Limits...
Positive correlation between genetic diversity and fitness in a large, well-connected metapopulation.

Vandewoestijne S, Schtickzelle N, Baguette M - BMC Biol. (2008)

Bottom Line: Theory predicts that lower dispersal, and associated gene flow, leads to decreased genetic diversity in small isolated populations, which generates adverse consequences for fitness, and subsequently for demography.Our results suggest that dispersal is a very important factor maintaining genetic diversity.This result may be especially pertinent for species at their range margins, particularly in this era of rapid environmental change.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biodiversity Research Centre, Université catholique de Louvain, Place Croix du Sud 5, 1348 Louvain-la-Neuve, Belgium. sofie.vandewoestijne@uclouvain.be

ABSTRACT

Background: Theory predicts that lower dispersal, and associated gene flow, leads to decreased genetic diversity in small isolated populations, which generates adverse consequences for fitness, and subsequently for demography. Here we report for the first time this effect in a well-connected natural butterfly metapopulation with high population densities at the edge of its distribution range.

Results: We demonstrate that: (1) lower genetic diversity was coupled to a sharp decrease in adult lifetime expectancy, a key component of individual fitness; (2) genetic diversity was positively correlated to the number of dispersing individuals (indicative of landscape functional connectivity) and adult population size; (3) parameters inferred from capture-recapture procedures (population size and dispersal events between patches) correlated much better with genetic diversity than estimates usually used as surrogates for population size (patch area and descriptors of habitat quality) and dispersal (structural connectivity index).

Conclusion: Our results suggest that dispersal is a very important factor maintaining genetic diversity. Even at a very local spatial scale in a metapopulation consisting of large high-density populations interconnected by considerable dispersal rates, genetic diversity can be decreased and directly affect the fitness of individuals. From a biodiversity conservation perspective, this study clearly shows the benefits of both in-depth demographic and genetic analyses. Accordingly, to ensure the long-term survival of populations, conservation actions should not be blindly based on patch area and structural isolation. This result may be especially pertinent for species at their range margins, particularly in this era of rapid environmental change.

Show MeSH
Genetic diversity was positively correlated with lifetime expectancy (LTE). Butterflies from local populations with the highest genetic diversity had a LTE up to c. 25% higher, directly affecting their individual fitness through lifetime reproductive success. Colours refer to sites in Figure 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2587462&req=5

Figure 2: Genetic diversity was positively correlated with lifetime expectancy (LTE). Butterflies from local populations with the highest genetic diversity had a LTE up to c. 25% higher, directly affecting their individual fitness through lifetime reproductive success. Colours refer to sites in Figure 1.

Mentions: Variations between populations in genetic diversity were positively correlated to variations in LTE (Table 3; Figure 2). This correlation was highly significant for He. While not significant at the 0.05 level, Div and PPL also showed largely positive covariation with LTE. The example of the He-LTE correlation is used to show that this correlation remained largely unaltered when the uncertainties in the estimates of He and LTE were fully taken into account, and is robust to a large decrease of the number of loci on which genetic diversity was computed (Figure 3). This positive relation implies that butterflies from populations with the highest genetic diversity had a mean lifetime expectancy up to c. 25% higher than butterflies from populations characterised by a low genetic diversity.


Positive correlation between genetic diversity and fitness in a large, well-connected metapopulation.

Vandewoestijne S, Schtickzelle N, Baguette M - BMC Biol. (2008)

Genetic diversity was positively correlated with lifetime expectancy (LTE). Butterflies from local populations with the highest genetic diversity had a LTE up to c. 25% higher, directly affecting their individual fitness through lifetime reproductive success. Colours refer to sites in Figure 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2587462&req=5

Figure 2: Genetic diversity was positively correlated with lifetime expectancy (LTE). Butterflies from local populations with the highest genetic diversity had a LTE up to c. 25% higher, directly affecting their individual fitness through lifetime reproductive success. Colours refer to sites in Figure 1.
Mentions: Variations between populations in genetic diversity were positively correlated to variations in LTE (Table 3; Figure 2). This correlation was highly significant for He. While not significant at the 0.05 level, Div and PPL also showed largely positive covariation with LTE. The example of the He-LTE correlation is used to show that this correlation remained largely unaltered when the uncertainties in the estimates of He and LTE were fully taken into account, and is robust to a large decrease of the number of loci on which genetic diversity was computed (Figure 3). This positive relation implies that butterflies from populations with the highest genetic diversity had a mean lifetime expectancy up to c. 25% higher than butterflies from populations characterised by a low genetic diversity.

Bottom Line: Theory predicts that lower dispersal, and associated gene flow, leads to decreased genetic diversity in small isolated populations, which generates adverse consequences for fitness, and subsequently for demography.Our results suggest that dispersal is a very important factor maintaining genetic diversity.This result may be especially pertinent for species at their range margins, particularly in this era of rapid environmental change.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biodiversity Research Centre, Université catholique de Louvain, Place Croix du Sud 5, 1348 Louvain-la-Neuve, Belgium. sofie.vandewoestijne@uclouvain.be

ABSTRACT

Background: Theory predicts that lower dispersal, and associated gene flow, leads to decreased genetic diversity in small isolated populations, which generates adverse consequences for fitness, and subsequently for demography. Here we report for the first time this effect in a well-connected natural butterfly metapopulation with high population densities at the edge of its distribution range.

Results: We demonstrate that: (1) lower genetic diversity was coupled to a sharp decrease in adult lifetime expectancy, a key component of individual fitness; (2) genetic diversity was positively correlated to the number of dispersing individuals (indicative of landscape functional connectivity) and adult population size; (3) parameters inferred from capture-recapture procedures (population size and dispersal events between patches) correlated much better with genetic diversity than estimates usually used as surrogates for population size (patch area and descriptors of habitat quality) and dispersal (structural connectivity index).

Conclusion: Our results suggest that dispersal is a very important factor maintaining genetic diversity. Even at a very local spatial scale in a metapopulation consisting of large high-density populations interconnected by considerable dispersal rates, genetic diversity can be decreased and directly affect the fitness of individuals. From a biodiversity conservation perspective, this study clearly shows the benefits of both in-depth demographic and genetic analyses. Accordingly, to ensure the long-term survival of populations, conservation actions should not be blindly based on patch area and structural isolation. This result may be especially pertinent for species at their range margins, particularly in this era of rapid environmental change.

Show MeSH