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ECOLOGICAL FACTORS: 



Aerial leaves regularly possess certain specializa- 

 tions. The leaves are normally dark green (often very 

 dark), a trait that enhances heat absorption. Such 

 leaves typically are thick and waxy, thereby being 

 specialized to resist evaporation. However, in 

 certain plants the leaves have hairs that are white or 

 approach that color. Although this might seem to 

 cause undue heat reflection, again the color involves a 

 means of retaining heat. The white color is only a 

 surface coat upon many otherwise black hairs. 

 Therefore, once heat is absorbed (even though some- 

 what inefficiently) the white outer coating reflects 

 heat back into the hair of the plant. For this reason, 

 as environmental temperatures are reduced from the 

 extreme day highs, heat is retained in the plant. 



The extensive root system serves two purposes. 

 First, it is a means of reaching deep water during 

 surface drought periods, especially in the relatively 

 arid rain-shadow sides of mountain tops. Second, it 

 serves the very necessary function of anchorage, the 

 only deterrent to mass movements. However, since 

 roots cannot control landslides, a further adaptation 

 of plant aerial parts is significant. Alpine leaves and 

 stems, more than those of plants in most other areas, 

 act as if they are lubricated; landslides frequently 

 pass over these plants without killing them. 



Certain reproductive adaptations can be related to 

 this environment. Although alpine plants are slow- 

 growing and take a long time to flower, they produce 

 many flowers and many seeds, thus increasing the 

 probability of reproduction. Also, most alpine plants 

 either are wind-pollinated or self-fertilized. The re- 

 striction of pollination by insects is understandable, 

 because there are few flying insects in this windy 

 habitat. 



Some of the functional adaptations are of major 

 importance. The plants are slow-growing because of 

 the short growing season. Perhaps most remarkable 

 are some of the adaptations to cold. Many alpine 

 plants germinate and even flower below a snow cover. 

 For this reason, plants function under conditions of 

 little or no sunlight and of freezing temperature. Al- 

 though the adaptations making this possible are 

 little understood, some of the processes involved 

 have been discovered. The plant fluids contain more 

 nutrient materials than do typical plants elsewhere. 

 This means that there is less water in tissues, hence 

 less likelihood of freezing. Most amazing is the dis- 

 covery that some plants flowering under a blanket of 

 snow can produce some heat. Therefore, in some 



plants we find a condition analogous to the internal 

 heat production of endothermic animals. 



ALPINE ANIMALS 



The ability to move enables many alpine animals 

 to avoid the more rigorous periods of their environ- 

 ment. Such large mammals as elk, deer, bighorn 

 sheep, and mountain lions move to lower altitudes 

 during the winter. At lower altitudes food and shelter 

 are more readily available; the elk, deer, and bighorn 

 feed and live among thickets and the mountain lion 

 preys upon these plant eaters. 



In addition to migration, two other means are used 

 by alpine animals to combat climatic extremes. Ani- 

 mals such as ground squirrels and marmots simply 

 avoid the extremes. Before winter they eat large 

 quantities of food and become exceedingly fat; with 

 the coming of winter they hibernate. However, wea- 

 sels, pikas, snowshoe hares, certain voles, and the 

 mountain goat remain active throughout the winter. 

 In all of these animals, activity is aided by the growth 

 of a denser winter coat. In the pikas and voles, heat 

 loss is minimized by the body's approaching spherical 

 shape and extremities being much shortened. Also, 

 pikas, voles, and weasels spend much or all of their 

 time beneath the insulating blanket of snow. Of these 

 mammals only weasels spend considerable time upon 

 the surface. 



During relatively favorable winter conditions, wea- 

 sels and snowshoe hares become quite active, the 

 weasels looking for prey and the hares for plants. 

 Moreover, it may be assumed that both animals are 

 subject to heavy predation because of their protective 

 adaptation, a white winter coat. On the other hand, 

 the weasel's coat may be an example of camouflage 

 that helps in stalking prey. The completely white 

 coat, except for blackish points on the extremities, 

 allows an animal to blend with its white environment. 



The North American mammal best adapted to 

 alpine conditions is the mountain goat. Its coat is 

 composed of long and short hairs that together pro- 

 vide water and wind resistance. Its hoofs are flexible, 

 pincer-like structures with arched bottoms, features 

 allowing great agility among precipitous cliffs. 

 Therefore, it can obtain food in almost unbelievable 

 places and readily avoid potential predators. 



The commonest alpine invertebrates are insects. 

 Alpine invertebrates as a group have few obvious 

 adaptations for alpine life. They are no diflferent 



