182 



MISCELLANEOUS PUBLICATION 1271, U.S. DEPARTMENT OF AGRICULTURE 



microenvironment interactions, feeding back onto 

 regeneration of the plant community, were likely 

 to be of greatest importance in degeneration. 

 However, much needs to be done before our 

 knowledge of stock-microenvironment interac- 

 tions can contribute fully to the scientific man- 

 agement of Australian arid and semiarid range- 

 lands. In particular, man}^ of the interactions 

 identified in figure 2 need to be evaluated over 

 a wider range of situations. The way in which 

 the interactions are interrelated in particular 

 situations requires further clarification. Most im- 

 portantly, the implications of the altered micro- 

 environment need to be examined not only in 

 terms of plant and animal productivity, but also 

 in terms of plant community and species regener- 

 ation. 



Acknowledgments 



The technical assistance of R. Bawden, F. Fus- 

 sell, W. Gordon and K. Greaves in the collection 

 of much of the new information presented in this 

 paper is gratefully acknowledged. K. Greaves 

 also assisted in the computation of some of the 

 results and preparation of the line drawings. 



W. E. Mulham kindly supplied figure 1 and 

 C. J. Totterdel, figure 6. 



Finally. I wish to thank those colleagues at the 

 Riverina Laboratory who assisted by discussion 

 and by commenting on the manuscript. 



References 



(1) Anonymous. 



1901. report of royai. commission on the western 

 division of new south wales to inquire 

 into the condition of the crown tenants. 

 Pp. 5-25. Government Printer. Sydney. 



(2) Aase. J. K„ and .7. R. Wight. 



1970. ENERGY BALANCE RELATIVE TO PERCENT TLANT 

 COVER IN A NATIVE COMMUNITY. J. Range 



Mangt. 23: 252-255. 



(3) Alderfer, R. B.. and R. R. Robinson. 



1947. RUNOFF FROM PASTURES IN RELATION TO GRAZ- 

 ING INTENSITY AND SOIL COMPACTION. .7. Amer. 



Soc. Agron. 39 : 948-958. 

 (4 1 Anderson, D. .7. 



1970. ANALYSIS OF PATTERNS IN ATRIPLEX VESICARIA 

 COMMUNITIES FROM THE RIVERINE PLAIN OF 



new south wales. Pp. 63-68. In Jones, R. 

 (ed.) The biology of Atriylex, C.S.I.R.O. 

 (Australia), Division of Plant Industry. Can- 

 berra 



(5) Ashby, \V .C, and N. C. W. Beadle. 



1957. studies in iialophytes. hi. salinity factors 

 in the growth of australian saltbushes. 

 Ecol. 28 : 344-352. 



(6) Bailey, A. W. 



1970. BARRIER EFFECT OF THE SHRUB ELEAGNUS COM- 

 MUTATA ON GRAZING CATTLE AND FORAGE PRO- 

 DUCTION in central alberta. J. Range Mangt. 

 23: 248-251. 



(7) Barrow. N. J. 



1961. MINERALISATION OF NITROGEN AND SULPHUR 



from sheep faeces. Austral. J. Agric. Res. 12 : 

 644-650. 



(8) 



1969. IMPLICATIONS OF STOCKING RATE EXPERIMENTS 

 — NUTRIENT REQUIREMENT AND FERTILIZER 



requirement. Proc. Austral. Grassld Conf. 

 (1968) 2: 169-171. 



(9). Beadle. N. C. W. 



1948a. the vegetation and pastures of western 



NEW SOUTH WALES WITH SPECIAL REFERENCE TO 



soil erosion. Government Printer, Sydney. 

 281 pp. 



(10) 



(11) 



1948b. studies in wind erosion. J. Soil Conserv. 

 Serv. N.S.W. 4 : 30-35, 64-68, 123-134, 160-170. 



— and Tchin, Y. T. 



(12) 



1955. nitrogen ECONOMY IN SEMIABID plant com- 

 munities. 1. THE ENVIRONMENT AND GENERAL 

 consideration. Proc. Linn. Soc. N.S.W. 80: 

 62-70. 



— Whalley. R. D. B., and .7. B. Gibson. 



1957. studies in halophytes. II. analytic data 



ON THE MINERAL CONSTITUENTS OF THREE SPE- 

 IES OF ATRIPLEX AND THEIR ACCOMPANYING 



soils in Australia. Ecol. 38 : 340-344. 



(13) Black, J. M. 



1943-1957. flora of south Australia. 2nd Edi- 

 tion. Government Printer. Adelaide. 



(14) Charley, J. L. 



1959. SOIL SALINITY — vegetation patterns in west- 

 ern NEW SOUTH WALES AND THEIR MODIFICA- 

 TION by overgrazing. Ph.D. Thesis, Univer- 

 sity of New England. Armidale, Australia. 

 274 pp. 



(15) and S. L. Cowling. 



1968. CHANGES IN SOIL NUTRIENT STATUS RESULTING 

 FROM OVERGRAZING AND THEIR CONSEQUENCES 

 IN PLANT COMMUNITIES OF SEMI-ARID AREAS. 



Proc. Ecol. Soc. Austral. 3: 28-38. 



(16) Condon, R. W., J. Newman, and G. Cunningham. 



1969. SOIL EROSION AND PASTURE DEGENERATION IN 

 CENTRAL AUSTRALIA. PARTS I-IV. J. Soil Con- 



serv. Serr. N.S.W. 25 : 47-92, 161-182, 225-250, 

 295-321. 



