Philip,
I do apologies for not being specific and including a longer time period.
You have made some good points. I agree reporting rate is not abundance but
I did not suggest that it was, just that the reporting rate had declined and
thus we should think about the implications of this. Habitat is not
something I can apply to the COG data at the moment. The closest I can get
is to provide the data by gridcell.
I have been working on a way to compare two sets of COG data for a couple of
weeks and this discussion seems like an appropriate point to introduce one
or two of the outputs even though they are still under development and a bit
rough.
The table below shows the % difference in reporting rate for EYR general
database records (excludes the GBS data) between two 5 year periods:
1992-1996 and 2008-2012. The table is divided into COG gridcells (A01 at top
left and Z30 at bottom right). Where a number appears in the table, it
indicates that there are datasheets for both periods and that EYR has been
reported in either or both periods. The number is the percentage change in
the reporting rate. ([RR% for 2008 to2012 minus RR% for 1992 to 1996]/RR%
for 1992 to 1996 times 100). Gridcells without datasheets in both periods
have no numbers in them. The red highlights are gridcells where the RR has
decreased by 25% or more and the green is where it has increased by 25% or
more (green with 100 is a gridcell where EYR was not reported in 1992-1996
but were in 2008-2012). A black background indicates it was reported in
1992-1996 but not in 2008-1012.
Of the 139 gridcells, 78 (56%) show a decrease of 25% or more, 47 (34%) show
an increase of 25% or more and 14 (10%) are between -25% and 25% (5
increase, 9 decrease). EYR was not reported in 40 gridcells in which it was
recorded in 1992-1996 (29%) and was reported in 40 new gridcells (green with
100)
The attached map shows these data with the number of sheets as a highlight
of each gridcell; the darker it is the more sheets are present in each
period. Scope 1 is as below, 2008-2012. If a cell is highlighted but does
not have a red or green circle it means the change was in the -25% to 25%
range. A "X" over a red circle indicates no reports in 2008-2012, while a
"+" over a green circle indicates that EYR was not reported in that gridcell
in 1992-1996.
I realise these tables and maps are a bit complex at the moment but I hope
this is enough explanation to understand what is being presented.
At the moment I do not have any analysis of the statistical significance of
these changes built into the presentation.
Steve
Difference Scope 1 Scope 2
Species Eastern Yellow Robin Eastern Yellow Robin
Year(s) ending 30 June 2008 2009 2010 2011 2012 1992 1993 1994
1995 1996
Survey Type (Multiple Items) (Multiple Items)
Reporting Rate difference where there are sheets in both periods
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
01 100.0
02 -100.0 -100.0
03 -100.0
04 -100.0 100.0 2.8 100.0
05
06 -100.0
07
08 -0.3 100.0 100.0
09
10 100.0 -89.9 100.0 100.0
11 100.0 -15.4 -77.2 100.0 100.0
12 -52.1 -52.3 -100.0 -100.0 -74.9 100.0 100.0
100.0
13 100.0 -100.0 -89.1 -94.4 -20.1 -49.0 100.0 100.0 -100.0
14 -42.2
0 -100.0 -100.0 -91.2 -25.5 -94.1 -23.2 -89.7
15 -27.4
14.8 -58.8 -87.0 -100.0 -100.0 -100.0 -100.0 -47.4
-100.0
16 100.0 -22.8 -21.5 9.9 -100.0 100.0 -100.0 161.3
17 -100.0 -62.1 -44.8 -77.2 -100.0 -76.9 -45.0 53.6
100.0 100.0
18 522.5 2.2 -100.0 -59.3
19 -100.0 100.0 -23.2 -100.0 -85.7 100.0 100.0 100.0
51.3 8.3
20 -100.0 -85.3 -59.6 -85.2 -100.0 100.0
-100.0
21 100.0 100.0 -65.6 -57.1 -49.2 100.0 100.0
22 100.0 121.9 -77.2 -100.0 -100.0 -45.5
23 -100.0 100.0 23.7 -36.9 100.0 -65.0 -100.0
24 -100.0 -100.0
-47.8 -100.0 -67.9 -100.0 -100.0 100.0
25 154.4 -74.3 100.0 -100.0
26 74.2 -53.2 100.0 100.0
27 -100.0 -100.0
28 -18.5
29 -100.0
30 -100.0
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