Chin J Plan Ecolo ›› 2015, Vol. 39 ›› Issue (10): 990-1002.DOI: 10.17521/cjpe.2015.0096

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Quantitative classification of the subtropical evergreen-deciduous broadleaved mixed forest and the deciduous and evergreen species composition structure across two national nature reserves in the southwest of Hubei, China

HUANG Yong-Tao1,2, YAO Lan1, AI Xun-Ru1, LÜ Shi-An3, DING Yi2,4,*()   

  1. 1School of Forestry and Horticulture, Hubei University for Nationalities, Enshi, Hubei 445000, China
    2Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
    3Xingdoushan National Nature Reserve, Enshi, Hubei 445000, China
    4Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
  • Online:2015-10-01 Published:2015-10-24
  • Contact: Yi DING
  • About author:

    # Co-first authors

Abstract: <i>Aims</i>

The subtropical evergreen-deciduous broadleaved mixed forest is the largest extant natural vegetation type in southwest Hubei. However, little knowledge exists on the types and compositions (especially the relative ratios of evergreen versus deciduous species) of this forest vegetation. Here, we quantitatively classify the less studied forest vegetation into different community types, compare their size and composition structure, and analyze species-environment relationships which is the basis for further understanding the biodiversity maintenance mechanism and reasonable protection and utilization of this forest.

<i>Methods</i>

We established 92 20 m × 20 m plots of subtropical evergreen-deciduous broadleaved mixed forest in two national nature reserves in Enshi, Hubei Province, China. All species with stems ≥1 cm diameter at breast height (DBH) in each plot were identified and mapped. These plots were classified by using two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA). The species richness, abundance, basal area and importance value were chosen to compare structure, species composition and evergreen and deciduous ratio. Permutation-based multiple regression on distance matrices and multiple stepwise regression analysis were used to examine the relationship between species distribution and environmental factors.

<i>Important findings</i>

Our results showed that the subtropical evergreen-deciduous broadleaved mixed forest in the southwest of Hubei could be classified into five community types based on quantitative methods: i.e. Cyclobalanopsis glauca-Eurya alata + Camellia cuspidate (community type I), Carpinus fargesiana + Cyclo- balanopsis glauca-Eurya alata (community type II), Carpinus fargesiana + Cyclobalanopsis glauca-Weigela japonica (community type III), Fagus lucida + Cyclobalanopsis multinervis-Eurya alata (community type IV) and Carpinus fargesiana + Daphniphyllum macropodum + Lithocarpus cleistocarpus-Eurya alata (community type V). Species richness, abundance, basal area and importance value of evergreen and deciduous species in each community types were different. Deciduous species in community II, community III and community V were significantly higher than evergreen species in terms of species richness, stem abundance, basal area and importance value, but they had no significant differences in community I and community IV. The richness of deciduous species in most community types were higher than those of evergreen species, meanwhile the abundance, basal area and importance value of deciduous species in the small size classes (1 cm ≤ DBH < 5 cm) in each community types were lower than those of evergreen species. In middle size classes (5 cm ≤ DBH < 10 cm), the richness, abundance, basal area and importance value of deciduous species were higher than those of evergreen species in community II, community III and community V. However, in community I and community IV, the evergreen species were larger than deciduous species in the four indexes. The richness of deciduous species in majority of the community types were higher than those of evergreen species in large size classes (DBH ≥ 10 cm). The elevation, slope and aspect, soil total nitrogen content, soil total phosphorus content, soil available nitrogen content and soil available phosphorus content were the major factors affecting evergreen and deciduous species distribution across the five community types.

Key words: community type, the evergreen-deciduous broadleaved mixed forest, environmental factors, ratio of deciduous and evergreen species, quantitative classification