Conservation Easements in Colorado’s Front Range

Biodiversity in the Colorado Front Range is a critical component for the sustainable development of the region (Chivian and Bernstein, 2010; Pague, et. al, 1996; Pague, et. al, 1993). Conservation easements (CEs) are one tool used by non-profit groups and government agencies to protect biodiversity. However, establishing CEs is, at times, unpredictable (Axel-Lute, 1999). They are often a result of donated gifts or opportunistic purchases. Therefore, they can lack long-term strategic planning to protect biodiversity (Whittaker, 1999; Daniels and Daniels, 2003). This project used a GIS-based analysis to measure the extent CEs have protected high biodiversity areas from development along Colorado's Front Range. Land trusts, as well as other conservation organizations, can use this information to improve the strategic targeting of CEs to protect biodiversity.

Potential Conservation Areas (PCAs) were used as the focal point to measure the extent CEs protect biodiversity. PCAs are defined as “land areas that can provide the habitat and ecological processes upon which a particular element (i.e. rare plant and animal species and significant plant communities) occurrence, or suite of element occurrences, depends for its continued existence” (Lyon, et. al, 2001). PCAs are ranked according to their biodiversity significance, ranging from 1 (greatest) to 5 (least). This study only analyzed categories 1 to 3.

CEs from six land trusts in Boulder, Douglas, and Jefferson Counties were analyzed within a one mile buffer of PCAs. The percentage CEs comprise each buffer for a PCA is based on the following criteria: very high (Greater than 80%), high (60-80%), medium (40-60%), low (20-40%), and very low (Less than 20%).

Due to the proximity of PCAs, buffers occasionally overlap other PCA buffers. CEs, thus, have the potential to serve as buffers for multiple PCAs. These areas were also delineated, analyzed, and reported separately. Level 1 serves a buffer for one (1) PCA. Level 2 serves a buffer for two (2) PCAs and level 3 for three (3) PCAs. These buffer areas have the potential to serve as wildlife corridors, connecting multiple PCA habitats.

Results can be categorized into two areas: Buffer percentages for PCAs and buffer percentages for multiple PCAs. The former reveals the majority of CEs provide little coverage of the total land available for protection within PCA buffer zones. This conclusion was anticipated by the author due to many factors, notably the large presence of public land in the study region and the difficulties associated with pursuing a strategic approach to CEs.

As for the latter, results reveal buffer areas adjacent to two or more PCAs can potentially act as wildlife corridors, with CEs providing sufficient coverage. This was an unexpected, and valuable, outcome of the analysis.

Table 1 demonstrates land trust CEs adequately protect these areas in relation to the available land for protection. With the exceptions of Biodiversity 1 Level 2, Biodiversity 2 Level 2, and Biodiversity 2 Level 3, land trust CEs provide substantial coverage in overlapping buffer areas. Where land trust CEs are deficient or absent, notably Biodiversity 2 Level 2 and Level 3, public land comprises a majority of the buffer area. See Figures 1 and 2 for illustrative examples.

Figure 1 depicts two examples of land conservation easements (red) creating a buffer (black line) for multiple PCAs (purple). Areas shaded blue and yellow illustrate private and public land, respectfully.

Figure 1: Land Conservation Easements Creating a Buffer for Biodiversity 3 Level 2 (left) and Biodiversity 3 Level 3 (right)

Figure 2 depicts two examples of public land (yellow) creating a buffer (black line) for multiple PCAs (purple) where land conservation easements are absent.

Figure 2: Public Land Creating a Buffer for Biodiversity 2 Level 2 (left) and Biodiversity 2 Level 3 (right)

References

Axel-Lute, Miriam. 1999. A meeting of movements. Shelterforce, no. 103. http://www.nhi.org/ online/issues/103/axellute.html (accessed September 4, 2013).

Chivian, Eric, and Aaron Bernstein. 2010. How our health depends on biodiversity. Boston, MA: Center for Health and the Global Environment, Harvard Medical School. http://www.cbd.int/doc/health/health-biodiversity-hms-en.pdf (accessed March 19, 2014).

Daniels, Tom and Katherine Daniels. 2003. The environmental planning handbook for sustainable communities and regions. Chicago, IL: APA Planners Press.

Lyon, Peggy, John Sovell, and Joe Rocchio. 2001. Survey of critical biological resources Garfield County, Colorado. Fort Collins, CO: Colorado Natural Heritage Program. http://www.cnhp.colostate.edu/download/documents/2001/1_Garfield_Co_full_report.pdf (accessed September 25, 2013).

Pague, C.A., A.R. Ellingson, S.M. Kettler, S.C. Spackman, J. Burt, and K.D. Essington. 1996. Natural heritage resources in Douglas County and their conservation. Fort Collins, CO: Colorado Natural Heritage Program. http://www.cnhp.colostate.edu/download/documents/1996/Douglas_County_Inventory.pdf (accessed August 3, 2013).

Pague, C.A., Renee Rondeau, and Mark Duff. 1993. Natural heritage inventory of Jefferson County, Colorado. Fort Collins, CO: Colorado Natural Heritage Program. http://www.cnhp.colostate.edu/download/documents/1993/Jefferson_County_Inventory.pdf (accessed August 2, 2011).

Whittaker, Marci. 1999. Preserving open space on the rural-urban fringe: The role of land trusts. In Contested countryside: The rural-urban fringe in North America, edited by O. Furuseth and M. Lapping, 268-89. Brookfield, V.T.: Ashgate Publishing Company.