On the hunt for tiny wetland plants

Loch Lomond NNR

Amongst the larger attention-grabbing species of Loch Lomond NNR, such as ospreys, eagles, otters and, for the botanists – the rare Scottish Dock (Rumex aquaticus), there are some lesser known treasures along the shores of Crom Mhin.

Looking for submerged tiny plants through a bathyscope.

The vascular plant assemblage of the Endrick mouth and Loch Lomond islands is of particular importance and a designated feature of the SSSI. The assemblage is monitored every few years, meaning we get to don our dry-suits/waders and paddle out to look for some teeny tiny rarities.

Eleocharis acicularis (Needle Spike-rush)

Needle Spike-rush (Eleocharis acicularis) creating a lawn across the flats of the Endrick mouth.

Callitriche palustris (Narrow fruited Water-starwort)

The little black fruits of Callitriche palustris

Elatine hydropiper (Eight-stamened Waterwort)

Elatine hydropiper. To identify down to species, a very close look at the fruits (little brown blobs) is required.

Elatine hexandra (Six-stamened Waterwort)

The view through the bathyscope, looking at Elatine hexandra

It takes a good botanist’s eye to confidently identify these species, but even as an amateur once you get your eye in you start seeing them everywhere.

These rare plants require shallow waters and/or damp silt on the edges of water bodies and we have found a good number of stands and individual patches of each.

However, they are not without threat. Having such niche requirements to thrive, they cannot spread easily across the nature reserve to allow for some expendability from cows trampling over them. Also, the narrow habitat of the silty, flat edges of the Endrick mouth can change quite dramatically with rising or lowering water levels.

This having been such an incredibly dry summer, we’re seeing much more sand exposed than normal. In a way, this creates a larger area for the partially-terrestrial plants to spread, but it also means it is perfect for other species to rear their head…

Crassula helmsii (New Zealand Pygmy Weed)

Ahh, crassula. It’s become a bit of an expletive around the NNR team. It’s actually quite an attractive little plant, but then again a lot of the invasive plant species we deal with regularly were once (some still are) celebrated for their exotic beauty.

This Crassula is an invasive freshwater shore plant. It only comes out when the water levels allow it to – and with the low levels this summer it’s having a field day and has appeared right where our lovely rare plants are.

If allowed, it will take over the shore, so we’ve been heading out with buckets and spades to dig up every plant we can find. Some plants are so small they could easily be missed. It helps to channel the inner child and crawl along on hands and knees, scanning the sand for little clumps smaller than a 5p coin and even smaller fragments.

Diggin up invasive plants on the newly-christened ‘Crassula island’ or ‘Isle de Crassula

There are some spits of sand just west of Crom Mhin and the Endrick mouth. Many waders and geese enjoy these little ‘islands’ each year and, with the water levels being so low, we’ve been able to wade out in our dry suits to check them out. The islands, that is – we don’t condone trying to get up too close to wildlife. Although, the first time we went out to the islands, a group of around 8 ringed plovers were milling around, seemingly unbothered by our presence!

Of course, these islands have got bigger this year and have exposed more sand. What does this mean? Yep, more Crassula!

It also means it’s gonna take an awful lot of rainfall to bring the loch back to a normal state. The ‘islands’ have been exposed for so long, terrestrial species such as willows have started to establish on them. The islands may even become a permanent fixture in the landscape, if and when the levels rise, as sediment accumulates around the plants and the roots start to bind it all together.

With ever-changing levels, perhaps some day those trees will look a bit like these ones we found along the shore:

It’s been a while since the water was at the level of those tree roots!

Last summer (the really rainy, thundery summer. Remember that?) the water level was waaaay higher. So much higher that Crom Mhin was almost entirely flooded. There wouldv’e been no way to survey the tiny plants or even access the shore. Just shows the difference in a year and how majorly this can influence the landscape and wildlife.

About Ellie Lawson, NNR Placement

Practical Placement on Stirling's NNRs. Enthusiastic about birds, butterflies, bogs, brochs... and the rest!
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1 Response to On the hunt for tiny wetland plants

  1. Anne says:

    This is very interesting.


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