Tuesday, March 30, 2010

A Colorado Jewel: Southeastern Prairies and Canyonlands

A Regional Perspective

The Central Shortgrass Prairie (CSP) ecoregion covers 56 million acres across seven states. Grasslands are among the most highly altered of all ecosystems worldwide, and this is true in the CSP ecoregion as well. The one exception is the southwestern portion of Colorado's eastern plains, where native grasslands, juniper savannas, and canyons still retain much of their historic integrity and support many species of conservation concern. Many conservation organizations and government agencies have documented the significance of this intact landscape for conservation of declining prairie species.

The Prairies: grasslands and the species they harbor

Colorado has lost roughly 48% of its historic native grasslands - a loss rate that is more than twice as high as that experienced by any other large-scale ecological system in the state. The remaining grasslands cover about 22% of Colorado, but are significantly under-represented in the state's portfolio of legally protected landscapes. With the exception of wetland and aquatic habitats, grasslands support more than twice as many animal species of concern when compared to other habitats, including forests and shrublands, which both cover approximately the same percentage of land as grasslands (roughly 19-21%). Grassland habitats are particularly important for birds and mammals.

Canyonlands: it's all about the water

The canyon topography of southeastern Colorado is unique in the prairie ecosystem, and supports juniper woodland and savanna communities that provide very distinct habitas. The hydrologic system around the Purgatoire is the least altered of all plains river systems. Plant and animal communities in this system are much healthier and more diverse than those found in any other hydrologic system on the plains. The region's canyonlands are a state hotspot for rare ferns, and contain one of the highest concentrations of plains leopard frogs in the state.

Some of Colorado's Rarest Plants

The worldwide distribution of four plant species is restricted to barrens habitats in and near the study area. Land management in this region will determine the fate of these species.

The Ranching Legacy and Future Management

In stark contrast to the remainder of Colorado, the vast majority of the state's eastern plains are privately owned, with agriculture forming the basis of local economies. With the loss of the prairie's most significant native grazer - the bison - cattle grazing has become a crucial ecological process for maintaining habitat conditions on the prairie. The number of places supporting species and habitats of conservation concern is testament to the on-going stewardship of Colorado's ranching families. The future of our prairie ecosystem rests in their hands. In order to maintain the current level of ecosystem integrity and species health, it will be crucial for future management of the rangelands to ensure:
  • healthy blue grama communities,
  • an intact hydrological regime, and
  • a mosaic of grass, shrub, barren, and woodland/savanna patches to provide for the varied needs of all native prairie inhabitants.

Survey Results

During the summers of 2007 - 2009, the Colorado Natural Heritage Program's biologists and partners surveyed 26 private ranches in southeastern Colorado. Researchers documented 123 species and plant communities of conservation concern, including 41 animals, 36 plants, and 46 communities. To date, these species and communities have been documented at over 2,400 of discrete locations across the landscape. Future surveys would undoubtedly document additional locations.

This project was a collaborative effort among southeastern Colorado's private landowners and biologists from the Colorado Natural Heritage Program, Denver Botanic Gardens, Rocky Mountain Bird Observatory, and Colorado State University's Larval Fish Laboratory. For more information, please see our reports page. The above text, with more great pictures and graphics, is also available as a brochure.

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