Welsh Lichen Red List - Lichens of Wales
Welsh Lichen Red List - Lichens of Wales
Welsh Lichen Red List - Lichens of Wales
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available to colonize <strong>Wales</strong>. Those few species that might fall into this category also tend<br />
to occur on man-made substrates in <strong>Wales</strong> such as memorials in churchyards or even to<br />
fall into a category well-understood within higher plants but as yet not developed to<br />
encompass lichens – that <strong>of</strong> a species <strong>of</strong> casual occurrence. The thinking still needs to be<br />
developed to prioritize our actions with respect to these species, for which <strong>Wales</strong> may<br />
never have been part <strong>of</strong> their natural range.<br />
Threatened <strong>Welsh</strong> taxon with<br />
population close to English<br />
population and taxon has a high<br />
dynamism score<br />
Immigration over entire <strong>Welsh</strong><br />
range likely?<br />
Yes<br />
Threatened in GB or endemic or<br />
near endemic?<br />
No<br />
Downgrade <strong>Welsh</strong> status category<br />
by one level<br />
No / unknown<br />
Figure 1. Chart used to determine whether any changes to the <strong>Welsh</strong> threat category<br />
were necessary due to potential immigration from England (adapted from IUCN, 2003)<br />
Yes<br />
5.3 IUCN categories in <strong>Wales</strong><br />
Apart from the modifications given in sections 5.1 and 5.2 above, the standard IUCN<br />
categories and criteria (IUCN, 2001) have been used to produce this <strong>Red</strong> Data <strong>List</strong>. This<br />
means that the same thresholds used to determine categories in the British <strong>Red</strong> Data <strong>List</strong><br />
have been used for <strong>Wales</strong>, and the lists are therefore directly comparable. Because <strong>of</strong> this,<br />
a detailed treatment <strong>of</strong> how each criterion was applied is not reproduced here, but readers<br />
are referred to Woods and Coppins (2003) and its subsequent editions for further<br />
information. The following, however, gives a brief summary <strong>of</strong> the categories and criteria<br />
used here.<br />
EXTINCT (EX)<br />
A taxon is presumed extinct when surveys in known and/or expected habitat throughout<br />
its historic range have failed to record an individual. For this evaluation, a period <strong>of</strong> 50<br />
years is generally used, providing there have been reasonable attempts to re-discover the<br />
species concerned.<br />
Rhestr o Gen Data Coch ar gyfer Cymru<br />
No change to status category<br />
No change to status category<br />
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