Abstract:Recently, a group of public and private organizations responsible for managing much of the timberland in western Oregon and Washington formed the Pacific Northwest forest tree Gene Conservation Group (GCG) to ensure that the evolutionary potential of important regional tree species is maintained. The group is first compiling data to evaluate the genetic resource status of several species of conifers both at their original location (in situ) and at some other location (ex situ). We summarize the ex situ genetic… Show more
“…Spatial genetic substructure and past extinctions and recolonizations have probably reduced the effective population sizes (N e ) in all studied populations to levels considerably lower than those expected in panmictic populations with the same number of trees (Whitlock and Barton 1997). Conservation efforts are often more critical for tree species growing under severe environmental conditions and having small fragmented populations than for species of interest for tree improvement (Yanchuk 2001;Lipow et al 2002). All P. mugo populations in the Rila and Pirin Mountains fall within national parks and are protected from logging by law.…”
Section: Implications For Gene Conservation Of P Mugomentioning
Genetic variation of 17 populations of Pinus mugo Turra was studied using 10 polymorphic allozyme loci. Polymorphism and gene diversity in these populations were comparable to mean values for gymnosperm species, but slightly lower than in pines with large and continuous ranges. We did not find significant interpopulation differentiation (FST = 0.041) or isolation by distance, suggesting that gene flow might be extensive or that the time elapsed since the species range became fragmented has been too short for genetic differentiation to arise via genetic drift. We detected moderate and statistically significant levels of inbreeding (mean FIS = 0.252) for all loci in all populations. Although there are many possible explanations for this nonequilibrium population structure, we propose that the main reasons for its ubiquity are the peculiar growth form and reproductive biology of P. mugo, which promote excessive near-neighbor pollinations. Populations in Vitosha Mountain and western Stara Planina had the highest levels of inbreeding and the lowest observed heterozygosities. All populations in these mountains are small and isolated, but none of them is under a special regime of protection. Thus, the conservation status of P. mugo populations in Vitosha Mountain and western Stara Planina may deserve reevaluation. Future gene conservation efforts should focus on obtaining information on the genetic variation of adaptive traits in P. mugo.
“…Spatial genetic substructure and past extinctions and recolonizations have probably reduced the effective population sizes (N e ) in all studied populations to levels considerably lower than those expected in panmictic populations with the same number of trees (Whitlock and Barton 1997). Conservation efforts are often more critical for tree species growing under severe environmental conditions and having small fragmented populations than for species of interest for tree improvement (Yanchuk 2001;Lipow et al 2002). All P. mugo populations in the Rila and Pirin Mountains fall within national parks and are protected from logging by law.…”
Section: Implications For Gene Conservation Of P Mugomentioning
Genetic variation of 17 populations of Pinus mugo Turra was studied using 10 polymorphic allozyme loci. Polymorphism and gene diversity in these populations were comparable to mean values for gymnosperm species, but slightly lower than in pines with large and continuous ranges. We did not find significant interpopulation differentiation (FST = 0.041) or isolation by distance, suggesting that gene flow might be extensive or that the time elapsed since the species range became fragmented has been too short for genetic differentiation to arise via genetic drift. We detected moderate and statistically significant levels of inbreeding (mean FIS = 0.252) for all loci in all populations. Although there are many possible explanations for this nonequilibrium population structure, we propose that the main reasons for its ubiquity are the peculiar growth form and reproductive biology of P. mugo, which promote excessive near-neighbor pollinations. Populations in Vitosha Mountain and western Stara Planina had the highest levels of inbreeding and the lowest observed heterozygosities. All populations in these mountains are small and isolated, but none of them is under a special regime of protection. Thus, the conservation status of P. mugo populations in Vitosha Mountain and western Stara Planina may deserve reevaluation. Future gene conservation efforts should focus on obtaining information on the genetic variation of adaptive traits in P. mugo.
“…The in situ genetic resources we evaluated are only one component of an overall gene conservation strategy (Yanchuk & Lester 1996; Lipow et al 2001). The tree species also have extensive genetic resources in ex situ collections, including progeny tests, seed orchards, and seed stores (Lipow et al 2001; S.R.L., K.V.‐B., J.B.S., J.A.H., & C.M., unpublished data). In Oregon and Washington, progeny from >1679 noble fir selections from natural populations are maintained in genetic tests or in 1 of 14 seed orchards.…”
We developed a gap analysis approach to evaluate whether the genetic resources conserved in situ in protected areas are adequate for conifers in western Oregon and Washington (U.S.A.). We developed geographic information system layers that detail the location of protected areas and the distribution and abundance of each tree species (noble fir [Abies procera Rehd.] and Douglas-fir [Pseudotsuga menzeisii Mirb.]). Distribution and abundance were inferred from available spatial data showing modeled potential and actual vegetation. We stratified the distribution of each species into units for genetic analysis using seed and breeding zones and ecoregions. Most strata contained at least 5000 reproductive-age individuals in protected areas, indicating that genetic resources were well protected in situ throughout most of the study region. Strict in situ protection was limited, however, for noble fir in the Willapa Hills of southwestern Washington. An in situ genetic resource gap arguably occurred for Douglas-fir in the southern Puget lowlands, but this gap was filled by extensive ex situ genetic resources from the same region. The gap analysis method was an effective tool for evaluating the genetic resources of forest trees across a large region.
Análisis de Claros de Recursos Genéticos Conservados paraÁrboles de BosqueResumen: Desarrollamos un método de análisis de claros para evaluar si los recursos genéticos conservados in situ enáreas protegidas son adecuados para coníferas en el oeste de Oregon y Washington (E. U. A.). Desarrollamos capas de sistema de información geográfica que detallan la localización deáreas protegidas y la distribución y abundancia de cada especie deárbol (Abies procera Rehd. y Pseudotsuga menzeisii Mirb). La distribución y abundancia fueron inferidas a partir de datos espaciales disponibles que muestran la vegetación potencial modelada y la vegetación existente. Estratificamos la distribución de cada especie en unidades para el análisis genético utilizando zonas de semillas y reproducción y ecoregiones. La mayoría de los estratos contenían por los menos 5000 individuos en edad reproductiva enáreas protegidas, lo que indica que los recursos genéticos estaban bien protegidos in situ en casi toda la región de estudio. Sin embargo, la protección in situ estricta estaba limitada para A. procera en las Colinas Willapa del suroeste de Washington. Se podría decir que ocurrió un claro de recursos genéticos in situ para P. menzeisii en las tierras bajas del sur de Puget, pero este claro fue llenado por recursos genéticos extensivos ex situ de la misma región. Encontramos que el método de análisis de claros es una herramienta valiosa para evaluar los recursos genéticos deárboles de bosque en una región amplia. † †Current address:
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