Effective number of breeding adults in <i>Bufo bufo</i> estimated from age‐specific variation at minisatellite loci

Scribner, Kim T.; Arntzen, J. W.; Burke, Terry

doi:10.1046/j.1365-294x.1997.00238.x

Cited by 76 publications

(94 citation statements)

References 54 publications

(36 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We estimated relatively low effective population sizes (N e ) in all of our breeding ponds, ranging from N e = 11 to 64. These estimates are similar to estimates of N e in other salamanders (Funk et al 1999;Jehle and Arntzen 2002;Savage et al 2010) and other amphibians (Scribner et al 1997;Driscoll 1999;Rowe and Beebee 2004;Wang 2009), all of which describe effective population sizes well below 100 individuals per population and often as small as N e = 10-20. Additionally, a recent review of estimates of N e across animal systems has indicated that effective population sizes in wild animal populations are generally smaller than previously thought (Frankham 2009).…”

Section: Discussionsupporting

confidence: 82%

“…Effective population sizes (N e ) in wild animal systems vary widely (Scribner et al 1997;Crawford 2003;Hoffman et al 2004;Palstra and Rruzzante 2008) and determining N e for threatened and endangered species is a key component of their conservation and management (Andersen et al 2004;Rowe and Beebee 2004;Beebee 2005;Schwartz et al 2007). Reduced effective population sizes can lead to deleterious effects, including inbreeding depression and loss of genetic diversity, which can diminish the ability of a species or population to adapt to environmental change and to respond to risks from diseases and pathogens (Crnokrak and Roff 1999;Nieminen et al 2001;Keller et al 2002;Frankham 2005).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effective population size is strongly correlated with breeding pond size in the endangered California tiger salamander, Ambystoma californiense

Wang

Johnson

et al. 2011

Conserv Genet

View full text Add to dashboard Cite

Maintaining genetic diversity and population viability in endangered and threatened species is a primary concern of conservation biology. Genetic diversity depends on population connectivity and effective population size (N e ), both of which are often compromised in endangered taxa. While the importance of population connectivity and gene flow has been well studied, investigating effective population sizes in natural systems has received far less attention. However, N e plays a prominent role in the maintenance of genetic diversity, the prevention of inbreeding depression, and in determining the probability of population persistence. In this study, we examined the relationship between breeding pond characteristics and N e in the endangered California tiger salamander, Ambystoma californiense. We sampled 203 individuals from 10 breeding ponds on a local landscape, and used 11 polymorphic microsatellite loci to quantify genetic structure, gene flow, and effective population sizes. We also measured the areas of each pond using satellite imagery and classified ponds as either hydrologically-modified perennial ponds or naturally occurring vernal pools, the latter of which constitute the natural breeding habitat for A. californiense. We found no correlation between pond area and heterozygosity or allelic diversity, but we identified a strong positive relationship between breeding pond area and N e , particularly for vernal pools. Our results provide some of the first empirical evidence that variation in breeding habitat can be associated with differences in N e and suggest that a more complete understanding of the environmental features that influence N e is an important component of conservation genetics and management.

show abstract

Section: Discussionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Effective population size is strongly correlated with breeding pond size in the endangered California tiger salamander, Ambystoma californiense

Wang

Johnson

et al. 2011

Conserv Genet

View full text Add to dashboard Cite

show abstract

“…On the assumption that all islands started out with the same initial allele frequencies, Easteal estimated N e from current F ST and the number of generations that had passed since colonization, and found the ratio of effective to census sizes, N e /N c ഠ 0.001. This estimate is very low (Nunney 1992(Nunney , 1996, but is similar to a single-season estimate of N b /N c for toad populations in Europe (Scribner et al 1997). We do not know if these variable estimates represent a fundamental difference between bufonid toads and ranid frogs.…”

supporting

confidence: 82%

Effective Population Sizes and Temporal Stability of Genetic Structure in Rana Pipiens, the Northern Leopard Frog

2004

View full text Add to dashboard Cite

Abstract. Although studies of population genetic structure are very common, whether genetic structure is stable over time has been assessed for very few taxa. The question of stability over time is particularly interesting for frogs because it is not clear to what extent frogs exist in dynamic metapopulations with frequent extinction and recolonization, or in stable patches at equilibrium between drift and gene flow. In this study we collected tissue samples from the same five populations of leopard frogs, Rana pipiens, over a 22-30 year time interval (11-15 generations). Genetic structure among the populations was very stable, suggesting that these populations were not undergoing frequent extinction and colonization. We also estimated the effective size of each population from the change in allele frequencies over time. There exist few estimates of effective size for frog populations, but the data available suggest that ranid frogs may have much larger ratios of effective size (N e ) to census size (N c ) than toads (bufonidae). Our results indicate that R. pipiens populations have effective sizes on the order of hundreds to at most a few thousand frogs, and N e /N c ratios in the range of 0.1-1.0. These estimates of N e /N c are consistent with those estimated for other Rana species. Finally, we compared the results of three temporal methods for estimating N e . Moment and pseudolikelihood methods that assume a closed population gave the most similar point estimates, although the moment estimates were consistently two to four times larger. Wang and Whitlock's new method that jointly estimates N e and the rate of immigration into a population (m) gave much smaller estimates of N e and implausibly large estimates of m. This method requires knowing allele frequencies in the source of immigrants, but was thought to be insensitive to inexact estimates. In our case the method may have failed because we did not know the true source of immigrants for each population. The method may be more sensitive to choice of source frequencies than was previously appreciated, and so should be used with caution if the most likely source of immigrants cannot be identified clearly.Key words. Anuran, genetic structure, microsatellite, Rana pipiens, temporal stability, temporal variation, variance effective size. A fundamental goal of population genetics is to understand the relative importance of microevolutionary forces in determining the existing patterns of genetic variation within a species. Consequently, using molecular markers to estimate parameters such as the effective sizes of, and migration rates among, natural populations has become a major focus in the field of evolutionary biology. However, elucidation of past processes and the prediction of future patterns from molecular data requires that a state of equilibrium have developed between genetic drift and gene flow in the populations of interest. Demographic instability can disrupt that equilibrium (Whitlock 1992), rendering single ''snapshot'' estimates of population struc...

show abstract

“…However, there could be consistent differences in N e :N c ratios between frog and toad populations. B. bufo has a very low N e :N c ratio (p0.01) based on genetic estimates that took account of variances in sex ratio and reproductive success, but not long-term fluctuations in population size over multiple generations (Scribner et al, 1997). Although no comparable studies have been reported for frogs, R. temporaria has a similar reproductive biology and seems unlikely to differ greatly from B. bufo in this respect.…”

Section: Discussionmentioning

confidence: 97%

Contrasting population structures in two sympatric anurans: implications for species conservation

Brede

Beebee

2003

Heredity

View full text Add to dashboard Cite

A general prediction of the neutral theory of evolution is that genetic diversity should correlate positively with effective population size. We show here that diversity across eight microsatellite loci was consistently and substantially lower in one common amphibian (Bufo bufo) than in another with similar life history traits (Rana temporaria) despite B. bufo having the larger breeding assemblage sizes. However, B. bufo breeding assemblages were much more highly differentiated than those of R. temporaria according to both F st and R st estimators. These differences occurred in shared habitats across identical geographical distances. The patterns of genetic diversity and differentiation detected in these two species were probably a consequence of high gene flow in R. temporaria but much lower gene flow among the larger but more dispersed B. bufo assemblages. These observations highlight the difficulty of defining the boundaries of wild populations, and show how two broadly similar species can exhibit very different population dynamics.

show abstract

Effective number of breeding adults in Bufo bufo estimated from age‐specific variation at minisatellite loci

Cited by 76 publications

References 54 publications

Effective population size is strongly correlated with breeding pond size in the endangered California tiger salamander, Ambystoma californiense

Effective population size is strongly correlated with breeding pond size in the endangered California tiger salamander, Ambystoma californiense

Effective Population Sizes and Temporal Stability of Genetic Structure in Rana Pipiens, the Northern Leopard Frog

Contrasting population structures in two sympatric anurans: implications for species conservation

Contact Info

Product

Resources

About