PLEISTOCENE ECOLOGY AND BIOGEOGRAPHY 395 



hunting-gathering people who did not prey on large animals. Fluted 

 points may be an independent New World invention ; they have not 

 been found with paleohthic sites in Siberia (Wormington, 1957). 



In South America early man had arrived at least by early Post- 

 glacial time as is demonstrated by the well-known association of 

 man and sloth at Palli Aiki Cave, Chile. Cruxent and Rouse (1956) 

 and Rouse and Cruxent (1957) report Paleo-Indian sites in northern 

 Venezuela. 



From the biological viewpoint it does not seem necessary to enter 

 the Interglacial man controversy. If the Tule Spring site, Nevada, is 

 correctly dated at older than 23,800 years, it clearly indicates that 

 prehistoric man arrived before the Wisconsin maximum of 17,000 

 years ago. Presumably this would require arrival in Alaska, at least 

 by early post-Sangamon time, of a people whose economy was 

 specialized for hunting large animals in treeless tundra. It seems 

 easier to establish a trans-Bering population in southern Alaska 

 than to understand how, during the Wisconsin glacial period, such a 

 population spread south through what is mapped as glaciated 

 terrain. 



For the ecologist and biogeographer one point remains clear. 

 From the time of man's arrival we may assume a radical change in 

 fire frequency. In the strict sense, theoretical climatic climax vegeta- 

 tion in savanna and grassland areas (Stewart, 1951, p. 319), and 

 even in parts of the Eastern Deciduous Forest, cannot postdate 

 man's arrival. In addition to savannas many areas of temperate 

 forest may have been greatly modified and subcHmax, consolidation, 

 or even pioneer species favored at the expense of those typical 

 only of climax positions in plant succession. The paleoecological 

 dilemma posed by the B zone pine pollen period (Dansereau, 1953) 

 may be resolved in terms of an archaeological disclimax controlled by 

 early man. There is no longer much doubt about his presence in the 

 East at that time. 



LATE PLEISTOCENE EXTINCTION 



In the words of Darwin : " It is impossible to reflect on the changed 

 state of the American continent without the deepest astonishment. 

 Formerly it must have swarmed with great monsters; now we find 

 mere pigmies, compared with the antecedent allied races." {Voyage 

 of the Beagle, 1855, p. 222). In the hundred years since Darwin wrote, 



