Patterns and mechanisms of intraspecific trait variation across thermal gradients in a marine gastropod

• Main Author: Villeneuve, Andrew R
• Format: Others
• Published: ScholarWorks@UMass Amherst 2021
• Subjects: Local adaptation; thermal tolerance; countergradient variation; thermal performance curve; environmental drivers; climate change; Comparative and Evolutionary Physiology; Marine Biology; Other Ecology and Evolutionary Biology
• Online Access: https://scholarworks.umass.edu/masters_theses_2/1027; https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=2068&context=masters_theses_2

As the earth’s climate changes due to anthropogenic emissions, it has increasingly become an imperative within the ecological community to understand existing species adaptations to climate change. Much focus has been paid to how a species might react to climate change, but the role of locally adapted traits and responsible environmental mechanisms have received less attention. Quantifying how sublethal (e.g. growth rates) and lethal (e.g. thermal tolerance) trait performance vary between populations can thus improve our understanding of how populations, and the entire species, will react to climate change. Here, I quantified the spatial patterns of performance of several traits in populations of the predatory marine snail Urosalpinx cinerea from across two thermal gradients on the Pacific and Atlantic coasts of North America. In chapter 2, I quantified local adaptation and plasticity of thermal tolerance, warming tolerance, and developmental traits of Urosalpinx. I found that while low latitude populations have evolved higher thermal tolerance than their low latitude counterparts, they also demonstrate negative plasticity in response to higher acclimation temperatures. This is likely a result of low latitude population adaptation to cooler developmental conditions. Further, low latitude populations live in environments much closer to their thermal maxima than high latitude counterparts, resulting in higher climate sensitivity in low latitudes. In chapter 3, I quantified growth and consumption rates of Urosalpinx via a common garden experiment. I found evidence for a novel pattern of trait adaptation, wherein high latitude populations tended to have higher trait performance at higher thermal optima than low latitude counterparts. This can be attributed to the maximizing of growth rate during short growing seasons at high latitudes. Together, these results demonstrate that local adaptation in endemic across two traits in Urosalpinx. I demonstrate that these traits tend to be adapted to aspects of the environment directly related to aspects of Urosalpinx phenology, and not to environmental means as is commonly assumed. These insights suggest that models of organismal performance under climate change must consider not only the potential for local adaptation in populations, but also the aspects of the environment to which these populations are evolved.