ATV (All-Terrain Vehicle) Small, motorized 3-or 4-wheeled vehicles specifically designed for off-road use. The American National Standards Institute (ANSI) further defines an ATV as a vehicle that travels on low-pressure tires, with a seat that is straddled by the operator, and with handlebars for steering control. By the current ANSI definition, it is intended for use by a single operator, although a change to include 2-seaters (in tandem) is under consideration. Herein, the definition of ATV coincides with the description above and does not include passenger vehicles, including sport-utility vehicles or 4-wheel-drive jeeps. fugitive dust Dust raised by mechanical (anthropogenic) disturbance of granular material exposed to and becoming suspended in the air, then carried by wind. Arises from "nonpoint" sources-such as unpaved roads, agricultural tilling operations, aggregate storage piles, and heavy construction-rather than "point" sources-such as confined flow streams discharged to the atmosphere from a stack, vent, or pipe. indicator threshold For a given land health indicator (or set of indicators), the value(s) at or above which management action may be triggered or required. land health The condition of natural resource attributes, including soils and site stability, hydrologic function, and biotic integrity. OHV Defined herein as any civilian off-highway vehicle, including motorcycles, motorized dirt bikes, ATVs (see definition above), snowmobiles, dune buggies, 4-wheel-drive jeeps, sport-utility vehicles, and any other civilian vehicles capable of off-highway, terrestrial travel (including utility vehicles [UTVs] and ATVs with more than 4 wheels). OHV route Defined herein as any unpaved route created for OHV travel, including single-track paths or trails, two-tracks, and unimproved or improved dirt/gravel roads. Herein, this term is also applied to "rogue" (undesignated or unauthorized) routes created by OHV users in closed or limited areas. population dynamics Herein, used broadly to include wildlife or vegetation population size, density, and/or distribution (both spatial and temporal); rates of birth/germination, death, and/or survivorship; population gender/age-class structure; population genetics; and/or the rates/directions of change in all these parameters. right-of-way habitat Habitat provided within the legal description of a given transportation corridor. sink population For a given metapopulation, a population sink is a local area or habitat where the local population's reproductive rate is lower than the required replacement rate (in other words, a sink population is eventually extirpated without immigration of individuals from other areas). Population sinks often occur where there is excessive predation pressure and/or poor habitat quality. source population For a given metapopulation, a population source is a local area or habitat where the local population's reproductive rate is greater than the required replacement rate. Excess individuals produced from a source population may emigrate to j...
