The effects of prescribed fire on insect diversity in the Missouri Ozark highlands

Background/Question/Methods

Fire has long played a role in the dynamics of the unique forest ecosystems of the Missouri Ozarks. In contemporary forests, these applied disturbances are being used to mimic the historic fire disturbances found in the area and create a more open understory which promotes populations of wild turkey.  Because limited data is available regarding the relationship between ground dwelling arthropods and methods of prescribed fire in the Missouri Ozark Highlands, we wanted to examine the effects of different prescribed fire treatments on insect diversity in Little Black Conservation Area.  Pitfall traps were used to collect samples of ground-dwelling insects within three treatments: burn plots, unburned island plots and control plots. Each treatment had three plots that contained three pitfall traps. All of the traps were filled with propylene glycol and were left to collect for seven days.  After collection, we took the pitfall traps to the University of Missouri for further analysis. Each pitfall trap was sorted, insects were identified to order, family and subfamily and all other arthropods were identified to class. All specimens were pinned or put in vials and labeled with their scientific name and the trap number that they were removed from.

Results/Conclusions

After classifying the contents of the pitfall traps, we determined that a total of 2,211 specimens were collected. The classifications spanned across five classes: Insecta, Arachnida, Diplopoda, Chilopoda and Nematoda. Within the class Insecta, we found 12 orders and 43 families of insects. Regardless of treatment, each pitfall trap contained insects from two ant subfamilies, Myrmicinae and Formicinae, as well as Collembola and other arthropods in the class Arachnida. Overall, arthropods in the class Arachnida were more abundant in the control treatment compared to the burn and island treatments, while insects in the order Hymenoptera were more abundant in the burn plots and island plots compared to the control plots. Other orders in the class Insecta, such as Blattodea, Collembola and Orthoptera, were more abundant in the control plot, while Coleopterans and Dipterans were more abundant in the island and burn plots, respectively. More research is needed to better understand the effects of prescribed fire on ground-dwelling arthropods, specifically crickets and beetles, which are a key dietary component of wild turkey. Additional data should be collected pre-and post-burn for each treatment type and during years without drought so as to limit the error caused by other environmental factors.