Genetic implications of forest management in the Mediterranean

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


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


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)


Genetic system of a forest population H

atte

mer &

Gille

t 2000


Generations of forest trees


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


Genetic diversity of forest species

Petit et al. 2003


Reasons for high diversity

• The relief of the Mediterranean basin


Reasons for high diversity

• The Mediterranean

climate

• The existence of

tectonic microplates

and their move


Reasons of high diversity

• The glaciations era – refugia


Human and forests

• Most ancient human cultures

• Centre of the “known world”

• Organized trade and land use

• First “globalized” economies


Direct use of plant species


Human shaping nature

Agriculture, grazing,

fuelwood collection, etc.

shape the landscape…


“Mosaic” - forest landscape


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


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)


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


Genetic bottleneck

0

200

400

600

800

1000

1200

1400

CRASH

Bottleneck

RECOVERY

TIME

N


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


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)


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


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


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)


Example: Abies cephalonica

• Higher values of inbreeding levels in uneven

aged forests with lower population densities

Fady & Conkle 1993


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


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


Forest management


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


Protection of forest biodiversity

SFM as a tool to achieve biodiversity conservation

Protects BD elements, including genes & provenances


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


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)


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”)


• 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


• 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


The challenge


• 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


• 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


• 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


Thank you for your attention

Genetic implications of forest management in the Mediterranean

Education

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