General Technical Report RMRS-GTR-22
The Northern Goshawk in Utah: Habitat Assessment and Management
Recommendations
General Technical Report RMRS-GTR-22
The Northern Goshawk in Utah: Habitat Assessment and Management Recommendations
Assessment Questions
This assessment has attempted throughout these pages to answer the questions initially posed in the "Introduction" section. These questions are repeated below with brief answers that synthesize the substantial, comprehensive information contained herein.
1. Is there adequate nesting habitat available?
Presently there appears to be adequate nesting habitat in the State to maintain a breeding population of goshawks. Based on the presence of habitat features and cover types that are important to goshawks, nearly all the montane forests of Utah are of either high or medium value for nesting (map 3). The only areas consistently rated as low value for nesting were pinyon/juniper woodlands.
2. Is there adequate foraging habitat available?
Based on habitat features important to selected prey used by goshawks, it appears that foraging habitat is presently available throughout the State. Nearly all the forested lands in the State contained medium-rated or better habitat for two or more prey groups. Even much of the pinyon/juniper woodland type has good prey habitat.
3. Are northern goshawks able to move freely among all available habitat patches?
Goshawks appear to be able to move freely among habitat patches throughout Utah. Using a conservative estimate of 20 to 60 miles as the distances over which goshawks explore habitats annually, all patches of high value habitat are likely to be detected from one or more adjacent high value patches (map 9). In most cases, the patches are contiguous or separated by distances of less than 20 miles. The longest distance between patches occurs in southeastern Utah, where high value habitat in the La Sal and Abajo Mountains is more than 60 miles from the nearest high value habitat elsewhere in Utah. These areas are likely connected to habitat in Colorado.
4. Is the population viable at the State level?
This assessment cannot answer the question of population viability directly because there are inadequate demographic data available. Most of the currently forested lands were rated as medium or high value for both nesting and foraging habitat. Where surveys have been conducted, goshawks are present and are nesting successfully. Furthermore, all available habitat patches are connected, and no known population is isolated. In general, existing habitat appears to be capable of supporting a viable population of goshawks at the State spatial scale. However, even though high quality habitat does not appear to be lacking at the State spatial scale, on the local landscape, habitat deficiencies may be present.
5. Where is the high value habitat?
High value habitat is distributed throughout the State, with 60 percent controlled by the USDA Forest Service (map 7, table 19).
6. How are current management policies affecting northern goshawks?
Current management policies are affecting northern goshawks in a variety of ways. On National Forest Service administered lands, 20 percent of the high value habitat is being managed with a timber emphasis, 35 percent with mixed uses, and 27 percent with a range emphasis. Each of these management categories allows for activities that either can degrade or improve goshawk habitat. The information in this assessment does not reveal any substantial deficiencies in habitat quality in any management category (tables 22, 23, 24, 25). There are two possible explanations for these results: (1) management activities are having no negative effect on goshawk habitat; (2) management activities are having some negative effects on goshawk habitat, but the effects are not detectable at either scale used in this assessment. No data are available to determine which is the true explanation. Current management policies have the potential to degrade habitat if any one activity is over-applied or misapplied. For example, timber harvesting can convert mature stands to younger structures, which can negatively impact goshawks. Range management can affect goshawks when it removes cover and food for prey and when it interferes with the regeneration of quaking aspen stands. Both wild ungulates and domestic livestock can browse suckers, and if repeated frequently, quaking aspen clones can be replaced by other vegetation. In contrast, current management policies provide latitude for improving goshawk habitat if applied within reasonable ecological constraints. For example, partial cutting systems used to maintain or improve stand characteristics for goshawks and their prey would have an overall positive effect on goshawk habitat. In addition, timber harvesting has the potential to convert cover types to earlier seral vegetative communities, which is generally good for goshawks. Thus current management policies provide for a wide range of implementation options, with a correspondingly wide range of possible effects on goshawk habitat. The critical decisions are those being made on individual project level analyses, because this is where managers can use the best available information to ensure that projects are providing for goshawk habitat needs.
7. What are the important habitat trends and their implications for goshawks?
The most obvious trend in Utah forests and woodlands is the lack of early and mid-seral species in all of the potential vegetation types. Existing stands on the Douglas-fir and white fir potential vegetation types are highly unstable and stands on the ponderosa pine potential vegetation type are at high risk to stand-replacing fire events. If forest management stresses properly functioning condition, importance of large trees, maintaining native processes, using adaptive management, and recognizing the role of fires, the habitat outlook could be favorable for the goshawk and its prey. Development of procedures and techniques to protect large trees during restoration treatments, and to grow them at accelerated rates, will also help improve the outlook for structural aspects of goshawk habitat, especially in the ponderosa pine potential vegetation type.
Urbanization and more intensive uses of the forests by humans could degrade goshawk habitat, especially on private lands. Private lands in Utah will continue to be developed, making the lands administered by Federal entities increasingly important for goshawks. This trend could also affect the connectivity of the habitat across the State.
Title: Assessment
Questions: RMRS-GTR-22 - The Northern
Goshawk in Utah: Habitat Assessment and Management Recommendations
Electronic Publish Date: May 26, 1999
Expires: Indefinite
Last Update: January
15, 2002