Blackburn, Heather B., authorDetling, James K., advisorHobbs, N. Thompson, advisor2024-03-132024-03-132009https://hdl.handle.net/10217/237587Fragmentation of landscapes is a pervasive source of environmental change. Although understanding the effects of fragmentation has occupied ecologists for decades, there remain important gaps in our understanding of the way that fragmentation influences populations of mobile organisms. In particular, there is little tested theory explaining the way that fragmentation shapes interactions between consumers and resources. I propose a simple model that explains why fragmentation may harm consumers even when the total amount of resources on the landscape remains unchanged. In the model, I show that nonlinearity in the relationship between resource availability and benefit acquired from resources can cause a decrease in benefits to consumers when landscapes are subdivided into isolated parts. This decrease is the result of simple mathematical properties of the form of the relationship between resource availability and benefit, and is more severe with greater nonlinearity, with increasing fragmentation, or with greater unevenness of resource availability between fragments. I tested the predictions of the model using a laboratory system of cabbage looper (Trichoplusia ni) larvae on artificial landscapes. Consistent with the model's predictions, survivorship of larvae decreased with a combination of fragmentation and heterogeneity in resource availability. However, average mass of surviving larvae did not change in response to fragmentation alone. With basic knowledge of consumer resource use patterns and landscape structure, these observations can aid in making both generalized and quantitative predictions about the resource-mediated effects of fragmentation on consumers.born digitaldoctoral dissertationsengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.consumer-resource interactionshabitat fragmentationlandscape ecologyspatial heterogeneityecologyagricultureTextPer the terms of a contractual agreement, all use of this item is limited to the non-commercial use of Colorado State University and its authorized users.