Realm: Terrestrial
Climate: Temperate
Biome: Temperate broadleaf and mixed forests
Central latitude: 53.403160
Central longitude: -0.829650
Duration: 3 years, from 1999 to 2001

543 records

16 distinct species

Across the time series Deroceras reticulatum is the most frequently occurring species

Methods

These observations were made in Beckingham, in north Nottinghamshire, UK, 53° 24? 11.37? N 0° 49? 46.74? W in a village garden. All observations made by Chris du Feu. Two Draza slug monitoring mats (produced and supplied by Bayer) were placed near each other in a shaded grassy part of the garden and remained in the same small area (no more than 2m x 2m) throughout These plastic mats were 45cm square with a reflective grey upper surface and a black lower surface. Between the surfaces was some insulating and moisture absorbent material. Species nomenclature is according to FSC Field Guide to Slugs of Britain and Ireland, Rowson et al. ISBN 978-1-908819-13-0. Original designations have been amended where appropriate (e.g. Deroceras invadens was recorded originally as Deroceras panormitanum. Note that Arion (Arion) agg. is likely to include both Arion (Arion) rufus and Arion (Arion) ater. Arion (Carinarion) circumscriptus includes records of both circumscriptus and silvaticus subspecies treated as one because most individuals have appearance which is not clearly one or the other. Limacus sp. could be either Limacus maculatus, Limacus flavus or hybrids between the two species. The observations were made at a time when Limacus maculatus was stealthily replacing Limacus flavus in the area. Zero counts are given as blank cells. No species not listed were recorded during the period of the observations although some other species had been recorded occasionally in the garden. These were Arion (Kobeltia) hortensis, Arion (Kobeltia) intermedius, Ambigolimax valentianus, Milax gagates and Tandonia sowerbyi. There are two consecutive time series In both cases Inspections were made approximately weekly always by day, and slugs of all species present were counted. The mats were always in the same shady part of the garden In the first two years, 1999 & 2000, one mat (Fixed) was always replaced exactly in the same place after inspections. The second mat (Moveable) was replaced in a different position. For this mat, a 3x3 grid was defined and in the first week the mat was placed in the centre square. In subsequent weeks it was placed in another of these 9 grid squares. In this way the second mat always remained roughly in the same position but the vegetation below it was able to recover between weeks when the mat was laid on it. (The aim of this was to assess whether the vegetation-free, dry earth below objects which have been in place for a long time was more, or less, attractive to slugs than fresher vegetation. I was surprised that it seems not so but now wonder whether the mat moving process did deter slugs more than dry, vegetation-free earth below the fixed mat.) In the third year, mats were replaced in the same place after each inspection. For Mat 1, slugs roosting attached to the lower surface and those roosting on the soil below were counted separately. For Mat 2 all slugs were counted, irrespective of roosting position but, after counting all specimens of the pestilential Budapest Slug Tandonia budapestensis were removed and destroyed. The counts were stopped after about a year when the mats disintegrated. The aim of this was to see any preferences in roosting positions and also to assess the effect of removing individuals of the most pestilential species. [Chris du Feu, 2020] Additional: this study corresponds to the first of two consecutive time series when slugs were monitored with a fixed and a moveable mat. The last period of the dataset, when both mats were fixed, corresponds to the study: Slug Numbers Beckingham 1999 2002 (series 2001-2002)

Citation(s)