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Abstract

This study investigated the distribution, abundance, and biology of Cicindela limbata albissima Rumpp, an endemic tiger beetle known only from the Coral Pink Sand Dunes (CPSD) in southwestern Utah. A recently implemented conservation agreement between BLM, USFWS, Utah State Parks, and Kane County protects most of the known habitat of this beetle from off-highway vehicle (OHV) use. A search of collection records and field surveys of 19 Great Basin sand dune sites indicated that this species occurs only at CPSD. Yearly index counts of adults (1992–1998) during peak season in May ranged from 331 in 1997 to 895 in 1993, but the actual population size is probably 2–3 times higher than the index counts. Nearly all of the population is found in the primary habitat, a 300-m-wide × 2.7-km-long area in the southern part of the dune field. Small numbers of adults and larvae have been found at the far north end of the dune field.

Mark-recapture studies indicated that most adults moved only short distances (<300 m), but a few moved 1000 m. This beetle has a 2-year, modified spring-fall life cycle. Adults are most abundant from April through early June, but some adults from the following years adult cohort emerge and can be found from late August to early October. Adults are active on warm or sunny days, but they dig burrows which they use at night or during unfavorable weather. We observed little evidence of parasitism or predation of larvae or adults, but these limiting factors were not fully studied.

Surveys of dominant plant species, arthropod (potential tiger beetle prey) abundance, and OHV activity indicated that these vary throughout the dune field and may explain, in part, the distribution of C. l. albissima. The primary habitat is a transition area between the highly dynamic south end of the dune field and the more stabilized north end. Psoralidium lanceolatum Rybd., Sophora stenophylla Gray, and Stipa hymenoides R.&S. are the dominant plants in the interdunal swales of the primary habitat, but other species are dominant in other parts of the dune field. Numbers of arthropod individuals and taxa are greatest in the primary habitat. Off-highway vehicle activity was greatest at the south end of the dune field and lowest at the far north end. Run-over trials and observational data revealed that adult beetles are killed by OHVs, but more important impacts may be damage to vegetation, reduction of arthropod prey of C. l. albissima, and disturbance and increased desiccation of the larval microhabitat. We anticipate that the conservation agreement will provide long-term protection for this species at CPSD.

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