Association Of Bryophyte Communities And Soil Habitat In Kanghe Nature Reserve Guangdong

Bryophytes are a very important biological component of forest ecosystem,which plays an important role in ecological functions,including conserving forest soil moisture,promoting nutrient cycling and reducing surface solar radiation.Here,we conducted a study on the community survey of bryophytes and soil habitat in the Kanghe Nature Reserve of Guangdong province,with 2 hectares plots,and we also collected soil samples for laboratory experiments to determine physicochemical properties.We aimed to analyze the effects of ecological environment on the diversity of bryophytes along a transect gradient,to reveal the relationship between bryophytes and the soil environment,to detect the bryophyte indicators of forest soils,and to address which species can be used as indicator species under specific soil factor gradients using multivariate statistical analysis methods.The main results are as follows:(1)We recorded a total of 37 bryophyte species from 33 genera and 23 families(including varieties)in the study site.Of which 11 species from 10 genera and 7 families were liverworts and 26 species from 23 genera and 16 families were mosses.There were a large number of single families,sinle generas and single species,and the dominant families and species were obvious.The floristic elements of the bryophytes were largely tropical elements.Temperate and East Asian elements respectively also had significant contributions.The elements endemic to China were the distinguishing feature of the flora in this research site.The results of life form analysis of bryophytes showed that wefts,mats and turfs were the richest.(2)The bryophytes in the study plot were classified into 10 plant communities by Two-Way Cluster Analysis.Species with similar ecological needs were clustered into a category and plot cells with similar environmental conditions were grouped into a group.The results of MRPP showed that it was sensitive to cluster bryophytes into 3 transects and bryophyte species composition significantly differed across three transects by overall comparison(P < 0.01).(3)The Kruskal-Wallis test,a nonparametric method,showed significant differences in functional diversity along transect gradient(P < 0.05),but no significant differeneces in species diversity(P > 0.05)except for the Shannon functional diversity index with marginally significant difference(P = 0.0571).These results indicated that the functional traits of bryophytes are effective indicators of environmental changes.Similar distribution patterns along a transect gradient were observed for total nitrogen,total phosphorus,alkaline nitrogen,available potassium,exchangeable calcium,exchangeable magnesium,available manganese,available zinc,and diversity of bryophytes with the highest values in transect 1 followed by transect 2 and the lowest values in transect 3,indicating that the nutrient distribution patterns may be related to the composition and distribution of bryophytes.(4)The result of Forward Stepwise Selection further showed that species diversity index of the bryophytes were significantly associated with soil p H,soil bulk density,total nitrogen,total phosphorus,and available boron(P < 0.05),and functional diversity index of the bryophytes were significantly associated with available potassium and available zinc(P < 0.05).(5)The result of Canonical Correspondence Analysis showed that bryophytes were highly significantly correlated with soil variables(P < 0.01).Soil bulk density,soil p H,total nitrogen,total phosphorus,alkaline nitrogen,available potassium,and exchangeable calcium were major limited factors for the composition and distribution of the bryophytes.(6)The result of Boosting Trees module showed that total phosphorus,exchangeable calcium and exchangeable magnesium had the greatest impact on species diversity of the bryophytes,and soil natural moisture content and total phosphorus had the greatest impact on functional diversity of the bryophytes,which indicated that soil factors were the main drivers for the diversity of bryophytes in this research scale.(7)The result of Indicator Species Analysis showed that 19 species were detected as significant indicators of forest soil habitat among 37 species of bryophytes.Among the 19 indicator species,11 species were detected as significantly indicators for various soil factors,and 8 species for a single soil factor.Aerobryopsis wallichii(Brid.)M.Fleisch.was a good indicator species of soil organic matter,and Chiloscyphus latifolius(Nees)J.J.Engel & R.M.Schust.was a good indicator species of total nitrogen,alkaline nitrogen and available potassium.