home flora of romania endangered species of transylvania endangered habitats of transylvania
Centaurea simonkaiana Hayek
|
This taxon is not present, as many Romanian naturalists can learn from the available literature in quite many locations from Arad, Timis and Bihor counties (Zarand Mountains and Zarand Corridor along Crisul Alb river). In fact, all the locations except two belong to the mesophitic thermonemoral species Centaurea stenolepis A. Kern which was considered as 'Centaurea simonkaiana Hayek var. fusca Prodan et Nyar. ' This taxon has nothing to do with the true mesoxeric-xeric local endemic Centaurea simonkaiana and creates a dangerous relaxation in concerning the conservation status of the species. In fact, this later species is very much restricted to its 'locco classico' - the andesitic cliffs from Iosasel and Gurahont villages above the Crisul Alb river (see the images below). Sadly, on the cliffs from Iosasel the species seems to get extinct so it remains as a quite small and relic population only on Baltele Hill's abrupts. The species is very sensitive to sheep overgrazing which is intensive in the area. The so called 'natural reservation' declared in the area of Baltele Hill for the preservation of this species is non functional and really exists only in some official papers.As a conclusion, we consider this very local endemic as one of the most threatened species from the flora of Romania nowadays. The resemblance between Centaurea simonkaiana Hayek and Centaurea trichocephala Bieberstein is clear but however their ecology seems to be very different. The second species is a ruderal antropohile invader while our narrow endemic is a threatened species which cannot withstand any degree of ruderalization and overgrazing. Centaurea trichocephala Bieberstein can be seen here in some photographs made in Russia and Ukraine. Baltele Hill from near Gurahont and Iosasel villages, andesitic rocks and cliffs above Crisul Alb river, Arad county, 5th of September 2010. dr. Alexandru Badarau, alexandru@transsilvanica.net
Below it can be seen the single illustration / iconography of the typical Centaurea trichocephala M. Bieb ex Willd. from the forest-steppe of European Russia (and Moldavia?) available on the internet. The page was extracted from a manual of invasive weeds for North America (Roche, C.T,, Roche B.F. (2001) - Identification of Knapweeds and Starthistles in the Pacific Northwest, A Pacific Northwest Extension Publication, Washington, Oregon, Idaho, pag. 14). The plant is considered a quarantine weed in USA which should be erradicated anywhere it is met on its territory. Thus we can see that the typical species can act as an invasive ruderal, a fact inconceivable for our very local endemic Centaurea simonkaiana. Also the fastigiate general shape of the plant is not compatible with our plant from Gurahont, Arad county. There are two hypotheses: 1. The plant is truly a Pannonian counterpart / vicariant of the Pontic Centaurea trichocephala as there are many other biogeographic examples to be found. 2. The similarities are just conjectural and in fact simonkaiana and trichocephala are not directly related. It can happen that simonkaiana derived from a local founder isolated population of Centaurea stenolepis for which the local ecological conditions have dramatically changed at a time, from mesic forestry to xeric and rocky, forcing the initial population to evolve rapidly. The general shape of simonkaiana seems to be much like that of stenolepis than that of trichocephala. Of course, the answer to this biogeographical dilemma will be delivered only through mollecular analysis which are expected to be done as soon as possible in the future. As a personal point of view we support the second theory.
New photographs some of a good quality with Centaurea trichocephala Bieberstein can pe seen here. |
