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PLANTS AND ANIMALS IN HIGH PLACES: The Alpine Ecosystem in Utah

This is a reprint of an article written for the June l997 issue of the Newsletter of the High Uintas Preservation Council (soon renamed the LYNX) by HUPC member Dr. Richard Shaw, Professor Emeritus and Emeritus Director of the Intermountain Herbarium, Department of Biology, Utah State University. Dr. Shaw’s fine illustrations are from his book, Vascular Plants of Northern Utah, USU Press, 1989 and appear here courtesy of USU. Read the review of this essential book in our archives (see page ten of this issue) to further enjoy a vicarious, floral visit to the high country, courtesy of Richard Shaw! Editor

What is an alpine ecosystem? Simply stated it is a solar energy driven system of plants and animals that is self-sustaining in a high mountainous environment too severe to meet the requirement for tree growth....
“Upper or alpine treeline” applies to the upper elevational limits of forest and tree growth. The alpine treeline of the Utah mountains does not form an abrupt boundary but usually forms a transition zone varying from 9,500 to 10,000 feet, depending on a series of environmental factors. Alpine treeline has a diversity of interacting causes affected by indequate summer temperatures; thus it is classed as a “cold treeline....”

In this commentary we will emphasize the summits over 10,000 feet. The National Geographic Names Data Base lists 263 summits. This is quite a staggering figure as one considers a map of Utah. The Wasatch and Uinta Ranges stand out as the ranges with the most number of peaks; the latter is the largest mountain range with 39 summits over 10,000 feet. It also has the distinction of being the largest range in the western hemisphere that extends in an east-west direction (Fenneman l931). This massive Uinta Range is 150 miles long and 35 miles wide, and its highest summit is Kings Peak at 13,498 feet. The upper portion of the range has been heavily glaciated leaving scooped-out cirque basins. The Uintas have a floristically rich alpine flora above 11,000 feet, which extends along the crest for 60 miles and covers more than 300 square miles (Cronquist et al l972).

Alpine Flowers by M. PettisA person climbing upslope on any of these mountains will pass through the alpine treeline and note that trees become increasingly stunted and are finally reduced to shrub-like forms. This is often referred to as the “krumholz line.” The term “krumholz” (German for “crooked wood” ) is used for the environmentally dwarfed forms of species that become treelike in less harsh environmental sites.

This challenging environment beyond the krumholz appears at first glance to be a cold inhospitable desert; but, in fact, it will, reveal a wealth of miniature plants as well as some uniquely adapted interacting animals. When examined with patience, the smallest plants express themselves in a number of growth forms with incredible evolutionary ingenuity. They are truly beautiful and remarkable, and they thrive amid stressful environmental forces of low summer temperatures, buffeting winds, drought, intense ultraviolet light and soil churning processes caused by frost and burrowing animals.

Lakes and streams are common in the alpine zone but no aquatic species are likely to be found. Bogs, however, generally occur close to the lower limits of the alpine zone at 9500 feet. Alpine plants commonly occur in glacial cirques and local depressions in the major canyons especially along streams. Sedges, grasses and willow species dominate the vascular flora. others species found in bogs include elephanthead (Pedicularis groenlandica), redpod stonecrop (Sedum rhodanthum), and alpine laurel (Kalmia polifolia).

The bog habitat usually grades into wet meadow habitat, and these are common at lower elevations in the glacial cirques. Vegetation surviving below slow melting snowbanks is also included in this habitat type. Wet meadows are usually dominated by marshmarigold (Caltha Leptosepala). American bistort (Polygonum bistortoides), alpine speedwell (Veronica wormskjoldii), and sedge species. Along streams parry primrose (Primula parryi), pretty paintbrush Castelleja pulchella), and explorer gentian (Gentiana calycosa) are apt to be found. Ground which is exposed by late melting snow usually supports species such as springbeauty (Claytonia lanceolata), glacier lily (Erythronium grandiflorum), and alpine buttercup (Ranunculus adoneus.)

Dry meadows are fairly common and perennial species of the sunflower, pea and grass families are likely to dominate. Alpine hymen-oxys (Hymenoxys grandiflora), dwarf clover (Trifolium nanum), and spike trisetum (Trisetum spicatum) are frequently seen herbaceous plants.

Talus, scree and boulder fields are called debris accumulation sites. These habitats are often physically disturbed by mass movements. Plant cover here is usually very low. However, many species have adapted to the disturbed and dry conditions by producing extensive root systems. Common species included mountain avens (Dryas octopetala), mountain sorrel (Oxyria digyna), brittle fern (Cystopteris fragilis), and sticky jacobsladder (Polemonium viscosum).
Rock faces and cliffs are abundant and climbers are greeted by pygmy saxifrage (Saxifraga debilis), Lyall rockcress (Arabis lyallii) and alpine forget-me-not (Eritrichium nanum).

ALPINE PLANT ADAPTATIONS

Alpine Flower by M. PettisConsider just a few of the plant adaptations, and it will be apparent that they generally involve characteristics that are responsive to environmental conditions of temperature, light, moisture, etc. Most of these adaptations are genetically controlled; and, therefore, persist even if the plant is moved to another habitat.

More than 99% of alpine plants are perennial; and, thus, they do not have to expend the metabolic energy necessary to produce stems, leaves, flowers, and fruits in one growing season as seen in annual plants. Growth, however, in the short season is slow and many species may be eight to twelve years old before they flower. Alpine perennials have winter buds protected well below the soil surface in contracts to trees that have winter buds well above.

Cushion plants such as alpine forget-me-not (Eritrichium nanum) show a distinctive low growing aspect and are the ideal pioneers in windy areas. Their low growing shape favors the wind to flow easily over them as over an airplane wing. Because of their compactness, temperatures may be several degrees higher in a cushion plant than outside.

Another cushion plant species, moss campion (Silene acaulis), has such short dense branches and leaves that it can catch and hold wind blown soil and moisture, contri-buting to soil building and stabilization. A cushion plant the size of a saucer may have a four or five foot taproot seeking deep moisture and anchoring the plant against the constant wind.
Many alpine plants have various coatings of hairs: long and soft, tangled, felty, star-shaped and often glandular. These hairs protect the plant’s stomata, the pores in the epidermis which allow the exchange of gases so necessary for photosynthesis and respiration. The hairs are also capable of shading and protecting the delicate photo-synthetic cells of the inner leaf from the harmful effects of ultra-violet light, and at the same time reduce water loss in this windy region. Look for other adaptations such as succulence of leaves, red pigments and crowded rosette leaf patterns.

ALPINE ANIMAL ADAPTATIONS

Bumblebees, butterflies and hummingbirds have long been recognized as visitors to alpine flowers, but only recently has it been shown that muscoid flies are also important in the movement of pollen. Several alpine flowers are shaped like solar reflectors. Temperatures inside these flowers have been measured at 12- 14 degrees F. above the surrounding air temperatures. Muscoid flies frequent such flowers; and, thus, they can begin their daily foraging earlier. Flower species of Potentilla and Ranunculus are good examples of solar reflectors....

VISITING THE ALPINE ECOSYSTEM

...Alpine plants and animals are “tough.” In their contacts with modern man and his domestic livestock these organisms and their ecosystem are “fragile.” There is little or no carrying capacity in many of these ecosystems to disturbance by people afoot or on horseback. The vegetation is especially susceptible to the impact of countless human feet. Step on rocks where you can and stay on authorized trails. When the vegetation is damaged, the soil suffers. Alpine meadows and bogs are particularly vulnerable, but so are rocky soils on the ridges. Erosion may follow and when the soil is destroyed, so is the alpine ecosystem.



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