Small Mammal Inventory at Great Sand Dunes National Park and Preserve and Florissant Fossil Beds National Monument, 2003-2004

Valdez, Ernest

Great Sand Dunes National Park and Preserve, and Florissant Fossil Beds National Monument encompass unique geologic features in Colorado. Great Sand Dunes National Park and Preserve (GRSA) is known for its large dunes that were created by winds blowing sand into and across the San Luis Valley to the western base of the Sangre de Cristo Mountains. Stabilized by the mountain barrier and replenished with sand from seasonal winds and spring runoff, these dunes and the surrounding areas provide habitat for a variety of desert and montane organisms, some of which occur nowhere else in Colorado or the world. In fact, some habitats have been isolated long enough to lead to the evolution of distinct geographic forms, such as the Great Sand Dunes tiger beetle (Cicindela theatina) and silky pocket mouse (Perognathus flavus sanluisi). Florissant Fossil Beds National Monument (FLFO) once supported a coniferous forest of giant redwood (Sequoia) trees and lush vegetation that surrounded a large and warm lake. The forest and lake were covered with volcanic debris from several local eruptions that killed most life forms. This debris stopped organic matter from decomposing rapidly and, over time, mineral deposits replaced the organic matter. After organic materials became petrified, they were exposed through land upheaval and erosion. This once tropical-like habitat is now replaced by montane meadows and scattered stands of coniferous forests. In an effort to gather valuable biological information, the National Park Service (NPS) initiated a nationwide program to inventory vascular plants and vertebrates on NPS lands. The U.S. Geological Survey, Fort Collins Science Center, Arid Lands Field Station became cooperators in this effort during 2003 and began a two-year mammalian inventory on two parks within the NPS Rocky Mountain Region: the then Great Sand Dunes National Monument, now Park and Preserve, and Florissant Fossil Beds National Monument. Existing baseline data on occurrences of mammals in these parks varied from very little at FLFO, to extensive at GRSA. However, in many cases, information was insufficient to assess the status of species of local concern. Over the last decade the status of small mammals has gained more attention. The 2003 listing of endangered, threatened, and wildlife species of concern in Colorado (http://wildlife.state.co.us/WildlifeSpecies/SpeciesOfConcern/), also emphasizes smaller species such as bats and rodents, mainly because of restricted ranges or lack of information on distribution and natural history. Overall, little is known about the status and trends of these species and whether conservation efforts are needed.

Small Mammal Inventory at Great Sand Dunes National Park and Preserve and Florissant Fossil Beds National Monument, 2003-2004

Collections