Genetic Implications of
Forest Management
in the Mediterranean
Solsona 2004
Aristotelis C. Papageorgiou
Department of Forestry, Environment and Natural Resources,
Democritus University of Thrace, Greece
April 4, 2004 MEDFOREX meeting 2
Presentation plan
• Genetic diversity in Mediterranean forests
• Factors influencing genetic diversity
• Impact of forest management
• SFM and genetic diversity
• Research and policy priorities
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What is so special about the Med?
• Biological, cultural, social, historical diversity
• Biological diversity:
– rich mosaic of changing ecosystems and land use
patterns (from alpine to tropical)
– Large amount of species (especially plants) – high
endemism
– Populations of species with a broader distribution
are the most variable in terms of genetic diversity
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Genetic diversity
• Differentiation among individuals and groups of individuals (populations) exists.
• Differentiation at the gene level can be inherited = genetic variation
• Key for adaptation in changing environments over space and time
• Connection between generations
• Is usually measured in traits that are not important for forestry (e.g. DNA markers)
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Genetic system of a forest population H
atte
mer &
Gille
t 2000
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Generations of forest trees
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Genetics of Mediterranean forests
• Disjunct distribution of populations and species –
high differentiation
• Usually high genetic variation within populations –
comparison with N/C Europe
• Many small populations
• Large distributions of species over different
environments (e.g. Pinus species)
• Unique alleles and races
• Paradox of variation in several cases
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Genetic diversity of forest species
Petit et al. 2003
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Reasons for high diversity
• The relief of the Mediterranean basin
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Reasons for high diversity
• The Mediterranean
climate
• The existence of
tectonic microplates
and their move
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Reasons of high diversity
• The glaciations era – refugia
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Human and forests
• Most ancient human cultures
• Centre of the “known world”
• Organized trade and land use
• First “globalized” economies
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Direct use of plant species
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Direct use of plant species
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Human shaping nature
Agriculture, grazing,
fuelwood collection, etc.
shape the landscape…
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“Mosaic” - forest landscape
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Mediterranean forests
• Forest includes terrestrial ecosystems in a broad sense
• Natural forest ecosystems – mixed forests – complex age
structures – connection between generations
• Mainly small scale activities – high land use diversity –
fragmentation – mixed with other activities
• Degradation – desertification – loss of ecosystem
productivity – land abandonment
• High protective role against erosion, drought – social
importance for rural development
• Recreation – quality of life – Non Wood Goods
• Culture – spirituality
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Human impact on gene diversity
• Far-reaching / global
– Emission of air pollutants
– Greenhouse gases
– Policy processes
• Local
– Forest destruction (land conversion)
– Forest fragmentation
– Forest management • Introduction of new species & populations
• Silvicultural activities
• Other forms on management (e.g. grazing)
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Destruction and fragmentation
• Forest destruction (deforestation)
– Loss of species with small scale (e.g. Abies nebrodensis, Quercus euboica, Cedrus brevifolia)
– Loss of populations (differentiated – adapted)
• Forest fragmentation
– Reduction of effective population size – drift effects – genetic bottlenecks
– Increase vulnerability of populations
– Caused by development, agriculture, grazing
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Genetic bottleneck
0
200
400
600
800
1000
1200
1400
CRASH
Bottleneck
RECOVERY
TIME
N
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Example: Pinus leucodermis in Italy
• Only a few small
populations
remaining –
fragmented – no
connection possible
• Low genetic variation
– large differentiation
among populations
Morgante & Vendramin 1991
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Artificial regeneration
• Adaptation on the final site in question
– Different adaptations at the original site
– Adaptation in nurseries
• Genetic variation (evolutionary adaptability) reduced due to drift effects
– Harvest from small number of plants (founder)
– Unknown material – provenance ignored
• Possible impact on surrounding forests due to gene flow
• However: development of new land races (e.g. Quercus rubra in France)
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Example: Cupressus sempervirens
• Low genetic variation
of planted stands
• Canker attack in
planted stands
• Gene flow from
planted stands in
natural populations
Papageorgiou et al. 1994
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Natural regeneration
• Connection between generations - maintenance of dynamics of genetic structures in life cycle of forest trees – evolution goes on
• How many individuals participate in the next generation? Where? – Natural processes (very improbable in the Med)
– Non-forestry activities (e.g. grazing)
– Forestry operations (e.g. light felling)
• Limited potential for changes of genetic structures – No safeguard against unintentional & random changes of
genetic structures, losses of genetic variation
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Silvicultural treatments
• Low population densities
• Reduced gene flow – Possible founder effects (a few seeder trees)
– Increased inbreeding – low germinability
– Inbreeding depression
• Threshold values for – Population sizes
– Population densities
• Problem for scattered species – Particularly in species-rich mixed forests
– Species with “peculiar” mating system (Taxus baccata)
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Example: Abies cephalonica
• Higher values of inbreeding levels in uneven
aged forests with lower population densities
Fady & Conkle 1993
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Selective cutting
• Selection against superior phenotypes
– Selective logging with short cutting cycles
– Exclusion of superior phenotypes from reproduction
• Reduction of mating trees
– effective population size
– Inbreeding
• Coppice forests
– Clear cuts with a few remaining trees
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Is genetic diversity at stake?
• Disturbance of human – nature balance
• The dynamic systems are broken (genetic, ecological,
nutrients, water, energy, etc.)
• Ecosystem are not able to provide goods and services in the
long term – desertification.
• Main problems occur mainly from factors outside SFM
• The maintenance / restoration of the ability of
Mediterranean ecosystems to continue their
dynamic function should become the target of
any conservation effort in the region
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Forest management
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Forest management in the Med
• Management strategies & techniques imported from the central and northern counties of Europe - production of timber is priority in most cases
• Apply on the more temperate forests of the Mediterranean region - ignore the non-productive terrestrial ecosystems (e.g. maquis)
• Fail to capture the complexity of Mediterranean forests & land use systems
• The spatial reference of SFM is the stand and not the broader landscape - more appropriate for the description of the human - nature dynamics
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Protection of forest biodiversity
SFM as a tool to achieve biodiversity conservation
Protects BD elements, including genes & provenances
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Forest protection in the Med
• Protection concepts and strategies imported from northern counties with empty spaces and productive forests - human influence on BD is ignored
• Based mainly on the “set – aside” principle
• Focus on absolute protection or special management of specific biological entities (e.g. genes) or spatial units – miss the broader picture
• Restricted to reserves and networks
• Selection of protected items – majority remains unprotected
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Forest conservation genetics
• Forest genetic resources
– Included in broader BD policies & plans
– Most under-represented part of BD
– Based in “genetic inventories” (assessments)
• In situ
– Actions of strict protection of rare or endangered entities
– Gene reserves (special management allowed)
– Conservation in managed ecosystems (Namkoong).
• Ex situ
– Protection of endangered or rare tree species
– Storage of “useful” genes (gene banks)
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An important gap
• “Other wooded land” – not protected, not managed
• The classical protection / SFM approach
– has a spatial gap of about 50%
– cannot cope with the dynamic nature of Mediterranean forests
• Conservation of forest genetic diversity cannot be seen separately from the general use and management of forest resources
• Inventories possible in a few cases only (no time, no money for “total inventories”)
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• Environmental agencies consider BD as a priority in all management activities
• Forestry parties see the economic aspect of forestry as a priority.
• BD conservation and SFM can be linked:
– Complexity of both concepts
– Long term character
• “Ecosystem approach” & “close to nature” forestry
• Tools, such as SFM certification, “criteria & indicators”, Special Management plans, NFP
Linking SFM and BD
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• Maintaining adequate levels of genetic diversity of tree (& other) species is crucial for adaptation and adaptability processes
• Dynamic processes must maintain their role for the maintenance of productivity of goods and services
• Genetic diversity is not just another goal of SFM, but the means to achieve it
• We need: Management techniques that will prevent disturbances in critical ecological and genetic processes
The challenge
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The challenge
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• Develop inventory systems for genetic diversity status of terrestrial ecosystems (stand types)
– Use results of existing genetic research projects
– Plan future genetic research
– Use models to simulate evolution under forest management scenarios
– Connect gene diversity with stand & age structure, density, mating system, etc.
• Develop criteria & indicators for genetic diversity
– adjust existing efforts to the Mediterranean
– introduce genetic criteria into existing SFM C&Is (certification standards, MCPFE criteria, etc.)
Future research priorities
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• Connect specific management techniques of Mediterranean forests with the previous steps
– Give a “genetic grade” for each technique
– Evaluate human impact on genetic diversity
• Set priorities for SFM considering genetic diversity
• Extrapolate of appropriate strategies for most taxa from the results of studies of a few model cases
• Identify genetic aspects that may become limiting for certain types of species and ecosystems
• Monitoring and evaluation
Future research priorities
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• Develop management plans for the
Mediterranean beyond the classical forestry
approach, including broader ecosystems and
activities, based on the maintenance of
genetic diversity
• Protecting biodiversity through management
and planning, following rules that need minor
assessments
SFM for the Med
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Thank you for your attention