View Static Version
Loading

Insect community responses following the summer 2018 fire at Altona Flat Rock State Forest in Altona, New York Heather Thompson

Background of Study

Altona Flat Rock State Forest, located in Altona, New York is characterized by a thin, infertile soil layer on sandstone pavement and a jack pine dominant canopy and blueberry and huckleberry understory. This landscape is uniquely fire prone for the region and the most recent fire occurred during the summer of 2018. Multiple studies have been done, or are currently being done at the Flat Rock to gain a better understanding of the native biota, and to see how the ecosystem responded to the fire. Relatively few studies have been done studying insect responses to disturbance events globally, so an opportunity arose to contribute to this literature, as well as increase our own understanding of the variety of insects found at Altona.

Photo: Amy T Bedard

Research Questions

1. Was abundance greater in 2018 or 2019?

2. Does community composition differ between the burn site and reference site?

3. Will the burn site have higher diversity than the reference site in either year?

4. Will community composition change at the burn site over time?

Methodology

Samples were collected using malaise traps at the 200 plot and 202 plot at Altona. The 200 plot was unburned in 2018, so it served as a reference site. The 202 plot was moderately burned and distanced from unburned areas so it was selected to study the impact. In 2018 traps were set on 8/16 and samples were collected on 8/23, 9/3, 9/12, and 9/28. In 2019 traps were set on 7/2 and samples were collected on 7/16, 7/30, and 8/21. The samples from 2018 have been identified to Order, but the 2019 samples will have Diptera identified even further, at least to Family. After identifying the 2019 samples I will revisit the 2018 Diptera samples to identify to Family as well.

Some groups identified so far

Preliminary Results

House flies (Muscidae) were the dominant taxa at both sites in 2018, and other Diptera were the second most abundant taxa. Neuroptera (net-wings) and Orthoptera (grasshoppers) are the least abundant taxa at both sites. Six of the nine taxa had greater abundance at the burn site. House flies peaked one week earlier at the burn site though other Diptera peaked a week later than it did at the reference site (Figures 3&4). Lepidoptera and Hymenoptera were much more abundant in early 2019 samples than 2018 samples (based on preliminary counts for 7/16 reference samples).

Fig 1. Total abundance at burn and reference sites (df=8, x^2=47.768, p value=0.0000001094).
Fig 2. Total abundance of all orders at the burned and unburned sites in 2018.
Fig 3. Changes in abundance as season progressed at reference site.
Fig 4. Changes in abundance as season progressed at burn site.

Predictions

Initially house flies and other Diptera will dominate at the burn in 2018, but following vegetative regrowth in 2019 other taxa will return and increase evenness. Overall, both sites will have a greater abundance of parasitic, predatory, and decomposer insects in both years, as this system is better suited for these functional groups due to its infertility. Detritivorous and ground insects will have low abundance at the Flat Rock overall, due to the shallow soil depth and thin litter layer.

Citations

Title Slide Fire Image: https://www.healthline.com/health-news/how-forest-fires-can-endanger-your-health-from-miles-and-miles-away

Insect Photos from Wikipedia, bugguide.net, (robber fly: Donna Brunet), whatsthatbug.com, (long-legged fly: magnified nature pinterest), (midge: Oscar Liburd)

Credits:

(included in citations)

NextPrevious