RECOMMENDATIONS 431 
greatly by the fullest possible use of vegetation studies, specifically 
by the consideration of the role of vegetation as a factor in the 
hydrology of dry lands and plant species and communities as 
indicators of climates, past and present. 
18. Further attention should be given to the study of the geo- 
morphic dynamics of landscapes for application to regional and 
land-type appraisal and land-use planning. 
Also see recommendations 13, 21, 25, 28, and 30(i1). 
Biology, Ecology, and Conservation 
1g. Intensive studies of the microclimatic environments of 
plants and animals should be encouraged and pursued. The rela- 
tionships between the data usually recorded by meteorological 
stations and the microclimatic effects of these phenomena in 
different sections of typical arid environments should be subjected 
to intensive study. 
20. Research on plant and animal ecology, improvement, and 
management in arid areas should be intensified. Emphasis should 
be placed on preadapted species and races, on understanding of the 
physiological factors in the selection of characteristics desired in 
breeding, on water requirements of the various species and breeds 
as related to production, and on utilization of available soil and 
climatic resources by plants and of available vegetation by various 
species and breeds of animals. 
21. Additional research is needed on the methods of determina- 
tion and the estimation of the water requirements of plants in 
arid regions, especially on the efficiency of transpiration, the rela- 
tionship between transpiration and photosynthesis, and the regu- 
lation of transpiration. The suggestion is made to the UNESCO 
Advisory Committee on Arid Zone Research that it compile a 
review of information and research studies currently available on 
this subject. 
22. Intensified research should be undertaken, and research 
results should be applied in the management of grazing, because 
of the paramount importance of grazing management in the con- 
servation and improvement of arid grasslands. 
23. A thorough investigation should be made of indigenous 
