Conservation Biology of Lycaenidae (Butterflies) - IUCN

Wet meadows and grasslands are azonal, like screes, in the
sense that they can develop almost at any altitude where
appropriate soil conditions are met (in this case a high humidity).
Particularly at low elevations they are among the most
endangered habitats in Europe. Species living on these grasslands
are threatened throughout their range and examples of these are
some of the most endangered species of Maculinea: M. alcon
(Denis and Schiffermüller); M. teleius (Bergsträsser); and M.
nausithous (Bergsträsser). Threats to this type of habitat are
often related to land drainage and include changes in land
management as a consequence of the very productive nature of
these grasslands.
Shrublands
Shrublands normally grow as a consequence of the action of
disturbing ecological factors such as strong winds, short
vegetation times, human management or recurrent fires. They
are interesting because some rare species are almost restricted
to these formations.
True heathlands dominated by Erica species are the habitat of
Plebejus argus, a species that has declined rapidly in England
but which does not seem to have similar conservation problems
in other countries.
Mediterranean shrublands (garigues or chaparral formations)
also support interesting rare species such as Iolana iolas, a
circum-Mediterranean species living on chaparral. Another
peculiar type of Mediterranean shrubland is represented by
heathlands (with Erica arborea and E. scoparia) found on the
highest, windswept elevations of Corsica, Sardinia and Elba
(France and Italy, Balletto et al. 1989). This is the exclusive
habitat of the endemic Lycaeides Corsica (Tutt).
Kretania psylorita (Freyer) is a rare endemic living in
Cretan shrublands dominated by an Astragalus species (Leigheb
et al. 1990). Similar to these are some species living on biotopes
dominated by Thymus species (called locally in Spain
'tomillares') where some endemics (Cupido lorquinii Herrich-
Schaeffer) or rare species (Pseudophilotes bavius, P.
abencerragus (Pierret) and Scolitantides orion (Pallas)) live.
Subalpine-type shrublands are found on mountains above the
tree line. They are characterised by the presence of
Rhododendron and Vaccinium, often in association with dwarf
pine trees. Their butterflies are mainly boreal-alpine elements
which include, in wet areas, Aricia nicias Meigen, and Vacciniina
optilete (Knoch) among the lycaenids.
Wetlands
These are probably the most endangered among European
habitats as a consequence of drainage either to control mosquitoes
or to transform the habitat into agricultural land (particularly
rice fields). Wetland drainage has affected huge areas, both in
central Europe (see Kudrna 1986 for the case of Bohemia in the
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16th century) and in the south of the continent (Italy in the 19th
century). Typical lycaenids living on wetlands are Lycaena
dispar (Haworth), L. helle (Denis and Schiffermüller) and at
higher altitudes or latitudes, Vaciniina optilete. These three
species are listed as threatened by Heath (1981) and L. dispar
is listed in the Berne Convention as being one of the most
endangered European lycaenids.
Causes of decline and extinction of
European lycaenids
This subject has been considered by several authors when
dealing with the broader topics of European butterflies (Heath
1981, Thomas 1984b, Kudrna 1986) and insects of the
Mediterranean Basin (Balletto and Casale 1991). A considerable
amount of information and a number of opinions are also
available for individual countries (Blab and Kudrna 1982;
Viedma 1984; Balletto and Kudrna 1985; SBN 1987; Gonseth
1987; Swaay 1990; Bàlint 1991; Kulfan and Kulfan 1991).
Although no single review has dealt with the subject solely with
reference to lycaenids, many papers pointing out causes of
decline of individual species are now available (see Table 1 for
references). An overview of the topic is provided in Table 4,
where information on butterfly conservation at a European
level is summarised.
Habitat alteration or destruction
All three authors referred to in Table 4, as well as various
national reports, identify this factor as the most important one
for butterfly decline throughout Europe. A change in habitat
quality is the cause of all extinctions documented to have taken
place. This applies also to the lycaenids Lycaena dispar and
Maculinea arion in the United Kingdom (Duffey 1968; Thomas
1980) and Lycaena hippothoe (L.), M. arion, M. nausithous and
M. teleius in The Netherlands (Heath 1981).
Some examples of documented extinctions in Europe are
given in Table 5. Wetland and grassland destruction or alteration
are the main causes of recent extinctions.
Butterfly declines are reaching an alarming scale in most
central and north European countries where a high proportion
of the fauna is experiencing dramatic range reductions (Heath
et al. 1984). The range reductions of the following lycaenid
species have been caused by habitat changes: Plebejus argus
(United Kingdom, Ravenscroft 1990); Polyommatus bellargus
(United Kingdom, Thomas 1983); Satyrium pruni (United
Kingdom, Thomas 1974);LycaenadisparandL.helle(Germany,
Kudrna 1986); and Polyommatus exuberans Verity and L.
dispar (Italy, Balletto et al. 1982a–e, Balletto in press).
Habitat alterations can be quite subtle: for example, a slight
change of growth in grass height on British Maculinea arion
sites is enough to make the habitat unsuitable for the butterfly
host ant (Thomas 1989). This change produced by grazing
relaxation was sufficient to cause the disappearance of the