TERRESTRIAL ISOpOD DIVERSITy IN THE WADI TAHADDART CATCHMENT AREA (N-W MOROCCO)

– We assessed the diversity of terrestrial isopods according to habitat in the wadi Tahaddart catchment area. The most representative habitat types in the area were selected within an altitudinal range from 0 to 119 m. In total twelve different habitats were sampled on May 2008: four with forest vegetations: a native dense oak forest, a degraded oak forest and two reforestations, three with maquis vegetation (natural and degraded), four at meadows and the coastal habitat of the Tahaddart River mouth dominated by halophilous vegetation. During the study, 2466 oniscideans belonging to 18 species and six families were collected. Terrestrial isopod structure differed among the 12 sampling habitats. The identified species belonged to five biogeographical categories, with 75 % of the species having a Mediterranean-Atlantic distribution and 25 %, a South-West European and North-West African distribution. The reforestation of Eucalyptus camaldulensis exhibited the highest values of diversity (H’ = 1. 89; J’ = 0. 91). Among the forests, the native oak forest of Quercus suber exhibited the lowest values of diversity indices. Except of the coastal habitat of the Tahaddart river mouth, which provided a habitat for a special terrestrial isopod assemblage, the studied sites were separated into open and closed areas based on the Euclidean distance. The distribution structure of the collected species was also analyzed according to altitude and plant assemblage. BIODIVERSITy ONISCIDEA NORTH AFRICA MAQUIS FOREST DEGRADED HABITAT FAUNAL SIMILARITy. 160 S. HAMAIED, M. S. ACHOURI, F. CHARFI-CHEIKHROUHA Vie milieu, 2013, 63 (3/4) Sampling methods: Samplings were carried out from the 6 to the 9 May 2008. As only one sampling was realized in this region, the protocol of Souty-Grosset et al. (2008), simple and reproducible, was applied. In each habitat, terrestrial isopods were hand Fig. 1. – Tahaddart catchment area (North West of Morocco) and sampling localities. Table I. – GpS coordinates, altitudes and plant assemblages of the 12 sampled habitats in the Tahaddart catchment area. Habitats Latitude ; longitude Altitude Plant assemblages 1 35°35’ 03.08” N; 5° 55’ 33.33’’ W 65 m a.s.l Maquis of Pistacia lentiscus L. , Cistus crispus L. and Juncus sp. , with very scattered feet of Quercus suber L. ; localized in the secondary road to tanger. 2 35°35’ 56.8’’ N; 5° 45’ 15.3’’ W 84 m.a.s.l. Open maquis of P. lentiscus, Cistus monspeliensis L. , Cistus sp. , Erica sp. with some feet of Chamaerops humilis L. and young Eucalyptus camaldulensis 3 35° 30’ 3.05’’N; 5° 46’ 9.03’’W 91 m.a.s.l. Dense forest of Q. suber with P. lentiscus, Cistus monspeliensis, Cistus sp. , Erica sp. with some feet of dwarf palm. 4 35°37’ 53.03’’ N; 5’ 50’ 17.7’’ W 26 m.a.s.l. Dry meadow with Carduus martinezii Pau subs. martinezii and feet of Chamaerops humilis. 5 35° 35’ 49’’ N; 5° 54’ 57.9’’W 95 m.a.s.l. Degraded wet meadow with some feet of Chamaerops humilis and annual plants. 6 35° 34’ 59.1’’N; 5° 55’ 25.9’’ W 72 m.a.s.l. Reforestation of Eucalyptus camaldulensis Dehnn with very scattered feet of Q. suber, Erica multiflora L. and Cistus crispus L. 7 35° 36’ 26.9’’ N; 5° 54’ 25.3’’W 75 m.a.s.l. Reforestation of Pinus pinaster subs. atlantica Villar with some feet of C. humilis. 8 35°38’ 1’’ N; 5° 51’ 18.9’’ W 14 m.a.s.l. Wet meadow with feet of Chamaerops humilis located in a hill slope. 9 35° 30’ 56.9’’N; 5° 48’ 27.5’’ W 53 m.a.s.l. Wet degraded meadow with some feet of C. humilis located on the riverside of the 9 April dam. 10 35° 32’ 07.1’’ N; 5° 43’ 11.8’’ W 119 m.a.s.l. Very degraded forest of Q. suber with P. lentiscus and C. humilis located in Dar Chaoui. 11 35° 30’ 07.2’’ N; 5° 46’ 21.6’’ W 63 m.a.s.l. Dense maquis of P. lentiscus, C. monspeliensis, with some feet of C. humilis and wild olive tree. 12 35° 35’ 05.8’’ N; 5° 59’ 17.4’’ W 0 m.a.s.l. Coastal habitat of the Tahaddart River mouth with halophilous vegetation: Limoniastrum monopetalum Boiss. , Cotula coronopifolia L. , Sarcocornia perennis (Miller), Aeluropus littoralis (Gouan) Parl. , Ruppia maritima L. sp. Pl. ONISCIDEA DIVERSITy IN A CATCHMENT AREA OF MOROCCO 161 Vie milieu, 2013, 63 (3/4) sampled, only once during this sampling period, by the three authors during a period of one hour, in order to obtain the same probability of capture. This time-effort procedure offered a semiquantitative information. Individuals were collected from under stones and leaf litter and preserved in 70 % ethanol. In the laboratory, sampled individuals were counted and identified. Aiming to define the different biogeographical categories to which are attributed the identified isopod species of the studied region, the following bibliographic references were consulted (Vandel 1956, 1957, 1958; Caruso & Lombardo 1983; Caruso & Di Maio 1996; Taïti & Ferrara 1996; Schmalfuss 2003). data analysis: Different ecological indices estimating the diversity in the studied habitats were used: the Berger-parker dominance index d (May 1975), with d = Nmax ⁄ N (Nmax, number of individuals of the most abundant species and N, the total number of individuals), the Shannon-Wiener index H’ and the pielou’s (1978) evenness index (J’) were estimated to analyze the evenness of a community. The pAST (palaeontological statistics) software (Hammer et al. 2001) was used to calculate these indices. Fauna dissimilarities among the different studied habitats were estimated using the Euclidean distance. The pRIMER 5.0 (plymouth Routines in Multivariate Ecological Research) software package (Clarke & Warwick 1994) was used to construct a complete linkage cluster analysis. The Canonical Correspondence Analysis (CCA) was applied to relate the species abundance to the vegetal assemblages and altitudes. This analysis was performed using the package XLSTAT V.7. 5.2 (Addinsoft, http://www.xlstat.com).