Does Hedera helix cause damage?

Kingdom: Plantae

Family: Araliaceae

Species: Hedera helix

Hedera helix is an evergreen, common species of ivy in the UK, and is widely spread across Europe. It is often seen climbing buildings or trees, which it does by using specialised hairs called aerial roots which cling to the surfaces. Hedera helix prefers non-reflective, darker, rough surfaces with a fairly neutral pH of around 6.5.

Leaves - Dark, glossy green pale veins.

Flowers – Yellowish green, appear in clusters called umbels.

Fruit – Purple-black to orange-yellow, present in mature plants, which ripen in late winter.

The flowers are very rich in nectar and act as a valuable food course for bees and other insects in late autumn when food is scarce, before many of the insects go into hibernation (such as wasps – the queen wasp constructs a golf ball-sized hibernation cell which needs to be in a sheltered place until late spring). Over 70 species of insects are attracted to the flowers. The ivy covering also provides shelter for insects, birds, bats and other small mammals. The ivy also attracts a very rare species, the golden hoverfly. The best chance of seeing one of these is by going to ancient ivy-covered trees. Some mature plants also produce berries, which are a nutritious food source for birds, although slightly poisonous to humans (cause severe discomfort). Also, at least 16 species of birds eat the berries that grow on the ivy.

Although it is often heard that ivy damages trees, and that the weight of it can make them fall over, this very rarely actually happens and it should not be removed. It is not a parasitic plant and has a separate root system in the soil where it absorbs its own nutrients, and its presence provides huge wildlife benefits. However, as Hedera helix can conceal defects or issues in the trees, sometimes it may need to be removed to allow assessment of the tree’s health. It may also need to be removed to conserve other plants such as lichens which grow on ancient trees.

As for growing on buildings, this is also not damaging – it is often used in Europe for its ability to cool the interior during summer and provide insulation during winter, and the protection it provides for the building during extreme weather. However, in other countries such as the United States it is classed as invasive and can choke other plants, and should be eradicated where it is found in countries such as the US, New Zealand, and Australia.

So in conclusion, Hedera helix is not damaging and its growth on the UEA grounds is a good sign as it increases the level of biodiversity on campus by providing shelter and a food source to many different species of birds and insects.

 

Field Trip - Winterton-On-Sea - Trampling and Biodiversity

Last Friday, we visited Winterton-on-Sea, and completed a transect from the beach to approximately 300m inland. We used a quadrat to record a variety of aspects measuring the biodiversity, including the number of species in each quadrat at each site.

When we moved forward to the sample point, Jemima (my partner in the investigation) would just throw the quadrat randomly to avoid biased placing of the quadrat. We then counted the number of species in the quadrat – this was rushed as we had very limited time so was not very accurate and we had to try and count them and then make an educated guess. This is not the most accurate way of measuring but it allowed us to gather enough data to make suggestions about the diversity of the habitat.

The graph shows a rapid initial increase, then a fairly random distribution of data. The initial increase was possibly due to there being more nutrients in the soil as we moved inland, and the conditions became less harsh as it was more sheltered from the shoreline conditions. It is sheltered by the concrete wall that is built along the coast – this is now covered in land so is not visible, rather, it just looks like a small hill. The soil on top of the concrete wall would have a different salinity level and so this may have affected the number of species present and may explain the decrease between sample points 13 and 17. If we had more time, we could have possibly recorded height of sample point above sea level, which is very difficult to measure accurately, and impossibly with the time constraints we had. We could have also measured the pH of the soil and looked at the effect this had, as the pH does decrease further inland. If these constraints weren’t in place I would also identify all the species that are present as then the number of species recorded is a more accurate measurement, rather than just make an estimate. 

Also, to gather a bigger sample size, I would do several transects, possibly three about 15 m apart to get a better idea of the diversity of the whole area. Although we did several transects amongst us as a group and this allowed us to discuss the findings, due to differences in sampling strategies there was great differences in the data. Also, there is the question of which measure of diversity is the best, as it may not be possible to record all in a proper investigation. It is questionable if number of species is the best measurement of species diversity, some may argue that percentage of bare land is a better measure.

We then collected a small amount of data which shows how the number of lichens changes with distance from footpath, to investigate the effect of humans trampling in the dune system. There were many factors to consider when doing this, such as:

• How far away from the path should we measure?
• Should we measure the same distance from the path each time, or do we alter the distance in comparison to width of path? Does this assume people walk off the path more if the path is wider?
• How do you class where the path ends? If using the level of trampling, is a trampling index needed? Do you need to measure the height of the vegetation each time to classify the level of trampling?
• How many paths do you need to measure to get a good sample size?
• Do you need to measure the percentage coverage in each square in the quadrat, to get an idea of how the lichen cover changes over an area or is just using the whole quadrat good enough? But then does this miss out all this information of how the lichen cover gradually changes?

Clearly, it is very difficult to take all these factors into consideration, especially with no prior planning. Although we did not get very much data on lichen coverage due to the fact that we were thinking about all these factors for so long, we did see a difference in the lichen being present off path, whereas on the paths there was none. To conserve this, you could have fewer defined paths, with small barriers either side of the path, or even just pieces of wood to indicate where the paths are, to put people off going off the paths and disturbing the vegetation away from the paths. As lichens are very easily disturbed, this would help increase lichen coverage. You could also have fences to prevent people going on certain areas completely, particularly areas that have been trampled on excessively, and allow them to recover as succession occurs. Information boards could also be placed on these pathways to educate people about why the dune systems need to be conserved, and to highlight the importance of limiting the effect that recreation activities have on the area. 

False Chanterelles

Kingdom: Fungi

Family: Hygrophoropsidaceae

Species: Hygrophoropsis aurantiaca

This is the False Chanterelle mushroom, known as Hygrophoropsis aurantiaca. It is given its name because the fungus resembles the edible Chanterelle. The False Chanterelle is fairly common in Britain and the UK, and while it is not poisonous, it has been known to give some people hallucinations and others have reported digestive problems. It is not particularly tasty either, described as being earthy and bitter, so is not classed as edible. They are in season from August – November. The ones I found have slightly wavy, lobed caps due to age.

It’s distinctive features include:

Cap - 2 to 8 cm across. Usually a convex shape and an orange colour, although the ones I found are going slightly brown as they are going out of season. This was the feature that most helped me to identify the species as it is the most distinctive.

Gills – A slightly brighter colour orange than the cap. Gills are used by mushrooms as a means of spore dispersal. These gills are decurrent (extend down the stem) and narrow. I used this feature to double check that I had correctly identified the species after I had examined the cap.

Stem – Small – 3 – 5 cm in height and 5 – 10 mm in diameter. Grows paler toward the base.

How is it different from the real Chanterelle?

The main way to tell the difference is by examining the gills. In real Chanterelles, the gills appear to be lumpy folds rather than close blades. This is because the real Chanterelle has false gills while the false Chanterelle has real gills. The False Chanterelle’s cap is also often a deeper orange and are not one uniform colour, rather, they are graded. The real Chanterelle is a more yellowy colour.

Stinging Nettles

Kingdom: Plantae

Family: Urticaceae

Species: Urtica dioica

While I was walking around UEA’s lake earlier this week trying to get inspiration for my first blog post, I stung my arm on a stinging nettle – something I am sure has happened to pretty much everyone who has ever set foot in the countryside. While looking for a dock leaf to get rid of the stinging, I realised I didn’t actually know if dock leaves worked, and thought that actually investigating stinging nettles a little bit seemed to be a good start for my first post.

Stinging nettles (Urtica dioica L.) sting you with tiny hollow hairs (the silica tips break off when they come into contact with something) on their leaves. They pierce the skin and inject a venom mixture of histamine, acetylcholine and serotonin (even the ‘happy hormone’ can cause you pain – when injected by stinging nettles, it becomes an irritant) which cause pain and inflammation, while tartaric and oxalic acid can extend the pain. However, dock leaves actually have no impact and the reasoning for using them is often backed up by false science used to increase their validity. Some people suggest it is because their sap is alkaline so neutralises the acid, but it’s actually acidic so this is not true. Some also claim they contain a natural antihistamine, but this is also false. Using actual antihistamine cream is much more likely to help, as it can block the receptors that histamine normally binds to and prevent it causing pain.

So at this point in my research I was still annoyed about my sting but then began reading about why nettles are actually a benefit to UK wildlife. The stinging nettle supports over 40 species of insects, including small tortoiseshell and peacock butterflies, and the nettle leaves form a protective shield against grazing animals which are potential predators to these small insects. The aphids living on them are sometimes eaten by blue tits and other woodland birds that dart around the stems. Nettles are also a magnet for other insect-eaters like hedgehogs, shrews, frogs and toads, at all times of year, so can greatly benefit biodiversity of an area. Therefore, while nettles are weeds and not threatened, they are often encouraged to grow by nature conservationists. This has led to charities running campaigns to get people to dedicate a patch of their garden to be left untouched to grow as it would in the wild, so plants such as nettles can grow and lead to a higher level of biodiversity in the small part of the garden – something which could be important as the population continues to grow and urban settlements expand, as mowing the lawn on a regular basis makes it very hard for many species to be able to live there. 

Nettles can also be used for humans’ purposes – they can be eaten as a vegetable, as cooking destroys the stings, for recipes such as nettle soup. Nettles are actually a good source of calcium, magnesium and iron among other trace elements and vitamins. Mature leaves can actually be used in production of cheese, cosmetics and dyeing fabric! They can also be used to make a tonic which can be used as a remedy for rheumatism (a disease causing inflammation in muscles and joints) as the nettle stings actually have anti-inflammatory properties which inhibit the inflammatory response, despite causing one itself!

So despite it hurting a bit when it stings you, nettles are a big contributor to enhancing biodiversity in an area and can be used for loads of purposes for humans too.