Study

Sage grouse versus sagebrush control in Idaho

Summary

Whether to use rotational burning or herbicides to manage native sagebrush-grassland may have implications for sage grouse Centrocercus urophasianus, a declining North American ground-nesting bird (as well as other fauna and flora). A study was conducted on native upland sagebrush-grassland at the US Sheep Experiment Station on the Upper Snake River Plains (southeastern Idaho) to evaluate if sagebrush Artemesia control by herbicide spraying and/or burning, affected grouse nest and brood densities.

Sage grouse nest and brood searches were conducted within 34 plots (10 burned; 3 sprayed; 2.5 burned and sprayed, and 18.5 untreated) of 40 acres (16.2 ha) on foot assisted by trained dogs, and by vehicle. Six plots were searched in summer 1964; all 34 in 1965; 16 plots with nests in previous years were searched, plus an additional 460 acres (186.2 ha) of ‘suspected nesting habitat’, in 1966.

Within the study area, 1,311 ha had been sprayed; one area treated in 1964 and others up to five years previously. Burn sites had been burnt by wildfires (1936 to 1957) or in one case subject to a prescribed burn in 1953.
 
Within each plot, 10 randomly positioned circular plots (37.2 m²), plus one at each nest and brood location, were established to describe vegetation. The following were recorded: number of shrubs (by species); line intercept of shrub crowns along two transects crossing at the plot centre; height of 10 shrubs per species; an estimate of species basal area and litter cover in 10 (30 x 60cm) plots along each transect.

Thirty-two current year nests plus 55 old nests were located.
 
In 220 acres searched where sagebrush had been herbicide-sprayed, only one new nest was found (in an area sprayed 5 years earlier) in 1964. The area sprayed in 1964 contained one nest that year prior to spraying (plus one from1963). Three old pre-spray nests were found on other areas. No further nesting on the area sprayed in 1964, and the single nest on other sprayed areas suggest that herbicide treatment was detrimental to nesting.
 
Results from the burned areas were deemed inconclusive: on 200 acres burned in 1957 but not sprayed (greater average shrub cover than untreated areas) three new nests (1 nest/67 acres) were found; (no further data on location/numbers of nests found presented in the original paper).
 
Sage grouse selected habitats for nesting most like that present in untreated or burned areas (i.e. with higher shrub and forb cover than sprayed areas).
 
Broods (n=98) used the untreated and burned areas more than the sprayed areas and tended to select habitat with greater than average total shrub cover.
 
 
Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at:

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust