Vol. 32 – 2006 - Ecologia Mediterranea

occur from small subpopulations rather than
in the opposite direction (Serrano & Tella
2003), the risk of extinction for the smaller
colonies is further exacerbated by the negative
migration balance. The fact that the
boundaries of the National Park of Alta Murgia
do not include nearly 50% of the steppe
areas of the identified Priority Zone, especially
around the smaller colonies, calls for
particular attention.
This study highlights a different situation
from the ones observed in other geographical
contexts characterized by distinct landscape
structures (e.g. Bustamante 1997; Parr et al.
1997; etc.). In south Portugal, the colonies are
associated with uninhabited buildings, and the
lesser kestrels avoid human settlements,
remaining closer to their nest sites (Franco &
Sutherland 2004). In central Turkey, the percentage
of steppe-grasslands within 1-2 km of
the nest site is associated significantly with
colony size (Parr et al. 1997). In the Murge
district, the lesser kestrel shows a different
behaviour and, consequently, specific priorities
arise. Conservation efforts and economic
resources should focus on three main aspects.
First, the park boundaries (i.e. the legislative
ecologia mediterranea – Vol. 32 – 2006
Priority Zones for Mediterranean protected agro sylvo pastoral landscapes
Tableau 2 – Results of regression analyses (explanatory variables: x 2 , x 3 or x 23 ) for the categories barren steppe (B-steppe),
barren plus shrub steppe (BS-steppe) and total steppe cover (T-steppe).
Steppe type variab. r2 F p coeff. S.D. t p confidence limits
(95%)
B-steppe x2 0.85 34.7 0.001 intercept 1.68 0.17 10.1 0.000 1.27 2.09
x2 0.49 0.08 5.9 0.001 0.29 0.69
x3 0.64 10.6 0.018 intercept 1.44 0.36 4.0 0.007 0.56 2.33
x3 0.49 0.15 3.3 0.018 0.12 0.86
x23 0.71 15.0 0.008 intercept 1.28 0.34 3.7 0.010 0.44 2.12
x23 0.52 0.14 3.9 0.008 0.19 0.86
BS-steppe x2 0.80 24.2 0.003 intercept 1.44 0.24 6.0 0.001 0.85 2.04
x2 0.55 0.11 4.9 0.003 0.28 0.83
x3 0.63 10.4 0.018 intercept 1.43 0.37 3.9 0.008 0.53 2.33
x3 0.47 0.15 3.2 0.018 0.11 0.83
x23 0.74 17.4 0.006 intercept 0.99 0.39 2.6 0.044 0.04 1.93
x23 0.61 0.15 4.2 0.006 0.25 0.96
T-steppe x2 0.72 15.6 0.008 intercept 0.73 0.47 1.6 0.173 – 0.43 1.88
x2 0.79 0.2 4.0 0.008 0.30 1.28
x3 0.71 14.6 0.009 intercept 0.35 0.59 0.6 0.577 – 1.09 1.78
x3 0.85 0.22 3.8 0.009 0.30 1.39
x23 0.73 16.0 0.007 intercept 0.15 0.61 0.3 0.808 – 1.33 1.64
x23 0.86 0.21 4.0 0.007 0.33 1.38
measures) should better encompass the Priority
Zones, at least where they overlap the barren-steppe
range. Clearly, if these areas were
fully included within the parks, they would be
specifically protected by laws limiting inappropriate
human activities.
Second, the management of the Priority
Zones should concentrate on the conservation
of B-steppe. Phytohistorical studies have
documented the fact that grazing activities
(mainly extensive sheep pastures) have been
ongoing for thousands of years, since the pre-
Roman age (Amico 1954). The management
of domestic-herbivore grazing has been recognized
as an important conservation strategy
because its intensity and frequency can affect
habitat structure and biodiversity (Noy-Meir
et al. 1989; Bignal & McCracken 1996; Noy-
Meir 1998; Watkinson & Ormerod 2001;
Labaune & Magnin 2002; Verdù et al. 2000;
Verdù & Galante 2002). Our results show the
pivotal role of barren steppe, suggesting that
grazing activities should be managed to
favour this vegetation-structure type. On the
other hand, several studies have demonstrated
how landscape heterogeneity (that is a mosaic
of open grassland, shrub steppe and steppe
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