Some aspects of the natural history of Colfax and eastern Taos Counties, New Mexico
— William C. Martin

The Colfax County-eastern Taos County area of New Mexico is of vital interest to biologists and students of natural history because of its location relative to the flora and fauna of the southern Rocky Mountains and the Great Plains as well as the rather significant differences in elevation within the area. Elevations range from about 5,800 ft in the southeastern part to 13,160 ft at the summit of Wheeler Peak in the eastern part of Taos County, this being the highest peak in New Mexico.

The eastern one-third of the study area is bisected roughly north to south by a major stream, the Canadian River, which drains this portion of northern New Mexico as well as a small part of southern Colorado. The Canadian River receives the water of the Vermejo River, a much smaller stream which begins in the northwestern part of Colfax County in the vicinity of the 12,634 ft Costilla Peak, just south of the Colorado-New Mexico border.

 

Extensive stretches of the eastern, southeastern, and southern parts of Colfax County are an extension of the Great Plains and are represented for the most part by a shortgrass prairie with a flat to rolling topography broken here and there by small ranges of mountains or by hills, these typically not exceeding 9,000 ft in elevation.

The western part of the Colfax County-eastern Taos County area is mostly very mountainous, the higher elevations culminating in several peaks exceeding 12,000 ft. Areas above the 12,000 ft level support an alpine-tundra type vegetation as well as certain faunal species adapted to these higher elevations. The elements of the natural history of the western part of Colfax County and eastern Taos County are strongly influenced by the ecological conditions prevailing in the Sangre de Cristo Range, a part of the southern Rocky Mountain System. 

The only significant body of water found in the study area is Eagle Nest Lake, a reservoir located just south of the resort town of Eagle Nest at an elevation of about 8,500 ft.

As is true throughout the Southwest, the amount and distribution of precipitation are important factors in the development, diversity, and maintenance of the flora and fauna. Although precipitation is not really abundant anywhere in the southwestern United States, this part of New Mexico usually receives a greater amount of precipitation than do areas to the south and southwest. Mean annual precipitation ranges from 16 to 20 in. with relatively heavy winter snows and summer rainfall in the form of frequent afternoon thundershowers, especially in more mountainous areas.

Mean temperatures range from a low of 0-12°F and a high of 32-44° in January to a low of 40-44°F and a high of 80-84°F in July.

 

Certain vegetation zones are clearly marked in this area and their designation is based primarily on vegetational and altitudinal criteria. These zones include shortgrass prairie, pinyon-juniper, mixed conifer, spruce-fir, and alpine-tundra associations, each of which contains certain characteristic plants and animals.

 

In order to approach the discussion in a systematic fashion, the material is presented in terms of the flora and fauna characteristic of each major floristic association beginning with the shortgrass prairie at the lower elevations and proceeding step by step to the alpine-tundra located above treeline.

 

A map of the area (Fig. 1) presents a general idea of the extent and location of the associations under discussion. The map also indicates the position of major topographic features and their approximate elevations as well as other pertinent points of reference. A diagrammatic cross sectional view of the east-west axis of Colfax and eastern Taos counties (Fig. 2) shows the vertical relationships of the associations and briefly summarizes some important biological characteristics of each association.