ABIOTIC - Not biotic or not living; often referring to the nonliving components of the ecosystem such as soils, water, and climate.

 

ACID RAIN - A complex chemical and atmospheric phenomenon that occurs when emissions of sulfur and nitrogen compounds and other substances are transformed by chemical processes in the atmosphere, often far from the original sources, and then deposited on earth in either a wet or dry form.

 

ACTION - A desired outcome.  For example, a major construction project.

 

ACTION - (ESA§) All activities or programs of any kind authorized, funded, or carried out, in whole or in part, by Federal agencies in the United States or upon the high seas [50 CFR §402.02].

 

ACTION AREA - (ESA§)  All areas to be affected directly or indirectly by the Federal action and not merely the immediate area involved in the action [50 CFR §402.02].

 

ADAPTION - The result of a process usually involving long-term evolutionary adjustment of a population to environmental changes.

 

ADAPTIVE MANAGEMENT - (1) The process of implementing policy decisions as scientifically driven management experiments that test predictions and assumptions in management plans; and using the resulting information to improve the plans; (2) A mechanism for integrating scientific knowledge and experience for the purpose of understanding and managing natural systems.

 

ADVISORY COUNCIL - (NHPA§) Advisory Council on Historic Preservation (ACHP) or Council.  The ACHP, an independent Federal agency composed of 19 members, is charged with advising the President and the Congress on historic preservation matters and administering the provisions of Section 106 of the National Historic Preservation Act.  The various duties of the Council that are defined by regulations at 36 CFR Part 800 are carried out by Council members, the Council Chairman, and the Council Executive Director, according to an internal delegation of authority.

 

AESTHETIC ATTRIBUTES - Perceptual stimuli that provide diverse and pleasant surroundings for human enjoyment and appreciation.  Included in this category are sights, sounds, scents, tastes, and tactile impressions, and the interactions of these sensations, of natural and cultural resources.  Examples are the sight of a pristine landscape, the view of a historic fortress, the sound of a waterfall or brook, the scent of a hedgerow of honeysuckle or a pine forest, and the taste of mineral water.

 

AESTHETIC QUALITY - The distinctive property of a landscape determined by professional, public, or personal values and the intrinsic physical properties of the landscape.

 

AESTHETIC RESOURCE - Those natural man-made features of the environment which can be perceived by the senses.  That is, what is seen and what is perceived by the other senses.  Aesthetic resources elicit one or more sensory reactions and evaluations by the observer, particularly in regards to their pleasurable effects.  Aesthetic resources include the combination of what can be perceived at a particular site.  This involves the unified combination of water resources, landform, vegetation, and user characteristics at a site.  An aesthetic resource may be a particular landscape, viewshed, or view.

 

AFFECTED INTERESTS - Those persons and organizations impacted by the proposed action, either directly or indirectly.  These impacts include economic, recreational, or lifestyle changes and changes to the physical or biological environment (e.g., hydrology, vegetation, or wildlife).

 

AFFECTING - (NEPA§) Will or may have an effect on [40 CFR §1508.3].

 

AICUZ - Air Installation Compatible Use Zone.  A process for predicting the impact of an air program on the surrounding area, involving the measurement of various noise levels.

 

ALLEE EFFECT - The phenomenon of a population dropping below a threshold density or number of individuals from which it cannot recover; named after the animal ecologist W.C. Allee.

 

ALLELE - One of a pair of genes at a particular genetic locus.

 

ALLUVIUM - A general term for clay, silt, sand, gravel, or similar unconsolidated detrital material deposited during comparatively recent geologic time by a stream or other body of running water as a sorted or semisorted sediment in the bed of the stream.

 

ALPHA DIVERSITY- Species diversity within a habitat.

 

ALTERNATIVE COURSES OF ACTION - (ESA§) All alternatives and thus is not limited to original project objectives and agency jurisdiction.

 

ALTERNATIVES - (NEPA§) Methods of accomplishing the proposed action, with each alternative at least partially satisfying the desired outcome [40 CFR §1502.14 and 1508.25 (b)].

 

AMBIENT MONITORING ‑ Monitoring within natural systems (e.g., lakes, rivers, estuaries, wetlands) to determine existing conditions.

 

ANCIENT FOREST - Forest in late successional stages, or a shifting mosaic of forest patches in various ages after natural disturbances.

 

ANADROMOUS FISH - (ESA§) Fish that spend most of their lives in salt water but migrate into fresh water to spawn, e.g., salmon, shad, and striped bass.

 

ANTICIPATORY DEMOLITION - (NHPA§) An action of an applicant who, with intent to avoid the requirements of NHPA§ 106, has intentionally significantly adversely affected a historic property to which an agency grant of a loan, loan guarantee, permit, license, or other assistance relates, or an inaction of an applicant who, having the legal power to prevent it, allowed such a significant adverse effect to occur.

 

APPLICANT - (ESA§) Any person (an individual, corporation, partnership, trust, association, or any other private entity; or any officer, employee, agent, department, or instrumentality of the Federal Government, of any State, municipality, or political subdivision of a State, or of any foreign government; any State, municipality, or political subdivision of a State; or any other entity subject to the jurisdiction of the United States) who requires formal approval or authorization from the Service as a prerequisite to conducting the action [50 CFR §402.02].

 

APPROVAL OF THE EXPENDITURE OF FUNDS - (NHPA§) Any final agency decision approving the eligibility of an undertaking for Federal funds or financial assistance, including any agency decision that may be subject to an administrative appeal or rehearing procedure and conditional decisions subject to reevaluation by the agency.

 

AQUIFER - An underground bed or layer of earth, gravel, or porous stone that contains water that typically is capable of yielding a significant amount of water.

 

AREA/PERIMETER RATIO - The ratio of internal area to edge habitat of a region.  The area/perimeter ratio is an indication of the amount of interior habitat with respect to edge habitat, and may indicate potential success of a reserve in protecting interior species.

 

ARCHAEOLOGICAL RESOURCE - Any material remains of past life or activities which are of archeological interest [16 USC §470bb].

 

ARCHAEOLOGICAL SITE - Any location containing evidence such as artifacts or features.

 

ARCHITECTURAL RESOURCES - Structures, landscaping, or other human constructions that possess artistic merit, and particularly representative of their class or period, or represent achievements in architecture, engineering, technology, design or scientific research and development; such resources may be important for their archaeological or historical value as well.

 

AREA OF POTENTIAL EFFECTS - (NHPA§) The geographic area or areas within which an undertaking may directly or indirectly cause changes, whether beneficial or adverse, to the character or use of historic properties, if any such properties exist. The area of potential effects is not limited to land under Federal jurisdiction or control or land within a Federal construction, right‑of‑way, or permit area.

 

ARTIFACT - In the broadest sense, any product or by-product of human activity.

 

ARTIFICIAL RECHARGE - Replenishment of the groundwater supply by means of spreading basins, recharge wells, irrigation, or induced infiltration of surface water.

 

ASSEMBLAGE - A given taxonomic subset of a larger community (e.g., a bird assemblage in a deciduous forest).

 

ASSIMILATIVE CAPACITY - The capacity of a natural body of water to receive:  (1) water, without deleterious effects, (2) humans who consume the water, and (3) BOD, within prescribed dissolved oxygen limits.

 

ASSOCIATED FUNERARY OBJECTS - Objects that, as a part of the death rite or ceremony of a culture, are reasonably believed to have been placed with individual human remains either at the time of death or later, and both the human remains and associated funerary objects are presently in the possession or control of a Federal agency or museum, except for other items exclusively made for burial purposes or to contain human remains shall be considered as associated funerary objects [PL 101-601 §2].

 

ASSOCIATED RECORDS - Original records (or copies thereof) that are prepared assembled and document efforts to locate, evaluate, record, study, preserve, or recover a prehistoric or historic resource [36 CFR §79.4].

 

ASSOCIATION - A definite or characteristic assemblage of plants and animals living together in an area essentially uniform in environmental conditions; any ecological unit of more than one species.

 

AUTECOLOGY - The study of the ecology of a single species.

 

BACKGROUND EXTINCTION RATE - Historical rates of extinction due to environmental causes not influenced by human activities, such as the rate of species going extinct because of long-term climate change.

 

BANK STORAGE - Water entering the banks of stream channels during high stages of stream flow, most of which returns to stream flow during falling stages.

 

BASELINE DATA - Environmentally related information collected from a site, either undisturbed or disturbed.  Baseline data are collected to provide a reference point to which future changes in the environment resulting from an action can be compared. 

 

BASE RUNOFF - Sustained or fair weather runoff.  In most streams, base runoff is composed largely of groundwater effluent.

 

BEAUTIFICATION - Improvement of project lands for the primary purpose of aesthetic quality, usually involving landscaping, restoring construction scars, etc.

 

BED LOAD - Course material moving on or near the bed of a flowing stream.

 

BENCHMARK AREAS - Areas of natural or minimally disturbed habitat that can serve as control or comparison areas to measure the effects of an activity or management practice on similar habitat in the same region.

 

BENTHOS - Those organisms which live on the bottom of a body of water.

 

BETA DIVERSITY - Species diversity between habitats or along an environmental gradient.

 

BIODIVERSITY - See BIOLOGICAL DIVERSITY.

 

BIOLOGICAL ASSESSMENT - (ESA§) Information prepared by or under the direction of a Federal agency using the procedures in 50 CFR §402.12 concerning listed and proposed species and designated and proposed critical habitat that may be present in the action area and the evaluation of potential effects of the action on such species and habitat.

 

BIOLOGICAL DIVERSITY - The variety of genetic combinations, species functions and associations, both biotic and abiotic, occurring in an area, and typically with the degree representative of the indigenous flora and fauna as a benchmark.  Biological diversity does not simply equal species richness as defined here. 

 

BIOLOGICAL OPINION - (ESA§) Document stating the opinion of the Fish and Wildlife Service or the National Marine Fisheries Service on whether or not a Fish and Wildlife Service action is likely to jeopardize the continued existence of listed species, or result in the destruction or adverse modification of critical habitat [50 CFR §402.02].

 

BIOMASS - The total weight of matter incorporated into (living and dead) organisms.

 

BIOME - Any of the major terrestrial ecosystems of the world such as tundra, deciduous forest, desert, taiga.

 

BIOPHILIA - A term coined by E.O. Wilson to describe humans' seemingly innate, positive attitudes about, and love for, nature and natural diversity.

 

BIOTA - All of the organisms, including animals, plants, fungi, and microorganisms, found in a given area. 

 

BIOTIC - Pertaining to any aspect of life.

 

BUILDING - A structure created to shelter any form of human activity, such as a house, barn, church, hotel, or similar structure.  Building may refer to a historically related complex such as a courthouse and jail, or a house and barn [36 CFR §60.3].

 

BURIAL SITE - Any natural or prepared physical location, whether originally below, on, or above the surface of the earth, into which as a part of the death rite or ceremony of a culture, individual human remains are deposited [PL 101-601 §2].

 

CANDIDATE SPECIES - (ESA§)  Under the 1996 revised listing policy, candidate species are species for which the Fish and Wildlife Service has enough scientific information to warrant proposing them for listing as endangered or threatened under the Endangered Species Act.  Only those species for which there is enough information to support a listing proposal will be called "candidates."  These species were formerly known as "Category 1 Candidate Species."

 

PRE 1996 CANDIDATE SPECIES definitions - Any species being considered by the Secretary of the Interior for listing as an endangered or threatened species [50 CFR §424.02].

 

Category 1 - Taxa for which substantial information exists to support proposal to list the taxon as endangered or threatened.

 

Category 2 - Taxa for which information exists to support proposal to list the taxon as endangered or threatened, but for which conclusive data on biological vulnerability and threat are not currently available to support proposed rules.

 

Category 3 - Taxa that were once being considered for listing as endangered or threatened, but are not currently receiving such consideration.

 

Subcategory 3A - Taxa for which persuasive evidence of extinction is available.  If rediscovered, such taxa might warrant high priority for addition to the List of Endangered and Threatened Wildlife.

 

Subcategory 3B - Taxonomic names that, on the basis of current taxonomic understanding, usually as represented in published revisions and monographs, do not represent taxa meeting the legal definition of species in the Endangered Species Act.  Future investigation could lead to re-evaluation of the listing qualifications of such entities.

 

Subcategory 3C - Taxa that are now considered to be more abundant and/or widespread than previously thought.  Should new information suggest that any such taxon is experiencing a numerical or distributional decline, or is under a substantial threat, it may be considered for transfer to Category 1 or 2.

 

CARRYING CAPACITY - (Biological) The maximum population size of a given species in an area beyond which no significant increase can occur without damage occurring to the area and to the species.

 

CARRYING CAPACITY - (Training or outdoor recreation) The maximum amount of training or recreation activity and number of participants that a land or water area can support in a manner compatible with the objectives of the natural resources management plan without degrading existing natural resources.

 

CATEGORICAL EXCLUSION - (NEPA§) "Categorical Exclusion" means a category of actions which do not individually or cumulatively have a significant effect on the human environment and which have been found to have no such effect in procedures adopted by a Federal agency in implementation of these regulations [40 CFR §1507.3) and for which, therefore, neither an environmental assessment nor an environmental impact statement is required.  An agency may decide in its procedures or otherwise, to prepare environmental assessments for the reasons stated in 40 CFR §1508.9 even though it is not required to do so.  Any procedures under this section shall provide for extraordinary circumstances in which a normally excluded action may have significant environmental effect [40 CFR §1508.4].

 

CHANNEL IMPROVEMENT - The improvement of the flow characteristics of a channel by clearing, excavation, realignment, lining, or other means in order to increase its capacity; sometimes used to connote channel stabilization.

 

CHANNEL STABILIZATION - Erosion prevention and stabilization of velocity distribution in a channel using jetties, drops, revetments, vegetation, and other measures.

 

CHANNELIZATION - To straighten and deepen streams so water will move faster, a flood reduction or marsh drainage tactic that can interfere with waste assimilation capacity and disturb fish habitat.

 

CIRQUE - A deep steep-walled half-bowl-like recess or hollow situated high on the side of a mountain and commonly at the head of a glacial valley, and produced by the erosive activity of a mountain glacier [Bates and Jackson, 1980].

 

CLIMAX - The theoretical culminating stage in the succession of a natural community at a given site, at which the community is self-reproducing and thus has reached a stable State.

 

CLIMAX COMMUNITY - The final, stable community in an ecological succession which is able to reproduce itself indefinitely under existing conditions.

 

CLONE - A population of individuals all derived asexually from the same single parent.

 

CO-ADAPTED GENE COMPLEXES - A concept in which particular gene combinations, presumably acting in concert through a long association, function particularly well together.

 

COARSE FILTER - Biological inventory and land protection approach that focuses on communities, ecosystems, habitats, or landscapes.

 

COASTAL ZONE - The coastal waters (including lands therein and thereunder) and the adjacent shorelands (including the waters therein and thereunder) strongly influenced by each other and in proximity to the shoreline of the several coastal states.  Includes islands, transitional and intertidal areas, salt marshes, wetlands, and beaches [PL 92-583].

 

COLD-DECIDUOUS BROADLEAF - Woody angiosperms with wide, flat leaves (e.g., paper birch) that are shed by plants during the dormant season (that portion of the year when frosts occur).

 

COLLUVIUM - A general term applied to any loose, heterogeneous, and incoherent mass of soil material and/or rock fragments deposited by rainwash, sheetwash, or slow continuous downslope creep, usually collecting at the base of gentle slopes or hillsides [Bates and Jackson, 1980].

 

COLONIZATION - The immigration of a species into a new habitat and the founding of a new population.

 

COMMENT - (NHPA§) The findings and recommendations of the Council membership formally provided in writing to the head of a Federal agency under §106.

 

COMMERCIAL ACTIVITY - (ESA§) All activities of industry and trade, including, but not limited to, the buying or selling of commodities and activities conducted for the purpose of facilitating such buying and selling; however, it does not include exhibitions of commodities by museums or similar cultural or historical organizations.

 

COMMUNITY - All of the plants, animals, and microbes in an area or volume; a complex association usually containing both animals and plants.

 

CONDITIONAL NO ADVERSE EFFECT AGREEMENT - (NHPA§) An agreement between an Agency Official and a State Historic Preservation Officer that an undertaking will have no adverse effect because the undertaking is being conducted in accordance with specified conditions.

 

CONFERENCE - (ESA§) A form of intra-agency cooperation involving discussions within the Service pursuant to section 7(a)(4) of the ESA.  Conferences are required for Service actions likely to jeopardize species proposed for listing or category I candidates, or likely to adversely modify proposed critical habitat.  Such conferences are designed to help the Service identify and resolve potential conflicts between an action and species conservation early in a project's planning.  They should identity recommendations to minimize or avoid adverse effects [50 CFR §402.02, §402.10].

 

CONSERVE/CONSERVATION - (ESA§) To use/the use of all methods and procedures to bring any endangered species or threatened species to the point at which the measures provided pursuant to the ESA are no longer necessary.

 

CONSERVATION - The protection, improvement, and use of natural resources according to principles that will provide optimum public benefit.

 

CONSERVATION - (ESA§) The terms "conserve," "conserving," and "conservation" mean to use, or the use of, all methods and procedures necessary to restore a listed species to the point at which ESA protection no longer is necessary.  These methods and procedures include, but are not limited to, all activities associated with scientific resources management.  Examples of such activities are research, census, law enforcement, habitat acquisition and maintenance, propagation, live trapping, and transportation, and—in the extraordinary case where population pressures within a given ecosystem cannot otherwise be relieved—regulated taking [ESA §3(3)].

 

CONSERVATION BIOLOGY - An integrative approach to the protection and management of biological diversity that uses appropriate principles and experiences from basic biological fields such as genetics and ecology, from natural resource management fields such as fisheries and wildlife, and from social sciences such as anthropology, sociology, philosophy, and economics.

 

CONSERVATION RECOMMENDATIONS - (ESA§) Suggestions resulting from formal or informal consultation that (1) identify discretionary measures the Service can take to minimize or avoid the adverse effects of a proposed action on listed species or critical habitat; (2) identify studies, monitoring, or research to develop new information on listed species or critical habitat; and (3) include suggestions on how the Service can assist species conservation, in association with the project, under the authority of section 7(a)(1) of ESA [50 CFR §402.02].

 

CONSULTATION - (NHPA§) The good faith process of seeking, discussing, and considering the views of other participants in the §106 process as set forth in §800.1(b).  Consultation is required per the NHPA, 36 CFR 800, and/or a MOA or CRMP.

 

CONSTITUENT ELEMENTS - (ESA§) Physical and biological features of critical habitat including, but not limited to: (1) space for individual and population growth, and for normal behavior; (2) food, water, air, light, minerals, or other nutritional or physiological requirements; (3) cover or shelter; (4) sites for breeding, reproduction, rearing of offspring, germination, or seed dispersal; and generally, (5) habitats that are protected from disturbance or are representative of the historic geographic and ecological distributions of a species [50 CFR 424.12(b)].

 

CONSUMER - An organism that consumes another.

 

CONSUMER (PRIMARY) - An organism which consumes green plants.

 

CONSUMER (SECONDARY) - An organism which consumes a primary consumer.

 

CONTRIBUTING PROPERTY - (NHPA§) A property in a historic district which adds to the historic architectural qualities, historic associations, or archeological values for which a property is significant because it was present during the period of significance, and time or is capable of yielding important information about a period, or it independently meets the National Register criteria.

 

COOPERATING AGENCY - (NEPA§) Any Federal agency other than a lead agency with jurisdiction by law or special expertise with respect to any environmental impact involved in a proposal, legislation, or other Federal action that significantly affects the quality of the human environment  [40 CFR §1508.5].

 

CORRIDOR - A route that allows movement of individuals or taxa from one region or place to another.

 

COUNCIL MEMBERSHIP - (NHPA§) The full membership of the Council or a subgroup of members, numbering not less than three, appointed by the Chairman to carry out specific responsibilities under this part.

 

COUNCIL ON ENVIRONMENTAL QUALITY (CEQ) - The body charged with monitoring progress toward achieving the national environmental goals as set forth in NEPA.  The CEQ promulgates regulations governing the NEPA process for all Federal agencies.

 

CREATED WETLAND ‑ A wetland at a site where it did not formerly occur.  Created wetlands are designed to meet a variety of human benefits including, but not limited to, the treatment of water pollution discharges (e.g., municipal wastewater, stormwater) and the mitigation of wetland losses permitted under Section 404 of the Clean Water Act.  This term encompasses the term "constructed wetland" as used in some EPA guidance and documents.

 

CRITICAL ECOLOGICAL PROCESSES - The diversity and complexity of ecosystems seem to depend on a small set of biotic and abiotic, or physical processes, each operating over different scale ranges.  For example, ecological conditions at the scale of the patch in a forest may depend on natural fire cycles.

 

CRITICAL HABITAT - (ESA§) Specific areas within the geographic area commonly occupied by a species which contain features essential to the conservation of the species and which may require special management consideration or protection.  Specific areas outside of the currently occupied range of a threatened or endangered species may be determined by the Secretary of the Interior as areas essential for the conservation of the species [50 CFR §424.02].

 

CUESTA - A hill or ridge with a gentle slope on one side and a steep slope on the other; formed by uplifted rock outcrop consisting of strata having different resistance to erosion. [Bates and Jackson, 1980].

 

CULTURAL ATTRIBUTES - Evidence of past and present habitation that can be used to reconstruct or preserve human lifeways.  Included in this category are structures, sites, artifacts, environments, and other relevant information, and the contexts in which these occur.  Cultural attributes are found in archaeological remains of prehistoric and historic aboriginal occupations; historic European and American areas of occupation and activities; and objects and places related to the beliefs, practices, and products of existing folk or traditional communities and native American groups.  Examples are campsites of prehistoric mammoth hunters, a 19th century farmstead, and a stream crossing in long-standing use by an Appalachian community for baptizing church members.

 

CULTURAL HISTORY RESOURCE - Potential knowledge about human cultural systems, in the form of historic and prehistoric products and by-products of man.

 

CULTURAL RESOURCES - Refers to those tangible and intangible aspects of cultural systems, both living and dead, that are valued by or representative of a given culture or that contain information about a culture.  These resources are finite and nonrenewable and include, but are not limited to, sites, structures, districts, objects, and historic documents associated with or representative of peoples, cultures, and human activities and events either in the present or in the past.  Cultural resources can also include the primary written and verbal data for interpreting and understanding those tangible resources.

 

CULTURAL RESOURCES MANAGEMENT - An umbrella term for activities affecting cultural resources, including the preservation, conservation, use, protection, selective investigation of, or decision not to preserve, prehistoric and historic remains.  Cultural resources management specifically includes the development of ways and means, including legislation and actions to safeguard extant evidences or preserve records of the past.

 

CUMULATIVE EFFECTS - (ESA§) An analysis of those effects of future State, local, or private activities, not involving Federal activities, that are reasonably certain to occur within the action area of the Service action subject to consultation [50 CFR §402.02].

CUMULATIVE IMPACT - (NEPA§) "Cumulative impact" is the impact on the environment which results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency (Federal or non-Federal) or person undertakes such other actions [40 CFR §1508.7].  Cumulative impacts can result from individually minor but collectively significant actions taking place over a period of time.

 

DATA RECOVERY (ARCHAEOLOGICAL) - (a) Recovery and preservation (including long-term curation of a representative sample of archaeological and scientific data sufficient to address questions posed in the approved research design for the work, and the published analysis and interpretation of the meaning of such data in terms of the cultural sequence, settlement patterns, subsistence strategies and environmental conditions prevailing at the time(s) the project area was previously occupied or otherwise utilized by humans; (b) Recording, through architectural quality photographs and/or measured drawings of buildings, structures, districts, sites and objects, and deposition of such documentation in the Library of Congress as a part of the National Architectural and Engineering Record.

 

DECISION MAKER - Person who is responsible by regulation or position for making a given decision.

 

DEMOGRAPHIC BOTTLENECK - A significant, usually temporary, reduction in genetically effective population size, either from a population "crash" or a colonization event by a few founders.

 

DEMOGRAPHIC STOCHASTICITY - The effects of random events on the survival and reproduction of individuals. 

 

DENSITY STRATIFICATION - The arrangement of water masses into separate, distinct horizontal layers as a result of differences in density; may be caused by differences in temperature or dissolved and suspended solids.

 

DESTRUCTION or ADVERSE MODIFICATION - (ESA§) A direct or indirect alteration that appreciably diminishes the value of critical habitat for both the survival and recovery of a listed species [50 CFR §402.02].  Such alterations include, but are not limited to, alterations adversely modifying any of those physical or biological features that were the basis for determining the habitat to be critical.

 

DETERMINATION OF ELIGIBILITY - A decision by the Department of the Interior that a district, site, building, structure or object meets the National Register criteria for evaluation although the property is not formally listed in the National Register [36 CFR §60.3].

 

DESTRUCTION or ADVERSE MODIFICATION - A direct or indirect alteration that appreciably diminishes the value of critical habitat for both the survival and recovery of a listed species [50 CFR §402.02].

 

DISCOVERY - (NHPA§) To find a cultural resource in an unexpected location or of a class not covered by previous review under the NHPA, Section 106.

 

DISTRICT - (NHPA§) A geographically definable area, urban or rural, that possesses a significant concentration, linkage or continuity or sites, structures, buildings, or objects united by past events or aesthetically by plan or physical development.  A district may also compromise individual elements separated geographically but linked by association or history [36 CFR §60.3].

 

DIVERSITY - Ecological measure of number of species and their relative abundance (evenness) in a community; a low diversity refers to relatively fewer species or more uneven abundance, whereas a high diversity refers to a higher number of species or more even abundance.

 

DIVISION - An ecological unit in the ecoregion planning and analysis scale of the National Hierarchical Framework corresponding to subdivisions of a Domain that have the same regional climate.

 

DOCUMENTATION - (NHPA§) A documentary, photographic, and graphic record of a historic property.  Buildings and structures are documented according to the guidelines of NPS (HABS/HAER) for deposit in the Library of Congress.  Also includes documents associated with archeological effect.  See 36 CFR 800.

 

DOMAIN - An ecological unit in the ecoregion planning and analysis scale of the National Hierarchical Framework corresponding to subcontinental divisions of broad climatic similarity that are affected by latitude and global atmospheric conditions.

 

DOMINANCE - The degree of influence (usually inferred from the amount of area covered) that a species exerts over a community.

 

DRAFT EIS - First draft of an EIS circulated for comment from other agencies and the public.  It is prepared to satisfy, to the fullest extent possible, the requirements of a final statement [40CFR, §1502.9 (a)].

 

DREDGING - To remove earth from the bottom of water bodies.

 

DRUMLIN - An elongated hill or ridge of glacial drift.

 

DYNAMIC EQUILIBRIUM - A State of relative balance between forces or processes having opposite effects.

 

ECOLOGICAL ATTRIBUTES - Components of the environment and the interactions among all its living (including people) and non-living components that directly or indirectly sustain dynamic, diverse, viable ecosystems.  In this category are functional and structural aspects of the environment, including aspects that require special consideration because of their unusual characteristics.

 

ECOLOGY - The study of the interrelationships of organisms with and within their environment.

 

ECOLOGICAL SUCCESSION - The natural, sequential change of species composition of a community in a given area.

 

ECOREGION - (1) Regions of relative homogeneity with respect to ecological composition, structure, and function.  (2) A scale of planning and analysis in the National Hierarchical Framework that has broad applicability for modeling and sampling, strategic planning and assessment, and international planning.  Ecoregions include Domain, Division, and Province ecological units.

 

ECOSYSTEM - A dynamic complex of plant, animal, fungal, and microorganism communities and their associated abiotic environment interacting as an ecological unit.