State of Nature report - RSPB

THE FACTS BEHIND THE HEADLINES
National Red Lists
350
300
Red List birds (not based on IUCN criteria) pre-1994 Red Data Book categories
1994 IUCN criteria 2001 IUCN criteria
250
200
150
100
50
0
Crustaceans
Molluscs
Grasshoppers and crickets
Dragonflies
True bugs
Riverflies
Bees, ants and wasps
Number of species
Beetles
Moths and butterflies
True flies
Spiders
Stoneworts
Lichens
Bryophytes
Flowering plants
Birds
Figure 4
The number of species Red Listed using various assessment methods.
Red Lists attempt to identify species under threat of
extinction. In recent years, most have been produced using
standard criteria defined by the World Conservation Union
(IUCN), but older assessments, often known as “Red Data
Books” were made using less stringent, though broadly
similar approaches. Here we have used numbers of species
Red Listed by either approach (and a separate system used
for the UK’s birds).
Of the 6,225 species with published assessments of threat
using current IUCN Red List criteria, 755 (12%) are thought
to be threatened with extinction in the UK. A further 833
species have been listed in Red Data Books or similar
assessments, and 52 birds are currently Red Listed as
Birds of Conservation Concern.
Of the groups considered, stoneworts have the highest
proportion of threatened species – about one third of species
– although the overall number is modest, as this is a relatively
small group. The highest number of threatened species can
be found within the flowering plants and there are over 200
threatened species each within the flies, beetles and moths
and butterflies.
For flowering plants and bryophytes, we were able to compare
the proportion of threatened species in different habitat types.
For both taxonomic groups it is the habitat richest in species
that contains not just the highest number of threatened species,
but the highest proportion as well. For example, grasslands
and heathlands are very rich in flowering plants and of the
472 species found there, around one in four are threatened.
Steven Falk (Buglife)
Small fleabane
12 STATE OF NATURE 2013