PARENT SESSION
Poster Session #71: Plant Ecology: Physiology and Function.
Friday, August 9. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC
116
Meta-analysis of the nurse effect of shrubs in reforestations in Mediterranean mountains .
Zamora, Regino*,1, Gómez, Lorena1, Gómez, Jose María1, Hódar, Jose Antonio1, Baraza, Elena1, Castro, Jorge1, 1 University of Granada, Granada, Spain
ABSTRACT- Owing to thousands of years of exploitation, most of the forests in the Mediterranean Basin have disappeared, leaving many degraded landscapes that have been recolonized by early-successional shrubby communities. Common reforestation techniques treat these shrubs as competitors against newly planted seedlings, and consequently they are cleared before planting. However, observational and experimental studies show that in Mediterranean environments shrubs have a positive effect over recruitment of many woody species. Based on these premises, we began experimental reforestations four years ago in the Sierra Nevada Protected Area (SE Spain). Our main objective was to compare the survival of seedlings planted in open areas (the current reforestation technique) with their survival when planted under the canopy of pre-existing shrubs. Between February 1997 and April 2001, a total of 20,000 seedlings of 11 trees and shrubs species were planted in 43 study areas. Zones were chosen in an effort to cover the widest array of environmental conditions (soil, altitude, aspect and slope) and species. In the present work, we report the results of a meta-analysis conducted with seedling-survival data (under shrubs and in open areas) collected from our 43 experimental field studies. The analysis concludes that facilitation between shrubs and woody seedlings, measured in terms of survival, is not restricted to a few specific species assemblages or environmental conditions, but rather has a more general pattern and thus it can be extensively applied in Mediterranean environments as a successful reforestation technique.
KEY WORDS: meta-analyisis, facilitation by shrubs, reforestation, Mediterranean ecosystems