scholarly journals Long-distance dispersal, ice sheet dynamics, and mountaintop isolation underlie the genetic structure of glacier ice worms

2018 ◽  
Author(s):  
Scott Hotaling ◽  
Daniel H. Shain ◽  
Shirley A. Lang ◽  
Robin K. Bagley ◽  
Lusha M. Tronstad ◽  
...  
Keyword(s):  
Sequence Data ◽  
Ice Sheet ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Biogeographic Patterns ◽  
Biogeographic History ◽  
Historical Factors ◽  
Glacier Ice ◽  
Ice Sheet Dynamics ◽  
Migrating Birds

AbstractDisentangling the contemporary and historical factors underlying the spatial distributions of species is a central goal of biogeography. For species with broad distributions but little capacity to actively disperse, disconnected geographic distributions highlight the potential influence of passive, long-distance dispersal (LDD) on their evolutionary histories. However, dispersal alone cannot completely account for the biogeography of any species, and other factors–e.g., habitat suitability, life history–must also be considered. North American ice worms (Mesenchytraeus solifugus) are ice-obligate annelids that inhabit coastal glaciers from Oregon to Alaska. Previous studies identified a complex biogeographic history for ice worms, with evidence for genetic isolation, unexpectedly close relationships among geographically disjunct lineages, and contemporary migration across large (> 1,500 km) areas of unsuitable habitat. In this study, we analyzed genome-scale sequence data for most of the known ice worm range. We found clear support for divergence between populations along the Pacific Coast and the inland flanks of the Coast Mountains (mean FST = 0.60), likely precipitated by episodic ice sheet expansion and contraction during the Pleistocene. We also found support for LDD of ice worms from Alaska to Vancouver Island, perhaps mediated by migrating birds. Our results highlight the power of genomic data for disentangling complex biogeographic patterns, including the presence of LDD.

scholarly journals Long-distance dispersal, ice sheet dynamics and mountaintop isolation underlie the genetic structure of glacier ice worms

2019 ◽  
Vol 286 (1905) ◽  
pp. 20190983 ◽  
Author(s):  
Scott Hotaling ◽  
Daniel H. Shain ◽  
Shirley A. Lang ◽  
Robin K. Bagley ◽  
Lusha M. Tronstad ◽  
...  
Keyword(s):  
Sequence Data ◽  
Ice Sheet ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Biogeographic Patterns ◽  
Biogeographic History ◽  
Historical Factors ◽  
Glacier Ice ◽  
Ice Sheet Dynamics ◽  
Migrating Birds

Disentangling the contemporary and historical factors underlying the spatial distributions of species is a central goal of biogeography. For species with broad distributions but little capacity to actively disperse, disconnected geographical distributions highlight the potential influence of passive, long-distance dispersal (LDD) on their evolutionary histories. However, dispersal alone cannot completely account for the biogeography of any species, and other factors—e.g. habitat suitability, life history—must also be considered. North American ice worms ( Mesenchytraeus solifugus ) are ice-obligate annelids that inhabit coastal glaciers from Oregon to Alaska. Previous studies identified a complex biogeographic history for ice worms, with evidence for genetic isolation, unexpectedly close relationships among geographically disjunct lineages, and contemporary migration across large (e.g. greater than 1500 km) areas of unsuitable habitat. In this study, we analysed genome-scale sequence data for individuals from most of the known ice worm range. We found clear support for divergence between populations along the Pacific Coast and the inland flanks of the Coast Mountains (mean F ST = 0.60), likely precipitated by episodic ice sheet expansion and contraction during the Pleistocene. We also found support for LDD of ice worms from Alaska to Vancouver Island, perhaps mediated by migrating birds. Our results highlight the power of genomic data for disentangling complex biogeographic patterns, including the presence of LDD.

scholarly journals Global biogeographic patterns in bipolar moss species

2017 ◽  
Vol 4 (7) ◽  
pp. 170147 ◽  
Author(s):  
E. M. Biersma ◽  
J. A. Jackson ◽  
J. Hyvönen ◽  
S. Koskinen ◽  
K. Linse ◽  
...  
Keyword(s):  
Large Scale ◽  
Common Species ◽  
Long Distance Dispersal ◽  
Stepping Stones ◽  
Long Distance ◽  
Antarctic Region ◽  
Moss Species ◽  
Biogeographic Patterns ◽  
Biogeographic Pattern ◽  
The Antarctic

A bipolar disjunction is an extreme, yet common, biogeographic pattern in non-vascular plants, yet its underlying mechanisms (vicariance or long-distance dispersal), origin and timing remain poorly understood. Here, combining a large-scale population dataset and multiple dating analyses, we examine the biogeography of four bipolar Polytrichales mosses, common to the Holarctic (temperate and polar Northern Hemisphere regions) and the Antarctic region (Antarctic, sub-Antarctic, southern South America) and other Southern Hemisphere (SH) regions. Our data reveal contrasting patterns, for three species were of Holarctic origin, with subsequent dispersal to the SH, while one, currently a particularly common species in the Holarctic ( Polytrichum juniperinum ), diversified in the Antarctic region and from here colonized both the Holarctic and other SH regions. Our findings suggest long-distance dispersal as the driver of bipolar disjunctions. We find such inter-hemispheric dispersals are rare, occurring on multi-million-year timescales. High-altitude tropical populations did not act as trans-equatorial ‘stepping-stones’, but rather were derived from later dispersal events. All arrivals to the Antarctic region occurred well before the Last Glacial Maximum and previous glaciations, suggesting that, despite the harsh climate during these past glacial maxima, plants have had a much longer presence in this southern region than previously thought.

Morphological and genetic variation in disjunct populations of the avalanche lily Erythronium montanum

1996 ◽  
Vol 74 (3) ◽  
pp. 403-412 ◽  
Author(s):  
Geraldine A. Allen ◽  
Joseph A. Antos ◽  
Anne C. Worley ◽  
Terri A. Suttill ◽  
Richard J. Hebda
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Morphological Variability ◽  
Glacial Refugia ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Polymorphic Loci ◽  
Historical Factors ◽  
Disjunct Populations ◽  
Contrast Analysis

The genetic structure and morphological variability of species are influenced by both life-history traits and historical factors. We studied morphological and genetic variability in 12 populations of the avalanche lily, Erythronium montanum, representing the four disjunct regions of its geographic range in Oregon, Washington, and British Columbia. Floral traits exhibited significant differences among regions and among populations within regions, but these differences showed no clear geographic pattern, and for all traits there was substantial overlap among populations. In contrast, analysis of isozyme variation indicated a marked north–south gradient in genetic variability. The northernmost populations (from the B.C. Coast Range) had an average of 13% polymorphic loci and 1.13 alleles per locus, whereas southern populations (from the Cascade Mountains) averaged 48% polymorphic loci and 1.67 alleles per locus. The northern populations possessed no unique alleles but contained a subset of the alleles found in regions further south. We conclude that disjunct populations of E. montanum in B.C. probably arose through long-distance dispersal from more southern populations following deglaciation. Keywords: Erythronium montanum, genetic variation, glacial refugia, isozymes, long-distance dispersal, phytogeography.

Eritreo-Arabian Affinities of the Socotran Flora as Revealed from the Molecular Phylogeny of Aerva (Amaranthaceae)

2006 ◽  
Vol 31 (3) ◽  
pp. 560-570 ◽  
Author(s):  
Mike Thiv ◽  
Mats Thulin ◽  
Norbert Kilian ◽  
H. Peter Linder
Keyword(s):  
Indian Ocean ◽  
Sequence Data ◽  
Plastid Dna ◽  
Molecular Dating ◽  
Tropical Asia ◽  
Biogeographic Patterns ◽  
Dna Sequence Data ◽  
Biogeographic History ◽  
History Of ◽  
Taxonomic Groups

We investigated the colonization of the Indian Ocean archipelago of Socotra through phylogenetic analysis of Aerva (Amaranthaceae) based on nuclear and plastid DNA sequence data. The biogeographic history of the genus was tracked using ancestral area reconstructions and molecular dating. Three independent colonization lineages from the Eritreo-Arabian subregion of the Sudano-Zambesian Region were revealed: one endemic clade comprising Aerva revoluta / A. microphylla and once within A. lanata and A. javanica. Our results provide further support for the dominance of Eritreo-Arabian affinities in the flora of Socotra, in contrast to more rare affinities to Madagascar, the Mascarenes, southern Africa, and tropical Asia. Our data point towards colonization via dispersal, rather than a vicariance origin of the island elements. The overall biogeographic patterns of Aerva show only limited concordance with other taxonomic groups distributed on Indian Ocean islands.

Phylogeny and Biogeography of Acaena (Rosaceae) and its Relatives: Evidence of Multiple Long-Distance Dispersal Events Across the Globe

2021 ◽  
Vol 46 (4) ◽  
pp. 998-1010
Author(s):  
Javier Jauregui-Lazo ◽  
Daniel Potter
Keyword(s):  
South Africa ◽  
New Zealand ◽  
Southern Hemisphere ◽  
Phylogenetic Analyses ◽  
Strong Support ◽  
Disjunct Distribution ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Biogeographic Patterns ◽  
Dispersal Events

Abstract— Acaena (Rosaceae) is the most complex and ecologically variable genus in Sanguisorbinae. Although it has been the subject of several taxonomic treatments, the largest phylogenetic analysis to date only sampled a small fraction of the total global diversity (five to seven out of 45 to 50 species). This study included most of the species to elucidate the phylogenetic relationships of Acaena and biogeographic patterns in Sanguisorbinae. Phylogenetic analyses of non-coding nuclear (ITS region) and chloroplast (trnL-F) DNA sequence markers using maximum likelihood and Bayesian analyses suggested that Acaena is a paraphyletic group with species of Margyricarpus and Tetraglochin nested within it. We identified strong support for eight subclades that are geographically or taxonomically structured. Nevertheless, the species-level relationships within subclades are still uncertain, which may be due to rapid diversification and lack of informative characters in the markers used. Sanguisorbinae, a primarily Southern Hemisphere clade, exhibits a classic Gondwana disjunct distribution. This current distribution is explained primarily by eight long-distance dispersal events. Our results suggested that Sanguisorbinae split into Cliffortia and Acaena around 13.6 mya. While Cliffortia diversified in southern South Africa, Acaena experienced several migration events in the Southern Hemisphere. Our estimation of the ancestral range suggested that Acaena likely originated in South Africa, followed by migration and subsequent diversification into southern South America. From there, the genus migrated to New Zealand, throughout the Andes, and to tropical areas in Central America, reaching as far north as California. Chile and New Zealand are the main sources of propagules for dispersal as well as the greatest diversity for the genus. The evolutionary relationships of species in Acaena combine a history of rapid diversifications, long-distance dispersals, and genetic variation within some taxa. Further research should be undertaken to clarify the infraspecific classification of A. magellanica.

A new family placement for Australian blue squill, Chamaescilla: Xanthorrhoeaceae (Hemerocallidoideae), not Asparagaceae

Phytotaxa ◽  
2016 ◽  
Vol 275 (2) ◽  
pp. 97 ◽  
Author(s):  
TODD G.B. McLAY ◽  
MICHAEL J. BAYLY
Keyword(s):  
Grain Shape ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Morphological Characters ◽  
Pollen Grain ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Dna Sequence Data ◽  
New Family ◽  
Australian Family

Chamaescilla is an endemic Australian genus, currently placed in the Asparagaceae, alongside other Australian endemic taxa in the tribe Lomandroideae. A recent molecular phylogeny indicated a relationship with another partly Australian family, the Xanthorrhoeaceae, but was not commented on by the authors. Here we added DNA sequence data for a single Chamaescilla specimen to an alignment representing all families in the Asparagales and performed parsimony and Bayesian phylogenetic analyses. Chamaescilla was strongly resolved as belonging to Xanthorrhoeaceae, subfamily Hemerocallidoideae, alongside two non-Australian members, Simethis and Hemerocallis in the hemerocallid clade. This position is corroborated by morphological characters, including pollen grain shape. We also produced an age-calibrated phylogeny and infer that the geographic distribution of the clade is the result of long distance dispersal between the Eocene and Miocene.

scholarly journals Hydraulic impacts of glacier advance over a sediment bed

2006 ◽  
Vol 52 (179) ◽  
pp. 497-527 ◽  
Author(s):  
Geoffrey Boulton ◽  
Sergei Zatsepin
Keyword(s):  
Water Pressure ◽  
Ice Sheet ◽  
Pressure Transducers ◽  
Sediment Bed ◽  
Drainage Time ◽  
Glacier Ice ◽  
Ice Sheet Dynamics ◽  
Poroelastic Model ◽  
Glacier Advance ◽  
The Impact

AbstractA sedimentary sequence of till overlying a gravel aquifer was instrumented with water-pressure transducers prior to a small, anticipated surge of the margin of the glacier Breiðamerkurjökull in Iceland. The records of water pressure at each transducer site show a well-defined temporal sequence of hydraulic regimes that reflect the changing recharge of surface-derived meltwater, the pressure drop along the drainage pathway and the pattern of ice loading. The poroelastic and water-pressure response of glacially overridden sediments to the recharge rate is determined in the frequency domain through an analytic solution. This permits the in situ conductivity, compressibility and consolidation states of subglacial sediments to be derived, and reveals aquifer-scale compressibility that produces an important water-pressure wave associated with the advancing glacier. The model is then used to explore how varying conductivity/compressibility, largely determined by granulometry, can determine drainage states and instabilities that may have a large impact on glacier/ice-sheet dynamics, and how the drainage time of surface water to the bed can determine the frequency response of subglacial groundwater regimes and their influence on subglacial sediment stability. Mismatches between model predictions and specific events in water-pressure records are used to infer processes that are not incorporated in the model: hydrofracturing that changes the hydraulic properties of subglacial sediments; the impact on groundwater pressure of subglacial channel formation; upwelling beyond the glacier margin; and rapid variations in the state of consolidation. The poroelastic model also suggests how seismic methods can be developed further to monitor hydraulic conditions at the base of an ice sheet or glacier.

scholarly journals Cox2 community barcoding at Prince Edward Island reveals long-distance dispersal of a downy mildew species and potentially marine members of the Saprolegniaceae

2021 ◽  
Vol 20 (4) ◽  
pp. 509-516
Author(s):  
Julia A. F. Langer ◽  
Rahul Sharma ◽  
Bora Nam ◽  
Louis Hanic ◽  
Maarten Boersma ◽  
...  
Keyword(s):  
Prince Edward Island ◽  
Sequence Data ◽  
Marine Species ◽  
Global Ocean ◽  
Plankton Sample ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Marine Food Webs ◽  
Bona Fide ◽  
Globally Distributed

AbstractMarine oomycetes are highly diverse, globally distributed, and play key roles in marine food webs as decomposers, food source, and parasites. Despite their potential importance in global ocean ecosystems, marine oomycetes are comparatively little studied. Here, we tested if the primer pair cox2F_Hud and cox2-RC4, which is already well-established for phylogenetic investigations of terrestrial oomycetes, can also be used for high-throughput community barcoding. Community barcoding of a plankton sample from Brudenell River (Prince Edward Island, Canada), revealed six distinct oomycete OTU clusters. Two of these clusters corresponded to members of the Peronosporaceae—one could be assigned to Peronospora verna, an obligate biotrophic pathogen of the terrestrial plant Veronica serpyllifolia and related species, the other was closely related to Globisporangium rostratum. While the detection of the former in the sample is likely due to long-distance dispersal from the island, the latter might be a bona fide marine species, as several cultivable species of the Peronosporaceae are known to withstand high salt concentrations. Two OTU lineages could be assigned to the Saprolegniaceae. While these might represent marine species of the otherwise terrestrial genus, it is also conceivable that they were introduced on detritus from the island. Two additional OTU clusters were grouped with the early-diverging oomycete lineages but could not be assigned to a specific family. This reflects the current underrepresentation of cox2 sequence data which will hopefully improve with the increasing interest in marine oomycetes.

scholarly journals Long-distance dispersal shaped the diversity of tribe Dorstenieae (Moraceae)

2019 ◽  
Author(s):  
Qian Zhang ◽  
Elliot Gardner ◽  
Nyree Zerega ◽  
Hervé Sauquet
Keyword(s):  
Long Distance Dispersal ◽  
Crown Group ◽  
Long Distance ◽  
Data Set ◽  
Origin And Evolution ◽  
Biogeographic History ◽  
Joint Area ◽  
Model Clade ◽  
Terrestrial Biodiversity ◽  
Bayesian Relaxed Clock

AbstractAimThe Neotropics have the highest terrestrial biodiversity on earth. Investigating the relationships between the floras of the Neotropics and other tropical areas is critical to understanding the origin and evolution of this mega-diverse region. Tribe Dorstenieae (Moraceae) has a pantropical distribution and almost equal number of species on both sides of the Atlantic. In this study, we investigate the relationship between the African and Neotropical floras using Dorstenieae (15 genera, 156 species, Moraceae) as a model clade.Locationthe Neotropics and Africa.MethodsWe used a targeted enrichment strategy with herbarium samples and a nuclear bait set to assemble a data set of 102 genes sampled from 83 (53%) species and fifteen genera (100%) of Dorstenieae, and five outgroup species. Phylogenetic relationships were reconstructed with maximum likelihood and coalescent approaches. This phylogeny was dated with a Bayesian relaxed clock model and four fossil calibrations. The biogeographic history of the group was then reconstructed with several dispersal-extinction-cladogenesis models (incl. DEC and DEC+J).ResultsThe crown-group ages of Dorstenieae and Dorstenia were estimated in the Cretaceous (65.8-79.8 Ma) and the Paleocene (50.8-67.3 Ma), respectively. Tribe Dorstenieae as a whole appears to have originated in the joint area of continental Africa, Madagascar and Asia-Oceania area. The Neotropical species of Dorstenia diversified in the Eocene (29.8-44.7 Ma) and formed a clade nested within the African lineages in the genus. Brosimum s.l., with a crown-group age at the period of the Oligocene and Miocene (14.9-31.1 Ma), represents another Neotropical clade in Dorstenieae.Main conclusionsTribe Dorstenieae originated in the joint area of continental Africa, Madagascar and Asia-Oceania area in the Cretaceous and then dispersed into Neotropics twice. Neotropical diversification after long-distance dispersal across the Atlantic is the most plausible explanation for the extant distribution pattern of Dorstenieae.

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