Recovery Of Soil Collembola Biodiversity And Its Service To Management Policy-making In Degraded Grassland In Songnen Plain, China

It is becoming a giobal issue that biodiversity protection, especially the restorationof biodiversity of degradation ecosystem. Recently, the restoration of undergroundecosystem is getting more and more attention. Soil animals play a major role innutrient cycling, decomposition of organic matter and soil formation in theunderground ecosystem, which makes soil animals a crucial key in the ecosystemservices. Collembola, as one of the three groups of soil animals, shows highabundances and richness in soil and sensitive to the environment, has become animportant bioindicator in the recovery process in degraded ecosystems.In this paper, through the soil blocks transfer experiments and culturingcollembolan eggs in the soil, we tried to analysis the recovery potential of Collembolabiodiversity in three kinds of degraded land-use in degraded grassland in the SongnenPlain. By combining the analysis of grassland management policies we hope toprovide theoretical basis for the management technical of degraded grassland. Themain results are as follows:1. Collembola in degraded Songnen Plain showed high recovery potentiality whichconsists of dispersal recolonization and hatches from soil collembolan eggs bank.Land-use types showed significant effects on the recovery potential of Collembolaspecies diversity. The dispersal recolonization rates and abundances and theabundance and Collembola species diversity hatched from collembolan eggs bank inagriculture land is significantly higher than in grassland and significantly higher thanin BSAPs. More than50%of Collembola species could dispersed and recolonized the13cm wide soil blocks in2weeks, and nearly93%could disperse and recolonize in12weeks.2. Land-use types showed significant effects on the dispersal abilities of Collembola.The same species performed vary dispersal rates in different land uses types.Generally, the dispersal rates and recolonization abundances and biodiversity inagricultural land and grassland are higher than that in BSAPs. Compare to BSAPs, collembolan in agricultural land and grassland could reach to natural abundances inshorter time. Dominant species in each land-use types showed significantly higherdispersal rates and recolonization abundances. No apparently relationship between thecollembolan body structures and dispersal rates was found in our study.3. Collembolan egg banks in three kinds of land-use types are generally low. Theabundance and species diversities of collembolan egg bank in agricultural land issignificantly higher than in grassland and significantly higher than in BSAPs. Onaverage,318individuals and123individuals hatched from1Kg dry soil inagricultural land and grassland, respectively, while no collembolan hatched form soilin BSAPs. Soil environmental factors greatly affect the abundances of collembolanegg banks. Soils in agricultural land and grassland showed higher SOC and lower soilpH values.4. Moderate soil physical disturbance significantly increase the diversity andrichness of the soil collembolans. In the soil physical disturbance experiment, totally2105individuals were got and identified to11genus and13species. Higher abundanceand species diversity was found in grassland than in agricultural land and BSAPs afterphysical disturbance. Typically,127individuals from to7genus and8species ofCollembola were found after physical disturbance of BSAPs. Time significantlychanged the assemblage of Collembola, especially the dominant species in eachland-use types. Collembola densities and diversities in BSAPs were strongly affectedby sampling time, while no significant effects of sampling time on Collembola werefound in agricultural land and grassland.5. Overall, collembolans in Songnen Plain showed high recovery potential, both onthe dispersal recolonization and hatches from Collembolan egg bank. Artificial humanworks and natural revegetation process significantly increase dispersal recolonizationabundances and diversities and increase values of Collembola egg bank. Generally,human-made disturbances like reasonable grazing, fencing, sowing seeds and areconducive to resume underground soil animal diversity. Compare to natural recovery,manual intervention will accelerate the recovery of underground Collembolanbiodiversity and abundance.