kf 7 - NERC Open Research Archive - Natural Environment Research

THREATS
Sorre are n driy colo- al and 3lthough a rev. :felon es may
conta n ng thousands of hats :rev may represent Ire ent. re gree.ri ng s-fick
covering rhousanas of km- For example a qr-noloprfas ferfameLT, nun,
colony :n Aales totalling aeout 400 :DEC'S occupies an annua! area of
2500 km- iSfeboings' data) Thus, catas:rophes to breed nd colorces .Anere
almost all adult females congregate can remove oafs from w de areas
instantly Trss applies equally to colonies n natural s,tes, eg caves and
hollow trees, and man-made sites, eg buldings ano mines Gatastrohnes can
be accidental, eg flooding or collapse of caves ane mines, trees plowing
down or burning down of buildings, killing by vandals and collectors; out
almost certainly of greater significance today is remerial timber treatment n
buildings This latter practice has been increasing since 1950 and is probaOlv
the most important factor killing bats and reducing breeding success in
Bntain, the estimated number of dwellings treated annually rose from
Plate 1 Greater horseshoe bat nursery colony. A very large P1500 bats)
colony was killed with the insecticide dieldrin The pile of
droppings was 49 cm deep
8