Mike Stevens
Introduction
Small mammal trapping in the Grampians National Park has been conducted through Parks Victoria’s Fox Adaptive Experimental Management (Fox AEM) project since spring 2003. The Fox AEM program ceased in 2007 with a comprehensive review of Grampians data provided by Robley et al. (2008). The Victorian Governments is funding $1.3 million over four years (2008 to 2012) for the Grampians National Park to extend the Grampians Fox AEM as “Grampians Ark” joining the flagship state-wide fox baiting initiatives. The Grampians Ark is committed to continue prey response monitoring in attempts to quantify the benefit to biodiversity of landscape-scale fox poison baiting.
Spring 2003, 2004, 2005 displayed promising prey response results (Robley and Wright 2006).
However, in January 2006 a severe landscape-scale wildfire burnt almost half of the Grampians National Park including five of the seven long term study sites established as part of the Fox AEM program. Mammal trapping continued in spring 2006 and 2007 at the seven long term study sites with zero small mammals captured during both monitoring periods at burnt sites. Robley et al. (2008) conducted a review of all Parks Victoria Fox AEM program areas between 2003 and 2007 concluding that low capture rates in the Grampians (and other areas) led to unreliable estimates of animal abundance. The results of this review combined with the lack of success in 2006 and 2007 led to the decision to alter the Grampians mammal trapping program into two components. The first being a spring program investigating the response of small mammals to fox baiting and secondly, an autumn program in conjunction with Deakin University investigating impacts to fauna and habitat of the 2006 wildfire.
Following the autumn and spring 2008 surveys, concern was raised over the lack of
conservation significant species detected, particularly Long Nosed Potoroo and Southern Brown Bandicoot . As a result, a pilot program was instigated in partnership with Deakin University to investigate the use of remote infrared digital cameras for detecting target species. This culminated in the establishment of an honours research project (DeBondi 2009).
Methods
All traps during 2008 and 2009 were baited with a mixture of quick cook rolled oats, smooth peanut butter, honey, vanilla extract and raw linseed oil with baits replaced in all traps mid way through each trapping session to maintain bait attraction.
2008 spring trapping
Small mammal trapping was conducted in fox poison baited and unbaited areas of the Grampians National Park . All sites were located in areas of the Grampians that were unburnt by the 2006 wildfire. Sites were trapped for one session consisting of six consecutive nights with captured animals identified to species, weighed, sexed and fur-clipped on the hind quarters for recapture identification.
2009 spring trapping
The 2009 program targeted fox poison baited monitoring sites in parts of the Grampians
National Park that were unburnt by the 2006 wildfire. The program was implemented
similar to the 2003 to 2005 program with trapping conducted over two trap sessions consisting of six nights each with a two week break between sessions.
The 2009 program differed to the 2008 program however by having an additional nine wire cage
traps (25 cage traps in total) installed at every second Elliot trap per site to increase the potential to capture critical weight range mammals, specifically Long Nosed Potoroo and Southern Brown Bandicoot.
Results
Spring 2008
The spring 2008 program conducted 4290 trap nights (1056 cage and 3234 Elliot trap nights). There were 176 capture events of 126 individual animals across 16 species
Spring 2009
The spring 2009 prey response trapping conducted 4248 trap nights with 552 captures of 230 individual animals across 12 species.
Of importance is the absence of critical weight range fox prey species Long Nosed Potoroo and Southern Brown Bandicoot with only an individual Bandicoot captured between 2008 and 2009 . The use of remote digital cameras in Stevens et al. (2010) however, led to six Southern Brown Bandicoot and three Long Nosed Potoroo ‘camera captures’ in 926 camera trapping nights in summer 2009. The achievements with remote digital cameras has resulted in far superior detection of critical weight range mammals with only 35% of the monitoring night effort required and significant labour savings to a live trapping program. These results suggest that the camera trapping technique presents opportunities to target these conservation significant species in the Grampians.
Conclusion
The considerable effort to obtain this large and consistent data-set in the Grampians National Park has only been made possible with the support of Conservation Volunteers Australia, their dedicated participants and Parks Victoria staff. Although the data has provided limitations, some positive signs exist of native small mammal response to fox baiting efforts. The last seven years of research effort has been essential to enable true, landscape-scale adaptive management allowing for the opportunity to now review the entire monitoring program and evolve the research and
monitoring component of Grampians Ark for the next seven years.
Note: This is just a summary of Mike’s 14 page report. Contact him if you would like the full report.