Conservation Ecology of the Texas Horned Lizard ('Phrynosoma Cornutum'): Comparative Effects of Summer and Winter Burning

Department of Natural Resource Ecology and Managemen

Red Imported Fire Ants: Impact on Biodiversity

The red imported fire ant, Solenopsis invicta Buren (hereafter referred to as imported fire ant), long considered a regional problem, is receiving renewed attention nationwide, with infestations found in Arizona, Maryland, Nevada, New Mexico, and Virginia (Mitchell 1996). Recently, infestations discovered in several regions of California caused great public concern (Brennan 1999, Schrader 1999). Initially, infestations appeared to be isolated in almond groves in Kern County; presumably these infestations originated from bee hives transported interstate for the purpose of pollinating crops. Separately, ornamental plants arriving in Las Vegas, NV, were infested with fire ants, and records showed that the point of origin was a nursery in Orange County, CA. Further inspections revealed infestations in over 16,000 acres of Orange County. Finally, infestations were identified in some desert irrigated agricultural regions of the Coachella Valley in Riverside County, CA. Subsequently, a toll-free telephone number was established for reporting fire ant mounds in the state of California (800-491-1899)

An annotated check list of the amphibians and reptiles of Colorado

Mode of access: Internet

Assessing landscape-level impacts of red imported fire ants on native faunal communities in pine-dominated forests

Since the accidental introduction of red imported fire ants (Solenopsis invicta Buren, RIFA) into Mobile, Alabama in the 1930’s, the invasion of this species into other areas across the southeast has increased drastically. RIFA have been implicated in the disruption of ecosystems and decreases in biodiversity. Most research on effects of RIFA on vertebrates and invertebrates have focused on small spatial scales and single species. I examined established populations of RIFA in relation to native ground-dwelling arthropods and small mammal communities in longleaf-pine and pine-hardwood forests. I evaluated the efficacy of using Amdro® to control RIFA and determined the effect of RIFA predation on arthropod and small mammal communities. RIFA suppression occurred in April, August, and October 2003. In the longleaf-pine forest, RIFA suppression was effective in June between years (P = 0.088) and treatments (P = 0.093). This was consistent with an increase in cotton mice abundance on treated (17.7 ± 2.7) versus control (6.0 ± 2.5) plots (P = 0.035), with 90% of cotton mice captured during the June sampling period. Across seasons, significant differences were observed for Collembola in August between years (P = 0.001) and in December between treatments (P = 0.01). Likewise, abundance of Coleoptera was greater in December between years (P = 0.023) and in May between treatments (P = 0.002). In the pine-hardwood forest, RIFA suppression was effective in April and June (P = 0.001, P = 0.004, respectively) when compared across seasons. No significant differences were observed for any small mammal species captured in the pine-hardwood site. Acari were greater on treated (11.0 ± 1.7) than control (4.7 ± 1.9) plots (P = 0.067); however, no significant differences were observed for any invertebrate group across seasons. Although this study is in the initial phase of a 5-year project, the data suggests that RIFA may potentially affect the abundance of selected faunal species in forested ecosystems

III. The Predaceous Enemies of Ants

The various means by which Nature prevents an excessive increase of the species not only forms in itself an interesting chapter of ecology, but its study is also of great importance in an understanding of the true meaning of Natural Selection. In the case of ants it has been contended that they are better defended than other insects against the attacks of predatory animals. Poulton evidently takes this for granted when he considers that ants, together with wasps, are among the favorite models for mimicking insects and other arthropods. These ant-like arthropods, having acquired by Natural Selection their resemblance to the aggressive, abundant, and well-defended ants, would according to this theory escape many of the attacks of their deceived and disgusted predaceous enemies. Though the evidence presented in the following pages is still very fragmentary, I trust the reader may easily conclude for himself to what extent such resemblances, which, in some cases at least, can hardly be doubted, have a real protective value. There is certainly little or no evidence to show that, as the theory is often expressed, ants are unpalatable to most insectivorous animals and are merely eaten accidentally or during the time in which young birds or other animals are learning what to eat with impunity and what to reject

Impacts of red imported fire ants (Solenopsis invicta Buren) on native faunal communities in two pine-dominated forests

Impacts red imported fire ants (RIFA) exert on native faunal communities were monitored in two pine-dominated ecosystems in Louisiana. After suppression of established RIFA populations with Amdro®, cotton mice (Peromyscus gossypinus), herpetofaunal, ground-dwelling invertebrate, Lycosidae, and non-target ant communities were compared between untreated-control and treated plots with respect to possible ecological impacts of RIFA on these communities. Efficacy of Amdro® (A. I. 0.7% hydramethylnon) was tested at Alexander State Forest and Sandy Hollow WMA, and was found to be effective at both sites for 99-42.3% and 97-48%, respectively, suppression of RIFA on treated plots, for three to seven months, with treatments administered in the evening at a rate 1.68 kg/ha. Following suppression, RIFA were shown to minimally impact cotton mice, ground-dwelling invertebrate populations, and Lycosidae species, indicating that RIFA is not the regulating factor in these communities. In the case of cotton mice, habitat conditions that favor cotton mice may also favor RIFA. The majority of non-target ants analyzed at Alexander State Forest and Sandy Hollow WMA also seem to coexist with RIFA, although some species including Aphaenogaster rudis-texana, Crematogaster lineolata, Brachymrymex musculus, Paratrechina faisonensis, Pheidole dentata, and Pheidole metallescens may occur in sparse, small populations in the presence of RIFA. At Alexander State Forest, both Brachymrymex musculus and Tapinoma sessile showed a positive response to RIFA suppression, indicating signs of competitive release. At Sandy Hollow WMA Monomorium minimum and Prenolepis imparis responded negatively to treatment, indicating that Amdro® may exhibit non-target effects to these two species. Herpetofaunal communities, particularly ground skink and southeastern five-lined skink populations may be negatively impacted by RIFA. However sample sizes for all herpetofauna species were low. Amdro® is effective at suppressing RIFA populations in forested ecosystems; however the impacts RIFA pose on native ground-dwelling faunal communities may be minimal in these two pine-dominated communities