Title: Components of adaptive variation in pinus contorta from the inland northwest
Identifier: componentsofadap375rehf (find matches)
Year: 1987 (1980s)
Authors: Rehfeldt, G. E; Intermountain Research Station (Ogden, Utah)
Subjects: Variation biology; evolution; lodepole pine adaptation Northwestern States
Publisher: (Ogden, Utah) : U. S. Dept. of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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Figure 4—Geographic patterns that are independent of elevation as predicted by regression models. Patterns are relative to the distribution of the species (shading), the Bitterroot Range, and the Salmon River. Isopleths are positioned relative to the mean value (x) with an interval scaled to V2/sd (0.05). of relatively equal predicted performance for the mean elevation (1,625 m). Contouring was begun with the mean value, and the interval between isopleths was scaled to Vzlsd (.05). Thus, populations separated by two isopleths are expected to differ at about the 95 percent level of probability. The pattern for late growth duplicates that of 7-year height and is not presented. When comparing populations from the same elevation, those from the north were the tallest and had the most late growth; populations from central Idaho were the shortest and exhibited httle late growth. The percentage of trees infected with needle cast or infested with mites was directly related to the geographic distance that the seed was transferred to the planting site. Populations of highest adjusted heights at Lost Valley (1,500 m) tended to be from the north where growth potentials were highest. DISCUSSION The results illustrate differentiation of populations for numerous traits which together determine adaptedness, the degree by which populations are physiologically at- tuned to their environment. Genetic differentiation was readily detected experimentally, and patterns of genetic variation were closely associated with the elevation and geographic location of the seed source. Pronounced clines tend to typify genetic differentiation in montane popula- tions of P. contorta spp. latifolia (Ying and others 1985; Rehfeldt 1983a, 1985a; Stoneman 1985). That the clines reflect adaptation to natural environ- ments is demonstrated both directly, as differential fitnesi in contrasting environments, and indirectly, as genetic responses that parallel environmental gradients. Thus, in- direct support is provided by the steep elevational clines 7

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