant that contains vessels
Vertebrate: an animal with a backbone
Vertical Height Gradient (VHG): measure for quantifying hyporheic
exchange (unitless value; if positive = upwelling, if negative =
downwelling)
Voltinism: expressing number of cohorts per year.
Warmwater: term roughly defining stream with warmwater fish species.
Water catchment: a drainage basin that catches water; either rain,
snow, or both, and stores it in a slow-motion downward flow as it merges
with ever-larger water catchments until it is finally accepted into the
sea
Water column: the vertical space of water that exists between the
bottom and the surface of a body of water, such as a stream or lake
Water table: the surface in a permeable body of rock of a zone
saturated with water
Watershed scale approach: A consideration of, the entire watershed,
including the land mass that drains into the aquatic ecosystem.
Watershed: The entire surface drainage area that contributes water to
a lake or river.
Wetlands: Term for a broad group of wet habitats. Wetlands are lands
transitional between terrestrial and aquatic systems where the water
table is usually at or near the surface or the land is covered by
shallow water. Wetlands include features that are permanently wet, or
intermittently water covered, such as swamps, marshes, bogs, muskegs,
potholes, swales, glades, slashes, and overflow land of river valleys.
According to the 1989 federal wetlands delineation manual, wetlands
include lands saturated for at least 7 days to a depth of 12 inches. A
newly proposed definition by the Bush Administration would be lands that
have 15 days of standing water and 21 days of surface saturation.
Xylophage: organism feeding on wood.
Xylophagid: the vernacular for the generic name Xylophaga
Year class: cohort of fish, named by year of hatching.
Zero Order: headwater region of stream consisting of small spring
seeps; that is, above First Order.
TOP
|
Printable
Version