Limits...
Sex-biased dispersal of a frog (Odorrana schmackeri) is affected by patch isolation and resource limitation in a fragmented landscape.

Wang Y, Lane A, Ding P - PLoS ONE (2012)

Bottom Line: The effects of four island attributes and two potential impact factors on the pattern of sex-biased dispersal were examined.We found that the extent of isolation from the mainland and the number of breeding sites both showed a negative correlation with female biased dispersal, such that the closer an island is to the mainland the more likely it is to display female biased dispersal, and the more breeding sites on an island the more male immigrants.Based on these results, we conclude that geographic isolation and limited breeding resources are the most likely explanation for the patterns of dispersal observed in this fragmented population of amphibians.

View Article: PubMed Central - PubMed

Affiliation: The Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou, China.

ABSTRACT
Sex-biased dispersal is widespread in the animal kingdom and is affected by numerous factors including mating system, social factors and environmental conditions. Unlike birds and mammals, there is no common trend in amphibians and explaining the direction and degree of sex-biased dispersal in species-specific cases is difficult. We conducted a study on dispersal of the Chinese piebald odorous frog (Odorrana schmackeri) in a fragmented landscape associated with dam construction. Ten microsatellite loci were used to analyze 382 samples sourced from 14 fragmented 'islands'. Assignment tests indicated a significant pattern of female-biased dispersal on one island with inconsistencies in the strength and direction of this pattern between nearby islands. The effects of four island attributes and two potential impact factors on the pattern of sex-biased dispersal were examined. We found that the extent of isolation from the mainland and the number of breeding sites both showed a negative correlation with female biased dispersal, such that the closer an island is to the mainland the more likely it is to display female biased dispersal, and the more breeding sites on an island the more male immigrants. Based on these results, we conclude that geographic isolation and limited breeding resources are the most likely explanation for the patterns of dispersal observed in this fragmented population of amphibians.

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Variation partitions of effects of island isolation and the number of breeding sites on the disparity AIc.Island isolation explained more than the number of breeding sites and isolation play a more significant role in sex-biased dispersal. BS: the number of breeding sites.
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pone-0047683-g003: Variation partitions of effects of island isolation and the number of breeding sites on the disparity AIc.Island isolation explained more than the number of breeding sites and isolation play a more significant role in sex-biased dispersal. BS: the number of breeding sites.

Mentions: All six parameters (A, I, PAR, SI, SR and BS) did not show evidence of multicollinearity. After backward stepwise analysis (Table S1), island isolation (I) and the number of breeding sites (BS) showed significant negative relationships with the disparity AIc. The average value of island isolation and the number of breeding sites are 718.71±257.76 (from 250 to 1121) and 62.86±39.39 (from 25 to 167), respectively. The best fit model was: dAIc = 1.630−0.001 * I−0.005 * BS (R2 = 0.543, F = 8.736, P = 0.005). The variance partitioning results showed that island isolation and the number of breeding sites explained 20% and 3% independently, but explained 31% together (Figure 3). The other four parameters displayed no correlation with disparity AIc. The average sex ratio value is 0.995±0.419 (ranged from 0.367 to 1.875) and Chi-square tests showed that there were no significant deviations from 1, except on island 2 (χ2 = 8.805, P = 0.003).


Sex-biased dispersal of a frog (Odorrana schmackeri) is affected by patch isolation and resource limitation in a fragmented landscape.

Wang Y, Lane A, Ding P - PLoS ONE (2012)

Variation partitions of effects of island isolation and the number of breeding sites on the disparity AIc.Island isolation explained more than the number of breeding sites and isolation play a more significant role in sex-biased dispersal. BS: the number of breeding sites.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3475718&req=5

pone-0047683-g003: Variation partitions of effects of island isolation and the number of breeding sites on the disparity AIc.Island isolation explained more than the number of breeding sites and isolation play a more significant role in sex-biased dispersal. BS: the number of breeding sites.
Mentions: All six parameters (A, I, PAR, SI, SR and BS) did not show evidence of multicollinearity. After backward stepwise analysis (Table S1), island isolation (I) and the number of breeding sites (BS) showed significant negative relationships with the disparity AIc. The average value of island isolation and the number of breeding sites are 718.71±257.76 (from 250 to 1121) and 62.86±39.39 (from 25 to 167), respectively. The best fit model was: dAIc = 1.630−0.001 * I−0.005 * BS (R2 = 0.543, F = 8.736, P = 0.005). The variance partitioning results showed that island isolation and the number of breeding sites explained 20% and 3% independently, but explained 31% together (Figure 3). The other four parameters displayed no correlation with disparity AIc. The average sex ratio value is 0.995±0.419 (ranged from 0.367 to 1.875) and Chi-square tests showed that there were no significant deviations from 1, except on island 2 (χ2 = 8.805, P = 0.003).

Bottom Line: The effects of four island attributes and two potential impact factors on the pattern of sex-biased dispersal were examined.We found that the extent of isolation from the mainland and the number of breeding sites both showed a negative correlation with female biased dispersal, such that the closer an island is to the mainland the more likely it is to display female biased dispersal, and the more breeding sites on an island the more male immigrants.Based on these results, we conclude that geographic isolation and limited breeding resources are the most likely explanation for the patterns of dispersal observed in this fragmented population of amphibians.

View Article: PubMed Central - PubMed

Affiliation: The Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou, China.

ABSTRACT
Sex-biased dispersal is widespread in the animal kingdom and is affected by numerous factors including mating system, social factors and environmental conditions. Unlike birds and mammals, there is no common trend in amphibians and explaining the direction and degree of sex-biased dispersal in species-specific cases is difficult. We conducted a study on dispersal of the Chinese piebald odorous frog (Odorrana schmackeri) in a fragmented landscape associated with dam construction. Ten microsatellite loci were used to analyze 382 samples sourced from 14 fragmented 'islands'. Assignment tests indicated a significant pattern of female-biased dispersal on one island with inconsistencies in the strength and direction of this pattern between nearby islands. The effects of four island attributes and two potential impact factors on the pattern of sex-biased dispersal were examined. We found that the extent of isolation from the mainland and the number of breeding sites both showed a negative correlation with female biased dispersal, such that the closer an island is to the mainland the more likely it is to display female biased dispersal, and the more breeding sites on an island the more male immigrants. Based on these results, we conclude that geographic isolation and limited breeding resources are the most likely explanation for the patterns of dispersal observed in this fragmented population of amphibians.

Show MeSH
Related in: MedlinePlus