ordinary meeting of council to be held on tuesday, 18 july 2006

Attachment 2: Summary Actions
Summary <strong>of</strong> Vegetation Condition for All Catchments from 1997 <strong>to</strong> 2003
The three graphs in Figure 1 <strong>be</strong>low show a comparison <strong>of</strong> <strong>to</strong>tal vegetation condition
(weed mapping) over all three catchments. The area and change in vegetation (weed)
classes is shown in hectares Figures 2 and 3 show percentage change in weed class 4
from 1997 <strong>to</strong> 2003 for both the <strong>to</strong>tal area <strong>of</strong> all catchments and the sum <strong>of</strong> each
catchment respectively. Mapping at this scale is a coarse measure <strong>of</strong> change over time
due <strong>to</strong> bush regeneration works. The inconsistencies <strong>be</strong>tween mapping years due <strong>to</strong>
observer interpretation are smoothed out at such a large area scale (1,100 ha).
The level <strong>of</strong> accuracy <strong>be</strong>tween mapping years and sites depends upon consistency
<strong>be</strong>tween mapping periods which is affected by individual observer interpretation <strong>of</strong>
the weed mapping guidelines. Other fac<strong>to</strong>rs that affect accuracy include availability <strong>of</strong>
reliable reference points, changes in visibility (plant growth), bushfire, and clearing
by residents.
There is a general trend <strong>to</strong>wards less hectares <strong>of</strong> degraded bushland (Classes 4 and 3)
over time (see figures 2 and 3). A decrease in class 4 or 3 will result in an increase in
the area <strong>of</strong> class 2 or 1. That is a decrease in highly degraded areas results in an
increase in area <strong>of</strong> less degraded vegetation classes.
The graph in Figure 4 graph shows a comparison <strong>of</strong> only bush regeneration sites
worked in the Middle Harbour Catchment <strong>be</strong>tween 2002/03 and 2003/04 financial
years. Mapping at this scale, rather than at the whole catchment, can show a finer
level <strong>of</strong> detail and change over time due <strong>to</strong> bush regeneration works.
The level <strong>of</strong> accuracy <strong>be</strong>tween depends upon consistency <strong>be</strong>tween mapping periods
which is affected by individual observer interpretation <strong>of</strong> the weed mapping
guidelines. Other fac<strong>to</strong>rs that affect accuracy include availability <strong>of</strong> reliable reference
points, changes in visibility (plant growth), bushfire, and clearing by residents.
Note. This graph is based data collected from recent trials based on more thorough
mapping <strong>of</strong> regeneration sites only. The data is preliminary at this stage as the
methodology has not <strong>be</strong>en finalised in<strong>to</strong> a form that will give more consistent results.
However, it could <strong>of</strong>fer a higher potential for much more accurate and meaningful
data collection.
As part <strong>of</strong> the 2006/2007 work program existing data and collection pro<strong>to</strong>cols will <strong>be</strong>
reviewed. The aim <strong>of</strong> this process will <strong>be</strong> <strong>to</strong> help ensure consistency <strong>of</strong> data collection
<strong>to</strong> reduce differences and errors <strong>be</strong>tween sampling years, sampling sites, and staff.
Ku-ring-gai Council Summary <strong>of</strong> programs within the Sustainability and Natural
Environment sections 2005/2006
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