Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Fire and Rain : Investigating How Major Ecological Drivers Shape a Semi-Arid Bird Community over Space and Time.

Auteur : Connell, Jemima.

Université de soutenance : La Trobe University

Grade : Doctor of Philosophy (PhD) 2019

Résumé
Major environmental drivers like fire and climatic extremes operate over large temporal and spatial scales to shape species’ distributions through the variable provision of resources. Effective management of fire-prone ecosystems can be hampered by limited availability of fire history data at appropriate scales, and limited understanding of how such drivers may interact to alter species’ distributions. This affects the conservation management of rare and threatened taxa, many of which are paradoxically most susceptible to inappropriate fire regimes. Using a semi-arid bird assemblage of south-eastern Australia as a case study, this thesis had two major objectives. First, I predicted the effects of a century of fire on rare and threatened bird species across an expansive fire-prone region, and assessed how a contemporary fire management approach would drive changes to future habitat suitability. I found all species were strongly affiliated with time since fire, mid-successional age-classes ( 20-60 years post-fire) were highly important for most species, and several species were likely to be vulnerable as a result of limited or isolated habitat. I found a short-term fire planning approach could, over time, substantially alter the extent and distribution of post-fire age classes across large landscapes, with potentially detrimental outcomes for these species. Second, I tested the effect of climatic extremes on population fluctuations of the entire bird community, and how extremes influenced species’ associations to time since fire, during severe El Niño drought, subsequent La Niña rainfall and in a return to below-average rainfall. I found drought-breaking rainfall strongly influenced species’ occurrence rates, its effects were sustained for multiple years, and climatic extremes interacted with fire history to shape species’ distributions. My research highlights that fire management of at-risk species must allow for the adequate provision of particular seral stages over time and that species’ responses to fire history are spatially and temporally dynamic. An understanding of multiple factors affecting species persistence must be integrated to achieve effective fire management.

Présentation

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