Nathan Ranc Thesis Defense (Moorcroft Lab)


Monday, April 27, 2020, 1:30pm


Private for Committee Members only

Title: The interplay between memory and resource preferences drives animal space-use patterns

Committee: Paul Moorcroft and Francesca Cagnacci (Fondazione Edmund Mach, Italy) (Advisors), Bence Ölveczky, Naomi Pierce, John Wes Cain (Harvard Department of Mathematics)

Abstract: Many animals restrict their movements to a characteristic home range – a space-use pattern that is thought to result from the benefits of memorizing the locations and quality of heterogeneously distributed resources. Our understanding of how memory influences movements, and resulting space-use patterns, in nature is still in its infancy.

In Chapter 1, I analyse the spatial responses of a resident large herbivore (roe deer Capreolus capreolus) to an in situ resource manipulation experiment. I show that roe deer actively tracked spatio-temporal resource patterns leading to shifts in their movements and space-use. I further demonstrate that these behavioural adjustments are mediated by both individual resource preferences, and site familiarity.

In Chapter 2, I develop a spatial transition model to uncover the cognitive processes underlying roe deer foraging decisions during a field resource manipulation experiment designed to disentangle the effects of memory and perception. I demonstrate that roe deer rely on memory, not perception, to track the spatio-temporal dynamics of resources within their home range – a behaviour that can accurately be predicted by the proposed model.

In Chapter 3, I formulate a mechanistic movement model to quantify the role of memory in the movements of roe deer reintroduced into a novel environment. I show that an interplay between memory and resource preferences was the primary process influencing roe deer movements; and that it led to the formation of characteristic home ranges, as observed in the released individuals. 

In Chapter 4, I propose a mathematical model for home range formation that incorporates the influences of memory and resource preferences. By combining mechanistic modelling with field experiments, this Dissertation uncovers the role of memory in animal movements, and home range formation in nature.