Diversité des Arthropodes de sous-bois des forêts sèches de Madagascar

Diversity of understory arthropods in the dry forests of Madagascar. The arthropods of Madagascar are among the most poorly known animal groups on the island. The principal objective of this study was to determine the diversity of this group at three different localities in lowland dry forests of western Madagascar. The three sites, all inventoried during the dry season in 2017, include: the Ankarafantsika National Park (16°18’S, annual rainfall: 867 mm) in the northwest; the forest of the Centre National de Formation, d’Études et de Recherches en Environnement et Forestier (CNFEREF) at Kirindy (20°04’S, annual rainfall: 555 mm) in the central west; and the Tsimanampesotse National Park (24°01’S, annual rainfall: 334 mm) in the extreme southwest. Malaise and pit-fall traps were used to capture arthropods and 24 orders belonging to 133 families were identified. The community at Ankarafantsika was the most diverse with 19 orders and 89 families with a more balanced taxonomic representation, while Tsimanampesotse had 18 orders and 69 families and Kirindy CNFEREF had 17 orders and 70 families. Calculated similarity between the different sites at the family level was relatively high, while that at the order level relatively low even given a certain level of homogeneity was noted between the three localities. The composition of arthropods in the dry forests of Madagascar varies according to local conditions, which include bioclimatic factors, and the characteristics of the vegetation at the three localities.