On my recent week-long collecting trip, the first three days were spent at Four Canyon Preserve in far northwestern Oklahoma. This nearly 4,000-acre preserve features a stunning landscape of rugged, wooded canyons dissecting ridges of mixed-grass prairie which provide critical habitat for several rare plants and animals. Despite years of overgrazing, fire suppression, and invasion by exotic plants, The Nature Conservancy (TNC) recognized the restoration potential of this landscape and began management practices to restore its ecological function and integrity after acquiring it in 2004. The land was rested until April 2008, at which time a wildfire swept through the area and burned approximately 90% of the property. This event was actually welcomed by TNC, who was already in the process of initiating a prescribed burn – they simply pulled back and let it rip! The burn, combined with mechanical removal of eastern redcedar (Juniperus virginiana) that had invaded many areas of the preserve, did much to confine woody growth to the canyons proper, and good rains during the past two springs following that burn have resulted in a lush, green, diverse landscape brimming with prairie wildflowers. The vivid contrast between the green vegetation and the red clay canyons with their white gypsum exposures has created spectacular vistas of a rugged landscape. This year, cattle have been reintroduced at low levels to simulate the irregular, patchy disturbance experienced in pre-settlement times when native grazers (bison and elk) dotted the landscape.
The flora (Hoagland and Buthod 2007) and avifauna (Patten et al. 2006) of the preserve are well characterized, but (as nearly always seems the case) arthropod and other micro faunas need much additional study. My hymenopterist colleagues and I were welcomed enthusiastically by TNC staff, who are anxious to incorporate the results of our insect surveys into an overall fauna. Apoid hymenopterans appear to have benefited greatly from the recent rejuvenation of the preserve’s floral character. Results for the beetle populations that I encountered, however, were more mixed. Certain groups, such as scarabaeine dung beetles, were quite abundant and diverse (due to the reintroduction of cattle), but others, including the tiger beetles, jewel beetles, and longhorned beetles that I was most interested in finding, existed at rather low and not very diverse levels. I had hoped to find the very rare Cylindera celeripes (swift tiger beetle) running amongst the clumps of vegetation on the preserve’s red clay exposures but instead saw only the ubiquitous Cicindela punctulata (punctured tiger beetle), and the few jewel beetles that I managed to beat off the lower branches of hackberry (Celtis laevigata) and soapberry (Sapindus saponaria var. drummondii) trees were found only in the small parts of the preserve that escaped last year’s burn. This seems fairly typical – I generally don’t find many insects in these groups whenever I survey areas that have experienced a significant amount of recent burning. Some ecologists might take exception to this statement, and they would have little difficulty citing studies that show rapid recolonization of prairies by a majority of prairie insect specialists within two years after a prescribed burn. Nevertheless, the impact of prescribed burning on invertebrate populations and its potential for causing local extirpations has become a contentious issue among ecologists and entomologists in recent years. While my experience hardly passes for rigorous investigation, I am becoming increasingly convinced that a certain amount of caution is warranted when designing burn management plans for prairie relicts.
I’ll discuss more about the beetles and other insects (and even some vertebrates) that I saw during my three-day visit to Four Canyon Preserve in future posts. In the meantime, I share with you some of my photos of this spectacularly beautiful landscape (note the abundance of woody cadavers from last year’s burn in some of the photos).
Hoagland, B. W., and A. K. Buthod. 2007. Vascular flora of the Four Canyons Preserve, Ellis County, Oklahoma. Journal of the Botanical Research Institute of Texas 1(1):655–664.
Patten, M. A., D. L. Reinking, and D. H. Wolfe. 2006. Avifauna of the Four Canyon Preserve, Ellis County, Oklahoma. Publications of the Oklahoma Biological Survey (2nd Series) 7:11-20.
Copyright © Ted C. MacRae 2009