1989
NEW NOVA SCOTIA RECORDS OF THE LONG-TAILED SHREW, SOREX DISPAR, WITH COMMENTS ON THE TAXONOMIC STATUS OF SOREX DISPAR
AND SOREX GASPENS1S Fred W. SCOTT
Natural History Section, Nova Scotia Museum 1747, Summer Street, Halifax (Nova Scotia) B3H 3A6
and
C. G. van ZYLL de JONG
Curator of Mammals, Canadian Museum of Nature P.O. Box 3443, Station D, Ottawa (Ontario) K1 P 6P4
Résumé
En septembre 1986, nous avons capturé quatre spécimens de Sorex dispar Batchelder dans la vallée de Smith Brook, comté de Cumberland, Nouvelle-Écosse. Le nombre total de spé-cimens connus de cette espèce en provenance des Provinces Maritimes est maintenant de sept.
Des mesures crâniennes de S. dispar en provenance du Nouveau-Brunswick et de la Nouvelle-Écosse sont comparées à celles de S. gaspensis Anthony & Goodwin de la Gaspésie et des Maritimes, et à celles de S. dispar du Maine et du New Hampshire, en utilisant des analyses morphométriques multivariées. Les résultats démontrent qu'il n'y a pas de différence significative dans la forme du crâne entre ces deux espèces. La principale discontinuité morphologique est due à une différence de taille. Une comparaison des distances généralisées au sein des taxons et entre les taxons jette un doute sur la validité de la disctinction spécifique de ces deux taxons.
Abstract
In September 1986, we collected four specimens of Sorex dispar Batchelder in the Smith Brook valley, Cumberland County, Nova Scotia, bringing to seven the number of specimens of this species known from the Maritimes. Cranial measurements of S. dispar from Nova Scotia and New Brunswick are compared with those of S. gaspensis Anthony & Goodwin from the Gaspé Peninsula and the Maritimes, and S. dispar from Maine and New Hamsphire, using mul-tivariate morphometric analyses. Results show that there are no significant differences in skull shape between the two species, and that the morphological discontinuity is primarily due to the differences in size. Comparison of within- and between-taxon generalized distances casts doubt on the specific distinctness of the two taxa.
Introduction
Sorex dispar Batchelder 1896 and Sorex gas-pensis Anthony & Goodwin 1924 are closely related and, as far as is known, allopatric Appalachian shrews currently placed in the subge-nus Otisorex De Kay 1842> (Kirkland & Van Deusen, 1979; George, 1988). Kirkland & Van Deusen (1979) demonstrated the existence of a south-north cline of decreasing size in S. dispar.
When extrapolated northwards to the..distributional range of S. gaspensis, this cline predicts shrews Naturaliste can. (Rev. Écol. Syst.), 116: 145-154 (1989)
larger than S. gaspensis. On the basis of univari-ate statistical comparisons and discriminant anal-ysis, Kirkland & Van Deusen (1979) considered that the discontinuity between S. dispar and S.
gaspensis justified their continued recognition as separate species. French and Kirkland (1983) examined 68 specimens of S. gaspensis collected in 1980 at two localities in New Brunswick and con-firmed the earlier conclusion of Kirkland and Van Deusen (1979) that the two taxa were morpholog-ically and specifmorpholog-ically distinct. However, neither of these analyses explicitly stated whether there
146 LE NATURALISTE CANADIEN, VOL. 116, 1989
were differences in shape between the taxa. A dif-ference in shape implies a different epigenetic process, and hence a greater genetic difference, than does a difference in size alone.
In September 1986 we trapped four specimens of S. dispar in Smith Brook valley, Cumberland County, Nova Scotia, 6 km north of the Folly Mountain site where one of us collected the first Nova Scotian S. dispar in 1984 (Scott, 1987) (Fig. 1). Since these five new specimens are from the northeastern extreme of the S. dispar distribu-tional range and are geographically intermediate between the northern New Brunswick and the Cape Breton Island populations of S. gaspensis, they are of considerable taxonomic and zoogeo-graphic interest and their capture prompted our craniometric re-examination of the two species.
Unlike S. dispar, S. gaspensis occupies a com-paratively restricted range, comprising the Gaspé Peninsula, northern New Brunswick, and Cape Breton Island, Nova Scotia, where it was discov-ered at three sites in 1974 (Roscoe & Majka, 1976). Earlier, a single specimen was collected by one of us (FWS) at Kelly's Mountain, Cape Breton Island, in 1971, but it was not recognized as being a S. gaspensis until 1976. The species has subse-quently been trapped at three additional localities on Cape Breton Island (Herman & Scott, 1984;
Scott, unpubl. data).
The purpose of this paper is twofold: to report on the four additional specimens of S. dispar col-lected in 1986 (including habitats and associated mammal species), and to present the results of our morphometric comparison of these new speci-mens with semples of S. dispar and S. gaspensis from other localities in Québec, the Maritimes and New England.
Materials and methods COLLECTING METHODS
Trapping was carried out at nine sites in Smith Brook valley, Cumberland County, Nova Scotia (Fig. 1) for nine nights between 2 and 11 September 1986, with the specific objective of cap-tu ring S. dispar if it was present. Three types of pit-fall traps were used: white plastic 750-mL ice cream containers, plastic pails of 4.55-L capacity, and conical fibreglass traps 40 cm long and 12 cm in diameter at the mouth. Ail the pails and a small portion of the 750-mL containers were set dry, with bedding material and canned dog food; ail the other pitfall traps were partially filled with water.
Snap traps of two types were used: Museum Special and Victor mouse traps, both baited with peanut butter. The only live traps used were large
Sherman folding traps. Sampling effort totaled 3712 trap-nights (TN) (1823 pitfall, 1799 snap, 90 live). The four individuals of S. dispar captured were taken in pitfall traps, one in a large pail trap with bedding material and food (a heavy dew wet-ted the shrew and it died before traps were checked in the morning) and the other three in par-tially water-filled 750-m L containers.
COLLECTING SITES
The trapping sites were in two basic habitat types: an extensive artificial talus created for the railroad crossing of the valley, constructed about 65 years ago, and areas of natural talus on both sides of the valley west of the railroad. The lower third of each artificial talus slope was forested. The forest was predominantiy balsam fir [Ables balsa-mea (L.) Mill.], with some beech (Fa gus grandifolia Ehrh.), white birch (Betula papyrifera Marsh.), red maple (Acer rubrum L.) and yellow birch (Betula alleghaniensis Britton), with an understory of mountain maple (Acer spicatum Lam.), striped maple (A. pensylvanicum L.) and balsam fir. There was a sparse ground cover (10-15%) of Clintonia borealis (Ait.) Raf., Streptopus amplexifolius (L.) DC. and ferns [Osmunda sp. and Dryopteris phe-gopteris (L.) C. Chr.], and an extensive growth of mosses on the rocks and rotting logs. The remain-der of the talus was bare, with occasional forbs (Chrysanthemum leucanthemum L. and Hype-ricum perforatum L.) and young tree saplings [grey
birch (Betula populifolia Marsh.) and white birch].
Rocks were mostly 15 to 40 cm in diameter and had sharp edges, having been blasted from bed-rock to the north of the valley. One individual of S.
dispar was taken in the artificial talus just 1 m above the well-defined edge of the forest on the west side of the railroad.
The natural talus was ail forested but the north side of the valley (where the talus was most exten-sive) was very dry, there being treeless open areas measuring as much as 10 m in diameter, with vir-tually no ground cover vegetation. Dominant tree species were beech and white birch, with occa-sional balsam fir and striped and sugar maples (Acer saccharum Marsh.). The ground cover was very sparse, never more than about 25% even in the most sheltered wooded areas, and dominated by Aralia nudicaulis L. and Aster acuminatus Michx. Polystichum acrostichoides (Michx.) Schott was the only common pteridophyte in the more mesic areas. Captures on these xeric to mesic natural talus sites were few, only 32 animais in 1684 TN (1.9 captures/100 TN).
The natural talus sampled on the south side of the valley was along a small unnamed tributary stream (which we named "Dispar Brook") and supported a very moist mature yellow birch and
Smith Brook trapping sites
SCOTT & van ZYLL de JONG: SOREX DISPAR IN NOVA SCOTIA
200 m
Folly Mt site GO.
GO
147
Folly L.
Figure 1. Location of trapping sites in Smith Brook valley, Cumberland Co., Nova Scotia, where four spec-imens of Sorex dispar were captured in 1986.
sugar maple forest with scattered balsam fir and a sparse understory of sugar maple, yellow birch and some beech (Fig. 2). There was a lush ground cover dominated by Dryopteris spinulosa (O. F.
Muell.) Watt., with some Aster acuminatus, Aralia nudicaulis and Oxalis montana Raf. This vegeta-tion concealed 90-100% of the substrate. The site yielded 73 animais in 1147 TN (6.36 captures/100 TN), including the other three S. dis-par, ail of which were taken within 5 m of the
stream.
MORPHOLOGICAL ANALYSIS
The crania of the four S. dispar that we col-lected were compared to those of S. dispar from New Hampshire (n = 16), Maine (n = 2) and New Brunswick (n = 2), and with those of S. gaspensis from Québec (n = 6), New Brunswick (n = 28) and Nova Scotia (n = 9) (see Appendix fora list of specimens examined). A total of 10 measure-ments, which could be taken on ail skulls, were used in the comparisons. They are:
1) least interorbital width (10W);
2) least width of the maxillary plate, taken par-allel to the alveolar line (MPL);
3) width across M2-M2 (M2M2W);
4) length of the upper unicuspid tooth row (UL);
5) P4-M3 length (LP4M3);
6) width across 11-11 (11I1W);
7) length of the mandible (ML);
8) height of the coronoid process (CH);
9) coronoid process-condyle length (CCL);
10) length of the mandibular tooth row (LP2M3).
Ail measurements are defined in van Zyll de Jong (1980), except for number 2 which is defined above. The measurements were made using a microlength measuring attachment on a Wild stereomicroscope.
The data were subjected to a canonical variates analysis to clarify the interrelationships among
148 LE NATURALISTE CANADIEN. VOL. 116. 1989
Figure 2. Dispar Brook on the south side of Smith Brook valley, Cumberland Co., Nova Scotia, where three of the four specimens of Sorex dispar were captured.
geographic population samples of the two taxa. A ratio diagram was constructed to show the relative sizes and shapes of the crania of each group, using the New England S. dispar (Le., the New Hampshire and Maine samples combined) as a standard. The product-moment correlation coeffi-cient, r, was used as a measure of similarity in shape between each of the geographic popula-tions (Sneath & Sokal, 1973).
Results
Of the four captures of S. dispar reported here, the one trapped on 4 September in the artificial talus was a subadult male (standard measure-ments: 115-54-12 mm, 3.4 g). The three speci-mens from Dispar Brook were captured on 5 and 8 September. Two were subadult males (standard measurements: 120-57-12.5 mm, 3.9 g; and 114-54-12.3 mm, 3.6 g). The third one was an aduit male with testes less than 1 mm in length (123-60.5-13 mm, 4.2 g).
Table I summarizes the total captures for all Smith Brook valley sites, and for the artificial talus and Dispar Brook sites alone.The oniy species observed elsewhere in the valley but not al Dispar Brook were Tamiasciurus hudsonicus and Zapus hudsonius. The Dispar Brook captures comprised 42.4% of total captures, although the trapping effort there was only 30.9% of the total.
MORPHOMETRIC COMPARISONS
Basic statistics for all ten variables are pre-sented in Table II. Results of the canonical variates analysis are presented in a two-dimensional pro-jection showing individual specimens of the geo-graphic samples (Fig. 3) and in a three-dimensional one showing the group centroids connected by a minimum spanning tree giving generalized distances between nearest neigh-bours in canonical variates space (Fig. 4).
The two-dimensional graph (Fig. 3) shows two main groupings, with S. dispar on 'the left, and S.
gaspensis on the right. The S. dispar specimens
SCOTT & van ZYLL de JONG : SOREX DISPAR IN NOVA SCOTIA 149 TABLE I
Summary of total captures for all Smith Brook valley sites, and for the two traplines where S. dispar was captured 1) SMITH BROOK VALLEY SITES
Number of captures'
Species Pitfall traps
(TN = 1823)
Snap traps (TN = 1799)
Live traps (TN = 90)
Total (TN = 3712)
Sorex cinereus Kerr 2 (0.11) 0 (0) 0 (0) 2 (0.05)
S. fumeus Miller 49 (2.69) 6 (0.33) 0 (0) 55 (1.48)
S. dispar Batchelder 4 (0.22) 0 (0) 0 (0) 4 (0.11)
S. palustris Richardson 1 (0.05) 0 (0) 0 (0) 1 (0.03)
Blarina brevicauda (Say) 0 (0) 21 (1.17) 1 (1.11) 22 (0.59)
Tamiasciurus hudsonicus (Erxleben) 0 (0) 1 (0.06) 0 (0) 1 (0.03)
Peromyscus maniculatus (Wagner) 0 (0) 40 (2.22) 3 (3.33) 43 (1.16)
Clethrionomys gapperi (Vigors) 1 (0.05) 21 (1.17) 2 (2.22) 24 (0.65)
Napœozapus insignis (Miller) 0 (0) 20 (1.11) 0 (0) 20 (0.54)
Total 57 (3.13) 109 (6.06) 6 (6.67) 172 (4.63)
2) ARTIFICIAL TALUS
Number of captures'
Species Pitfall traps Snap traps Live traps Total
(TN = 397) (TN = 484) (TN = 0) (TN = 881)
Sorex cinereus Kerr 2 (0.50) 0 (0) 0 (0) 2 (0.23)
S. fumeus Miller 2 (0.50) 0 (0) 0 (0) 2 (0.23)
S. dispar Batchelder 1 (0.25) 0 (0) 0 (0) 1 (0.11)
Blarina brevicauda (Say) 0 (0) 3 (0.62) 0 (0) 3 (0.34)
Peromyscus maniculatus (Wagner) 0 (0) 14 (2.89) 0 (0) 14 (1.59)
Clethrionomys gapperi (Vigors) 0 (0) 3 (0.62) 0 (0) 3 (0.34)
Napœozapus insignis (Miller) 0 (0) 11 (2.27) 0 (0) 11 (1.25)
Zapus hudsonius (Zimmermann) 0(0) 1 (0.21) 0 (0) 1 (0.11)
Total 5 (1.26) 32 (1.26) 0 (0) 37 (4.20)
3) DISPAR BROOK
Number of captures'
Species Pitfall traps Snap traps Live traps Total
(TN = 742) (TN = 315) (TN = 90) (TN = 1147)
Sorex cinereus Kerr 2 (0.27) 0 (0) 0 (0) 2 (0.17)
S. fumeus Miller 28 (3.77) 0 (0) 0 (0) 28 (2.44)
S. dispar Batchelder 3 (0.40) 0 (0) 0 (0) 3 (0.26)
S. palustris Richardson 1 (1.13) 0 (0) 0 (0) 1 (0.09)
Blarina brevicauda (Say) 0 (0) 8 (2.54) 2 (2.22) 10 (0.87)
Peromyscus maniculatus (Wagner) 0 (0) 8 (2.54) 10 (11.11) 18 (1.57)
Clethrionomys gapperi (Vigors) 0 (0) 8 (2.54) 1 (1.11) 9 (0.78)
Napœozapus insignis (Miller) 0 (0) 1 (0.32) 1 (1.11) 2 (0.17)
Total 34 (4.58) 25 (7.94) 14 (15.56) 73 (6.36)
1 The number of captures per 100 trap nights (TN) is given in parentheses.
from New Brunswick and Nova Scotia, although overlapping to some extent with New England S.
dispar, show a shift to the right in canonical space, toward New Brunswick S. gaspensis. The' charac-ter vectors projected onto the graph suggest that
position along the first axis primarily indicates size, with larger forms situated toward the left. Position along the second axis represents shape variation.
New Brunswick and Québec S. gaspensis are similar, as demonstrated by overlapping specimen
TABLE II
Means and standard deviations for ten cranial measurements of Sorex dispar and Sorex gaspensis
Measurements Sorex dispar Sorex gaspensis
N.H.
(n = 18)
Me (n = 2)
N.B.
(n = 2)
H.S.
(n = 4)
N.B.
(n = 28)
Qué.
(n = 6)
N, S.
(n = 9) Least interorbital
width (10W)
3.14 -±- 0.07 3.15 -± 0.11 3.08 ±- 0.12 3.09 =_F. 0.11 2.97 ±- 0.08 2.95 ±-- 0.05 2.93 ± 0.05 Least width of
zygomatic plate (MPL)
0.83 -± 0.09 0.95 ± 0.11 0.79 ± 0.06 0.87 ± 0.03 0.79 ±-- 0.14 0.80 -± 0.06 0.74 ± 0.06 Width across M2-M2 3.80 ±- 0.07 3.81 ±0.01 3.67 ± 0.07 3.73 ± 0.11 3.49 -± 0.09 3.48 -+- 0.05 3.43 -±- 0.03
(M2M2W) Length of unicuspid
tooth row (UL)
2.63 ± 0.06 2.63 -± 0.02 2.58 -± 0.04 2.65 ±- 0.08 2.47 -± 0.05 2.45 -±- 0.05 2.41 ± 0.09 P4-M3 length 3.92 ± 0.06 3.86 -± 0.08 3.87 -± 0.03 3.87 ± 0.04 3.64 -± 0.07 3.63 -± 0.03 3.55 ± 0.04
(LP4M3)
Width across 11-11 1.28±0.02 1.30 ± 0 1.25 ± 0.01 1.27 ± 0.03 1.21 ±0.03 1.22 ±- 0.03 1.14 -± 0.02 (11I1W)
Length of mandible 8.44 -± 0.10 8.43 ± 0.04 8.32 ± 0.04 8.28 r_t 0.10 7.85 -± 0.18 7.77 ±- 0.12 7.67 ± 0.18 (ML)
Height of coronoid process (CH)
2.95 ± 0.08 3.01 ±0.12 2.88 ± 0 2.98 ± 0.02 2.81 ± 0.05 2.76 ± 0.06 2.70 ±- 0.03 Coronoid process
-condyle length (CCL)
2.15 ± 0.09 2.25 ± 0.01 2.12 -± 0.03 2.17 -± 0.03 2.06 ± 0.08 2.00 JI 0.06 1.96 ±- 0.05 Length of mandibular
tooth row (LP2M3)
4.71 ± 0.08 4.68 _± 0.11 4.63 -± 0.04 4.66 ± 0.10 4.41 ± 0.08 4.39 ± 0.05 4.32 ± 0.06
LE NATURALISTE CANADIEN, VOL. 116, 1989
2
— 0 -
d Me
SCOTT & van ZYLL de JONG SOREX DISPAR IN NOVA SCOTIA 151
-5 -3 5
Figure 3. Position of specimens of Sorex dispar from New Hampshire (d N.H.), Maine (d Me.), Nova Scotia (d N.S.) and New Brunswick (d N.B.), and S. gaspensis from Québec (g Qué.), New Brunswick (g N.B.) and Nova Scotia (g N.S.) projected onto the first two canonicat axes. Character vectors indicate the relative magnitude and direc-tion of each character in two-dimensional canonical variate space. The numbers identifying vectors correspond to those of the measurements described under Materials and methods.
distributions and the proximity of their centroids to one another. The S. gaspensis sample from Cape Breton Island differs appreciably from the main-land samples of S. gaspensis in being situated to the right of and above them. The character vectors suggest that the Cape Breton Island population is characterized by smaller size and narrower I1-I1 width.
The morphometric relationships among our samples of the dispar-gaspensis complex are expressed quantitatively in terms of generalized distances between nearest neighbours in canon-ical space in Figure 4. There is general concord-ance between the geographic distconcord-ances separat-ing neighbourseparat-ing populations and their separation in canonical variates space, except for neigh-bouring populations of S. dispar and S. gaspensis from New Brunswick. Québec and New Brunswick S. gaspensis are 1.63 distance (D) units apart, which is concordant with the geographic distance between them. The difference between the posi-tions of the two along axis III is not too important, as that axis represents a small percentage of total variation. The distances separating nearest geo-graphical neighbours within the two taxa are gen-erally of a similar order of magnitude, except for the within-taxon distance between S. gaspensis from Cape Breton Island and New Brunswick, which closely approaches the between-taxon
dis-tance separating the New Brunswick S. dispar and S. gaspensis from each other.
In our comparison we have included only sam-ples of S. dispar from the northern portion of its geographic range. The overall clinal variation in S.
dispar is thus not displayed and one may get the impression that variation within S. dispar is exceeded greatly by the variation between it and S. gaspensis. Examination of the canonical plots in Kirkland & Van Deusen (1979) and French &
Kirkland (1983) shows that this is not the case. The generalized distance between the samples from the southern and northern extremes of the range of S. dispar is equivalent to that between New England S. dispar and S. gaspensis. ln other words, the New England S. dispar are morphome-trically intermediate between S. gaspensis and the southernmost populations of S. dispar.
A ratio diagram of the 10 measured variables (Fig. 5) shows the differences in size and shape of the crania. The New Brunswick and Nova Scotia specimens of S. dispar were combined in this dia-gram because of the small sample size. The points for the S. gaspensis samples are all situated to the left of the line representing S. dispar from New England (New Hampshire and Maine combined), indicating the smaller dimensions of the former.
Assessment of differences among means with the
152
I I
LE NATURALISTE CANADIEN, VOL. 116, 1989
d N.S.
4 d Me.
d N.B.
se ---
a-- __ g N.B;: • ' ,' 6',.,
...
le
g Que.N.S
III
-6 -4 -2 o 2 4
Figure 4. The centroids of the geographical samples of Sorex dispar and S. gaspensis projected onto the first three canonical axes (sample abbreviations as in Fig. 3). The minimum spanning tree, giving generalized dis-tances between neighbours, summarizes the morphometric relationships between the populations.
-0.06 -0.05 -0.04 -0.03 -0.02 -0.01
10W-MPL -
M2M2W -
UL-LP4M3 -
1111W -
ML
-CH -
CCL-Lp2m3 -
O S. gaspensis- N.S.
o S. gaspensis- Que.
* S. gaspensis - N.B.
* S• dispar- N.S.& N.B.
• S. dispar -N.H. & Me
0 0.01
Figure 5. Ratio diagram comparing ten cranial dimensions (abbreviations as in Materials and methods) in Sorex dispar from the Maritimes and three geographic populations of S. gaspensis with S. dispar from New England, which serves as the standard. Nonsignificant differences are underlined.
Student-Newman-Keuls multiple range test (Sokal
& Rohlf, 1981) indicates that all differences are sig-nificant at the 5% level except for the width of the maxillary plate (MPL); in that measurement, Québec and New Brunswick S. gaspensis are not significantly different from the two S. dispar sam-ples (Fig. 5). In S. dispar from the Maritime Provinces, seven of ten cranial dimensions are smaller than those of New England S. dispar, only three of them significantly so (M2M2W, LP4M3 and 1111W).
Within S. gaspensis, the samples from Québec and New Brunswick differ significantly from one another in only one measurement (CH), whereas the Cape Breton Island sample differs from the Québec sample in two (LP4M3, 1111W), and from the New Brunswick sample in eight (LP4M3, 1111W, M2M2W, UL, ML, CH, CCL and LP2M3).
As far as relative size is concerned, the ratio diagram shows a situation similar to that portrayed in Figures 3 and 4, with Cape Breton Island S. gas-pensis being the smallest, followed by S. gaspen-sis from Québec and New Brunswick, S. dispar from Nova Scotia and New Brunswick, and finally S. dispar from New England. Similarity in shape based on the same ten variables is generally high and reveals a pattern of interlocality variation incongruent with the existence of two distinct cies (Table Ill). If two morphologically distinct spe-cies were present, one would expect the similarity coefficient to form two distinct clusters correspond-ing to S. gaspensis and S. dispar populations
SCOTT & van ZYLL de JONG : SOREX DISPAR IN NOVA SCOTIA 153 TABLE III
Similarities in shape (r) between each of the geographical samples of S. dispar and S. gaspensis New England S. dispar 1.0000
Maritimes S. dispar 0.9717 1.0000
Nova Scotia S. gaspensis 0.5256 0.7114 1.0000
New Brunswick S. gaspensis 0.9826 0.9986 0.6738 1.0000
Québec S. gaspensis 0.9948 0.9430 0.4372 0.9590 1.0000
respectively. The most dissimilar with respect to shape is the Cape Breton Island population of S.
gaspensis, with its highest similarity to Maritimes S. dispar (r = 0.711) and its lowest to S. gaspen-sis from Québec (r = 0.437). The highest value (r = 0.998), curiously, is that between New Brunswick S. gaspensis and S. dispar from the Maritimes.
Discussion
The two Smith Brook valley sites at which S.
dispar was captured are similar to the Folly Mountain site (Scott, 1987) in all essential respects. The main differences are that the Folly Mountain site is more than 300 m from running water and the talus is not continuous. It faces east and is slightly drier than Dispar Brook (though much wetter than the driest Smith Brook valley sites), and the forest contains a higher proportion of beech. Ground cover plants cover only about 30% of the substrate. The six S. gaspensis sites in Cape Breton Island with which we are familiar are all essentially similar to the Folly Mountain and
dispar was captured are similar to the Folly Mountain site (Scott, 1987) in all essential respects. The main differences are that the Folly Mountain site is more than 300 m from running water and the talus is not continuous. It faces east and is slightly drier than Dispar Brook (though much wetter than the driest Smith Brook valley sites), and the forest contains a higher proportion of beech. Ground cover plants cover only about 30% of the substrate. The six S. gaspensis sites in Cape Breton Island with which we are familiar are all essentially similar to the Folly Mountain and