During countless hours spent studying at the university library, I’d wondered what it would be like to work outdoors again, as I stare out at the sunny early-October day.  I remembered an old Banjo Patterson poem – Clancy of the Overflow – and could sympathise with the city dweller, who romanticises the rural life.  I began to wish I could be outside, in a nature reserve, a national park, or even a wildlife sanctuary; instead I tried to enjoy the sun vicariously through a third-floor window.

Before too long, I’d signed up for two days’ work with Conservation Volunteers Australia (CVA), in the mid-October of 2016 – my first experience working as a volunteer, particularly for an organisation such as CVA.  With no ideas or expectations of things to come, it seems I’d got my wish – I met the small CVA group, piled into the back of a troop-carrier, and headed off for a sunny day’s work at the Isaacs Ridge Nature Reserve, shown on the map below:

Figure 1 – Aerial extent of the Isaacs Ridge Nature Reserve, which includes the Isaacs Pines Recreation Area and various walking, cycling and equestrian trails (shown in the inset, adapted from Watson 2015).

The reserve covers roughly 1.02km² in southern Canberra, and is characterised by a prominent north-south ridge, stretching from Mt Stanley (842m tall, to the south) up to Mt Mugga Mugga (812m, to the north).  The western side of the ridge has been cleared for forestry in the past, and is dominated by replanted Radiata Pines (Pinus radiata), adjacent to the suburbs of Isaacs, Farrer and O’malley.  The eastern side of the ridge is dominated by Scribbly Gum/Red Box (Eucalyptus Rossii/Eucalyptus Polyanthemos) woodlands on the hillside, with areas of the critically endangered Yellow Box/Redgum (E. melliodora/E.blakelyi) grassy woodland on the lower slopes (Southern Act Catchment Group, 2014).  The eastern boundary of the reserve is marked by Mugga Lane, and the neighbouring Mugga Lane Resource Management Centre (the tip), quarries and agricultural land (mainly used for grazing).

Upon arrival, we met Michael Sim, the coordinator for the Isaacs Ridge/Mt Mugga Mugga ParkCare (one of the ACT’s youngest ParkCare groups), and were introduced to the enemy – Sweet Briar or Briar’s Rose (Rosa rubignosa), which had taken over large parts of the eastern slopes of Mt Stanley (shown below in figure 2), along with smaller populations of Hawthorn (Crataegus monogyna) and Firethorn (Pyracantha spp.).

Figure 2 – Map of the Sweet Briar infestation area (outlined in red), in the Isaacs Ridge Nature Park (outlined in blue)

These species are key woody weeds in the ACT, as they are highly invasive (in disturbed landscapes) and form thickets that stop native species from establishing.  Mature plants have thorns which help to prevent grazing by native species, and so they are able to grow unchecked, while currawongs and many other bird species eat the fruits of sweet briar and spread seeds (Hatton, 1989).  The thickets also provide shelter for feral species such as foxes and rabbits, but can also provide safe habitat for smaller native birds (Michael Sim, pers. comm.)

The task at hand was to remove Briar’s Rose, Firethorn and Hawthorn using the “cut and paint” method – the plants were cut at the base of the stem or trunk, using loppers, and then a dilute Glycophosphate (Roundup) solution, mixed with red vegetable dye, was painted onto the stumps to prevent regrowth.  The herbicide was applied within 20 seconds of making a cut, before the sapwood could seal over.  This method is preferred over spraying as it generally avoids impacts on non-target species, provided that the method is used on a non-rainy day (otherwise the herbicide is susceptible to washing off, and affecting non-target species).

Figure 3 – Sweet briar (Rosa rubiginosa), and the tools used for the “cut and paint” method

Figure 3 – Sweet briar (Rosa rubiginosa), and the tools used for the “cut and paint” method

Figure 3 – Sweet briar (Rosa rubiginosa), and the tools used for the “cut and paint” method.

The ongoing hard work of the Isaacs Ridge/Mt Mugga Mugga ParkCare Group and CVA has been invaluable in controlling Briar’s Rose in the reserve, however it is unlikely that the infestation will be removed entirely, due to the difficulty of removing suckers.  So, management efforts will need to be ongoing, to keep populations in check, and will incorporate more cut-and-paint control, and weed surveillance to monitor population numbers and distribution (Michael Sim, pers. comm; ACT Environment and Planning Directorate, 2014).

I was left feeling overwhelmed by the amount of work which lay in store for Michael the IRMMM ParkCare Group, but it was clear how powerful these organisations could be in improving land management in nature reserves and urban open spaces.  It was also inspiring to see members of the community taking a sense of pride and stewardship in the land!

We left the reserve feeling exhausted, but satisfied after a day’s work.

A few days later, we headed out with the CVA team to the Tidbinbilla Nature Reserve, to the south of Canberra.  The this time, the weather was not so kind – cloudy skies and constant rain awaited us at the reserve.  We donned some hi-vis raincoats and headed to The Sanctuary for a day of track maintenance and sign cleaning (these stylish coats are shown below!).

Figure 4 – Searching for woody debris on trails within Tidbinbilla’s Wildlife Sanctuary

High rainfall in the preceding month (the second-wettest September on record, according to BOM, 2016!) had saturated the soil within the reserve, and so the trails were covered in overland flow debris and fallen timber.  Track maintenance involved the removal of woody debris, and cleaning mould off trail signs.  After the day of cleaning trails, we gained a newfound appreciation for the effort required to maintain nature reserves and wildlife sanctuaries, particularly in a climate of weather extremes.

The sanctuary forms part of the larger 54.5km² Tidbinbilla Reserve (TAMS 2012) – a protected area on the western lower-slopes of the Brindabella Mountains – and is encompassed by exclusion fencing to keep feral species out.  Thanks to the exclusion fencing, the sanctuary provides important habitat for the Eastern Bettong – an insurance population for the Mulligan’s Flat Bettong project.  The Sanctuary also provides habitat for the Critically endangered Southern Brush-tailed Rock-wallaby, and the Northern Corroboree Frog.

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References

ACT Government – Environment and Planning Directorate, 2014.  2014 Review of the ACT Weeds Strategy 2009-2019.  Available from http://www.environment.act.gov.au/__data/assets
/pdf_file/0004/722092/Weeds-strategy-summary-of-achievements.pdf (accessed 26 October 2016)

ACT Government Territory and Municipal Services (TAMS), 2012.  Planning and Development (Tidbinbilla) Plan of Management 2012.  ACT Territory and Municipal Services Directorate, Canberra.

Australian Government Bureau of Meteorology, 2016.  Canberra in September 2016: Second-wettest September on record.  Available from http://www.bom.gov.au/climate/current/month/
act/summary.shtml (accessed 26 October 2016)

Hatton, T., 1989.  Spatial patterning of sweet briar (Rosa rubiginosa) by two vertebrate species.  In Austral Ecology 14(2): 199 – 205

Southern ACT Catchment Group, 2014.  Isaacs Ridge Mount Mugga Mugga Park Care Group.  Available from http://sactcg.org.au/members/current_members/isaacs_ridge%20
mount_mugga%20mugga_park_care_group (accessed 25 October 2016)

Watson, H., 2015.  Consultation Report:  Isaacs Ridge Mountain Bike Trail Upgrade Project.  Report prepared for ACT TAMS by Canberra Town Planning, ACT.  Available from http://www.environment.act.gov.au/__data/assets/pdf_file/0009/906462/Consultation-Report_IsaacsRidgeTrailsCanberraTownPlanning_FINAL_150930.pdf