Revue internationale d'écologie méditerranéenne International ...

isolated to harbour high percentage of
endemism despite their mountain affinities
(30% of orophytes or Mediterranean mountain
plants).
Genista lobelii is found along a wide altitudinal
range i.e., from dry coastline mountains
chains at 320 m to colder and relatively humid
situation at more 1110 m. As for A. provincialis,
another endemic of Basse Provence
(Véla et al. 2008; Baumel et al. 2009), the
vegetation associated to G. lobelii is not
homogeneous as reflected by the multivariate
analysis (Figure 4) and floristic composition
(Table 1 and Appendix 2). This heterogeneity
reflects the existence of different habitats
within the distribution of G. lobelii with possible
effects on population sizes. At 800 m
(a.s.l.), on the summital crest of Sainte-
Baume, Sainte-Victoire and Trets (cluster
no 1), G. lobelii shows its ecological optimum
characterized with numerous and large populations.
At the opposite, on coastline mountain
chains (cluster no 3) and at 300-500 m (a.s.l.),
G. lobelii has smaller populations, less than 10
individuals occurring on 10 m2 , similar to
observation made on Cap Canaille stations.
ecologia mediterranea – Vol. 36 (1) – 2010
Distribution, habitat and population size variation of Genista lobelii (Fabaceae)
from the calcareous mountains of Basse Provence (S-E France)
Indeed, in this cluster (n o 3), Mediterranean
mountains plant species are less frequent than
thermophilous Mediterranean species such as
Pistacia lentiscus. Populations of G. lobelii
located at 500 to 800 m are mostly grouped
together (cluster n o 2). In majority, they are
isolated, reduced, under or beside an open formation
dominated by Quercus coccifera
and/or Quercus ilex. The expansion of this
vegetation type is promoted by land-use
changes i.e. pasture abandonment and recurring
fire (Tatoni et al. 2004). From these facts,
it could be hypothesized that G. lobelii probably
occupied larger areas at lowland position
or along mountain slopes during the last centuries
and is now threatened by forest succession.
For example, on Bessillon site (BSS), G.
lobelii forms a small population, only 10 individuals,
and is distant from the nearest population
by 17.95 km. Another good example
concerns the small population of the BMH1
station (cluster n o 2) near the “Hotellerie de la
Sainte-Baume”, found on grassland vegetation
type and threatened by colonisation of Quercus
pubescens Willd. It appears that distribution
of G. lobelii, like numerous open habitat
Appendix 2.2 – Cluster no 2
Species Frequence Family Biological Seeds Biological Demographic Biogeography
(%) cycle dispersal traits stratigies
Thymus vulgaris subsp. vulgaris 97 Lamiaceae Perennial Zele Ch S Steno-W-Medit.
Fumana ericoides subsp. montana 92 Cistaceae Perennial Apro Ch SR Steno-Medit.
Amelanchier ovalis (s.l.) 82 Rosaceae Perennial Zend P CS Medit.-Mont.
Helichrysum stoechas 79 Asteraceae Perennial Apro Ch S Steno-W-Medit.
Rosmarinus officinalis 79 Lamiaceae Perennial Zele NP CSR Steno-Medit.
Aphyllanthes monspeliensis 74 Aphyllanthaceae Perennial Apro H S Steno-W-Medit.
Sesleria caerulea (s.l.) 64 Poaceae Perennial Apro H CS Oroph. C-Europ.
Anthyllis vulneraria (s.l.) 62 Fabaceae Annual, Perennial Alou Th, H SR Eurasiatic
Koeleria vallesiana subsp. vallesiana 62 Poaceae Perennial Apro H S Euri-Medit.
Brachypodium retusum 59 Poaceae Perennial Zepi Ch CS Steno-W-Medit.
Helianthemum oelandicum subsp. italicum 59 Cistaceae Perennial Apro Ch SR Euri-N-Medit.
Ononis minutissima 59 Fabaceae Perennial AuM Ch S Steno-W-Medit.
Echinops ritro 56 Asteraceae Perennial Alou H SR Steno-Medit.
Galium corrudifolium 56 Rubiaceae Perennial Zepi H S Steno-Medit.
Cerastium arvense subsp. suffruticosum 51 Caryophyllaceae Perennial Apro Ch S Oroph. S-Europ.
Teucrium polium subsp. polium 51 Lamiaceae Perennial Zele Ch S Steno-Medit.
Avenula bromoides (s.l.) 49 Poaceae Perennial Zepi H S Steno-W-Medit.
Helianthemum oelandicum subsp. incanum 49 Cistaceae Perennial Apro Ch SR Oroph. S-Europ.
Teucrium chamaedrys (s.l.) 49 Lamiaceae Perennial Baro Ch CS Euri-Medit.
Festuca marginata subsp. marginata 46 Poaceae Perennial Zepi H S Endem. W-Alpica
Genista hispanica subsp. hispanica 44 Fabaceae Perennial AuM Ch S W-Medit.-Mont.
Juniperus phoenicea subsp. phoenicea 44 Pinaceae Perennial Zend P CS Euri-Medit.
Quercus ilex (s.l.) 44 Fagaceae Perennial Zdys p CS Steno-Medit.
Seseli galloprovinciale 44 Apiaceae Perennial Baro H S Subendem.
Quercus coccifera 41 Fagaceae Perennial Zdys P CS Steno-W-Medit.
Juniperus oxycedrus subsp. oxycedrus 38 Pinaceae Perennial Zend p CS Euri-Medit.
Arenaria aggregata 36 Caryophyllaceae Perennial Apro Ch S NW-Medit.-Mont.
Odontites luteus subsp. luteus 36 Scrophulariaceae Annual Apro Th SR Euri-Medit.
Crepis albida 33 Asteraceae Perennial Aleg H S Oroph. SW-Europ.
Iberis stricta subsp. leptophylla 33 Brassicaceae Biennial Baro Th, Ch SR Subendem.
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