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5322

Ecological site R024XY001NV

DUNES 6-10 P.Z.

Home / Esd catalog / MLRA 024X / Ecological site R024XY001NV
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T1A - Trigger: Introduction of non-native annual species. Slow variables: Changes in the kinds of animals and their grazing patterns, drought and/or changes in fire history that altered recruitment rates of native species. Threshold: Reduction in deep-rooted herbaceous understory reduces productivity, changes nutrient cycling and soil stability. Annual non-native species cannot be easily removed from the system and have the potential to significantly alter disturbance regimes from their historic range of variation.
T2A - Trigger: Inadequate rest and recovery from growing season defoliation and/or prolonged drought. Slow variables: Long term decrease in grass density and reduced native species (shrub and grass) recruitment rates. Increased reproduction of non-native species. Threshold: Loss of deep-rooted perennial bunchgrasses changes nutrient cycling, nutrient redistribution, and reduces soil organic matter.
T2B - Trigger: Multiple stand replacing fires eliminate sagebrush and severely damage spiny hopsage. Typically occurs in the hot season. Slow variables: Increased reproduction and cover of non-native invasive annuals. Threshold: Loss of deep-rooted perennial bunchgrasses reduces infiltration and increases runoff; this leads to reduced soil organic matter and soil moisture. Modified fire regime (changes in intensity, size and spatial variability of fires).
T3A - Trigger: Multiple fires within a 10 to 20 year timeframe Slow Variables: Increased reproduction, cover and density of non-native annuals Threshold: Modified fire regime (changes in frequency, intensity, size and spatial variability of fire). Changes in plant community composition and spatial variability of vegetation (loss of perennial bunchgrasses and sagebrush).
1.1A - This community pathway is a result of fire, insect or disease attack.
1.1B - This community pathway is a result of prolonged drought, inadequate rest and recovery from defoliation and the absence or fire or other natural disturbances.
1.2A - This community pathway is a result of absence of disturbance and natural regeneration over time. Ten years or greater is required for big sagebrush to reach pre-fire conditions (Tirmenstein 1999).
1.3A - This pathway is a result of fast moving, low intensity fire, Aroga moth infestation of big sagebrush, adequate rest and recovery from defoliation or a release from drought which removes shrub overstory and releases bunchgrass understory.
1.3B - This community phase pathway is a result of stand replacing fire or other natural disturbance that reduce shrub cover and invigorates the perennial bunchgrass community.
2.1A - This community phase pathway is a result of fire, insect or disease attack.
2.1B - This community pathway is a result of prolonged drought, inadequate rest and recovery from defoliation and absence of fire or other natural disturbance.
2.2A - The community pathway is a result of absence of disturbance and natural regeneration over time. Ten years or greater is required for big sagebrush to reach pre-fire conditions (Tirmenstein 1999).
2.3A - This community pathway is a result of fast moving, low intensity fire, Aroga moth infestation, adequate rest and recovery from defoliation or release from drought which removes shrub overstory and releases bunchgrass understory.
2.3B - This community phase pathway is a result of stand replacing fire (most likely during the dormant season) insect or disease attack. Non-native annuals may increase.
3.1A - This community phase pathway is a result of fire, insect or disease attack.
3.2A - This community phase pathway is a result of absence of disturbance (fire return interval >20 years) and natural regeneration over time (if a seed source is present for sagebrush).
4.1a - This pathway is a result of time without disturbance to facilitate sprouting of shrubs.
4.2a - This community phase pathway is a result of fire.