Biodiv Sci ›› 2004, Vol. 12 ›› Issue (2): 237-244.DOI: 10.17520/biods.2004028

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Altitudinal changes in species diversity and community structure of Abies fabri communities at Hailuo Valley of Mt. Gongga, Sichuan

SHEN Ze-Hao, LIU Zeng-Li, FANG Jing-Yun   

  1. Deparment of Ecology,and Key Laboratory for Earth Surface Processes of the Ministry of Education,Peking University,Beijing 100871
  • Received:2003-06-12 Revised:2003-09-10 Online:2004-03-20 Published:2004-03-20

Abstract: Abies fabri is the dominant species of sub-alpine coniferous forest on the east slope of Mt. Gongga, distributing up to the alpine treeline. Nineteen tree plots dominated by A. fabri were sampled along the altitudinal gradient, covering the vertical range of the species in Hailuo Valley. Altitudinal patterns of community structure and species diversity were analyzed. Major results include:(1) The 19 plots were classified into 5 community types by TWINSPAN, including mixed A. fabri + Picea brachytyla +Tsuga dumosacommunity, A. fabri +deciduous tree-mixed shrub community, A. fabri +broadleaf trees- Bashania fangiana community, A. fabri-shrubs-lichen community, and A. fabri-Rhododendron spp.-lichen community. The spatial differentiation between the community types were mainly controlled by elevation and micro-topographic features, e.g. slope and position. (2) Species richness and the Shannon-Wiener index of the canopy and shrub layers decreased with increasing elevation, whereas no trend was detected in the herb layer. (3) The β diversity indices of each layer decreased with increasing elevation. The difference in species composition decreased above an elevation of 3300 m. (4) Maximum tree height, mean tree height, maximum DBH, and mean DBH of A. fabri forests decreased with increase of elevation. Environmental limitations near timberline to the height and girth growth of A. fabri individuals became clear above 3550 m a.s.l., whereas stem densities of all species or A. fabri with DBH>5 cm increased as elevation rose. (5) The average timber volume of A. fabri was 846.4 m3/hm2, and declined with increase of elevation.