Friday, 25 September 2015

Its Orchid-swapping time

About 3 weeks ago I posted about the emergence in 2015 of Cyanicula caerulens on our block.  I have been checking the number of flowers each day (that we have been around) since.  After our trip to Lake Cargelligo caused a brief hiatus, my visit to the orchids yesterday was the finale for the year: only about half the number found and quite a lot of them were very sorry.  So its time for a comparison with last year.

Before doing that here is a picture for those who don't know what a Cyanicula caerulens looks like!
There are 3 main sites for the plants on the block, plus a few outliers.  When I posted about these flowers last year an emailed comment was positive about it saying that it formed a good benchmark.

Once one has a benchmark, one compares things to it!  So, this chart shows the total number of flowers I counted in 2014 and 2015.
I have used a 4th order polynomial to summarise the data: the values of R2;above 0.9,  suggest the curve fits the data pretty well.  Several points emerge from this:
  • the first flowers were observed a little later in 2015;
  • the maximum number of flowers noted was a lot less in 2015; and 
  • the cessation was more 'gentle' in 2015.
As with last year the 'core' site presented the greatest number of flowers.  In the chart below I have used the concept of a flower-day, being 1 flower for 1 day - a flower that lasts for 10 days scores 10!
Although I don't have rigorous data on this aspect the extent of the core site was smaller in 2015 than in 2014.  It is approximated in this graphic with the red line bounding 2014 and the green line, 2015.
The area between the lines is much more densely covered with Kunzea ericoides than the 2015 area, but I think I would have noticed orchids in the fringe area (perhaps a core is like a promise, although a non-core-core sounds like a choking corvid).

I suspect trying to do more with these data would be going well beyond the limits of the data set.  Not to mention the limits of my ability!

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