248 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13 



The Los Angeles County Museum Channel Islands Biological 

 Survey, begun in 1939, was the first attempt to study the complete 

 biota of the individual islands and to integrate the information thus 

 obtained for the island group as a whole. The author, acting as field 

 botanist for the Survey, made extensive collections on all the Channel 

 Islands. The problems arising in this work led to ecological studies 

 under the direction of the late Dr. Howard de Forest of the University 

 of Southern California. 



While incidental mention has been made of the general ecological 

 conditions, in the various taxonomic reports of the island flora, there 

 had been previously, no detailed or objective study. No descriptive 

 account of the vegetation as such had been given in either general or 

 specific terms. For instance it was not possible to know, from written 

 accounts, what types of plant associations were to be found on the 

 different parts of each of the several islands. 



At intervals geologic, topographic, and oceanographic surveys and 

 reconnaissances had been conducted in the insular area and several 

 reports have been made upon its geologic evolution. Nevertheless, 

 little attempt has been made to trace the effect of these physiographic 

 changes upon the development of the present flora of the islands, and 

 there has been also insufficient study of the affinities of the island flora 

 with the floras of adjacent regions. Accordingly this investigation was 

 undertaken to study the island vegetation, to investigate the distribution 

 and the affinities of the island plants, and to make inquiry into the 

 effects of the ecological agencies upon the island plant life and its com- 

 munities. The study of the environmental factors of these insular habitats 

 led the writer to select Santa Barbara Island as the most central for 

 quantitative and instrumental analysis. The period of study extended 

 from March 17, 1940 to April 22, 1942. 



Meteorological stations have been maintained, by different agencies, 

 for various periods during the past forty five years. However, there 

 had been previously, little or no attempt to correlate the results of 

 climatological studies with the characteristics of the present vegetation. 



Ten instrument stations were set up on Santa Barbara. The instru- 

 ments used were: standardized, spherical, Livingston porous black-cup 

 and white-cup atmometers for measuring evaporation and insolation, 

 anemometers, rain gauges, and maximum and minimum registering 

 thermometers. At two stations recording hygrographs and thermo- 

 graphs were used for obtaining a continuous record of humidity and 

 temperature. All of these instruments were modified or rebuilt to serve 



