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Assessment of Wildlife Use of SITLA Property in Castle Valley, Utah, with Recommendations and Suggestions to Reduce Impacts to Wildlife while Accommodating Potential Development
Craig Johnson, Landscape Architect and Wildlife Biologist, Logan, Utah
IntroductionThe Castle Valley SITLA property supports four integrated plant communities. These plant communities in turn support and are modified by a diverse community of wildlife (see appendix). Of particular concern to the Utah Division of Wildlife Resource (UDWR) and federal agency biologists is the populations of mule deer that utilize the SITLA site during the winter months.
In southern Utah, year to year high variability in environmental conditions is common. This variability is a major source of variability in the number of overwintering fawns and, thus, often dramatic fluctuations in the deer population.
Deer and elk from the north La Sal mountain herd migrate down off the La Sal Mountains into Castle Valley once snow precludes their access to browse plants. An estimated 1,000 deer wintered in Castle Valley during 1999-2000 (BLM Biologist). This an estimated 16.6% of the deer herd that summers in the La Sal Mountains (UDWR Biologist). Big game animals are frequently stressed during winter and early spring and are highly dependent on winter range resources. Black bears and cougars also utilize the area.
The eastern two thirds of the SITLA Castle Valley property is one of the largest patches of relatively undisturbed high quality winter browse, particularly large stands of blackbrush and sagebrush in the immediate area. Consequently, the UDWR has classified virtually the entire site as critical winter range for deer. Elk also occasionally winter on the site but typically utilize higher elevation habitat. On-site observations including heavily browsed/grazed blackbrush and sagebrush, a high density of deer scat, and numerous game trails suggest intensive use of the site by big game during the winter months. Although the most concentrated use is on the south flank of Round Mountain (a traditional pattern), they roam the entire SITLA property (BLM Biologist).
There are several species of birds that breed in the SITLA property. In addition, many more species likely use Castle Valley as a migration route. These species migrate up the Colorado River in spring; some diverge and move through Castle Valley to breed in various foothill and forest habitats in the La Sal Mountains. Peregrine falcons are also known to utilize the site (BLM Biologist). There is an active nest site at mile post 11.5 on River Road just north and west of Castle Valley. Golden eagles have also been observed in the valley (UDWR Biologist). In addition, there is a diverse community of small mammals and several species of reptiles that inhabit the site.
Landscape Scale Context
The Castle Valley SITLA property is a "keyhole" inholding surrounded by Bureau of
Land Management property on the north and south, U.S. Forest Service land, and a small
area of private property on the east. Existing Castle Valley development abuts the property
to the west. Sections of the abutting BLM properties are identified as Wilderness Study
Areas. Although not specifically managed for big game, the BLM Resource Management
Plan identifies these areas as important habitat for mule deer.
Similarly, the U. S. Forest Service (FS) Forest plan identifies its abutting lands as important winter range particularly for elk. It is also a migration corridor for deer and elk (Forest Service Biologist). Discussions with the BLM and FS personnel reinforce earlier observations that the SITLA property is critical winter range for deer herds that summer on abutting federal lands. The UDWR is also concerned that additional development in Castle Valley will lead to additional wildlife depredation problems, problems which are already substantial. In nearby Fisher Valley, 25-2 doe permits have been issued to reduce depredation problem, eliminating reproductive units from a population that is already in serious decline. In addition, UDWR concerns were expressed for other non-game wildlife species of concern (state listed) which include the Western Red Bat, Dwarf Shrew, and Peregrine Falcon that inhabit the SITLA property. Further field research would be required to verify species presence or absence.
Some wildlife related dispersed recreation occurs on the site. Deer hunting with muzzle-loading rifles is permitted on the SITLA property. Dove hunting and wildlife observation are other recreation activities in the area. Deer hunting is a significant social event in the region and generates considerable economic revenue to local economies (UDWR Biologist).
General Wildlife Habitat Conservation Planning Concepts
It is important to maintain habitat in large contiguous blocks. It is also important to
conserve corridors for wildlife migration, dispersal, and daily movement both within and
between patches. In general, wide corridors are better than narrow corridors for large
bodied animals like deer, elk, bear, and cougar and in areas where human development and
activity are present. Special landscape features such as cliffs, boulder fields, and dead
snags are also important habitats for some species.
General Recommendations
A traditional rural subdivision plan, grid roads, uniform lot sizes (5 acres), equally
spaced housing units, and no conservation covenants would have significant adverse
impacts to wildlife (particularly big game) on the SITLA property. It would fragment
critical deer winter range, bisect important migration corridors, eliminate habitat, increase
soil erosion, and likely accelerate the dispersal of invasive exotic vegetation that is of little
value to wildlife. A traditional subdivision on the SITLA property could lead to the
exterpation of the north La Sal Mountains deer herd (BLM Biologist). Considerable
wildlife habitat has already been compromised within the existing development to the west
of SITLA lands.
By using principles from conservation biology, landscape ecology, wildlife management as summarized above (see Conservation Corridor Planning at the Landscape Level: Managing for Wildlife Habitat), and contemporary concepts from landscape architecture, limited development is possible with limited adverse impacts to wildlife.
A limited, very carefully planned development with strict conservation covenants (deed restrictions) that are enforced would afford landowners access to property with world class views and settings for homes. It would also reduce impacts to wildlife and their habitat well below those associated with traditional subdivision practice. To accomplish these ends the following recommendations and suggestions are made.
Specific Recommendations (See map)
- Conserve the habitat value on as much of the of the SITLA property as possible. This suggests limiting or eliminating development on the upper two thirds of the site to conserve large contiguous patches linking BLM land to the north and south and FS land to the east _ in particular, the south and east flanks of Round Mountain. These are the areas traditionally used most intensively by mule deer as winter range.
- Preserve major east/west wildlife corridors along Castle Creek and the flanks of Round Mountain to accommodate seasonal big game migration.
- Conservation corridors; should be a minimum of 600' in width in wooded areas and 1200' in open grass/shrub areas.
- Conserve smaller internal washes with conservation corridors 100' _ 200' in width to accommodate daily wildlife movement and protect wash banks.
- Limit the number of residential access road crossings on all major drainages and secondary washes.
- Install low water road crossings at wash locations or use box culverts large enough to allow passage of reptiles and small mammals.
- Require reseeding of road cuts and fills with native species during the first planting season after construction (generally in the fall) to minimize the spread of exotic species like cheatgrass and thistle.
- Restrict fencing to the immediate area around the home site (see below).
- Large lots (240 acres minimum) with conservation deed restrictions.
This alternative would be best suited to the upper two thirds of the site.
Conservation covenants:- A general building zone (150' + radius) is identified for a home site and other out buildings on the 240 acre or larger parcel. The building zone would be outside patches and corridors previously designated as critical wildlife habitat.
- Limit the area within the building zone that could be disturbed for landscaping, generally an area large enough to "fireproof" the structures (see The Wildlife Survival Guide, Gilmer 1995). Note: The size of a fireproof zone is typically large enough to create a landscape plan in scale with a large residence.
- Fencing (if desired) would be limited to the outer periphery of the building zone. (Some owners may wish to "deer proof" their ornamental landscape.)
- Prohibit livestock grazing.
- Limit modification of vegetation outside the building zone to weed
control and habitat enhancement.
In essence the home owner would agree that most of the land he/she purchases would remain undisturbed, a personal wildlife preserve. Wildlife would be free to move between properties because only a small area may be fenced. This approach to development with conservation goals is being used successfully in Washington state and elsewhere in the west.
- Small Lot/Cluster Development; this alternative seems best suited to some
areas within the lower one third of the site near existing developed
properties.
- A general building zone is identified for residential clusters. The building zone would be outside patches and corridors designated as critical wildlife habitat.
- thru D. The same set of restrictions as recommended for large lots, but they would be applied to each cluster of residential units.
It is important to note that although this report and its recommendations emphasizes the conservation of wildlife within a development context, these conserved areas would perform many other useful functions including: erosion control, wash stabilization, increased rainfall infiltration and aquifer recharge, longer periods of in-stream flow, reduced flooding, and enhanced visual quality. In addition, the recommended restrictive covenants would ensure landowners that the character of the areas conserved for wildlife would not change beyond modifications associated with natural plant succession.
Suggestions:
- Encourage landowners to hire a consulting biologist to work with them in identifying a designated building zone that meets their desires and minimizes impacts to wildlife.
- Restrict outdoor lighting during the winter months.
- Encourage underground placement of power and phone lines.
- Encourage the installation of several raptor perch poles (taller than power poles) if power and phone are not placed underground.
- Establish a leash law for dogs during the winter months.
- Encourage owners to provide a small, but permanent source of water for wildlife outside the designated building zone.
Under either of these development alternatives, additional options are possible.
- Non-profit organizations could purchase the most critical wildlife habitat areas and manage them as habitat reserves or turn them over to UDWR to manage.
- Landowners could sell or deed conservation easements to the UDWR on the property outside the designated building zone that would be managed as wildlife habitat.
- All landowners (through an association) could own in common the property outside designated building zones and contribute financially to its management as wildlife habitat by a contracting management group.
The option with the highest probability of conserving the north La Sal mule deer population would be to swap the SITLA Castle Valley property with the BLM or UDWR for BLM or UDWR property of equal value elsewhere in the region. Federal or state ownership and agency management would close the "keyhole" and permit unified habitat and wildlife management across upper Castle Valley. However, given the unique amenities of this site an equitable swap may be difficult.
These are general guidelines that, if implemented and rigorously enforced, would reduce the impacts to wildlife associated with development of the SITLA property in Castle Valley. Additional measures that can further reduce impacts are possible through specific site plans for the development and the detailed landscape plans for individual homes or clusters of dwelling units.