The effect of porcupine and bast scale on Aleppo pine recruitment after fire

摘要

The combined effect bar of a large-scale fire followed by small-scale herbivory by porcupines and bast scales were studied on the recruitment of Aleppo pines (Pinus halepensis). A massive fire on Mount Carmel, Israel, in 1989 destroyed 300 ha of a natural pine forest. Although Aleppo pine is fire-adapted, its resilience after fire is jeopardized by other biotic and abiotic hazards. Herbivory by porcupine and scale was responsible for the loss of approximately 6.5% of the saplings at four years post-lire. Porcupine damage was patchy but rather heavy (mean =15% mortality of pine saplings with a maxium value of 21% mortaiity) in plots with low vegetation cover and high rock cover while only marginal impact was observed in relatively dense vegetation (mean mortality = 0.5%). Similarly, scale damage was widespread patchy (with maximum of 37% sapling mortality), and not correlated with vegetation cover. While porcupine activity emerged only in the fourth year after the fire, scales infested saplings over a wide range of ages. Porcupine activity was local and distributed over relatively small areas while scale infestation was widespread and general. This study demonstrated that post-fire pine sapiings in harsh condition patches (shallow dry soil, high rock cover) are more exposed to the combined damaging effect of porcupine and scales than sapling in patches with more suitable environmental conditions.