Date of Award

Spring 2025

Project Type

Dissertation

Program or Major

Biological Sciences

Degree Name

Doctor of Philosophy

First Advisor

Brittany M Jellison

Second Advisor

Jason S Goldstein

Third Advisor

Jan A Pechenik

Abstract

Climate change is thought to favor invasive species and harm native species, but the native slipper limpet, Crepidula fornicata, may prosper under climate change scenarios. C. fornicata is widely distributed along the East Coast of the United States and has been known to increase its reproductive output in response to warming water temperatures. This species is an ideal model organism for studying the impacts of climate change because this species has a large latitudinal distribution, are very common, and are present in many different ecosystems. However, little is known about C. fornicata population dynamics, trophic relationships, or population level differences with respect to its morphology and physiology. In this dissertation I aim to understand the ecological role of this species, how it interacts with the community, and if there are population level differences in morphology and physiology.In my first chapter, we quantified the abundance and distribution of C. fornicata, by measuring density, shell length, and mating stack characteristics of 19 populations distributed from northern Maine to Rhode Island. We found that slipper limpet density was higher at more southern sites and in protected locations. Additionally, we examined slipper limpet densities from photographs of fouling panels in New Hampshire in the 1980s and 2010s and found that there has been a 104-fold increase in population density at this site. In the second chapter, we used laboratory experiments to test the value of a known prey species (blue mussels) to that of a more readily available prey species (slipper limpets) to a suite of three native and two invasive crustacean predators. We tested the prey species and size preference of each predator, measured the nutritional condition of predators on a diet of each prey species, the handling time required to eat certain prey, and recorded instances of predation in the field. We found that there was some preference for blue mussels, and that most predators had better nutritional condition on a diet of blue mussels, indicating that slipper limpets are not an equivalent replacement for M. edulis as a prey source for crustacean populations. The third chapter focuses on population level differences in shell morphology of slipper limpets and how distinct shell shape influences limpet respiration and filter feeding. We measured the rate of filter feeding and the rate of oxygen consumption of limpets sourced from a population in Maine and one from Rhode Island. These physiological rates were measured after limpets were commonly held at acclimation conditions representative of summer habitat temperatures and a thermally stressful temperature. We found that wider, shorter, individuals had higher respiration and clearance rates than skinny, tall individuals, potentially linked to increased gill weight associated with the squat morphotype. Individuals from southern populations had higher clearance rates than northern individuals, but there was no impact of temperature. These results suggest that C. fornicata is able to maintain its physiological processes at temperatures that are well beyond those encountered within its natural environment. This speaks to their wide environmental tolerances and ability to succeed under climate change scenarios. Additionally, the high clearance rates of southern populations may have negative impacts on benthic communities. In their invasive range, C. fornicata significantly alters plankton communities, and deposits fecal matter on the benthos, encouraging bacterial growth and oxygen consumption. The loss of oxygen has resulted in the death of benthic organisms and a loss of biodiversity. As some C. fornicata populations in New England are equivalent to those in Europe, and are predicted to increase with warming seawater over the coming years, we will likely see some of these negative impacts within their native range.

Combined, these findings suggest that slipper limpets will succeed under climate change scenarios, likely because they possess many of the qualities similar to that of an invasive species. They are generalists in their feeding preferences, habitat choices, and physiological tolerances, enabling them to persist and thrive in many environments. Similar to an invasive species pushing out a native species, a replacement of the native species, Mytilus edulis, as a foundational benthic species in the Gulf of Maine likely will have detrimental impacts on native crustacean predators, as slipper limpets fail to meet the nutritional needs of native predators. Additionally, spatially separated populations of C. fornicata have different morphological traits that affect their physiological abilities and are able to function at higher temperatures than they regularly experience, further pointing to their ability to succeed in a changing climate. These studies underscore the importance of examining how native species are responding to climate change, and how changing conditions can transform a native species into a nuisance species

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