The significance of fire intensity in creating local patchiness in the Chilean matorral

The hypothesis that high and low intensity human-made fires can produce ecologically different effects in the Chilean matorral is examined. We compared the abundance of naturally established seedlings under shrubs burned by low and high intensity fires on five north and five south facing slopes. On south facing slopes, we found 54 shrubs burned by low intensity fires and only 4 shrubs burned by high intensity fires. In contrast, north facing slopes had approximately the same number of shrubs burned by low and high fire intensity fires (24 versus 19, respectively). We only found seedlings under shrubs burned by low intensity fires and most of them were of Muehlenbeckia hastulata and Trevoa trinervis. Also viable seeds were only found under shrubs burned by low intensity fires. Results indicate that fire intensity can be an important factor determining species distribution patterns in the matorral.