Microsatellite and cpDNA variation in island and mainland populations of a regionally rare eucalypt, Eucalyptus perriniana (Myrtaceae)

2007 ◽  
Vol 55 (5) ◽  
pp. 513 ◽  
Author(s):  
Damien A. Rathbone ◽  
Gay E. McKinnon ◽  
Brad M. Potts ◽  
Dorothy A. Steane ◽  
René E. Vaillancourt
Keyword(s):  
Genetic Diversity ◽  
Chloroplast Dna ◽  
Dna Marker ◽  
Isolated Populations ◽  
South Eastern ◽  
Eucalypt Species ◽  
Eastern Australia ◽  
Population Sizes ◽  
Nuclear Microsatellite ◽  
Geographic Separation

Eucalyptus perriniana F.Muell. ex Rodway is distributed over a wide geographic range in south-eastern Australia as a series of small and isolated populations. In Tasmania, there are only three known populations that are separated by 511 km from the closest population on mainland Australia, which is one of the largest disjunctions observed for any eucalypt species. This project utilised eight nuclear microsatellites and one chloroplast DNA marker to study the genetic diversity in E. perriniana and determine the affinities between the populations. In all, 302 individuals in nine populations across the whole range of the species were sampled. The overall nuclear microsatellite diversity in E. perriniana (Ht = 0.85), as well as the diversity in each population (He = 0.73), was comparable to that found in widespread eucalypt species that have much larger population sizes. The microsatellites revealed that the isolated Tasmanian populations were significantly differentiated from mainland populations (FST between regions = 0.08), although the mainland Baw Baw population was the most differentiated. Most populations harboured different chloroplast DNA haplotypes, but in general, there were more mutational differences among haplotypes found in Tasmania than between Tasmanian and mainland populations. The Tasmanian populations often shared chloroplast DNA haplotypes with other eucalypts from south-eastern Tasmania. In conclusion, the populations of E. perriniana are genetically variable and significantly differentiated, with geographic separation being a poor predictor of the amount of genetic divergence. The most divergent populations are those in Tasmania and on Mt Baw Baw and their conservation is important to capture the genetic diversity in the species.

The Conservation Genetics of Eucalyptus paliformis L. Johnson et Blaxell and E. parvifolia Cambage, Two Rare Species From South-Eastern Australia

1990 ◽  
Vol 38 (1) ◽  
pp. 79 ◽  
Author(s):  
SM Prober ◽  
C Tompkins ◽  
GF Moran ◽  
JC Bell
Keyword(s):  
Genetic Diversity ◽  
Narrow Band ◽  
Large Population ◽  
Continuous Distribution ◽  
Allozyme Diversity ◽  
Grazing Land ◽  
South Eastern ◽  
Eastern Australia ◽  
Population Sizes ◽  
South Eastern Australia

Eucalyptus paliformis is restricted to a small, isolated plateau on the eastern escarpment of south-eastern Australia. Eucalyptus parvifolia populations are scattered discontinuously in a narrow band of nearby grazing land that has been substantially cleared over the last 100 years. Allozyme diversity was examined in six of the seven known populations of E. paliformis and in all the eight known populations of E. parvifolia to help assess the potential for the survival of these species under current conditions of management. Levels of genetic diversity in E. paliformis are comparable to levels in other eucalypts of restricted distribution and, in conjunction with its large population sizes, are likely to be adequate for its survival. The greatest threat to E. paliformis is its localised distribution, which renders it susceptible to extinction by disturbance. By contrast, the levels and distribution of diversity in E. parvifolia, and estimates of migration between populations, suggest that the high variability measured in this species may be a consequence of a once more continuous distribution. The recent dissection of its range through clearing is likely to lead to a decline in levels of genetic diversity in E. parvifolia, which, when combined with destruction of the habitat where it can best outcompete other eucalypts, suggests its survival is threatened.

scholarly journals Sporadic Genetic Connectivity among Small Insular Populations of the Rare Geoendemic Plant Caulanthus amplexicaulis var. barbarae (Santa Barbara Jewelflower)

2019 ◽  
Vol 110 (5) ◽  
pp. 587-600
Author(s):  
A Millie Burrell ◽  
Jeffrey H R Goddard ◽  
Paul J Greer ◽  
Ryan J Williams ◽  
Alan E Pepper
Keyword(s):  
Gene Flow ◽  
Genetic Connectivity ◽  
Effective Population ◽  
Evolutionary Potential ◽  
Isolated Populations ◽  
Long Distance ◽  
Population Sizes ◽  
History Of ◽  
Small Set ◽  
Nuclear Microsatellite

Abstract Globally, a small number of plants have adapted to terrestrial outcroppings of serpentine geology, which are characterized by soils with low levels of essential mineral nutrients (N, P, K, Ca, Mo) and toxic levels of heavy metals (Ni, Cr, Co). Paradoxically, many of these plants are restricted to this harsh environment. Caulanthus ampexlicaulis var. barbarae (Brassicaceae) is a rare annual plant that is strictly endemic to a small set of isolated serpentine outcrops in the coastal mountains of central California. The goals of the work presented here were to 1) determine the patterns of genetic connectivity among all known populations of C. ampexlicaulis var. barbarae, and 2) estimate contemporary effective population sizes (Ne), to inform ongoing genomic analyses of the evolutionary history of this taxon, and to provide a foundation upon which to model its future evolutionary potential and long-term viability in a changing environment. Eleven populations of this taxon were sampled, and population-genetic parameters were estimated using 11 nuclear microsatellite markers. Contemporary effective population sizes were estimated using multiple methods and found to be strikingly small (typically Ne < 10). Further, our data showed that a substantial component of genetic connectivity of this taxon is not at equilibrium, and instead showed sporadic gene flow. Several lines of evidence indicate that gene flow between isolated populations is maintained through long-distance seed dispersal (e.g., >1 km), possibly via zoochory.

scholarly journals Defining intraspecific conservation units in the endemic Cuban Rock Iguanas (Cyclura nubila nubila)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kyle J. Shaney ◽  
L. Grisell Diaz-Ramirez ◽  
Sayra Espindola ◽  
Susette Castañeda-Rico ◽  
Vicente Berovides-Álvarez ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Effective Population ◽  
Conservation Units ◽  
Declining Populations ◽  
Nuclear Microsatellite ◽  
Geographic Separation ◽  
Negative Impacts ◽  
Time Of Divergence ◽  
East West

AbstractDefining conservation units is an important step in species management and requires interpretation of the genetic diversity and ecological function of the taxon being considered. We used the endemic Cuban Rock Iguanas (Cyclura nubila nubila) as a model to highlight this challenge and examined patterns of its intraspecific genetic diversity across Cuba. We evaluated nuclear (microsatellite loci) and mitochondrial diversity across eight populations from the island and its off-shore cays, and applied the population genetics results for assignment of Management Unit (MU) status and Evolutionary Significant Units (ESUs) based on phylogeographic and time of divergence information. We identified at least six distinct Cuban Rock Iguana MUs, encompassing demographically isolated and genetically differentiated populations across Cuba, most with low effective population size, declining populations, and with high risk of inbreeding and genetic drift. Hence, each MU should be considered of urgent conservation priority. Given the key ecological seed dispersal role of C. n. nubila, the disappearance of any MU could trigger the loss of local ecological functional diversity and major negative impacts on their ecosystems. Two divergent ESUs were also identified, exhibiting an historical east–west geographic separation on Cuba. Based on a Caribbean phylogeographic assessment, our findings strengthen the conclusion that all geographically and evolutionarily differentiated Cyclura species and subspecies across the archipelago warrant ESU distinction.

Patterns of Genetic Diversity and Nature of the Breeding System in Melaleuca alternifolia (Myrtaceae)

1992 ◽  
Vol 40 (3) ◽  
pp. 365 ◽  
Author(s):  
PA Butcher ◽  
JC Bell ◽  
GF Moran
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Distance Measures ◽  
Melaleuca Alternifolia ◽  
Isolated Populations ◽  
Tea Tree ◽  
South Wales ◽  
Baseline Information ◽  
Geographic Separation ◽  
Natural Stands

Melaleuca alternifolia (Maiden & Betche) Cheel is harvested from natural stands and plantations for production of Australian tea-tree oil. Genetic variation was examined and outcrossing rates estimated to provide baseline information for breeding and selection programs. The overall genetic diversity (HT = 0.186) is comparable to other regionally distributed Australian tree species. There was a general trend for more isolated populations to have less genetic variation than populations from the centre of the species distribution. The level of differentiation among populations was low (12%), associated with a high outcrossing rate (93%) and high levels of gene flow. Geographic separation of Queensland and New South Wales populations corresponds with genetic distance measures.

Development of the egg if the stick insect Didyuris violescens with particular reference to diapause

1971 ◽  
Vol 19 (2) ◽  
pp. 141 ◽  
Author(s):  
JL Readshaw ◽  
GO Bedford
Keyword(s):  
Strong Support ◽  
Stick Insect ◽  
Isolated Populations ◽  
South Eastern ◽  
Eastern Australia ◽  
Outbreak Areas ◽  
Geographic Populations ◽  
Cool Summer ◽  
Diapause Development ◽  
South Eastern Australia

The paper provides a comprehensive account of the development of the egg of the phasmatid D, violescens, a serious defoliator of Euca~ptus forests in the highlands of south-eastern Australia. The occurrence of parthenogenesis and the incidence of the two diapauses are compared in several spatially isolated populations. The observed differences are consistent with the hypothesis that D. violescens has tended to lose its capability for parthenogenesis while developing its competence for diapause as the species extended its range from subtropical to temperate regions. This hypothesis receives strong support from a recent discovery that there are at least seven genetically distinct races of D. violescens in south-eastern Australia. The influence of constant temperatures on diapause development and embryogenesis is described for several geographic populations. Irrespective of the origin of the populations, the optimum temperature for diapause development is about 2"C, and embryogenesis proceeds more rapidly as temperatures increase from a lower threshold of about 7" to 27�C. Both processes can occur simultaneously at temperatures between the two optima. The following section shows the total effect of genotype and environment on the pattern of development and hatching in the field. In the southern outbreak areas the populations are of two kinds: highland populations, in which the occurrence of the two diapauses ensures that the eggs overwinter at least twice before hatching; and foothill populations, where the absence of the first diapause means that the eggs may overwinter either once or twice before hatching, depending on when they were laid during the summer. This partly explains how a particularly cool summer can initiate the 2-year cycling of population which is the most obvious characteristic of the outbreaks of D, violescens in south-eastern Australia.

Rhizo-Stolons in Eucalyptus

1980 ◽  
Vol 28 (3) ◽  
pp. 299 ◽  
Author(s):  
AN Gillison ◽  
CJ Lacey ◽  
RH Bennett
Keyword(s):  
Field Observations ◽  
South Eastern ◽  
Eucalypt Species ◽  
Eastern Australia ◽  
South Eastern Australia

A previously unrecorded system of eucalypt regeneration, via stolons and rhizo-stolons, is reported for field populations of shrub-like forms of grey box (Eucalyptus moluccana Roxb. subsp. moluccana) in south- eastern Australia. Field collections of rooted stoloniferous material were transplanted into artificial media under controlled glasshouse conditions where they produced similar rhizomes and extensive plagiotropic branching. Similar field observations in E. stellulata populations suggest that this clonal phenomenon may be present in other eucalypt species and could have significant implications for research and management.

Sign in / Sign up

Export Citation Format

Share Document