What makes something native?

In conservation and biology in general there is a lot of talk over whether a species is native. This can often be quite a divisive issue because when species are not native they can often be removed or not be a part of policy making. This then means that when conservation plans are put into place a decision must be made as to whether a species is native or not.

So how do you decide whether something is in fact native?

A seemingly easy way of doing this is whether a species has been living in a location for a long time. However due to the wonderful nature of the world trying to pick a starting point in time and figure out what was living there can be a tricky task. For example certain plant species have always been in the UK such as Oak trees. They are therefore classed as native. Other plant species have been brought into the UK. This can happen for lots of different reasons whether its because the plant has a medical property that humans can use or it could be that they are just pretty. Many of these species have a specific few years when they were brought in. One example of this is Rhododendron ponticum which was brought in as an ornamental plant from Spain in 1763. Its since become an invasive species and out competes a lot of native species and such its regarded as a non-native species. However some research suggests that this species was growing in the UK before the last ice age. Obviously this was a long time ago but this does then pose the question of is it a native species as it once was many years a go.

It is a complicated question that I couldn’t answer in a simple blog post. However, most native species are defined as species that originated in their location naturally and without the involvement of human activity or intervention. This definition works for the majority of cases but should be called into question every once in a while!

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The Poisons Collection: Beware of the Honey!

Today we’re putting not just one plant in the poisons collection but a genus! This genus being rhododendron. Not all but many of the species in this genus are poisonous (Robertson, 2014). So why should you beware of honey well keep reading and you will find out!

Sherlock_holmes_ver5Rhododendron are an invasive species to the UK. The particular species that causes the majority of the problem is Rhododendron ponticum. Brought over as an ornamental plant they have now spread to woodland areas replacing the natural under story (Taylor et al., 2013).

You may have heard of rhododendron from the Sherlock series. In the 2009 film it was mentioned as a proposed way to arrange a fake execution and in the BBC series it was speculated as being part of Sherlock’s fake death scheme (Skellet, 2009). It is also mentioned in Joyce’s Ulysses.

All parts of the plant contain a cocktail of toxins including andromedotoxin, grayanotoxin, rhodotoxin and acetylandromedol and the nectar is believed to have the highest concentrationRhododendron-ponticum (Robertson, 2014). However most cases of humans becoming ill not through directly ingesting the plant but through eating honey made by bees feeding off rhododendron. This honey is nicknamed “mad honey” and can even cause hallucinations (Bryce, 2014). Often its actually animals grazing on the plant. It does have the capability to kill animals or cause them to have extreme symptoms such as slow heart rate and exhaustion. Death comes from respiratory failure but this only occurs when enough foliage has been consumed (Robertson, 2014).

To conclude Rhododendrons are a beautiful yet invasive plant and one definitely to be wary and watchful of!


Bryce, E.. (2004). The Strange History of ‘Mad Honey’. Avaliable: http://modernfarmer.com/2014/09/strange-history-hallucinogenic-mad-honey/. Last accessed: 16/11/15

Robertson, J.. (2014). Rhododendron. Available:http://www.thepoisongarden.co.uk/atoz/rhododendron.htm. Last accessed 16/11/15

Skellett, C.. (2009). Rhododendron Poison – Truth behind the science of Sherlock Holmes. Available: http://aschoonerofscience.com/poisons/rhododendron-poison-truth-behind-the-science-of-sherlock-holmes/. Last accessed 16/11/15

Taylor, S. L., Hill, R.A. and Edwards, C.. (2013). Characterising invasive non-native Rhododendron ponticum spectra signatures with spectroradiometry in the laboratory and field: Potential for remote mapping. ISPRS Journal of Photogrammetry and Remote Sensing. 81 (1), 70-81.

ThatBiologist Everywhere!