ABSTRACT BOOK Sandstone Landscapes ... - Sandstones.org

Krzysztof ŚwierkoszMuseum of Natural History, ul. Sienkiewicza 21, 50-335 Wrocław, Poland (krissw@biol.uni.wroc.pl)PThe Ishalo – the gem of MadagascarThe Ishalo Massif lies in the south-western part of Madagascar. It covers about 1000 square kilometres, andmost of its area is protected as a National Park. Ishalo is one of the earliest National Parks on the island,which protects the unique landscape of a sandstone massif dissected by a labyrinth of deep canyons and ajumble of ruiniform contours of strange appearance. The Ishalo Massif represents a part of the earliestsedimentary layers of the Permo-Trias karroo series, which was formed on the bottom of the old, PermianSea once covering part of the Gondwana continent (Battistini 1972). The climate is hot and rather dry. Theannual mean temperature equals about 25 o C, and the precipitation is about 1500 mm per month, but fallingalmost entirely in the hot season. The dry season may extend to several months (Donque 1972). In thephytogeographical divisions of Madagascar the area is comprised within the Centre Area (Koechlin 1972),which includes the central plateau region, above the average height of 800 m a.s.l.For a long period of time (about 1000 years) the Ishalo area has been under extensive anthropopressure dueto grazing, clearing and burning of forest, although stable settlements do not occur here.At present the area is covered by various type of vegetation. They include the relic (or secondary)formations of sclerophyllous forest with domination of Tapia sp. (Capparidaceae), Asteropeia sp.(Theaceae), Uapaca bojeri (Euphorbiaceae), Cussonia bojeri (Araliaceae) and other species. Another typeare the lax, forest formations with many gaps, where the many shrubs and herbaceous plants occurs. Themost common of these are Maesa lanceolata (Myrsinaceae), Aphloia theaeformis (Flaccourtiaceae) andmany endemic species of Helichrysum (Asteraceae), Catharanthus and Pachypodium (Apocynaceae) orXerophyta sp. (belonging to the endemic family Veloziaceae). Rock crevices harbour not only grasses andherbs, but also small endemic trees of Ficus and many succulent species of Aloe, Kalanchoë, Cynanchumand Euphorbia. There is also a wide area of pseudo-steppes with Aristidia rufescens, Trachypogon sp.,Heteropogon sp.and Imperata sp. here, which represents a relic of the old, grazing and burning, type ofIshalo management.ReferencesBATTISTINI R. 1972. Madagascar relief and main types of lanscape. [in:] R. BATTISTINI & G.RICHARD-VINDARD, Biogeography and Ecology in Madagascar. Dr. W. Junk B. V. Publishers, TheHague, pp. `1-25.DONQUE G. 1972. The climatology of Madagascar. [in:] R. BATTISTINI & G. RICHARD-VINDARD,Biogeography and Ecology in Madagascar. Dr. W. Junk B. V. Publishers, The Hague, pp. 87-144.KOECHLIN J. 1972. Flora and vegetation of Madagascar. [in:] R. BATTISTINI & G. RICHARD-VINDARD, Biogeography and Ecology in Madagascar. Dr. W. Junk B. V. Publishers, The Hague, pp. 145-190.PETITJEAN A. 2001. Madagascar par sa flore. 2 eme Edition. OCPFM, Antannarivo, 48 pp.SAMYN J. M. 2001. Plantes utiles des hautes terres de Madagascar. Alain Petitjean Editeur, SainteClotilde, 81 pp.ŚWIERKOSZ K. (in press). Vegetation of the central part of Madagascar - synanthropisation andprotection. – Wszechświat (in Polish).