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M.S. Seminar – Angelina Haines

August 13 @ 9:00 am - 10:00 am

M.S. Seminar: Angelina Haines, Maj. Prof, Dr. Robert Gitzen

Title: What ignites fire ant density and impacts in longleaf pine ecosystems?

Location: Dixon Conference Room

Date: Monday, August 13, 2018

Time: 9:00 a.m.


Angelina Haines1,2, Christopher Lepczyk1, Robert Gitzen1, D. Clay Sisson2, and Theron Terhune II2

 1 Dept. of Wildlife Sciences, Auburn University, Auburn, AL
2 Tall Timbers Research Station and Land Conservancy, Tallahassee, FL

Title: What ignites fire ant density and impacts in longleaf pine ecosystems?

Invasive species are a widely recognized threat to global biodiversity. Invasive invertebrates are often a subject of study due to their impacts on human health, agriculture, and ecosystem function, but their impacts on local invertebrates are less known. An ideal model species to quantify this relationship is the red imported fire ant (RIFA, Solenopsis invicta). RIFA take advantage of disturbed landscapes to colonize and consequently compete with local invertebrates. This can be problematic for landscapes that require disturbance for restoration and maintenance, such as the longleaf pine ecosystems (Pinus palustris) of the southeastern United States. We sought to quantify what environmental variables were impacting RIFA density and their subsequent impacts on native and exotic ant biodiversity. Specifically, we hypothesized that RIFA mound density and forager abundance (i.e. level of activity) are driven by soil type, groundcover type, and time since burn. To test our hypotheses, we conducted line-transect mound surveys and pitfall trapping on 11 properties in Florida and Georgia managed with frequent fire. Pitfall trapping was used to estimate RIFA forager abundance and how their presence may influence general ant biodiversity, which is the subject of ongoing debate in the literature. Factors affecting mound density were investigated using a Poisson generalized linear mixed effects model, while the abundance of RIFA foragers and other ant species were analyzed with Poisson models and Akaike’s information criterion. Results indicate that RIFA mound numbers have a relationship to survey year, region, groundcover type, and time since burn. Significantly higher RIFA mound numbers were present in sites that have not been burned in a year and were historically agricultural. Analysis of pitfall trap data indicates that RIFA mound number also correlates with both native and exotic ant biodiversity. Specifically, as the number of RIFA mounds increase, native ant biodiversity decreases and exotic ant biodiversity increases. Our findings address an important gap in understanding how RIFA invasions and relate to restoration management and modern impacts of land use history.


August 13
9:00 am - 10:00 am
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