Revue internationale d'écologie méditerranéenne International ...

Number of quadrats
ecologia mediterranea, tome 29, fascicule 2, 2003, p. 139-152
VEGETATION ANALYSIS OF THE DOWN-STREAM PART OF WADI GAZA, PALESTINE ◆
T
10
O
7
B
13
Habitats
L
6
W
2
S
2
D
1
Total mean ± SD F-value
Percentage of fi rst dominant species in habitats
I. Arthrocnemum macrostachyum -- -- -- -- -- 100 --
II. Mesembryanthemum crystallinum -- -- -- 100 -- -- --
III. Tamarix nilotica, Arundo donax -- -- 20 60 -- -- 20
IV. Tamarix nilotica 38 25 12 -- 25 -- --
V. Alhagi graecorum Xanthium spinosum 15 8 77 -- -- -- --
VI. Centaurea ammocyanus, Atractylis carduus 46 36 9 9 -- -- --
Community variables
Total cover 38.7 47.1 35.1 40.4 57.8 59.3 12.2 40.6±18 0.72
Total number of species 30 28 30 29 17 8 6 21±10.6 --
Species richness (spp./stand) 7.8 6.4 9.2 11.2 10.5 5.5 6.0 8.5±2.5 2.08
Species turnover 10 7 12.9 6 2 2 1 5.8±4.4 --
Shannon index 0.59 0.41 0.55 0.64 0.78 0.33 0.28 0.55±0.1 1.43
Simpson index 0.47 0.54 0.47 0.33 0.25 0.60 0.70 0.46±0.1 1.03
Soil variables
Sand 79.6 74.6 68.4 93.3 94.0 96.0 90 79.2±12 1.79
Silt 15.0 18.0 23.6 5.3 6.0 4.0 6.0 15.5±8.9 1.89
Clay (%) 5.4 7.4 7.9 1.3 0.0 0.0 4 5.29±4 1.01
CaCO3 11.3 10.7 11.6 7.2 7.4 7.8 4.8 10.2±1.8 3.93**
EC (mS/cm) 1.9 7.5 6.1 12.5 5.2 2.0 1.8 5.9±4.2 2.01
pH 7.78 7.75 7.64 8.02 8.11 7.76 8.1 7.79±0.2 1.51
NO3 (mg/l) 474 859 627 368 126 229 43 534±439 0.51
Cl 8.6 41 38 100 39 26 14.4 39.4±31 2.4*
HCO3 5.6 6.1 5.8 6.6 5.6 11.0 4.0 6.1±2.9 0.65
Ca (meq/l) 23.7 80.3 62 201 31 27 13.4 71.8±25 1.29
Na 11.7 37 37.3 48.7 53.3 28 11.6 32.5±35 1.15
K 2.2 1.9 1.1 5.6 2.1 2.8 1.0 2.3±2.4 1.01
Table 3. Percentage of the characteristic species of 6 vegetation units in habitats,
mean of the community and soil variables of the main habitats in the down-stream part of wadi Gaza.
T: wadi terrace, O: wadi slope, B: wadi bed, L: bank of mouth pond, W: water edge of mouth pond, S: sand sheets, D: sand dune.
SD: standard deviation, * p ≤ 0.05, ** p ≤ 0.01, according to one-way ANOVA.
Tamarix nilotica (IV), Alhagi graecorum - Xanthium spinosum
(V) and Centaurea ammocyanus - Atractylis carduus
(VI). The second DCA axis revealed clear salinity, and
land form (topographic) gradients from the bank of the
mouth pond to the terrace of the main channel (fig. 3,
table 2).
The bank of the mouth pond had the highest values of
species richness (11.2 spp./stand), salinity (12.5 mS/cm),
Cl (100 meq/l) and cations Ca, Na and K (201, 48.7 and
5.6 meq/l, respectively). The sand sheets had the highest
values of total cover (59.3 %), Simpson index (0.60),
sand (96 %), bicarbonates (11.0 meq/l), and the lowest
of species richness (5.5 spp./stand), Shannon-Wiener
index (0.33), silt (4.0 %) and clay (0.1 %). The bed of
the main channel had the highest values of silt (23.6 %),
clay (7.9 %) and CaCO 3 (11.6 %); and the lowest of
plant cover (35.1 %), sand (68.4 %) and K (1.1 %). On
the other hand, the terrace of the main channel had the
highest values of total species (30) and the lowest of salinity
(1.9 mS/cm), Cl, HCO 3, Ca and Na (8.6, 5.6, 23.7,
and 11.7, respectively) (table 3).
The Arthrocnemum macrostachyum unit (I) had the
highest values of sand (98 %), salinity (21.7 mS/cm),
pH (8.14), Cl (168 meq/l), Ca (452 meq/l), Na (1338
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