Sensitivity of some Australian animals to sodium fluoroacetate (1080): additional species and populations, and some ecological considerations

Abstract

The sensitivity to fluoroacetate (1080) of a number of species of rodents and dasyurids with and without evolutionary exposure to fluoroacetate-bearing vegetation was determined. Rattus fuscipes, and species of Pseudomys from populations with exposure to this vegetation, were particularly tolerant to fluoroacetate. However, the level of tolerance varied among the different populations of each species, depending on the degree to which the toxic plants were present in their microhabitat. The tolerance of the F1 offspring of sensitive R. fuscipes (South Australia) crossed with tolerant conspecifics from Western Australia was mid-range between those of the parental populations. The sensitivity of introduced R. rattus and Mus domesticus from areas with fluoroacetate-producing plants in Western Australia was similar to that reported elsewhere for these rodents. This suggests that their relatively short coexistence with the toxic plants has had little obvious impact on their level of sensitivity to fluoroacetate. The dibbler, Parantechinus apicalis, which coexists with the toxic vegetation, was exceptionally tolerant for a native carnivore/insectivore (LD50 ~35 mg 1080 kg–1). In contrast, however, Phascogale tapoatafa from southern Western Australia was more sensitive to 1080 than was expected, with an estimated LD50 of 7 mg 1080 kg–1. Although the level of tolerance to fluoroacetate was seen to vary depending on the level of exposure of each species/population to fluoroacetate-bearing vegetation, our findings provide further evidence of the evolutionary impact that fluoroacetate-producing plants appear to have had on the genetic composition of indigenous Australian fauna.

Biodiversity hotspots and Ocbil theory

“…6 (h) pronounced myrmechory x x Ant dispersed flora Mucina and Majer (2012) x x x Miconia (Melastomataceae) Lima et al (2013) x x glob Angiosperms with ant-dispersed seed Lengyel et al (2009Lengyel et al ( , 2010 x x NSW Myrmechory more common in infertile soils Berg (1975); Westoby et al (1991) 6(i) special defences from herbivory Gastrolobium (Fabaceae) poison peas Peacock et al (2011); Twigg and King (1991); Twigg et al (2003) 6(j) Bioengineering of soils and niche construction…”

Ecology of Australia: the effects of nutrient‐poor soils and intense fires

“…The emu ( Dromaius novaehollandiae ), which may play a role in the dissemination of myrmecochorous legumes, is extremely tolerant for an endothermic animal (Twigg et al , 1988; Twigg & King, 1991). Several genera of marsupials and rodents also have evolved tolerance to fluoroacetate (Twigg et al , 2003). Fluoroacetate acts quantitatively as a defence against fibre‐tolerant kangaroos and native Lepidoptera, which have relatively slow metabolism (Twigg, 1990; Twigg & King, 1991).…”

Response of feral cats to a track‐based baiting programme using Eradicat® baits

“…, , ) where the native fauna have a relatively high tolerance to 1080 poison because they have co‐evolved with endemic plants containing a similar compound (Twigg & King ; Twigg et al . ). Alternative means of bait presentation that reduce nontarget risk but maximise uptake by cats, such as suspending baits above the ground (Algar & Brazell ), should be investigated for use in other parts of Australia.…”

“…Cats are less likely than canids to locate and excavate buried baits because they are primarily auditory and visual hunters (Bradshaw 1992;Fisher et al 2014b) that lack the acute olfactory senses of canids. Surface laying of cat baits is standard practice is Western Australia (Algar et al , 2013 where the native fauna have a relatively high tolerance to 1080 poison because they have co-evolved with endemic plants containing a similar compound (Twigg & King 1991;Twigg et al 2003). Alternative means of bait presentation that reduce nontarget risk but maximise uptake by cats, such as suspending baits above the ground (Algar & Brazell 2008), should be investigated for use in other parts of Australia.…”