Abstract

Adaptive optimality of local populations is central to evolutionary biology. It also provides a genetic framework for planning Gene conservation. We examined local optimality using 20-year height growth as an indicator of population fitness. The height growth data were obtained from a network of 57 long-term field trials in interior British Columbia involving a range-wide samples of 142 lodgepole pine (Pinus contorta Doug) populations. Local optimality was defined statistically and tested, and its geographic patterns were examined in both multi-dimensional mode and component dimensions along latitude, longitude and elevation. Fitness values of local and optimal populations were derived by fitting population variation to response functions for individual sites. Local optimality was an interval estimate, i.e. within the 95% confidence limit of the projected fitness value of the optimal populations. Both biological and physical distances between local and optimal population were used to examine geographic pattern of local optimality.Study leads to following key results: (1) local optimality prevails at majority of sites; (2) populations at northeast bordering the northern Rocky Mountain Trench are most local optimal, whereas non-local optimality most evident along the eastern foothills of the Coastal Mountains in the coast-interior transition climate zone and the high mountains in the southern interior; (3) there is a geographic cline oriented from southwest to northeast, but with a steep west-east incline; and (4) along component dimensions, a steep longitudinal cline, i.e. the farther the west, the lesser the local optimality, and an elevational cline, i.e. the higher the elevation, the lesser the local optimality.Based on the ecological and life-history characteristics of the species and the climate in interior British Columbia, we propose that a selection gradient coupled with directional gene flow was the process influencing the formation of the observed geographic pattern. The selection gradient parallels the general climate pattern from continental northeast to sub-continental southwest. The Gene flow brought the migration of undesirable genes from the coastal subspecies contorta to interior populations of the subspecies latifolia, which further diminished the effectiveness of natural selection. Practical applications through seed transfer in reforestation and genetic resources management are discussed. (C) 2004 Elsevier B.V. All rights reserved.

Keywords

adaptation; local optimality; natural selection; gene flow; lodgepole pine

Published in

Forest Ecology and Management
2004, Volume: 194, number: 1-3, pages: 177-198

UKÄ Subject classification

Forest Science


Publication identifier

DOI: https://doi.org/10.1016/S0378-1127(04)00138-0

Permanent link to this page (URI)

https://res.slu.se/id/publ/118827