Development of Ecosystem Research

Experimental studies established the major community-physiological processes that determine the structure, growth and biodiversity of overstorey and understorey plants and resident vertebrates in an ecosystem. These community-physiological studies were promoted internationally by the UNESCO Arid Zone Research Program, the International Biological Program (Sections Productivity, Production Processes and Conservation), the International Union for the Conservation of Nature and, finally, the International Geosphere-Biosphere Program that is studying the impact of Global Warming on the World's ecosystems. During the short period of annual foliage growth in evergreen plant communities, aerodynamic fluxes (frictional, thermal, evaporative) in the atmosphere as it flows over and through a plant community determine the foliage projective covers and leaf attributes in overstorey and understorey strata. These foliar attributes determine the community-physiological constant, the evaporative coefficient, of the plant community. An increase in air temperature of 2∘C during this period of annual foliage growth will affect the structure of the plant community, so that tall open-forests → open forests → woodlands → open scrub → low open-shrubland → desert communities. Variation in available soil water during this short period of annual foliage growth will influence vertical shoot growth but not foliage projective covers and leaf attributes produced in the overstorey stratum.