Oral Presentations
Presentation Type
Presentation
Faculty Mentor’s Full Name
Victoria Dreitz
Faculty Mentor’s Department
W. A. Franke College of Forestry and Conservation
Abstract / Artist's Statement
Freshwater gastropods are important indicators of ecosystem health. Many native gastropod species are considered highly imperiled while other non-indigenous species are considered damaging invaders. Campeloma decisum, Pointed Campeloma, is a common freshwater gastropod from family Viviparidae found in varied habitats across the eastern United States and southeastern Canada. Our study sought to increase the knowledge on C. decisumusing geometric morphometric analyses to test which environmental factors may be driving shell shape variation. C. decisum (n = 458) and environmental data were collected from 22 sites in 6 lakes in central and northern Michigan. Specimens were photographed with apertures orthogonal to the camera lens and 26 landmarks were digitized onto each shell image to estimate shell and aperture shape. A Procrustes superimposition was performed to scale and rotate the shells to focus analyses solely on shape. Linear discriminant analyses (LDA) were run to quantify shape variation among the sites and lakes sampled. Correlations were tested for among environmental variables and LDA axes that defined shell shape. The LDA assigned 80.8% of snails to their site of origin and 90.6% to their lake of origin. Shell shapes of C. decisum were most strongly correlated with latitude, Secci depth, ammonia concentration, phosphate concentration, magnesium concentration, pH, alkalinity, and sand substrates. Higher ammonia and phosphate concentrations often correlated with more elongate shapes (i.e., taller spire). The pH at sites and lakes appeared to be a strong driver of spire decollation with more acidic conditions likely breaking down calcium carbonate in shells. In contrast to a previous study on the often sympatric freshwater gastropod Elimia livescens (family Pleuroceridae), our study found that lake fetch was not as clear of a driver of shell shape in C. decisum. We recommend collecting additional C. decisum specimens from lakes with longer fetch to expand the dataset and further effects of lake morphometry on shell shape. Understanding forces that drive the ecology and evolution of taxa guide the conservation and recovery of imperiled gastropods and provide insight for controlling the spread of non-indigenous species in a rapidly changing environment.
Category
Life Sciences
Identifying environmental drivers of shell shape variation in the freshwater gastropod Campeloma decisum
UC 330
Freshwater gastropods are important indicators of ecosystem health. Many native gastropod species are considered highly imperiled while other non-indigenous species are considered damaging invaders. Campeloma decisum, Pointed Campeloma, is a common freshwater gastropod from family Viviparidae found in varied habitats across the eastern United States and southeastern Canada. Our study sought to increase the knowledge on C. decisumusing geometric morphometric analyses to test which environmental factors may be driving shell shape variation. C. decisum (n = 458) and environmental data were collected from 22 sites in 6 lakes in central and northern Michigan. Specimens were photographed with apertures orthogonal to the camera lens and 26 landmarks were digitized onto each shell image to estimate shell and aperture shape. A Procrustes superimposition was performed to scale and rotate the shells to focus analyses solely on shape. Linear discriminant analyses (LDA) were run to quantify shape variation among the sites and lakes sampled. Correlations were tested for among environmental variables and LDA axes that defined shell shape. The LDA assigned 80.8% of snails to their site of origin and 90.6% to their lake of origin. Shell shapes of C. decisum were most strongly correlated with latitude, Secci depth, ammonia concentration, phosphate concentration, magnesium concentration, pH, alkalinity, and sand substrates. Higher ammonia and phosphate concentrations often correlated with more elongate shapes (i.e., taller spire). The pH at sites and lakes appeared to be a strong driver of spire decollation with more acidic conditions likely breaking down calcium carbonate in shells. In contrast to a previous study on the often sympatric freshwater gastropod Elimia livescens (family Pleuroceridae), our study found that lake fetch was not as clear of a driver of shell shape in C. decisum. We recommend collecting additional C. decisum specimens from lakes with longer fetch to expand the dataset and further effects of lake morphometry on shell shape. Understanding forces that drive the ecology and evolution of taxa guide the conservation and recovery of imperiled gastropods and provide insight for controlling the spread of non-indigenous species in a rapidly changing environment.