National programme for Populus nigra conservation Marc Villar, coord. EUFORGEN Network for Populus nigra & P. alba Sven de Vries, chair Davorin Kajba, vice-chair >20 countries involved Strategies and methodologies for the in situ genetic conservation of Populus nigra, an example of CWR in forestry François Lefèvre, INRA Avignon (France)

integrated approach to the conservation of genetic resources general strategy for in situ conservation of P. nigra from research results to practical recommendations

domestic resource wild relative interactions Integrated approach to genetic resources Population management Indirect human impact Habitat monitoring (pop. management) environnement landscape general model

domestic resource ex: cattle Population management Indirect human impact Integrated approach to genetic resources

domestic resource wild relative interactions Integrated approach to genetic resources Population management Indirect human impact Habitat monitoring (pop. management) ex: most of the crops

domestic resource wild relative interactions Integrated approach to genetic resources Population management Indirect human impact Habitat monitoring (pop. management) ex: some trees (poplar), fishes (truit)

domestic resource wild relative interactions Integrated approach to genetic resources Population management Indirect human impact Habitat monitoring (pop. management) ex: some trees (oak), animals (game)

wild species Integrated approach to genetic resources Indirect human impact Habitat monitoring (pop. management) ex: wild species with economic value

Interactions: - gene flow - pathogenes - habitat availability Populus nigra

regeneration reproductive trees pre- mature trees oldest trees strictly pioneer metapopulation dynamics Populus nigra poplar demography is affected by the management of rivers in Europe

Inventory: no information from foresters => National Nature Reserves Pont et al., 2000 Populus nigra absence (70) présence (29) suitable habitats for the dynamics of P. nigra rare, and generally found out of its optimal habitats

EUFORGEN Network Objectives of in situ conservation: 1. ensure the regeneration in sufficient quantity 2. ensure the genetic quality of the regeneration 3. preserve the ecological and genetic characteristics In situ conservation of Populus nigra

population size & ecological conditions Natural in situ Managed in situ Restoration project Temporary in situ P. Rotach conservation units In situ conservation of Populus nigra

ecosystem & poplar biology N. Barsoum In situ conservation of Populus nigra

B. Heinze, F. Lefèvre restoration projects actively plant P. nigra where ? - suitable sites (river flooding regime,...) how ? - suitable techniques specific for P. nigra what ? - suitable sources of plant material "restoration genetics" how many individuals - Ne equivalent restoration management how to maintain viable populations in the long term In situ conservation of Populus nigra

ecological indicators hydroperiod, area pioneer vs. mature stage & tendancy, … demographic indicators occurrence of regeneration, nb of adult trees, sex ratio, … genetic indicators genic diversity, differenciation among cohorts, introgression… => inform on the processes of evolution stochasticity, drift, mating system, gene flow, selection monitoring the genetic diversity F. Lefèvre, D. Kajba In situ conservation of Populus nigra

N. alba In situ conservation of Populus nigra inventory of stands Database specifically developed for P. nigra conservation “passport” data code, location, river, tributary, protection status, … demography of current population occurrence of regeneration, nb of adult trees, sex ratio, … ecology & current management soil, climate, hydroperiod, river and forest management,...

From research to recommendations EUROPOP (B.C. van Dam coord) gene flow (seed & pollen) mating system clonal propagation introgression ongoing processes of evolution

The genetic diversity is not evenly distributed: differentiation among populations within each country differentiation among populations within river-system no accumulation of diversity down the rivers variable amount of diversity among populations variable amount of clonal redundancy From research to recommendations research results 1. conservation sites

From research to recommendations recommendations should be distributed over the range of the species map of cpDNA lineages ecological conditions (altitude, latitude) eventually more than 1 site per river-system preliminar estimate of the genetic diversity among adult trees 1. conservation sites

From research to recommendations research results 2. introgression Gene flow with cultivated poplars is scarce but not null: P. deltoides genes are sometimes detected at seedling stage especially on isolated P. nigra female older introgressed individuals are rare over Europe P. trichocarpa genes can also introgress P. nigra P. nigra ‘italica’ cannot hybridise local resource in Northern Europe, but can in other regions

From research to recommendations 2. introgression recommendations no need to completely forbid all poplar plantations around the conservation units estimate the amount of introgression for adult trees only further check introgression from P. trichocarpa pay attention to ‘italica’ only in Southern Europe and if the number of local pollinators is limited

From research to recommendations research results 3. population size Mating does not occur at random: female trees preferentially mate to few particular males (distance, phenology) half-sib progenies from a single mother tree only involve few pollinators Gene flow follows the model of isolation by distance: effective gene flow  potential gene flow seedling establishment is a limiting factor gene flow is symmetrical, wind dispersal pollen and seeds

From research to recommendations 3. population size recommendations number and spatial distribution of females is critical effective population size requires a balanced sex ratio seed-set and seedling establishment should be favoured to restore populations, unrelated clones should be preferred to seed progenies assisted regeneration should be achieved on several scattered plots rather than a single large one rely only on poplars located 5 kms apart to contribute significantly to the population size

From research to recommendations research results 4. monitoring local evolution Drift effects are observed at local scale (within stand ): differentiation among cohorts differentiation among seedling patches it can affect the fitness of the populations

From research to recommendations recommendations 4. monitoring local evolution focus attention on all practices that have an impact on: the flowering habit the regeneration process ecological and demographic indicators most relevant: hydroperiod structure of habitats nb. and distribution of male & female trees

genetic diversity highlow low high migration load local pop. large Ne genetic diversity highlow low high local pop. small Ne Large amount of transplanted material involved in the regeneration

Wild Cultivated Host Populus nigra hybrids diverse populations monoclonal stands general R race-specific R Parasite* few virulences* complex races ? co-evolutionselection gene flow pathogen flow (Pinon et al., 1995)