A proposed mechanism for the formation of ‘Fertile Islands’ in the desert ecosystem

Abstract

Movement of nitrogen atoms throughout the environment occurs by (1) physical transport such as molecular diffusion and hydrodynamic flow, mechanisms that always disperse and (2) biological transport such as sap flow and animal movement, mechanisms that most often lead to concentration. Both types of transport are accelerated by moisture, but the physical mechanisms are more sensitive. In the desert ecosystem, micro-, meso-, and macro-fauna are all attracted to the canopies of whatever plants exist, the place of highest moisture, lowest daytime temperature and most abundant food sources. This paper presents the hypothesis that under conditions of desert aridity the concentrating biological transport mechanisms dominate over the dispersive physical mechanisms. This causes the phenomenon known as ‘fertile islands.’