Vegetation Structure, Species Diversity, and Ecosystem Processes as Measures of Restoration Success

Background

This article provides an example of how to evaluate forest restoration using integrative methods, including measures of vegetation structure, species diversity, and ecosystem processes. Specifically discussed are four measures of vegetation structure, four measures of species diversity, and six measures of ecosystem processes.

Research Goals & Methods 

The research aimed to measure the degree of restoration that occured at a site in Sabana Seca, Puerto Rico, a subtropical moist forest, compared with a reforested site and a pre-reforested site, all of which were Karst valleys previously dominated by grasses.

Conclusions & Takeaways

When comparing the vegetation structure of pre-reforested, reforested, and reference sites, the author found the following: the pre-reforested site had the fewest number of stems, the highest percentage of herbaceous cover, and litter cover dominated by herbaceous vegetation; the reference site had the highest number of stems, lowest percentage of herbaceous cover, and litter structure dominated by woody species; the reforested site had intermediate number of stems, percentage of litter cover, and a litter layer dominated by pioneer species. The author also found that species diversity tended to increase from the pre-reforested site to the reforested site, with the highest diversity observed in the reference site. While litterfall and nitrogen levels were higher in the reforested and reference sites, other nutrient measures varied little between the tree sites. There was no difference between weight of eartheworms at each site, which were measured as a possible indicator of nutrient cycling. Using the Bray Curtis Ordination as a measure of restoration success, the author found that most measures of vegetation structure and species diversity recovered by greater than 50% at the reforestation site. Ecosystem services, meanwhile, had the slowest rate of recovery.