• FIRE ECOLOGY OR ADAPTATIONS
• POSTFIRE REGENERATION STRATEGY

FIRE ECOLOGY OR ADAPTATIONS:

Because blackbrush is a nonsprouter, very susceptible to fire, and slow to reinvade sites, it is removed by fire [17,128], and succeeding communities are variable [17]. Fire in blackbrush stands in southwestern Utah resulted in a variety of species dominating the postfire vegetation [3,17]. These postfire dominants include turpentine bush, desert bitterbrush, desert almond, big sagebrush, and some nearly monospecific stands of broom snakeweed [17]. Grasses are more abundant in burned blackbrush communities [116], and burning may improve forage productivity [128]. One 10-year-old burn in blackbrush was devoid of blackbrush and dominated by brittlebrush and desert mallow, with a denser cover of red brome and cheatgrass compared to exotic brome cover in the adjacent unburned blackbrush community [97]. In another study of burned blackbrush sites in southwestern Utah, most shrubs were removed by fire. In the 1st postfire year, forbs greatly increased and grasses moderately increased. Forbs steadily decreased over time, approaching prefire levels, while grasses steadily increased, peaked at postfire year 6, and then declined to prefire levels. Shrub dominance on these sites returned within 20 years, but shrub composition after burning only slightly resembled composition before fire. Blackbrush cover was greatly reduced on all sites. Cryptogamic soil crusts associated with blackbrush communities were also strongly affected by fire. Before burning cryptogamic crusts contributed 9% of plant cover but were reduced to less than 1% of total plant cover after fire. There was very little evidence of crust formation after 19 postburn years [24]. Fire has promoted succession to grassland by destroying the cryptogamic crust, which stabilizes the soil [72].

Blackbrush fire regime: The blackbrush association is composed of dense to scattered low-stature shrubs and dense to open grasses, and it maintains the highest cover of any desert shrub community. Blackbrush experiences a stand-replacement fire regime, though historical documentation of blackbrush fire cycles is limited. Frequent large fires have eliminated blackbrush from some areas. Fuel production in blackbrush ranges from 250 to 500 lbs/acre, and blackbrush is negatively associated with fine fuels of litter and grasses. Blackbrush occurs in areas with approximately 7 inches (180 mm) of annual precipitation, and cyclic desert precipitation above 10 to 14 inches (250-360 mm) may increase biomass and fuel continuity enough to increase fire behavior potential [72]. 

The following table provides some fire regime intervals for ecosystems where blackbrush occurs:

POSTFIRE REGENERATION STRATEGY [101]:

Related categories for SPECIES: Coleogyne ramosissima | Blackbrush