Seedling survival patterns in Macaronesian laurel forest: a long-term study in Tenerife (Canary Islands)

摘要

Seedling dynamics of the Macaronesian laurel forest have been monitored for the first time in a long-term study to determine whether the survival of the seedling community is affected by slope aspect and forest structure. More than 4000 seedlings were monitored monthly from 2000 to 2003 in well-preserved laurel forest stands on Tenerife, Canary Islands. Trees and seedling bank species composition differed between windward and leeward slopes. On both slopes, differences in species composition between the canopy and the seedling bank suggest future shifts in canopy species composition towards a more advanced successional stage. Surprisingly, seedling survival was higher on the drier leeward than on the wetter windward slope. This seems to be related to environmental and structural differences of the forest stand between slope aspects (e.g. larger trees, higher canopy cover and tree density and lower light penetration in windward plots). Analysed species have long-lived seedling banks with survival rates of 12 per cent and 5 per cent in the long term (12 years) for leeward and windward slopes, respectively, with significant differences among species. This result reflects the high regeneration potential of the forest in well-preserved stands, indicating that no management interventions are required to ensure the regeneration of this endemic forest.