Population genetics of Melaleuca irbyana (Myrtaceae) the ‘swamp tea tree’ and implications for its conservation and restoration

2018 ◽  
Vol 66 (1) ◽  
pp. 13 ◽  
Author(s):  
Reuben Burrough ◽  
Gabriel Conroy ◽  
Robert W. Lamont ◽  
Yoko Shimizu-Kimura ◽  
Alison Shapcott
Keyword(s):  
Genetic Diversity ◽  
Land Use ◽  
Population Genetics ◽  
Genetic Information ◽  
Patch Size ◽  
Isolated Populations ◽  
Tea Tree ◽  
Human Land Use ◽  
Disjunct Populations ◽  
Geographic Regions

Habitat fragmentation is affecting greater numbers of species as human land use requirements increase. Melaleuca irbyana R.T.Baker (Myrtaceae) is an endangered tea tree which dominates critically endangered, south-east Queensland swamp tea tree forest. It is restricted to isolated populations in south-east Queensland. New disjunct populations have recently been found adjacent to gas pipeline developments in the Brigalow Belt in central Queensland. A population genetics study was undertaken on the species to investigate its diversity to advise conservation and restoration. Primers for microsatellite markers were developed and used to provide the genetic information for the study. M. irbyana was found to possess moderate levels of genetic diversity within populations but this was not correlated with patch size or isolation. However, inbreeding levels were moderately high in all populations, suggesting individuals may be self-fertilised as there was no evidence of clonality detected in this species despite evidence of resprouting. The disjunct populations in central Queensland were genetically distinct, which highlights their importance for conservation of the species. The northern NSW populations are potentially at risk as they are depauperate and genetically distinct. There is differentiation among populations between the geographic regions so care should be taken to consider local provenance in restoration plantings.

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.

Partial and complete leucism in two Abrothrix species (Rodentia: Cricetidae) from central Chile

Mammalia ◽  
2018 ◽  
Vol 83 (1) ◽  
pp. 100-102 ◽  
Author(s):  
André V. Rubio ◽  
Javier A. Simonetti
Keyword(s):  
Genetic Diversity ◽  
Land Use ◽  
Land Use Change ◽  
First Record ◽  
Neotropical Region ◽  
Pine Plantations ◽  
Rodent Species ◽  
Isolated Populations ◽  
Central Chile ◽  
Field Surveys

Abstract Rodents with leucism (a hypopigmentary congenital disorder) in the Neotropical region are rarely recorded. During field surveys in central Chile, we found in commercial Monterrey pine plantations a specimen of Abrothrix longipilis and a specimen of Abrothrix olivaceus with partial leucism. Another A. olivaceus exhibited complete leucism. To our knowledge, this is the second documentation of leucism in rodents from Chile and the first record of leucism in A. longipilis. Leucism may be expressed in small and isolated populations due to inbreeding. This suggests that land-use change in this area is probably affecting the genetic diversity of these rodent species.

scholarly journals Whole genome sequencing reveals high differentiation, low levels of genetic diversity and short runs of homozygosity among Swedish wels catfish

Heredity ◽  
2021 ◽  
Author(s):  
Axel Jensen ◽  
Mette Lillie ◽  
Kristofer Bergström ◽  
Per Larsson ◽  
Jacob Höglund
Keyword(s):  
Genetic Diversity ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Whole Genome Sequencing Data ◽  
Peripheral Populations ◽  
Whole Genome ◽  
Runs Of Homozygosity ◽  
Sequencing Data ◽  
Isolated Populations ◽  
Native Populations

AbstractThe use of genetic markers in the context of conservation is largely being outcompeted by whole-genome data. Comparative studies between the two are sparse, and the knowledge about potential effects of this methodology shift is limited. Here, we used whole-genome sequencing data to assess the genetic status of peripheral populations of the wels catfish (Silurus glanis), and discuss the results in light of a recent microsatellite study of the same populations. The Swedish populations of the wels catfish have suffered from severe declines during the last centuries and persists in only a few isolated water systems. Fragmented populations generally are at greater risk of extinction, for example due to loss of genetic diversity, and may thus require conservation actions. We sequenced individuals from the three remaining native populations (Båven, Emån, and Möckeln) and one reintroduced population of admixed origin (Helge å), and found that genetic diversity was highest in Emån but low overall, with strong differentiation among the populations. No signature of recent inbreeding was found, but a considerable number of short runs of homozygosity were present in all populations, likely linked to historically small population sizes and bottleneck events. Genetic substructure within any of the native populations was at best weak. Individuals from the admixed population Helge å shared most genetic ancestry with the Båven population (72%). Our results are largely in agreement with the microsatellite study, and stresses the need to protect these isolated populations at the northern edge of the distribution of the species.

scholarly journals Small population size and low genomic diversity have no effect on fitness in experimental translocations of a wild fish

2019 ◽  
Vol 286 (1916) ◽  
pp. 20191989 ◽  
Author(s):  
M. C. Yates ◽  
E. Bowles ◽  
D. J. Fraser
Keyword(s):  
Genetic Diversity ◽  
Body Size ◽  
Population Size ◽  
Brook Trout ◽  
Habitat Degradation ◽  
Species Conservation ◽  
Empirical Work ◽  
Genomic Diversity ◽  
Effective Population ◽  
Isolated Populations

Little empirical work in nature has quantified how wild populations with varying effective population sizes and genetic diversity perform when exposed to a gradient of ecologically important environmental conditions. To achieve this, juvenile brook trout from 12 isolated populations or closed metapopulations that differ substantially in population size and genetic diversity were transplanted to previously fishless ponds spanning a wide gradient of ecologically important variables. We evaluated the effect of genome-wide variation, effective population size ( N e ), pond habitat, and initial body size on two fitness correlates (survival and growth). Genetic variables had no effect on either fitness correlate, which was determined primarily by habitat (pond temperature, depth, and pH) and initial body size. These results suggest that some vertebrate populations with low genomic diversity, low N e , and long-term isolation can represent important sources of variation and are capable of maintaining fitness in, and ultimately persisting and adapting to, changing environments. Our results also reinforce the paramount importance of improving available habitat and slowing habitat degradation for species conservation.

scholarly journals Effects of habitat structure and land-use intensity on the genetic structure of the grasshopper species Chorthippus parallelus

2014 ◽  
Vol 1 (2) ◽  
pp. 140133 ◽  
Author(s):  
Kerstin R. Wiesner ◽  
Jan Christian Habel ◽  
Martin M. Gossner ◽  
Hugh D. Loxdale ◽  
Günter Köhler ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Land Use ◽  
Genetic Structure ◽  
Sampling Site ◽  
Land Use Intensity ◽  
Habitat Size ◽  
Grasshopper Species ◽  
Chorthippus Parallelus ◽  
Landscape Characteristics ◽  
Local Populations

Land-use intensity (LUI) is assumed to impact the genetic structure of organisms. While effects of landscape structure on the genetics of local populations have frequently been analysed, potential effects of variation in LUI on the genetic diversity of local populations have mostly been neglected. In this study, we used six polymorphic microsatellites to analyse the genetic effects of variation in land use in the highly abundant grasshopper Chorthippus parallelus . We sampled a total of 610 individuals at 22 heterogeneous grassland sites in the Hainich-Dün region of Central Germany. For each of these grassland sites we assessed habitat size, LUI (combined index of mowing, grazing and fertilization), and the proportion of grassland adjoining the sampling site and the landscape heterogeneity (the latter two factors within a 500 m buffer zone surrounding each focal site). We found only marginal genetic differentiation among all local populations and no correlation between geographical and genetic distance. Habitat size, LUI and landscape characteristics had only weak effects on most of the parameters of genetic diversity of C. parallelus ; only expected heterozygosity and the grasshopper abundances were affected by interacting effects of LUI, habitat size and landscape characteristics. The lack of any strong relationships between LUI, abundance and the genetic structure might be due to large local populations of the species in the landscape, counteracting local differentiation and potential genetic drift effects.

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