Biodiv Sci ›› 2021, Vol. 29 ›› Issue (4): 449-455.  DOI: 10.17520/biods.2020397

• Original Papers: Plant Diversity • Previous Articles     Next Articles

Effects of habitat fragmentation on population structure and dynamics of the endangered plant Pterospermum kingtungense

Guoping Yang1, Tao Wu2,3,4, Yunfen Geng2,3,4, Xiaoshuang Li2, Jiabo Hao2,3,4, Chunming Yuan2,3,4,*()   

  1. 1 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303
    2 Yunnan Academy of Forestry and Grassland, Kunming 650204
    3 Key Laboratory of Rare and Endangered Forest Plants of National Forestry and Grassland Administration, Kunming 650204
    4 Key Laboratory for Forest Silviculture and Resources Development of Yunnan Province, Kunming 650204
  • Received:2020-10-12 Accepted:2021-01-14 Online:2021-04-20 Published:2021-04-20
  • Contact: Chunming Yuan
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Aims: Habitat destruction and fragmentation are the leading cause of biodiversity loss. Therefore, it is necessary to understand the effect of fragmentation on plant population dynamics. The present study compared the population structure and dynamics of the endangered plant Pterospermum kingtungense in fragmented habitats of different sizes (5-ha and 15-ha) and continuous forests. We sought to identify the key life history stages that affect the population dynamics of P. kingtungense, with the goal of the providing a scientific basis for the formulation of endangered plant protection and management strategies.

Methods: Censuses were conducted over a one-year (2018-2019) period in three 50 m × 100 m sampling plots in each of the three habitats. All P. kingtungense plants were measured for DBH (diameter at breast height, but ground diameter for seedlings and saplings), height, survival, and seedling replenishment. Based on the investigated demographic parameters, annual transition matrices were established for each habitat to predict the population dynamics, and the relative contribution of the population demographic parameters to the population growth rate was quantified by the elastic analysis method of the matrix model.

Results: Across the two years, we recorded an average of 33.5, 82 and 87.5 P. kingtungense individuals in the 5-ha fragment, 15-ha fragment and continuous forest plots, respectively. Saplings dominated in the three habitats, but seedlings and big trees (comprising subadult and adult) are scarce in the 5-ha forest fragment, while seedlings are abundant in the 15-ha forest fragment. The population growth rate of P. kingtungense was equal to (15-ha fragment) or approaching (5-ha fragment and continuous forests) one, suggesting that P. kingtungense populations were stable in different size fragments and continuous forests. This stability is mainly due to the high survival rates of the populations in each life cycle stages. The survival rates of adult and subadult stages contribute substantially to the population growth rate, and these are the key life cycle stages affecting population dynamics in this species. Thus the protection of large trees (i.e., adults and subadults) is key to maintaining populations of the endangered plant P. kingtungense.

Conclusion: Our findings reveal that the population size of P. kingtungense decreased and its population structure altered in the small fragmented habitat, but the effect on the population dynamics may not yet have shown themselves. Therefore, it is feasible and valuable to protect and restore the endangered plant populations even in small, fragmented habitats.

Key words: habitat fragmentation, population dynamics, Lefkovitch matrix models, population growth rate, elasticity analysis