TheImprovement ofTropical and Subtropical Rangelands

THE SOOIAL OONTEXT FOR RANGELAND IMPROVEMENT 53
Runge, C. F. 1981. Common property externalhiee: Iaolation, uaurance, and
reaource depletion in a traditional gruing context. Amencuan Journal 0/
Agricultural Ecoraomiu 63:595-806.
Sail, A. 1918. Quel am'nagement putorrJ pour Ie Sahel. R4wc Ti." Mondl
19(13):161-169.
Thalen, D. C. P. 1919. EuJlow and rJAliRfion 0/ Dill" S1truI &n,llandl in Iraq.
Dr. W. Junk, The Hape, Netherlanda.
U.S. Department of Agriculture Foreat Service. 1919. &n,lland Policill/or tM
1bIun. Government Printing Office, Wuhineton, D.C., USA.
Wagner, F. J. 1983. Nomadic putoralism: Ecological adjustment to the reaUti.
of arid environment•• Paper preaented at the 149th Annual Meeting of t;he
American Auociat;ion for t;he Advancement; of Science, Det;roit;, Michipn,
USA.
Weat;ern, D. 1982. The environment; and ecology of paat;oraliat. in arid .avannu.
Dcwlopmmt and OIaange 13(2):183-211.