Resource pulses affect prey selection and reduce dietary diversity of dingoes in arid Australia

Abstract

In Australia, the dingo Canis lupus dingo is the largest terrestrial predator. Dingoes contribute to ecological processes and functions throughout their continental geographic range. Their generalist diet enables daily energetic requirements to be met even in the resource‐limited deserts of central Australia, where irregular rainfall drives extreme fluctuations in mammal assemblages. Given that predation is a primary driver of declining mammal populations and failed reintroductions, it is necessary to understand the dietary intake of the continent's apex predator if conservation outcomes are to be achieved. We performed a meta‐analysis of the mammalian composition of the dingo's diet throughout Australia's arid zone, an area covering c. 5.4 million km2. We used 25 data sets from 11 studies to measure the effects of resource booms and anthropogenic disturbance (pastoralism) on diet. We explored whether the probability of prey species occurring in the diet was related to the size of the prey or to prevailing conditions. We also investigated the similarities in diet between dingo populations from across the arid zone, and how dietary overlap was affected by opposing land uses. Dingoes primarily consumed medium‐sized (35–5500 g) and large (>5500 g) mammals, whereas most small mammals (<35 g) were consumed infrequently, or not at all. The composition of the diet changed dramatically during resource booms to exploit irruptive prey species such as long‐haired rats Rattus villosissimus (native; 144 g) and house mice Mus musculus (introduced; 20 g). During resource booms, the consumption of large mammals decreased significantly, whereas the occurrence in the diet of medium‐sized mammals remained high. The diversity of species consumed by dingoes was significantly lower during boom periods than during non‐boom periods. The dingo's heightened consumption of hyper‐abundant species has the potential to release many non‐target species from direct predation pressure during boom times. This could be advantageous for remnant and reintroduced populations of mammals, which are especially susceptible to predation.

Accelerometer informed time-energy budgets reveal the importance of temperature to the activity of a wild, arid zone canid

“…Dingoes repeatedly shelter in discrete areas for resting, rearing offspring, and/or socialising (hereafter referred to as ‘shelters’) and thus they may be an important predictor of energy use [ 42 ]. We used the R package ‘recurse’ [ 43 ] to identify shelters for each dingo by using a combination of 1) revisiting the same location (25 m radius), and 2) the average amount of time spent at that location (residence time).…”

“…It is located in the The dingoes at Kalamurina possess high levels of dingo ancestry [26], making this study the first assessment of energetics in a wild population of pure dingoes. European rabbits Oryctolagus cuniculus, c. 1.6 kg comprise the bulk of their diet, but they also consume reptiles, birds, invertebrates, and vegetation [27].…”

Phenotypic variation and promiscuity in a wild population of pure dingoes (Canis dingo)

“…Body weight of adult dingoes can be highly variable depending on geographic location and available resources (see Allen & Leung, 2014), and we reported some of the heaviest weights for a dingo population (Table 1). The primary prey item of dingoes in this study was European rabbits (c. 1.6 kg; Tatler, Prowse, Roshier, Allen, & Cassey, 2019b), which indicates that it is not the size of the prey items that dictate the body size of dingoes. Akin to wolves, intact populations of dingoes are likely to be intrinsically regulated and therefore we might expect a male sex bias (Phung, Wayne, Wilson, & Lohmueller, 2018; Wolff, 1997).…”

Accelerometer informed time-energy budgets reveal the importance of temperature to the activity of a wild, arid zone canid

“…Activity patterns of predators usually coincide with those of their major food source, which are also linked to ambient temperature (e.g., Jenny, 2005, Harmsen et al, 2011. Rabbits comprise the bulk of dingo diet in the arid zone (Tatler et al, 2019a) and they are most active in the early evening and throughout the night. Moreover, as a vagile species, constraining high activity movements (or reducing them altogether) to the less climatically extreme times of the day is likely an adaptation to mitigate thermal stressors associated with desert life (Nathan et al, 2008, Aublet et al, 2009, Norris and Kunz, 2012.…”

“…9˚C -19. The dingoes at Kalamurina possess high levels of dingo ancestry (Tatler et al 2020), making this study the first assessment of energetics in a wild population of pure dingoes. European rabbits Oryctolagus cuniculus, c. 1.6 kg comprise the bulk of their diet, but they also consume reptiles, birds, invertebrates and vegetation (Tatler et al, 2019a).…”