ON THE ECOLOGY OF INVASIVE SPECIES, EXTINCTION, ECOLOGICAL HISTORY, AND BIODIVERSITY CONSERVATION
Donlan, Charles Joseph
For thousand of years, invasive species have changed ecosystems and caused extinctions. Nowhere is this more apparent than on islands. Those ecosystem changes and extinctions are result of strong species interactions between invasive species and native communities. However, extinctions are rarely random and are often influenced by a suite of biotic and abiotic factors. Understanding the intricacies of invasions and their consequences is central to ecology and conservation. Here, I explore three aspects of invasion biology: 1) the ability to remove invasive mammals from islands and the biodiversity benefits, 2) the ability to predict extinctions caused by invasive species, and 3) the role ecological history plays in dictating nativeness with respect to restoration. Chapter one provides a brief overview of the three-decade progress of invasive mammal eradication on islands. I review the history of eradication techniques developed in New Zealand, and describe some recent successes in western Mexico and Gal?pagos that I have been part of over the past decade. Chapter two provides one example of the biodiversity benefits of eradication: the recovery of the Gal?pagos rail that was heavily impacted by invasive goat and pig populations prior to their removal from Santiago Island. Chapter three and four test advocated and explore new conservation tools for their ability to predict extinction-prone species. At the core of these two chapters is an attempt to evaluate whether biogeography tools are useful in predicting species endangerment, or whether knowing the autecological details of a species and their community interactions is necessary to correctly gauge extinction risk. Chapter five tackles the role ecological history in gauging ?nativeness?. I provide a framework that justifies the restoration of missing ecological functions and evolutionary potential of extinct species using extant conspecifics and related taxa. Pleistocene Rewilding is conceived as managed ecosystem manipulations whereby costs and benefits are addressed on a case-by-case basis. It would broaden the underlying premise of conservation from managing extinction to encompass restoring ecological and evolutionary processes. Risks of Pleistocene Rewilding include the possibility of disease transmission, and unexpected ecological and sociopolitical consequences of reintroductions. Social challenges will include incorporation of pre-Columbian ecological frameworks into conservation strategies.
invasive species; extinction; restoration; conservation; Pleistocene rewilding
dissertation or thesis