The effects of climate on abundance depend on local environments. A predicted interaction was
tested in the land snail Theba pisana, in contrasting habitats of dense Acacia thickets and adjacent
areas of low open vegetation, in introduced populations in Western Australia. The snails aestivate on
vegetation over summer and mortality is higher in the Open habitat than in the Acacia. Growth
experiments in winter showed that this advantage of the Acacia habitat in summer is countered by
more rapid growth and higher survival of juvenile snails in the Open habitat