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Maculinea as
bioindicators |
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The Maculinea exhibit a very low
tolerance to environmental change while displaying highly specific
ecological requirements (Wynhoff, 2001). Between them, the five species
are key representatives of several of the most valued and endangered types
of grassland biotope in Europe, ranging from calcareous to acid soils and
from very wet to very dry hydrologies. |
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Maculinea arion
©Josef
Settele
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M. schencki
©Jeremy Thomas

Neotypus sp.
©Holger
Loritz

wet grassland, fen
©Sarah Gwillym |
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Theory and some empirical studies suggest that of all the
European butterflies, the five species of Maculinea and the
specific food plants, Myrmica ants and parasitoids with which they
interact could be excellent indicators of biodiversity levels across the
wide variety of grassland types that they collectively inhabit, because
they possess two additional attributes (Elmes & Thomas 1992): (i) Each
species is globally endangered. The rare grasslands that support >1
Maculinea species and their parasitoids may represent the ultimate in
biodiversity attainable in that particular ecosystem. In fact, crude
inventories suggest that the spectrum of sites from the few that support
full Maculinea systems down to the many with just a few common ants
is correlated with a similar gradient in high to low biodiversity levels
in many other taxa. (ii) This is no chance association. A strong
functional link exists between Maculinea butterflies and their
inconspicuous host ants which, as dominant keystone species, greatly
influence which communities of other organisms can inhabit their sites.
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Theory suggests that Maculinea systems could be the best indicators
among butterflies, for four reasons:
- Although rare, Maculinea species are highly visible and
better recorded than many other rarities, so a good database of their
distribution already exists.
- The five Maculinea species encompass most valued
grassland biotopes, ranging from wet to dry, lowland to montane,
calcareous to acid.
- Each potential Maculinea system encompasses a range of
grasslands supporting a hierarchy of diversity from sites with
Myrmica ants alone (common), to Myrmica + foodplants
(frequent), to Maculinea (rare), to Maculinea + parasitoid
(very rare), and finally to >1 Maculinea spp. + parasitoids
(extremely rare).
- As specialists at the pinnacle of the food chain among insects, the
Maculinea and their parasitoids have more exacting (sensitive)
requirements than other butterflies and parasitoids.
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