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Accueil du site → Master → Australie → Potential for resource competition between the boodie (Bettongia lesueur) and mala (Lagorchestes hirsutus) in the fenced Matuwa reserve, central Western Australia

Edith Cowan University (2022)

Potential for resource competition between the boodie (Bettongia lesueur) and mala (Lagorchestes hirsutus) in the fenced Matuwa reserve, central Western Australia

Treloar Shannon

Titre : Potential for resource competition between the boodie (Bettongia lesueur) and mala (Lagorchestes hirsutus) in the fenced Matuwa reserve, central Western Australia

Auteur : Treloar Shannon

Université de soutenance : Edith Cowan University

Grade : Master of Science (Biological Sciences) 2022

Résumé
Translocations to closed systems such as fenced reserves are commonly used for the conservation of threatened fauna species worldwide and although fenced reserves can provide significant conservation benefits to biodiversity, they can also bring forth potential threats. Ecologically similar species can stably coexist by partitioning resources along at least one of three niche dimensions (food, space, or time), thereby reducing interspecific competition. However, resources are limited in fenced reserves and natural processes that regulate populations in response to resource availability, such as dispersal into surrounding areas, are unable to occur. Consequently, there is increased potential for competition because there are less resources available for partitioning. Furthermore, the removal of predators and competitors, both native and introduced, can increase the risk of overpopulation due to a reduction in the incidence of density-dependant mortality. This can potentially lead to overuse of resources and further increase the potential for competition. Interspecific competition may lead to the decline or exclusion of a more sensitive species by a less sensitive species. Such interactions are difficult to predict, especially as many threatened species no longer naturally co-exist in their current ranges or are poorly studied.

I investigated resource use of two potentially competing native marsupials, boodies (Bettongia lesueur) and mala (Lagorchestes hirsutus), that co-exist in a 1100 ha predator-free fenced reserve located in the arid rangelands of central Western Australia. Resource overlap between coexisting populations of these two species has not been studied previously, but the literature suggests the potential for considerable dietary overlap. I investigated the degree of dietary overlap using scat DNA from non-invasively collected scats, as well as the degree of spatial overlap using scat counts and temporal overlap using camera traps. Boom-bust dynamics have been observed in the Matuwa boodie population (and elsewhere), which raised the concern of subsequent suppression of the potentially less competitive mala. The suppression of mala however cannot be confirmed because there are currently no effective methods to monitor the population size of this elusive species at Matuwa. Therefore, I also trialled non-invasive DNA-based sampling methods using field-collected scats to estimate the abundance of the Matuwa mala population. This method has not been used on mala previously.

Présentation

Page publiée le 6 avril 2022