Thursday, 20 July 2017

July Moths, Relief from Helleborine-spotting

I think I am correct in saying that there are no records of helleborines near Hook Norton and therefore we have been travelling far and wide for much of July tracking down these orchids wherever they might be to get good digital images and a leaf slivver, where allowed, from each species to look at the characteristics microscopically. Lytham in Lancashire and Ainsdale in Merseyside for Dune, Green-flowered, and Marsh Helleborines, Gait Barrows in Cumbria for Dark-red Helleborine (gone over), Chilterns (Homefield Wood and Warburg) for Broad-leaved Helleborine.  Staying in the Chilterns, Narrow-lipped Helleborine has proved elusive, and a plant in bud 10 days previously had already gone over when I visited last Monday, whilst some Violet Helleborine plants have remained stubbornly in bud.
Dune Helleborine (E. dunensis)
Green-flowered Helleborine (E. phyllanthes)

Broad-leaved Helleborine (E. helleborine)

Marsh Helleborine (E. palustris)

Back at home we are really pleased with the garden pond we created just last September.  Stocked with a few native plants, and populated with a few dippings from a pond in a nearby field  we have had three frogs together, and there are growing tadpoles, but  favourite  are the Smooth Newts which have taken up residence.  Now we also have a few young newts - 'newtlets' if  that is the correct word.  A minor disappointment is that we have not had any damselflies or dragonflies yet however.

Almost as a distraction I have run the moth trap overnight, twice in the month, both nights being warm and still.  The counts were large, 151 moths of 50 species at the beginning of the month, and this week even more, 248 moths of 61 species.  Even then there were quite a few escapees when I came to inspect, especially Yellow Underwings.  The total species count for the year to date is now 119, including the more challenging micromoth category.  A few chosen almost at random.

Burnished Brass

Brown-line Bright-eye

Dark-barred Twin-spot Carpet

Ruby Tiger

Wednesday, 5 July 2017

Greater Butterfly Orchids in the Chilterns - Fruiting

Down in the Chilterns, a farmer with a strong interest in wildlife has turned over some of his less productive arable fields to wild flower hay meadows.   He is quite passionate about orchids, and in an adjoining woodland there is a thriving population of Greater butterfly orchids (Platanthera chlorantha), which he found a few years ago.   The numbers have increased over those years with a modest degree of management.

I have been fortunate to be allowed free rein on starting a study of the plants, which hopefully will lead to a long term demographic study. The plants are in two patches around 75 yards apart, separated by a forest track, and the farmer has enclosed each group with a four foot fence to keep out deer (conveniently the North and South enclosures)  The canopy, of hazel and beech, shades the plants to quite a degree and we made some measures of the light levels.  Bramble and Dog's mercury surround the orchids.
Plant #89

Plant #89 in Fruit

Plant #84

Plant #84 in Fruit
So far we have marked just about all the plants - flowering and non-flowering - with a total of 343 plants.   We measured the leaf width of the non-flowering plants, and for those that flowered we measured the height, leaf width, spur length, and number of flowers.   Last week we went back to count the number of fruits on  the plants that flowered.  The fruiting success was 31.7% in the Southern enclosure and 28.0% in the Northern enclosure, though I don't think the difference is statistically significant, because the fruiting success of individual plants ranged from zero to in one case, 100%.    By comparison the 5-year average on Skye was 28.6%, plants out in the open in a quite different environment.

Analysis will follow, but an early observation is that the fruiting success of the earliest flowering plants was much the same as those that flowered a couple of weeks later.