Vol. 32 – 2006 - Ecologia Mediterranea

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MOHAMED TARHOUNI, AZAIEZ OULED BELGACEM, BELGACEM HENCHI, MOHAMED NEFFATI 44 Figure 4 – Percent cover of plants depending on the season drought and the distance from watering points combined at well 2. See Table 1 for ANOVA results. Values are means ± IC. a/b/c indicate differences for Hemicryptophyte plants and 1/2 for CRS plants. Figure 5 – Percent cover of plants depending on the season drought and the distance from watering points combined at well 3. See Table 1 for ANOVA results. Values are means ± IC. a/b indicate differences for Therophyte plants. Plant cover (%) 35 30 25 20 15 10 5 0 Th Th Th Th Th Th Th Th 250 m 500 m 1 km 2 km 250 m 500 m 1 km 2 km Fall String spring far from well 2 while it was the lowest close to well 2 in both the rainy and the dry season (Table 1; Figure 4). RS covers are not significantly influenced by distance from watering points. S cover increases significantly with increasing distance from watering point at well 1, while it increases and then becomes relatively stable at well 2. a Discussion ab The main results of this study show that Therophyte, arido-passive, RS and CRS plants are particularly adapted to drought as they increase greatly in the rainy season (spending the dry season as seeds, etc.). Chamaephyte, arido-active, S and CS plants are particularly sensitive to disturbance and thus not adapted to high trampling and grazing. Hemicryptophyte and CRS plants are also sensitive to disturbance but to a lesser extent than previous species. b ecologia mediterranea – Vol. 32 – 2006 b
Chamaephyte species are better adapted to seasonal drought because they reduce their transpiration and assimilation organs particularly in summer (Raunkiaer 1934). Our results seem confirm this because we show that the Raunkiaer biologic spectrum is dominated by chamaephytes and hemicryptophytes during the dry period. Likely, therophytes seem to be more resistant to the fall drought than hemicryptophyte plants because they spend the dry period in dormancy (seeds), germinate since the first rain and dominate other plants whereas chamaephytes conserve their vegeta- ecologia mediterranea – Vol. 32 – 2006 A preliminary overview of the effects of seasonal drought and animal pressure around watering points on plant species using adaptative strategy analyses in the Tunisian arid zone Figure 6 – Percent cover of plants classified with Noy-Meir types depending on the season. See Table 1 for ANOVA results. Values are means ± IC. a/b indicate differences for AP plants and 1/2 indicate differences for AA plants. Plant cover (%) 70 60 50 40 30 20 10 0 AA AP Well 1 AA AP Fall Spring b 1 a AA AP Well 2 2 AA AP Fall Spring b a AA AP Well 3 AA AP Fall Spring Figure 7 – Percent cover of plants classified with Noy-Meir types depending on the distance from watering points. See Table 1 for ANOVA results. Values are means ± IC. a/b/c indicate differences for AA plants. Plant cover (%) 60 50 40 30 20 10 0 a ab b AA AP AA AP AA AP AA AP AA AP AA AP AA AP AA AP AA AP AA AP AA AP AA AP 250 m 500 m 1 km 2 km 250 m 500 m 1 km 2 km 250 m 500 m 1 km 2 km Well 1 c a b b b Well 2 Well 3 tive organs (Box 1987). For this reason therophytization phenomenon can be a characteristic of plant communities in the arid zone or in a contrasted climate with an arid season (Floret & Pontanier 1982). Therophytization also seems to be a major phenomenon that characterizes the degraded arid zone because annual plants are dominant in the more disturbed zone particularly around watering points (Tarhouni et al. 2007). Besides the therophytization, in the Tunisian arid zone, is aggravated by the domination of no/few palatable species in particular some hemicrypto- b 45
Page 1 and 2: ecologia mediterranea Vol. 32 - 200
Page 3 and 4: ecologia mediterranea Revue interna
Page 5: Pr Thierry DUTOIT Éditeur en chef
Page 8 and 9: AMAR MADOUI, JEAN-MARIE GEHU, DJAME
Page 17 and 18: Écologie trophique de la Cigogne b
Page 31 and 32: Priority Zones for Mediterranean pr
Page 33 and 34: zones of the steppe range play a pi
Page 35 and 36: 10%); and (iii) barren steppe (B-st
Page 37 and 38: occur from small subpopulations rat
Page 39 and 40: Franco A.M.A. & Sutherland W.J., 20
Page 41 and 42: A preliminary overview of the effec
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Page 49 and 50: from watering points. One third (1/
Page 51 and 52: Recherches sur les peuplements de m
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Page 55 and 56: Échantillonnage ecologia mediterra
Page 61 and 62: .1 Les subdivisions du rhithral et
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Page 66 and 67: PIERRE GRILLET, MARC CHEYLAN, FRAN
Page 76 and 77: RÉDDA ABOURA, DJAMEL BENMANSOUR, N
Page 88 and 89: BOUAMAR BAGHDAD, MUSTAPHA NAIMI, AB
Page 94 and 95: Résumés de thèses Catherine BRET
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Résumés de thèses construit une
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Résumés de thèses Vincent OLLIVI
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Résumés de thèses Lure, les for
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Vol. 32 – 2006 - Ecologia Mediterranea

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