NATURAL AREAS AND REGIONS 



605 



Geographic andfaunal communities 



With the exception of the highest 

 mountains the whole of Nicaragua is in 

 the Tropical Zone, and humidity is 

 consequently the chief factor in causing 

 varying plant and animal communities. 



Luxuriant tropical rain forest. The 

 entire Caribbean Slope is one of the 

 most humid areas in the New World. 

 It rains from mid-April to December, 

 and an annual fall of 250 in. is not 

 unusual. Hence the primeval unbroken 

 rain forest, the trees of tremendous 

 height, with the sun never reaching the 

 ground. The flora is unknown, but 

 many valuable timber trees such as 

 mahogany are abundant. The fauna 

 is extraordinarily abundant and varied. 

 Tapirs, jaguars, howling monkeys, 

 sloths, ant-eaters, and many bats and 

 rodents are characteristic. Over 400 

 species of birds, of neotropical groups, 

 are already recorded. 



Arid deciduous forest. The central 

 highlands are apparently a barrier to the 

 moisture-laden trade winds. As a re- 

 sult the Pacific Slope is much drier, 

 the rains are less heavy, and last from 

 mid-May to November. In the dry 

 season the rainfall is rapidly absorbed 

 or evaporated, and semi-arid conditions 

 prevail. Cactus is frequent, and the 

 dominant type of vegetation is a low 

 scrub. Originally a type of open gal- 

 lery forest is reported, but is now largely 

 destroyed, patches of this forest remain- 

 ing in a very few places, such as the 

 slopes of the volcanoes El Viejo and 

 Mombacho. We have here a dry Tropi- 

 cal Pacific Slope fauna and flora, quite 

 different from the Caribbean rain forest, 

 and much less^abundant and varied. 

 Two associations only can be distin- 

 guished, the open scrubby plains and 

 the gallery forest, with markedly differ- 

 ent floras and faunas, that of the latter 

 much more varied. Native report has 

 it that this gallery forest was originally 

 the predominating association, but 

 scientific evidence is lacking. There 

 are no rivers, lakes, or marshes. 



Very varied ecological and faunal 

 conditions prevail in the central and 

 northern highlands. Most of this region 

 has never been visited by a naturalist, 

 and consequently only a very general 

 account can be given. 



Semi-desert. Proceeding due north 

 from Lake Managua to the town of 

 Matagalpa at an altitude of 2200 ft., 

 the climate during the long dry season 

 is extremely arid, and the vegetation is 

 distinctly xerophytic, with a total 

 absence of herbaceous plants. The 

 birds are quite different from those of 

 the Pacific Slope. The extent westward 

 of this region is entirely unknown, but 

 its eastern limits are the eastern slopes 

 of the highlands, where the humid 

 Caribbean forest abruptly begins. 

 North of Matagalpa the mountains rise 

 from 4000 to 5500 ft. There are at 

 least two high valleys or plateaus known 

 at about 3500 ft. Here in addition to the 

 usual dry scrub association is found an 

 oak association, and these districts 

 support many species of birds known 

 nowhere else in the country. 



Conditions change abruptly above 

 3500 ft. Between this level and 5000 ft. 

 the mountains are covered with a pine 

 forest, with a totally distinct fauna and 

 flora. Many north temperate genera 

 of plants and birds, such as the Sweet 

 Gum, Crossbills, Siskins, Bluebirds, 

 and Flickers, here reach the southern 

 limits of their range. The birds are a 

 beautiful illustration of how favorable 

 ecological conditions have enabled them 

 to adapt themselves to a tropical cli- 

 mate. The altitude is apparently re- 

 sponsible for the great humidity, as it 

 rains in this pine forest belt throughout 

 the year, 



Montane forest. Very few of the 

 mountains are known to rise above 5000 

 ft., but this altitude is sufficient to 

 produce a genuine Subtropical Zone, 

 as defined by Chapman. These sum- 

 mits are covered by an excessively 

 dense, dark cloud forest, characterized 

 by tree-ferns, gigantic begonias, and an 

 astonishing wealth of epiphytes, para- 



