Reintroducing effects and influencing factors of Taxus cuspidata population

  Objective  Reintroduction is an important method for endangered species conservation and population restoration. Taking Taxus cuspidata, a critically endangered wild plant with extremely small population, as the research object, this study chose three different forest types and two groups of different age T. cuspidata seedlings for field reintroduction tests, studied the reintroducted forest type suitable for T. cuspidate and the main factors influencing seedling growth and survival during reintroduction process. It is hopefully to provide scientific evidence for the conservation of T. cuspidata.

  Method  Betulaplatyphylla-Populus cathayana forest, Pinus koraiensis-spruce-fir forest and P. koraiensis-Tilia amurensis forest were selected as the reintroduction experimental forest types, indexes such as soil factors and topographic factors were investigated, and indexes such as seedling livability, seedling height, basal diameter and crown breadth were investigated monthly. Difference significance analysis and multiple comparison were conducted for each growth index of seedlings, and the influencing factors of reintroducted seedling growth were studied through grey correlation analysis and other methods.

  Result  The very year survival rate of reintroducted seedlings of T. cuspidata was more than 86%. The ground diameter, seedling height and crown width all increased, except for the seedling height growth of T. cuspidata in 1−2 years, the growth indexes of T. cuspidata seedlings of all forest types showed no significant variations. The 1−2 years old T. cuspidata seedlings of P. koraiensis-T. amurensis forest were significantly higher than that of B. platyphylla-P. cathayana forest and P. koraiensis-spruce-fir forest. As it was during the overwintering period, 4−5 years old T. cuspidata seedlings were eaten by roe deer, their survival rate decreased significantly, and the growth rate was very poor; the growth of 1−2 years old seedlings was also affected to some extent by long-term low temperature stress. The survival and growth of reintroducted seedlings of T. cuspidata were affected by diversified environmental factors, among which, the most relevant was forest type, followed by slope aspect, slope degree and canopy density, while the association degree of soil chemical property index was less.

  Conclusion  The effect of reintroduction of 4−5 years old T. cuspidata seedlings is poor due to predation of animals. 1−2 years old seedlings adapt to the three habitats of B. platyphylla-P. cathayana forest, P. koraiensis-spruce-fir forest and P. koraiensis-T. amurensis forest, and the optimum forest type for the seedling reintroduction of 1−2 years old is P. koraiensis-T. amurensis forest. Forest type, slope aspect, slope degree and light are the primary environmental factors influencing the reintroduction of T. cuspidata.