Biodiversity and Conservation

, Volume 19, Issue 11, pp 3269–3285

Environmental predictors of forest expansion on open coastal barrens

Original paper

Abstract

Rock barrens support rare plant species but may be threatened by forest expansion. We determined the extent of forest expansion onto open coastal barrens and identified environmental correlates of dynamic versus persistent barrens in Nova Scotia, Canada. We used aerial photos to quantify the amount of forest expansion over the last 70 years at five coastal barrens sites and GIS to derive topographic and other environmental predictors to differentiate persistent coastal barrens compared with persistent forests or barrens that succeed to forests. Linear discriminant and classification tree analyses identified the variables associated with each class of habitat. Coastal barrens decreased by an average of 7.9% (from 4.2 to 24.6% depending on the site) in the last 70 years due to forest expansion. The best predictors of persistent barrens were elevation and distance to coast. Environmental factors such as topographical heterogeneity and evidence of fire varied among sites. Climatic and edaphic conditions near the coast and in exposed inland areas may protect coastal barrens vegetation from forest expansion. Evidence of fire was not found at all barrens sites, thus at least some of the persistent open barrens are likely maintained by shallow soils, salt spray, and wind exposure. All three classes of habitat had distinct vegetation, and the only rare species was found in a persistent barren. Management of human activities in such landscapes should take into account the dynamic nature of barrens vegetation, while prioritizing conservation efforts in persistent barrens.

Keywords

Forest succession Rock barrens Rare plants Heathland Landscape dynamics Disturbance 

Abbreviations

DEM

Digital elevation model

LDA

Linear discriminant analysis

MANOVA

Multivariate analysis of variance

CTA

Classification tree analysis

Supplementary material

10531_2010_9891_MOESM1_ESM.doc (206 kb)
Supplementary material 1 (DOC 205 kb)
10531_2010_9891_MOESM2_ESM.doc (130 kb)
Supplementary material 2 (DOC 129 kb)
10531_2010_9891_MOESM3_ESM.doc (70 kb)
Supplementary material 3 (DOC 70 kb)
10531_2010_9891_MOESM4_ESM.doc (214 kb)
Supplementary material 4 (DOC 214 kb)

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Biology Department/Environmental Studies ProgramSaint Mary’s UniversityHalifaxCanada

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