. The Canadian field-naturalist. 76 The Canadian Field-Naturalist Vol. 95 BARRHEAD WESTLOCK •20 .K. • 27 • 25 •26 • 48 wP (24A) •^ • 32 • S •30 CAMROSE »21 • R WETASKIWIN 10 km (23A) 53 114 113 Figure 1. Locations where litter samples (numbers) and handpicked samples (letters) were taken in central Alberta. See Appendix 1 for descriptions of exact locations. dae) among the handpicked samples. In all, 18 species have been identified (Table 2). Three zonitids {Euconulus fulvus, Retinella elec- trina, Vitrina alaskana), one endodontid {Discus cronkhitei), one pupillid {Vertigo gouldi), and the Ta
. The Canadian field-naturalist. 76 The Canadian Field-Naturalist Vol. 95 BARRHEAD WESTLOCK •20 .K. • 27 • 25 •26 • 48 wP (24A) •^ • 32 • S •30 CAMROSE »21 • R WETASKIWIN 10 km (23A) 53 114 113 Figure 1. Locations where litter samples (numbers) and handpicked samples (letters) were taken in central Alberta. See Appendix 1 for descriptions of exact locations. dae) among the handpicked samples. In all, 18 species have been identified (Table 2). Three zonitids {Euconulus fulvus, Retinella elec- trina, Vitrina alaskana), one endodontid {Discus cronkhitei), one pupillid {Vertigo gouldi), and the Table 1—Relative numbers and sizes of terrestrial molluscs recovered in 19 handpicked and 31 litter samples Mean number of individuals Size of molluscs (no. dimensions >2 mm) Handpicked samples Litter samples 0 1 2 only cionellid {Cionella lubrica) were widely distrib- uted throughout the area and in the various forest types. Each species was present in at least 90% of the samples (Table 2). Discus cronkhitei and Vertigo gouldi were also relatively abundant at each site, aver- aging about 50 m- sample of forest litter (Table 2). Vitrina alaskana and Cionella lubrica, although widespread, were found at much lower den- sities, on average about 12 m- (Table 2). These differences may represent absolute differen- ces in abundance or differences in rates of disappear- ance of the shells of the respective species. In most samples, some shells were eroded and often on the point of disintegration, the snails presumably having been dead for some time. Thus abundance figures include some shells of snails that may have been dead. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ottawa Field-Naturalists' Club. Ottawa, Ottawa Field-Natu
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