2008 NORTHEASTERN NATURALIST 15(4):497–514 Use of Residual Forest by Snowshoe Hare in a Clear-cut Boreal Landscape Martin-Hugues St-Laurent1,*, Marianne Cusson1, Jean Ferron1, and Alain Caron1 Abstract - The short-term negative impacts on Lepus americanus (Snowshoe Hare) of logging activities in boreal forest are widely recognized, and conservation efforts are being taken now in designing residual forest stands to maintain use of logged landscapes by hares. This study evaluated the effectiveness of three types of residual stands in maintaining hares during the high phase of hare density cycle in Picea mariana (Black Spruce) forest of eastern Canada. Residual forest stands sampled were upland strips (60 m wide, 250–950 m long, mesic conditions), riparian strips (100 m wide, 250–950 m long, along a permanent stream), and residual blocks (200–300 m wide, 20–50 ha). Control stands were undisturbed forest. All stands were considered mature (56–97 years old). Pellet and browse surveys were conducted during spring 1998 and 1999. Hare abundance indices were significantly lower (1999), or tended to be lower (1998), in strips than in blocks, although habitat composition and structure of the treatments did not differ from control stands. Pellet presence was positively related to vertical cover. In 1998, foraging activity (browsing) was significantly higher in control and block landscapes than in strip landscapes; browsing was positively related to availability of ericaceous and deciduous twigs. In 1998, twenty Snowshoe Hares were radio-tracked in residual stands to monitor their summer home ranges, fidelity to capture sites and to type of residual stand, use of clear-cuts and uncut forest, and daily movements. There was a clear trend towards lower fidelity to strips than to blocks, and summer home ranges and daily movements (>330 m) tended to be larger in strips compared to those in blocks. Our study suggests that up to 5 years after logging, residual forest blocks appeared to be more suitable habitat in summer for Snowshoe Hare than were 60-m-wide strips. Introduction Forest harvesting is known to be the major source of disturbance in the boreal forest (McRae et al. 2001). Consequently, several studies and review papers have documented the effects of logging and fragmentation on wildlife (Betts et al. 2006, Potvin et al. 1999, St-Laurent et al. 2007, Thompson 1988). According to the coarse-filter approach (Hunter et al. 1988), preserving the optimal habitat of major prey species can insure the maintenance of a predator guild higher in the food chain. In the boreal forest, Lepus americanus Erxleben (Snowshoe Hare) is considered a keystone species due to its significant impact both on vegetation and predators (Krebs et al. 2001a, Murray 2003). Although several studies have documented the 1Département de Biologie, Chimie, et Géographie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, QC, Canada, G5L 3A1. *Corresponding author - martin-hugues_st-laurent@uqar.ca. 498 Northeastern Naturalist Vol. 15, No. 4 effects of large-scale commercial clear-cutting on hares (e.g., Conroy et al. 1979; Ferron et al. 1998; Monthey 1986; Potvin et al. 2005a, b), little attention has been paid to Snowshoe Hare response to residual forest configurations following logging (Darveau et al. 1998, St-Laurent et al. 2007). Recent studies conducted in the Picea mariana Mill. (Black Spruce) forest of Abitibi-Témiscamingue (Québec, Canada) revealed that hares do not recolonize clear-cuts prior to 4 years after logging (Ferron et al. 1998), and that pre-logging densities were only half recovered after ten years (Potvin et al. 2005a). Indeed, Snowshoe Hares rarely used regenerating stands in boreal forests before 8–10 years following clear-cut logging (de Bellefeuille et al. 2001, Thompson 1988). Although young successional stages are known to be preferred by Snowshoe Hare (St-Laurent et al. 2008), residual forest stands (i.e., stands of mature forest remaining in the landscape) with dense understory are essential to maintain hare populations in a landscape after logging (Potvin et al. 1999). As cover density is a major habitat component for hares (Brocke 1975, Ferron and Ouellet 1992, Murray 2003), they will concentrate their activities in residual forest and leave logged landscapes shortly after clear-cutting. For hares, undisturbed and residual mature forests may facilitate landscape recolonization after logging (Ferron et al. 1998), and minimize the short-term negative effects of logging by maintaining source populations in the landscape (Potvin and Bertrand 2004). Among eastern Canadian provinces, current logging regulations generate a great diversity of shapes and sizes of residual forest configurations (see McRae et al. 2001). However, few studies have documented Snowshoe Hare use of residual forest stands in comparison to mature continuous forest. Linear forest strips and island-like blocks are two common residual forest stands found in logged landscapes (Potvin and Courtois 2007). These types of residual forest stands differ by their mean size and width (strips < blocks) and their edge-to-area ratio (strips > blocks). Both residual blocks and strips are authorized currently on public lands in Québec to limit the size of clearcut patches (Québec Government 1996). Strips can be 60 or 100 m wide, depending on the size of adjacent clear-cuts. Strips are either riparian (along a permanent stream) or upland (mesic conditions) and are linked to larger undisturbed mature forest (see Fig. 1a in Ferron and St-Laurent 2005). In contrast, residual blocks between 20 and 50 ha were authorized as an experimental treatment at the beginning of this study. Darveau et al. (1998) studied riparian strip use by hares in Abies balsamea Mill. (Balsam Fir) forest and found that all riparian strips, ranging in width between 20 to 300 m, supported comparable low hare densities. In winter, Potvin et al. (2005b) demonstrated that hares avoided strip edges and were more common in wider strips (>100 m). Surprisingly, the effectiveness of upland strips and residual blocks in maintaining Snowshoe Hare in a logged landscape has not been tested. The objective of this study was to evaluate the effectiveness of riparian strips, upland strips, and residual blocks in maintaining use of logged landscapes by hares in boreal Black Spruce forest. We hypothesized that re2008 M.-H. St-Laurent, M. Cusson, J. Ferron, and A. Caron 499 sidual block configuration would be more suitable to Snowshoe Hares than smaller residual forest stands (riparian and upland strips). Residual blocks have less edge and offer more interior forest, thus providing a better refuge for hares. This hypothesis is based on the observations of Potvin et al. (2005b) that forest clear-cut edges are avoided by Snowshoe Hares in winter. Field Site Description This study was conducted in the Black Spruce-moss boreal forest northwest of Lake St. Jean, central Québec, Canada (49°09'N, 72°57'W). The study area was located at the northern limit of the Balsam Fir-Betula papyrifera Marsh. (White Birch) ecological region (Thibault 1985). The annual mean air temperature ranged between -2.5 and 0 °C, while the total annual precipitation varied between 90 and 110 cm, a third of which fell as snow (Environment Canada 1993). The area had a mean elevation of 330 m. At the time of data collection (1998–1999), about 40% of the 60- km2 study area had been clear-cut since 1994 using the CPRS technique (cutting with protection of regeneration and soils), a modified clear-cutting technique requiring that harvesting and skidding trails be equally spaced by 10–15 m (Potvin et al. 2005b). Among remaining forest, 32% was distributed as residual forest stands (i.e., upland strips, riparian strips, or residual blocks). Mature Black Spruce stands (90 years old) dominated over the landscape, but Pinus banksiana Lamb. (Jack Pine), Balsam Fir, Larix laricina Koch (Tamarack), White Birch, and Populus tremuloides Michx. (Trembling Aspen) were also present in the area. The understory was composed of primarily Kalmia angustifolia Linnaeus (Sheep Laurel) and Ledum groenlandicum Oeder (Labrador Tea), with Alnus spp. (alders) along streams. Eighteen sites were randomly selected within the study area, and included 5 upland strips, 5 riparian strips, 3 residual blocks and 5 controls. Sites were all crown land dominated by mature Black Spruce forest (mean stand age = 89 ± 23 years, ranging from 56 to 97 years old) that was not previously harvested. Upland and riparian strips were approximately 60–100 m wide and varied in area from 1.7 to 6.9 ha. They also varied in length from 250 to 960 m and were all connected to contiguous forest. Residual blocks were portions of forest from 18.2 to 49.7 ha, ranging in width from 200 to 300 m. Control sites ranged between 22.2 and 46.4 ha and were located in larger patches of continuous mature forest, distanced by at least 500 m to the closest clear-cut edge to limit possible edge effects (St-Laurent et al. 2007). All sites were >1 km apart to avoid pseudoreplication. At the beginning of the experiment, study sites had been isolated for 1–3 years post-clear-cutting and their use by hares was monitored in 1998 and 1999. Concerning Snowshoe Hare populations on a regional scale, our study area was considered to be representative of a much larger area (20,000 km2) (Potvin et al. 2005b) within the spruce-moss ecological region (Thibault 1985). In the Lake St. Jean region, Snowshoe Hare is known to exhibit a density cycle (Godbout 1998), with a periodicity of ≈10 years but of lower 500 Northeastern Naturalist Vol. 15, No. 4 amplitude than in northwestern Canada (Ferron and St-Laurent 2008). Data collection was conducted during the high phase of this cycle (1998–1999). Methods We compared hare use of riparian strips, upland strips, and residual blocks to continuous mature forest (as a control) using pellet counts and browse surveys, and radio-tracking data for home ranges, daily movements, and fidelity to capture sites, 1 to 5 years after logging. Pellet and browse surveys To evaluate relative use of the different residual forest stand types by Snowshoe Hare, pellet and browse surveys were conducted (as abundance indices) during spring 1998 and 1999 at all the studied stands. Dependent on stand size and type, 15–24 plots/site were distributed on 3–7 parallel survey lines. Survey lines were 50 m apart in residual blocks and controls and 100 m apart in strips. Each plot was a 1-m radius (3.14-m2) circle identified with a permanent stake in the center (St-Laurent et al. 2007, 2008). We used 1-m radius circular plots rather than rectangular plots or small circular plots (0.155 m2) to increase likelihood of recording fecal pellets for low hare densities (Murray et al. 2002). Fecal pellets were counted and removed shortly after snow-melt before the onset of green-up (Ferron et al. 1998; Krebs et al. 1987, 2001b). We excluded the first year of pellet counts (1997) because it may have included some pellets older than 1 year (Murray et al. 2005). Although pellet decomposition rate influences the precision of pellet counts (Murray et al. 2005), we did not correct our estimates because the annual degradation rate of hare fecal pellets is relatively low (approximately 8%) near our study area (M.-H. St-Laurent, unpubl. data). Pellet abundances were transformed to presence/absence to conduct statistical analyses. Moreover, pellet counts were conducted on a 1-year interval basis; such a short and regular interval is considered to minimize bias related to pellet decomposition (Murray et al. 2005). A browse survey was conducted yearly in spring 1998 and 1999 on the same 1-m radius plots. All stems >1 cm diameter at breast height (DBH) and all twigs (the last terminal or lateral division of a stem, >10 cm long [Hosie 1972, Potvin 1995]) <2 m above ground, were identified to species, counted, and used to establish the relative availability of each species (Potvin 1995). Browsing was transformed to presence/absence data. Differentiation of browsing between hare and ungulates was done using the aspect of cut twigs (sharply cut = hares, shredded = ungulates; Potvin 1995). The relative availability, use by hares. and importance (in %) of each species in the hare diet were calculated (following Potvin’s [1995] methods). Lateral and vertical vegetation covers were evaluated on each plot as indices of anti-predatory cover for hares. Lateral cover (foliage density estimated in five density classes, from low obstruction [10%] to almost complete obstruction by vegetation [90%]) of the understory was measured with a 2-m 2008 M.-H. St-Laurent, M. Cusson, J. Ferron, and A. Caron 501 vegetation profile board (Nudds 1977) placed at two points 15 m distant from the center of the plot, and perpendicular to the survey line. Vertical cover density (canopy closure) was measured at the center of each plot through a 50-cm square frame held at arm’s length above the head (Benz 2000; St- Laurent et al. 2007, 2008), using the same density classes as for lateral cover. Although foliage was primarily coniferous, both lateral and vertical covers were measured before green-up to represent hiding cover during the majority of the year. Telemetry In 1998, 20 hares were radio-tracked (Holohil System, model MI-2 with mortality sensor) from mid-May to mid-August to monitor home ranges, fidelity to capture site (i.e., proportion of locations in the study site where captured), fidelity to the type of residual stand where captured (i.e., proportion of locations in the same type of residual stand as capture site: upland strip, riparian strip, or residual block), use of clear-cuts and surrounding uncut forest (except residual stands), and daily movements. In mixed forest stands, Brocke (1975) reported that only 5% of Snowshoe Hare daily movements were >330 m. We analysed daily movements >330 m and hypothesized that hares in poorer habitats (such as a Black Spruce stand) or in small residual forest fragments (such as a forest strip) would have a higherproportion of daily movements beyond 330 m than would have in a better habitat and/or a larger residual forest stand. All animals were located 5 times per week by homing technique, where we approached at close range (<10 m) until the strength or direction of the signal indicated that the animal had just moved, or by direct observation of the animal (White and Garrott 1990). Each location was georeferenced with a global positioning system (GPS). Locations were distributed evenly between dawn and dusk to encompass resting and activity periods (Ferron and Ouellet 1992). Eight animals died from predation; as sample size was limited, no survival analyses were done. Data analyses Due to very low hare density in our study area (Appendix 1), we used presence/absence of fecal pellets and browsing as indices of habitat use by hare. Using presence/absence data to determine occupancy rate rather than absolute abundance can limit ambiguous interpretation and may lead to more conservative conclusions about habitat use (MacKenzie 2005) through proportion of sites used by a given species (Zielinski and Stauffer 1996). This is especially true when mean abundances are very low, and high values in some plots can mask the absence of pellets (or browsing) (Stanley and Royle 2005). This approach was used to study other aspects of hare reactions to managed landscapes in the boreal forest of eastern Canada (St-Laurent et al. 2007, 2008). We constructed a logistic regression model (Hosmer and Lemeshow 1989) to relate the presence of fecal pellets with treatments (upland strips, riparian strips, residual blocks, and control), years (1998 and 1999), their interaction, and four habitat covariates measured at the plot 502 Northeastern Naturalist Vol. 15, No. 4 scale: vertical cover, lateral cover, percentage of deciduous twigs, and ericaceous twigs. Another logistic regression model was built using the presence of browsing as a dependent variable. No variable selection was conducted; complete models were estimated using the GENMOD and the GLIMMIX procedures in SAS 9.1 statistical software (SAS Institute, Inc. 2004). For all spatial analyses, only two treatments were considered: strips (upland and riparian pooled) and residual blocks. Home-range size was calculated with the fixed kernel method (FK 95%) (Seaman and Powell 1996) using the “Animal Movement Program” extension (Hooge and Eichenlaub 1997) to ArcView 3.2a (ESRI 1997). For each individual, we also calculated the number of locations for each of the following categories: capture site, type of residual stand where caught (strip or block), and use of clearcuts and uncut forest (excluding residual stands). This approach allowed us to determine use of clear-cuts and uncut forest, and fidelity to capture site and to a given type of residual stand. For analysis of daily movements, pairs of consecutive locations for a given animal that were recorded within 48 hr were retained (n = 461 pairs from 20 hares). Straight-line distance between successive locations was compared using a standardized time elapse period of 24-h. Mean daily movement distance and the proportion of daily movements >330 m were compared between strips and blocks. Results were analyzed with ANOVA or Rank-ANOVA when normality and homogeneity were not met following log or square root transformations (Conover and Iman 1981). For all statistical analyses, an alpha threshold of 0.05 was used. Results Hare abundance indices in residual forests and controls Indices of hare abundance were low in all types of residual forest stands as well as in controls (3.3 ± 9.6 [SE] fecal pellets and 2.0 ± 8.0 [SE] browsed twigs per plot for all treatments pooled). There was a significant treatment x year interaction for fecal pellet presence (F = 2.62, P = 0.05). No significant effect of treatments was observed in 1998. However, in 1999, presence/absence of fecal pellets in experimental plots was significantly higher in residual blocks than in upland (F = 2.33, P = 0.02) and riparian strips (F = 2.46, P = 0.01) (Table 1). Vertical cover was positively correlated with the presence of fecal pellets (F = 16.10, P < 0.001; Fig. 1a), while no significant relationship was obtained for the other covariates. Slopes of the relationships were nearly equal among all treatments and controls. Global mean vertical cover was 50.2%; for each treatment, mean vertical cover was 47.7% in upland strips, 49.9% in riparian strips, 49.2% in residual blocks, and 51.0% in controls. Consequently, we included vertical cover in our model as a positive covariate. The presence of browsed twigs, another index of treatment use by hares, showed a significant treatment x year interaction (F = 8.90, P < 0.001; Table 1). Treatments had significant effects only in 1998, when browsed 2008 M.-H. St-Laurent, M. Cusson, J. Ferron, and A. Caron 503 twig presence was significantly higher in blocks than in upland (F = 2.92, P < 0.01) and riparian strips (F = 2.81, P < 0.01), as well as in controls when compared with upland (F = 3.12, P < 0.01) and riparian strips (F = 3.19, P < 0.01). No difference was observed between the two types of strips, or between residual blocks and controls. The presence of browsing in our experimental plots was both significantly and positively related to the availability of deciduous and ericaceous twigs (respectively, F = 4.10, P < 0.05, and F = 5.77, P < 0.05; Figs. 1b and 1c), while vertical and lateral covers present no apparent relationship with browsing. For each treatment, mean percentage of ericaceous twigs was 71.3% (upland strips), 59.7% (riparian strips), 53.9% (residual blocks) and 40.4% (controls), while mean percentage of deciduous twigs was 2.7% (upland strips), 12.6% (riparian strips), 9.2% (residual blocks), and 5.5% (control). In all treatments, browsing occurred mainly on White Birch and Vaccinium spp. (blueberries; considered ericaceous species), moderately on Sheep Laurel and Labrador Tea, while rare occasional browsing (<5% of relative importance in all treatments) was also recorded on alders, Chamaedaphne calyculata Moench (Leatherleaf), Black Spruce, and Balsam Fir (Table 2). Summer home ranges, fidelity and habitat use, and daily movements Eight animals died or disappeared shortly after the beginning of telemetry surveys. Predation caused mortality in four instances, and we suspect natural causes for two others. Two radio-collared animals were lost rapidly following capture. We thus retained data from only 12 individuals: 6 caught in forest strips (3 males and 3 females), and 6 caught in residual blocks (3 males and 3 females). Such a small sample limited our statistical power and, consequently, our ability to detect significant effects of treatments on hare habitat use. However, individual home-range sizes were approximately three times larger in strips (upland and riparian pooled) than in residual blocks (P = 0.07; Table 3) in summer. Hares captured in strips did not confine their activity to where they were first caught, and fidelity to capture stand was Table 1. Mean occurrence of fecal pellets and browsing (% ± SE, according to a cluster sampling scheme) within sampling plots in mature residual or control forest. Means with different letters are significantly different as indicated by a logistic regression conducted on treatments with fixed-year effect, and should be interpreted independently within columns and years. Mean occurrence (% ± SE) of Year Treatment (n) Fecal pellets Browsing 1998 Upland strips (5) 21.3 ± 14.7 a 4.4 ± 2.7 a Riparian strips (5) 41.3 ± 11.4 a 8.0 ± 2.5 a Residual blocks (3) 51.3 ± 14.3 a 30.4 ± 8.7 b Controls (5) 51.7 ± 4.7 a 30.0 ± 5.8 b 1999 Upland strips (5) 28.0 ± 12.3 a 17.3 ± 2.6 a Riparian strips (5) 26.6 ± 7.9 a 42.6 ± 5.2 a Residual blocks (3) 65.4 ± 4.2 b 42.3 ± 19.5 a Controls (5) 48.3 ± 11.0 ab 25.8 ± 10.0 a 504 Northeastern Naturalist Vol. 15, No. 4 significantly higher in residual blocks (P < 0.01; Table 3). Moreover, hares captured in blocks generally remained more associated with blocks than hares caught in strips (P = 0.07) during the 14 weeks of telemetry survey. Consequently, hares from strips tended to use neighbouring large uncut 2008 M.-H. St-Laurent, M. Cusson, J. Ferron, and A. Caron 505 forest areas surrounding logged areas more intensively than hares from blocks (P = 0.08; Table 3). However, there was no significant difference in the percentage of locations in clear-cuts between hares caught in strips and those caught in blocks (P = 0.19; Table 3); open habitat was apparently avoided. No significant difference was detected between daily movements of hares from strips and those from blocks (P = 0.28), but differences among individuals were highly significant (P < 0.001; Table 3). Hares from blocks Table 2. Relative availabilityA (%), useB (%) and importance in hare dietC (%) of browsed species in treatments and controls. Treatments Upland strips Riparian strips Residual blocks Controls Variable Species (n = 5) (n = 5) (n = 3) (n = 5) Availability Balsam Fir 1.1 8.8 8.1 33.5 Black Spruce 38.3 28.9 37.7 31.5 Blueberry 5.4 5.7 2.6 0.9 Labrador Tea 7.4 28.7 25.7 11.2 Sheep Laurel 44.3 15.2 20.0 14.2 White Birch 1.3 0.6 0.1 0.4 OthersD 2.2 12.1 5.8 8.4 Use Balsam Fir 0.0 0.0 0.1 0.1 Black Spruce 0.0 0.0 0.1 0.0 Blueberry 2.1 5.3 40.5 27.7 Labrador Tea 0.0 0.5 0.6 0.3 Sheep Laurel 0.2 2.2 0.4 2.9 White Birch 0.8 2.4 32.1 3.0 OthersD 0.0 0.1 1.2 3.6 Importance Balsam Fir 0.0 0.0 0.7 2.3 Black Spruce 0.0 0.0 1.9 0.8 Blueberry 34.8 38.7 73.0 20.8 Labrador Tea 0.0 12.6 7.2 3.4 Sheep Laurel 27.7 46.1 4.7 42.3 White Birch 37.5 1.9 5.9 1.4 OthersD 0.0 0.8 6.7 29.0 ARelative availability of twigs = 100 * (number of twigs of species x / total number of twigs) BRelative use of available twigs by hares = 100 * (number of browsed twigs of species x / total number of twigs of species x) CRelative importance of browsed twigs in hare diet = 100 * (number of browsed twigs of species x / total number of browsed twigs) DOthers = species for which browsing was also recorded (< 5% in all treatments), i.e., alders, Amelanchier spp. (juneberry), Leatherleaf, and Salix spp. (willows). Figure 1 (opposite page). Vertical cover, mean percentages of deciduous and ericaceous twigs as covariates having significant effect on logit of fecal pellets or browsed twigs’ presence in the logistic regression models. For each treatment (US = upland strips, RS = riparian strips, RB = residual blocks, CO = controls), full lines indicate significant correlations (P < 0.05) while dashed lines indicate no significant linear relation with logit (P > 0.05). Shaded grey bars centered the mean of the covariates (vertical grey dotted lines) where the validity of our conclusions is the highest. 506 Northeastern Naturalist Vol. 15, No. 4 tended to be less prone to make long-distance movements (>330 m) than those from strips (P = 0.10; Table 3) during summer. Discussion Assessing population levels at low density Comparison of hare population levels at low density is often complicated. Considering that a single Snowshoe Hare produces approximately between 445 ± 31 and 579 ± 16 (SE) fecal pellets per day (Hodges 1999, Murray et al. 2005) and in clumps (Krebs et al. 2001b), our estimates are low but representative of the poor habitat quality of eastern boreal spruce forests. For example, mean fecal pellet abundances ranged from 1.6 to 6.4 pellets/m2 in western Québec (Ferron et al. 1998), depending on the phase of the hare density cycle. Near our study area, pellet densities were as low as 0.3 ± 0.1 pellets/m2 in mature Black Spruce stands (St-Laurent et al. 2007). In comparison, mean pellet densities ranged between 85–149 pellets/m2 in Western Canada (Krebs et al. 1987, 2001b). Two other factors may have contributed to the low values of hare indices in our study. The understory in residual forest stands had a mean lateral cover of 57% (in strips) and 67% (in blocks), which is below the optimal threshold of 85% reported by Carreker (1985) and Ferron and Ouellet (1992), although still higher than the 40% threshold necessary to maintain hares (see Carreker 1985). We speculate that low lateral cover density, along with the relative homogeneity of stand structure and composition in our study sites, may explain the absence of significant relationships with hare abundance. Moreover, hares browsed mainly White Birch and some ericaceous twigs, and as ericaceous shrubs were covered by snow during winter and birches were scarce, food became limited. Both unpalatable Balsam Fir and Black Spruce (Bookout 1965, Keith et al. 1984) were abundant in our study area. Table 3. Comparison of home-range size (fixed kernel 95%), fidelity to capture site and to type of residual forest stand, use of clear-cuts and mature forest, and daily movements between Snowshoe Hares from strips (upland and riparian confounded) and hares from blocks, between mid-May and mid-August. A = ANOVA, R-A = Rank-ANOVA, T = treatment, S = sex, and Ind = individual. Dependent Mean ± SE variable Strips (n = 6) Blocks (n = 6) Test Factor F P df Home range (ha) 112.0 ± 12 39.0 ± 6 A T 4.56 0.07 1 S 0.24 0.92 1 T*S 0.16 0.95 1 Fidelity to capture site (%) 20.3 ± 8.4 73.4 ± 13.9 A T 10.70 <0.01 1 Fidelity to type of residual 34.3 ± 13.3 73.4 ± 13.9 R-A T 4.13 0.07 1 forest stand (%) Locations in clearcuts (%) 10.4 ± 2.5 5.0 ± 2.9 R-A T 1.96 0.19 1 Locations in neighboring 55.2 ± 11.8 21.6 ± 12.6 R-A T 3.82 0.08 1 mature forest (%) Daily movements (m) 491.2 ± 40.7 345.6 ± 26.5 R- A T 1.30 0.28 1 Ind (T) 6.91 <0.001 10 Daily movements >330 m (%) 52.0 ± 6.7 34.9 ± 6.7 A T 3.31 0.10 1 2008 M.-H. St-Laurent, M. Cusson, J. Ferron, and A. Caron 507 Hare occurrence vs. treatments Up to 5 years after logging, all types of residual forest were used by hares at least occasionally. However, both indices of the relative use of treatments by hares (fecal pellets and browsing) were significantly greater or tended to be greater most of the time in larger forest stands (residual blocks and controls) than in forest strips (both upland and riparian). In contrast, no difference in pellet density was observed between riparian Balsam Fir strips ranging between 20 to 300 m in width (Darveau et al. 1998). Protection from predators is crucial for the Snowshoe Hare (Krebs et al. 2001c), especially in habitat with poor cover, such as mature Black Spruce forest. In our logistic regression model, vertical cover was a highly significant predictor of the presence of fecal pellets, which suggested that forest structure influenced the abundance of this species. On the other hand, the presence of browsed twigs was significantly related to the availability of deciduous and ericaceous twigs. As a steep slope was observed between logit of browsing and deciduous twig availability, it appeared that deciduous tree species had a greater influence than ericaceous species on habitat use by hares. This relationship was probably due to the low occurrence of deciduous twigs in the understory of Black Spruce stands and its importance in hare diets in Québec (Cusson 2000, Ferron et al. 1998, Potvin 1995). However, presence of browsing in riparian strips was not related to deciduous twig availability, which was low when compared to ericaceous species. There was almost no difference in food availability between strips and blocks (Table 2), and mean abundance of stems and twigs was similar between treatments (Appendix 2). Lack of relationships between lateral cover and hare habitat use may appear problematic. Indeed, lateral cover is known widely as an important predictor of hare abundance in forested habitats (e.g., Carreker 1985, Conroy et al. 1979, Ferron and Ouellet 1992, Ferron et al. 1998, Keith 1990, Monthey 1986). In our case, lateral cover was homogeneous and similar among study sites and treatments that are all composed of mature forest with sparse undercover (upland strips: 56.6 ± 8.0% [SE]; riparian strips: 57.6 ± 7.5%; residual blocks: 66.5 ± 9.5%; controls: 67.6 ± 7.4%). We suggest that homogeneity may explain the absence of effect of lateral cover on hare occurrence in our analyses. It was already observed that hares foraged in regenerating clearcuts as food becomes more available over the years after logging (Monthey 1986). Although abundance of stems and twigs was similar in recent clear-cuts surrounding strips and blocks in our study area (Appendix 2), browsing was significantly lower in clear-cuts adjacent to blocks than in those bordering strips (Appendix 3). Using clear-cuts may thus be related to a greater inability to fulfill habitat requirements within strips than within blocks. This finding supports the idea that hares’ browsing can be influenced by factors other than abundance of food resources (e.g., habitat, cover). However, telemetry data (<10% of locations in clear-cuts) and pellet counts (see Cusson 2000) suggest that hares did not remain for long in 508 Northeastern Naturalist Vol. 15, No. 4 the open, where 4 of 8 dead hares were found. Snowshoe Hares are known to avoid open areas (Keith 1990) and to travel under dense cover (Brocke 1975, Conroy et al. 1979, Ferron and Ouellet 1992). Hare habitat use vs. treatment As mean home-range size was larger than the average area of a residual strip, hares would be forced to: 1) use either the adjacent clear-cut, which offered unsuitable cover, at least shortly after logging; 2) restrict their activity to connecting strips; or 3) emigrate from the logged landscape. Due to the high proportion of clear-cuts in a strip landscape, hares may be subjected to greater predation risk because of sparse hiding cover, excessive edges, and linear and narrow residual strips. Indeed, a fragmented landscape may increase hare mortality (Keith 1990, Sievert and Keith 1985). Because of a limited sample size, we did not conduct survival analyses. However, we suggest that susceptibility to predation may have been comparable between strips and blocks because hiding cover was relatively homogeneous between them. Nevertheless, the larger edge-to-area ratio may force hares to cross clear-cuts more frequently in a strip scenario than in a block configuration. Our telemetry data indicated that hares from strips did not remain confined to the residual forest stand where they were captured and that they used adjacent large areas of uncut forest or other strips more frequently compared to hares from blocks. Further, hares from blocks tended to be more sedentary, and had smaller home ranges and a lower proportion of large daily movements (>330 m) than those from strips. Similarly, Potvin et al. (2005b), using winter track surveys in the landscape we studied, observed hare activity concentrated farthest from the edge of the clear-cut (>20 m). They related this observation to the behaviour of predators. Within the same landscape, Martes americana Turton (American Marten) winter tracks followed strips along their longitudinal axis (Potvin and Bertrand 2004). Potvin et al. (2005b) have also shown that hares are more frequently found in strips adjacent to larger residual forest patches (>25 ha). Residual forest was still present on 32% of our study area, and many strips were connected to large blocks of uncut forest so that strips could have been used more intensively in this area than in landscapes supporting no large patches of mature forest. Also, hares tended to avoid recently logged areas (Cusson 2000, Ferron et al. 1998). These findings suggest that hares avoid edges adjacent to recent clear-cuts, an over-represented habitat in residual strip scenario. Moreover, proportion of daily movements >330 m was higher in both Black Spruce strips (52.0%) and blocks (34.9%) than observed by Brocke (1975) in mixed-wood forest stands (5%). This result suggests that Black Spruce stands are a poorer habitat for hares than mixed-wood forest, forcing them to expand their home range and daily movements. We found evidences that hare activity was concentrated in residual blocks rather than strips. However, the lack of statistically significant differences in our telemetry analyses may be due to our sample size (reduced 2008 M.-H. St-Laurent, M. Cusson, J. Ferron, and A. Caron 509 to 12 individuals) or to spatial heterogeneity between sites of each type of treatment. Indeed, stand structure is the most relevant group of variables explaining relative abundances of Snowshoe Hare, followed by landscape characteristics (St-Laurent et al. 2007, 2008). Management implications Our study suggests that, up to 5 years after logging, configuring residual forest into 20–50-ha blocks might be more suitable to Snowshoe Hares than configuring in 60-m-wide strips, at least in summer. Sizes of individual summer home ranges were relatively large in mature Black Spruce forest; extensive residual forest stands may provide better habitats for hares. Similar conclusions were drawn from a companion study that occurred during winter (Potvin et al. 2005b), so relationships between Snowshoe Hares, strips, and blocks appear consistent year-round. Our results were obtained mainly in summer, during the high phase of the hare density cycle. Although cycle amplitude was low in our study area when compared to northwestern Canada (Ferron and St-Laurent 2008), hares may be forced into using suboptimal habitats such as strips during a high phase, and strip avoidance may be amplified during the low phase. Considering the actual regulation in several Canadian provinces, our results questioned the relevance of configuring residual forest only in strips on a large-scale basis. Such concern is based here on Snowshoe Hare habitat requirements, but can be extended to other species that are more closely correlated to mature forest. It is important to note that negative impacts related to edge proximity or to size and shape of residual forest stands will be lessened as regeneration proceeds. Indeed, regenerating stands 3 m in height can fulfill hare habitat requirements adequately if regeneration is dense and mixed (coniferous and deciduous species intermingled) (St-Laurent et al. 2008). However, large mature forest patches must be protected in the landscape to conserve wildlife associated with mature forest and to maintain ecological processes. Acknowledgments We thank the Ministère des Ressources Naturelles du Québec and the Société de la Faune et des Parcs du Québec for financial and logistic support, and the Fondation de la Faune du Québec for financial support. We also thank the Abitibi-Consolidated company for its support and collaboration. We thank N. Bertrand and F. Potvin for project coordination and for helpful comments during writing, M. Huot for English revision, and C. Paquet and L. Breton for technical assistance. We are grateful to E. Reny-Nolin and G. Daigle for statistical analyses. During field sessions we were supported by a tenacious and efficient team of biologists and technicians: S. Daraîche, N. Gaborit, K. Bergeron, D.-J. Maguire, M.-C. Rancourt, S. Boucher, S. Boisvert and J. Michaud. M.-H. 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Academic Press, San Diego, CA. 383 pp. Zielinski, W.J., and H.B. Stauffer. 1996. Monitoring marten populations in California: Survey design and power analysis. Ecological Applications 6:1254–1267. 2008 M.-H. St-Laurent, M. Cusson, J. Ferron, and A. Caron 513 Appendix 1. Mean abundance of fecal pellets and browsed twigs (± SE) standardized per area unit (1 m2) in mature residual or control forest and clear-cut surrounding residual stands. These raw data were converted into occurrence (presence/absence) to conduct logistic regressions (see Table 1). N/A = no reference is made to clear-cuts for control stands, as there was no surrounding clear-cuts. Mean density of fecal pellets (± SE) Mean density of browsed twigs (± SE) Habitat Year Upland strips Riparian strips Residual blocks Controls Upland strips Riparian strips Residual blocks Controls Mature forest 1998 1.09 ± 2.40 0.85 ± 0.83 1.16 ± 1.48 1.15 ± 1.50 0.03 ± 0.07 0.23 ± 0.58 1.14 ± 3.14 0.77 ± 1.12 1999 0.40 ± 0.59 0.64 ± 1.35 1.77 ± 1.99 1.32 ± 1.56 0.12 ± 0.18 0.96 ± 0.89 1.09 ± 1.53 0.63 ± 1.17 Clear-cut 1998 0.00 ± 0.00 0.02 ± 0.04 0.39 ± 1.03 N/A 0.30 ± 0.42 1.56 ± 2.30 0.15 ± 0.40 N/A 1999 0.03 ± 0.06 0.01 ± 0.02 0.04 ± 0.09 N/A 0.78 ± 1.23 6.09 ± 13.58 0.25 ± 0.38 N/A Appendix 2. Mean abundance (± SE) of stems (>1 cm DBH, <2 m height) and twigs (the last terminal or lateral division of a stem; >10 cm long) in sampling plots located in mature residual or control forest and clear-cuts surrounding residual stands. Means with different letters are significantly different as indicated by a nested two-way ANOVA conducted on treatments. Statistical differences between treatments must be interpreted independently for each year. N/A = no reference is made to clear-cuts for control stands, as there were no surrounding clear-cuts. Mean abundance of stems (± SE) Mean abundance of twigs (± SE) Habitat Year Upland strips Riparian strips Residual blocks Controls Upland strips Riparian strips Residual blocks Controls Mature forest 1998 2.3 ± 0.3 a 1.8 ± 0.3 a 2.8 ± 0.5 a 1.9 ± 0.4 a 15.8 ± 5.1 ab 11.1 ± 0.9 a 17.3 ± 2.1 ab 28.7 ± 6.2 b 1999 2.2 ± 0.3 a 2.2 ± 0.3 a 1.9 ± 0.3 a 2.3 ± 0.2 a 13.1 ± 3.2 a 17.9 ± 3.2 a 13.9 ± 5.3 a 22.4 ± 10.0 a Clear-cut 1998 9.7 ± 1.1 a 11.7 ± 1.6 a 17.2 ± 8.1 a N/A 76.5 ± 22.1 a 60.0 ± 6.3 a 57.3 ± 26.2 a N/A 1999 7.7 ± 2.4 a 14.0 ± 5.1 a 9.1 ± 6.0 a N/A 75.0 ± 34.3 a 93.2 ± 32.3 a 34.1 ± 22.6 a N/A 514 Northeastern Naturalist Vol. 15, No. 4 Appendix 3. Mean occurrence of fecal pellets and browsing (%± SE) in sampling plots located in clear-cuts surrounding residual stands. Means with different letters are significantly different as indicated by a logistic regression conducted on treatments with fixed year effect. Statistical differences between treatments must be interpreted independently for each year. Mean occurrence (% ± SE) of Year TreatmentA (n) Fecal pellets Browsing 1998 Upland strips (5) 0.0 ± 0.0 a 14.0 ± 6.4 a Riparian strips (5) 6.0 ± 4.0 a 18.0 ± 8.6 a Residual blocks (3) 5.6 ± 5.6 a 8.3 ± 8.3 b 1999 Upland strips (5) 6.7 ± 4.1 a 21.3 ± 4.7 a Riparian strips (5) 2.0 ± 2.0 a 40.6 ± 10.5 b Residual blocks (3) 5.6 ± 5.6 a 26.4 ± 6.1 a ANo reference is made to control stands, as there were no surrounding clear-cuts.