Rangeland Management - Fire, Riparian Systems, Invasive Species, and IPM

Comprehensive vocabulary flashcards covering fire ecology, riparian dynamics, invasive plant mechanisms, classification, and integrated pest management (IPM) for NRSM 360 Exam II.

Wildfires

Uncontrolled and unplanned fires.

Fire Use (Let-Burn) Fires

Fires that are allowed to burn without active monitoring and are deemed unlikely to cause human harm.

Prescribed (Controlled) Fires

Planned and intentionally implemented fires used to accomplish specific land management objectives.

Fire Intensity

The rate at which a fire produces thermal energy, influenced by available fuel amount and composition, moisture, temperature, wind, and topography.

Fire Severity

The relative amount of alteration, disruption, or ecological damage a site experiences following a fire.

Fire Return Interval

The average period of time between fires occurring in a given area under a presumed historical regime.

Fire Triangle and Fire Behavior Triangle

Two models depicting fire needs: the Fire Triangle comprises the three components required for ignition and combustion (Oxygen, Heat, and Fuel), while the Fire Behavior Triangle comprises the three environmental drivers governing wildfire spread and behavior (Weather, Topography, and Fuel).

Twidwell et al. Fire Eras

A historical framework consisting of four fire eras: Coexistence era (indigenous burning), Suppression era (rapid wildfire suppression), Shadow era (localized prescribed burning), and Emerging wildfire era (current to future characterized by global change).

McNew et al. Fire Eras

A fire history framework comprising the Coexistence era (pre-Euro-American settlement indigenous fire stewardship and high pyrodiversity), Suppression era (suppression of fire-grazing interactions and heavy fuel accumulation), and Contemporary era (wildfire-driven management, prescribed burning, and fire education).

Patch Burn Grazing (Pyric Herbivory)

A management regime that combines rotational prescribed fire with livestock grazing across a single pasture system to generate a shifting mosaic of diverse vegetation structures and bird habitats.

Riparian Area

The transitional zone between water and land that receives water from overland runoff, subsurface flow, and groundwater recharge, making up approximately $1\text{--}2\%$ of land area in the western United States.

Sheet Erosion

A form of water erosion that removes a uniform thin layer of soil across broad top surface areas.

Rill Erosion

A type of shallow water channelization forming small channels that are less than $0.3\,\text{m}$ deep.

Gully Erosion

Severe water erosion forming deep channels greater than $0.3\,\text{m}$ deep that cause significant drops in the surrounding water table.

Cutbank

An unstable, eroding streambank formed along the outer curve of a meandering stream channel.

Headcut

An erosional break in slope occurring at the upstream extent of a channel or wet meadow that advances backwards (upstream) with ongoing erosion.

Channelization

The artificial straightening, deepening, or widening of a river, which disconnects it from its floodplain, increases water velocity, accelerates downcutting, and lowers the water table.

Beaver Dam Analogs (BDAs)

Man-made structures designed to mimic natural beaver dams in order to slow water velocity, trap sediment, and reconnect incised stream channels with their adjacent floodplains.

Invasive Species

An organism that is non-native (alien) to the ecosystem under consideration, whose introduction causes or is likely to cause economic harm, environmental harm, or harm to human health.

Disturbance Hypothesis

The theory proposing that disturbances such as fire, overgrazing, or drought create colonization opportunities for invasive species by reducing competition from resident native vegetation.

Enemy Release Hypothesis

The theory suggesting that non-native species proliferate because they escape the co-evolved natural enemies, herbivores, predators, and pathogens of their native range upon introduction to a new region.

Novel Weapons Hypothesis

The concept that certain invasive plants succeed by exuding inhibitory biochemicals (allelopathy) that are entirely new to native plant communities, suppressing competitors.

Tens Rule

An ecological rule of thumb stating that approximately $1$ in $10$ imported non-native species appear in the wild, $1$ in $10$ of those establish viable populations, and $1$ in $10$ of established species become invasive pests.

Biotic Resistance Hypothesis

The hypothesis that a resident community's native species richness and competition reduce the establishment success and spread rate of invading non-native species.

Montana Priority 1A Noxious Weeds

Plant species that are not present or have very limited presence in Montana, mandating immediate eradication if detected, along with prevention and public education.

Montana Priority 1B Noxious Weeds

Weed species with limited presence in Montana whose official management status is eradication or containment paired with education.

Montana Priority 2A Noxious Weeds

Weeds that are common in isolated areas of Montana, managed through containment or eradication where populations are less abundant.

Montana Priority 2B Noxious Weeds

Weed species that are abundant across Montana, prioritized for eradication or containment by local weed districts where less abundant.

Montana Priority 3 Regulated Plants

Plant species that are officially regulated in Montana because they have the potential to cause significant negative ecological or agricultural impacts.

Growth Regulating Herbicides

Herbicides that mimic the natural plant hormone auxin to disrupt normal growth and development, acting selectively against broadleaf plants through foliar or root absorption.

Amino Acid Synthesis Inhibitors

Herbicides that block key plant enzymes needed to synthesize essential amino acids and proteins, providing slow-acting but effective plant mortality.

Photosynthesis Inhibitors

Herbicides that block the photosynthetic pathway, generating destructive free radicals that break down plant cell membranes, commonly used for perennial weeds and often persisting long in the soil.

Classical Biocontrol

The practice of introducing specialized natural enemies (such as insects, nematodes, or fungal pathogens) from an invasive plant's native home range to depress its population in an invaded ecosystem.

USDA-APHIS

The Animal and Plant Health Inspection Service; the United States regulatory body overseeing the quarantine, testing, and approval process of imported biological control agents, which typically takes around $11\,\text{years}$.