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Bee orchid at Monk's Wood, Cambs.
Image: Kevin Walker |
In recent months Dr Kevin Walker, BSBI Head of Science, has been focusing on a different wild flower each month. In March it was purple saxifrage, in April it was snake's-head fritillary, May's Wildflower of the Month was meadow saxifrage, and now Kevin focuses on a plant we usually think of as blooming in June on calcareous grasslands in the south. Except that's no longer the whole story...
Read on to find out what Kevin has discovered about one of our most popular and iconic orchids!
"Orchids are our most glamorous wildflowers. They are an
entry point for generations of botanists and even pique the attention of birders
when the flow of spring migrants dwindles to a slow trickle in late May. Their exquisite
beauty, complex
sex lives and often extreme rarity gives them an allure that is hard to
resist and can lead to life-long obsessions. As BSBI member Leif Bersweden captures so
beautifully in The
Orchid Hunter, it was the discovery of a Bee Orchid as a boy that got him
hooked. Leif is in good company. Charles Darwin devoted much of his later life
to the “various contrivances by which British and foreign orchids are
fertilised by insects” – a book with superb descriptions and line drawings of
the fascinating sex lives of many British species.
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What's the collective noun for bee orchids:
a swarm?
Image: Rebecca Wheeler |
"June is the premier month for orchid hunting. Many of our c50
species flower in quick succession and, if you are lucky enough to know
where to look, there are well trodden paths to all but the very rarest species.
Wisely, the hallowed locations of the likes of Lady’s-slipper, Red Helleborine
and the ethereal Ghost
Orchid remain under wraps. The most talked about orchid of them all is the Bee Orchid Ophrys
apifera. This colourful mimic, with its bee-like flowers, is one of our
most widespread orchids and increasingly the one you are most likely to find
closest to home.
"Historically its beautiful blooms were to be searched for in
chalk downland, coastal dunes and damp meadows and pastures. But today it is as
likely to be encountered on urban road verges and waste ground, or as a
colonist of quarries and gravel pits in the early years of succession to more
stable grassland and scrub. If you live in England and have never seen one then
ask around. Most botanists will know where to find one.
"The fortunes of the Bee Orchid are worthy of a book in
itself. It appears to be on the move both ecologically and geographically and
these changes are providing tantalising insights into how our environment is
changing; if these early indications are correct, it may well be the ‘canary in
the cage’ when it comes to climate change and plant conservation.
Close to home…
"One of the wildlife highlights of these long lockdown months
has been the abundance of wildflowers in urban areas where councils have
relaxed their mowing regimes. This, combined with Plantlife’s #NoMowMay
campaign, has led to a surge in records of Bee Orchid. Since it was first
reported in flower on the 15th of May by Dr Richard Bate, Twitter has been alive with records,
many from garden lawns: participants in the BSBI’s Garden Wildflower Hunt have
been sending
us records of bee orchid sightings in their gardens and telling us how
delighted they were to welcome these visitors!
"My nearest colony is about fifty metres from my front door.
I’ve been keeping a close eye on this little colony and these observations have
been very revealing. The first thing to note is that it is flourishing on a
very ordinary roadside verge which can only be described as a billiard table. Most
of the plants rarely, if ever, get a chance to flower; those that do have to
endure football games and mowers and this year a severe frost in late April followed
by a month-long drought in May. Many blackened off and died back. A few have
flowered probably a week earlier than normal. Flowers first appeared on “my”
bee orchids on the 2nd of June. In normal years (whatever that now means!),
they are usually at their peak between 9th to 24th June. Anecdotally botanists
tell me that it was never worth looking for their flowers before mid-June.
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A meadow full of bee orchids and other
native wildflowers
Image: Rebecca Wheeler |
"What’s also revealing about “my” colony is its location.
It’s not particularly special – just some grass strips in a modern housing estate
built on a former MoD site in the 1990s. The grassland, which is not totally
devoid of interest (Knotted Clover
Trifolium striatum grows with the bee orchids), could have survived the
construction work or was possibly seeded afresh, creating ideal conditions for
Bee Orchid – which likes bare ground - to colonise.
"So it is not surprising that we are getting lots of reports
of Bee Orchids in garden lawns. This reminds me of another orchid that made a
spectacular appearance in gardens after the scorching summer of 1957. Severe
drought meant that many lawns were left uncut and this led to flurry of reports
of Autumn
Ladies-tresses Spiranthes spiralis from gardens, so much so that it was
reported in The Times. This mass seeding event lead to a dramatic increase in
populations in subsequent decades, so perhaps an unintended consequence of this
lockdown will be a similar increase in Bee Orchid colonies in years to come?
Spreading north…
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Graph showing northward spread of
bee orchid over time
Graph by Kevin Walker |
"Scientists have shown, unequivocally, that some butterflies,
dragonflies and birds are expanding their ranges northwards as climate change
opens up new areas of habitat to them. Evidence for plants is much harder to
come by: maybe that’s not that surprising. Wildflowers are by nature sedentary;
they don’t move much and if they do, their dispersal is measured in metres
rather than kilometres. The main exceptions are orchids. Each flower produces
thousands of dust-like seeds and these can be dispersed over large distances by
air currents. It has even been suggested that the North American orchid known
as Irish
Lady’s-tresses Spiranthes romanzoffiana, a rare plant of the western
seaboard of Britain and Ireland, might have been blown across the Atlantic
during gales. The attractive Mediterranean tongue orchid Serapias lingua appeared
in Essex a few years ago and again wind dispersal has been mooted as the means
by which it arrived on our shores. In both cases there are other theories but
the most parsimonious would seem to be wind.
"Of all the British orchids, Bee Orchid has shown the most
spectacular increase in recent decades. Back in the 1960s, it was largely
confined to grassland in southern and south-eastern England with odd
records stretching as far north as County Durham. Since then it has been
gradually extending its range northwards (see the graph above) especially in northeast
England where it has spread along the coast. It was first recorded in Scotland
in 2003 and now occurs as far north as Glasgow and Edinburgh, and I’m sure it
will spread further, probably in sandy grassland along eastern and western
coastlines, in the not too distant future.
"As intimated above it also appears to be broadening its
ecology. In the first edition of Clapham, Tutin and Warburg’s Flora of the British Isles, published in 1952, its habitats were described as “pastures,
field-borders, banks and copses on chalk or limestone, especially on recently
disturbed soils; also on base-rich clays and calcareous dunes.” Today you are
as likely to see it off calcareous soils as on them, on roadside verges, spoil
heaps, urban waste ground, disturbed soils in old quarries and gravel pits and
abandoned farmland.
Seeds of its success…
"So what is the secret of the Bee Orchid’s success when so
many other wildflowers have declined? Despite its bee-like appearance,
self-fertilisation appears to be the norm rather than deception to entice
cross-pollination by bees (as in other Ophrys species). Unlike some other
orchids, individuals can continue to flower for a number of years. As a
consequence, populations are likely to grow very quickly. This coupled with its
ability to spread its seed far and wide means that it can quickly colonise new
habitats as they come within reach.
"Like most plants, orchids face a trade-off when it comes to
seed size. Dust-like seeds are great for getting around but do not have enough food
to support the growing embryo once they land. Many orchids strike a deal with soil
mycorrhizae gaining nutrients from the fungus as they grow. But this is the
Achilles heel of many orchids species and the reason they are so rare; highly
specialised relationships severely restrict where they can grow. We can only
assume that the Bee Orchid has chosen a range of very widespread and common
fungi with which to share its food.
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Bee orchid rosette with 20p coin
standing in for a scale bar
Image: Kevin Walker |
"But possibly at the root of its success has been its ability
to adapt to rising temperatures in recent decades. Bee Orchids are wintergreen;
in fact, winter is the easiest time to spot their distinctive rosettes. Many
participants in BSBI’s New Year
Plant Hunt spot the rosettes while they are out looking for wild plants
blooming in midwinter. Mike Waller’s Beginner’s
Vegetative Guide to Orchids of the British Isles is very helpful for anyone
who isn’t sure what to look for. As our winters have become less severe, Bee
Orchids have clearly benefited especially in urban and coastal areas, where severe
frosts are less common.
"We humans have accentuated these trends by creating the disturbed,
early successional conditions that they seem to love. Since the 1950s we have
transformed our lowland landscapes through a massive expansion in road and rail
networks, industrial land, waste ground, restored colliery and landfill, and
abandoned quarries and gravel pits. Bee Orchids have benefited from these
transformations.
"So the Bee Orchid is probably the nearest wildflower
we have to a ‘canary in the cage’; its fortunes tell us much about how our
climate and landscapes are changing. But more than that, this adaptable little orchid
continues to enthrall and excite us; as the celebrated and much-loved illustrator Cicely Mary Barker
observed in her ‘Song of the bee orchis fairy’, a day when you discover a Bee
Orchid is always 'your luckiest day'!”
