Date of Award

Summer 8-15-2024

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Ecology and Environmental Sciences

Advisor

Alessio Mortelliti

Second Committee Member

Sydne Record

Third Committee Member

Danielle Levesque

Abstract

Personality, or the tendency for individuals to behave consistently, has been observed throughout the animal kingdom and is known to have key ecological and evolutionary consequences. Because different personalities play distinct roles in a community, it is critical to understand which personalities are more likely to complete vital ecosystem functions, and how anthropogenic land-use change may influence personality compositions of a population. The purpose of my research is to contribute to filling these knowledge gaps, using forest-dwelling small mammals as a model system. Small mammals such as mice and voles play a fundamental role in the ecosystem service of seed dispersal by caching seeds in small hoards that germinate under beneficial conditions, facilitating forest regeneration. Personality has been found to influence decision-making during foraging, resulting in different seed dispersal outcomes. Within the context of an 8-year capture-mark-recapture study, we trapped and tested the personality of small mammals using standardized behavioral tests in the Penobscot Experimental Forest in Maine.

Chapter 1 focuses on pilferage, a key step in the seed dispersal process in which animals steal seeds from other individuals’ caches. Pilferers often recache stolen seeds, which are often pilfered by new individuals, who may recache again, and so on, potentially leading to compounded increased dispersal distance. Within the context of the long-term study, we conducted a pilferage experiment, in which we created artificial caches using eastern white pine (Pinus strobus) seeds monitored with trail cameras and buried antennas for individual identification. Of the 436 caches created, 83.5% were pilfered by 10 species, including deer mice (Peromyscus maniculatus) and southern red-backed voles (Myodes gapperi). We show how individuals differ in their ability to pilfer seeds and that these differences are driven by personality, body condition, and sex. More exploratory deer mice and those with lower body condition were more likely to locate a cache, and female southern red-backed voles were more likely than males to locate caches.

Chapter 2 investigates the effects of land-use type on personality compositions and its potential implications on activity patterns. Managed forests make up over half of forests globally, with the majority used for timber harvest. To ensure efficient forest regeneration, it is vital that we understand how different management regimes affect the behaviors of seed-dispersing and seed-predating animals. We used personality data from 325 individual American red squirrels (Tamiasciurus hudsonicus) over 8 years across different silvicultural treatments. During 2 years of the study, we deployed collar-mounted light-level geolocators on 14 individual squirrels to measure daily activity patterns. Our analysis reveals that personality distributions differ between unmanaged and managed forests, and that personality influences activity patterns. Specifically, uniform and irregular shelterwood forests had lower proportions of aggressive individuals than unmanaged forests, and more exploratory individuals spent more time active per day on average. My research adds to a growing body of knowledge showing that the unique personalities of individual small mammals play a critical role in forest regeneration by impacting seed dispersal, and that anthropogenic alterations to landscapes can shift personality compositions, with ecological implications.

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