摘要
Testate amoebae are sensitive indicators of substrate moisture in peaflands. Over the last decades, they have been studied to reconstruct hydrological changes since the Holocene. However, these studies have been geographically restricted to North America and Europe. We conducted the first investigation of testate amoebae on the largest continental fresh water wetland in the Sanjiang Plain, China. The objectives of this study were to provide baseline data on the ecology of testate amoebae in the peatlands of Northeast China and to assess the potential of using them as environmental indicators in this ecosystem. We examined modem testate amoeba assemblages and species-environmental relationships at 46 microsites within 5 waterlogged depressions. The environmental parameters measured included： depth to water table, pH, and loss on ignition. The results showed that the dominant species were Trinema complanatum type, Euglypha rotunda type, Euglypha strigosa type, and Centropyxis cassis type. Redundancy analysis demonstrates that water table depth has the most important effect on testate amoeba assemblages, explaining 16.7% （p=0.002） of the total variance, pH was not a statistically significant factor for testate amoeba assemblages. Weighted averaging and weighted averaging partial least squares models were used to build transfer functions for depth to water table. The best performing transfer function was generated by the weighted averaging partial least squares model with an r^2LOSO of 0.62 and RMSEPLoso of 6.96 era. Results indicate that testate amoebae in waterlogged depression peatland have the potential to be used as indicators for hydrological changes and for palaeohydrologic reconstructions in the Sanjiang Plain.
Testate amoebae are sensitive indicators of substrate moisture in peaflands. Over the last decades, they have been studied to reconstruct hydrological changes since the Holocene. However, these studies have been geographically restricted to North America and Europe. We conducted the first investigation of testate amoebae on the largest continental fresh water wetland in the Sanjiang Plain, China. The objectives of this study were to provide baseline data on the ecology of testate amoebae in the peatlands of Northeast China and to assess the potential of using them as environmental indicators in this ecosystem. We examined modem testate amoeba assemblages and species-environmental relationships at 46 microsites within 5 waterlogged depressions. The environmental parameters measured included： depth to water table, pH, and loss on ignition. The results showed that the dominant species were Trinema complanatum type, Euglypha rotunda type, Euglypha strigosa type, and Centropyxis cassis type. Redundancy analysis demonstrates that water table depth has the most important effect on testate amoeba assemblages, explaining 16.7% （p=0.002） of the total variance, pH was not a statistically significant factor for testate amoeba assemblages. Weighted averaging and weighted averaging partial least squares models were used to build transfer functions for depth to water table. The best performing transfer function was generated by the weighted averaging partial least squares model with an r^2LOSO of 0.62 and RMSEPLoso of 6.96 era. Results indicate that testate amoebae in waterlogged depression peatland have the potential to be used as indicators for hydrological changes and for palaeohydrologic reconstructions in the Sanjiang Plain.
基金
Acknowledgements We cordially thank Dr. Xuefeng Wang and Mr. Xiumin Yan （Northeast Institute of Geography and Agroecology, CAS, China） for their help with the field sampling, Mr. Dehua Mao （Northeast Institute of Geography and Agroecology, CAS, China） for providing the research site map, and Prof. Jun Yang and Dr. Yangmin Qin for helpful suggestions for improvement and species identifications. We are also deeply grateful to Dr. Louise Loudermilk （Forest Service Station of USDA, USA） and Dr. Mark Judson （Mus6um National d＇HistoireNaturelle, France） for comments on the manuscript and English language revisions. Lastly, we thank three anonymous reviewers for constructive comments that helped improve the manuscript. Financial assistance was provided by the National Basic Research Program of China （Nos. 2012CB956103 and 2010CB951304）, the National Natural Science Foundation of China （Grant No. 41371261）, and the CAS/SAFEA International Partnership Program for Creative Research Teams （KZZD-EW-TZ-07）.
