Resilience in the face of natural disturbances: conservation management and wildlife responses

Abstract

Major pressures on biodiversity are increasing globally, eroding within-species genetic diversity, leading to population declines and extinctions, and threatening the persistence of whole ecosystems. Climate change is exacerbating such pressures, in part due to increasing the intensity, frequency, and extent of natural disturbances. Investigations into the effectiveness of conservation actions are therefore urgently required to address threats to biodiversity following major disturbances. In this thesis, I explore animal responses to management interventions following a severe fire at a conservation reserve (North Head, Sydney) and investigate the genetic responses of a reintroduced small mammal population to the fire. Specifically, I tested two types of post-fire artificial refuge and found that small mammals and other ground-dwelling vertebrates readily used tunnel-like refuges that were deployed within days of the fire, but that animals rarely entered small modular refuges deployed one-year post-fire. These findings indicate that management interventions can provide refuge for small mammals following fire, that interventions are likely to be most critical within months following fire, and that field trials are imperative for assessments of efficacy. Using a long-term genetic monitoring dataset, I then detected no adverse genetic consequences of the fire within a reintroduced bush rat (Rattus fuscipes) population, despite the fire sensitivity of the species. This unexpected result can likely be attributed to the recovery of critical resources following a year of high La Niña rainfall, paired with targeted management efforts, including strategic genetic admixture of population founders and a series of post-fire interventions. Overall, this thesis reveals novel insights into the effective use of post-disaster management interventions and highlights the power of conservation actions in supporting species, and potentially ecosystem, persistence into the future.