Browsing by Author "Dunham, Amy"

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    Population Dynamics of Heritable Symbionts when Accounting for the Life History Complexity of their Host
    (2015-06-12) Bibian, Andrew James; Miller, Tom E.X.; Dunham, Amy; Rudolph, Volker
    I developed theory and experiments to understand how complex life cycles of a host affect the dynamics of their heritable symbionts, important ecological and evolutionary agents. With symbiont persistence and prevalence being a function of their effects on host fitness and transmission efficiencies, accounting for host demographic “storage,” in the form of non-reproductive or dormant host life stages, leads to unexpected results. Symbiont loss from demographic storage affects persistence similarly to loss from a host reproductive stage. Loss from host dormancy, however, affect dynamics if symbiont passage through the dormant stage occurs at a high rate, which we observed with experiments. Demographic rescue and symbiont persistence was possible, and observed, whereby stage specific symbiont benefits compensate for symbiont loss. Empirically, accounting for host dormancy in the form of a plant seed bank facilitated symbiont persistence and prevalence. Our results emphasize the importance of accounting for realistic complexity in host-symbiont dynamics.
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    Regional comparison reveals the negative impact of human activity on patterns of primate diversity
    (2023-02-27) Brandon, Kristin; Dunham, Amy
    Primates have irreplaceable roles in cultural, scientific, and ecological systems, yet nearly two-thirds of species are threatened with extinction. While the natural processes involved in primate community assembly are well known, we understand less about the role humans play in influencing associated patterns of diversity. Here, we examine the unresolved relationships between anthropogenic activities, spatial and environmental filters, and patterns of primate diversity by assessing species richness across the Afrotropical, Indomalayan, Malagasy, and Neotropical realms. We found regional differences in the predictors associated with primate diversity. Fragmentation and mammalian defaunation were the most important disturbance variables and either independently or synergistically contributed to observable patterns of lower species richness in all realms except Madagascar. In the midst of a current biodiversity crisis, understanding macroscale patterns of diversity and the role humans play in altering these are critical for preserving biodiversity and preventing further declines.