Is Succession-based Management of Coastal Dune Forest Restoration Valid?

Abstract

Habitat restoration and the theory of ecological succession are linked intrinsically. However, restoration management does not always rely on successional principles. This separation between theory and practical application may stem from the failure of succession to achieve restoration targets. Here we test the predictions of succession in a restoration context to ascertain the validity of succession-based management. Specifically we answer the following 4 questions: 1) does the rate of species turnover decrease as coastal dune forest develops; 2) is there a sequence of changing species “types” from pioneer species adapted to harsh conditions to species adapted to high levels of competition; 3) is this sequence of types directional and the same across all sites with similar climatic conditions; and 4) does species diversity increase or decrease? Our study took place in 7 coastal dune forest sites of various ages regenerating after mining disturbance. We conducted tree surveys in 1999, 2001, 2005, and 2009 and herbaceous plant surveys in 1995, 1999, 2003, and 2005. We assessed trends in species turnover, composition, diversity, richness, and evenness to see if these were congruent with successional theories. Patterns in turnover for both taxa showed a decelerating decrease. Sites of a similar age shared similar species composition of coastal dune forest trees and herbaceous plants. As sites aged, they increased in the number and diversity of species. Succession-based management is a valid approach to dune forest rehabilitation as long as restoration managers recognize disturbance as an ecological reality.