On the persistence and dispersal of transantarctic Hepaticae

1979 ◽  
Vol 57 (20) ◽  
pp. 2179-2225 ◽  
Author(s):  
Rudolf M. Schuster
Keyword(s):  
Gene Flow ◽  
Southern Hemisphere ◽  
Short Range ◽  
Distribution Patterns ◽  
Disjunct Distribution ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Disjunct Populations ◽  
Geological Background

The dispersal of a considerable number, if not the vast majority, of southern hemisphere Hepaticae chiefly belonging to "old" families and suborders can be visualized as resulting primarily from short-range or "step-wise" dispersal, as part of structural communities, before the final disassembly of the presently fragmented Gondwanaland. Often with the disruption of gene flow, disjunct populations of once continuously distributed Gondwanalandic taxa have undergone speciation, in most cases as physical disruption occurred. Significant relict and disjunct distribution patterns for 21 hepatic taxa are mapped and discussed. A discussion of (i) rate of speciation and genus formation, (ii) efficiency of long-distance dispersal, and (iii) the geological background is presented with the purpose of explaining the origins of antipodal distribution patterns within the Hepaticae.

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 freshwater species of the genus Dolops (Crustacea : Branchiura) parasitic on a galaxiid fish of Tasmania - with comments on disjunct distribution patterns in the southern hemisphere

1969 ◽  
Vol 17 (1) ◽  
pp. 49 ◽  
Author(s):  
G Fryer
Keyword(s):  
New Species ◽  
Southern Hemisphere ◽  
Continental Drift ◽  
Distribution Patterns ◽  
Disjunct Distribution ◽  
Freshwater Species ◽  
Bivalve Molluscs ◽  
Freshwater Bivalve ◽  
A New Species

A new species of Dolops is described from Lake Surprise, Tasmania, where it has been found on a galaxiid fish. Hitherto the genus has been known only from freshwater in S. America and Africa. Taxonomic errors involving an alleged Asiatic member of the genus are rectified and recent gross mistreatment of the classification of the Branchiura is discussed. The genus Dolops is re-defined. Evidence bearing on the history and dispersal of Dolops and other organisms is reviewed, particular attention being directed to the freshwater bivalve molluscs formerly assigned to the Mutelidae. While the African and S. American muteloids belong to closely related families of the Muteloidea, the Australasian forms formerly thought of as representatives of this group have no place in this superfamily. They, and certain S. American bivalves, however, show unambiguous trans-Antarctic affinities as they belong to a common family, the Hyriidae. Taking into account recent work, both geological and biological, and in spite of powerful voices raised in objection, the disjunct distribution of several groups of animals in the Southern Hemisphere seems to be most plausibly explained as a result of continental drift, though no dogmatic claims are made.

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.

scholarly journals An Evolutionary Study of Carex Subg. Psyllophorae (Cyperaceae) Sheds Light on a Strikingly Disjunct Distribution in the Southern Hemisphere, With Emphasis on Its Patagonian Diversification

2021 ◽  
Vol 12 ◽  
Author(s):  
Carmen Benítez-Benítez ◽  
Ana Otero ◽  
Kerry A. Ford ◽  
Pablo García-Moro ◽  
Sabina Donadío ◽  
...  
Keyword(s):  
General Pattern ◽  
Disjunct Distribution ◽  
Divergence Times ◽  
Species Number ◽  
Primary Role ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Diversification Rates ◽  
Sw Pacific ◽  
Western Palearctic

Carex subgenus Psyllophorae is an engaging study group due to its early diversification compared to most Carex lineages, and its remarkable disjunct distribution in four continents corresponding to three independent sections: sect. Psyllophorae in Western Palearctic, sect. Schoenoxiphium in Afrotropical region, and sect. Junciformes in South America (SA) and SW Pacific. The latter section is mainly distributed in Patagonia and the Andes, where it is one of the few Carex groups with a significant in situ diversification. We assess the role of historical geo-climatic events in the evolutionary history of the group, particularly intercontinental colonization events and diversification processes, with an emphasis on SA. We performed an integrative study using phylogenetic (four DNA regions), divergence times, diversification rates, biogeographic reconstruction, and bioclimatic niche evolution analyses. The crown age of subg. Psyllophorae (early Miocene) supports this lineage as one of the oldest within Carex. The diversification rate probably decreased over time in the whole subgenus. Geography seems to have played a primary role in the diversification of subg. Psyllophorae. Inferred divergence times imply a diversification scenario away from primary Gondwanan vicariance hypotheses and suggest long-distance dispersal-mediated allopatric diversification. Section Junciformes remained in Northern Patagonia since its divergence until Plio-Pleistocene glaciations. Andean orogeny appears to have acted as a northward corridor, which contrasts with the general pattern of North-to-South migration for temperate-adapted organisms. A striking niche conservatism characterizes the evolution of this section. Colonization of the SW Pacific took place on a single long-distance dispersal event from SA. The little ecological changes involved in the trans-Pacific disjunction imply the preadaptation of the group prior to the colonization of the SW Pacific. The high species number of the section results from simple accumulation of morphological changes (disparification), rather than shifts in ecological niche related to increased diversification rates (radiation).

scholarly journals Hawkmoth Pollination Facilitates Long-distance Pollen Dispersal and Reduces Isolation Across a Gradient of Land-use Change

2019 ◽  
Vol 104 (3) ◽  
pp. 495-511 ◽  
Author(s):  
Krissa A. Skogen ◽  
Rick P. Overson ◽  
Evan T. Hilpman ◽  
Jeremie B. Fant
Keyword(s):  
Land Use ◽  
Gene Flow ◽  
Habitat Fragmentation ◽  
Land Use Change ◽  
Pollen Dispersal ◽  
Suitable Habitat ◽  
Long Distance Dispersal ◽  
Effective Population ◽  
Long Distance ◽  
Genetic Diversity And Structure

Land-use change is among the top drivers of global biodiversity loss, which impacts the arrangement and distribution of suitable habitat for species. Population-level effects include increased isolation, decreased population size, and changes to mutualistic and antagonistic interactions. However, the extent to which species are impacted is determined by life history characteristics including dispersal. In plants, mating dynamics can be changed in ways that can negatively impact population persistence if dispersal of pollen and/or seed is disrupted. Long-distance dispersal has the potential to buffer species from the negative impacts of land-use change. Biotic vectors of long-distance dispersal have been less frequently studied, though specific taxa are known to travel great distances. Here, we describe population genetic diversity and structure in a sphingophilous species that is experiencing habitat fragmentation through land-use change, Oenothera harringtonii W. L. Wagner, Stockh. & W. M. Klein (Onagraceae). We use 12 nuclear and four plastid microsatellite markers and show that pollen dispersal by hawkmoths drives high gene flow and low population differentiation despite a range-wide gradient of land-use change and habitat fragmentation. By separating the contributions of pollen and seed dispersal to gene flow, we show that most of the genetic parameters are driven by hawkmoth-facilitated long-distance pollen dispersal, but populations with small, effective population sizes experience higher levels of relatedness and inbreeding. We discuss considerations for conservation efforts for this and other species that are pollinated by long-distance dispersers.

Floristics of the South American Páramo Moss Flora

1990 ◽  
Vol 2 (1) ◽  
pp. 127-132
Author(s):  
Dana Griffin III
Keyword(s):  
South America ◽  
Southern Hemisphere ◽  
Cloud Forest ◽  
South American ◽  
Long Distance Dispersal ◽  
The South ◽  
Long Distance ◽  
Late Pliocene ◽  
Northern Andes ◽  
The Past

The South American paramos appeared in Pliocene times and persist to the present day. The moss flora of this habitat consists of an estimated 400 species that comprise 8 floristic groups. In Venezuela these groups and their percent representation are as follows: neotropical 37%, Andean 26%, cosmopolitan 18%, Andean-African 8%, neotropical-Asiatic 3%, neotropical-Australasian 2%, temperate Southern Hemisphere 2% and northern boreal-temperate 2%. Acrocarpous taxa outnumber pleurocarps by nearly 3:1. The neotropical and Andean floristic stocks likely were present prior to late Pliocene orogenies that elevated the cordillera above climatic timberlines. These species may have existed in open, marshy areas (paramillos) or may have evolved from cloud forest ancestors. Taxa of northern boreal- temperate affinities, including those with Asiatic distributions, probably arrived in the paramos during the Pleistocene, a period which may also have seen the establishment in the Northern Andes of some cosmopolitan elements. Species with temperate Southern Hemisphere and Australasian affinities likely spread first to austral South America thence migrated northward during a cool, moist interval sometime over the past 2.5-3 million years or may have become established in the paramos as a result of long- distance dispersal.

scholarly journals Evidence of avian-mediated long distance dispersal in American tardigrades

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5035 ◽  
Author(s):  
Matthew J. Mogle ◽  
Scott A. Kimball ◽  
William R. Miller ◽  
Richard D. McKown
Keyword(s):  
Bird Species ◽  
Distribution Patterns ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Neotropical Migrant ◽  
Grus Canadensis ◽  
Sandhill Crane ◽  
Migrant Birds ◽  
North And South

Terrestrial tardigrades, commonly known as “water bears”, are part of a phylum of microscopic, aquatic invertebrates famous for cryptobiosis and space travel, but little is known about their modes of dispersal on Earth. Wind is assumed, but not truly demonstrated, to be the major method of global dispersal. Yet, some water bear distribution patterns cannot be explained by patterns of prevailing winds. Mammals and birds have been proposed as potential animal vectors. Importantly, most nearctic-neotropical migrant birds move north and south, with many crossing the equator, whereas prevailing winds move west to east or east to west but do not cross the equator. When multiplied by billions of birds over tens of millions of years, if the ectozoochory of tardigrades by birds is true then both regional and intercontinental patterns can be better explained. To test for the potential role of birds in tardigrade dispersal, the nests of 10 species for birds were examined. Seventy percent of nests were positive for tardigrades, demonstrating that some birds are in a position for transference. The carcasses of eight birds (six species) found dead from window strikes and a Sandhill Crane (Grus canadensis) found dead during routine surveys were also examined. Of the birds examined, 66% yielded tardigrades from two classes, three orders, and five species, including juveniles, adults, and eggs, suggesting that many bird species are potential vectors for many species of tardigrades. Our data support the hypothesis of avian-mediated long distance dispersal of tardigrades and provide evidence that further investigation is warranted.

scholarly journals Sexual Reproduction and Gene Flow in the Pine Pathogen Dothistroma septosporum in British Columbia

2011 ◽  
Vol 101 (1) ◽  
pp. 68-76 ◽  
Author(s):  
A. L. Dale ◽  
K. J. Lewis ◽  
B. W. Murray
Keyword(s):  
British Columbia ◽  
Gene Flow ◽  
Sexual Reproduction ◽  
Mating Type ◽  
Random Mating ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Data Set ◽  
Haplotypic Diversity ◽  
Dothistroma Septosporum

Dothistroma septosporum has caused a serious needle blight epidemic in the lodgepole pine forests in northwest British Columbia over the past several years. Although ascocarps had been observed in British Columbia, nothing was known about the contribution of sexual reproduction, gene flow and long-distance dispersal to the epidemic. Amplified fragment length polymorphism and mating-type markers in 19 sites were used to generate population and reproductive data. Overall, evidence suggests a mixed mode of reproduction. Haplotypic diversity was high, with 79 unique and 56 shared haplotypes (possible clones) identified from 192 fungal isolates. Overall, mating-type segregation did not differ significantly from 1:1; however, random mating was rejected in most populations in the index of association and parsimony tree-length permutation analyses using the full data set and, when using clone-corrected data sets, more of the smaller populations showed random mating. Two of the smaller populations consistently showed random mating for both tests using both clone-corrected and noncorrected data. High gene flow is suggested by no differentiation between 14 of the 19 sites, several of which came from young plantations where the pathogen was not likely present prior to the current outbreak. The remaining five sites showed some level of divergence, possibly due to historic separation and endemic pathogen populations. Results indicate a high evolutionary potential and long-distance dispersal in this pathogen, important to consider in future forest management.

scholarly journals Genetic variation in the emblematic Puya raimondii (Bromeliaceae) from Huascarán National Park, Peru

2013 ◽  
Vol 13 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Claudia Teresa Hornung-Leoni ◽  
Victoria Sosa ◽  
June Simpson ◽  
Katia Gil
Keyword(s):  
Genetic Diversity ◽  
Cluster Analysis ◽  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Variability ◽  
National Park ◽  
Conservation Strategies ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Mountain Systems

Puya raimondii, the giant Peruvian and Bolivian terrestrial bromeliad, is an emblematic endemic Andean species well represented in Huascarán National Park in Peru. This park is the largest reserve of puna (high altitude plateau) vegetation. The objective of this study is to report on genetic variation in populations of P. raimondii from Huascarán and neighboring areas. AFLP profiles with four selective primer combinations were retrieved for 60 individuals from different zones. Genetic variability was estimated and a total of 172 bands were detected, of which 79.1% were polymorphic loci. The results showed genetic differentiation among populations, and gene flow. A cluster analysis showed that individuals of P. raimondii populations located in different mountain systems could be grouped together, suggesting long distance dispersal. Thus, conservation strategies for P. raimondii have to take into account exchange between populations located far apart in distance in order to preserve the genetic diversity of this showy species.

Do lowland habitats represent barriers to dispersal for a rainforest mayfly, Bungona narilla, in south-east Queensland?

2008 ◽  
Vol 59 (9) ◽  
pp. 761 ◽  
Author(s):  
Alison J. McLean ◽  
Daniel J. Schmidt ◽  
Jane M. Hughes
Keyword(s):  
Gene Flow ◽  
Aquatic Insect ◽  
Restricted Gene Flow ◽  
Long Distance Dispersal ◽  
Genetic Structuring ◽  
Long Distance ◽  
Heterogeneous Landscapes ◽  
Insect Populations ◽  
Dispersal Events ◽  
The Relationship

Long-distance dispersal might be an important mechanism for the maintenance of aquatic insect populations in heterogeneous landscapes. However, these events can be difficult to measure by direct observation because the techniques can be time-consuming, expensive and technically difficult. When dispersal results in gene flow within and between populations, patterns of variation can be detected by genetic methods. The levels of population genetic structuring and the relationship between gene flow and geographical distance were assessed in the mayfly species Bungona narilla (Harker, 1957) in rainforest streams in south-east Queensland that are separated by lowland habitats. An analysis of molecular variance based on mitochondrial DNA data, using a fragment of the cytochrome oxidase I gene, revealed significant differentiation between regions, suggesting that maternal gene flow was restricted. A nested clade analysis revealed patterns of historical (contiguous) range expansions and recent restricted gene flow along with some long-distance dispersal events. Our analyses have shown that populations of B. narilla are significantly structured throughout the species range in south-east Queensland and that the low elevation habitats separating the northern and southern populations are restricting gene flow to some extent.

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