The original Department of Land and Water Conservation (DLWC) Rates of Clearing project had three objectives:

1. Repeat previous >20% canopy cover studies to compare results

2. Complement 1. by developing detection methods for woody vegetation with <20% canopy cover

3. Develop detection methods of clearing of non-woody vegetation including native grasslands.

The first objective has been achieved with the ERIC reports of 1998 and 2001. The technology exists to achieve objective 2 as demonstrated by recent NPWS reports, and current DLWC research is making progress to being able to detect objective 3.

Until we can detect all three types of vegetation structure it will not be possible to produce accurate figures of total clearing of native vegetation.

In March 2001 the Minister for Land and Water Conservation, Mr Amery, announced the results of a study of land clearing in NSW between the years 1997 and 2000. This is known as the ERIC (2001) report. This shows 14,000 hectares of woody vegetation with greater than 20% canopy cover was being cleared annually in NSW.

The Minister emphasised that clearing in NSW had apparently halved from 1997 (32,000 ha) to present day (14,000 ha), ie since the inception of the Native Vegetation Conservation Act in January 1998.

ERIC was probably reasonably accurate for detecting most clearing in eastern NSW (except for some wetlands, grasslands and open woodlands in valleys).

However, it failed to detect most of the clearing where tree cover is naturally sparser.

Two recently-published scientific reports, compiled by NPWS researchers, on clearing in the NSW wheatbelt cast more light on the level of vegetation clearing in NSW. These studies detected clearing to 5% canopy cover — a category which is 15% lower than the ERIC studies.

A paper by Cox et al. (2001), published in the Royal Botanic Gardens ecology journal Cunninghamia, provides an analysis of clearing rates in the northern- most section of the NSW wheatbelt around Moree between 1985 to 2000. This has been followed by a report to the Natural Heritage Trust by Bedward et al. (2001) that detects clearing over a larger section of the wheatbelt from the Queensland border to Forbes in central NSW (excluding a band through Walgett and Narrabri).

A major finding of the NPWS research is that by detecting clearing to 5% canopy cover, they found 10 times the amount of clearing detected by the ERIC methodology in the northern wheatbelt.

The NPWS methodology excluded areas less than 10 ha in size and did not include vegetation with a natural canopy cover of less than 5% (grasslands, sparse shrublands). The results, therefore, are conservative.

Of the 14,000 ha of clearing detected in NSW in the ERIC (2001) report, it appears that about 4000 ha occurred on the western plains where open vegetation prevails.

Multiplying 4000 ha by 10 (based on Bedward) yields 40,000 ha. Add the remaining 10,000 ha of clearing detected by ERIC (2001) from eastern NSW and the result equals 50,000 ha.

Therefore, it can be stated that at least 50,000 ha of woody vegetation with a canopy cover of greater than 5% are being cleared annually in NSW. To gain an estimate of total clearing of native vegetation in NSW, I have estimated the annual rate of clearing of vegetation types with <5% woody canopies. I would estimate this (based on clearing applications approved on DLWC website) to be at least 10,000 ha per year.

What is of great concern from the NPWS analyses is that most of the wheatbelt vegetation is becoming highly fragmented. This will lead to further species extinction over time – about 70 woodland birds are on the brink now!

It cannot be stated with surety that clearing has decreased since the inception of the Native Vegetation Conservation Act in January 1998. While ERIC (1998, 2001) found that there has been a reduction of clearing of dense vegetation on the coast and tablelands, the NPWS wheatbelt clearing data shows opposite trends.

The NPWS data reveals that, overall, clearing has increased in its wheatbelt study area — from 20,180 ha/year from the mid-1980s to1997, to 28,475 ha/year from 1998 to 2000. Clearing has quadrupled in the Nyngan region from 2,142 ha/year before 1998 to 9,014 ha/year since 1998.

Many of the plant communities being cleared in the wheatbelt are among the most threatened ecological communities in NSW. They have been reduced to less than 25% of their pre-clearing extent and are highly fragmented. Some have been reduced to less than 10% of their pre-clearing extent, yet clearing continues.

The NPWS studies have demonstrated that most of the clearing in NSW is happening in open woodlands with a canopy cover of less than 20%. It will be necessary to use methodologies that include all relevant vegetation types if managers are to have reliable figures on which to base land use decisions.

NSW is some way off meeting the no-net-loss position as agreed under the NHT Bushcare Agreement with the Commonwealth Government. At least 60,000 ha are still being cleared, including in regions where very little vegetation remains and where many ecological communities and species are highly endangered.

This article has been modified from an article first published in issue 6 of Hunter Flora by the Hunter Catchment Management Trust

Cox, S.J., Sivertsen, D.P. & Bedward, M. (2001) Clearing of native woody vegetation in the New South Wales northern wheatbelt: extent, rate of loss and implications for biodiversity conservation. Cunninghamia 7(1):101-15.

Environmental Research and Information Consortium Pty. Ltd. (1998) Rates of Clearing of Native Woody Vegetation 1995-1997. Report for the NSW Department of Land and Water Conservation (ERIC: Canberra).

Environmental Research and Information Consortium Pty. Ltd. (2001) Rates of Clearing of Native Woody Vegetation 1997-2000. Report for the NSW Department of Land and Water Conservation (ERIC: Canberra).

John Benson 
Senior Plant Ecologist at the Royal Botanic Gardens Sydney.