Fire in the Mediterranean Basin - Fire in Mediterranean Ecosystems - page 87

(Turner et al. 2008 ; Linsta ¨ dter & Zielhofer 2010 ), and with a moist period in wetter
areas, suggesting fuel moisture limitations (Carrio´ n 2002 ; Sadori & Giardini 2007 ).
The consequence of the long human pressure on this landscape is that little if
any of the landscape has escaped human impacts and most landscapes are very far
from their natural state. This fact has important implications for fire ecology and
management, as well as restoration ecology, in particular the lack of a reference
ecosystem (Vallejo et al. 2006 ).
Recent Socio-economic, Land Use and Fire Changes
The longest available fire history for a Mediterranean Basin site (130 yrs) suggests
that there has been a relatively recent shift in fire regime. This was related to
socio-economic changes in the 1970s and resulted in an increase in the frequency
of large fires (Pausas & Ferna´ ndez-Mun˜ oz 2011 ). This shift is specially observed
in the northern rim (European) countries where with industrialization came
rural depopulation, abandonment of farmland and a reduction in the livestock
grazing pressure (without replacement by natural grazers). This process resulted in
increases in the amount of fuel, especially in early succession species (many of
which are very flammable, Baeza et al. 2011), and changes in the landscape pattern
and the fire regime (Moreira et al. 2001 ; Lloret et al. 2002 ; Pausas 2004 ; Bajocco
et al. 2010 ; Pausas & Ferna´ ndez-Mun ˜ oz, 2011 ). Furthermore, many of these old-
fields have been extensively planted with pines and Eucalyptus during the last few
decades (Pausas et al. 2004a , 2008 ), resulting in even higher fuel loads and fuel
continuity. Thus, at present, the main ecological process occurring in the
Mediterranean, especially on its northern rim, is land abandonment and its impact
on fire ( Fig. 4.2 ).
At the same time increased development along coastal areas as a result of both
the escalating tourism pressure (holiday resorts and retirement homes) and life
style changes (houses instead of flats) has had indirect effects on ecological
processes and fire regimes. The spread of new urban and semi-urban populations
in rural areas is covering many old-field areas. The consequences of these trends
are mainly (1) an increase in water demand due to the reduction of aquifers, (2)
habitat fragmentation and (3) an increasing wildland-urban interface, which
contributes to increased fire ignitions.
All of these processes are important drivers behind the increase in number of
wildfires and area burned in recent decades. In fact, the number of ignitions
increased (exponentially) from the 1960s to the 1980s in most countries ( Fig.
4.3 ), and there is a correlation between population density and fire ignitions
(Terradas et al. 1998 ; Catry et al. 2009 ). The area burned also increased exponen-
tially on the northern rim of the Mediterranean Basin during this period (Pausas
2004 ; Fig. 4.4 ). However, the influence of climatic changes cannot be denied (Pin ˜ ol
et al. 1998 ; Pausas 2004 ). In fact, fire and climate are strongly correlated during
recent decades, but not for the period previous to the fire regime shift of the 1970s