The utility of coded very high frequency telemetry for monitoring reintroduced mammal populations.

Very high frequency (VHF) radio tracking technology deployed on terrestrial vertebrates has been well utilized in ecology without much evolution since the 1960s. With the advent of multi-species rewilding projects, and the new field of reintroduction biology, there has been an increase in requirements for telemetry systems to monitor survival and mortality for many animals simultaneously. Common, pulsed VHF can only monitor one individual on each radio frequency, and the number of individuals monitored is constrained by the amount of time spent on each frequency to facilitate a detection and the number of receivers. Coded VHF largely removes these constraints by using a digital code that can simultaneously monitor up to 512 individuals on a single frequency. Incorporated into an autonomous monitoring system, the coded VHF system also greatly reduces time in the field to confirm the status of individuals. Here we demonstrate the utility of coded VHF technologies applied to monitoring a reintroduced population of brush-tailed bettong (Bettongia penicillata) on the Southern Yorke Peninsula in southern Australia. A system of autonomous monitoring towers was able to monitor 28 different individuals simultaneously without having to change frequency on any of the towers. During a single 24-h period, one individual was recorded 24,078 times. Key benefits of the high detection rate and autonomous recording are, a timely response to mortalities or a predation event, the detection of nocturnal, cryptic, or burrowing species whenever they are active, and the reduced need for personnel to be in the field.

Physiological response after translocation differs between source populations in a threatened mammal.

Conservation translocations are an important tool in the prevention of species loss, but the translocation process is associated with numerous stressors. Non-invasively monitoring stress physiology via faecal glucocorticoid metabolites (FGMs) can provide valuable insights into factors impacting translocation success and how to mitigate negative impacts. After validating an assay to measure FGMs in greater stick-nest rats (Leporillus conditor), we examined whether translocation caused a predictable change in physiology. We compared longer-term (one to five months post-translocation) physiological responses across three source populations (remnant-wild, reintroduced-wild, captive-bred), and investigated effects of body condition and sex on FGMs. Notably, FGMs of the remnant-wild population did not significantly change post-translocation, while the reintroduced-wild population exhibited a significant decrease and the captive-bred population a significant increase. Individuals in lower body condition had the highest FGMs in both wild-type populations, whereas the captive-bred population showed the opposite relationship. There was no difference in FGMs between the sexes. Our work highlights that physiological responses after translocation may not be uniform and source population history is an important factor to be considered, emphasizing the need for novel ideas that facilitate successful adaptation. By better understanding how species and individuals respond to translocation, we can improve translocation outcomes.

In vitro invasiveness and antimicrobial resistance of Salmonella enterica subspecies isolated from wild and captive reptiles.

Reptiles are carriers of Salmonella and can intermittently shed bacteria in their faeces. Contact with snakes and lizards is a source of human salmonellosis. Here, two populations of reptiles, wild and captive were surveyed for Salmonella. One hundred thirty wild-caught reptiles were sampled for Salmonella including 2 turtle, 9 snake and 31 lizard species. Fifty-two of 130 (40%) animals were Salmonella positive: one of 5 (20%) turtles, 7 of 14 (50%) snakes and 44 of 111 (39.6%) lizards. One hundred twenty-two reptiles were sampled from a zoo collection including 1 turtle, 6 tortoise, 9 lizard, 14 snake and 1 crocodile species. Forty-two of 122 (34.4%) captive reptiles sampled were Salmonella positive. Salmonella was most commonly isolated from lizards and snakes. Fifteen serotypes were identified from zoo and 19 from wild-caught reptiles and most were members of subspecies enterica (I), salamae (II), arizonae (IIIa) or diarizonae (IIIb). Antimicrobial susceptibility testing was conducted on all Salmonella isolates; only two exhibited resistance, a Salmonella subsp. (II) ser. 21:z10 :z6 (Wandsbek) isolate cultured from a wild-caught reptile and a Salmonella Typhimurium DT120 isolated from a captive snake. The invasive capacity of reptile-associated Salmonella strains into cultured human intestinal epithelial (Caco2) and mouse macrophages cell lines (J774A.1) was also investigated. All isolates were invasive into both cell lines. Significant (P ≤ 0.001) variability in invasiveness into polarized Caco2 cells was observed. Salmonella Eastbourne exhibited the highest invasiveness into Caco2 cells and Salmonella Chester the lowest, with mean per cent recoveries of 19.99 ± 0.32 and 1.23 ± 0.30, respectively. Invasion into J774A.1 macrophages was also variable but was not significant. Salmonella subsp. II ser. 17:g,t:- (Bleadon) exhibited the highest invasiveness into J774A.1 with a mean per cent recovery of 10.19 ± 0.19. Thus, reptile-associated Salmonellae are likely to have different capacities to cause disease in humans.