Planes, plains and food chains—Bottom up management of airport ecosystems

Background/Question/Methods

In general, airport properties encompass grassland, wetland, and managed turf habitat—all potentially attractive to wildlife.  The goal of this FAA supported project was to evaluate several native plants against a conventional turf mix for degree of wildlife attraction or deterrence. In the spring of 2009 replicate 232 M²plots of turf species were hydro-seeded at three airports located in Central NY. Vegetation cover, insect sweeps, bird counts and fecal pellet counts were conducted at each plot. Mammals were monitored with motion detecting infrared cameras (deer and coyote) and Sherman traps (rodents). A second study investigated relationships between grass height and bird presence at five airports in the eastern US.  Grass heights were categorized into a series of 10 cm groups and bird counts were conducted in point-count surveys.

Results/Conclusions

Indian Grass (Sorghastrum nutans) and  Little Bluestem (Schizachyrium scoparium produced good cover (up to 60%) approaching that of contractor’s mix (91%) and well above native grasses Poverty Oats (Danthonia spicata), Crinkled Hairgrass (Deschampsia flexuosa) and Thyme (Thymus pulegiodes) in the first season. Motion detecting infared cameras demonstrated that the contractor’s mix attracted significantly more feeding deer than an established plot of Indian Grass over a 2-month period (Χ² = 44, P<0.001). Fecal pellet count data from all airports followed the same pattern. Birds were preferentially attracted to plots of contractor’s mix and Thyme significantly more than the native grasses ( χ²=32.2, P < 0.001). Insect attraction to the native species plots was generally equal to or less than that of the contractor’s mix plot and varied greatly across the season.  In our second study, we found fewer birds present on airport property when grass height ranges between 31-40 cm, than where grass height is less than 31 cm (P=0.03).   These studies suggest that management of airport vegetation, particularly the grass, is paramount in minimizing the threat that wildlife poses to aviation.