BL / ENVS 448 Plant Biodiversity and Ecology

Plant Communities of the Rocky Mountains

What are plant communities?

• Often defined by major plant species / types

• Temperature and precipitation prevail

• Altitude determines the above

• Several types in Colorado

• From lowest (and hottest) to highest (and coldest)

Desert and semi-desert

• Mainly canyon country in the western part of the state

• Less than 14 inches of rainfall

• 4,000 to 6,500 feet in elevation

• Lower areas dominated by shrubs like rabbitbrush and sagebrush

• Higher areas dominated by Pinyon Pine and Juniper

Rabbit brush and Pinyon Pine

Moving on up - Grasslands

• Dominated by grasses

• 3,500 to 6,500 feet

• More precipitation (about 20 inches)

• Eastern third of Colorado

• Can still find some sagebrush and rabbitbrush and cactus, but many more mixed grasses

• Tall grass and short grass in Colorado

Grasslands

Bouteloua sp. Grasslands

Big Will and Will J. in tallgrass

Prickly Pear amongst the grasses

Foothills

• Includes mesa tops

• 6,500 to 8,500 feet

• Ponderosa pine, still some pinyon and juniper

• Oak thickets (we only have one Gambel’s)

• Mountain mahogany

• 14 to 25 inches of precipitation

Foothills

Inspiration Point – sagebrush and P.J.

Will J. enjoying the foothills

Bobcat in the foothills

Montane

• Forest• Mixed conifer and aspen (most wide

ranging tree in U.S.) • 8,000 to 10,000 feet• Understory vegetation is mostly shrubs• Willow shrubs in riparian areas• 18-30 inches of precipitation• ¼ to ½ as snowfall

Montane Forests

Pentaphylloides floribunda aka Rocky Mountain Cinquefoil

Penstemon whippleanus

Aquilegia caerulea

Subalpine

• Thick spruce/fir forests

• Aspens only in lower elevation here

• 25-40 inches of precipitation a year

• Last zone before alpine

Hard at work in Breckenridge

More hard work in the montane

/subalpine

Mertensia ciliata mountain bluebell

Castilleja rhexifolia X miniataIndian paintbrush

Chaemerion danielsii

Alpine

• Alpine tundra (not arctic tundra)

• Dwarf shrubs, herbs, and cushion plants

• Above treeline (about 11,500 feet in CO)

• 30-55 inches of moisture

• Most as snowfall

Above the trees

Big horn sheep

Eritrichium aretoides alpine forget-me-not

Gentiana parryi - Parry’s gentian

Silene acaulis – moss campion

TROPICAL ALPINE Azorella compacta