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The patterns of isolation by distance (IBD) entailing increased genetic differentiation among populations have aroused extensive concerns for evolutionary biologists. Although the IBD may act on spatial processes contributing to the genetic differentiation among populations in anuran species, the factors shaping the IBD of frogs among populations in natural systems are largely unknown. Here, we studied the genetic differentiation among six populations with 24 individuals of the spotted‐leg treefrog along a latitudinal gradient (1860.31 km) based on 1020 single nucleotide polymorphisms from restriction site‐associated DNA sequencing. The results showed that the genetic diversity differed significantly among populations and that the insular populations had higher genetic diversity than the mainland populations. Furthermore, we also found a significant genetic differentiation among populations (FST = 0.277) and no sign of inbreeding (FUNI = −0.145). The IBD was detected for all populations, and a higher degree of the IBD was indicated when controlling for the effects of the isolation between Hainan and mainland populations caused by the Qiongzhou Strait. Our findings suggest that the form of the Qiongzhou Strait plays a key role in shaping the genetic diversity and population differentiation in treefrogs. [ABSTRACT FROM AUTHOR]

Microorganism plays an irreplaceable role in litter decomposition, and the dynamics of microbial activity in litter is of ecological significance in understanding the mechanism of litter decomposition. Therefore, the dynamic characteristics of microorganism in rubber litter decomposition were studied during 300 and 240 days by mesh bag method under different control measures in plantations. And the results were as following; (1) Microbial populations were closely related to litter residues and decomposition environments. The microbial population has been rising firstly and then falling on the ground but directly dropping under the ground by time. (2) Microbial populations under different environments as follows: 0.07 mm aperture of mesh bag > 1 mm aperture of mesh bag, non-fertile hole > fertile hole, underground group > ground group. During the entire process of decomposition, the quantity of bacteria holed absolute superiority, then actinomycetes, finally fungi. (3) Through the correlation analysis, the total number of bacteria, fungi and microorganism in aboveground group was significantly associated with the decomposition rate, but there was little correlation to actinomycetes. It's suggested that fungi and bacteria are the main participants in litter decomposition on the ground. In underground group, the microbial groups were significantly or extremely significantly related to the dry weight of residues, but was not correlated to decomposition rate significantly, which suggested that litter provided food for underground microbes, and litter decomposition was more dependent on comprehensive effect of microbes, soil animals and soil environments. [ABSTRACT FROM AUTHOR]

Zinc isotopes have been increasingly utilized as a proxy for (bio)geochemical cycles of nutrient Zn in the ecosystem like soils, but the behavior and mechanism of Zn isotope fractionation during weathering and soil formation remain to be constrained. Here we reported zinc contents and isotope data for saprolites and laterites from two well-characterized mafic-rock weathering profiles, formed under a subtropical climate (South Carolina, USA) and a tropical climate (Hainan Island, China), respectively. Leaching experiments with basalt and andesite as the starting materials were also performed for comparison. The leaching results revealed no resolvable Zn isotope fractionation during dissolution of silicate minerals in the absence of organic ligands in solutions. The Hainan laterites show strong Zn depletion and have lower δ66Zn Lyon values (0.10‰ to 0.27‰) relative to the parent rock (0.31 ± 0.04‰), which are coupled with light copper isotope compositions in the same samples. These observations suggest that Zn mobilization was achieved via metal-organic complexation and Fe-colloids transportation. By contrast, saprolites from the South Carolina are extremely Zn-rich (ten-fold higher concentration than the parent rock) and most samples have higher δ66Zn values (0.10‰ to 0.65‰) compared with the parent rock (0.24 ± 0.04‰). Zinc isotope ratios of the South Carolina profile are positively correlated with iron isotope ratios (δ56Fe) and Fe3+/Fe Total , the latter of which is related to secondary Fe (hydr)oxide formation. These relationships link the high Zn contents and δ66Zn values of saprolites from the South Carolina profile to the substantial adsorption of Zn onto or isomorphic substitution into Fe (hydr)oxides that prefers heavier Zn isotopes. Our study highlights that Fe (hydr)oxides exert a strong influence on the re-distribution of nutrient Zn in natural soils and the (bio)geochemical cycling in natural soil systems. [ABSTRACT FROM AUTHOR]