Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Community growth dynamics of Robinia pseudoacacia × Pinus tabuliformis reclamation pattern from the 17th to 22nd year in an open-pit coal mine waste dump in Loess area.

Abstract

Vegetation restoration is effective for ecological reclamation of mining areas. To study the community growth dynamics of artificial vegetation on reclaimed land in a mining area, a 0.8 hm2 permanent monitoring plot was established in 2010, with mixed forestry of locust trees(Robinia pseudoacacia) and Chinese pine(Pinus tabuliformis) at the Antaibao open-pit coal mine in Shanxi Province. Based on two datasets obtained in 2010 and 2015, we analyzed the dynamics of species composition, quantity, and DBH(Diameter at Breast Height) structure of the trees(DBH≥1 cm) from the 17th to 22nd year since reclamation. During this five-year period, the composition of the tree species was found to be relatively stable. The dominant species in the community continues to be R. pseudoacacia, albeit with significantly decreasing importance in contrast to the increasing importance of the invasive elm(Ulmus pumila). The herbaceous species reduced from 44 to 35, with the community composition tending to succeed from annual/biennial to perennial and from intermediate mesophyte to mesophyte. The number of trees(DBH≥1 cm) increased from 1530 to 2854 stands, of which 194 died and 1518 emerged, with an annual mortality and emergence rate of 2.71% and 15.18%. The highest mortality and emergence were each observed among the R. pseudoacacia and U. pumila. The basal area of the trees increased from 10.99 m2.hm-2 to 14.19 m2.hm-2, in which death led to the reduction of 0.65 m2.hm-2, while 3.85 m2.hm-2 was newly added. Interestingly, both, the largest decrease and increment of the basal area were observed in R. pseudoacacia. The mean DBH increased for R. pseudoacacia and P. tabuliformis, while it decreased for U. pumila. The smaller individuals had a higher mortality as opposed to the larger ones. The DBH distribution of the dead tree species was similar to that of living tree species in 2010. The population size of R. pseudoacacia and P. tabuliformis declined slightly, each at an annual rate of -2.88% and -0.24%, respectively, while that of U. pumila increased at an annual rate of at least 5%, with a significantly rapid growth of 33.37% in 5 years. With respect to the species composition and structure, great variations were observed in the mortality and emergence rates among different species, while considerable fluctuations were noted in community species and structure, indicating the instability of the reclaimed ecosystem.