Geoscience Reference
In-Depth Information
Conservation assessment for
alder-ash alluvial forest
Information about river habitats was based on
1:5000 scale maps that were annotated by botanical
experts interpreting aerial photographs taken in
2004 (Gobierno de Cantabria, 2004) and using
Environmental Systems Research Institute (ESRI)
ArcMap
TM
9.3.1 mapping software and map
databases. Using the aerial images vegetation types
were identified and their distribution mapped
up to 100 m on both sides of the river
channel included in the
Natura 2000
network
(Figure 16.3). This mapping exercise produced
11 337 vegetation 'polygons', with each given a
unique code. Field survey visits during 2009 and
2010 verified the mapped boundaries and also
The assessment of intrinsic and specific
characteristics (e.g. endemism, vulnerability)
determines priorities for conservation action,
while ecosystem assessment is used to identify
those factors which threaten the environmental
conditions needed to maintain species or habitats at
favourable conservation status. The core measures
selected for specific indicators were: (i) area of
habitat and distribution range of species; (ii) habitat
structure and species population composition; and
(iii) vulnerability to human activities (Figure 16.2).
The ecosystem assessment was carried out for 105
geographical units, grouped into 12 river types.
The derivation of these assessment units and river
types is described in detail elsewhere (IH Cantabria,
2010).
Fluvial network
Fluvial network mapped
kilometres
0
0.45
0.9
1.8
kilometres
0
0.2
0.4
Figure 16.3
The extent of the river network in Cantabria mapped for vegetation communities between 2009 and
2010. Habitat units were defined as 500 m river lengths and the adjacent 25 m on either side.
