Previous work found that different Japanese lineages of salamanders had quite different levels of species and genetic diversity. Lineages vary from having one to several species and the extent of genetic variation amo...Previous work found that different Japanese lineages of salamanders had quite different levels of species and genetic diversity. Lineages vary from having one to several species and the extent of genetic variation among lineages differs substantially. Most speciose,genus Hynobius contains 18 species and several potential cryptic species. We explore genetic diversity in this genus by combining comprehensive sampling and mitochondrial DNA sequences. Based on this and previous analyses of salamanders,relative times of divergence are employed to evaluate the relationship between age and diversity among the four major lineages whose distributions broadly overlap on the islands. For Hynobius,our analyses are congruent with the previously reported high level of cryptic diversity in morphology and allozymes,particularly in species composed of non-sister matrilines. Both species and genetic diversity correlate with the relative ages of the lineages. This correlation indicates that the variation in levels of diversity can be explained,to a considerable extent,by the hypothesis that older insular lineages have accumulated greater diversity. In addition to the Korean Peninsula,H. leechii might have survived in another Pleistocene glacial refugium north of the peninsula and this refugium provided a source of colonization after the last glacial maximum.展开更多
Aims The aim of the study was to discover what set of variables best explains the transition from warm to mesic forest vegetation.Based on various variables grouped into sets(geomorphological,ecological,structural,soi...Aims The aim of the study was to discover what set of variables best explains the transition from warm to mesic forest vegetation.Based on various variables grouped into sets(geomorphological,ecological,structural,soil characteristics and chorological),six models were built and tested by generalized additive mixed models(GAMMs).We assumed that each set of variables has different explanatory power.Our aim was to compare the six different models(sets of variables),to test which model best explains the species turnover in forest communities along the transition between warm and mesic temperate forests and to try to find reasons for the different explanatory power of the models.Methods The research took place in the southern part of the Balkan Peninsula.Field sampling was done according to standard methods.The gradient from warm to mesic forests was defined as the turnover of species and evaluated by projection of samples on the first unconstrained DCA axis.Geomorphological,ecological,structural and soil characteristics,together with chorological sets of variables,were regressed on the turnover of species composition.Based on the five sets of variables,six models were constructed and tested by generalized additive mixed models.Important Findings Ecological conditions best explain the change of forest communities along the gradient;evolution and the development of vegetation reflected in chorotypes are also of high importance;geomorphology and structure seem not to change so dramatically and soil shows the least significant differences of all.Ecological variables are the most important set of variables in the transition between warm and mesic temperate forests but eco-evolutionary dynamics after the Pleistocene should also be taken into consideration.展开更多
基金supported by the Chinese Academy of Sciences (09C3011100, KSCX2- YW-Z-0906, KSCX2-EW-J-22)the National Natural Science Foundation of China (NSFC-30870287, NSFC-30900134)the Natural Sciences and Engineering Research Council (Canada) Discovery Grant 3148
文摘Previous work found that different Japanese lineages of salamanders had quite different levels of species and genetic diversity. Lineages vary from having one to several species and the extent of genetic variation among lineages differs substantially. Most speciose,genus Hynobius contains 18 species and several potential cryptic species. We explore genetic diversity in this genus by combining comprehensive sampling and mitochondrial DNA sequences. Based on this and previous analyses of salamanders,relative times of divergence are employed to evaluate the relationship between age and diversity among the four major lineages whose distributions broadly overlap on the islands. For Hynobius,our analyses are congruent with the previously reported high level of cryptic diversity in morphology and allozymes,particularly in species composed of non-sister matrilines. Both species and genetic diversity correlate with the relative ages of the lineages. This correlation indicates that the variation in levels of diversity can be explained,to a considerable extent,by the hypothesis that older insular lineages have accumulated greater diversity. In addition to the Korean Peninsula,H. leechii might have survived in another Pleistocene glacial refugium north of the peninsula and this refugium provided a source of colonization after the last glacial maximum.
基金National Park Galičica,Research Centre of the Slovenian Academy of Sciences and Arts,Slovenian Research Agency(P1-0236).
文摘Aims The aim of the study was to discover what set of variables best explains the transition from warm to mesic forest vegetation.Based on various variables grouped into sets(geomorphological,ecological,structural,soil characteristics and chorological),six models were built and tested by generalized additive mixed models(GAMMs).We assumed that each set of variables has different explanatory power.Our aim was to compare the six different models(sets of variables),to test which model best explains the species turnover in forest communities along the transition between warm and mesic temperate forests and to try to find reasons for the different explanatory power of the models.Methods The research took place in the southern part of the Balkan Peninsula.Field sampling was done according to standard methods.The gradient from warm to mesic forests was defined as the turnover of species and evaluated by projection of samples on the first unconstrained DCA axis.Geomorphological,ecological,structural and soil characteristics,together with chorological sets of variables,were regressed on the turnover of species composition.Based on the five sets of variables,six models were constructed and tested by generalized additive mixed models.Important Findings Ecological conditions best explain the change of forest communities along the gradient;evolution and the development of vegetation reflected in chorotypes are also of high importance;geomorphology and structure seem not to change so dramatically and soil shows the least significant differences of all.Ecological variables are the most important set of variables in the transition between warm and mesic temperate forests but eco-evolutionary dynamics after the Pleistocene should also be taken into consideration.