Agriculture Reference
In-Depth Information
Conclusions
The most striking difference between the Mediterranean Basin and the other MTC
regions is its substantially longer history of intensive and widespread land use.
Little of this landscape has escaped human impacts and this has implications for
fire ecology and management. An appropriate metaphor is that of a palimpsest,
where modern plant communities are overlaid on landscapes still containing
markings of earlier uses. All evergreen shrub species are obligate postfire resprou-
ters and a few have well-developed lignotubers. Resprouting success is very high
and maquis shrublands regenerate rapidly after fire. Thus, the small postfire gaps
have selected against postfire seeders, which are less common in maquis shrub-
lands. These obligate resprouting shrubs and small trees avoid the stressful
summer drought by means of deep roots and thus seedlings are dependent on
finding favorable mesic microsites. This is enhanced by production of fleshy,
vertebrate-dispersed fruits with long-distance dispersal. On more arid sites
shorter-lived semi-deciduous shrubs or subshrubs exhibit a very different fire
response in that most have specialized reproduction by delaying it until the post-
fire environment. Many leaf and stem traits of species on these sites contribute to
making these communities highly flammable. Site aridity coupled with a high
frequency of high-intensity fires contribute to the abundance of postfire gaps
and selection for postfire seeders. The majority of communities are crown fire
ecosystems although a few montane pines historically burned in surface fire
regimes. Land use changes during the latter quarter of the twentieth century have
resulted in a shift in fire regime. This is due to rural depopulation, abandonment
of farmland and recolonization of sites by woody species that greatly add to the
fuel load and increase the size and intensity of wildfires. This coupled with urban
expansion is creating a wildland-urban interface fire problem not previously seen
in this region.
