Senecio jacobaea - part three

Apologies for the delay, but as suggested on the last post - here is the third post.

Common Ragwort (Senecio jacobaea) in its first year stage creates an immature ragwort plant that resembles a small rosette of between 5 and 15 centimetres across with no flowers. In the second year, it pushes forth a green stem that can reach up and over 1.5 metres high (I know the blasted plants are higher than I am) with the yellow flowers at the top. The photo below shows a recently extricated plant. 

The third photo of this blog (see below) will show the scale of the plant, however it is possible to see how the plant in its second year develops most of its energy budget to create the huge stem with frond-like leaves.

The root is considerably small compared to the length of the stem. You don't have to imagine these plants as sails as you can see them from late July along the sides of single and dual carriageways - the shallow roots help the stem tot sway but not snap. This plant's anatomy reminds me of the huge trees in the tropical rainforests as they also have tall trunks and relatively short roots. This may be due to the fact that both plants exploit poor soils to create huge plants to increase the chance of their progeny surviving; Senecio jacobaea is a natural plant of semi-natural grasslands and colonise well drained and sandy soils. The plant can be an indicator of where sandy soils exist in a field. The small root is also useful in the plant's downfall, the ragwort fork has small tines, and when inserted at the bast of the plant, can act as a pivot for felling the large stem.

Senecio jacobaea has other tricks in its biological arsenal. The flower heads and vegetative parts of Senecio jacobaea have an allelopathic effect on the surrounding vegetation by suppressing the competition from other plants - so that the Common Ragwort can colonise an area. This can be seen by the creation of stands or swathes of Common Ragwort. As seen in the photograph below, the ragwork fork is shown for scale.

With various studies, it has seen that the seeds can travel from the parent plant of under a metre to over five metres. A plant can hold from 4,760 to 174,230 of seeds per plant. After flowering, the plant dies relying on the seeds to increase the invasion and the potential seed bank. The seed bank, the soil below the plant, can be affected by animals, failed germination, fire, mechanical, pathogens, physiological death, predation, rainfall dispersal, above ground and sub-soil water flow and wind.

Yes, it can be said that Senecio jacobaea or Common Ragwort can reduce the quality of a pasture through allelopathy and the decomposition of the leaf litter; it has the potential to kill many agricultural and pastoral animals; and finally it has a crucial part in providing a suitable food source and habitat for many invertebrates...as the Defra document states "It should be expected that some common ragwort will continue to occur in such swards and will fulfill its role in the ecological dynamics of well-drained grassland ecosystems."

If anyone is interested, please either email or add a comment, I can provide sources of the reports quoted in the blog entry above.

Senecio jacobaea - part two

On the last post, I said that Common Ragwort (Senecio jacobaea) "can be dangerous to livestock" and yes it can be if not properly managed. However, as also stated in the first post of this series, I did write that the plant supported both the caterpillar and the moths stages of the Cinnabar moth (Tyria jacobaea) as well as a host of invertebrates.

A recently published web page by The Wildlife Trust of South and West Wales notes that Common Ragwort has "done really well this summer" due to the inconsistent weather of this year and the flowers, leaves and plants have acted as an invaluable source for "at least thirty species of invertebrate". These include one form of aphid, 12 fly species, 7 leaf beetle species, 1 macro moth, 7 micro moths, 1 form of mite and 1 type of thrip. The article states that other invertebrates use it as a nectar source, especially if other flowers haven't survived as well, and these include 2 bee species, various butterflies, Conopid flies, hoverflies, at least 40 species of Noctuid moths, a minimum of 30 species of solitary bees and a minimum of 18 solitary wasp species. (Please note, that some of these details are repeated from the last post).

The reason for the larger than normal image is so that you will be able to see the bee, the beetle and the butterfly, any ideas on what they might be?

It is tiresome and back-breaking work, once in a while you get a wonderful view - I have been accompanied by some kestrels and possibly a buzzard. If you look at the photograph below, you may even seen one of the avian accompanists to my ragworticidal acivities.

Unfortunately the camera on a phone is not the most ideal at trying to take long distance shots of hovering kestrels. I will say that as I left last night, I looked back to see that my work hadn't disturbed the birds. I saw one, two and then to the left another pair - there were four kestrels hovering across the length of the field, if any more had turned up I would have thought that they may have been auditioning for Alfred Hitchcock's film "The Birds'.

The above photograph isn't a complete waste of time - it shows a loose stand of Common Ragwort. Next time, I will explain more about the stands tomorrow. I bet you can't wait?

Senecio jacobaea - part one

Today, yesterday and tomorrow as well as a few other days I will be roguing - the act of identifying and removing undesired plants from agricultural fields (the definition taken from Wikipedia) - ragwort plants.

Common Ragwort (Senecio jacobaea) is native to the United Kingdom and despite being of importance to the native invertebrate's habitat, it can be dangerous to livestock.

The plant contains a form of alkaloid toxin (pyrrolizidine) that may act as a poison to agricultural livestock including avian, bovine, cervidae, equine, and swine members. This inability to safely consume and digest this toxin by these herbivores can lead to problems if the plant is combined with hay, haylage or silage.

The plant also provides a site for the egg laying as well as the food supply for the plant's main consumer - the Cinnabar moth (Tyria jacobaeae) - and the flowers support the insects who drink the nectar, especially in times when other crop flowers are scarce. These include 2 bee species, butterflies, Conopid, flies, hoverflies, a minimum of 40 Noctuid moths, a minimum of 30 species of solitary bees, and a minimum of 18 species of solitary wasps.

More tomorrow, have you any questions?