Friends of the Box-Ironbark Forests

The August meeting of the Castlemaine Field Naturalists Club featured a talk by Ern Perkins on systematic environmental monitoring over time: ‘the only effective way of measuring change.’ The following report is based on a more detailed account in the CFNC newsletter, Castlemaine Naturalist.

CFNC have been doing systematic monitoring of birds and vegetation for many years using photo points, GPS locations and counts. For birds, they have been following the method proposed by the Australia Bird Atlas: using a fixed area of 2 ha, and recording a session for 20 minutes per month. Ern and Lesley Perkins have established 14 locations and over the years have totted up 1285 visits. In that time, some bird populations have stayed fairly constant [Magpies, Little Ravens Galahs, Cockatoos, Red Wattlebirds and Crimson Rosellas]. For others there is a persistent downward trend, both in species and in numbers: for example, the Southern Whiteface was common at the start of the process, and is now very rare. Decline of bushy understorey is a key in this decline, and the long drought is obviously part of the explanation for this. The decline in numbers is not so evident in urban areas, where trees may be in better condition, though the prevalence of cats makes this a high risk area.

Daltons Track burn zone, September 2012, after a DSE burn in 2011: 'Asset Protection' zones like this one will not get enough time to recover from frequent severe burns.

On vegetation, Ern and Lesley and other CFNC members regularly survey 115 quadrats. A number of these were set up in and outside DSE control burn areas for comparison over time. Although caution is necessary in interpreting the results, Ern was categoric that successful post fire regeneration in a drought year is close to zero. Further, there is evidence of considerable increase in weeds after burns. Sometimes burns are followed by apparently flourishing regrowth  which quickly dies off. Further long term research is necessary to establish more reliable data. In particular, Ern pointed out that the effect of repeated fire on invertebrates, the basis of the food chain, is a complete unknown.

The Castlemaine Naturalist can be got by contacting CFNC at Box 324 or through the club website. At the next CFNC meeting Cassia Read will talk on biological soil crusts: ‘miniature wonderlands of the dry country: what you miss when you don’t walk on your knees.’ [Friday September 14 at 7.30, Uniting Church Hall, Lyttleton St].

The beautiful creature pictured below is an early instar caterpillar, from the genus Doratifera, probably Doratifera oxleyi. These moths are commonly called cup moths. It was found in suspended by a thread in an area of severely damaged bushland in the Diggings Park this week.

Cup moth caterpillar: It’s less than a centimetre long, and you can’t deny it’s pretty— but don’t touch it! We’re not sure if it’s the creature that’s eating our bushland. Photo: Bronwyn Silver, 14 August 2012

Cup moths Cup moths ‘belong to a small group of moths that have unusual slug-like caterpillars that are often beautifully marked and coloured. They derive their name from the cup shaped cocoons made by the caterpillars when they pupate. There are several different species of cup moth that feed on eucalypts and other native plants. The caterpillars differ in colour, pattern and size but they all have the characteristic slug-like appearance with clusters of spines on their bodies. The spines can inflict a sharp and painful sting, rather like a nettle and the caterpillars are often known as ‘stingers’.  The stings may cause local inflammation if they touch bare skin.’ [ref: Department of Primary Industry, SA]

We mistakenly reported last week that the enormous damage inflicted on eucalypts in the south end of the Shire was caused by lerps. Now we believe that the damage is caused by a leaf miner of some sort, and have suspicions about the cup moth–but we’re not sure. Theories are invited.

Porcupine Ridge Road: eucalypts in the South of the Shire are being devastated by a leaf eating creature. Photo: Bronwyn Silver, 14 August 2012

Visitors passing along the Porcupine Ridge Road in recent weeks have noticed that trees on both sides of the road, both in the National Heritage Park and the Upper Loddon State Forest, are looking extremely stressed, presenting a desolate sight.  The cause appears to be a plague of lerps. Such a plague usually reflects a decline in the number of woodland birds which normally feed on lerps. [SEE OUR AUGUST 16 REVISION OF THIS ASSESSMENT]

Distressed trees near the Helge Track: bush health is dependent on biodiversity, and low bird numbers suggest that we may be in trouble.

This decline is alarming from many points of view. The current condition of this bush is an indicator of the connection between biodiversity and forest health. Castlemaine Field Naturalists report that the ‘decline in bushland birds is alarming.’ Their

Lerp attack: the absence of woodland birds is not just a problem for bird watchers.

monthly bird counts at the Spring Gully/Fryerstown Road intersection reveal that the number of species seen, and the number in each species, have been declining for some time. The counts for 2012 are
January nil
February nil
March nil
April Scarlet Robin (1)
May Aust Raven (1)
June nil
July nil
August nil’.

DSE draft fire operations plans propose big burns to the south and west of this area [see our report below].