Flies
43 species of fly have become extinct in England in the last 200 years, 10 of which are shown below
Species: Belida angelicae
Extinct: 1936
Species: Clitellaria ephippium
Extinct: 1850
© John Reinecke
© Hectonichus
WELSH GROUNDSEL
Senecio cambrensis
A unique, endemic species currently found only in north Wales and nowhere else in the world.
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Rarity: Recorded historically from 28 sites. Currently known from 5 sites, which collectively supported 156 plants in 2024
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Cause of decline: Drought, lack of management, competition, herbicide use
Background
Welsh Groundsel is a newly evolved species that arose within the last 100 years following allopolyploid hybridization between two related species, Groundsel (Senecio vulgaris) and Oxford Ragwort (Senecio squalidus). It is one of the classic examples of rapid evolution of a new species.
It was first discovered in 1925 growing at Brynteg near Wrexham, but wasn’t recognized as a new species until 1948 when it was also discovered at Cefn-y-bedd (Flintshire). It was officially described as a new species in 1955.
Since then, it has been found at 35 locations, all of which are in north Wales. The only exception has been an appearance at Leith Docks, Edinburgh, from 1973 to 1993. The Welsh sites have mainly been around Chirk & Ruabon, in the Wrexham area, and from Mochdre to Llanddulas on the north Wales coast.
Although some of these sites once supported thousands of plants, almost all of them have not been recorded recently and many have now gone.
Ecology and Conservation
Welsh Groundsel is a ruderal annual, occupying open sites with disturbed substrates that are free from competition, especially perennials. It is most commonly found on roadsides, pavement edges and along gutters, beside walls and fences, and along the bottom of hedgerows. It also occurs in gravel and discarded rubble, through pavement cracks, and occasionally in walls and even as a weed in gardens next to roads.
The vegetation community in which it grows is also typically ruderal. Interestingly, S. cambrensis seems to occupy transient microsites within patches of ruderal vegetation, where small open areas are maintained by disturbance but are lost after a few years as perennial competitors take over.
For this reason, maintenance of the metapopulation across a site depends on repeated, often stochastic disturbance to provide a mosaic of new microsites for occupation. Occasionally, larger-scale disturbance allows very large populations to form, sometimes with many hundreds or even thousands of plants.
Germination tends to occur in flushes when conditions are favourable from spring through to autumn. Autumn-germinating plants can overwinter and flower as early as April. The main flush of flowering is in May-June, usually with another flush in September, although plants can be in flower any time from May to October. The main constraint on growth and flowering is drought, which can severely impact populations and result in the death of all individuals.
Our work
Given the lack of recent site survey and anecdotal concerns that populations were declining and some sites had been lost, we undertook a survey of a small sample of sites in June 2024. Seven sites with relatively recent records were targeted, and of these, five sites were found to support plants. No plants were found at three other sites (Mochdre, Ewloe and New Brighton).
Over the next few years, we will continue to monitor the known populations, as well as visit the remaining sites to build up a complete picture of this species' distribution and scarcity. We will work with landowners to bring habitats into favourable condition & re-establish historic sites through reintroduction.