THE OOLDEN TKOT^T. 39 



TEMPERATURE CONDITIONS IN THE KERN RIVER REGION. 

 I'.y ((. P. .Iknk-ins. 



The triliiitiiries of the upper portion of the upper Kern River tind their sources 

 iiinid ridocs nnd peaks of a high altitu(h> \\ liich tlirough a great part of the year 

 are covered with snow. The melting of the snow furnishes the streams with their 

 water supply. Even during the summer the supph' of snow is not entirely exhausted, 

 and where such is the case the springs whose reservoirs were tilled from the melting- 

 snow furnish the sti'eams with a constant supply of cold water, the temperature of 

 which the short period of warmth through the middle of the day does not markedly 

 ati'ect. Even in midsummer at these altitudes the nights are cold, the temperature 

 often falling .several degrees below the freezing point of water. During the day the 

 sky is more frequently overcast than is the case in most parts of California, and in 

 the highest altitudes light falls of snow ai"e not uncommon. Although these latter 

 usual!}- quickly disappear they add their contribution of cold water to the streams. 

 These conditions insure a comparatively low tempei'ature for the waters of the 

 tributaries of the upper Kern for the whole year. 



The tributaries of the Kern, however, all make great and rapid descent to the 

 Kern River. This river also continues to drop rapidly through mountain and foot- 

 hill regions until it reaches the plains. Through a comparatively short distance 

 waters from melting snows on the summit of Mount Whitney pass by Whitney 

 Creek and the Kern River, in summer from the temperature of melting snow to the 

 plains below where the temperature reaches a point exceeded by few places in the 

 United States. In these lower regions the waters of the river are not reinforced by 

 rains or springs and are unprotected by shade of vegetation. Indeed in this region 

 in summer the waters of the Kern are tinally lost by absorption and by evaporation 

 after breaking up into numerous winding streams. In recent times the distribution 

 of these waters is much modified by the great irrigation systems that are developing 

 along the Kern. The natural features thus noted bring about conditions of tempera- 

 ture which make the upper Kern with its tributaries lying in the mountains ideal for 

 trout, while during a great part of the year they render the lower portions of the 

 river living among the lower foothills and in the plains impossible for this fish. 



The land animals and plants along the banks of these streams have been studied 

 by the members of the Biological Survey. The changes in fauna and flora from the 

 .summit of Mount Whitney to the plains about Bakersfield include the extremes to 

 be found in the United States. In its descent from Mount Whitney the water passes 

 successively' the zones that have been designated Boreal, Transition, Upper Sonoran, 

 and Lower Sonoran by the Biological Surve}'. No like stud}' of the water forms of 

 animal and plant life of the streams of this region has been made, but from the nature 

 of the conditions no such well-marked zones could be looked for among the aquatic 

 forms as have been found for the terrestrial species. Nevertheless, a careful study 

 throughout could not fail to bring out interesting facts of the distribution of the 

 forms belonging to the streams. As it is, we do not at the present know accurately 

 the lower range of the trout, the farthest upper range of the tishes peculiar to the 

 lower portions of the stream, nor tiie range of any of the other animals that live with 

 them. 



