Pymble Business Park - Ku-ring-gai Council

13R.2 SUMMARY OF METHODOLOGY
FOR CONVERSATION SIGNIFICANCE
ASSESSMENT - GREENWEB (continued)
13R
Category 3
This includes all vegetation of patch size ≥ 0.1ha in size or vegetation areas of good or moderate
condition within the urban matrix.
The patch size of ≥ 0.1ha, is estimated to include an area of approximately 6 large established trees.
This patch size aligns to the 0.1ha layout of nested 20 × 50 m and 20 × 20 m plots used for the
assessment of vegetation condition, as used within Biobanking (DECC 2008b) and the Biometrics
methodology for assessing clearing and ecological thinning proposals on terrestrial biodiversity under
the Native Vegetation Act 2003 (DECCW 2011).
This patch size is considerably larger than the ‘standard’ plot size (0.04ha) recommended by Native
Vegetation Interim Type Standard for vegetation mapping and identifi cation (Sivertsen 2009 2 ).
Note: A 5ha size threshold is adopted within the Biobanking methodology (DECC 2008a) and the
BGHF listing advice under the EPBC Act (DEWHA 2005). A patch size analysis of Key Vegetation
Communities
≥ 0.1ha as included within Category 3, identifi ed that all patches ≥ 5ha are already mapped within
Category 1 or 2.
These areas assist in the maintenance of TECs across a range of topographies. They also play an
important role as biodiversity reservoirs, providing stepping stone links for fauna and seedbank /
pollination resources to support the survival of remnant vegetation patches.
Small patches can be valuable for native inverterbrates and for some birds (Fischer and Lindenmayer,
2002).Urban street trees for example, provide bird habitat for resting, nesting, feeding and hollow use
(Young et al 2007, Tzilkowski et al 1986, Weleh 1994, Cannon 1999, Chamberlain et al 2004). They
also provide habitat for pollinators, such as bats, that may be less constrained by landscape features
(Aldrich & Hamrick 1998, cited in Sork and Smoise 2006).
Areas included within this category (as well as those identifi ed within biodiversity and riparian corridors)
provide genetic resources from remnant vegetation to support the ecological functions of both
KVCs and non KVCs, and facilitate gene fl ow (reducing genetic erosion / isolation and the effects of
fragmentation).
In urban areas where fragmentation has occurred, the main strategy to fi ght genetic erosion is the
maintenance of a good quality and quantity of gene fl ow among fragments. “Fragmentation does not
necessarily equate to genetic isolation”, Krauss et al states (2007 p396). As long as there is suffi cient
gene fl ow between fragments, species should be able to survive and grow at a distant site. In other
words, even though habitat may be separated, if the quality and frequency of gene fl ow can be
maintained, genetic erosion should not occur. Sork and Smoise (2006) summarized that two elements
measuring the degree of isolation of a fragmented landscape are the quantity of incoming pollen and
the diversity of incoming gene sources.
As such the more connectivity and protection of suffi cient / relevant remnant areas within the urban
area, the higher level resilience or core areas will have.
This category includes trees within KVCs identifi ed as signifi cant during Ku-ring-gai Key Vegetation
Community mapping (KC 2011a and 2011b).
REFERENCES
This included the identifi cation of local native trees; identifi ed as signifi cant due to the presence of
habitat (e.g. a hollow), provision of food for wildlife, and / or exceptional form or size. This mapping
provides an opportunistic selection of signifi cant native trees and is not considered to capture every
signifi cant tree within the urban landscape.
1
The Native Vegetation Interim Type Standard (Sivertsen 2009) addresses the quality and nature of the scientifi c
processes for native vegetation type activities; and applies to all relevant vegetation activities to which the NSW
Government is a signatory or to which the NSW Government makes a fi nancial or in-kind contribution.
Draft Ku-ring-gai Local Centres Development Control Plan 2012
p 191