Geography Reference
In-Depth Information
landscape. The R (u) (1975: 12; 2009: 10) and E (u) (1975: 0.78; 2009: 0.75) values were almost
unchanged (Table 5 and figure 15). The most important changes (Figure 14) were located in
urban areas consolidated between both dates (2009: > 30%; 1975: 15%). The surface of
mixture arborescens or shrubby woodlands with high density (
Juniperus
,
Cistus
,
Quercus
)
decreased (1975: 20%; 2009: < 10%) and were replacement with urban areas. Into
intermediate density woodlands the process is the contrary with a slight increase (2009:
30%). In this example values corresponded to disturbed areas near of urban areas or changes
in livestock production (beef cattle into extensive o semi-extensive pastoral system).
As for fragmentation, although patches number decreased in 2009, the territory was more
anthropic concentrating such growth in this sector analyzed in conjunction with the
boundary of the PNA (Table 8 and Figure 14). This produced a boundary effect preventing
the exchange of matter and energy in that direction and causing isolation of the territory
whose consequences have been already indicated by several authors: loss of diversity and of
species, less permeability, worst energy flow, etc. [62-64]. Such an example it was the large
increase of road infrastructures in 2009 more greater than 1975. This is especially significant
with N-VI, nowadays a highway that introduced fragmentation and negatives effects over
territory (Figure 14). The connectivity of the territory is also affected overtime, showing a
loss of permeability that results in a lower exchange of individuals between populations,
lower the persistence of local and regional populations, increasing the rate of extinction and
reducing the rate of colonization. Landscape connectivity favours not only movements of
animal species, but also of plant and material and energy flows [65-67]. Therefore shows a
loss of connectivity and increased fragmentation with the passage of time which is located
predominantly in the edge of the ENP. This causes a barrier effect in that direction forcing
the processes and natural movements to move into the space where connectivity is
maintained higher and less fragmentation.
Figure 13.
Single-family housing at the western edge of PNA (Torrelodones)
