scholarly journals Life history and environmental variation interact to determine effective population to census size ratio

2006 ◽  
Vol 273 (1605) ◽  
pp. 3065-3073 ◽  
Author(s):  
Thomas F Turner ◽  
Megan J Osborne ◽  
Gregory R Moyer ◽  
Melissa A Benavides ◽  
Dominique Alò
Keyword(s):  
Genetic Diversity ◽  
Life History ◽  
Fish Species ◽  
Life Histories ◽  
Effective Population ◽  
High Fecundity ◽  
Type Iii ◽  
Census Size ◽  
Bony Fishes ◽  
Successful Recovery

Successful recovery and sustainability of threatened and exploited species depends in part on retention and maintenance of genetic diversity. Theory indicates that genetic diversity is lost at a rate inversely proportional to the genetically effective population size ( N e ), which is roughly equal to one-half the adult census size ( N ) in many organisms. However, N e has been reported to be up to five orders of magnitude lower than N in species with life histories that result in type III survivorship (high fecundity, but heavy mortality in early life stages, e.g. bony fishes), prompting speculation that low values of N e may be a general feature of such organisms despite sometimes vast abundances. Here, we compared N e and the ratio N e / N across three ecologically similar fish species from the arid southwestern United States, all with type III life histories but with differing expectations of egg and larval survivorship that correlate with the degree of human-imposed habitat fragmentation. Our study indicates that type III life history may be necessary, but this alone is insufficient to account for extraordinarily low values of N e / N . Rather, life history interacts with environmentally imposed mortality to determine the rate and magnitude of change in genetic diversity in these desert fish species.

scholarly journals Patterns of Life-History Diversification in North American Fishes: implications for Population Regulation

1992 ◽  
Vol 49 (10) ◽  
pp. 2196-2218 ◽  
Author(s):  
Kirk O. Winemiller ◽  
Kenneth A. Rose
Keyword(s):  
Life History ◽  
Parental Care ◽  
North American ◽  
Life Histories ◽  
Egg Size ◽  
Life History Strategies ◽  
Large Species ◽  
High Fecundity ◽  
Adult Growth ◽  
Trade Offs

Interspecific patterns of fish life histories were evaluated in relation to several theoretical models of life-history evolution. Data were gathered for 216 North American fish species (57 families) to explore relationships among variables and to ordinate species. Multivariate tests, performed on freshwater, marine, and combined data matrices, repeatedly identified a gradient associating later-maturing fishes with higher fecundity, small eggs, and few bouts of reproduction during a short spawning season and the opposite suite of traits with small fishes. A second strong gradient indicated positive associations between parental care, egg size, and extended breeding seasons. Phylogeny affected each variable, and some higher taxonomic groupings were associated with particular life-history strategies. High-fecundity characteristics tended to be associated with large species ranges in the marine environment. Age at maturation, adult growth rate, life span, and egg size positively correlated with anadromy. Parental care was inversely correlated with median latitude. A trilateral continuum based on essential trade-offs among three demographic variables predicts many of the correlations among life-history traits. This framework has implications for predicting population responses to diverse natural and anthropogenic disturbances and provides a basis for comparing responses of different species to the same disturbance.

scholarly journals Life histories predict genetic diversity and population structure within three species of Octopus targeted by small-scale fisheries in Northwest Mexico

2017 ◽  
Author(s):  
José F Domínguez-Contreras ◽  
Adrian Munguia-Vega ◽  
Bertha P Ceballos-Vázquez ◽  
Marcial Arellano-Martínez ◽  
Francisco J García-Rodríguez ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Population Size ◽  
Effective Population Size ◽  
Gulf Of California ◽  
Life Histories ◽  
Local Population ◽  
Small Scale ◽  
Effective Population ◽  
Northwest Mexico

The fishery for octopus in Northwest Mexico has increased to over 2,000 tons annually, but to date the specific composition of the catch has been ignored. With at least three main species with varying life histories targeted by artisanal fisheries in the region, lack of information about the distribution of each species and metapopulation size and structure could impede effective fisheries management to avoid overexploitation. Here we tested if different life histories in three species of octopus help to predict observed patterns of genetic diversity, population dynamics, structure and connectivity that could be relevant to the sustainable management of the fishery. We sequenced two mitochondrial genes and genotyped seven nuclear microsatellite loci to identify the distribution of each species in 20 locations from the Gulf of California and the Pacific coast of the Baja California peninsula. We tested four a priori hypothesis derived from population genetic theory based on differences in the fecundity and dispersal potential for each species. We found that the species with low fecundity and without a planktonic larval stage (Octopus bimaculoides) had lower average effective population size and genetic diversity, but higher levels of kinship, population structure, and richness of private alleles, suggesting limited dispersal and high local recruitment. In contrast, two species with higher fecundity and planktonic larvae (O. bimaculatus, O. hubbsorum) showed higher effective population size and genetic diversity, and overall lower kinship and population structure, supporting higher levels of gene flow over a larger geographical scale. Even among the latter, there were differences in the calculated parameters possibly associated with increased connectivity in the species with the longest planktonic larval duration (O. bimaculatus). We consider that O. bimaculoides could be more susceptible to over exploitation of small, isolated populations that could have longer recovery times, and suggest that management should take place within each local population. For the two species with pelagic larvae, management should consider metapopulation structure over larger geographic scales and the directionality and magnitude of larval dispersal between localities driven by ocean currents. The distribution of each species and variations in their reproductive timing should also be considered when establishing marine reserves or seasonal fishing closures.

scholarly journals Recent demographic histories and genetic diversity across pinnipeds are shaped by anthropogenic interactions and mediated by ecology and life-history

2018 ◽  
Author(s):  
M.A. Stoffel ◽  
E. Humble ◽  
K. Acevedo-Whitehouse ◽  
B.L. Chilvers ◽  
B. Dickerson ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Life History ◽  
Large Scale ◽  
Biodiversity Loss ◽  
Single Species ◽  
Population Viability ◽  
Breeding Habitat ◽  
Comparative Approach ◽  
Population Declines ◽  
Effective Population

AbstractA central paradigm in conservation biology is that population bottlenecks reduce genetic diversity and negatively impact population viability and adaptive potential. In an era of unprecedented biodiversity loss and climate change, understanding both the determinants and consequences of bottlenecks in wild populations is therefore an increasingly important challenge. However, as most studies have focused on single species, the multitude of potential drivers and the consequences of bottlenecks remain elusive. Here, we used a comparative approach by integrating genetic data from over 11,000 individuals of 30 pinniped species with demographic, ecological and life history data to elucidate the consequences of large-scale commercial exploitation by 18th and 19th century sealers. We show that around one third of these species exhibit strong genetic signatures of recent population declines, with estimated bottleneck effective population sizes reflecting just a few tens of surviving individuals in the most extreme cases. Bottleneck strength was strongly associated with both breeding habitat and mating system variation, and together with global abundance explained a large proportion of the variation in genetic diversity across species. Overall, there was no relationship between bottleneck intensity and IUCN status, although three of the four most heavily bottlenecked species are currently endangered. Our study reveals an unforeseen interplay between anthropogenic exploitation, ecology, life history and demographic declines, sheds new light on the determinants of genetic diversity, and is consistent with the notion that both genetic and demographic factors influence population viability.

The persistence niche: what makes it and what breaks it for two fire-prone plant species

2007 ◽  
Vol 55 (3) ◽  
pp. 273 ◽  
Author(s):  
David A. Keith ◽  
Mark G. Tozer ◽  
Tracey J. Regan ◽  
Helen M. Regan
Keyword(s):  
Life History ◽  
Seed Production ◽  
Life Histories ◽  
Phytophthora Cinnamomi ◽  
Population Viability ◽  
Vital Rates ◽  
High Fecundity ◽  
In Fire ◽  
Rates Of Growth ◽  
Regeneration Niches

Persistence niches are expected to favour qualitatively different plant life histories compared with regeneration niches. In fire-prone habitats, for example, resprouting plants may be expected to exploit persistence niches, whereas obligate-seeders by definition exploit regeneration niches. Resprouter life histories should be typified by high rates of survival, which may be offset by relatively low rates of growth and reproduction. This combination of characters is expected to result from trade-offs in resource allocation and because the longevity of individual plants should buffer their populations against the effects of recruitment failure. We asked whether two resprouting perennial shrubs, Epacris barbata Melville and Xanthorrhoea resinifera (Sol. Ex Kite) E.C.Nelson & D.J.Bedford, exhibited the life-history character combinations that are expected for species exploiting a persistence niche. We also investigated how a change in habitat suitability caused by the invasion of a root pathogen may limit the ability of these species to occupy persistence niches. Demographic censuses of several years’ duration in two populations of each species yielded estimates of vital rates that were consistent with the life-history profile expected for a persistence niche. Rates of background survival were high and rates of fire-related mortality were low in both species. As expected, these were associated with low rates of growth and seedling establishment, although rates of seed production and viability were relatively high in both species. The importance of survival was confirmed by stochastic population models, which showed that population viability was more sensitive to decreases in survival of mature plants and increases in fire mortality of established plants than to changes in other vital rates. Seedling growth rates were also relatively important in E. barbata. Populations of both species that had been infected by root rot disease, Phytophthora cinnamomi, had substantially reduced survival rates and, consequently, reduced population viability. These effects were more extreme in E. barbata than in X. resinifera. We conclude that processes that reduce survival, such as disease infection and habitat loss, rather than processes that impede seed production and recruitment mediate the persistence niche. However, we discuss the possibility that this dependency might be mitigated by high fecundity if infrequent conditions that permit large recruitment events have so far eluded detection.

The effect of a supplementation program on the genetic and life history characteristics of an Oncorhynchus mykiss population

2010 ◽  
Vol 67 (9) ◽  
pp. 1449-1458 ◽  
Author(s):  
Donald M. Van Doornik ◽  
Barry A. Berejikian ◽  
Lance A. Campbell ◽  
Eric C. Volk
Keyword(s):  
Genetic Diversity ◽  
Life History ◽  
Oncorhynchus Mykiss ◽  
Population Size ◽  
Effective Population Size ◽  
Natural Environment ◽  
Natural Populations ◽  
Life History Trait ◽  
Effective Population ◽  
Important Life History Trait

Conservation hatcheries, which supplement natural populations by removing adults or embryos from the natural environment and rearing and releasing parr, smolts, or adults back into their natal or ancestral streams, are increasingly being used to avoid extinction of localized populations of Pacific salmonids. We collected data before and during a steelhead ( Oncorhynchus mykiss ) supplementation program to investigate the effect that the program has had on the population’s genetic diversity and effective population size and any changes to an important life history trait (residency or anadromy). We found that supplementation did not cause substantial changes in the genetic diversity or effective size of the population, most likely because a large proportion of all of the steelhead redds in the river each year were sampled to create the supplementation broodstock. Our data also showed that the captively reared fish released as adults successfully produced parr. Furthermore, we found that during supplementation, there was an increase in the proportion of O. mykiss with anadromous ancestry vs. resident ancestry.

Life history strategies, population regulation, and implications for fisheries management

2005 ◽  
Vol 62 (4) ◽  
pp. 872-885 ◽  
Author(s):  
Kirk O Winemiller
Keyword(s):  
Life History ◽  
Life Histories ◽  
A Priori ◽  
Species Conservation ◽  
Life History Strategies ◽  
High Fecundity ◽  
Density Dependent ◽  
Compensatory Reserve ◽  
Management And Development ◽  
High Reproductive Effort

Life history theories attempt to explain the evolution of organism traits as adaptations to environmental variation. A model involving three primary life history strategies (endpoints on a triangular surface) describes general patterns of variation more comprehensively than schemes that examine single traits or merely contrast fast versus slow life histories. It provides a general means to predict a priori the types of populations with high or low demographic resilience, production potential, and conformity to density-dependent regulation. Periodic (long-lived, high fecundity, high recruitment variation) and opportunistic (small, short-lived, high reproductive effort, high demographic resilience) strategies should conform poorly to models that assume density-dependent recruitment. Periodic-type species reveal greatest recruitment variation and compensatory reserve, but with poor conformity to stock–recruitment models. Equilibrium-type populations (low fecundity, large egg size, parental care) should conform better to assumptions of density-dependent recruitment, but have lower demographic resilience. The model's predictions are explored relative to sustainable harvest, endangered species conservation, supplemental stocking, and transferability of ecological indices. When detailed information is lacking, species ordination according to the triangular model provides qualitative guidance for management and development of more detailed predictive models.

scholarly journals Simple life-history traits explain key effective population size ratios across diverse taxa

2013 ◽  
Vol 280 (1768) ◽  
pp. 20131339 ◽  
Author(s):  
Robin S. Waples ◽  
Gordon Luikart ◽  
James R. Faulkner ◽  
David A. Tallmon
Keyword(s):  
Life History ◽  
Population Size ◽  
Effective Population Size ◽  
Life History Traits ◽  
Vital Rates ◽  
Effective Population ◽  
Adult Lifespan ◽  
Census Size ◽  
The Rich ◽  
And Migration

Effective population size ( N e ) controls both the rate of random genetic drift and the effectiveness of selection and migration, but it is difficult to estimate in nature. In particular, for species with overlapping generations, it is easier to estimate the effective number of breeders in one reproductive cycle ( N b ) than N e per generation. We empirically evaluated the relationship between life history and ratios of N e , N b and adult census size ( N ) using a recently developed model ( agene ) and published vital rates for 63 iteroparous animals and plants. N b / N e varied a surprising sixfold across species and, contrary to expectations, N b was larger than N e in over half the species. Up to two-thirds of the variance in N b / N e and up to half the variance in N e / N was explained by just two life-history traits (age at maturity and adult lifespan) that have long interested both ecologists and evolutionary biologists. These results provide novel insights into, and demonstrate a close general linkage between, demographic and evolutionary processes across diverse taxa. For the first time, our results also make it possible to interpret rapidly accumulating estimates of N b in the context of the rich body of evolutionary theory based on N e per generation.

scholarly journals Endemic and widespread coral reef fishes have similar mitochondrial genetic diversity

2014 ◽  
Vol 281 (1797) ◽  
pp. 20141068 ◽  
Author(s):  
Erwan Delrieu-Trottin ◽  
Jeffrey Maynard ◽  
Serge Planes
Keyword(s):  
Genetic Diversity ◽  
Coral Reef ◽  
Reef Fish ◽  
Fish Species ◽  
Nucleotide Diversity ◽  
Reef Fishes ◽  
Effective Population ◽  
Terrestrial Environment ◽  
Widespread Species ◽  
Reef Fish Species

Endemic species are frequently assumed to have lower genetic diversity than species with large distributions, even if closely related. This assumption is based on research from the terrestrial environment and theoretical evolutionary modelling. We test this assumption in the marine environment by analysing the mitochondrial genetic diversity of 33 coral reef fish species from five families sampled from Pacific Ocean archipelagos. Surprisingly, haplotype and nucleotide diversity did not differ significantly between endemic and widespread species. The probable explanation is that the effective population size of some widespread fishes locally is similar to that of many of the endemics. Connectivity across parts of the distribution of the widespread species is probably low, so widespread species can operate like endemics at the extreme or isolated parts of their range. Mitochondrial genetic diversity of many endemic reef fish species may not either limit range size or be a source of vulnerability.

scholarly journals Life histories predict genetic diversity and population structure within three species of octopus targeted by small-scale fisheries in Northwest Mexico

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4295 ◽  
Author(s):  
José F. Domínguez-Contreras ◽  
Adrian Munguia-Vega ◽  
Bertha P. Ceballos-Vázquez ◽  
Marcial Arellano-Martínez ◽  
Francisco J. García-Rodríguez ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Population Size ◽  
Life Histories ◽  
Fishery Management ◽  
The Other ◽  
Effective Population ◽  
Northwest Mexico ◽  
Dispersal Potential ◽  
Planktonic Phase

The fishery for octopus in Northwest Mexico has increased to over 2,000 tons annually, but to date the specific composition of the catch has been ignored. With at least three main species targeted by artisanal fisheries in the region with distinct life histories, the lack of basic biological information about the distribution, metapopulation size and structure of each species could impede effective fisheries management to avoid overexploitation. We tested if different life histories of three species of octopus could help predict observed patterns of genetic diversity, population dynamics, structure and connectivity and how this information could be relevant to the sustainable management of the fishery. We sequenced two mitochondrial genes and genotyped seven nuclear microsatellite loci to identify the distribution of each species in 20 locations from the Gulf of California and the west coast of the Baja California peninsula. We tested five hypotheses derived from population genetic theory based on differences in the fecundity and dispersal potential for each species. We discovered that Octopus bimaculoides with low fecundity and direct development (without a planktonic phase) had lower average effective population size and genetic diversity, but higher levels of kinship, population structure, and richness of private alleles, than the other two species. These features indicated limited dispersal and high local recruitment. In contrast, O. bimaculatus and O. hubbsorum with higher fecundity and planktonic phase as paralarvae had higher effective population size and genetic diversity, and overall lower kinship and population structure than O. bimaculoides. These observations supported higher levels of gene flow over a larger geographical scale. O. bimaculatus with the longest planktonic paralarval duration and therefore larger dispersal potential had differences in the calculated parameters possibly associated with increased connectivity. We propose O. bimaculoides is more susceptible to over exploitation of small, isolated populations and could have longer recovery times than the other two species. This species may benefit from distinct fishery management within each local population. O. bimaculatus and O. hubbsorum may benefit from fishery management that takes into account metapopulation structure over larger geographic scales and the directionality and magnitude of larval dispersal driven by ocean currents and population connectivity among individuals of each locality. The distribution of each species and variations in their reproductive phenology is also important to consider when establishing marine reserves or seasonal fishing closures.

The ongoing invasion of translocated sleepy cod (Oxyeleotris lineolata) in the Lake Eyre Basin, central Australia

2018 ◽  
Vol 45 (2) ◽  
pp. 164
Author(s):  
David Sternberg ◽  
Bernie Cockayne
Keyword(s):  
Life History ◽  
Fish Species ◽  
Fish Assemblages ◽  
Length Distribution ◽  
Fish Fauna ◽  
Native Fish ◽  
High Fecundity ◽  
Fish Samples ◽  
History Information ◽  
Central Australia

Context Present-day distribution records show that Oxyeleotris lineolata (sleepy cod) has colonised many ephemeral streams and refugial waterholes of the Cooper Creek catchment in the Lake Eyre Basin within a decade of the first record or capture. When introduced to new habitats outside its natural range, this species is considered to be a serious conservation risk to native fish species. Aims The present study aims to document the transport, establishment, colonisation and integration of O. lineolata in the Lake Eyre Basin, and quantify its impact on native fish assemblages. Methods Fish samples were taken annually in 21 waterholes between 2011 and 2016, by using a combination of single- and double-winged fyke nets. We collected novel diet and life-history information from 242 O. lineolata individuals across their known distribution. Key results Abundance, length distribution and life-history information suggested a ‘colonising front’ moving downstream, across state jurisdictional boundaries and into the Coongie Lakes Ramsar site. Oxyeleotris lineolata diet is most similar to that of two native generalist invertivore–piscivores and preys on several native fish species. With a derived longevity in excess of 15 years and a life-history strategy that combines batch spawning, high fecundity and parental care (i.e. high juvenile survivorship), there is real potential for O. lineolata to dominate fish assemblages in waterholes that provide refuge for native fishes during dry periods. Conclusions The present study showed that O. lineolata has the potential to negatively influence native fish assemblages through both competition and predation in refugial waterholes. Eradication of O. lineolata from the Cooper Creek catchment in central Australia is highly unlikely, given its widespread distribution, the remoteness of the receiving landscape and a current lack of resources to monitor spread and attempt eradication at the moving front of the Cooper Creek population. Implications Achieving greater awareness of the potential impacts of introducing or spreading non-native species is an important first step towards preserving the native fish fauna of the Lake Eyre Basin. Further research is warranted to fully understand the current and potential future distribution of O. lineolata in the basin, its biological and ecological requirements, and influence on native fish species and assemblages.

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