<strong>EEP</strong> STUDBOOK CROWNED PIGEONS of grass, sedges and shrubs. With increasing altitude the forest patches and the trees themselves become smaller and smaller and finally peter out around 3900 m. Lowland and hill forests are further subdivided into northern and southern regions because the central mountain chain which runs from one end of the island to the other forms a barrier as there are no low altitude passes from north to south. These zones each have some characteristic animals while other animals are widespread through several zones (Menzies, 1991). Climate The climate is tropical and monsoonal with only two seasons, the wet and the dry. Temperatures vary significantly between the coast (20-35 °C) and the highlands (10-30 °C). Rainfall varies from 40 inches (40 x 2.54 cm) per annum in port Moresby to over 200 inches (5 meters) per annum in some localities (UBD, 1997). Flora With the generally humid and benign climate, it is not surprising that the native vegetation in most of the region is rainforest. From extrapolation data available from eastern New Guinea, it has been calculated that undisturbed native forest cloacks nearly 70 percent of the available land area (Campbell-Jones, 1995), which is a humid forest, for 58 percent. Savanna makes up for only 7 percent of New Guinea’s vegetation (Beehler, et al., 1986). Botanists have termed the flora “Malesian”, because of its part Asian, part Melanesian, origin. The lowland rainforest is structurally and taxinomicaly complex, usually with a high richness of species. A typical hectare sample would show dozens of families of trees. Canopy height reaches 40 m or higher, and vertical structure is complex, with a subcanopy of saplings, pandanus, palms, lianas, creepers and so on. Of course, as one ascends to higher altitudes, one finds gradual changes in forest structure and species composition. In mountainous country, the variables of slope, drainage, and natural succession brought about by land-slips produce mosaics of vegetatin types. Apart from these humid forest vegation there are other specialized habitats of restricted distribution, like the mangrove forests along the coastal areas, seasonal monsoon forests, at the edges of drier zones, savanna and open woodland wherever there is a long and severe dry season (Beehler, et al., 1986). Man-related alteration of the environment, although relatively limited in New Guinea, has nevertheless produced significant changes. Most prominent are the grasslands, which have developed in long-settled areas of the highlands and, less frequently, in lowland areas. In many areas, with increasing development, the tracts of grassland surrounding settlements continue to expand, with the local forest retreating. Demands for housing material, commercial timber, and firewood all act to create large areas of open habitat near permanent settlements. In both the highlands and the lowland grasslands, the bird communities are impoverished (Beehler, et al., 1986). 124
<strong>EEP</strong> STUDBOOK CROWNED PIGEONS Fauna As already mentioned, definitely the most remarkable species inhabiting New Guinea are the large <strong>number</strong> of monotremes and marsupials: four ordes, comprising 8 families with a total of 67 species, most of them also divided into many subspecies (Menzies, 1997). New Guinea and islands near by have a lot of <strong>pigeon</strong>s that are mainly terrestrial, like Goura, Trugon, Otidiphaps and Microgoura. It may be significant that these occur in an area where the only gamebirds of comparable size are the megapodes. The abundance of forest-dwelling arboreal <strong>pigeon</strong>s in the Austro-Malayan sub-region is probably, as was long ago suggested by Wallace (1865, in Goodwin, 1983), correlated with the absence of monkeys from this area, for these mammals are being considered serious predators on the eggs and young of any birds that build relatively unconcealed open nests in the branches (Goodwin, 1983). 125