The Bureau of Land Management (BLM) has launched a massive juniper removal project in Idaho and plans to expand it throughout the Great Basin. Juniper is a common native species that grow in arid landscapes along with sagebrush and grasses.
The rationale given for the juniper removal is to improve sage grouse habitat. However, that is a red herring. The real reason is to create more forage for private livestock. Juniper removal gives the public the impression that the agencies are doing “something” to enhance sage grouse survival.
The BLM and the livestock industry suggest that juniper deforestation will benefit sage grouse because the juniper is occasionally used as perches by avian predators.
There are no studies that I’m aware of that demonstrate that use of juniper as perches by sage grouse raptor predators is common.
Furthermore, much of the habitat where juniper removal is occurring is steeper ground not typically utilized by sage grouse.
There is one paper that suggests that juniper removal potentially increases sage grouse nest and adult survival by up to 25% which they attribute to removal of perches for birds of prey. However, like other papers, the authors do not demonstrate that birds of prey are the main culprit for sage grouse mortality. They assume that juniper removal reduces avian predator losses, but the evidence is not conclusive.
Ravens, another bird that occasionally preys on nests and eggs, will use scattered juniper for perches. However, this does not appear to be common.
Plus there is evidence that the presence of livestock (dead livestock and afterbirth) leads to higher raven numbers.
However, many studies show that birds of prey like golden eagles use fence posts for perching. In areas where junipers have been removed, sage grouse tend to avoid the areas that have fences.
Besides, up to 30% of the mortality of sage grouse in some areas is due to collision with fences. Thus, if the BLM were genuinely concerned about the future of sage grouse, it would be eliminating or decreasing fences, not juniper.
Livestock degrades sagebrush habitat by eating and trampling and thereby, decreasing the hiding cover of grass exposing the bird to higher predation losses.
The bulk of BLM lands are in poor to fair condition, meaning grass cover is less than desirable. It’s possible that removing or reducing livestock grazing might lead to much higher sage grouse survival than juniper removal. However, this alternative is never considered by the BLM due to its strong alliance to the livestock industry.
Livestock production also impacts sage grouse by the damage done to wetlands and riparian areas from trampling, the resultant soil compaction, and loss of vegetative cover due to livestock grazing. Sage grouse chicks are dependent on these wet areas where they feed on insects and specific flowers.
Livestock water troughs are used by mosquitoes that carry West Nile Virus, which can cause significant mortality in sage grouse.
Sage grouse avoid flying over vast expanses of non-sagebrush habitat created by hay fields. Considering many valley bottoms around the West have been converted to hay production, the resulting habitat fragmentation is significant.
Perhaps one of the main ways that livestock production harms sage grouse is by the spread of cheatgrass. Cheatgrass is an alien annual grass that is highly flammable. Cheatgrass spread is facilitated by livestock due to the selective grazing of native grasses. Removal of native grasses by livestock gives cheatgrass a competitive advantage in the competition for resources like water.
Furthermore, cattle hooves trample soil biocrusts, which generally grow in the spaces between native bunchgrasses. Biocrusts inhibit the establishment of cheatgrass.
Collectively all these livestock production factors create a “headwind” for sage grouse survival in many parts of the West. (Energy production, conversion of sagebrush habitat to wheat and hayfields, and so forth are also factors in sage grouse decline).
Another problem associated with the BLM justification for juniper removal is the use of old ideas about juniper and fire. According to the standard party line given by range conservationists and range professors (both of whom indirectly work on behalf of the livestock industry), juniper is “invading” due to “fire suppression.”
This myth was created by a range professor from Oregon State University Range Department who asserted that since range fires were frequent and low severity, burning sagebrush ecosystems every 10-25 years. Such recurrent blazes would logically preclude the establishment of juniper except on rocky sites and other areas where a fire was excluded.
However, more recent research has concluded that most sagebrush species typically burn on a 50-400 year fire rotation. So this creates a problem for the BLM argument that “frequent” fires limited juniper since it turns out that fires were not that regular.
In a more recent review of juniper fire ecology, the researchers concluded that “spreading, low-severity surface fires were likely not common.” Instead of low severity fires, the researchers found that “nearly all observed fires since EuroAmerican settlement in these woodlands were high-severity fires.”
Several more recent studies on juniper have verified this long rotation. For instance, a survey conducted in Dinosaur National Monument found that juniper fire rotations were 550 years. Similar long fire rotations of 400 years in one case, 480 years in the other have been reported.
Therefore, much of what is viewed as juniper “expansion” may be recolonization after high severity fires. Climate change may also be contributing to juniper expansion. Juniper establishment only occurs when there are favorable conditions for seed production and seedling survival. Seedling survival is better in disturbed rangelands where livestock have decreased the competition from other vegetation.
All of which the BLM appears to ignore because it doesn’t fit the paradigm that justifies juniper removal.
The BLM does not address that juniper removal, and the disturbance that comes with it promotes the establishment and spread of cheatgrass. The highly flammable cheatgrass by shortening the regular fire rotation is a far greater threat to sagebrush ecosystems and sage grouse survival than the presence of juniper.
It’s essential to keep in mind that range conservationists and/or range professors/researchers whose jobs depend on the continuation of livestock grazing are the primary advocates of juniper removal. Just follow the money.
To the degree, that juniper removal might, in some cases, benefit sage grouse is a distraction or smoke screen. The more significant factors contributing to sage grouse declines, which include the cumulative impacts of livestock production continued to be ignored.