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Thriving in areas where there is a high annual rainfall with relatively constant temperatures, our temperate rainforests are full of wonder and mossy goodness, capturing imaginations and lifting spirits of visitors.

However, they are more than just woodlands; it’s a mosaic of trees, open glades, crags, ravines, rocks and gorges. With surfaces absolutely bursting with liches, mosses, liverworts and a variety of fungi; they support a vast array of insects, birds and other wildlife, absorb carbon and slow the flow of floodwaters.

What is damaging temperate rainforests in the UK?

Nitrogen gases in air pollution have the potential to destroy these beautiful places. This pollution can take the form of ammonia emissions from farm manures and fertilisers, or nitrogen oxide emissions from fossil fuels.

Even rainforest areas far from the source of pollution, such as the northwest coast of Scotland, are affected by this threat as it can travel long distances in the atmosphere.  

UK Nitrogen depositions map

In fact, data shows that most areas of temperate rainforest in Britain have exceeded what is known as critical load. Critical load refers to the maximum amount of pollutants that something (either a person or habitat) can be exposed to before significant harmful impacts start to occur.

This map shows how the temperate rainforest zone (the area in which we would expect to see temperate rainforest sites) has been impacted by this overabundance of nitrogen from ongoing air pollution. Almost all of the rainforest in England and Wales – and almost half in Scotland – has exceeded the critical load. In total, 66% of the zone has exceeded critical load, and in many areas of England and Wales the overabundance of nitrogen goes way beyond this threshold.

Impacts of nitrogen pollution will soon be evident as trees within the rainforest will temporarily show increased growth from extra nitrogen.

However, in the long term, any growth will soon stagnate as the earth becomes saturated with excess nitrogen (more than 94% of woodlands are affected UK wide!). Higher nitrogen levels mean trees will often suffer from discoloration and increased vulnerability to drought, frost, and disease like acute oak decline.

Woodland fungi are no exception to impacts of air pollution, as many are closely associated with tree roots and health.

Their loss will result in a further decline of tree species, leading to increasing carbon emissions and further contributing to the ongoing climate crisis. 

How does air pollution affect our wild plants?

A change in flora is sure to follow an increase in air pollution as tougher nitrogen-tolerant plants, such as nettles and brambles, will outcompete the more sensitive and specialist species within the rainforest. This has a cascading effect on other wildlife which rely on certain wild plants for food, shelter, and reproduction.  

Losing species which make up a significant part of the rainforest ground cover, such as mosses and liverworts like Greater Whipwort, reduces the ecosystem’s ability to retain water. This makes the whole area more vulnerable to droughts and floods.   

Facing the loss of lichens

As an essential part of temperate rainforests, many lichens are incredibly sensitive to changes in air quality and require low levels of air pollution to thrive. These lichens provide food, shelter and microhabitats for invertebrates, in addition to contributing to carbon cycling and water retention.

Some rare lichen species are only found in rainforest areas and are being pushed to the brink of extinction. Without lichens, our temperate rainforests would struggle even more to survive.

Tree Lungwort Lobaria spp in particular is an amazing indicator species, as its presence signals that the forest is healthy and functioning as it should. This is because it is a slow growing species that is even more sensitive to air pollution than most other lichens.

Tree Lungwort often can become outcompeted and swamped in nitrogen-tolerant algae, knocking the ecosystem out of balance. When we see populations of lungwort recovering, we know that our air quality is improving and with that, the rainforest. 

How can I help protect temperate rainforest for the future?

Hope is not lost! For one, you are reading this and arming yourself with information to pass onto your family and friends. When you take action on air pollution, you’re benefiting wildlife as well as people’s health – making it doubly important!

We are working hard to combat air pollution in parliament and beyond.

Want to take it a step further?

Join us at the Restore Nature Now march in London on 22nd June, to demand that future leaders prioritise nature and biodiversity. We need immediate political action to bring endangered plants and fungi back from the brink of extinction and restore species-rich habitats, like our temperate rainforest.

Find out more information about the march and how you can get involved here.

Discover more about temperate rainforest

The Rare Lichen that Travelled from Cornwall to Norfolk
Dave Lamacraft translocating Scrambled Egg Lichen in Norfolk

The Rare Lichen that Travelled from Cornwall to Norfolk

An incredible story of returning one of England’s rarest lichens to its historic home – more than 350 miles away.

Plantlife is Calling on the Government to Ban Peat Sales 
A close up of the different types of mosses found on peatlands, taken by Richard Lindsay

Plantlife is Calling on the Government to Ban Peat Sales 

Horticultural businesses, major retailers and NGOs have come together to call on the government to legislate to end peat sales. 

Finding Hazel Gloves Fungus: Why Recording Matters

Finding Hazel Gloves Fungus: Why Recording Matters

Hazel Gloves Fungus is a priority species on the UK Biodiversity Action Plan, learn more about this rainforest fungi this Reverse the Red month.

“Sloping rocky banks and red sandstone cliffs. Extinct.” This is the brief and rather depressing entry for Purple Oxytropis Oxytropis halleri in my old Flora of Angus book (Ingram and Noltie, 1981).

The plant has been gone from Angus for a long time, as it has from North Queensferry and several other locations in Scotland. It’s one of our rarest wildflowers.

Purple oxytropis – a relict

Purple oxytropis is an impressive plant – a member of the Fabaceae (legume) family, with purple flowers, silky leaves and growing in sometimes large colonies in the few places where it does still exist. In the UK, the species is only found in Scotland. Elsewhere, it’s only found in the high mountains of central Europe.

Its Scottish distribution is described as ‘relict’. Most of its remaining populations are coastal, with its stronghold on the north mainland coast. There are a very few populations on the north-east coast, and one extremely isolated population away down on the Mull of Galloway, in the south-west. It’s also found near the summits of three Scottish mountains, two in Perthshire and one in Argyll.

So why is it so rare?

It’s likely that it was never a very common plant, and this country is very much on the northern edge of its range. But there’s no doubt that it was more widely distributed in the past than it is today. Some populations have been lost due to development destroying its habitat. The species is vulnerable to over-grazing– it’s tasty to grazing animals (of which we have an increasing number in Scotland). It also likes open conditions, so won’t thrive in areas that get too encroached with scrub or trees.

Purple oxytropis is dependent on pollinators, mainly bees, to successfully reproduce. Anything impacting on these pollinators will in turn impact on the ability of purple oxytropis to survive.

Its remaining isolated coastal populations are also extremely vulnerable to the impacts of climate change. Rising sea levels could be catastrophic, and associated erosion could spell disaster. The species isn’t widely distributed enough to withstand local impacts like this. A recent study carried out for Plantlife concluded that it is probable that the Mull of Galloway population will become extinct if no new plants appear and highlighted the threat that a single event such as a landslip could have on the fragile population there.

The isolated nature of the remaining populations means that the plants are likely to exhibit low genetic diversity and high levels of inbreeding, which will weaken them and make their future survival less likely. However, We don’t know enough about the genetics of the species to be sure.

Does any of this matter?

How much should we care about trying to save a species which is already on the edge of its range? Surely, it’s doing okay in the Alps? The problem with that argument is simply, where do you draw the line? If we lose it from Scotland, does the next closest population become the ‘edge of range’ one which it’s OK to lose? And then the next?

If we want to live in a country that’s rich in wildlife, we must look after the species that make their home here. The problems facing Purple Oxytropis are difficult but not insurmountable. And by tackling the problems facing this species, we will also address these problems for a host of other species which are facing similar threats.

Looking at a map of Purple Oxytropis distribution over time is like watching a series of lights blinking out one by one. I don’t think anyone wants the map to go completely dark. It’s up to us to keep as many lights on as possible.

Plantlife is taking action for Purple Oxytropis through Species on the Edge partnership.

Look, the seasons, they are a-changing and I don’t know about you, but I am so looking forward to that sweet, sweet spring time weather. After the cold winter days and long winter nights, I am so ready to get out there and breathe in the freshness of spring.

Glen Nant – Scotland Rainforest

I would highly recommend taking a visit to one of Scotland’s rainforests if you have the opportunity. The high rainfall, and mild temperatures result in lush mossy areas just bursting with lichens and bryophytes it really does feel like I’ve stepped into a fairy tale. And if that doesn’t attract your attention then you’ll be impressed with the sheer abundance, diversity, and rarity of the species of Scotland’s rainforest.

It won’t be my first visit to the temperate rainforest; however, I’ve visited Glen Nant in the past. Plantlife has a downloadable handy wild plant walk leaflet for the Glen Nant Important Plant Area (IPA), so it was a solid motivation for a visit for me.

Cuckooflower.

North Berwick Law for a Grassland Hike

But I hear you ask, what if I don’t want to visit a rainforest site? Looking for something short and located in the central belt?

Then download and check out North Berwick Law, our guide is for a nice 1 mile hike up one iconic hill in East Lothian. Plenty of opportunity to spot wild plants too, like Meadow Saxifrage Saxifraga granulata, this snow-white species is found in dry grasslands, or the hilariously named Cuckooflower Cardamine pratensis, due to its delicate purple flowers starting to bloom just as the cuckoo first begins its call.

Dewy Red and orange hairs or trendrils of the sundrew plant

Ben Nevis

If you’re the Munro bagging type, then check out the Ben Nevis IPA, a delightful 10-mile hike that is absolutely rich in Bog Asphodel Narthecium ossifragum a plant once used for its potential as a natural dye or the delightfully carnivorous Round-leaved Sundew Drosera rotundifolia  (image by Michael Scott) which have long red-coloured stalks that are often seen with globules of ‘dew’ hanging from them. These globules are a polysaccharide solution to trap and digest their prey.

Anagach Woods, Cairngorms

If you’re keen to spend a day out in the Cairngorms, take some time to discover Anagach woods IPA. Download your a free guide here. Soak in the wonders of the Caledonian pinewoods, maybe you’ll spot the rare and iconic Twinflower Linnaea borealis? This special plant is a focal point for our Cairngorms Rare Plants Project. You might also find some Wood sorrel Oxalis acetosella, with its clover-shaped leaves (that taste like apples), this springtime bloomer has delicate white flowers with lilac coloured veins.

Mountains, meadows, rainforests, peat bogs, long or short there’s plenty of space for everyone. I’m looking forward to getting out there and stretching my legs, are you?