native herbivores such as Black-tailed Jackrabbit 

 and Great Basin Pocket Mouse, which tend to be 

 more abundant on ungrazed sites (MacCracken 

 and Hansen 1982, Verts and Kirkland 1988). 

 Moderate to heavy livestock grazing reduces 

 habitat quality for Grasshopper Sparrow (Saab et 

 al. 1 995, Vickery 1 999) by removing nesting 

 cover On the other hand, this type of grazing may 

 benefit Long-billed Curlew and more common 

 species like Homed Lark by reducing vegetation 

 height and cover if grazing occurs before the onset 

 of nesting (Paige and Ritter 1 999). In the 

 Sandhills area, nesting commences for many bird 

 species before cattle are introduced (personal 

 observation). 



Heavy grazing should benefit tiger beetle species 

 associated with early-seral disturbance by creating 

 more early and mid-seral habitat. Lesica and 

 Cooper ( 1 999) suggested that heavy grazing will 

 also help maintain early-seral vegetation on slopes 

 where trampling in significant. However, livestock 

 can destroy tiger beetle larvae by trampling their 

 burrows (Knisley and Sdchultz 1 997), especially if 

 livestock are concentrated in small areas or are 

 grazed at high densities. 



As with fire, grazing is most beneficial and usefii 

 as a management tool when it creates a mosaic of 

 cover types and disturbance regimes. The most 

 reasonable grazing system for the Sandhills is 

 probably some form of rest or deferred rotation 

 grazing (Saab et al. 1 995 ), where portions of the 

 Sandhills are left undisturbed while others are 

 grazed. These grazing systems distribute the 

 disturbance across the landscape in an uneven 

 pattern. Currently, early-seral habitat is most 

 abundant in the West Hills where grazing and 

 disturbance is also greatest. There is an obvious 

 correlation here between grazing and the presence 

 of early-seral vegetation in the Sandhills. 



Concluding remarks 



Lesica and Cooper ( 1 999) recommended that 

 prescribed fire be used every 20-30 years to 

 remove bunchgrasses and sagebrush in patches of 

 some unspecified patch size. Controlled fire 



followed by intense livestock grazing for 1-2 years 

 could significantly reduce vegetation cover, 

 reinitiating blowout development in the East Hills 

 and maintaining successional dynamics in the West 

 Hills. Through use of natural and controlled fire 

 and grazing, early-seral conditions to which the 

 rarest species are linked should increase in the 

 Sandhills. This approach appears most appropri- 

 ate for sandhills invertebrates and small mammals, 

 such as tiger beetles, shrews, and pocket mice, 

 with specific small patch requirements. However, 

 as Lesica and Cooper ( 1 999) prudently pointed 

 out, their recommendations should first be tested 

 by means of replicated demonstration areas 

 spread through the Sandhills. Demonstration 

 areas would be used to determine the relationships 

 between scale, fi^equency, and intensity of distur- 

 bances that will maintain the mosaic of early- to 

 late-seral vegetation "capable of supporting the fioll 

 spectrum of native species (Lesica and Cooper 

 1999, p. 300)." 



We concur with the suggestions of Lesica and 

 Cooper ( 1 999), with an additional comment. The 

 most effective management program will also 

 involve coordinating the activities of all owners 

 (Fish and Wildlife Service, Bureau of Land Man- 

 agement, State, and Private) with lands in the 

 Sandhills, as the entire site should be managed as 

 an integrated unit with a unified goal. Extending 

 this reasoning one additional step, the Sandhills 

 should also be managed as but one unit, albeit 

 unique, within the larger sagebrush-grassland 

 system of the entire Centennial Valley. 



Future work 



It remains to be determined how unusual the 

 Sandhills fauna is for the entire Centennial Valley, 

 especially the distributions and associations of 

 invertebrates, small mammals, and songbirds, as 

 few concentrated surveys have been conducted 

 elsewhere in the valley. We therefor recommend 

 additional surveys for sagebrush obligate and 

 grassland associated vertebrates (e.g.. Sage 

 Thrasher, Brewer's Sparrow, Grasshopper 

 Sparrow, Preble's Shrew, Great Basin Pocket 

 Mouse, Pygmy Rabbit) and invertebrates (e.g.. 



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