Effects of fragmentation on genetic diversity in island populations of the Aegean wall lizard Podarcis erhardii (Lacertidae, Reptilia)

Hurston, Heather; Voith, L.; Bonanno, Joseph A.; Foufopoulos, Johannes; Pafilis, Panayiotis; Valakos, Efstratios D.; Anthony, Nicola M.

doi:10.1016/j.ympev.2009.03.028

Cited by 46 publications

(79 citation statements)

References 75 publications

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“…When populations become fragmented in small demes and migration between them decreases or is eliminated, there is a consequent increase in inbreeding and loss of genetic diversity (Lande 1995;Frankham et al 1999;Hurston et al 2009). This scenario, together with environmental and demographic stochasticity, may have serious negative effects on the long term viability of local populations, and by extension, on the metapopulation as a whole (Keller et al 1994;Lacy 1997;Bjilsma et al 2000;Sherwin and Moritz 2000;Coulon et al 2004).…”

Section: Introductionmentioning

confidence: 99%

“…However, recent advances in molecular ecology and landscape genetics promise to improve our understanding of dispersal and gene flow in natural populations. These approaches allow us to get a better understanding of the real limits of populations and enable us to identify how different landscape elements interact with individual behavior to determine gene flow patterns and population structure (Vaha et al 2007;Dionne et al 2008;Kittlein and Gaggiotti 2008;Lada et al 2008;Leclerc et al 2008;Hurston et al 2009). …”

Section: Introductionmentioning

confidence: 99%

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Population structure and landscape genetics in the endangered subterranean rodent Ctenomys porteousi

et al. 2011

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In order to devise adequate conservation and management strategies for endangered species, it is important to incorporate a reliable understanding of its spatial population structure, detecting the existence of demographic partitions throughout its geographical range and characterizing the distribution of its genetic diversity. Moreover, in species that occupy fragmented habitats it is essential to know how landscape characteristics may affect the genetic connectivity among populations. In this study we use eight microsatellite markers to analyze population structure and gene flow patterns in the complete geographic range of the endangered rodent Ctenomys porteousi. Also, we use landscape genetics approaches to evaluate the effects of landscape configuration on the genetic connectivity among populations. In spite of geographical proximity of the sampling sites (8-27 km between the nearest sites) and the absence of marked barriers to individual movement, strong population structure and low values of gene flow were observed. Genetic differentiation among sampling sites was consistent with a simple model of isolation by distance, where peripheral areas showed higher population differentiation than those sites located in the central area of the species' distribution. Landscape genetics analysis suggested that habitat fragmentation at regional level has affected the distribution of genetic variation among populations. The distance of sampling sites to areas of the landscape having higher habitat connectivity was the environmental factor most strongly related to population genetic structure. In general, our results indicate strong genetic structure in C. porteousi, even at a small spatial scale, and suggest that habitat fragmentation could increase the population differentiation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Population structure and landscape genetics in the endangered subterranean rodent Ctenomys porteousi

et al. 2011

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“…(N A = 4.5-21.2; H E = 0.51-0.90; Nichols and Freeman 2004) and Aegean wall lizard Podarcis erhardii (N A = 1.4-12.6; H E = 0.15-0.77; Hurston et al 2009). The reduction in genetic variation within island populations, compared to their mainland counterparts, has been illustrated by numerous authors (for a review, see Frankham 1997).…”

Section: Genetic Variation Within Island Populationsmentioning

confidence: 99%

“…Although this may reflect their isolation history (e.g. a longer time since isolation than other islands, or consecutive periods of isolation; Liggins et al 2008;Hurston et al 2009), it is more likely that this may be a function of small sample sizes (n = 2 and n = 4, respectively). This observation highlights the importance of sample size in obtaining estimates of genetic variation within populations, and therefore its influence on conclusions for conservation management based on estimates from small samples.…”

Section: Genetic Variation Within Island Populationsmentioning

confidence: 99%

“…Previous research on a number of arid zone Ctenotus show that individuals have distinct home ranges, the area of which varies greatly between species, location, habitat type, season and resource availability (Pianka 1986;Read 1998). Additional studies that have examined the genetic distribution of lizards across continentalisland systems suggest that movement between islands is limited, and genetic variation is primarily determined by genetic drift (Jordan and Snell 2008;Hurston et al 2009;Miller et al 2009). Direct and anecdotal evidence suggests that lizards move between islands on their own (Schoener and Schoener 1984;Southwood and Avens 2010), or passively on rafts or other floating material (Censky et al 1998).…”

Section: Introductionmentioning

confidence: 99%

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Island size and remoteness have major conservation significance for how spatial diversity is partitioned in skinks

et al. 2015

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Islands are often acknowledged as a refuge for species with declining mainland distributions. However, as the finite size of islands coupled with isolation can lead to genetic deterioration within insular populations, the study of these systems is of great interest to the conservation of biological diversity and persistence. The remote Kimberley region in Western Australia is facing increased impacts from invasive species, habitat fragmentation, grazing, mining and altered fire regimes, and many of the 2633 islands in the Kimberley have come into focus as a significant conservation resource. The Barshouldered skink (Ctenotus inornatus) is a habitat generalist that is highly abundant throughout the Kimberley and its diverse islands. This study encompasses 41 islands and seven mainland populations in the vast Kimberley environment, and genetically characterises them using 18 nuclear (microsatellite) markers. The island populations lost heterozygosity at a rate of 1 % per kilometre from the mainland. Diversity was significantly lower on islands of small size (\500 ha) and greater than 2 km from the coastline. The scope of this study is unparalleled and addresses an important gap in our understanding of the genetic diversity throughout ecosystems. The findings illustrate how populations, operating within these pristine island systems, conform to the general rule of decreased genetic diversity with decreasing island area and increased distance from the mainland and identifies islands that may hold the most potential for conserving biodiversity.

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The effects of historical fragmentation on major histocompatibility complex class II β and microsatellite variation in the Aegean island reptile, Podarcis erhardii

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Oosterhout

et al. 2017

Ecology and Evolution

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The major histocompatibility complex (MHC) plays a key role in disease resistance and is the most polymorphic gene region in vertebrates. Although habitat fragmentation is predicted to lead to a loss in MHC variation through drift, the impact of other evolutionary forces may counter this effect. Here we assess the impact of selection, drift, migration, and recombination on MHC class II and microsatellite variability in 14 island populations of the Aegean wall lizard Podarcis erhardii. Lizards were sampled from islands within the Cyclades (Greece) formed by rising sea levels as the last glacial maximum approximately 20,000 before present. Bathymetric data were used to determine the area and age of each island, allowing us to infer the corresponding magnitude and timing of genetic bottlenecks associated with island formation. Both MHC and microsatellite variation were positively associated with island area, supporting the hypothesis that drift governs neutral and adaptive variation in this system. However, MHC but not microsatellite variability declined significantly with island age. This discrepancy is likely due to the fact that microsatellites attain mutation‐drift equilibrium more rapidly than MHC. Although we detected signals of balancing selection, recombination and migration, the effects of these evolutionary processes appeared negligible relative to drift. This study demonstrates how land bridge islands can provide novel insights into the impact of historical fragmentation on genetic diversity as well as help disentangle the effects of different evolutionary forces on neutral and adaptive diversity.

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Effects of fragmentation on genetic diversity in island populations of the Aegean wall lizard Podarcis erhardii (Lacertidae, Reptilia)

Cited by 46 publications

References 75 publications

Population structure and landscape genetics in the endangered subterranean rodent Ctenomys porteousi

Population structure and landscape genetics in the endangered subterranean rodent Ctenomys porteousi

Island size and remoteness have major conservation significance for how spatial diversity is partitioned in skinks

The effects of historical fragmentation on major histocompatibility complex class II β and microsatellite variation in the Aegean island reptile, Podarcis erhardii

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