Transcript Why are cultural landscapes rich in different conservation values in rich

Why are cultural landscapes rich in
species and why do they have
different conservation values in rich
and poor countries?
OLE R. VETAAS
UNIFOB-Global, University of Bergen,
Nygaardsgaten 5, N-5015 Bergen, Norway.
E-mail: [email protected]
The European
Union uses large
sums to
conserve human
modified
grasslands and
forest
Calluna heath
needs to be protected
Cultural
landscapes
made by
grazing of
large
mammals
Conservation paradox
• In the 3. world tropics and subtropics, on the other hand
utilized forest and grasslands are viewed as degraded
landscapes far removed from the wilderness that
Westerners want to experience in this part of the world.
Difference in biology between the
rich and poor countries ?!
• The main cause of these discrepancies is
that conservation is not based on science
but is a policy-driven top-down process
Ecological Theory indicate that
use and conservation is possible
• Ecological theory show
• possible to combine use and conservation,
and this may enhance species richness
• but there is as yet a lack of science-based
conservation and evidence-based
management of protected areas.
Why are cultural landscapes rich in species?
• (I) Succession theory
(Odum 1969)
• (II) Theory on the relationship between
herbaceous species richness and biomass
(Grimes 1973a)
• (III) Intermediate disturbance hypothesis
(Hutchnison 1951, Grime 1973b, Connell 1978)
•
(IV) Theories of relative species abundance
(Raunkiær 1920, Preston 1962, Hubbell 2001)
Theory (I)
• Succession theory
• biomass increases with time,
• NPP increases with time, but levels off or
declines in the mature phase with maximum
biomass
• species richness is highest in the phase before
the mature vegetation is developed.
• NPP= net primary production
Secondary Succession
and species richness
Species richness
biomass
Mature pine-oak forest
Young forest species
Annual
weeds
Perennial
weeds and
grasses
Shrubs
time
T
Biodiversity: succession
Species richness
Number of species
per unit area
Successional time
Theory II
• Grimes (1973a) theory on the relationship
between herbaceous species richness and
biomass
• Most species richness at an intermediate
amount of biomass e.g. 500 g on 1 square
metre
• (al-Mufthi 1974)
Biodiversity and biomass
species richness
Increasing biomass; g/m2
Theory III
Intermediate disturbance hypothesis
• Hutchnison (1951), Grime (1973b), and
Connell (1978), has suggested that there
is higher chance for many species to
coexist, when a community or landscape
is moderately disturbed.
• This tenet is well accepted, although
disturbance is difficult to define and
measure
Biodiversity and disturbance
species richness
Increasing disturbance
Disturbance definition
• Many different definitions
• Grime: disturbance = reduced or
destructed biomass
• Browsing, Grazing, Fire or other
biomass outtake are regarded as
disturbance
Biodiversity;
biomass and disturbance
species richness
increasing biomass
increasing disturbance
Change in biomass, net and
gross primary production
GROSS PRIMARY PRODUCTION
BIOMASS
NET PRIMARY PRODUCTION
RESPIRATION
TIME
Theory IV: relative species abundance
• It is very rare to be common,
• and it is very common to be rare
• There are many infrequent species and
very few frequent species (dominats)
Many infrequent species
and few common species
Raunkiær frequency diagram
Number of species in each class
Frequency classes
A= 1 – 20 %
A
B= 21 – 40 %
C= 41 – 60 %
D = 61 – 80 %
B
E = 81 – 100 %
E
C
D
Frequency classes
Based on these tenets one may infer that if the dominant
species in a plant community is harvested one may
actually increase the local plant species richness.
Species richness
biomass
Mature pine-oak forest
Young forest species
Annual
weeds
Perennial
weeds and
grasses
Shrubs
time
T
SYNTHESIS
• Most species at intermediate biomass and disturbance, and in
the intermediates to later phases of the succession.
• Disturbance is the same as reversing succession.
• There are in general many infrequent species and a few
species that are dominant in most landscapes types or
ecosystems.
• The infrequent species constitute the bulk of the total diversity,
whereas the dominant species may have strong feedback on
the vegetation.
• Based on these tenets one may infer that if the dominant
species in a plant community is harvested (i.e. disturbance)
one may actually increase the local plant species richness.
Exploit the dominant species
•
•
•
•
This may be done by:
Lopping or pollarding of canopy trees
Browsing by large mammals
FIRE
Conservation challenge in a rural areas
in a poor Third world countries
• National parks was first developed in western
developed countries.
• Population growth is stable and rural poverty is
almost absent.
• Developing countries have large rural populations
and subsistence economies
• Thus the classical concept of national parks creates
conflict with the local people
• Protected area needs to allow human populations to
live within it and provide some economic benefits for
them as well as achieving its conservation goals
Increasing lopping
Species richness in utilized oak forest
Fire Controls the secondary
succession
Lack of fire and browsing
landscape return to forest
DOMESTIC
ANIMALS
GRAZING
Cultural landscapes protection
• Human utilization of biomass within a protected area
• Changed the concept of conservation, from the
naturalistic “wilderness” to the cultural landscape.
•
• The cultural landscape, e.g. traditional managed
pastures and human modified forest, have high
biodiversity and can in addition be used for recreation
• However, science based management is prerequisite to
keep the cultural landscapes in state that both serve the
people and the biodiversity preservation goals
The human touch…
Nature in Northern Europe (Nordic Council of Ministers, Nord 2001)
Increasing lopping
Change in biomass, net and
gross primary production
Secondary succession
GROSS PRIMARY PRODUCTION
BIOMASS
NET PRIMARY PRODUCTION
RESPIRATION
TIME