During October I have been trying to catch up on analysing data and other information I collected on a few orchid projects during the summer.
One of the more interesting has been the study of a population of Greater Butterfly orchids, made more enjoyable because the landowner is a keen and enthusiastic participant.
I have now finished interpreting this year's data, and while the population is one of the biggest, if not the biggest in Oxfordshire, it is in quite a confined area of woodland in the Chilterns, shaded by beech and ash. All the plants above ground in one half of this orchid patch have numbered markers so we can look at their fate year by year.
Here are a a few highlights from this year (and some photos from the count of flowering plants in June):
There were around 500 plants in 2018 which produced 196 flowering spikes in an area of around 500 m2. The number of plants increased by at least 40% on last year, and the number of flowering spikes by 58%. This year's flowering plants were taller, had larger leaves than those last year, and the fruit set was higher. We are looking at climate influences.
Around 5% of the plants there last year did not appear this year, maybe dead or just dormant. 44% of the plants that flowered in 2017 did so again this year; they were more robust than those that did not repeat flower.
The population was made up by flowering plants (26%), what I term maturing plants with two leaves (26%) and juvenile plants with 1 leaf (48%). The pictures are of the same plant in full flower (June 6), showing the first leaves (April 10), in bud (May 8) and in fruit (Aug 10). Seed dispersal began end August.
Fruit set was more likely for flowers in the middle of the inflorescence rather than the top or bottom.
Much more detail is available in a progress report which can be accessed by following this Dropbox link:
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