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50 results for “marginal populations”
Data from: A test of the central-marginal hypothesis using population genetics and ecological niche modelling in an endemic salamander (Ambystoma barbouri)
The central-marginal hypothesis (CMH) predicts that population size, genetic diversity, and genetic connectivity are highest at the core and decrease near the edges of species' geographic distributions. We provide a test of the CMH using three replicated core-to-edge transects that encompass nearly the entire geographic range of the endemic streamside salamander (Ambystoma barbouri). We confirmed that the mapped core of the distribution was the most suitable habitat using ecological niche modelling (ENM) and via genetic estimates of effective population sizes. As predicted by the CMH, we found statistical support for decreased genetic diversity, effective population size, and genetic connectivity from core to edge in western and northern transects, yet not along a southern transect. Based on our niche model, habitat suitability is lower towards the southern range edge, presumably leading to conflicting core-to-edge genetic patterns. These results suggest that multiple processes may influence a species' distribution based on the heterogeneity of habitat across a species' range and that replicated sampling may be needed to accurately test the CMH. Our work also emphasizes the importance of identifying the geographic range core with methods other than using the Euclidean center on a map, which may help to explain discrepancies among other empirical tests of the CMH. Assessing core to edge population genetic patterns across an entire species' range accompanied with ENM can inform our general understanding of the mechanisms leading to species' geographic range limits.
Data from: Partial support for the central–marginal hypothesis within a population: reduced genetic diversity but not increased differentiation at the range edge of an island endemic bird
Large-scale population comparisons have contributed to our understanding of the evolution of geographic range limits and species boundaries, as well as the conservation value of populations at range margins. The central–marginal hypothesis (CMH) predicts a decline in genetic diversity and an increase in genetic differentiation toward the periphery of species' ranges due to spatial variation in genetic drift and gene flow. Empirical studies on a diverse array of taxa have demonstrated support for the CMH. However, nearly all such studies come from widely distributed species, and have not considered if the same processes can be scaled down to single populations. Here, we test the CMH on a species composed of a single population: the Island Scrub-Jay (Aphelocoma insularis), endemic to a 250 km2 island. We examined microsatellite data from a quarter of the total population and found that homozygosity increased toward the island's periphery. However, peripheral portions of the island did not exhibit higher genetic differentiation. Simulations revealed that highly localized dispersal and small total population size, but not spatial variation in population density, were critical for generating fine-scale variation in homozygosity. Collectively, these results demonstrate that microevolutionary processes driving spatial variation in genetic diversity among populations can also be important for generating spatial variation in genetic diversity within populations.
FIGURE 5 in Penelope superciliaris pseudonyma Neumann, 1933 (Aves, Cracidae) is the valid name for the blue-faced population of Rusty-margined Guan endemic to the Madeira-Tapajós interfluvium of central Amazonian Brazil
FIGURE 5. Type localities of subspecies proposed by Neumann (1933; red circle) and Nardelli (1993; white circle), and specimens collected by MZUSP expeditions in the central Amazonian area of Brazil (green circles), with the distribution of Penelope superciliaris shaded green; the inset map of South America shows the study region (shaded rectangle) and the wider distribution of Penelope superciliaris (shaded green) according to BirdLife International and NatureServe (2015).
FIGURE 1. Lectotype FMNH 407458 in Penelope superciliaris pseudonyma Neumann, 1933 (Aves, Cracidae) is the valid name for the blue-faced population of Rusty-margined Guan endemic to the Madeira-Tapajós interfluvium of central Amazonian Brazil
FIGURE 1. Lectotype FMNH 407458 of Penelope superciliaris pseudonyma Neumann, 1933, deposited at the Field Museum of Natural History. Photos: Thiago V. V. Costa
FIGURE 4 in Penelope superciliaris pseudonyma Neumann, 1933 (Aves, Cracidae) is the valid name for the blue-faced population of Rusty-margined Guan endemic to the Madeira-Tapajós interfluvium of central Amazonian Brazil
FIGURE 4. Blue face skin of recently collected specimens: MZUSP 95764 seconds (A) and MZUSP 86399 minutes (B) after being collected, showing the rapid loss of color in bare parts. Photos: Fabio Schunck
FIGURE 3 in Penelope superciliaris pseudonyma Neumann, 1933 (Aves, Cracidae) is the valid name for the blue-faced population of Rusty-margined Guan endemic to the Madeira-Tapajós interfluvium of central Amazonian Brazil
FIGURE 3. Dorsal (A) and ventral view (B) of the seven specimens collected in the Madeira-Tapajós interfluvium. Left to right: LSUMZ B-86475, MZUSP 97239, MZUSP 95762, LSUMZ B-80658, MZUSP 95764, MZUSP 86399 and MZUSP 86400. Photos: Fabio Schunck
FIGURE 2 in Penelope superciliaris pseudonyma Neumann, 1933 (Aves, Cracidae) is the valid name for the blue-faced population of Rusty-margined Guan endemic to the Madeira-Tapajós interfluvium of central Amazonian Brazil
FIGURE 2. Labels attached to the lectotype FMNH 407458 of Penelope superciliaris pseudonyma Neumann, 1933, collected by H. Lako. Newest label (A, B) translated from German from the oldest label (C). Photos: Thiago V. V. Costa
Subspecies and Distribution. T.n.napuF.Cuvier,1822—SMyanmar,Thai/MalayPeninsula,islandsoffWMalayPeninsula(Langkawi&Pangkor),Borneo,SSumatra,BangkaI,islandsoffBorneo(Laut&Serasan). T.n.bangue:Chasen&Kloss,1931—BanggiIandBalembanganI,offNBorneo. T.n.bunguranensisMiller,1901—NatunaIs(=Bunguran),oftWBorneo. T.n.neubronneriSody,1931—NSumatra. T.n.nmiasisLyon,1916—NiasI,offWSumatra. T.n.rufulusMiller,1900—TiomanI,offEMalayPeninsula,RiauandLinggaArchipelagos. T. n. terutus Thomas & Wroughton, 1909 — Terutau I, off W Malay Peninsula. The species was recently reconfirmed for Singapore. Maps that include Vietnam, Cambodia, and Laos in the distribution range are based on the earlier assumption that 7. versicolor was a subspecies of 1. napu. Subsequent studies have indicated that 7. versicolor is a distinct species, and that the range of 1. napu therefore does not extend into Cambodia, Laos, and Vietnam. The northern limit on the Thai-Malay peninsula is not well defined. Specimens of 1. napu have been collected from as far north as Bankachon in southern Myanmar (10° 08" N), but despite fairly intensive camera-trapping in Kui Buri National Park, Thailand (12° N), 7. napu has not been photographed there. At the northern margin ofits range, it is generally rare. It has been reported, for example, that during the flooding of the Chiew Larn Reservoir (Surat Thani Province; about 9° N, 98° 45' E), only six 7. napu were rescued compared with 172 71. kanchil. This area is the transition zone from wetter evergreen forest to drier deciduous types, and it might be that 7° napu is not well adapted to the drier forest types towards the northern limit ofits range. There are unconfirmed reports of the species on Java, where it may have been confused with one of the two color morphs of 7. javanicus. As explained in the Taxonomy section, the subspecific status of the populations of several islands remains unclear. in Tragulidae
Subspecies and Distribution. T.n.napuF.Cuvier,1822—SMyanmar,Thai/MalayPeninsula,islandsoffWMalayPeninsula(Langkawi&Pangkor),Borneo,SSumatra,BangkaI,islandsoffBorneo(Laut&Serasan). T.n.bangue:Chasen&Kloss,1931—BanggiIandBalembanganI,offNBorneo. T.n.bunguranensisMiller,1901—NatunaIs(=Bunguran),oftWBorneo. T.n.neubronneriSody,1931—NSumatra. T.n.nmiasisLyon,1916—NiasI,offWSumatra. T.n.rufulusMiller,1900—TiomanI,offEMalayPeninsula,RiauandLinggaArchipelagos. T. n. terutus Thomas & Wroughton, 1909 — Terutau I, off W Malay Peninsula. The species was recently reconfirmed for Singapore. Maps that include Vietnam, Cambodia, and Laos in the distribution range are based on the earlier assumption that 7. versicolor was a subspecies of 1. napu. Subsequent studies have indicated that 7. versicolor is a distinct species, and that the range of 1. napu therefore does not extend into Cambodia, Laos, and Vietnam. The northern limit on the Thai-Malay peninsula is not well defined. Specimens of 1. napu have been collected from as far north as Bankachon in southern Myanmar (10° 08" N), but despite fairly intensive camera-trapping in Kui Buri National Park, Thailand (12° N), 7. napu has not been photographed there. At the northern margin ofits range, it is generally rare. It has been reported, for example, that during the flooding of the Chiew Larn Reservoir (Surat Thani Province; about 9° N, 98° 45' E), only six 7. napu were rescued compared with 172 71. kanchil. This area is the transition zone from wetter evergreen forest to drier deciduous types, and it might be that 7° napu is not well adapted to the drier forest types towards the northern limit ofits range. There are unconfirmed reports of the species on Java, where it may have been confused with one of the two color morphs of 7. javanicus. As explained in the Taxonomy section, the subspecific status of the populations of several islands remains unclear.
Data from: Genome-wide assessment of kokanee salmon stock diversity, population history and hatchery representation at the northern range margin
<p>Freshwater fisheries represent important natural resources, yet a vast majority are threatened by anthropogenic stressors. Accurate baseline information on stock diversity, population history and hatchery representation are required for implementing effective conservation and management strategies for mitigating declines. Genetic tools have played key roles for informing fisheries management, including for kokanee, the freshwater resident form of sockeye salmon (<i>Oncorhynchus nerka</i>), particularly in the southern portion of its North American range. Here, we investigated stock diversity, population history and hatchery representation of kokanee at the northern extent of its range in Canada in Kluane National Park and Reserve (KNPR) in the Yukon that underwent a 12-year population crash followed by a rapid increase in numbers. Using restriction-site associated DNA sequencing, we genotyped individuals at 11,442 single nucleotide polymorphisms (SNPs) that were sampled from putative reproductive ecotypes spawning on the shore of Sockeye Lake (n=26), within Sockeye Creek (n=20) or near an outlet in between (n=2), as well as broodstock from the Whitehorse Rapids Hatchery (n=29). We found no evidence of wild stock diversity or ecotype differentiation based on neutral SNPs nor outlier loci. Within-population genetic diversity and effective population size were substantially higher in the wild population relative to the hatchery and significant differentiation was detected, suggesting the hatchery population was not representative of wild stock diversity. Overall, our results suggest that separate management of kokanee in KNPR based on ecotype is not warranted at this time and that supplementation with the existing hatchery stock is not appropriate.</p>
Distribution. Fairly widespread in Zimbabwe, extending marginally into S Zambia, E Malawi, and W Mozambique, with isolated populations occurring in Eritrea, Ethiopia, South Sudan, E Uganda, W & SE Kenya, NE Tanzania, and N Zambia. in Molossidae
Distribution. Fairly widespread in Zimbabwe, extending marginally into S Zambia, E Malawi, and W Mozambique, with isolated populations occurring in Eritrea, Ethiopia, South Sudan, E Uganda, W & SE Kenya, NE Tanzania, and N Zambia.
Subspecies and Distribution. P. l. longimembris Coues, 1875 — SW USA (Mojave Desert and Transverse Ranges, SW California). P. l. aestivus Huey, 1928 — NW Mexico (W base Sierra Juarez to Valle de la Trinidad, N Baja California). P.l. arizonensis Goldman, 1931 — SW USA (SC Utah and NC Arizona to SE Nevada). P. l.bangsi Mearns, 1898 — SW USA (W Colorado Desert of S California). P. l. bombycinus Osgood, 1907 — SW USA and NW Mexico (lower Colorado River Valley of SE California, SW Arizona, NE Baja California, and NW Sonora). P. l. brevinasus Osgood, 1900 — SW USA (arid coastal basins of SW California). P. l. gulosus Hall, 1941 — W USA (along the W margin of former Pleistocene Lake Bonneville in the Great Basin of E Nevada and W Utah). P. l. internationalis Huey, 1939 — SW USA and NW Mexico (SC California and adjacent NC Baja California). P. l. kinoensis Huey, 1935 — NW Mexico (disjunct and geographically restricted population along Bahia Kino, W Sonora), but may be extinct. P. l. nevadensis Merriam, 1894 — W USA (Great Basin of SE Oregon, NE California, and NC Nevada). P. l. pacificus Mearns, 1898 — SW USA (coastal plains of SW California to the USA-Mexico border). P. I. panamintinus Merriam, 1894 — SW USA (Great Basin of W Nevada and SE California). P. l. pimensis Huey, 1937 — SW USA (disjunct distribution in SC Arizona). P. l. salinensis Bole, 1937 — SW USA (restricted distribution in the Salinas Valley of SE California). P. l. tularensis Richardson, 1937 — SW USA (restricted distribution in the upper valley of the Kern River, SC California). P. l. venustus Huey, 1930 — NW Mexico (known only from the type locality of San Agustin, NC Baja California). in Heteromyidae
Subspecies and Distribution. P. l. longimembris Coues, 1875 — SW USA (Mojave Desert and Transverse Ranges, SW California). P. l. aestivus Huey, 1928 — NW Mexico (W base Sierra Juarez to Valle de la Trinidad, N Baja California). P.l. arizonensis Goldman, 1931 — SW USA (SC Utah and NC Arizona to SE Nevada). P. l.bangsi Mearns, 1898 — SW USA (W Colorado Desert of S California). P. l. bombycinus Osgood, 1907 — SW USA and NW Mexico (lower Colorado River Valley of SE California, SW Arizona, NE Baja California, and NW Sonora). P. l. brevinasus Osgood, 1900 — SW USA (arid coastal basins of SW California). P. l. gulosus Hall, 1941 — W USA (along the W margin of former Pleistocene Lake Bonneville in the Great Basin of E Nevada and W Utah). P. l. internationalis Huey, 1939 — SW USA and NW Mexico (SC California and adjacent NC Baja California). P. l. kinoensis Huey, 1935 — NW Mexico (disjunct and geographically restricted population along Bahia Kino, W Sonora), but may be extinct. P. l. nevadensis Merriam, 1894 — W USA (Great Basin of SE Oregon, NE California, and NC Nevada). P. l. pacificus Mearns, 1898 — SW USA (coastal plains of SW California to the USA-Mexico border). P. I. panamintinus Merriam, 1894 — SW USA (Great Basin of W Nevada and SE California). P. l. pimensis Huey, 1937 — SW USA (disjunct distribution in SC Arizona). P. l. salinensis Bole, 1937 — SW USA (restricted distribution in the Salinas Valley of SE California). P. l. tularensis Richardson, 1937 — SW USA (restricted distribution in the upper valley of the Kern River, SC California). P. l. venustus Huey, 1930 — NW Mexico (known only from the type locality of San Agustin, NC Baja California).
Strong genetic structure and divergence of marginal populations of black poplar in Poland
<p><strong>The dataset comprises nuclear microsatellite data (PCR products lengths) used in the paper "Strong genetic structure and divergence of marginal populations of black poplar in Poland".</strong></p> <p>Abstract: Genetic diversity is crucial to secure the survival and sustainability of ecosystems. Given anthropogenic pressure, as well as the projected alterations connected with the level and circulation of water, riparian forests are of particular concern. In this paper, we assessed the genetic variation of black poplar – one of the keystone tree species of riverine forests. The natural habitats of black poplar have been severely transformed leading to a significant decline of its population size. Using a set of 18 nuclear microsatellites and geographic location data, we studied 26 remnant populations (1,261 trees) located along the biggest river valleys in Poland. Our main goal was to assess the overall genetic variation and to verify if range fragmentation and habitat transformation have disrupted gene exchange among populations. Genotyping revealed that 261 trees were clones. The level of clonality was generally higher in the two most transformed river valleys (the Oder and Warta). All populations have probably gone through a drastic genetic bottleneck in the distant past, and most of them have low effective population sizes. Still, the overall level of genetic variation remains high, but certain populations require attention due to their lower genetic variation, higher clonality and strong spatial genetic structure. Genetic differentiation was low, yet Bayesian clustering supported the existence of 11 separate gene pools. According to the results, the intensity of gene exchange is very low and limited to adjacent stands. Relatively free gene flow occurs only along the Vistula, particularly in its middle section which is characterized by the highest genetic variation. The greatest genetic structuring was observed along the Oder. Populations located at the range margin had unique gene pools and showed signs of genetic divergence and reduction of variation caused by genetic drift. We conclude that human activities have seriously impacted the gene pool of black poplar in Poland by disrupting landscape connectivity and preventing the species from generative reproduction. The study provides practical guidelines on how to develop and implement the conservation program for the gene pool of black poplar in Poland.</p>
Mixed Methods Study Protocol_Chronic Pain and Marginalized Populations
ClinicalTrials.gov study NCT03945877. IPD Sharing: NO. Countries: 1. Publications: 13.
myoActivation® for Chronic Pain in a Marginalized Population
ClinicalTrials.gov study NCT04261959. IPD Sharing: NO. Countries: 1. Publications: 1.
Data from: Mycorrhizal interactions do not influence plant-herbivore interactions in populations of Clarkia xantiana ssp. xantiana spanning from center to margin of the geographic range
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Data from: Partial support for the central–marginal hypothesis within a population: reduced genetic diversity but not increased differentiation at the range edge of an island endemic bird
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Data from: Genetic divergence and signatures of natural selection in marginal populations of a keystone, long-lived conifer, eastern white pine (Pinus strobus) from northern Ontario
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Data from: Range-wide distribution of genetic diversity in the North American tree Juglans cinerea: a product of range shifts, not ecological marginality or recent population decline
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Data from: A test of the central-marginal hypothesis using population genetics and ecological niche modelling in an endemic salamander (Ambystoma barbouri)
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Data from: Chloroplast population genetics reveals low levels of genetic variation and conformation to the central–marginal hypothesis in Taxus wallichiana var. mairei, an endangered conifer endemic to China
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Allen Brain Atlas
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