Unintentional Victims of the Predator Proof Fence

Mulligans Flat and the Turtle Patrol

The Mulligans Flat Nature Reserve (Fig. 1), integrated into the greater Mulligans Flat – Goorooyarroo area can be found on the northern outskirts of Canberra. This area represents a critically endangered ecosystem of grassy box-gum woodland that was seriously degraded after 150 years of grazing practices. The Mulligans Flat Nature Reserve covers an area of 765ha with around 60% enclosed by a predator-proof fence (Shorthouse, et al., 2012).

mfr_map

Fig. 1: Mulligans Flat Nature Reserve, located near Canberra’s northern most suburbs

It is clear that many significant benefits have been achieved from the installation of the fence, but does present some drawbacks. I am referring to the native residents that are restricted by this boundary line, potentially putting some vulnerable creatures at risk. The known impacts mostly including disrupting movements of reptiles and mammals of which, the eastern long-necked turtle (Chelodina longicollis) is of main concern. Impacts upon the turtles include disruptions to migratory patterns as well as increased mortality rates from exposure, entanglement and predation (Ferronato, et al,. 2014).

One of the many Eastern Long-necked Turtles found on my patrol - Photograph: Gareth Quirke

One of the many Eastern Long-necked Turtles found on my patrol – Photograph:  Gareth Quirke

The issue that arises from a park managers perspective is that the fence itself is quite costly to maintain, hence continuously managing these turtle populations becomes quite time consuming. It is for this reason that Mulligans Flat relies heavily upon the enthusiastic involvement of community volunteers to help and protect the local turtle populations.

Eastern Long-necked turtle trapped on predator proof fence. Photograph: Gareth Quirke

Eastern Long-necked turtle trapped on predator proof fence – Photograph: Gareth Quirke

Recent studies in the area have shown the scale of this issue for the reserve. More than half of all reptiles caught on the fence tend to be the eastern long-necked turtle.What was worse is that an astonishing 9 out of 10 turtle deaths in and around the park were fence related (Ferronato, et al,. 2014).The most common causes for statistics was due to over-heating, followed by fox predation, vehicular collisions and entanglement. Being able to help prevent these turtle deaths is the reason that I, and so many other volunteers chose to join the Mulligans Flat Turtle Patrol.

 

The Work Itself  (13/9 – 12/10)

This volunteer work included a combination of turtle relocations and data logging. The majority of the time consisted of numerous walks up and down the southern perimeter of Mulligans Flat.The track itself can be seen in Fig. 2 which corresponds to the sightings that were recorded along the way (Fig. 3).

mfr_south

Fig. 2: The Southern Track of Mulligans Flat Nature Reserve

During the patrol, if a turtle was encountered, the first stage was to document its location through GPS coordinates to the Canberra Nature Map project. The details of individual turtle locations are used to help rangers and managers at Mulligans Flat to not only understand dynamics and populations of turtle movements, but also find hotspots to be targeted in future years. After photographed and tagged, each individual was carefully relocated 10m beyond the other side of the fence. Transportation of each turtle was carried out by placing it into a hessian bag and then carrying it by hand or in a bucket to the opposing side of the fence. This sometimes entailed large walking distances as entry gates could be anywhere up to 400m away.

Another Trapped Turtle. Photograph: Gareth Quirke

Another Trapped Turtle – Photograph: Gareth Quirke

This form of volunteer work is very popular and due to the large numbers of volunteers conducting this work, it was crucial to not move any turtle twice by accident. To ensure that a turtle wasn’t placed on the side that it was originally found, only turtles located directly on the fence were moved. Turtles away from the fence may have already been moved by previous patrols and therefore were not disturbed. While there were so many successful relocations, the nature of this work meant that unfortunately some fatalities did occur. It was the responsibility of volunteers to record each of these deaths, including its location. Each dead turtle was marked with a fluorescent paint to ensure that it was not recorded multiple times. Sightings of both dead and living turtles aims to assist managers at Mulligans Flat to identify trends of movements as well as associated potential causes of death.

As this was such a successful year for turtle rescues analysis of last years volunteer data was conducted as a comparison. It suggested that the southern section of the fence had the highest abundance of turtles relocated in 2015. So far, during the 2016-2017 period, 84 successful relocations have been made with many more still being logged every day. However, for reasons unknown, this year produced a far greater number of turtle relocations on the northern side. This knowledge has allowed for detailed ‘high traffic’ points to be located and shows how trends change between years.

The product of all this work was many successfully saved turtles and a map of wildlife sightings. As can be seen in Fig. 3, the southern fence track is shown with a variety of different symbols each representing a sighting. Alongside the turtle sightings many other animals were witnessed, each adding to the Canberra Nature Maps database. These included Shingleback lizards (Tiliqua rugosa), Bearded Dragons (Pogona barbata), Short-beaked Echidnas (Tachyglossus aculeatus) and even a Yellow Admiral Butterfly (Vanessa itea). All of my current and future sightings can all be found on my Canberra Nature Map profile as listed below.

Map of my recorded sightings recorded for the duration of volunteer work

Fig.3: Map of my recorded sightings recorded for the duration of volunteer work

The volunteering work at Mulligans Flat has a strong community base network aimed towards public involvement in the monitoring and development of the sanctuary. Without the enthusiastic support of the public for projects such as the Turtle Patrol, many aspect of the reserve would simply not be able to work as efficiently. This work has been an eye-opener, showing how easily rewarding it is knowing that a few turtle fatalities have been prevented due to the turtle watch. I will certainly be continuing on with my support at the reserve and strongly recommend others to be a part of this great experience.

Gareth Quirke – u5563390
Canberra Nature Map Profile: http://canberranaturemap.org/Community/Author/18241

Bibliography

Ferronato, B. O., Roe, J. H., & Georges, A. (2014). Reptile bycatch in a pest-exclusion fence established for wildlife reintroductions. In Nature Conservation vol.22 (pp. 577-585).

Shorthouse, D. J., Iglesias, D., Jeffress, S., Lane, S., Mills, P., Woodbridge, G., et al. (2012). The ‘making of’ the Mulligans Flat – Goorooyarroo experimental restoration project. In Ecological Management & Restoration (pp. 112-125).

Figures 1 & 2 – Adapted from Google Maps data

Figure 3 – Map found on my personal Canberra Nature Map profile

Photographs – Gareth Quirke, October 2016

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About Biodiversity Conservation Blog

I am an Associate Professor at The Australian National University and convene a (very awesome) course called Biodiversity Conservation. Myself and students in the course contribute to this blog.
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One Response to Unintentional Victims of the Predator Proof Fence

  1. Thanks Gareth. It is amazing that so many people are keen to volunteer for work such as this – and I know from experience that picking-up an Eastern Long-necked Turtle can be a stinky affair! Phil

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