TERRESTRIAL ENVIRONMENTS AND ECOLOGY 



193 



Fig. 3 a. Typical beach vegetation consists of Lepturus repena grass, the flowering 

 morning glory vine Ipomoea pes-caprae. and the single whorl of leaves and small white 

 inflorescence of the shrub Toumefortia argentea; b. The interior of the forest on Ikuren 

 Island in the early 1960s when the Pisonia grandis trees were still 8m2dl in the fore- 

 ground. Note the sprouting coconuts. [Photographs by E. S. Reese.] 



about the herptofauna and insects of the atoll. We know 

 essentially nothing of the role of the soil organisms 

 (Maguire, 1967). What little is known of the birds is sum- 

 marized by Berger (Chapter 13, Volume I, and Chapter 

 29, Volume U, this publication). We lack studies on the 

 behavioral and physiological ecology of the seabirds which 

 play such a profoundly important role in energy and nutri- 

 ent transfer between the marine and terrestrial ecosystems. 

 Only the land crabs and rodents were studied 

 thoroughly over a number of years. The research on the 



rats and mice of Enwetak is described by Jackson et al. in 

 this volume (Chapter 12). 



Land Crabs 



Land crabs and birds are the most conspicuous animals 

 of the atoll. Of the land crabs, those belonging to the Fam- 

 ily Coenobitidae, the land hermit crabs, are the most con- 

 spicuous. Bright red to brownish red adult Coenobita per- 

 \atus axe found on most of the islands. Usually the adults 

 are found in Turbo shells, while the younger, smaller crabs 



