WSP04503

• File Number: 8142.600.20
• Description: Trinidad Project - Environmental Studies
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 3/1/1974
• Author: Corps of Engineers
• Title: Draft Environmental Statement - Trinidad Lake Project - Purgatoire River - Colorado
• Water Supply Pro - Doc Type: Report/Study

pine is dominant and averages about 15 feet tall. A few open parks

are scattered throughout the woodland. Height and density of the

woodland is significantly influenced by exposure, increasing on

slopes with a northern exposure and decreasing on slopes with a

southern exposure. The more common understory growth include:

grasses - blue and sideoats grame, Indian rice grass, three-awn,

little bluestem, western wheat grass, and ring muhly; forbs.-- flea-

bsne, wild onion, and penstemin; woody shrubs -- mountain mahogany,

Gambel oak, soapweed and serviceberry; cacti -- prickly pear and

cholla. Understory vegetal is generally sparse to moderate. This

association has also been subject to grazing and other uses for many

years.

Floral species characteristic of the higher Transition Zone

(ponderosa pine) occasionally intrude into the pinon-juniper wood-

land, especially along watercourses where there is an inversion of

the normal altitudinal distribution. West and north of the pinon-

juniper woodland, elevations increase and, correspondingly, precipita-

tion increases and the Upper Sonoran Life Zone of the Trinidad area

merges with the Transition, which, in turn merges with the Canadian

and on up into the Arctic-Alpine.

b. Terrestrial fauna. The pronounced diversity of habitat

among the mountains, river valley, and plains reflects the patent

ecological variety to be found in Las Animas County and within the

general project area. Mountains and plains support faunas that are

largely distinct from one another. The ecotone (transition zone)

between mountains and plains has a fauna derived in part from contiguous

11-20

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