HR: 09:15h
AN: H51M-06    [Abstracts]
TI: The Effects of Repeated Fires on Vegetation Communities Structure and Implications for Geomorphological Processes
AU: * Malkinson, D
EM: dmalk@geo.haifa.ac.il
AF: Dept. of Geograpy and Environmental Studies University of Haifa, Mount Carmel, Haifa, 31905, Israel
AU: Beeri, O
EM: beeri@aero.und.edu
AF: Department of Space Studies, University of North Dakota, University Ave and Tulane St., Grand Forks, ND 58202, United States
AU: Wittenberg, L
EM: leaw@geo.haifa.ac.il
AF: Dept. of Geograpy and Environmental Studies University of Haifa, Mount Carmel, Haifa, 31905, Israel
AB: Forestfires have been recognized to be an inherent component of Mediterranean ecosystems. It has been suggested that fires have been human induced for eons as a management practice in the eastern part of the Mediterranean Basin. By the beginning of the 20th century, however, most of the open space in the nowadays region of Israel were denuded of vegetation. During the 1920's and through the 1950's major afforestation efforts took place in the region. Evidence suggests that in the Mediterranean Basin, as well as in Israel, the number of wildfires has increased dramatically over the last several decades, due to human activities. We propose, however, that the areas consumed by the fires increased as a result from the maturation of the maquis and forested regions. The Carmel Ridge in Israel is taken as a case study, where we use satellite image analysis to monitor vegetation changes in areas repeatedly burned during the last 22 years. An extended vegetation study of the region was conducted during 1985, and serves as a baseline for the state of the vegetation. Satellite images from 1990 (following a 1989 fire), 1995, 2000 (following 1998, 1999 fires) and 2006 (following a 2005 fire) were used to classify the different vegetation classes for each year, based on spectral and derived vegetation indices. The resulted classifications revealed changes in the spatial distribution of pine, broad-leaves and shrubby vegetation classes. Transition probabilities among the vegetation communities are being used to construct a Markov based transition matrix, which also accounts for aspect dependent vegetation dynamics (north VS. south facing slopes). In turn, a simulation model is being used to assess the effects of different fire regimes on long term vegetation changes. Preliminary results suggest that recurring fires within short time intervals may significantly alter the long-term structure of the vegetation communities. The pine stands may be replaced by a mixed maquis-shrub community, as pine stands do not have a sufficient time to develop a large enough of a seed base, following the frequent fires. These long-term changes may have implications for geomorphological processes, including the hydrological system and soil loss.
DE: 1640 Remote sensing (1855)
DE: 1803 Anthropogenic effects (4802, 4902)
DE: 1847 Modeling
DE: 1851 Plant ecology (0476)
SC: Hydrology [H]
MN: 2007 Fall Meeting