Date of Award

Spring 5-3-2024

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Entomology

Advisor

Allison Gardner

Second Committee Member

Thomas Rounsville

Third Committee Member

Angela Mech

Abstract

Mosquito-borne diseases are a serious public health concern worldwide. There are many important mosquito vector species inhabiting forested ecosystems; timber harvesting may play a role in altering the abundance of vector species. Timber harvesting is an activity within the broader field of silviculture. Silvicultural treatments are defined as a plan that combines specific harvesting, regeneration, and tending methods to improve the conditions of the forest stand. Utilizing forest management techniques can influence mosquito vectors by reducing their population and transmission risk to humans. Additionally, silvicultural treatments can alter the diversity or abundance of adult mosquito species through a variety of mechanisms, such as heavily harvested stands may have fewer tree holes, and suitable aquatic habitat availability, providing habitat for developing mosquito larvae. The goal of this study was to analyze the response of adult mosquito abundance and species diversity to selected silviculture treatments. This study selected three types of silviculture treatments (i.e., thinning, overstory removal, and shelterwood establishment cut) and two types of control treatments (i.e., softwood with no recent harvest and hardwood with no recent harvest). This project is novel in the types of treatments being observed and the location of the study. This study has three main objectives. First, this study aims to assess the mosquito abundance and species diversity across five treatments: 1) hardwood stand with no recent harvest, 2) softwood stand with no recent harvest, 3) softwood stand with thinning, 4) softwood stand with overstory removal, and 5) softwood stand with shelterwood establishment cut. Second, this study aims to assess stand characteristics (e.g., canopy closure, sapling count, and tree species composition) to predict mosquito abundance and diversity within each stand. Third, this study aims to assess if timber harvesting alters the understory microclimate and aquatic habitat availability with consequences for mosquito abundance, as well as other potential mechanisms to explain variation in mosquito communities across treatments. Adult mosquito surveillance was conducted in the Dwight B. Demeritt Experimental Forest from 6 June to 23 August 2022. Light and infusion-baited gravid traps were deployed to collect a diversity of adult mosquitoes in 13 forest stands across five treatment categories. A total of 5,079 adult female mosquitoes were collected. Mosquitoes were the most abundant in the hardwood with no recent harvest treatment. The most abundant species was Coquillettidia perturbans accounting for (76.43%) of total mosquitoes captured, followed by Ochlerotatus japonicus accounting for (5.31%), and Culex spp. accounting for (4.13%). Cq. perturbans and Oc. japonicus populations were lower following a timber harvest. This may present a lower risk of contracting mosquito-borne diseases. In contrast, the Culex species did not exhibit a direct response to the silviculture treatments. Various abiotic factors such as tree holes, wind, leaf detritus, and aquatic habitat availability likely influenced the abundance of Cq. perturbans within hardwood stands. The results of this analysis serve as a valuable resource for landowners aiming to reduce mosquito abundance and minimize the risk of vector-borne disease on their property. This research outlines forest management strategies required to decrease mosquito populations effectively.

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