Habitat-related Fire Effects
Fire may be beneficial or detrimental to sage-grouse, depending on the particular setting and location relative to seasonal changes . Sage-grouse use sagebrush of different age classes and stand structure for different life history events at different seasons. Fire effects on these different sagebrush habitats vary and are treated separately. Additionally, some sage-grouse populations are migratory and others sedentary. Whether a population is migratory or not is dependent on precipitation, vegetation, and elevation [28,29]. Where precipitation is less than 10.4 inches/year (260 mm/yr)  or where sage-grouse move more than 10 miles (16 km)  to a seasonal range, populations are considered migratory. Plant communities that support these populations reflect differences in precipitation and elevation and may exhibit different fire effects. Where there is sufficient literature, differences in migratory and sedentary populations relative to HABITAT RELATED FIRE EFFECTS are discussed.
Breeding: Leks, where breeding occurs, are usually small open areas from 0.1 to 10.0 acres (0.4-4.0 ha) in size, but may be as large as 100 acres (40.5 ha) . Effects of fire on the lek itself are not as much a concern as they are on the area around the lek . This area is used by sage-grouse for loafing, feeding, and escape cover [4,73]. A study by Wallestad and Schladweiler  in Montana recorded sagebrush cover and height at 110 daytime sites of cock greater sage-grouse and found 80% of the locations occurred in sagebrush with a canopy cover of 20-50%. Sagebrush canopy cover for the 110 sites averaged 36%. Also in Montana, Eng and Schladweiler  found that a cock-use area during the breeding season had canopy coverage of sagebrush averaging 30%. In Idaho, Autenrieth  found 80% of cock greater sage-grouse locations occurred in sagebrush stands of 20-50% canopy coverage.
An Idaho study by Martin , after wildfires in 1981, found greater sage-grouse continued to use leks located within extensive burns. Attendance of males at burned leks did not decrease (after adjusting for population declines) despite extensive reduction of surrounding shrub cover. During this study, males and females attended leks in spite of the loss of vegetative cover immediately surrounding leks. Greater sage-grouse seemed to adapt to loss of sagebrush in travel corridors and in principal breeding season habitat of cocks. Cocks and hens appeared to feed, loaf, and roost primarily in unburned habitat and fly into burned leks. Martin found greater sage-grouse attended burned and unburned leks within perimeters of large burns and suggested there are 2 factors that account for why greater sage-grouse attended burned leks in his study area: 1) The summer wildfire burn occurred in a mosaic pattern and left many unburned islands, so abundant nesting habitat was available near all leks within the burn. 2) The long-term population within the burn area was well below average population when the burn occurred, allowing the smaller unburned portions of the study area to supply necessary habitat requirements. Gates  observed greater sage-grouse displaying and mating on a burned area in Idaho during the 1st 2 breeding seasons following a burn. These observations also took place during a population decline.
Fischer  studied lek attendance patterns after a late-summer prescribed burn on the upper Snake River Plain of southwestern Idaho. He could detect no differences attributable to fire after 2 years. However, an additional year of data on lek attendance and further analysis of lek data from Fischer's study provide evidence that fire had a negative influence on the breeding population in the treatment area . The notion that fire had negative effects on the greater sage-grouse breeding population in the treatment area is supported by 4 findings: 1) The treatment area had a higher loss of leks (-58%) than did the control area (-35%). 2) Changes in attendance in major leks by males were similar in treatment and control areas during the preburn period but the treatment area had a greater decline in attendance (-90%) than the control area (-63%) during the postburn period. 3) Average lek attendance at the 2 largest leks in both areas was greater in the treatment (67 males) than the control (59 males) area during the preburn period. However, the situation reversed during the postburn period, and average attendance at the 2 treatment leks (22 males) was less than the average attendance at the control leks (36 males). 4) The mean number of male greater sage-grouse per lek was similar in treatment and control areas during the preburn period but was much lower in the treatment area (6 males) than in the control area (17 males) during the postburn period.
In a study in Idaho, Connelly and others  found some greater sage-grouse leks persist even after sagebrush areas have been burned. Data from the study suggest that greater sage-grouse continue to use leks in altered areas because some hens nest successfully under nonsagebrush plants. The authors caution that persistence of leks in burned areas should not be interpreted as evidence that fire has little effect on greater sage-grouse populations. Greater sage-grouse use of nonsagebrush shrubs for nest sites may allow populations to persist at low levels in a burned area until the area recovers. However, this behavior may only slow, but not prevent, the birds' ultimate disappearance from the burned area.
Leks used by migratory populations of sage-grouse appear to be more susceptible to deleterious HABITAT RELATED FIRE EFFECTS because they are usually dominated by Wyoming big sagebrush  which re-establishes slowly following fire . Degradation of breeding range because of fire, drought, grazing, or herbicides will likely reduce sage-grouse populations because of low nesting effort, low nest success, or poor chick survival. Regardless of the method used to eliminate or reduce sagebrush cover in xeric sage-grouse breeding habitat, these actions have the potential for reducing breeding populations of grouse. It is recommended that prescribed burning be avoided in relatively xeric habitats used by breeding migratory sage-grouse. If a Wyoming big sagebrush habitat type supports a breeding population of sage-grouse, it is recommended a high priority be given to suppressing wildfires in these habitats during drought .
Nesting: After mating, hens disperse to nest . Most nest near leks, and areas within a 1.9 mile (3 km) radius of leks is considered the most important for nesting . Some hens may fly as far as 32 to 48 miles (20-30 km) to nest . Nesting habitat is often a belt between summer and winter range . Often there is a complex of habitat types centered around a lek. In nonmigratory populations of sage-grouse, this complex may provide for year-round needs of the birds. In migratory populations, this suite of habitat types often includes breeding, nesting, early brood-rearing, and winter habitats, and sage-grouse migrate to fill their summer needs .
Gill  found that Gunnison sage-grouse nested under all types of shrub cover on his study area in Colorado, but preferred sagebrush, with 92.3% of 117 nests located under sagebrush. Shrub heights preferred for nesting varied from 11.8 to 23.6 inches (30-60 cm), with 7.9 to 31.5 inches (20-80 cm) adequate and shrub canopy coverage > 17% . In Idaho, Klebenow  found no greater sage-grouse nested in the most arid, open areas (< 10% total shrub cover, mean shrub canopy coverage at 87 nest sites = 18.4%). In more dense cover, greater sage-grouse did not nest where total shrub cover was > 25% .
Complete removal of sagebrush in burned areas could reduce nesting, hiding, and wintering cover for sage-grouse . Sage-grouse show fidelity to leks and/or nesting areas [13,48]. A study on the Big Desert, in Idaho, by Fischer and others , found that because greater sage-grouse hens appear to seek suitable habitat within a relatively small area, nest area fidelity may reduce nesting if large areas of nesting habitat are destroyed. Hens may nest in unsuitable areas and experience lower nest success .
Klebenow  states the cover shrubs provide is necessary for nesting greater sage-grouse, and complete removal of shrubs can only result in elimination of greater sage-grouse from the area. Fire eliminates potential winter and nesting habitat according to Robertson  and Fischer . Connelly and Braun  feel fire may negatively impact sage-grouse populations by eliminating or fragmenting relatively large blocks of wintering or nesting habitat. During the 1st few years after burning, nesting habitat is essentially destroyed .
Fischer  studied the effects of fire on migratory greater sage-grouse breeding, nesting, and brood-rearing habitat in southeastern Idaho. Nests inside the burned area were only found in unburned patches, suggesting that removal of sagebrush by fire reduces nesting cover for grouse. Although no immediate differences in use of burned and unburned habitat were demonstrated in this study for 3 postfire years, long-term response of nesting greater sage-grouse to fire may be dependent on both the scale of sagebrush removal and intensity of fidelity to nesting areas. Greater sage-grouse that show nesting-area fidelity may subsequently return to the same area and attempt a nest even after the habitat has been manipulated. Attenuation of nest-area fidelity as site-tenacious individuals die may decrease production in the burned area. Fire may also reduce the number of suitable nesting sites by removing shrub cover for nests.
Brood rearing: The single unifying theme threatening sage-grouse across their geographical range is the universality of brood habitat loss . Drought and increased fire frequency may be the primary agents causing a decline in brood-rearing habitat for sage-grouse. Moreover, an unfavorable situation due to drought and an increase in wildfire may have been made worse in many areas by vigorous prescribed burning . Brood habitat typically has 15-25% shrub canopy closure but at least 10-20% cover of live forbs and grasses . In southern Idaho, the percent canopy cover of big sagebrush at brood sites was 8.5%, significantly less than the average for the entire area, 14.3% .
Broods are tied to food in addition to cover . After hatching, before chicks can fly and when mortality is highest [4,92], broods need food in close proximity to escape cover . Diet of sage-grouse chicks is chiefly insects early in life, shifting to succulent forbs and shrub foliage as chicks grow older [75,92,95]. Abundant food forbs in close proximity to unburned sagebrush cover could benefit sage-grouse broods by providing additional food with adequate cover, and fire-enhanced flowering may improve forage availability for sage-grouse during the brood rearing period . Sime  states openings in sagebrush canopy may increase forbs and improve brood habitat, and Klebenow  suggests reduced shrub cover on burned sites may increase accessibility of forbs and insects to chicks. In a 2-year study of greater sage-grouse responses to wildfire in Idaho, Martin  found that burning improved habitat for sage-grouse broods. During both postburn years, forb crown cover was significantly higher in burned habitats than in unburned habitats. However, Nelle and others  found that during the 1st few years after burning on a site in southeastern Idaho, greater sage-grouse brood-rearing habitat was not improved.
After a prescribed burn on the Snake River plain of southeastern Idaho, Connelly and others  found no difference in the use of burned and unburned areas by a migratory population of greater sage-grouse. These results suggest fire does not improve brood-rearing habitat in relatively low precipitation areas dominated by Wyoming big sagebrush. The authors were unable to show an increase in forbs following the fire, so fire may have caused an overall decline in brood-rearing habitat, perhaps contributing to the decline in greater sage-grouse population following the fire. Decreased food abundance following fire in the treatment area may have indirectly affected survival by increasing chick movement. Fire in Wyoming big sagebrush has not been reported to increase the length of the growing season for forbs important in the diet of sage-grouse .
Fischer's  research in southeastern Idaho provided evidence for excluding fires that eliminate large blocks of vegetation in brood habitat for migratory greater sage-grouse within xeric regions, because of its impact on insects. Fire appeared to negatively impact insect abundance in 1 of the 3 orders that are most important in sage-grouse diets. The fire created a mosaic of sagebrush areas interspersed with open areas having abundant grasses and forbs, but there was no positive response of greater sage-grouse to the burned area. Broods require food, mainly forbs, in addition to cover. Both may be present in a given acre of land, but the birds also use and appear to seek areas where there is an interspersion of habitat types. They only feed in areas where cover is nearby .
A study by Fischer and others  in southeastern Idaho indicated that short-term effects of a prescribed fire in a xeric environment did not enhance brood-rearing habitat and may have been detrimental to grasshoppers which are important in sage-grouse diets. Gates and Eng  examined use of burned areas by migratory greater sage-grouse after prescribed burns in 1981 and 1982 at the Idaho National Engineering Laboratory. They suggested the patchy burn which occurred could enhance early brood-rearing habitat. If availability of forbs and insects were enhanced on burned areas, then an abundant food supply would be available to broods in close proximity to escape cover.
Summer: Sage-grouse have been reported to be attracted to burn areas during summer [74,84]. Summer habitat is characterized by shrub canopy cover of at least 15% and at least 10% live forb cover . Sagebrush and forbs are essential components of summer sage-grouse habitat . If fire increases availability of photosynthesizing, succulent foods in uplands during the late summer, available sage-grouse habitat may be increased .
Connelly and others  studied migratory greater sage-grouse response to a controlled burn on the upper Snake River Plain of southeastern Idaho. They found fire apparently had no influence on the timing of migration of female greater sage-grouse. However, they found the summer population associated with the burn area declined 75% while that in the control area declined 52%. A similar but more pronounced decline occurred at the largest lek in the burned area. Estimated summer population associated with this lek declined 98% during the 9-year study while the population associated with a similar lek in the unburned area only declined 45%.
Migratory greater sage-grouse in a xeric habitat were studied by Fischer  in Idaho. He found that cover of forbs important in greater sage-grouse summer diets was similar in burned and unburned habitats. Although the fire created a mosaic of sagebrush areas interspersed with open areas having abundant grasses and forbs, there was no movement of greater sage-grouse to the burned area.
Winter: Many researchers [10,45,92] describe winter habitat as probably the most limiting seasonal habitat and thus perhaps the most critical . The majority of winter observations are in sagebrush with more than 20% canopy coverage . Connelly and others  describe sage-grouse wintering habitat as open to moderately dense sagebrush with 10-20% canopy cover. For sedentary populations of sage-grouse, the wintering area is often located within 2 miles (3.2 km) of the strutting ground and nesting area .
Fire may negatively impact sage-grouse populations by eliminating or fragmenting relatively large blocks of wintering habitat  and at times, severe fires destroy important wintering areas for sage-grouse . Sage-grouse show affinity for particular winter ranges [13,45], and known sage-grouse wintering areas should receive priority attention in the control of wildfires . Lack of protection of critical winter habitat has resulted in sage-grouse population declines , and Sime  states it is imperative that winter sage-grouse habitat be protected. Braun and others  caution that complete removal of sagebrush in burned areas could reduce nesting, hiding, and wintering cover for sage-grouse. Gates and Eng  suggest elimination of sagebrush by burning will destroy wintering habitat for grouse.
In areas where winter habitat is limiting, loss of contiguous sagebrush rangeland could negatively impact sage-grouse by removing food and cover. Robertson  conducted a study of a migratory greater sage-grouse population in a xeric habitat in Idaho. He found burning decreased the structural components of greater sage-grouse winter habitat, and use of these areas decreased dramatically. This does not imply that that burning is detrimental to greater sage-grouse with large expanses of winter habitat. If burning takes place on critical winter range, and heavy snow fall covers much of the remaining habitat during the following winter, food and cover may be severely limited. Klebenow  suggests there is little place for fire on wintering sites of migratory greater sage-grouse in xeric habitat since there is nearly a complete reliance on shrubs for food and cover.
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