Revue internationale d'écologie méditerranéenne International ...
Revue internationale d'écologie méditerranéenne International ...
Revue internationale d'écologie méditerranéenne International ...
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size class with box plot charts. MDNN values<br />
(according to four classes: 1 < 5001 m;<br />
2 = 5001 – 10000 m; 3 = 10001 – 15000 m;<br />
4>15000 m) were also projected on the distribution<br />
map of the populations. Significant<br />
differences between population size classes<br />
for altitudes and MDNN were tested by a<br />
bonferroni procedure (Hervé 2007) at the<br />
alpha 5% risk after correction.<br />
Results<br />
We updated the cartography of G. lobelii providing<br />
a nearly exhaustive distribution of the<br />
populations (Figure 1, Appendix 1). After<br />
three years of field investigations, we did not<br />
find two populations previously cited at “Forcalquier”<br />
and “Mont Coudon” sites (Rebuffel<br />
1998). We report five new populations, never<br />
cited previously on: Carpiagne mountain<br />
(CRP3), Garlaban mountain (GRL8), la<br />
Loube mountain (LB3), and Reigagnas mountain<br />
(TRT1). In addition, we found on Grand<br />
Bessillon site (BSS) a population which has<br />
not been observed by botanists since 1992<br />
(Rebuffel 1998).<br />
Genista lobelii occurs on a relatively large<br />
geographical range though with a highly frag-<br />
ecologia mediterranea – Vol. 36 (1) – 2010<br />
Distribution, habitat and population size variation of Genista lobelii (Fabaceae)<br />
from the calcareous mountains of Basse Provence (S-E France)<br />
mented pattern. The stations are mainly<br />
localised on the summits of the principal calcareous<br />
mountains of Basse Provence. Even<br />
at the scale of each mountain, the populations<br />
are often highly scattered. The most extreme<br />
pattern of isolation is observed for peripheral<br />
sites of Bessillon and cap Canaille with small<br />
patches of individuals, i.e. 10 individuals on<br />
10 m 2 and 15 individual on 20 m 2 respectively.<br />
The median distance to the nearest<br />
20 neighbors (MDNN) are 26.3, 21.1 and<br />
16.6 km for Bessillon (BSS), Mont Faron<br />
(FRN) and cap Canaille (CNL) stations<br />
respectively (Appendix 1). On the other hand,<br />
near the center of the distribution, along the<br />
Sainte-Baume (BM) and Sainte-Victoire<br />
(VCT) summits, G. lobelii occupies a large<br />
area of close stations (Figure 1). The average<br />
MDNN is 2.6 and 4.1 km for Sainte-Victoire<br />
(VCT) and Sainte-Baume (BM) stations<br />
respectively (appendix 1). The average<br />
MDNN is 12.4 km for all 108 G. lobelii stations.<br />
These patterns are also summarized on<br />
boxplots (Figures 2 and 3), showing that the<br />
highest population size class (>1000 m 2 ) is<br />
significantly associated to small isolation<br />
(small values of MDNN) and to high altitudes.<br />
However, there was no significant difference<br />
between population size classes 1<br />
and 2.<br />
Figure 2 – On left: box plot of median distance (m) of 20 most nearest neighbors of Genista lobelii stations according to surface area<br />
occupied (three classes: 1 = surface area < 100 m 2 ; 2 = surface area 100 m 2 – 1000 m 2 ; 3 = surface area > 1000 m 2 ). Different<br />
letters show significant median distance of 20 most nearest neighbors differences between population size categories at<br />
the alpha 5% risk after Bonferroni correction. On the right: spatial distribution map of G. lobelii, the symbol sizes<br />
proportional to the median distance of 20 most nearest neighbors (four classes: 1 < 5001 m; 2 = 5001-10000 m;<br />
3 = 10001-15000 m; 4 > 15000 m).<br />
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