Landscape-Level and Fine-Scale Genetic Structure of the Neotropical TreeProtium spruceanum(Burseraceae)

Knowledge of genetic structure at different scales and correlation with the current landscape is fundamental for evaluating the importance of evolutionary processes and identifying conservation units. Here, we used allozyme loci to examine the spatial genetic structure (SGS) of 230 individuals ofProtium spruceanum, a native canopy-emergent in five fragments of Brazilian Atlantic forest (1 to 11.8 ha), and four ecological corridors (460 to 1 000 m length). Wright's statistic and Mantel tests revealed little evidence of significant genetic structure at the landscape-scale (; , ). At fine-scale SGS, low levels of relatedness within fragments and corridors (, ) were observed. Differences in the levels and distribution of the SGS at both spatial scales are discussed in relation to biological and conservation strategies of corridors and forest fragments.

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Spatial genetic structure in the very rare and species-rich Picea chihuahuana tree community (Mexico)

Silvae Genetica ◽

10.1515/sg-2014-0020 ◽

2014 ◽

Vol 63 (1-6) ◽

pp. 149-158 ◽

Cited By ~ 9

Author(s):

C. Z. Quiñones-Pérez ◽

S. L. Simental-Rodríguez ◽

C. Sáenz-Romero ◽

J. P. Jaramillo-Correa ◽

C. Wehenkel

Keyword(s):

Genetic Structure ◽

Populus Tremuloides ◽

Isolation By Distance ◽

Spatial Genetic Structure ◽

Strong Support ◽

Forest Tree ◽

Conservation Strategies ◽

Fine Scale ◽

Ecological Features ◽

Tree Community

Abstract In natural plant populations, the spatial genetic structure (SGS) is occasionally associated with evolutionary and ecological features such as the mating system, individual fitness, inbreeding depression and natural selection of the species of interest. The very rare Mexican P. chihuahuana tree community covers an area no more than 300 ha and has been the subject of several studies concerning its ecology and population genetics. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. However, analysis of the fine-scale SGS in this special forest tree community has not yet been conducted, which might help enrich the above mentioned conservation programs. In this study, we examined the SGS of this community, mostly formed by P. chihuahuana Martínez, Pinus strobiformis Ehrenberg ex Schlechtendah, Pseudotsuga menziesii (Mirb.) Franco, and Populus tremuloides Michx, in 14 localities at both the fine and large scales, with the aim of obtaining a better understanding of evolutionary processes. We observed a non-significant autocorrelation in fine-scale SGS, suggesting that the genetic variants of all four tree species are randomly distributed in space within each sampled plot of 50 x 50 m. At the larger scale, the autocorrelation was highly significant for P. chihuahuana and P. menziesii, probably as a result of insufficient gene flow due to the extreme population isolation and small sizes. For these two species our results provided strong support for the theory of isolation by distance.

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Gene flow and fine-scale spatial genetic structure in Cabralea canjerana (Meliaceae), a common tree species from the Brazilian Atlantic forest

Journal of Tropical Ecology ◽

10.1017/s0266467416000067 ◽

2016 ◽

Vol 32 (2) ◽

pp. 135-145 ◽

Cited By ~ 7

Author(s):

Arthur Tavares de Oliveira Melo ◽

Edivani Villaron Franceschinelli

Keyword(s):

Gene Flow ◽

Genetic Structure ◽

Atlantic Forest ◽

Tree Species ◽

Spatial Genetic Structure ◽

Molecular Ecology ◽

Spatial Distance ◽

Forest Fragments ◽

Fine Scale ◽

Flow Process

Abstract:The Atlantic forest is the biome most severely affected by deforestation in Brazil. Cabralea canjerana spp. canjerana is a dioecious tree species with widespread distribution in the Neotropical region. This species is considered a model to ascertain population ecology parameters for endangered plant species from the Atlantic forest. Fine-scale spatial genetic structure and pollen-mediated gene flow are crucial information in landscape genetics and evolutionary ecology. A total of 192 adults and 121 offspring were sampled in seven C. canjerana populations in the Southern Minas Gerais State, Brazil, to assess whether pollen-mediated gene flow is able to prevent spatial genetic structure within and among Atlantic forest fragments. Several molecular ecology parameters were estimated using microsatellite loci. High levels of genetic diversity (HE = 0.732) and moderate population structure (θ = 0.133) were recorded. No significant association between kinship and spatial distance amongst individuals within each population (Sp = 0.000109) was detected. Current pollen-mediated gene flow occurs mainly within forest fragments, probably due to short-distance flights of the pollinator of C. canjerana, and also the forest fragmentation may have restricted flight distance. The high levels of genetic differentiation found amongst the seven sites sampled demonstrated how habitat fragmentation affects the gene flow process in natural areas.

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Fine-scale genetic structure in populations of Quercus variabilis (Fagaceae) from southern Korea

Canadian Journal of Botany ◽

10.1139/b02-094 ◽

2002 ◽

Vol 80 (10) ◽

pp. 1034-1041 ◽

Cited By ~ 6

Author(s):

Mi Yoon Chung ◽

Myong Gi Chung

Keyword(s):

Genetic Structure ◽

South Korea ◽

Spatial Autocorrelation ◽

Spatial Genetic Structure ◽

Fine Scale ◽

Genetic Structuring ◽

Quercus Variabilis ◽

Southern Korea ◽

Allozyme Loci ◽

Landscape Level

Quercus variabilis Blume (Fagaceae) is a deciduous broad-leaved tree, and an important forest element among the hillsides of southern Korea. To date, there are contrasting results with respect to fine-scale spatial genetic structure among adults in populations of several oak species; some studies have shown evidence of significant within-population spatial genetic structure, while others found weak or little evidence of fine-scale genetic structuring within populations. We used allozyme loci, Wright's F statistics, and multilocus spatial autocorrelation statistics to examine the distribution of genetic diversity and the spatial genetic structure within three undisturbed populations at a landscape level (72.5 ha, 500 × 1450 m) on Dolsan Island, South Korea. The spatial autocorrelation analyses of adults showed little evidence of fine-scale genetic structuring within populations, which could be due to random mortality among related seedlings, resulting in extensive thinning within maternal half-sib groups. Alternatively, low genetic differentiation between adjacent populations (mean FST = 0.023) and little within-population spatial genetic structure suggest probable secondary acorn movement by animals. Our results are very similar to those observed in three populations of Quercus acutissima at a landscape level (15 ha, 250 × 600 m) on Oenaro Island, South Korea. Together, these studies describe relatively subtle differences in genetic structure among adjacent populations of oaks on southern islands in Korea.Key words: allozymes, Quercus variabilis, Fagaceae, landscape level, multiple populations, spatial genetic structure.

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Genomic variation in the American pika: signatures of geographic isolation and implications for conservation

BMC Ecology and Evolution ◽

10.1186/s12862-020-01739-9 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Kelly B. Klingler ◽

Joshua P. Jahner ◽

Thomas L. Parchman ◽

Chris Ray ◽

Mary M. Peacock

Keyword(s):

Genetic Variation ◽

Genetic Structure ◽

Sierra Nevada ◽

Spatial Genetic Structure ◽

Spatial Scales ◽

Thermal Sensitivity ◽

Genomic Variation ◽

Genome Wide ◽

A Genome ◽

American Pika

Abstract Background Distributional responses by alpine taxa to repeated, glacial-interglacial cycles throughout the last two million years have significantly influenced the spatial genetic structure of populations. These effects have been exacerbated for the American pika (Ochotona princeps), a small alpine lagomorph constrained by thermal sensitivity and a limited dispersal capacity. As a species of conservation concern, long-term lack of gene flow has important consequences for landscape genetic structure and levels of diversity within populations. Here, we use reduced representation sequencing (ddRADseq) to provide a genome-wide perspective on patterns of genetic variation across pika populations representing distinct subspecies. To investigate how landscape and environmental features shape genetic variation, we collected genetic samples from distinct geographic regions as well as across finer spatial scales in two geographically proximate mountain ranges of eastern Nevada. Results Our genome-wide analyses corroborate range-wide, mitochondrial subspecific designations and reveal pronounced fine-scale population structure between the Ruby Mountains and East Humboldt Range of eastern Nevada. Populations in Nevada were characterized by low genetic diversity (π = 0.0006–0.0009; θW = 0.0005–0.0007) relative to populations in California (π = 0.0014–0.0019; θW = 0.0011–0.0017) and the Rocky Mountains (π = 0.0025–0.0027; θW = 0.0021–0.0024), indicating substantial genetic drift in these isolated populations. Tajima’s D was positive for all sites (D = 0.240–0.811), consistent with recent contraction in population sizes range-wide. Conclusions Substantial influences of geography, elevation and climate variables on genetic differentiation were also detected and may interact with the regional effects of anthropogenic climate change to force the loss of unique genetic lineages through continued population extirpations in the Great Basin and Sierra Nevada.

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