Co-ordinating Editor: T. O'Connor
Release of Juniperus thurifera woodlands from herbivore-mediated arrested succession in Spain
Article first published online: 6 JUL 2009
© 2009 International Association for Vegetation Science
Applied Vegetation Science
Volume 13, Issue 1, pages 15–25, February 2010
How to Cite
DeSoto, L., Olano, J. M., Rozas, V. and De la Cruz, M. (2010), Release of Juniperus thurifera woodlands from herbivore-mediated arrested succession in Spain. Applied Vegetation Science, 13: 15–25. doi: 10.1111/j.1654-109X.2009.01045.x
- Issue published online: 12 JAN 2010
- Article first published online: 6 JUL 2009
- Received 9 January 2009;Accepted 2 June 2009.
- climate response;
- land-use history;
- livestock browsing;
- spatial pattern
Question: Do abiotic constraints maintain monospecific woodlands of Juniperus thurifera? What is the role of biotic (livestock) versus abiotic (climate) drivers in the recruitment and growth of the different tree species?
Location: Cabrejas range, Soria, north-central Spain, 1200 m altitude.
Methods: Stand history was reconstructed using dendro-ecology and spatial pattern analysis, combined with historical data of livestock abundances and climatic records.
Results: J. thurifera establishment occurred in two distinct pulses, with a tree component establishing in the late 1800s to early 1900s. Quercus ilex and Pinus sylvestris establishment was evident only from the late 1970s onward. Recruitment events were related to reductions in livestock browsing. J. thurifera spatial structure was clumped and Q. ilex showed a short-scale aggregation to J. thurifera trees and saplings. Radial growth trends of J. thurifera saplings, Q. ilex and P. sylvestris were negatively related to livestock density. Summer drought limited the radial growth of all the study species, and P. sylvestris and Q. ilex grew faster than J. thurifera even after considering an age effect.
Conclusions: The differences in radial growth patterns and recruitment pulses between species indicate that livestock browsing and not abiotic factors is the main factor controlling plant succession and structural development. In this process, J. thurifera acts as a nurse plant, facilitating the establishment of other tree species. Under the current low pressure from herbivores, formerly pure J. thurifera woodlands will change towards dense stands of mixed species composition.