scholarly journals Long-term effective population size dynamics of an intensively monitored vertebrate population

Heredity ◽  
2016 ◽  
Vol 117 (4) ◽  
pp. 290-299 ◽  
Author(s):  
A-K Mueller ◽  
N Chakarov ◽  
O Krüger ◽  
J I Hoffman
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Effective Population

scholarly journals Historical population size of the threatened New Zealand sea lion Phocarctos hookeri

2015 ◽  
Vol 97 (2) ◽  
pp. 436-443 ◽  
Author(s):  
Catherine J. Collins ◽  
B. Louise Chilvers ◽  
Matthew Taylor ◽  
Bruce C. Robertson
Keyword(s):  
New Zealand ◽  
Population Size ◽  
Effective Population Size ◽  
Carrying Capacity ◽  
Effective Population ◽  
Sea Lion ◽  
Sea Lions ◽  
Target Values ◽  
Phocarctos Hookeri

Abstract Marine mammal species were exploited worldwide during periods of commercial sealing in the 18th and 19th centuries. For many of these species, an estimate of the pre-exploitation abundance of the species is lacking, as historical catch records are generally scarce and inaccurate. Genetic estimates of long-term effective population size provide a means to estimate the pre-exploitation abundance. Here, we apply genetic methods to estimate the long-term effective population size of the subantarctic lineage of the New Zealand sea lion (NZ sea lion), Phocarctos hookeri . This species is predominantly restricted to the subantarctic islands, south of mainland New Zealand, following commercial sealing in the 19th century. Today, the population consists of ~9,880 animals and population growth is slow. Auckland Island breeding colonies of NZ sea lion are currently impacted by commercial trawl fisheries via regular sea lion deaths as bycatch. In order to estimate sustainable levels of bycatch, an estimate of the population’s carrying capacity ( K ) is required. We apply the genetically estimated long-term effective population size of NZ sea lions as a proxy for the estimated historical carrying capacity of the subantarctic population. The historical abundance of subantarctic NZ sea lions was significantly higher than the target values of K employed by the contemporary management. The current management strategy may allow unsustainable bycatch levels, thereby limiting the recovery of the NZ sea lion population toward historical carrying capacity.

Significance of Mature Male Parr in a Small Population of Atlantic Salmon (Salmo salar)

1989 ◽  
Vol 46 (6) ◽  
pp. 928-931 ◽  
Author(s):  
Jan Hennsng L'abée-Lund
Keyword(s):  
Atlantic Salmon ◽  
Population Size ◽  
Effective Population Size ◽  
Salmo Salar ◽  
Small Population ◽  
Mature Male ◽  
Effective Population ◽  
Atlantic Salmon Salmo Salar ◽  
Mature Male Parr

The spawning population of Atlantic salmon, Salmo salar, (mature male parr and adults (anadromous salmon)) were assessed in the River Baevra, central Norway, when the river was treated with rotenone in November 1986. The spawning population of adults consisted of 15 males and 19 females. The spawning population of males consisted of 167 mature male parr per adult male. The effective population size of adults was small; Na = 33.5 individuals. The presence of mature male parr theoretically increased the effective population size to Na = 71.7 individuals. This increase indicated that mature male parr brought the effective population size above a recommended minimum (Na = 50) to ensure long term viability.

scholarly journals On the independent loci assumption in phylogenomic studies

2016 ◽  
Author(s):  
W. Bryan Jennings
Keyword(s):  
Homologous Recombination ◽  
Population Size ◽  
Effective Population Size ◽  
Gene Tree ◽  
Gene Trees ◽  
Species Trees ◽  
Long Term Effects ◽  
Effective Population ◽  
Independent Assortment

AbstractStudies using multi-locus coalescent methods to infer species trees or historical demographic parameters usually require the assumption that the gene tree for each locus (or SNP) is genealogically independent from the gene trees of other sampled loci. In practice, however, researchers have used two different criteria to delimit independent loci in phylogenomic studies. The first criterion, which directly addresses the condition of genealogical independence of sampled loci, considers the long-term effects of homologous recombination and effective population size on linkage between two loci. In contrast, the second criterion, which only considers the single-generation effects of recombination in the meioses of individuals, identifies sampled loci as being independent of each other if they undergo Mendelian independent assortment. Methods that use these criteria to estimate the number of independent loci per genome as well as intra-chromosomal “distance thresholds” that can be used to delimit independent loci in phylogenomic datasets are reviewed. To compare the efficacy of each criterion, they are applied to two species (an invertebrate and vertebrate) for which relevant genetic and genomic data are available. Although the independent assortment criterion is relatively easy to apply, the results of this study show that it is overly conservative and therefore its use would unfairly restrict the sizes of phylogenomic datasets. It is therefore recommended that researchers only refer to genealogically independent loci when discussing the independent loci assumption in phylogenomics and avoid using terms that may conflate this assumption with independent assortment. Moreover, whenever feasible, researchers should use methods for delimiting putatively independent loci that take into account both homologous recombination and effective population size (i.e., long-term effective recombination).

Global changes explain the long-term demographic trend of the Eurasian common lizard (Squamata: Lacertidae)

2021 ◽  
Author(s):  
Jose L Horreo ◽  
Patrick S Fitze
Keyword(s):  
Growth Rate ◽  
Population Size ◽  
Effective Population Size ◽  
Climatic Changes ◽  
Vegetation Changes ◽  
Effective Population ◽  
Short Term ◽  
Demographic Trend ◽  
Common Lizard

Abstract The demographic trend of a species depends on the dynamics of its local populations, which can be compromised by local or by global phenomena. However, the relevance of local and global phenomena has rarely been investigated simultaneously. Here we tested whether local phenomena compromised a species’ demographic trend using the Eurasian common lizard Zootoca vivipara, the terrestrial reptile exhibiting the widest geographic distribution, as a model species. We analysed the species’ ancient demographic trend using genetic data from its six allopatric genetic clades and tested whether its demographic trend mainly depended on single clades or on global phenomena. Zootoca vivipara’s effective population size increased since 2.3 million years ago and started to increase steeply and continuously from 0.531 Mya. Population growth rate exhibited two maxima, both occurring during global climatic changes and important vegetation changes on the northern hemisphere. Effective population size and growth rate were negatively correlated with global surface temperatures, in line with global parameters driving long-term demographic trends. Zootoca vivipara’s ancient demography was not driven by a single clade, nor by the two clades that colonized huge geographic areas after the last glaciation. The low importance of local phenomena, suggests that the experimentally demonstrated high sensitivity of this species to short-term ecological changes is a response in order to cope with short-term and local changes. This suggests that what affected its long-term demographic trend the most, were not these local changes/responses, but rather the important and prolonged global climatic changes and important vegetation changes on the northern hemisphere, including the opening up of the forest by humans.

scholarly journals Long-term isolation at a low effective population size greatly reduced genetic diversity in Gulf of California fin whales

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Vania E. Rivera-León ◽  
Jorge Urbán ◽  
Sally Mizroch ◽  
Robert L. Brownell ◽  
Tom Oosting ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Effective Population Size ◽  
Gulf Of California ◽  
Effective Population ◽  
Fin Whales
Sign in / Sign up

Export Citation Format

Share Document