Conservatoire et Jardin botaniques de la Ville de Genève
Flore et végétation des massifs forestiers du nord de Madagascar
The study of Madagascar Flora in Geneva draws back to De Candolle with the description of numerous species sampled by the earliest explorations (Commerson, Bojer). By the end of XIXth century, Auguste de Candolle desribed further species based on specimens collected by Mocquerys, then Hochreutiner worked on Guillot and Rusillon collections. In the 1970's Bernardi brought important collections assembled during his explorations in tthe Southern hemispherel. Genva curators participated to theongoing Flore de Madagascar (Hochreutiner : Malvaceae, Sterculiaceae ; Bernardi : Cunoniaceae) More recently several inventories and vegetation study projects have been conducted by CJB: 1. Central High Plateaux Forests 2. Flora and vegetation of Manongarivo Special Reserve 3. Flora and vegetation of Daraina 4. Flora and vegetation of Montagne d’Ambre 5. Flora and vegetation of Ampasindava peninsula 6. Flora and vegetation of Andrafiamena 7. Flora and vegetation of Beanka forest
Beanka forest is located North of Bemahara National Park, in the Western Domain. It is a limestone area of tropical eroded limestones locally called "Tsingy", with numerous crevices and sharp peaks. Climatic conditions are harsh, with limited precipitations during 6 months. In addition there is often very low water retention due to bare soils and porosity of bedrock, so that access to water is clearly the limiting factor for vegetation. A preliminary study conducted by zoologists confirmed the interest of the area, including a new species of bird. The forest has almost never been prospected except for 10 days in 2009. We anticipate numerous rare or new species. This study will also bring elements for conservation planning in the area.
The seasonally dry deciduous, transitional and humid forests of Andrafiamena, in the very North of Madagascar, were classed as `Paysage Harmonieux Protégé' last year. This means, according to the definition of the Ministry of Environment, Water, Forests and Tourism, that it is a `protected area where the interactions between man and nature contribute to the maintenance of biodiversity and cultural and esthetic values'. This conservation status, corresponding to the IUCN category V, has been achieved by the NGO Fanamby, to which the protection of this area is delegated. In order to truly achieve the goal of this newly created protected area, i.e. to promote sustainable development in local villages and at the same time prevent any further loss of biodiversity, Fanamby needs a solid scientific understanding of the plant and animal life present in the remaining forests of Andrafiamena. It is obvious that the rich plant and animal biodiversity of Andrafiamena has not yet been studied sufficiently. Firstly, according to the preliminary survey by the NGO Fanamby (Fanamby Webpage), there are only 211 species of plants in the forests of Andrafiamena and Andavakoera (on the total area of approximately 80 000 ha). This figure seems underestimated in comparison with similar forest types located fewer than 30 km from Andrafiamena, in the Loky-Manambato region. Secondly, according to the current map of remaining primary vegetation of Madagascar, the vegetation of Andrafiamena is simply a dry, deciduous forest, with only a small patch of degraded humid forest. According to the observations by Fanamby, the transitional and humid forests are not adequately represented (Figure 1). A detailed study of the vegetation of Andrafiamena is needed at this time in order to establish the potential presence of any threatened or endemic plant species, as well as to create an updated vegetation map of this potentially very valuable area. For the NGO Fanamby, it is crucial to have such information now, at the outset of projects within this protected area. On the one hand, knowing areas of high conservation priority, Fanamby will be able to encourage human activities in areas of lower conservation importance. On the other hand, a detailed vegetation map will be indispensable for pinpointing areas of interest for ecotourism.
Montagne d'Ambre is a volcanic massif of recent surrection, isolated in the North of Madagascar in a vegetation of dry forest. Evergreen humid forest is found on the upper part of the massif (from 800 m up to the top at 1475 m) which experiences a cooler and more humid climate. The isolated situation of this humid forest can explain the presence of local endemics, which is one of the reasons why a national Park has been created on the Montain. Due to their isolated situation in discontinuity with the mountains of the Central Domain and their relatively young origin, the forest of Montagne d'Ambre question the long distance dispersal abilities of its components. Their relationships with the dry forests of the foothills are also examined and bridge with other projects in the same program. This projects aims at supplementing existing floristical data through selective area sampling and vegetation inventories. Effectively, most prospecting efforts conducted until now were mainly centered on a restricted area near the research station., leaving the heart of the mountain and its Western slopes much underprospected. In a first phase, six camps have been prospected in the upper part of the massif and collecting and vegetation sampling has been conducted for 10-15 days in each camp. In a second phase, we will adress the vegetation of the foothills and the transition towards the dry forest of the surrounding plains.
The Sambirano phytogeographical Domain is a keystone for the understanding of the biogeography of Northern Madagascar, and basic data are critically lacking. The Ampasindava is one of the last places where these data are accessible before deforestation will wipe them definitely. The peninsula is located in Northwestern Madagara and covers 145'000 ha, representing on its own 30% of the Sambirano Domain area, which hosts evergreen rainforest homologous to the ones on the Eastern Coast of Madagascar). Ironically, this peninsula has remained virtually unknown, being of a difficult access: only 0.5% of all botanical collections in the Sambirano Domain come from there. Taking into consideration the size of the peninsula and the endemicity of the Domain, we can hypothetise that it is the real heart of the Domain. This project aims at collecting basic data for the knowledge of the flora and vegetation of the peninsula, and to interpret this data to get a better understanding of the Sambirano flora. In a first phase, six camps have been established covering the 4 principal regions where primary forest is still extant. In a second phase we will extend these prospections to mature secondary forests to address conservation issues.