Frammentazione ambientale, connettività, reti ecologiche

Abstract
Reti ecologiche 205
Ecological networks - On the basis of an extensive background regarding this
issue, it can be pointed out that:
-the traditional focus of conservation of individual sites and species must progress
towards a more holistic, spatial concern;
-habitats must be large enough and sufficiently connected to enable the landscape
to function ecologically. Such directives have recently been stated in international
conventions, in pan-European strategies and national guidelines.
The main goals of ecological network planning are to:
- conserve the natural ecosystems, increasing the size and number of those under
protection;
- increase connectivity, taking into account species-specific differences in dispersal,
reducing isolation of habitat and fostering gene flow among fragmentation-sensitive
(sub)populations, assuring their viability;
-increase permeability of the matrix to dispersal of sensitive species;
-insert the conservation theories in the processes of landscape planning.
Aconceptual framework for planning - Planning in ecological network is a
complex exercise because of the large range of different contexts, spatial scales,
species-specific response to fragmentation, ecological and anthropic variables of
the “real world”, and no general rule can be formulated. A methodological pathway
should foresee not only the context of study but also the ecological levels, the targets
and the scales of investigation.
Scale – Connectivity is related to an appropriate scale suitable to ecology and
dynamics of sensitive (meta)populations and of those ecologically correlated.
The operative scale for ecological network strategies appears to be the landscape
one. Therefore it is advisable to apply strategies on multiple spatial scales, so covering
a large interspecific range of ecological requirements and making them
more effective.
Context – The effects of habitat fragmentation are landscape-specific, depending
on local, ecological, anthropic factors and planners have few generalizations
to help them (the “it depends” dilemma): each strategy, built for specific local pro-