Genetic Differentiation in Isolated Populations of Hakea carinata (Proteaceae)

1998 ◽  
Vol 46 (6) ◽  
pp. 671 ◽  
Author(s):  
G. J. Starr ◽  
S. M. Carthew
Keyword(s):  
Gene Flow ◽  
Habitat Fragmentation ◽  
Gene Diversity ◽  
South Australia ◽  
Similar Species ◽  
Isolated Populations ◽  
Plant Populations ◽  
Evolutionary Condition ◽  
Private Alleles

Fragmentation of the landscape by human activity has created small, isolated plant populations. Hakea carinata F. Muell. ex Meissner, a sclerophyllous shrub, is common in isolated fragments of vegetation in South Australia. This study investigated whether habitat fragmentation has caused restrictions to gene flow between populations. Gene diversity (HT = 0.317) is average for similar species but little is held within populations (HS = 0.168) and 46.9% of gene diversity is accounted for between populations. Estimates of gene flow are NM = 0.270 (based on FST) and NM = 0.129 (based on private alleles). Populations are substantially selfing (t = 0.111). Small isolated populations appears to be a long-term evolutionary condition in this species rather than a consequence of habitat fragmentation; however, population extinctions are occurring. Conservation will require the reservation of many populations to represent the genetic variation present in the species.

Genetic Management of Fragmented Animal and Plant Populations

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Biological Diversity ◽  
Extinction Risk ◽  
Outbreeding Depression ◽  
Genetic Rescue ◽  
Isolated Populations ◽  
Genetic Management ◽  
Plant Populations ◽  
Loss Of Genetic Diversity

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable consequences for many species. Many small isolated populations are going extinct unnecessarily. In many cases, such populations can be genetically rescued by gene flow into them from another population within the species, but this is very rarely done. This novel and authoritative book addresses the issues involved in genetic management of fragmented animal and plant populations, including inbreeding depression, loss of genetic diversity and elevated extinction risk in small isolated populations, augmentation of gene flow, genetic rescue, causes of outbreeding depression and predicting its occurrence, desirability and implementation of genetic translocations to cope with climate change, and defining and diagnosing species for conservation purposes.

scholarly journals Atlantic Forest fragmentation affects the genetic variation distribution pattern in blue manakins, Chiroxiphia caudata (Aves, Pipridae)

2018 ◽  
Author(s):  
Leonardo P. Niero ◽  
Mercival R. Francisco ◽  
Bruno H. Saranholi ◽  
Luis F. Silveira ◽  
Pedro M. Galetti Jr
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Gene Flow ◽  
Discriminant Analysis ◽  
Habitat Fragmentation ◽  
Atlantic Forest ◽  
Conservation Biology ◽  
Generalist Species ◽  
Private Alleles ◽  
Forest Biome

Habitat fragmentation is one of the main threats to the biodiversity and one of the main challenges faced by conservation biology. This study assessed the effects of habitat fragmentation on the genetic variability of the blue manakin Chiroxiphia caudata, an endemic bird of Atlantic Forest biome. Nine microsatellite loci were used to analyze individuals from five Atlantic Forest areas. Private alleles were found in all areas. Fst, Dest, Bayesian and Discriminant analysis of principal components (DAPC) indicated that populations are genetically structured, but the distance could not explain the differentiation between areas. The fragmentation and the reduction of gene flow may be acting in order to increase the differentiation between areas. Thus, even a generalist species may be affected by habitat fragmentation. Despite this, the whole complex of fragmented areas in Atlantic Forest appears to play an important role for the blue manakin by sheltering its genetic diversity as a whole.

scholarly journals Atlantic Forest fragmentation affects the genetic variation distribution pattern in blue manakins, Chiroxiphia caudata (Aves, Pipridae)

2018 ◽  
Author(s):  
Leonardo P. Niero ◽  
Mercival R. Francisco ◽  
Bruno H. Saranholi ◽  
Luis F. Silveira ◽  
Pedro M. Galetti Jr
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Gene Flow ◽  
Discriminant Analysis ◽  
Habitat Fragmentation ◽  
Atlantic Forest ◽  
Conservation Biology ◽  
Generalist Species ◽  
Private Alleles ◽  
Forest Biome

Habitat fragmentation is one of the main threats to the biodiversity and one of the main challenges faced by conservation biology. This study assessed the effects of habitat fragmentation on the genetic variability of the blue manakin Chiroxiphia caudata, an endemic bird of Atlantic Forest biome. Nine microsatellite loci were used to analyze individuals from five Atlantic Forest areas. Private alleles were found in all areas. Fst, Dest, Bayesian and Discriminant analysis of principal components (DAPC) indicated that populations are genetically structured, but the distance could not explain the differentiation between areas. The fragmentation and the reduction of gene flow may be acting in order to increase the differentiation between areas. Thus, even a generalist species may be affected by habitat fragmentation. Despite this, the whole complex of fragmented areas in Atlantic Forest appears to play an important role for the blue manakin by sheltering its genetic diversity as a whole.

A Practical Guide for Genetic Management of Fragmented Animal and Plant Populations

2019 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Human Activity ◽  
Biological Diversity ◽  
Wild Animal ◽  
Isolated Populations ◽  
Genetic Management ◽  
Plant Populations ◽  
Practical Guide ◽  
Loss Of Genetic Diversity

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of wild animal and plant populations decreases and fragmentation increases, inbreeding reduces fitness and loss of genetic diversity reduces their ability to adapt to changes in the environment. Many small isolated populations are going extinct unnecessarily. In many cases, such populations can be genetically rescued by gene flow from another population within the species, but this is very rarely done. This book provides a practical guide to the genetic management of fragmented animal and plant populations.

Long-term effects of habitat fragmentation on mating patterns and gene flow of a tropical dry forest tree, Ceiba aesculifolia (Malvaceae: Bombacoideae)

2013 ◽  
Vol 100 (6) ◽  
pp. 1095-1101 ◽  
Author(s):  
Mauricio Quesada ◽  
Yvonne Herrerías-Diego ◽  
Jorge A. Lobo ◽  
Gumersindo Sánchez-Montoya ◽  
Fernando Rosas ◽  
...  
Keyword(s):  
Gene Flow ◽  
Habitat Fragmentation ◽  
Tropical Dry Forest ◽  
Forest Tree ◽  
Dry Forest ◽  
Long Term Effects ◽  
Mating Patterns ◽  
Ceiba Aesculifolia

Anthropologic Relationships among Prehistoric Northeastern Amerindians

1980 ◽  
Vol 1 (2) ◽  
pp. 145-159
Author(s):  
Edward F. Harris ◽  
Nicholas F. Bellantoni
Keyword(s):  
New York ◽  
Gene Flow ◽  
Material Culture ◽  
New England ◽  
Cultural Barriers ◽  
Group Differences ◽  
Phenetic Analysis ◽  
Trade Relationships ◽  
Good Agreement

Archaeologically defined inter-group differences in the Northeast subarea ate assessed with a phenetic analysis of published craniometric information. Spatial distinctions in the material culture are in good agreement with those defined by the cranial metrics. The fundamental dichotomy, between the Ontario Iroquois and the eastern grouping of New York and New England, suggests a long-term dissociation between these two groups relative to their ecologic adaptations, trade relationships, trait-list associations, and natural and cultural barriers to gene flow.

Are there populations suffering genetic erosion that would benefit from augmented gene flow?

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Erosion ◽  
Genetic Rescue ◽  
Isolated Populations

Having identified small geographically and genetically isolated populations, we need to determine whether they are suffering genetic erosion, and if so, whether there are any other populations to which they could be crossed. We should next ask whether crossing is expected to be harmful or beneficial, and if beneficial, whether the benefits would be large enough to justify a genetic rescue attempt. Here, we address these questions based on the principles established in the preceding chapters.

Population fragmentation causes inadequate gene flow and increases extinction risk

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Gene Flow ◽  
Extinction Risk ◽  
Random Mating ◽  
Large Population ◽  
Isolated Population ◽  
Population Fragmentation ◽  
Single Population ◽  
Total Size ◽  
Limited Gene Flow

Most species now have fragmented distributions, often with adverse genetic consequences. The genetic impacts of population fragmentation depend critically upon gene flow among fragments and their effective sizes. Fragmentation with cessation of gene flow is highly harmful in the long term, leading to greater inbreeding, increased loss of genetic diversity, decreased likelihood of evolutionary adaptation and elevated extinction risk, when compared to a single population of the same total size. The consequences of fragmentation with limited gene flow typically lie between those for a large population with random mating and isolated population fragments with no gene flow.

scholarly journals Prediction of Genetic Contributions and Generation Intervals in Populations With Overlapping Generations Under Selection

Genetics ◽  
1999 ◽  
Vol 151 (3) ◽  
pp. 1197-1210 ◽  
Author(s):  
Piter Bijma ◽  
John A Woolliams
Keyword(s):  
Gene Flow ◽  
Overlapping Generations ◽  
Selective Advantage ◽  
Turnover Time ◽  
Breeding Value ◽  
Age Classes ◽  
Generation Interval ◽  
Young Parents ◽  
Genetic Contributions

Abstract A method to predict long-term genetic contributions of ancestors to future generations is studied in detail for a population with overlapping generations under mass or sib index selection. An existing method provides insight into the mechanisms determining the flow of genes through selected populations, and takes account of selection by modeling the long-term genetic contribution as a linear regression on breeding value. Total genetic contributions of age classes are modeled using a modified gene flow approach and long-term predictions are obtained assuming equilibrium genetic parameters. Generation interval was defined as the time in which genetic contributions sum to unity, which is equal to the turnover time of genes. Accurate predictions of long-term genetic contributions of individual animals, as well as total contributions of age classes were obtained. Due to selection, offspring of young parents had an above-average breeding value. Long-term genetic contributions of youngest age classes were therefore higher than expected from the age class distribution of parents, and generation interval was shorter than the average age of parents at birth of their offspring. Due to an increased selective advantage of offspring of young parents, generation interval decreased with increasing heritability and selection intensity. The method was compared to conventional gene flow and showed more accurate predictions of long-term genetic contributions.

scholarly journals Getting the Most From Surveys: How Method Selection and Method Modification Impact Butterfly Survey Data

2021 ◽  
Author(s):  
Katherine C Kral-O’Brien ◽  
Adrienne K Antonsen ◽  
Torre J Hovick ◽  
Ryan F Limb ◽  
Jason P Harmon
Keyword(s):  
Species Richness ◽  
New Species ◽  
Count Data ◽  
Distance Sampling ◽  
Line Transect ◽  
Similar Species ◽  
Method Selection ◽  
M 10 ◽  
Sampling Procedures

Abstract Many methods are used to survey butterfly populations, with line transect and area surveys being prominent. Observers are typically limited to search within 5 or 10 m from the line, while observers are unrestricted in larger specified search regions in area surveys. Although methods differ slightly, the selection is often based on producing defendable data for conservation, maximizing data quality, and minimizing effort. To guide method selection, we compared butterfly surveys using 1) line versus area methods and 2) varying width transects (5 m, 10 m, or unrestricted) using count data from surveys in North Dakota from 2015 to 2018. Between line and area surveys, we detected more individuals with area surveys, even when accounting for effort. However, both methods accumulated new species at similar rates. When comparing transect methodology, we detected nearly 60% more individuals and nine more species when transect width increased from 5 m to unrestricted, despite similar effort across methodology. Overall, we found line surveys slightly less efficient at detecting individuals, but they collected similar species richness to area surveys when accounting for effort. Additionally, line surveys allow the use of unrestricted-width transects with distance sampling procedures, which were more effective at detecting species and individuals while providing a means to correct count data over the same transect length. Methods that reduce effort and accurately depict communities are especially important for conservation when long-term datasets are unavailable.

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