Effects of a tornado on birds in a Cross Timbers community


Tornados can influence forests by increasing openness of canopies and decreasing the frequency of large trees. These changes may indirectly influence the avian community; therefore, we monitored birds in a Cross Timbers community that had recently experienced an F3 tornado. We surveyed the avian community 6 times during summer of 2 years. We performed surveys along three transects in the impacted site, a nearby non-impacted site, and a grassland. Species richness and composition were significantly different among habitats, but these differences were not related primarily to damage by the tornado. A partial canonical-correspondence analysis suggested that differences among habitats were due to species segregating between habitats with trees (impacted and non-impacted forests) and those without trees (grassland). It appeared that the avian community did not respond strongly to impact of the tornado. We suggest that avian communities in relatively open and patchy forests, such as the Cross Timbers, will not respond as strongly to localized disturbance from wind as will communities in more mesic, closed-canopy forests. Open woodlands lack adequate habitat for species that occupy interiors of forests; these species are expected to segregate the strongest between impacted and non-impacted sites.

The Southwestern Naturalist, 55:460-466