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NATURALIST'S GUIDE TO THE AMERICAS 



several broad valleys. There are nu- 

 merous characteristic plants and ani- 

 mals. Even from the train the casual 

 traveller will notice the absence of 

 palm jungles, and the wayside fields 

 will have flowers, reminding him subtly 

 of a more northern latitude. 



Montane Forest. From 5000 to 8000 ft. 

 lies what might be called the upper 

 plateau region. It is again forested, 

 the forest exceedingly dense with an 

 abundance of epiphytic vegetation, and 

 tree ferns are noticeable and char- 

 acteristic. The varied fauna is in part 

 derived from the north, but is composed 

 chiefly of species of tropical origin, 

 which have become adapted to lower 

 temperatures. In the plant world, 

 numerous boreal genera appear (such 

 as Carex) or groups very closely related. 



Subalpine evergreen forest. The tem- 

 perate zone extends from about 8000 

 ft. to tree-line on the highest summits. 

 It is very humid, the forest is spreading, 

 stunted and gnarled, due to the high 

 winds, and contains oaks and other 

 arboreal species characteristic of a more 

 northern flora. Some of the most 

 remarkable of Costa Rican birds occur 

 in this zone, such as Zeledonia, the type 

 of a distinct family, the beautiful re- 

 splendent trogon, or quetzal (Pharomac- 

 rus mocinno), the unique peg-billed 

 sparrow (Acanthidops bairdi), and types 

 of clearly northern origin, such as a 

 hairy woodpecker, an ant-eating wood- 

 pecker, and a hummingbird (Selasphorus 

 flammula) closely related to species of 

 Mexico and western North America. 

 Above tree-line on the highest volcanoes, 

 living in the scrubby bushes occurs a 

 junco or snow-bird (Junco vulcani}. 



II. PRESENT BIOTIC CONDITIONS 



The greater part of Costa Rica is 

 still in a primeval and unspoiled con- 

 dition. There are three principal ex- 

 ceptions. The lower plateau region, 

 as already mentioned is thickly settled 

 and thoroughly cleared. As it was 

 originally forested, great changes from 

 original biotic conditions must have 



taken place. In the northwestern sec- 

 tion, just as in Nicaragua, the Indian 

 civilization removed most of the original 

 gallery forest, leaving much cleared 

 land, which has turned into grassy 

 savanna. The original biota, here too, 

 must have been profoundly disturbed. 

 The biologist must, however, bear in 

 mind the law of compensation, which 

 clearly applies in such cases. Many 

 of the species now found only in this 

 section of Costa Rica would not occur 

 there at all were it not for the changes 

 which have taken place. The third 

 exception is that part of the Caribbean 

 slope which has been cleared for banana 

 plantations and other types of agricul- 

 ture chiefly along the railway lines from 

 Puerto Limon to San Jose". Such culti- 

 vation is particularly disturbing in the 

 tropics, where very delicate adjustment 

 to minute variations in conditions can 

 alone explain the numerical abundance 

 of species and the scarcity of individ- 

 uals. Probably 50% of the original 

 avifauna, for instance, has disappeared 

 from such cleared areas, never to return, 

 and few indeed are the species which 

 replace them, chiefly certain native 

 ones which were able to adapt them- 

 selves to the sudden change in condi- 

 tions. Cultivation has been steadily 

 spreading and increasing in eastern 

 Costa Rica, but at least 75% of the 

 tropical rain forest is still a primeval 

 wilderness. There is no satisfactory 

 evidence that a single species of the 

 Costa Rican fauna is as yet in danger of 

 extermination, from causes which could 

 be ascribed wholly to the influence of 

 man. Consequently, while there are no 

 Preserves, none are as yet really needed. 

 No polluted waters of any consequence 

 are known. 



III. POLITICAL RELATIONS, TRANSPORTA- 

 TION AND OPPORTUNITIES FOR 

 RESEARCH 



There is probably no section of the 

 New World tropics which can be reached 

 so conveniently or so cheaply as Costa 

 Rica, or where greater diversity of con- 

 ditions exist. This is due to the com- 



