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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Related in: MedlinePlus

Map of study area and sampling sites.Black triangles show sampling distribution of Odorrana schmackeri in Thousand Island Lake of Zhejiang Province, China. Grey represents land, white indicates water.
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pone-0047683-g001: Map of study area and sampling sites.Black triangles show sampling distribution of Odorrana schmackeri in Thousand Island Lake of Zhejiang Province, China. Grey represents land, white indicates water.

Mentions: We collected frog samples via toe-clip during June and August (breeding season) of 2010 (Table 1, Figure 1). Quadrat method (100 m×3 m) was used to direct the sampling of frogs at the hydro-fluctuation zone of each island, which varies seasonally as a result of precipitation rates. Only tissue samples of adult frogs were utilized as the gender of subadult frogs which a snout-vent length less than four centimetres [25] could not be determined in O. schmackeri. Male adults were determined by the presence of nuptial pads during the breeding season. All samples were captured by hand, and tissue samples were stored in 95% ethanol for laboratory analysis.


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)

Map of study area and sampling sites.Black triangles show sampling distribution of Odorrana schmackeri in Thousand Island Lake of Zhejiang Province, China. Grey represents land, white indicates water.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0047683-g001: Map of study area and sampling sites.Black triangles show sampling distribution of Odorrana schmackeri in Thousand Island Lake of Zhejiang Province, China. Grey represents land, white indicates water.
Mentions: We collected frog samples via toe-clip during June and August (breeding season) of 2010 (Table 1, Figure 1). Quadrat method (100 m×3 m) was used to direct the sampling of frogs at the hydro-fluctuation zone of each island, which varies seasonally as a result of precipitation rates. Only tissue samples of adult frogs were utilized as the gender of subadult frogs which a snout-vent length less than four centimetres [25] could not be determined in O. schmackeri. Male adults were determined by the presence of nuptial pads during the breeding season. All samples were captured by hand, and tissue samples were stored in 95% ethanol for laboratory analysis.

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