Genetic variation between and within populations of Engelmann spruce and subalpine fir

The genetic structure of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) in two adjacent sites in the Colorado Front Range was examined using allozyme data from 21 loci in spruce and 18 loci in fir. The genetic diversity measures of alleles per locus, percent loci polymorphic, and mean heterozygosity did not differ significantly between or within species. However, the observed heterozygosity (0.126 spruce, 0.081 fir) values suggest that Engelmann spruce is more genetically variable than subalpine fir. Mean inbreeding coefficients were twice as high in fir as in spruce (FIS = 0.154 spruce, 0.341 fir). There were significant differences in allele frequencies in both species between and within sites, and among age-classes, with spatial differences greater than temporal differences. F-statistics showed greater genetic differentiation within (FST = 2.3–2.6% spruce, 2.0–2.8% fir) than between sites (FST = 1.7% spruce, 1.3% fir). Both species had higher FST and genetic distance values, yet lower FIS values, for spatial subdivisions within rather than between sites. This pattern suggests that the size of a spatial subdivision, where maximum gene flow is 54 m, approximates the size of the largest panmictic unit. In contrast with studies on other conifers, these results suggest that factors such as differential selection pressures, seed dispersal patterns, and clumped spatial distribution have resulted in genetic differentiation at the microhabitat level in Engelmann spruce and subalpine fir.Key words: genetic variation, genetic structure, allozymes, Engelmann spruce, subalpine fir, microgeographic differentiation.

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Segregation of allozyme loci in megagametophytes of Engelmann spruce and subalpine fir

Genome ◽

10.1139/g88-018 ◽

1988 ◽

Vol 30 (2) ◽

pp. 103-107 ◽

Cited By ~ 1

Author(s):

Kathleen L. Shea

Keyword(s):

Natural Populations ◽

Segregation Ratio ◽

Colorado Front Range ◽

Abies Lasiocarpa ◽

Front Range ◽

Subalpine Fir ◽

Polymorphic Loci ◽

Engelmann Spruce ◽

Low Levels ◽

Allozyme Loci

Segregation ratios and linkage of 10 allozyme loci were examined in haploid megagametophytes obtained from natural populations of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) in the Colorado Front Range. For data pooled over trees, the 1:1 segregation ratio expected at Mendelian loci was obtained for five polymorphic loci in 32 Engelmann spruce trees and for seven polymorphic loci in 40 subalpine fir trees. The Gdh and Idh loci in spruce were very tightly linked: no recombinants were detected among 60 megagametophytes of trees heterozygous for both loci. In fir only the Aco and Pgm-1 loci were linked, with an estimated recombination rate of 0.317 ± 0.073. The low levels of among-tree heterogeneity and of segregation distortion found in these populations suggest that reliable estimates of both genetic variation and outcrossing rates can be obtained using allozyme data from these wind-pollinated species.Key words: segregation, linkage, allozymes, Engelmann spruce, subalpine fir.

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Natural and Advance Regeneration of Engelmann Spruce and Subalpine Fir Compared 21 Years After Site Treatment

The Forestry Chronicle ◽

10.5558/tfc56055-2 ◽

1980 ◽

Vol 56 (2) ◽

pp. 55-57 ◽

Cited By ~ 4

Author(s):

L. J. Herring ◽

R. G. McMinn

Keyword(s):

Natural Regeneration ◽

Mineral Soil ◽

Poor Performance ◽

Abies Lasiocarpa ◽

Subalpine Fir ◽

Engelmann Spruce ◽

Advance Regeneration ◽

Residual Tree ◽

Mean Current ◽

Picea Engelmanni

The mean height of Engelmann spruce (Picea engelmanni Parry) advance growth 21 years after release by overstorey harvesting and residual tree felling, was eight times that of natural regeneration established following brush blade scarification. Subalpine fir (Abies lasiocarpa (Hook.) Nutt.) advance growth was nine times taller than natural regeneration established on scarified soil. Mean current annual height increment of Engelmann spruce and subalpine fir advance growth was 39 and 34 cm, respectively, compared with only 7 cm for natural regeneration on scarified soil. The performance gap does not appear to be narrowing. The poor performance of natural regeneration on mineral soil exposed by blade scarification is attributed to removal of organic and top mineral soil horizons beyond the immediate reach of seedlings. These soil layers remained available to the advance growth. Consideration should be given to preserving advance growth when scarification may be inappropriate.

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Effects of habitat fragmentation on population genetic structure in the white-footed mouse (Peromyscus leucopus)

Canadian Journal of Zoology ◽

10.1139/z00-201 ◽

2001 ◽

Vol 79 (2) ◽

pp. 285-295 ◽

Cited By ~ 33

Author(s):

Catherine A Mossman ◽

Peter M Waser

Keyword(s):

Genetic Variation ◽

Genetic Structure ◽

Habitat Fragmentation ◽

Genetic Differentiation ◽

Population Genetic Structure ◽

Population Genetic ◽

Peromyscus Leucopus ◽

Marginal Effect ◽

Geographic Scale ◽

White Footed Mouse

Habitat fragmentation may have significant consequences for population genetic structure because geographic distance and physical barriers may impede gene flow. In this study, we investigated whether habitat fragmentation affects fine-scale genetic structure of populations of the white-footed mouse (Peromyscus leucopus). We studied 27 populations of P. leucopus, 17 in continuous forest and 10 in isolated woodlots. Populations were trapped in pairs that were either 500 or 2000 m apart. We estimated genetic variation at eight P. leucopus specific microsatellite DNA loci. We discovered significant genetic variation within all populations, but no significant differences in numbers of alleles or heterozygosity between populations. For given population pairs, we found significant genetic differentiation even at very short distances, based on multilocus FST estimates. The amount of genetic differentiation between population pairs was similar in the two habitats. Distance had a marginal effect on genetic differentiation when comparing paired populations separated by 2000 m with those separated by 500 m. However, at a larger geographic scale, there was no evidence of isolation by distance. This study confirms that microsatellite-based studies have the potential to detect interpopulation differentiation at an extremely local scale, and suggests that habitat fragmentation has surprisingly few effects on P. leucopus genetic structure.

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Blowdown and stand development in a Colorado subalpine forest

Canadian Journal of Forest Research ◽

10.1139/x89-186 ◽

1989 ◽

Vol 19 (10) ◽

pp. 1218-1225 ◽

Cited By ~ 58

Author(s):

Thomas T. Veblen ◽

Keith S. Hadley ◽

Marion S. Reid ◽

Alan J. Rebertus

Keyword(s):

18Th Century ◽

Lodgepole Pine ◽

Growth Patterns ◽

Colorado Front Range ◽

Subalpine Forest ◽

Stand Development ◽

Front Range ◽

Southern Rocky Mountains ◽

Engelmann Spruce ◽

Shade Tolerant Species

Stand development of a subalpine forest in the Colorado Front Range following a ca. 15-ha blowdown was examined by analyzing tree population age structures and radial growth patterns. The stand studied was initiated by a fire at the start of the 18th century and was dominated by a dense population of lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) at the time of blowdown in 1973. Before the blowdown, the subcanopy was characterized by abundant subalpine fir (Abieslasiocarpa (Hook.) Nutt.) and scarce Engelmann spruce (Piceaengelmannii (Parry) Engelm.). Comparison with an adjacent control stand, affected only slightly by the blowdown, indicates that new seedling establishment following the blowdown was slight. Instead, the response was dominated by the release of the subcanopy fir and spruce, resulting in acceleration of the successional replacement of lodgepole pine by these shade-tolerant species. Given the >300 years required for an old-growth fir and spruce stand to develop following catastrophic fire, the likelihood of a major canopy disturbance in the form of blowdown and (or) lethal insect attack is high and should be explicitly incorporated into general explanations of stand development of subalpine forests in the southern Rocky Mountains.

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Inonotus tomentosus and the dynamics of unmanaged and partial-cut wet sub-boreal spruce–fir forests

Canadian Journal of Forest Research ◽

10.1139/x07-117 ◽

2007 ◽

Vol 37 (12) ◽

pp. 2663-2676 ◽

Cited By ~ 6

Author(s):

J. E. (Ted) Newbery ◽

Kathy J. Lewis ◽

Michael B. Walters

Keyword(s):

Picea Glauca ◽

Dead Wood ◽

Basal Area ◽

Tree Density ◽

Small Scale ◽

Abies Lasiocarpa ◽

Partial Cutting ◽

Subalpine Fir ◽

Engelmann Spruce ◽

Live Tree

For wet sub-boreal spruce–fir forests (white spruce ( Picea glauca (Moench) Voss) × Engelmann spruce ( Picea engelmannii Parry ex Engelm.) – subalpine fir ( Abies lasiocarpa (Hook.) Nutt.)) in east-central British Columbia, we asked (i) do compositional and structural dynamics differ for unmanaged (UN) and partial-cut (PC) (50% removal 45 years before measurement) forests and (ii) how does Inonotus tomentosus Fr. (Teng) affect these dynamics? Inonotus tomentosus infected stands had 17% less spruce basal area (P = 0.059) than uninfected stands, but PC did not exacerbate I. tomentosus effects. PC and UN had similar live tree density, but UN had lower dead tree density. In all stands, snag longevity was typically <32 years, and ~40 years was required for dead wood to reach decay stage 3 or greater. UN was characterized by variable severity disturbances averaging ~8% of the canopy per decade. Management implications include the following: (i) harvest systems designed to emulate small-scale disturbance could remove trees at 8% of the canopy per decade, varied spatiotemporally, (ii) emulating dead wood abundance with partial cutting may be difficult given the impacts of partial cutting on dead wood abundance, and (iii) forests with moderate levels of I. tomentosus should not respond differently to harvesting than uninfected forests and thus require no special management.

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A comparison of the foliar nutrient status of elfinwood and symmetrically formed tall trees, Colorado Front Range, U.S.A.

Canadian Journal of Botany ◽

10.1139/b96-176 ◽

1996 ◽

Vol 74 (9) ◽

pp. 1461-1475 ◽

Cited By ~ 11

Author(s):

Kenneth A. Barrick ◽

Anna W. Schoettle

Keyword(s):

Nutrient Status ◽

Colorado Front Range ◽

Picea Engelmannii ◽

Nutrient Concentrations ◽

Abies Lasiocarpa ◽

Front Range ◽

Pinus Flexilis ◽

Foliar Nutrient ◽

Foliar Nutrient Concentrations ◽

Pinus Aristata

We tested the hypothesis of nutrient limitation in the trees of the alpine forest – tundra ecotone by comparing the foliar nutrient status of windsculpted elfinwood (also called krummholz) growing at the upper limit of tree success with symmetrically formed toll trees growing at the nearby timberline. The species investigated included Picea engelmannii (Parry) Engelmann, Abies lasiocarpa (Hooker) Nuttall, pinus flexilis james, and Pinus aristata Bailey. The foliar nutrient concentrations of the ecotone trees were similar to other healthy montane forests. Most of the significant differences in mean foliar nutrient concentrations between elfinwood and tall trees indicate lower concentrations in elfinwood trees. We found significantly lower mean phosphorus concentrations in Picea engelmannii and Abies lasiocarpa elfinwood compared with tall trees, but the mean nitrogen–phosphorus ratios were within the normal range. The foliar nutrient status of Pinus aristata elfinwood was similar to tall trees, while Pinus flexilis had considerably more significant differences in nutrient concentrations between the tree forms. Although there are many theoretical processes that could cause nutrient deficiencies at treeline, this study suggests that the elfinwood along the Colorado Front Range is not currently nutrient deficient. We discuss the potential differences in nutrient ecology between elfinwood and tall trees. Keywords: foliar nutrients, alpine ecotone, treeline, elfinwood, krummholz, conifer.

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Assessment of local genetic structure and connectivity of the common eelgrass Zostera marina for seagrass restoration in northern Europe

Marine Ecology Progress Series ◽

10.3354/meps13658 ◽

2021 ◽

Vol 664 ◽

pp. 103-116

Author(s):

L Martínez-García ◽

B Hansson ◽

J Hollander

Keyword(s):

Climate Change ◽

Genetic Variation ◽

Genetic Structure ◽

Genetic Differentiation ◽

Baltic Sea ◽

Zostera Marina ◽

Anthropogenic Impacts ◽

Ecosystem Functions ◽

Long Distance ◽

Seagrass Meadows

Seagrass meadows are one of the most important habitats in coastal regions since they constitute a multifunctional ecosystem providing high productivity and biodiversity. They play a key role in carbon sequestration capacity, mitigation against coastal erosion and as nursery grounds for many marine fish and invertebrates. However, despite these ecosystem functions and services, seagrass meadows are a threatened ecosystem worldwide. In the Baltic Sea, seagrass meadows have declined rapidly, mainly because of eutrophication, anthropogenic activities and climate change. This decline has the potential to erode the genetic variation and genetic structure of the species. In this study, we assessed how genetic variation and genetic differentiation vary among Zostera marina meadows and with a number of environmental characteristics in the county of Scania in southern Sweden. A total of 205 individuals sampled at 12 locations were analysed with 10 polymorphic microsatellite loci. Results showed that in spite of anthropogenic impacts and climate change pressures, locations of Z. marina possessed high genetic variation and weak genetic differentiation, with 3 major genetic clusters. Long-distance dispersal and/or stepping-stone dispersal was found among locations, with higher migration rates within the west coast. Organic matter, salinity and maximum depth appeared to be factors most strongly associated with the genetic structure and morphological variation of Z. marina. These findings contribute significantly in the identification of potential donor sites and the viability of impacted areas to recover from natural recruitment, for the development of effective transplantation measures of Z. marina in the southern Baltic Sea and temperate regions elsewhere.

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Spatial and temporal genetic structure of the New Zealand scallop Pecten novaezelandiae: A multidisciplinary perspective

10.26686/wgtn.17009846.v1 ◽

2021 ◽

Author(s):

◽

Catarina Nunes Soares Silva

Keyword(s):

Population Structure ◽

Genetic Variation ◽

New Zealand ◽

Genetic Structure ◽

Genetic Differentiation ◽

Marine Species ◽

Effective Management ◽

Spatial And Temporal Scales ◽

Marine Connectivity ◽

Management And Conservation

<p>Knowledge about the population genetic structure of species and the factors shaping such patterns is crucial for effective management and conservation. The complexity of New Zealand’s marine environment presents a challenge for management and the classification of its marine biogeographic areas. As such, it is an interesting system to investigate marine connectivity dynamics and the evolutionary processes shaping the population structure of marine species. An accurate description of spatial and temporal patterns of dispersal and population structure requires the use of tools capable of incorporating the variability of the mechanisms involved. However, these techniques are yet to be broadly applied to New Zealand marine organisms. This study used genetic markers to assess the genetic variation of the endemic New Zealand scallop, Pecten novaezelandiae, at different spatial and temporal scales. A multidisciplinary approach was used integrating genetic with environmental data (seascape genetics) and hydrodynamic modelling tools. P. novaezelandiae supports important commercial, recreational and customary fisheries but there is no previous information about its genetic structure. Therefore, twelve microsatellite markers were developed for this study (Chapter 2). Samples (n=952) were collected from 15 locations to determine the genetic structure across the distribution range of P. novaezelandiae. The low genetic structure detected in this study is expected given the recent evolutionary history, the large reproductive potential and the pelagic larval duration of the species (approximately 3 weeks). A significant isolation by distance signal and a degree of differentiation from north to south was apparent, but this structure conflicted with some evidence of panmixia. A latitudinal genetic diversity gradient was observed that might reflect the colonisation and extinction events and insufficient time to reach migration-drift equilibrium during a recent range expansion (Chapter 3). A seascape genetic approach was used to test for associations between patterns of genetic variation in P. novaezelandiae and environmental variables (three geospatial and six environmental variables). Although the geographic distance between populations was an important variable explaining the genetic variation among populations, it appears that levels of genetic differentiation are not a simple function of distance. Evidence suggests that some environmental factors such as freshwater discharge and suspended particulate matter can be contributing to the patterns of genetic differentiation of P. novaezelandiae in New Zealand (Chapter 4). Dispersal of P. novaezelandiae was investigated at a small spatial and temporal scale in the Coromandel fishery using genetic markers integrated with hydrodynamic modelling. For the spatial analysis, samples (n=402) were collected in 2012 from 5 locations and for the temporal analysis samples (n=383) were collected in 2012 and 2014 from 3 locations. Results showed small but significant spatial and temporal genetic differentiation, suggesting that the Coromandel fishery does not form a single panmictic unit with free gene flow and supporting a model of source-sink population dynamics (Chapter 5). The importance of using multidisciplinary approaches at different spatial and temporal scales is widely recognized as a means to better understand the complex processes affecting marine connectivity. The outcomes of this study highlight the importance of incorporating these different approaches, provide vital information to assist in effective management and conservation of P. novaezelandiae and contribute to our understanding of evolutionary processes shaping population structure of marine species.</p>

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