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Diet of the invasive red fox (Vulpes vulpes) in the Pilbara, Western Australia
Thesis   Open access

Diet of the invasive red fox (Vulpes vulpes) in the Pilbara, Western Australia

Natalie Grassi
Masters by Research, Murdoch University
2022
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Abstract

Red fox--Nutrition--Western Australia--Pilbara Animals--Effect of exotic animals on--Western Australia--Pilbara Introduced animals--Nutrition--Western Australia--Pilbara
Context: The invasive red fox (Vulpes vulpes) plays a key role in predation suppression of many native Australian species. Diet analyses are an important conservation tool for elucidating trophic interactions, although many analyses provide only a generalised overview of fox diet, and rarely consider the effects of methodology or age-cohort in creating variation in diet composition. Aim: This study provides the first quantification of Pilbara fox diet (1) to determine diet variation between methodologies (2) compare diet between age-cohorts, and (3) compare Pilbara fox diet to existing Australian diet analyses. Methods: Feeding ecology was studied through morphological analysis of 144 scats and 23 stomachs collected between 2016-2019 from two sites along the north-west shelf turtle nesting rounds; Mundabullangana Station and Onslow. Key results: Vegetation, invertebrates and native mammals were the most dominant components of regional diet. There was significant variation between methodologies, with macropods (p<0.001), cattle (p=0.003) and dragons (p=0.006) contributing most significantly to dissimilarity, due to the varying survivability of remains during digestion. Diet composition did not vary significantly between age-cohorts, although flatback turtle (Natator depressus) occurrence was positively associated with adult diet (p=0.043). Pilbara fox diet varied significantly to fox diet across Australia, with a significantly greater incidence of macropod (p<0.001) and reptile (p<0.001) for both sample types. Conclusions: Impacts were identified on native and threatened species, with native wildlife comprising a greater proportion of fox diet than introduced species in this region compared with other parts of the country, providing additional evidence of fox suppression against native wildlife. We also identified variation in diet composition by methodology, suggesting the need for multiple sample types to be included in diet analyses to provide more accurate representation of predator diets. Following revision of biologically irrelevant data in preliminary results, genetic analyses will be used to further support morphological results.

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