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Scaling Mediterranean biodiversity in space and time
Jacques Blondel
CNRS
Drivers of biodiversity: downscaling from global to local
Global, northern hemisphere: macrogeographical processes
Regional, Mediterranean: Plio-Pleistocene history
Local : environmental gradients
Landscape: local disturbance regime (moving mosaic)
Habitat: structure and dynamics
Drivers of biodiversity: downscaling from global to local
Global, northern hemisphere: macrogeographical processes
Regional (Mediterranean): Plio-Pleistocene history
Local : environmental gradients
Landscape: local disturbance regime (moving mosaic)
Habitat: structure and dynamics
Introduction
1.1*106 km² 1.2*106 km²
1.2*106 km²
The history of forest biotas in the Northern Hemisphere
Introduction
Trees: 253 Birds: 725
Trees: 729 Birds: 1000
Trees: 124 Birds: 500
Geographical constraints: limits to dispersal
Introduction
Number of tree taxa in the three regions of the N.H. East. Nearctic West. Palearctic East. Palearctic
157 106 876 Genus East. Nearct. West. Pal. East. Pal.
Acer 10 9 66Alnus 5 4 14Betula 6 4 36Ulmus 4 3 30Magnolia 8 0 50Quercus 37 18 66Tilia 4 3 20
Latham & Ricklefs, 1993
Drivers of biodiversity: downscaling from global to local
Global, northern hemisphere: macrogeographical processes
Regional (Mediterranean): Plio-Pleistocene history
Local : environmental gradients
Landscape: local disturbance regime (moving mosaic)
Habitat: structure and dynamics
Zonation of vegetation assemblages in the Mediterranean
Quézel & Médail, 2003
Climatic constraints : the Last Glacial Maximum (LGM)
Glace
Désert chaud
North–South migrations of European biotas (Huntley 1988) Inter-Glacial Full-Glacial
True migrations between ‘summer interglacials’ and ‘winter glacials’
PHYLOGEOGRAPH AND SUTURE ZONES
R R R
Genetic diversity is particularly high in the Mediterranean region
R R R R
G
I G
Taberlet et al., 1998
Distribution of richness (up) and rarity (below) of plants, birds and amphibians/reptiles in Europe (Araujo et al., 2005)
Plants Birds Herptiles
ENDEMISM RATES
Groups N Species % Endemism
Vascular plants 25 000 50.0 Freshwater fish 450 44.0 Reptiles 165 68.5 Amphibians 63 58.7 Mammals 197 25.5 Birds 343 17.0 Insects 150 000 + ? Very high
Drivers of biodiversity: downscaling from global to local
Global, northern hemisphere: macrogeographical processes
Regional (Mediterranean): Plio-Pleistocene history
Local : environmental gradients
Landscape: local disturbance regime (moving mosaic)
Habitat: structure and dynamics
Oro-mediterranean
Supra-mediterranean
Meso-mediterranean
Montane-mediterranean
Drivers of biodiversity: downscaling from global to local
Global, northern hemisphere: macrogeographical processes
Regional (Mediterranean): Plio-Pleistocene history
Local: environmental gradients
Landscape: local disturbance regime (moving mosaic)
Habitat: structure and dynamics
Primeval forest in ex-Yougoslavia (Mueller-Dombois, 1987)
metaclimax
Primeval forests are moving mosaics driven by disturbance events that initiate
successions
Succession of communities
Seral stages (succession = forest domain)
α α α α
γ β β β
Spatial scaling
The extent of ecosystem structural change is reflected by the horizontal distance from the original stable state. The effort required to return the degraded state to a trajectory of recovery towards the original stable state is reflected by the depth of the attraction basin
The forest domain: attraction basins
Extent of structural change from the stable steady state
Res
ista
nce
to sh
ift to
an
alte
rnat
ive
stab
le st
ate
High matorral Middle matorral
Low matorral
Dynamic mosaic of forest states
No fire
Fire
The extent of ecosystem structural change is reflected by the horizontal distance from the original stable state. The effort required to return the degraded state to a trajectory of recovery towards the original stable state is reflected by the depth of the attraction basin
Res
ista
nce
to sh
ift to
an
alnt
erna
tive
stab
le st
ate
Extent of structural change from the stable steady state After Ghazoul et al. 2015
Dynamic mosaic of forest states
Fire
Low fire return
The forest domain: attraction basins
High fire return No fire
‘Metasystem’ =
moving mosaïcs
Quercus Pistacia palaestina
Calicotome Pistacia lentiscus
Cistus Sarcopoterium
Paeonia mascula
Drivers of biodiversity: downscaling from global to local
Global, northern hemisphere: macrogeographical processes
Regional (Mediterranean): Plio-Pleistocene history
Local : environmental gradients
Landscape: local disturbance regime (moving mosaic)
Habitat: structure and dynamics
The size and
connectivity of habitat
patches depend on the
dispersal range and the
speed of dispersal of
organisms
27 Jedrzejewski et al.
1988
Dead wood habitats
By their massive production of lignous tissues that are difficult to recycle, forest ecosystems evolved the most complex set of communities of nutrient regenerating
organisms to be found in terrestrial ecosystems (succession of communities, diversity of adaptive types,
symbioses, competition, parasitism etc.)
Dead trees are spots of very high biodiversity
Drivers of biodiversity: downscaling from global to local
Global, northern hemisphere: macrogeographical processes
Regional (Mediterranean): Plio-Pleistocene history
Local : environmental gradients
Landscape: local disturbance regime (moving mosaic)
Habitat: structure and dynamics
Humans as ‘neo-drivers’ of
biodiversity
1987 2001
The lost Eden paradigm
The paradigm of the human-designed garden
2010
1ère
Produits forestiers
Fabrication du verre
Bois de feuCharbon de boisTanninBois de BuisHuile de cadeBois d’outillageFourragePharmacopée
Glands et fruitsChampignons
Pâturage
Viticulture
Pl. aromatiques
Révolution Guerres mondiales2nde
1750 1850 195019001800 2000
1ère
Produits forestiers
Fabrication du verre
Bois de feuCharbon de boisTanninBois de BuisHuile de cadeBois d’outillageFourragePharmacopée
Glands et fruitsChampignons
Pâturage
Viticulture
Pl. aromatiques
Révolution Guerres mondiales2nde
1750 1850 195019001800 2000
Produits forestiers
Fabrication du verre
Bois de feuCharbon de boisTanninBois de BuisHuile de cadeBois d’outillageFourragePharmacopée
Glands et fruitsChampignons
Pâturage
Viticulture
Pl. aromatiques
Produits forestiers
Fabrication du verre
Bois de feuCharbon de boisTanninBois de BuisHuile de cadeBois d’outillageFourragePharmacopée
Glands et fruitsChampignons
Pâturage
ViticultureViticulture
Pl. aromatiques
Révolution Guerres mondiales2nde
1750 1850 195019001800 2000
Révolution Guerres mondiales2nde
Révolution Guerres mondialesRévolution Guerres mondiales2nde
1750 1850 195019001800 200017501750 18501850 19501950190019001800 20002000
Ecosystem services from forests
The millenial transformations of Mediterranean forests
Selon l’usage que les humains en font, Les surfaces boisées peuvent être:
– Forêts de subsistance, – Forêt à usage industriel, – Forêts de production de bois, – Forêts sanctuaires – Forêts de pâturage – Forêts de récolte des fruits et
de produits divers (châtaignes, liège)
« Le forêt est un miroir de la
société » (A. Corvol 1987)
Début de la déforestation massive
9000 BP
5000 BP
Fairly high
low
moderate
moderate
high
high
high
low
high
Dehesa-montado
Silva-saltus-ager
Primitive oak forest
Effects of traditional land use practices on biodiversity
F. Bousquet & D. Gautier, 1999
Diversity
Take home messages • Biodiversity is a legacy of long-term processes that are rooted in a deep past operating from
local to global
• Forests functions and services depend on many habitat types which contribute to the dynamics of the system (old stands are not « better » than young ones)
• Local regimes of natural disturbance are a prerequisite for forest dynamics and for the survival of the historical legacy of biodiversity
• Connectivity among habitat patches of similar structure is necessary for long term survival of (meta)populations and (meta)communities
• Address key challenges of mitigation and adaptation to global change
• A golden rule, the ‘5 M’: « Making Mimics Means Managing Mixtures » (Dawson & Fry, 1998) (i.e. the sustainability of mimic systems depend on how well we work within the natural ecological forest dynamics)