THE DISTRIBUTION AND DECLINE OF BRITISH BUMBLE BEES (BOMBUS LATR.)
PAUL H. WILLIAMS
The suggested recent decrease in the distributional ranges of certain species of bumble bees was investigated in the data collected by the Bumblebee Distribution Maps Scheme, using a numerical classificatory approach. Three major biogeographic elements and four biogeographic regions are defined, and changes in their composition and distribution described. Large reductions in the distributional ranges recorded after 1960 were found for two of the biogeographic elements (especially for the Southern Local Species: Bombus sublerraneus (L.), B. sylvarum (L.), B. ruderatus (F.) and B. humilis Ill.), which have resulted in the emergence of a new Central Impoverished Region covering 23 vice-counties in Central England.