Sul Ross State University
A Member of the Texas State University System

Insect Abundance in Response to Fire in Trans-Pecos Texas

by Scott Krueger, Robert J. Kinucan and Louis A. Harveson

A winter burn was conducted at Elephant Mountain Wildlife Management Area, Brewster County, Texas to investigate the effects prescribed burns have on insect recovery rates and abundance.

Insects and arachnids were collected from January-December 1997 using a D-vac suction machine. They were dried, weighed and identified to the familial level.

No differences (P< 0.05) were detected among insect and arachnid numbers and biomass prior to the burn. Following the burn, differences in numbers were detected among the arachnids and in nine of 15 insect orders, with greater numbers occurring in the control (unburned) site.

Biomass differed for the Hymenoptera, Orthoptera and Psocoptera. Insect and arachnid community growth rates were highest in the treatment site, with April-July having the largest growth rate.

Vegetation was sampled from December 1996-December 1997 by growth forms (i.e., grass, forb, shrub) using the canopy coverage method. Prior to the burn, the control site had more shrub cover (P = 0.048). Following the burn differences occurred for all growth form attributes except for shrub and grass basal cover.

At the current growth rates the results of this study indicate that insect populations would likely recover within 2-1/2 years following a winter burn.

Cooperative funding by Sul Ross State University and the Houston Livestock Show and Rodeo.