species, including Ranunculus nivalis, Salix herbacea, S. polaris, Sib- 

 baldia procumbens, and Saxifraga spp., are found at lower ele- 

 vations in the conifer and birch zones in certain places such as 

 river banks, inundated lake shores, talus slopes, paths, and old 

 reindeer pens {Phippsia algida in the last), where the environ- 

 mental requirements of alpine plants, including nonpodsolized, 

 nutrient-rich soil and exposure to sunlight, can be supplied, and 

 competition with subalpine plants is reduced or absent. •'' There- 

 fore it appears that the ecological success of alpine plants is at- 

 tained by their efficiency in using the resources of their environ- 

 ment in a short growing period and in the absence of competi- 

 tion with other species. 



In the reseeding of range lands, in the introduction of new 

 crops into a region, and in biological control it is important to 

 evaluate the opportunities for ecological success of ecotypes, 

 varieties, and species that may be used. This includes considera- 

 tion of their characteristics, particularly the requirements, eco- 

 logical amplitude, and competitive capacity. The use of the 

 homocHme technique' ^2 {^ also helpful in the introduction of 

 new species because it stresses the selection of plants or animals 

 from areas of similar environmental conditions. It has been shown 

 that when a strain grows well in one place, such as in a certain 

 area of California, it will be successful in other areas that are 

 similar in latitude and cHmate such as parts of Israel, provided 

 that diseases, parasites, or competition are not limiting factors. 

 In order to reduce competition it may be necessary to destroy most 

 of the dominant plants in an area before introducing a species 

 from another region. 



GENERAL REFERENCES 



Billings, W. D., "The Environmental Complex in Relation to Plant Growth and 



Distribution," Quart. Rev. BioL, 27, 251-264 (1952). 

 Daubenmire, R. F., "Plants and Environment, a Textbook of Plant Autecology," 



2nd Ed., John Wiley & Sons, Inc., New York, N.Y., 1959. 

 Dice, L. R., "Natural Communities," Univ. Michigan Press, Ann Arbor, Mich., 



1952. 

 Heslop-Harrison, J., "New Concepts in Flowering-plant Taxonomy," Harvard 



Univ. Press, Cambridge, Mass., 1956. 

 McDougall, W. B., "Plant Ecology," 4th Ed., Lea & Febiger, Philadelphia, Pa., 



1949. 



58 • Species and Populations 



