Cane toads
We will Stop the Cane Toads getting into WA!
The Kimberley Toad Busters are the only truly totally volunteer group
on the ground (since the 10th Sept. 2005) trying to stop the cane toad
from getting across the Western Australian border. To date we have
largely met all field expenses from community fund raising efforts, local government input and community donations, the
ongoing support of Biodiversity Protection Inc (and recently a comittment of $79,000 from the Federal Government) .
Despite the State Government committment of half a million dollars towards the cane toad fight, this local volunteer
group has not received one dollar of this money. Eight months later this volunteer group is sustainable only because of
local community financial input and the belief that we have provided, for the first time in 70 years, an ability to 'hold' the
cane toad front line while government and scientists find a 'biological' solution to the relentless march of the cane toad.
Local extinction of northern quolls – the effect of cane toad invasionMeri Oakwood & Amber Hooke Envirotek, Ecological Research, Survey and Education PO Box 25 , Nana Glen NSW 2450 Email: envirotek@hot.net.au Ph: (02) 6656 9079 Email: amberlucija@hotmail.com Ph: (08) 8979 2199 Abstract Cane toads (Bufo marinus) were introduced to coastal Queensland in 1935 and they have been spreading south, north and north-west ever since. Cane toads possess toxic glands and consequently their consumption is fatal to many vertebrate predators. As cane toads colonized Cape York , Queensland between the mid 1980s to the mid 1990s, major crashes in populations of conspicuous native vertebrate predators were observed, in particular goannas and northern quolls (Burnett 1997). The northern quoll, Dasyurus hallucatus, a small marsupial carnivore, is a declining species now listed as “lower risk, near threatened” by the IUCN. The Northern Quoll was determined by the ERISS Risk Assessment of Cane Toads in Kakadu National Park (Kakadu) (Van Dam et al. 2000) to be the single highest risk species in Kakadu. In 2001, our project was established in Kakadu to monitor the short-term and long-term impacts of cane toads on individuals and populations of the northern quoll. Additionally, we monitored the abundance of toads during invasion and examined their prey. We examined two northern quoll populations:
Both sites had regular trapping sessions conducted from 2001 to 2004 to gather pre-invasion baseline population data and to monitor quoll population trends during and after cane toad invasion. Radio-tracking of northern quolls (n=40) was conducted at the Mary River site from January to June 2002. The toads arrived at this site in February 2002. After cane toad arrival, 31% of quoll deaths (total n=16 deaths) were due to cane toad poisoning. The signs of cane toad poisoning are distinctive in quolls: there are no injuries or predator damage on the corpse, and they have bright red lips and/or gums that are probably due to irritation from the cane toad toxins (photo in Oakwood 2004). Additionally, corpses often have a variety of other signs including bleeding from the nose and ears, bright purple teats and some abnormalities in the colour of internal organs. The Mary River population became extinct in February 2003. Eight subsequent trapping sessions in 2003 and 2004 failed to detect any quolls at this site. Radio-tracking (n=41) occurred at the East Alligator site from March 2003 to January 2005. Cane toads arrived in November 2003. After cane toad arrival, 53% of quoll deaths (total n=15) were due to cane toad poisoning. This population has dramatically declined from 45 individuals in January 2003 to 4 in January 2005. Radio-tracking and trapping ceased in January 2005 due to lack of funding, disallowing the completion of the study. Consequently, we will be unable to determine the timing of extinction of this population, unless we can obtain funding for monthly trapping for March and April. The project to date has investigated the short-term effect of cane toads on northern quolls but at this stage, it looks as though we will be unable to complete the second main objective, to document the long-term impact. We are still hopeful that sufficient funding will be sourced to enable us to complete the project; to carry out annual post-extinction trapping to determine whether any re-colonisation occurs over the next few years. This project has provided data that has been used for the recent nominations for the northern quoll to be listed as a Threatened species and for the cane toad to be listed as a Key Threatening Process under the federal Environment Protection and Biodiversity Conservation Act1999, as part of the basis for justification for the quoll translocation project to the English Company Islands by the NT DIPE in 2003 and for the establishment of a quoll captive breeding program near Darwin in 2004. Further Reading Burnett, S. (1997) Colonising cane toads cause population declines in native predators: reliable anecdotal information and management implications. Pacific Conservation Biology3: 65-72. Oakwood M. (2004) Case of the Disappearing Spots. Nature Australia28: 26-35. van Dam R., Walden D. & Begg G. (2000). A preliminary risk assessment of cane toads in Kakadu National Park . Unpub. Report by ERISS, Jabiru. |
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