
Table 1.--Weather summary from Webster, South Dakota, 1901-38 
(U.S.D.A. (1941); 16 miles from the study area] 
January average temperature . 2... . + «© «© © eo » 9.2°F. 
July average temperature «.« « « o « © © «© » © © » » 70.1°F. 
Maximum temperature . . 2 + 6 6 ee © ee ee we 108°F. 
Minimum temperature .« . «se © ee es ee we Yor, 
Average last killing frost in spring .... «es May 16. 
Average first killing frost in fall ...... . . Sept. 25. 
Average growing season « « « 6 «© © © © © © © © «© © 132 days. 
Table 2.--Precipitation in vicinity of study area, by months, 1950-53 
[In inches. January 1950 - April 1951 from Webster, S. Dak., weather 
station; May 1951 - April 1952 from Roslyn weather station; May 1952 - 
December 1953 from Waubay National Wildlife Refuge weather station. ] 





. hevear 1901 +53 
1950 1951 1952 1953 average average 
January 0.89 0.33 0.82 1.45 0.87 O48 
February 05 86644 61.625 =i 0 261 48 
March Lee7: ORT.  W55e. “23 »79 085 
April -76 .89 .87 3.92 ‘161. 1.87 
May 2,0 2517 -L.6i" 2.67 2.43 2.61 
June 98 3.91 4.41 6.84 4 ok " 3.82 
July 6.37 3.98 1.90 2.85 3.78 3.09 
August 2.56 2.60 .39 1.83 1205 3eH1. 
September 1.17 .45 .51 415 257 2.19 
October 1.39 2.75 <O01, 45 Tel 1.34 
November Gi Oe ioe alco 79 eis 
December 39° VIWO3) 2 T55= “659 64 oT 
Total 19.61 19.85 13.68 23.32 19.13 21.01 
Upland vegetation 
The native upland vegetation of the region is true prairie as described 
by Weaver and Clements (1938) and consists mainly of midgrasses such as 
porcupine grass (Stipa Ss artea), dropseed (Sporobolus asper and S. hetero- 
lepis), little bluestem (Andropogon scoparius), prairie June grass(Koeleria 
cristata), bluestem wheatgrass (Agropyron smithii), and sideoats grama 
(Bouteloua curtipendula). On some pastures and high areas there are some of 
the short-grass species such as blue grama (Bouteloua gracilis) and buffalo 
grass (Buchloe dactyloides). In addition, some of the hay land has been 
seeded to introduced species. In some locations, particularly on steeper 
slopes, wolfberry (Symphoricarpos occidentalis) is dominant. Tree growth is 
limited to a few willows (Salix SPDs), cottonwoods (Populus deltoides), and 
occasional aspens (Populus tremuloides) on lowland sites, and to a few 
planted wocdlots. 

