Bird’s nests and pyramids

I went out yesterday to answer a question that had been on my mind for a while; do we still have Early-purple orchids on Ashdown Forest? As part of my job I monitor a number of the rarer plant species on the Forest, of which several are orchids, but the Early-purple had not been, until now, on my list.

There are records from 20 years ago, with a grid reference, so armed with a GPS I blundered about in the woods for a while, concerned that the habitat didn’t look at all suitable. And then, as almost always happens, just as I was about to give up I spotted three tall, purple spikes in the dappled shade of an otherwise bare woodland floor. Having taken their photograph, I stood up, looked around and realised that I was on the edge of a big population; in the end I counted over 200 flower spikes, and there were many more young seedlings yet to reach flowering size.

EarlyPurple3

Moments like that have always been special for me. I’ll put my hand up here and admit to being a bit of a plant ‘twitcher’, and certainly an orchid enthusiast. So having to monitor orchids as part of my job is a bit of a dream come true.

But just how many orchid species are there on Ashdown Forest? Lowland heathland isn’t generally known for its orchids; chalk grassland, at the other end of the pH spectrum, is the classic orchid habitat.

Chalk and limestone species are sometimes found on the Forest, usually on roadsides and almost certainly as the result of the dumping of limestone by highways contractors. Pyramidal orchid, for instance, turned up last year right at the edge of the verge on a major route across the Forest.

PyramidalOrchid3

Most of our orchid species, however, are naturally occurring and appropriate to the soils and geology of the Forest. They fall into two broad groups, reflecting the two main habitats of the Forest – woodland and heathland.

The Early-purple orchid, discussed earlier, is very much a woodland species, at least in this part of the world. Another woodland specialist is the Bird’s-nest orchid. All orchids have a symbiotic relationship with fungi in the soil, with the fungus supplying nutrients to the orchid that it wouldn’t otherwise be able to access. The Bird’s-nest orchid takes this relationship to the limit; it has lost all its leaves, all its chlorophyll in fact, and gets 100% of its nutrients from its fungal partner. This means that it is only visible above ground when in flower, and even then the flower spike is pretty inconspicuous.

Neottia3

The heathland orchids are rather showier. The commonest by far is the Heath spotted-orchid, found in open, damp areas across most of the Forest. It comes in a range of colour forms, from dark pink through to pure white.

Last year, much to the excitement of orchid enthusiasts, it produced a hybrid with our rarest orchid, the Heath fragrant orchid. There are thought to be only twelve populations of the Heath fragrant orchid in the UK, with the next nearest being on the South Downs, so opportunities for it to hybridize with other orchid species are limited.

FragrantOrchid1

As is often the case, the hybrid shares characteristics of both its parents.

FragrantHeathSpottedHybrid

The last species I want to cover (there are others, some so rare it is unclear if they still occur on the Forest) is a true acid heathland specialist, found out in the remote, wet Sphagnum bogs – Early marsh orchid. It was long known from a single patch which had been protected from grazing with a low fence. I went in search of it last year, and was disturbed to find that it had vanished from its fenced enclosure. I was relieved to find a few scattered plants just outside the fence, then delighted to discover, after some wandering, that the bulk of the population seem to have upped sticks and moved a few hundred metres away to a new bog, where the plants seemed to be thriving.

EarlyMarshOrchid3

As with many of the species that make Ashdown Forest special, our orchids all have very specific habitat requirements, and the majority of them rely on management, in particular grazing, to prevent their open habitats reverting to scrub. I will continue to monitor their progress; it’s a dirty job, but someone’s got to do it!

 

Steve Alton

Conservation Officer