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CNHP Biological Assessment |
a scientific basis for conservationIn 2005 the Land Trust commissioned a comprehensive Biological Assessment of the Baca Grande and its four major riparian corridors with a $48,000 grant from the Colorado Division of Wildlife. The study was conducted by John Sovell, zoologist with the prestigious Colorado Natural Heritage Program affiliated with Colorado State University at Ft. Collins. To download a pdf of the Sovell Report, <click here> Summary of the Biological Survey To assist the Crestone community with its desire for environmental stewardship, the Colorado Natural Heritage Program (CNHP) was contracted by the Crestone Baca Land Trust to perform a biological assessment of the Baca. The purpose of this assessment is to identify important biological resources and assist the Land Trust with identifying focal areas for conservation action, and to offer recommendations on development that will benefit preservation of the Baca’s biological resources. During summer 2005, almost every area of the Baca was visited once, and in some cases multiple times, to search for rare animals and record the type and condition of plant communities of concern present on the Baca. Survey sites were visited at the appropriate time as dictated by the seasonal occurrence of the individual animal species. The results of the Baca survey confirm that there are numerous animal species and one plant community of conservation priority within the Baca. Several uncommon and even rare species of animals (5 in all) inhabit the Baca. In all, 45 different animal species were recorded from the Baca. Other species of interest on the Baca include elk and pronghorn, which are still wide-ranging and common, but are considered important for aesthetic reasons.
We have delineated five potential conservation areas and one site of local significance on the Baca where conservation is a desirable priority (see above map). These areas include the riparian corridors at intermediate elevations along all four creeks passing through the Baca, which support occurrences of the vulnerable narrowleaf cottonwood and Rocky Mountain juniper Woodland plant community. Future residential development, road construction, and recreational activities in and near these occurrences run the risk of compromising the health of these unique woodlands, which are currently in fair to good condition. These riparian woodlands sustain a wealth of biological diversity including a diverse community of riparian woodland birds, which indicates that the riparian hydrology is intact and functioning. Maintaining the natural hydrology will be difficult in the face of the development occurring in the Baca, but is important if health of the riparian corridor and riparian dependent species are to be maintained. Development of the water resource potential of the Baca to meet an expanding human population will make this difficult, but not impossible. Conservation of these riparian communities is an important management priority and should be a component of any future activities on the Baca. Also included are lands supporting a population of the vulnerable agrestis subspecies of the northern pocket gopher, which is concentrated along the riparian corridors at lower elevation. Conservation of this population of gophers is also a management priority and should also be a component of any future activities on the Baca. Finally, there is one area where Spanish Creek crosses Camino del Rey, which includes a pond and wetlands that supports a diverse number of aquatic dependent animals. Protecting this wetland from future disturbance will benefit these wetland dependent animals and enhance the character of the Baca for current and future residents. It is a remarkably rich biological habitat, with Brazilian free-tailed bats, tiger salamanders, chorus frogs, mountain plover, and Wilson’s phalaropes. The CNHP biologists recommend against development adjacent to this pond and its surrounding wetland. Human presence, in the form of polluting septic systems or nearby traffic by automobiles, could have disastrous consequences on its fragile ecosystem. Judging from algae bloom in the waters, there already is some pollution in its waters, probably by up-stream septic systems. Specifically, the report discourages additional septic systems in the area unless there can be guarantees that they will not pollute the streams. Using mist nets, John Sovell found Brazilian free-tailed bats near the pond. These bats are extremely rare with only 17 recorded occurrences. In Saguache County, there are three records for Brazilian free-tailed bat populations, and one is from the Baca. The Brazilian free-tailed bat commonly roosts in caves and mines and is very social, with huge nursery colonies. The colony at the Orient Mine has an estimated population of as many as 250,000 individuals and is the largest colony in Colorado. The bats found in the Baca were probably foraging individuals from the Orient Mine, making this wetland an important source of food and water for the colony. The Brazilian free-tailed bat moves far beyond the Baca and travels south to Mexico and Central America for the winter. Populations of this bat are thought to be in decline, a decline apparently caused by disease, pesticide poisoning, and human disturbance of nursery colonies. These bats are truly our friends, as they feed on mosquitoes, as well as moths, flying ants, and beetles. Sharing the wetlands with the bat is the mountain plover. There are only 115 records of this globally imperiled bird. In general, the lands delineated by these six areas are in fair to good condition with their natural hydrology still intact, and their plant communities are supporting an abundance of wildlife, including species of conservation priority. Elk and pronghorn also occupy the Baca and their continued viability will require maintaining corridors of connectivity between the Baca and public lands to the east, west, and south. Large open areas must also be left undisturbed within the Baca to provide areas for the pronghorn and elk to browse and graze. Management activities that will benefit the riparian corridor include maintenance of the natural hydrology, prevention of residential development and the placement of septic systems near streambeds, and implementation of an integrated weed management plan. Appropriate planning for residential development to avoid loss of vegetation within and near the riparian corridor and to prevent nutrient enrichment of the creeks from septic systems and residential gardens and lawns would benefit health of the riparian communities within the Baca. Recommendations of the Biological Survey 1. Develop and implement a plan for protecting the biologically significant sites that are profiled in the report. The most significant areas of the Baca are the four riparian corridors, which cut across the community from east to west: Crestone, Willow, Spanish, and Cottonwood Creeks. Because they have unique biology, they are in need of priority attention. Consider incentive-based programs such as purchasing development rights or outright purchase from willing owners of land for significant sites that are in need of protection. Support local organizations, such as the Baca Crestone Land Trust, in purchasing or acquiring conservation easements for protection of biological diversity or open space. Explore opportunities to form partnerships to access state and federal funding for conservation projects, such as those offered through the Colorado Division of Wildlife. 2. Use this report in the review of proposed activities in or near these sites to determine whether or not activities adversely affect elements of biodiversity. All of these sites contain elements of biodiversity of state or global significance. Certain land uses on or near a site may affect the element(s) present there. Range-restricted species may be especially vulnerable to habitat destruction, while wetland and riparian areas are particularly susceptible to impacts from off-site activities if the activities affect water quality or hydrologic regimes.
3. Recognize the importance of larger, contiguous plant communities. While the sites identified in the report contain known locations of significant elements of biological diversity, protection of large areas in each vegetation type, especially where these are connected, may ensure that species that have not yet been located are not lost. Work to protect large blocks of land in each of the major vegetation types in the Baca, and avoid fragmenting large natural areas unnecessarily with roads, trails, etc. Large migrating animals like pronghorn and elk are part of our biological diversity, and their needs for winter range and access to protected corridors to food and water should be taken into consideration. Fragmentation of the landscape also affects smaller animals and plants, opening more edge habitats and introducing exotic species. 4. Increase efforts to protect biodiversity by promoting cooperation and incentives among landowners, pertinent government agencies, and non-profit conservation organizations. Involve all stakeholders in land use planning. The long-term protection of biological diversity in the Baca will be facilitated by the cooperation of the POA, private landowners, businesses, government agencies, and non-government organizations. Efforts to provide stronger ties among federal, state, local, and private interests involved in the protection or management of natural lands will increase the chance of success. 5. Promote wise management of the biodiversity resources. Development of a site-specific conservation plan is a necessary component of long-term protection. Because some of the most serious impacts to ecosystems are at a large scale (e.g., altered hydrology, residential encroachment, and non-native species invasion), considering each area in the context of its surroundings is critical. With the current rate of population growth in the Baca, rare and imperiled species and plant communities may precipitously decline if not given appropriate protection or management attention.
6. Stay informed and involved in public land management decisions. The Baca Grande is surrounded on three sides by federal public lands including the Great Sand Dunes Nation and National Park and Preserve, the Baca National Wildlife Reserve, or U.S. National Forest property. Encourage protection for the most biologically significant sites by implementing within the Baca Grande compatible management activities designated in National Park Service Plans and U.S. Fish and Wildlife Service Plans. 7. Continue to take a proactive approach to weed and exotic species control. Recognize that weeds affect native plant communities and other plant and animal species. Discourage the introduction and/or sale of non-native species that are known to significantly impact natural areas. These include, but are not limited to, exotic, invasive species such as tamarisk, Russian olive, dalmation toadflax, purple loosestrife, and non-native fish species. Further, natural area managers, public agencies, and private landowners should be encouraged to remove these species from their properties. Enforce the use of weed-free forage on horse trails. Encourage the use of native species for revegetation and landscaping efforts. Ideally, seed should be locally harvested. This includes any seeding done on POA road right-of-ways. 8. Develop and implement a fire management and mitigation strategy for riparian corridors. In lower montane riparian corridors fires are presumably uncommon due to the high moisture content of riparian soils and vegetation, and the low frequency of lightning strikes in low-lying drainages and valley bottoms where riparian areas occur. Historically, in lower montane riparian woodlands low intensity surface fires occurred about once every 25 to 50 years and consequently, compared to drought, fire is less important to these riparian systems. Although it is the least vigorous sprouter of all the cottonwood, narrowleaf cottonwood probably resprouts following light intensity fires and mature narrowleaf cottonwood trees may resist fire, but young trees are probably killed by fire, and older trees are commonly killed by even relatively cool fires which wound trees and facilitate the onset of heartwood decay. When fire removes competing conifers, thins the overstory, allows more light penetration, and exposes the mineral soil, it allows cottonwood seeds to establish if soil moisture is adequate. In areas where conifers are taking over the riparian corridor, if fire does not occur the cottonwoods may be lost. The thinning of junipers in areas where dense stands have taken over the narrowleaf cottonwood -Rocky Mountain juniper woodland will help maintain this plant community. Also, the thinning of shrub cover and young juniper, where dense stands of shrubs and junipers exist in the understory of the riparian woodland, will help to reduce fuel loads and remove ladder fuels that could result in the loss of larger cottonwoods and junipers in the event that a fire does occur. This would also open areas where young cottonwoods could regenerate if soil moisture is adequate. |
view from the Oxbow Wetlands, south toward Blanca Peak.
© Linde Waidhofer