Pressley p h (1 Ergebnisse)

Monadenia (Monadenia) setosa occurs mainly in riparian corridors with dense deciduous understory in Trinity County, California, U.S.A. Eastward, Monadenia (Shastelix) churchi, which within the range of M. setosa is restricted to open hillside habitats, occupies streamside habitats. On the north and west, M. setosa is replaced by Monadenia (Monadenia) fidelis, with a narrow zone of intergradation. One population, with a density of 0.11 snail/m2, was monitored over an annual cycle. Capture of marked individuals departed significantly from randomness. Widely varying population estimates reflected irregular snail activity patterns. Reproductive maturity apparently occurs at different seasons of the year; early growth is probably rapid, slowing as maturity is approached. Feeding occurs on the ground and on the trunks of trees with smooth bark. Both adults and juveniles occur on the ground and also climb vertical surfaces. Beetle and possible rodent predation occur; the latter may often be unsuccessful. Limited home ranges, probably related to available shelter, may exist. Monadenia (Monadenia) callipeplus of the Scott River drainage represents a parallel development of a bristly shell surface. Monadenia (Monadenia) scottiana is elevated from a subspecies of M. fidelis to species rank. Monadenia chaceana is restored to species rank and assigned to the subgenus Monadenia s.s. 14 pp., 8 figs, 4.…