- Madagascar dry deciduous forests
The Madagascar dry deciduous forests represent a tropical dry forest
ecoregiongenerally situated in the western part of Madagascar. The WWF has designated these forests as a Global 200ecoregion, one of the world’s most crucial regions for conservation. These western dry forests are characterized by upper stories of deciduous canopyextending to a height of 14 to 30 meters, and lower stories with dense shrubs and saplings, which may also contain some evergreen species. Rainfallis decidedly less than the eastern lowland rainforests of Madagascar, attaining levels as low as 50 centimeters per annum in the southwest to 200 centimeters per annum in the northwest. Trees have adapted to the drier climate by shedding leaves in the dry winter season (May to September) to limit winter evapotranspiration. Moreover, some species like baobabs have adapted by evolving the ability to store copious water in their large bulbous trunks.Nick Garbutt, Hilary Bradt and Derek Schuurman, "Madagascar Wildlife", Globe Pequot Press (2001)]
These dry deciduous forests of Madagascar possess a very high ratio of species
endemism, although the absolute number of total endemics is less than the wetter eastern rainforests of the island. The elevation of dry deciduous forests here spans the coastal plainwith its limestone plateaus emanating virtually at sea level to higher altitudes to 800 meters. Considerable anthropogenicdestruction has occurred, decimating whole regions of the forest, almost all of which has been driven by subsistence farming. After clearcutting and burning, a residual sparse, sometimes sterile grassland savannais relict. Because trees grow slowly in the rocky soils, regeneration time may be measured in centuries, but the toll of extinctspecies is permanent. Several distinct subregions are found within the western dry forest zone, several of which will be discussed separately here.
Summer daytime temperatures commonly exceed 30 degrees Celsius in all the Madagascar dry deciduous forests. One characteristic in common with other
tropical and subtropical dry broadleaf forestsis the presence of relatively high densities of mammalian biomass. Like these other dry forests, the Madagascar dry deciduous forests are sensitive to overgrazingand deforestation. An interesting feature of these dry forests is the presence of Pachypodium habitats, often associated with tsingy outcrops. There are numerous distinct forests within the biome, Madagascar dry deciduous forests; the following text treats three of these, selected for representativeness as to location and size.Nick Garbutt, Hilary Bradt and Derek Schuurman, "Madagascar Wildlife", Globe Pequot Press (2001)] Nick Garbutt, Hilton Hastings, Wendy Pollecutt, C. Michael Hogan, Tahiana Andriaharimalala, "Anjajavy, the village and the forest". May, 2006]
Ankarana Special Reserve
Ankarana Massifconsists of a limestone shelf which imposes a picturesque landform on the few adventurers who find this remote forest. As the limestone has weathered over geologic time, this karstformation often exhibits spiry pinnacles, called " tsingy" by the natives. The name derives from the Malagasyword which means "walk on tiptoe", used by the earliest settlers from around 1500 years ago to describe the sharpness of the rugged limestone shelves. There are an abundance of limestone caves and virgin forests that shelter the diverse wildlifeof the Ankarana region. In many cases the cave roofs collapse and form forested gorges through which rivers may flow.
The Ankarana Special Reserve is one of the northernmost reaches of the Madagascar dry deciduous forests, and correspondingly very hot December through March with this equatorial proximity. Access to wildlife viewing is through strenuous hiking, given the elevation differences, complex terrain and heat, but
four-wheel drivevehicles can reach most of the actual campsites. Below the massif is a grassy plain that leads to the Indian Ocean. In the higher elevations Lac Vertis perched among tsingy formations.
Mammals found in this forest include the
apex predatorFossa ("Cryptoprocta ferox"), the Fanaloka("Fossa fossana"), Northern Ring-tailed Mongooseand numerous batspecies. [Nick Garbutt, "Mammals of Madagascar", Pica Press (1999)] Lemurs occurring here are the Crowned Lemur, Northern Sportive Lemur, Gray Mouse Lemurand Sanford's Brown Lemur. [Russell Mittermeier et al., "Lemurs of Madagascar", Conservation International (1994)] Numerous geckos inhabit the Reserve including Leaf-tailed Gecko, Big-headed Gecko and Day Gecko.Nick Garbutt, Hilary Bradt and Derek Schuurman, "Madagascar Wildlife", Globe Pequot Press (2001)] Other local reptiles are the Madagascar Ground Boa, the White-lipped chameleon("Forcifer minor") and Oustalet's chameleon, the world's largest chameleon, which can attain 68 centimeters in length.
Some bird species commonly seen are the
Hook-billed Vanga, Madagascar Pygmy Kingfisher, Crested Coua, White-breasted Mesiteand Madagascar Ibis. Raptors sighted in the reserve include the Madagascar Harrier Hawkand the Madagascar Scops Owl. Other avafauna occurring here include Red-capped Couaand Coquerel's Coua, and the vangas Van Dam's Vanga, Rufous Vangaand Sickle-billed Vanga. Vangas are significant in Madagascar, as 15 of the 16 vanga species are endemic to Madagascar. The Greater Vasa Parrotand Madagascar Green Pigeonare also indigenous. An important endangered species, the Madagascar Fish Eaglehas a number of breeding pairs located in the Ankarana Reserve. [Gemma Pitcher and Patricia C. Wright, "Madagascar and Comoros", ISBN 1-74104-100-7]
Anjajavy Forestis an example of a purely lowland dry deciduous forest in northwest Madagascar. It is punctuated with numerous tsingy outcroppings and limestone karstcaves, and in many locations abuts the Indian Ocean, especially where the dramatic tsingy formations jut out into the ocean. The canopy height is typically 15 to 25 meters high, and is at its lowest at the coastal verge, where growth may be impeded by saline rocky soils. The forest resides on a small peninsulaof land poking into the Indian Ocean, that is bounded on the north and part of its eastern extent by the Bay of Narinda and on the south by the Bay of Majajamba. Access to this forest is difficult since there are no roads connecting this peninsula to the Madagascar highway system; however, arrival by sea and by air are accomplished with some effort.Nick Garbutt, Hilton Hastings, Wendy Pollecutt, C. Michael Hogan, Tahiana Andriaharimalala, "Anjajavy, the village and the forest". May, 2006]
In many places at the ocean edge as well as forest interior, several tree species are capable of taking root directly in the tsingy rocks. Several species of
baobaband tamarindare among the tallest species forming the canopy. Considering the lower precipitation rates on the west coast (about 130 centimeters per annum at Anjajavy Forest), the vegetation is surprisingly verdant in the beginning of the dry season, but eventually will become mostly leafless by late winter. The forest understory is moderately dense but not impenetrable to the determined explorer. Nor is the understory heavily thorned in most locations.
The Anjajavy Forest is named for the Jajavy tree, which is endemic only to the forest itself. and, in fact, only is found within a five kilometer radius of Anjajavy village. Abundant diurnal lemurs that are found here include the
Coquerel's Sifakaand the Common Brown Lemur. One nocturnal species of mouse lemur is seen, but its precise species is yet to be documented. A variety of birds are present including the endangered species Madagascar Fish Eagle, which has four (of the approximately 99 known) breeding pairs resident in Anjajavy Forest. Other birdlife present are the Crested Coua, kingfishers, Madagascar Wagtailand Magpie Crow. Numerous lizards, chameleons and snakes populate the forest and are easily seen from the sparse trailnetwork.
The dry forest is invaded by fingers of
mangrove swampin the form of riparian zones at several small coastal estuaries at the western verge of the Anjajavy Forest, where small tidal streams flow into the Indian Ocean. The species of the mangrove swamps are, of course, totally different from the dry forest, and the transition zone supports an interesting ecotone, providing unusual niches for several species of animals.
Not a part of the official Madagascar National Park System, Kirindy Forest at coord|-20.070000| 44.6569|region:MG-U_type:landmark|name=Kirindy Forest is a private park situated in the southwestern part of Madagascar, 40km northeast of the town of
Morondava. The forest was earlier operated as an experimental sustainable timber harvestingscheme, which activity has not left indelible scars on the region. Most of the canopy top is about 14 meters in height, but in wetter parts (e.g. in riparian zones) it may almost triple in vertical extent. There are three species of baobab trees present: " Adansonia grandidieri", " Adansonia rubrostipa" and " Adansonia za". [George E. Schatz, "Generic Tree flora of Madagascar", Royal botanic Gardens, Kew, Crowmwell Press, United Kingdom (2001) ISBN 1-900347-82-2]
Kirindy Forest, approximately 100 square kilometres in area, may be best known as the only location where the
endangered speciesGiant jumping rat ("Hypogeomys antimena") occurs. This animal can hop like a miniature kangaroo, but is also seen walking on all four limbs. There are a number of species of nocturnal lemurs present: Red-tailed sportive lemur, Pygmy mouse lemur, Gray mouse lemur, Pale fork-marked lemur, Coquerel's Giant Mouse Lemurand the Fat-tailed dwarf lemur. Further mammalian species of fossa, Narrow-striped mongoose, Verreaux's Sifaka, Common tenrec, Greater hedgehog tenrec and Red-fronted Brown Lemurare also found here.
Some of the local reptiles present are: Labord's chameleon, various plated lizards, Leaf-tailed
gecko, Big-headed gecko, Madagascar Ground Boa, Giant hog-nosed snake, Spear-nosed snake and Kapidolo.
Madagascar's dry deciduous forests have been preserved generally better than the eastern
rainforests or the high central plateau, presumably due to historically less population density and scarcity of water; moreover, the present day lack of road access further limits human access. There has been some slash-and-burnactivity in the western dry forests, reducing certain forest habitat and applying pressure to some endangered species. Slash-and-burn is a method sometimes used by shifting cultivators to create short term yields from marginal soils. When practiced repeatedly, or without intervening fallow periods, the nutrientdeficient soils may be exhausted or eroded to an unproductive state. Further protection of western forests would assist in preservation of these diverse ecosystems, which have a very high ratio of endemic organisms to total species.Madagascar has many lemurs and 99.9% of the species is endangered due to habitat destruction.
Tropical and subtropical dry broadleaf forests
List of national parks of Madagascar
* [http://taniko.free.fr/parks/ankarana.htm Ankarana Reserve, Parcs et reserves de Madagascar, le site officiel]
* [http://maps.google.com/maps?f=q&hl=en&q=Anjajavy%2C%20Madagascar&t=h&om=1&ll= Anjajavy Forest Google satellite map]
* [http://www.unusualdestinations.com/485.htm Further detail on Kirindy and Ampijoroa Forests]
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