Changing richness of plant species aids reclamation on smelter-damaged lands in Sudbury, Ontario, Canada

Twenty-five years following Sudbury's initial land reclamation efforts, birch and poplar are regenerating and pine seedlings are thriving. However, in a recent review of the Sudbury Land Reclamation Program, it was suggested that forest diversity is poor in the reclaimed lands. Ecological succession appears delayed and many understory woodland species are absent. A vegetative survey on these sites revealed that few of the desired understory species are re-colonizing the developing forests. Three methods were tested to determine the best manner to introduce them to the community: translocation of individuals, forest floor transplants (sods), and applications of duff. Plant matter was introduced during the fall of 2003 to old sites (20-25 years since reclamation in the form of liming, and tree planting), middle-aged sites (15-20 years since reclamation), and young sites (<10 years since reclamation) located throughout Coniston and Falconbridge, Ontario. Observations three years following introduction indicate that the use of sods is the most successful method employed, with 100% of the sods adding at least one new species to the site. Greenhouse experiments examining propagation techniques have demonstrated successful plant reproduction by seed in 70% of the species tested, with many typical Ontario pine forest herbs reproducing successfully by stolons and rhizomes. The process of utilizing vegetation in nodes to colonize adjacent areas facilitates the successional development of reclaimed forests, enabling the re-introduction of understory woodland species to disturbed lands and provides a practical means of increasing the overall plant diversity in severely disturbed environments.