Slug numbers, biomass and respiratory metabolism in a beech woodland - Wytham Woods, Oxford.

Four species of slug occurred on the site but a single species, Arion hortensis Férussac, dominated in terms of numbers, biomass and respiratory metabolism. This species was found to have two main generations per year, a finding which contrasts with the annual life-cycle described for arable situations in NE England. A majority of slugs was found in areas with deep leaf litter and ground vegetation. Mean annual population density was 34 m-2 while mean biomass equalled 266 mg d.wt.m-2. Respiratory metabolism was calculated to be in a range equivalent to 18.101-29.686 kJ m-2 yr-1. The most probable figure for annual food consumption was estimated at 3 to 4 g d.wt. m-2 yr-1 i.e. 1.28 to 1.70% of ground litter disappearance yr-1. The P/B ratio was 3.1 and net population production efficiency 36.4%.