Conservation of Britain’s biodiversity: Distribution and status of the Welsh endemic Hieracium breconicola, Beacons Hawkweed (Asteraceae)

Hieracium breconicola P.D. Sell, Beacons Hawkweed, is a Welsh endemic plant confined to the Brecon Beacons. Field surveys 2009-2020 indicate only one plant survives in one of its three sites. The IUCN threat status is ‘Critically Endangered’; unless conservation action is undertaken soon, this species will soon be extinct in the wild.


Introduction
Hieracium breconicola P. D. Sell, Beacons Hawkweed, is a very rare Welsh endemic (Moore, 2009;McCosh & Rich, 2018). It was first described as a new species by Sell & Murrell (2006) from plants named incorrectly as H. scoticum F. Hanb. or H. gothicum auct. var. latifolium Backh. (Ley 1909). It is a member of Hieracium section Oreadea (Fr.) Dahlst. It is characterised by the few basal leaves and 2-5 stem leaves which are dark green with rigid hairs on the margins, the few-flowered inflorescence, the dark green, obtuse involucral bracts with numerous simple hairs, few glandular hairs and few or no stellate hairs, and the yellow styles (Figs. 1-3). Sell & Murrell (2006) cited H. breconicola from the cliffs of Fan Nedd and Llyn y Fan Fawr in Breconshire (v.c.42). An additional site was subsequently reported from Llyn y Fan Fach in Carmarthenshire (v.c.44) with a note that possible plants had been found in 2009 at Fan Nedd (Moore, 2009;McCosh & Rich, 2011   Field surveys were carried out in 2009 by S. Lee (née Moore) and updated by T.
Rich in 2020. The 'look-see' method (Hill et al. 2005) was adopted for field data collection as it was the most appropriate to survey the sites which had many inaccessible areas on cliffs, thus the number of plants is a minimum. Each site was searched as far as practicable, and the location of the plants recorded using GPS. Soil pH was measured with a calibrated pHep2 Hanna pocket-sized pH meter in a 50:50 mixture of soil with distilled water.

Results
The historical records indicate H. breconicola occurs in three sites in two vice-counties ( Fig. 4), and these were used to direct the field surveys. This site was also surveyed on the same days in 2009 as Llyn y Fan Fawr (cf. above) and again no H. breconicola was found. Historically this is a very rich Hieracium site with 22 species recorded from it, but only six species have been recorded recently. Grazing by sheep may have eliminated it here along with many other species, but it could still occur on inaccessible rocks which we could not search safely.
The two plants confirmed at Fan Nedd in 2010 had declined to one last plant by 2020, and it is in imminent danger of extinction. It may always have been rare; Ley (1909) indicated it (as 'H. scoticum') was rare in Brecon and although he usually collected many Hieracium duplicates he did not do so with H. breconicola, perhaps indicating even in his time it was present only in small quantity. A short video showing the last plant is available on YouTube (Rich, 2020).
Like its relatives, H. breconicola is likely to be a polycarpic and apomictic but this has not been tested experimentally. One of the two plants has been known for at least 11 years, indicating that they may be relatively long-lived. It typically flowers in July and August. Seed set appears to be low and eight visits were undertaken before ripe seed was collected. As the only population occurs on relatively inaccessible cliffs, grazing must restrict it to steep areas out of the reach of sheep. A conservation action plan is urgently required to ensure survival of this species in the wild. This should include a significant reduction in sheep grazing levels at Fan Nedd, and a reintroduction programme to increase the population. The site is not protected or designated in any way other than being located within the Brecon Beacons National Park which confers no practical protection for such a species. Seed was collected in 2013, from which plants were gown by C. Gait and seed sent to the Millennium Seed Bank for ex situ conservation.