Geoscience Reference
In-Depth Information
worms and other large invertebrates are sparse so that a large network is needed to
harvest enough food.
F
IG. 40
Occurrence of moles in 652 pastures from districts in Yorkshire with distinctive soils. 1, Fen peat, Vale of
Pickering (40 pastures); 2, Light sandy soil, Vale of Pickering (38); 3, Alluvium, Vale of York (29); 4,
Heavy clays, Rydale and Vale of Pickering (52); 5, Soils overlying magnesian limestones and marls, Don-
caster area (15); 6, Heavy clays over Jurassic sandstones, North East Yorkshire (222); 7, Chalk Wolds
(69); 8, Millstone grit soils, South and West Yorkshire (87); 9, Clay/warp soils subject to seasonal flood-
ing, between Rivers Went and Don, Doncaster (74); 10, 'Improved' moorland soils on southern edge of
North Yorkshire Moors (74); (Data from C. A. Howes.)
The distribution and population density of moles depend on several factors, for
example, food availability, disturbance and soil compaction. Mellanby described the
occurrence of moles in different habitats such as farmland, deciduous and coniferous
woodland, Fenland and Breckland. In this last habitat, he mentions the relatively low
population occurring where 'an immense amount of surface activity gives the erro-
neous impression that moles abound'. Mole signs are sometimes an indication more
of activity than density.
By concentrating on farmland alone, C.A.Howes has looked specifically at the
importance of soil type on mole frequency. He did this by recording molesigns dur-
ing journeys in Yorkshire and Humberside which passed exclusively through areas
