Biodiv Sci ›› 2020, Vol. 28 ›› Issue (4): 463-473.DOI: 10.17520/biods.2019283

• Original Papers: Plant Diversity • Previous Articles     Next Articles

Structure and spatial distribution pattern of a native Metasequoia glyptostroboides population in Hubei

Xiao Huang1,Jiang Zhu1,2,*(),Lan Yao1,2,Xunru Ai1,2,Jin Wang1,Manling Wu1,Qiang Zhu1,Shaolin Chen3   

  1. 1 School of Forestry and Horticulture, Hubei Minzu University, Enshi, Hubei 445000
    2 Key Laboratory of Biological Resources Protection and Utilization of Hubei Province, Hubei Minzu University, Enshi, Hubei 445000
    3 Hubei Xingdoushan National Nature Reserve Administration, Enshi, Hubei 445000
  • Received:2019-09-08 Accepted:2019-11-27 Online:2020-04-20 Published:2020-06-15
  • Contact: Jiang Zhu

Abstract:

Metasequia glyptostroboides is an endemic and endangered species in China, and has therefore been heavily researched. M. glyptostroboides’ distribution seems to have a recognizable spatial pattern, with a clear potential mechanism. To test this, we analyzed the structure and diameter classes and height level classes from survey data of parent M. glyptostroboides trees with a pairwise correlation function g (r) and three null models (complete spatial randomness, heterogeneous Poisson process, and antecedent condition) in a point pattern analysis. The results of the spatial distribution patterns showed that: (1) There was 5,661 individuals of the native M. glyptostroboides population in the study area. Within this population, 31 of which were dead, 40 trees were on the verge of death, and 465 trees were classified as “weak”, with morphological characteristics and growth conditions associated with these trees such as shoot breakage, ant damage, and lightning strike. (2) Both the diameter-class structure and the height-class structure were spindle-shaped, with poor natural renewal; (3) Based on Complete Spatial Randomness, the native M. glyptostroboides population showed a random distribution at all scales, the middle- aged trees showed an aggregation distribution on a small scale (r < 3,300 m), and the adult trees and the older trees appeared an aggregation distribution on a larger scale (r < 4,700 m). The aggregation scales of the population and the different age groups were 0-3,000 m, 0-2,100 m, 0-2,900 m and 0-2,500 m, respectively, and followed a weak random distribution and uniform distribution. (4) Based on Complete Spatial Randomness, there were positive correlations between the three growth stages at all scales that weakened when habitat heterogeneity was excluded (only a positive correlation between 0-2,800 m). In summary, the M. glyptostroboides population is decreasing gradually with poor population regeneration. The population is presented mainly as cluster distribution with positive relationship among all age classes, due to habitat heterogeneity, diffusion limitation and intra-species competition according to the existing spatial pattern.

Key words: Metasequoia glyptostroboides, population structure, point pattern analysis, space correlation