Chin J Plant Ecol ›› 2014, Vol. 38 ›› Issue (5): 477-490.DOI: 10.3724/SP.J.1258.2014.00044

• Research Articles • Previous Articles     Next Articles

Plant diversity and seasonal dynamics in forest gaps of varying sizes in Pinus massoniana plantations

CUI Ning-Jie1,ZHANG Dan-Ju1,LIU Yang1,ZHANG Jian1,2,*(),YANG Wan-Qin1,OU Jiang1,ZHANG Jie1,SONG Xiao-Yan1,YIN Rui1   

  1. 1Institute of Ecology & Forestry, College of Forestry, Sichuan Agricultural University, Chengdu, 611130, China
    2Key Laboratory of Ecological Forestry Engineering in Sichuan Province, Ya’an, Sichuan 625014, China
  • Received:2013-10-09 Accepted:2014-03-28 Online:2014-05-01 Published:2014-05-13
  • Contact: ZHANG Jian

Abstract:

Aims Pinus massoniana is the major plantation tree species in the low hilly lands of the upper Yangtze river valley for commercial purpose. The large areas of plantations have caused serious ecological problems such as biodiversity decline and soil degradation. Our objectives were to study the dynamics of species composition and plant diversity in forest gaps, to test the hypothesis that forest gaps facilitate the regeneration and plant diversity in P. massoniana plantations, and to determine the size of forest gaps that harbors the most complex compositional structure and the greatest plant diversity.
Methods We selected 39-year-old P. massoniana plantations with seven different gap sizes in the study, and used combination of systematic and representative sampling approaches. In the spring, summer, and autumn of 2013, sampling plots of the dimension 5 m × 5 m were laid out in the center of the forest gaps and under the canopy, and plants within each plot were surveyed for determination of their diversity and compositional structure.
Important findings The understory of P. massoniana plantations were dominated by phanerophyte plants, followed by hemicryptophytes, geophytes, and therophyte plants. The phanerophyte plants were more abundant under the canopy than in forest gaps. The large gaps had more phanerophyte plants, while the geophytes and therophyte plants were less frequent under the canopy than in the small gaps. The species richness and diversity were significantly lower under the canopy than in the large forest gaps. Moreover, species richness, dominance, and diversity differed significantly among the forest gaps of different sizes. Seasonally, the highest diversity occurred in summer, followed by autumn, with the spring having the lowest diversity. The greatest diversity was found in the forest gaps of the size 1225-1600 m2, which could be the optimal gap size for facilitating plant diversity and regeneration of vegetation in P. massoniana plantations.

Key words: gap, life form, Pinus massoniana plantation, plant diversity, season