Fragmentation
of forests & landscapes by roads/intersections
LB-4
Loss
of Biodiversity
Pressure
1 Indicator
definition and unit of measurement
NB:
since forests are part of landscapes this indicator has been aggregated with LB
07: Landscape fragmentation by roads/intersections. The aggregated indicator is
forest and landscape fragmentation by roads, railways, communications networks,
urbanisation & other development, etc. Unit of measurement is km per km
2
per landscape type.
2 Placement
in the framework
5EAP:
Chapter
4: Selected target sectors, section 4.4: Forestry.
Chapter
5: The themes and targets of the programme, section 5.3: Protection of nature
and bio-diversity.
Agenda
21:
Chapter
15 deals with the “Conservation of biological diversity” and calls
for action “for the conservation of ecosystems and natural
habitats” (section 15.5 g).
Chapter
10: Integrated approach to the planning and management of land resources.
International
conventions and agreements:
Habitats
Directive 92/43 (May 1992): Requirement for Appendix I habitats to be
designated as Special Areas of Conservation: including Forests.
Convention
on Biological Diversity (Rio de Janeiro, 22nd June 1992).
Rio
Declaration on Forest Principles (1992, UNCED A/CONF. 151/6/REV.1):
“non-legally binding authoritative statement of principles for a global
consensus on the management, conservation and sustainable development of all
types of forests”.
Ranking:
Core
ranking:
4
(39%)
Policy
Relevance:
7
(2.8)
Analytical
Soundness:
7
(3.0)
Responsiveness:
8
(2.6)
Most
appropriate related state indicators:
Size
distribution of forest and other land cover types in the landscape.
3 Significance
Purpose:
Fragmentation
of ecosystems has different impacts on biodiversity to habitat loss; e.g.
forest areas will be particularly prone to changes in ecosystem components such
as edges as a result of fragmentation.
Relevance:
The
indicator will contribute to the assessment of the sustainability of forest
ecosystem functions (and of the interactions between land resources and the
social, economic and environmental systems - Chapter 10, Agenda 21).
Linkages
to other pressure indicators:
LB-5:
Clearance of natural & semi-natural forest areas; LB-4: Landscape
fragmentation by roads/intersections; LB-1: Protected area loss, damage and
fragmentation.
Targets:
5EAP:
no further deterioration.
4 Methodological
description and underlying definitions
Underlying
definitions and concepts:
Forest
and landscape fragmentation can occur as a result of a number of human
activities, among them clearance, fragmentation of protected areas,
fragmentation through direct (infrastructure development) and indirect (fires,
acid rain) human activities. The indicator can be disaggregated to measure the
fragmentation caused by each sector (industry, transport etc.).
Measurement
methods:
In
the Dobris+3 exercise the European Topic Centres have prepared a
“fragmentation index” using GIS and based on digitised overlays
(including CORINE Land Cover). The main problem is the need for periodic
updating of these complex overlays.
Limitations
of the indicator:
The
impact of fragmentation on the biological integrity of any given forest or
other ecosystem will depend on the size of the remaining blocks. Any
"fragmentation index" should try to take this into account.
Alternative
definitions:
Decrease
in contiguity of the remaining blocks - e.g. a measure of the change in number
of contiguous areas per size category per forest or landscape type.
