Forest composition around wolf ( Canis lupus ) dens in eastern Algonquin Provincial Park, Ontario

Forest composition around wolf (Canis lupus) densin eastern Algonquin Provincial Park, Ontario

D. Ryan Norris, Mary T. Theberge, and John B. Theberge

Abstract: Den-site selection is a poorly understood aspect of wolf (Canis lupus) ecology, particularly for populationsin forested ecosystems. Using a geographic information system and remote-sensing imagery, we examined patterns ofhabitat use around wolf dens in Algonquin Provincial Park, Ontario. Sixteen den sites were sampled for eight habitattypes in their immediately vicinity, as well as at radii of 500, 1000, 1500, and 2000 m. We used a resource-selectionratio to determine whether specific habitat types were preferred or avoided at different radii relative to the total propor-tion of habitat types found within the study area. Wolves established dens in areas with significantly high proportionsof pine forest up to and including a 1000-m radius and low proportions of tolerant and intolerant hardwoods within500 m. We conclude that wolves establish den sites based primarily on the presence of pine forest, a habitat that isfrequently logged within Park boundaries and subject to problems with regeneration after cutting. Dens sites are likelynot limiting in this population, but our results suggest the need to protect current den sites at a relatively large spatialscale. These results also provide unique information to assess the potential for recolonization and reintroduction ofwolf populations in other areas.

Résumé : La sélection d’un site pour sa tanière est un aspect encore mal compris de l’écologie du loup gris (Canis lupus),particulièrement dans les écosystèmes forestiers. Nous avons examiné les patterns d’utilisation de l’habitat au voisinage detanières dans le parc povincial Algonquin au moyen d’un système d’information géographique et d’imagerie par télémétrie.Huit types d’habitat ont été échantillonnés dans le voisinage immédiat de seize tanières de même qu’à des rayons de 500,1000, 1500 et 2000 m des tanières. Nous avons utilisé un rapport de sélection des ressources pour déterminer si certainstypes d’habitat sont recherchés ou évités aux différents rayons relativement aux proportions totales de ces types d’habitatdans toute la zone d’étude. Les loups établissent leur tanière dans des zones où il y a de fortes proportions de forêts de pinsen dedans d’un rayon de 1000 m et de faibles proportions de bois francs tolérants ou intolérants en dedans d’un rayon de500 m. Les loups choisissent donc, pour établir leur tanière, des sites à dominance de pins, habitats souvent soumis à lacoupe à l’intérieur des limites du parc et sujets à des problèmes de regénéation après la coupe. Les sites propices àl’établissement d’une tanière ne sont sans doute pas des facteurs limitants pour cette population de loups, mais nos résultatssoulignent la nécessité de protéger les sites actuels des tanières sur une échelle spatiale assez vaste. Ces résultats fournissentégalement une information inédite pour évaluer le potentiel de recolonisation et de réintroduction de populations de loupsdans d’autres régions.

[Traduit par la Rédaction] 872

Norris et al.Introduction

Understanding patterns of habitat use in wolves is importantfor conserving, managing, and restoring populations (Mladenoffet al. 1995; Massolo and Meriggi 1998; Kunkel and Pletscher2000). Den-site habitat use is one of the least understoodaspects of wolf (Canis lupus) ecology (Heard and Williams

1992), despite the fact that dens are essential for the success-ful rearing of offspring and likely important for subsequentrecruitment into the population. Current knowledge of den-site habitat use is limited to anecdotal evidence which sug-gests that wolves establish dens in areas with specificmicrohabitats, for example, near elevated ridges or in well-drained, sandy soils where tunnels can be easily excavated(Mech 1970; Ballard and Dau 1983). Wolves can travel longdistances over short periods (Gese and Mech 1991; Cook etal. 1999) and should be able to assess habitat characteristicsover a wide geographic range. Measures have already beentaken to protect den sites from human intrusion (Wydevenand Shultz 19923; Thiel et al. 1998), but information to ac-curately determine the appropriate area or level of protectionis unavailable.

Geographic information systems (GISs) have provided auseful tool to analyze landscape-level habitat use in mammalsand birds by linking telemetry locations with vegetation pat-terns over various spatial scales (e.g., Florida panther, Felisconcolor coryi (Maehr and Cox 1995); Spotted Owl, Strixoccidentalis (Lehmkuhl and Raphael 1993); black-tailed deer,Odocoileus hemionus (Chang et al. 1995); wolf (Mladenoff

866

Can. J. Zool. 80: 866–872 (2002) DOI: 10.1139/Z02-067 © 2002 NRC Canada

Received 8 August 2001. Accepted 28 March 2002. Publishedon the NRC Research Press Web site at http://cjz.nrc.ca on24 May 2002.

D.R. Norris.1 Department of Biology, Queen’s University,Kingston, ON K7L 3N6, Canada.M.T. Theberge and J.B. Theberge.2 School of Planning,University of Waterloo, Waterloo, ON N2L 3G1, Canada.

1Corresponding author (e-mail: [email protected]).2Present address: R.R. 3, Site 25, Compartment 82, Oliver,BC V0H 1T0, Canada.

3A.P. Wydeven and R.N. Shultz 1992. Management policy forwolf den and rendezvous sites. Unpublished report,Wisconsin Department of Natural Resources, Park Falls.Cited in Fritts et al. (1994).

J:\cjz\cjz80\cjz-05\Z02-067.vpWednesday, May 22, 2002 10:50:30 AM

Color profile: DisabledComposite Default screen

et al. 1995)). This method can also be applied to the study ofhabitat requirements around reproductive sites (Baker et al.1995; Ripple et al. 1997; Swindle et al. 1999). Samplinghabitat types at various distances (i.e., with circular buffers)from a site allows researches to determine the scale within alandscape at which habitat selection could operate (e.g.,Baker et al. 1995).

Assessing landscape-level habitat use for wolves in for-ested ecosystems is important because many populations areestablished in regions where there are intensive forestry prac-tices, hunting, and (or) development (Mladenoff et al. 1995;Kunkel and Pletscher 2000; Larivière et al. 2000; this study).In addition, proposed reintroduction of wolves into forestedareas of the northeastern United States will require detailedknowledge of habitat requirements (Harrison and Chapin 1998;Mladenoff and Sickley 1998). However, determining pat-terns of habitat use is difficult because tracking individualsand locating dens can be expensive and time consuming.Furthermore, because of the high fidelity of females to densites, obtaining adequate independent samples is frequentlyproblematic (Ciucci and Mech 1992).

To examine if wolves establish dens on the basis of forestcomposition at the landscape level, we sampled 16 den sitesfrom 16 different alpha females found during an 11-yearstudy of a population in Algonquin Park, Ontario (Theberge1998). Using classifications derived from a remote-sensingimage, our goals were to (i) identify the vegetation typesclosely associated (preferred) and avoided in establishingden sites and (ii) determine the distance from the den sitethat preference or avoidance of these habitat types occurs.

The proportion of each vegetation type was recorded in thearea immediately surrounding den sites, as well as at radii of500, 1000, 1500, and 2000 m (Fig. 1). If wolves establishdens within specific habitat type(s), then the proportion ofthese habitat(s) should be significantly different from the ac-tual proportions found within the study area (Johnson 1980).Because the areas of heaviest use for both adults and pupsduring the breeding season have been found to be within1 km of active dens (J.B. Theberge, unpublished data), wepredict that habitat selection should take place up to and in-cluding this radius from the den. However, because of theirextreme mobility wolves are likely able to assess habitatsover wider spatial scales, so we included habitat measure-ments at 1500 and 2000 m from den sites in our analysis.Most of the dens found by Joslin (1968) in Algonquin Parkwere located in areas dominated by pine species. Therefore,we predict that pine forest types will be a preferred habitatat the landscape level.

Methods

Study areaAlgonquin Provincial Park (48°N, 78°W) is 7571 km2 and

ranges in elevation from 180 to 380 m in the east and up to580 m in the west. The park lies in a transition zone betweenboreal forest to the north and Great Lakes – St. Lawrencelowlands to the south (Rowe 1972). During the 11-year study,radio-collared wolves held territories in eastern AlgonquinPark and all den sites found were from this area. The easternhalf of the Park is dominated by pine/intolerant hardwood(white pine (Pinus strobus), red pine (Pinus resinosa), jack

pine (Pinus banksiana), white birch (Betula papyrifera), largetooth aspen (Populus tremuloides), and red oak (Quercusrubra)). Lowlands contain primarily balsam fir (Abies balsamea)and black spruce (Picea mariana).

Den sitesAs part of a study on the ecology of wolves in the Park

(Theberge 1998), 16 dens were found belonging to membersof packs with at least one radio-collared wolf. See Forbesand Theberge (1996) and Cook et al. (1999) for details ontrapping, radio-collaring, and telemetry. On the basis of te-lemetry locations, areas of heavy use during May and Junewere identified as possible denning sites. Dens were foundby walking into these areas and searching likely locationsafter the denning period had ceased. Once a den was found,bones, scat, trampled vegetation, and tracks at the site wereindicators that it had been used for denning that year. Fivedens were used by wolves from the same pack but in differ-ent years. None of the 16 dens belonged to the same breed-ing female.

Habitat analysisHabitat types for eastern Algonquin Park were derived

from a multispectral scanner image (pixel size 50 × 50 m)taken from a LANDSAT satellite on 12 May 1986. The im-age was imported and classified into eight habitat types inARC/INFO® (version 7.0.1, ERSI, Redlands, California), avector-based GIS. Pixels were amalgamated into 100 × 100 mcells because the image could not be accurately classified at

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Norris et al. 867

den site

500m

N

Fig. 1. Procedure used to sample habitat types at various dis-tances from dens and random locations. Small squares representindividual cells of one habitat type classified from the LAND-SAT image. For the “site analysis”, the central cell and the eightcells immediately surrounding the den were sampled. For the“radii analysis”, eight pixels were sampled at each of the cardi-nal axes (N, S, E, W) at 500, 1000, 1500, and 2000 m. Only the500-m radius is shown here. Equal numbers of cells, therefore,were sampled at all radii.



greater resolution. Ecologically similar forest types that couldnot be separated were summed (see Table 1 for a completedescription). In total, six vegetation classification types wereused representing the major forest types of the Park identi-fied by Rowe (1972). Water (i.e., lakes and major rivers)and cleared land (e.g., gravel pits, campgrounds) were the7th and 8th classification types. Between May and August1989 and 1990, we ground-truthed (n = 75) all habitat typesby walking into areas, recording locations, and then comparingour classification with the image classification. The imagecorrectly classified habitats greater than 90% of the time.

The remote-sensing image was imported into SPANS(SPANS® Explorer™, version 6.0, Tydac Technologies Inc.,Nepean, Ontario, Canada), a raster-based GIS, using a 100 ×100 m grid cell size. Locations of den sites were recorded ona UTM topographical map and also imported into SPANS.The proportion of habitat types were sampled around eachden site by recording it in the cell where each site was locatedplus habitat types in the eight surrounding cells (Fig. 1). Theproportion of habitat types, therefore, was expressed as apercentage of the total number of cells. We then generatedcircular buffers with radii of 500, 1000, 1500, and 2000 maround each den site. For each buffer, we sampled 9 cells atfour points (north, south, east, and west) for a total of 36cells (Fig. 1). Radii were therefore sampled equally withinand between sites.

We measured the total availability of each habitat type(expressed as a proportion) from the LANDSAT image. Thestudy area was defined as the eastern portion of AlgonquinPark (roughly a third of the total Park area) and encom-passed the outermost boundaries of radio-collared wolf terri-tories during the 11-year study. We determined the selectionratio (SR) for each habitat type at each site (0-m radius) andat each radii (radii 500–2000 m) at the 16 dens. The SR wasexpressed as the ratio of available habitat to used habitat(Manly et al. 1993):

wi = oi /πi

where oi is the proportion of ith habitat sampled at or aroundthe den site and πi is the proportion of the ith habitat typefound within the study area. SR values above 1 indicatedthat a habitat type is preferred relative to its overall availabil-ity in the study area. Conversely, a ratio below 1 indicatedthat the habitat was underutilized relatively to its availability.

The significance of each SR value was evaluated by calcu-lating Bonferroni-corrected confidence intervals derived fromManly et al. (1993):

wi ± Zα/(2I)SE(wi)

where I is the number of habitat types (n = 8), α = 0.1, andSE is the standard error of wi. If the confidence intervaloverlapped with 1, then the habitat type was considered tohave been used in relative proportion to its availability (i.e.,nonsignificant).

Results

The proportions of each habitat type at all five samplingdistances and within the entire study area are shown in Fig. 2.The proportion of pine forests surrounding den sites wasconsistently above the total proportion found within the studyarea (Fig. 2). Confidence intervals showed that the high pro-portion of pine forests around den sites was significant up toand including the 1000-m radius (Table 2). This pattern alsooccurred at the 1500- and 2000-m radii, although the SR valueswere not significant (Table 2). Tolerant hardwoods occurredsignificantly less often than expected at all radii except 1000 m(Table 2). At the 1000-m radius, the SR value was less than1 but was nonsignificant (Table 2). Intolerant hardwoods hadSR values significantly less than 0 at the den and at 500 m.Nonsignificant SR values less than 1 for intolerant hard-woods continued up to and including the 2000-m radius. Theproportion of pine/poplar forest around den sites was consis-tently higher than the proportion found within the study areawith the exception of the 2000-m radius (Fig. 2). Because ofthe high variability of pine/poplar between sites, however,all of the SR confidence intervals overlapped with 1. Majorwater bodies were avoided in areas immediately surroundingthe dens and also occurred less often than expected at the1000-m radius (Table 2).

Cleared land was not recorded within the 1500-m radiusin any of the 16 den sites, despite this habitat type makingup 1.5% of the total habitat found within the study area(Fig. 2). Both wetland and lowland conifer habitats showedrelatively high variability between sites and consistently ex-hibited nonsignificant values.

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868 Can. J. Zool. Vol. 80, 2002

Pixel classification Forest or habitat types included* Description

Wetlands Wetlands: submergent and emergent vegetation, bogs >50% wetlandsIntolerant hardwoods Birch/poplar, poplar/birch >70% intolerant hardwoodsTolerant hardwoods Maple/beech, maple/yellow birch, maple/beech/yellow birch,

oak species>70% tolerant hardwoods

Pine/poplar Pine species and poplar species >70% pine and poplar combined but not>70% of either

Pine Pine (jack pine, red pine, white pine) >70% pineLowland conifer Black spruce/white spruce, balsam fir, cedar or any

combination>70% lowland species

Water Lakes, major rivers, first-order streamsCleared land Developed areas, clearcut (<5 years) >70% cleared land

*Two species or genus complexes combined with a solidus indicate a mixed forest with the first species or genus composing greater than 50% of theforest type.

Table 1. Habitat types and descriptions of the eight classifications derived from the LANDSAT image.



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Norris et al. 869

Discussion

This is the first study to examine landscape-level habitatuse of wolf reproductive sites. Results indicate that wolvesin eastern Algonquin Park establish dens in areas surroundedby a relatively high proportion of pine forest within 1 kmfrom the den site. The importance of pine is also supportedby the nonsignificant SR values above 1 for pine/poplar habitat.Within 500 m, dens were established in areas with signifi-cantly low proportions of tolerant and intolerant hardwoods.Tolerant hardwoods were avoided up to and including 2 kmfrom the den site.

Why are pine forests a preferred habitat to establish densites? Wolves may prefer to excavate dens in habitats thathave well-drained, sandy soils such as those favored by pine(Mech 1970; Ballard and Dau 1983). Coarser soils may alsoaccount for the avoidance of tolerant and intolerant hard-woods immediately surrounding the den sites. All but oneden in our study was dug into earth, three of them in previ-ously disturbed soil of 50+-year-old, collapsed root cellarsleft from logging, and one on the lip of a sand pit used yearspreviously for road construction. Five dens were dug aroundthe roots of large, live white pine trees.

Pine forest occurred more frequently not only at the densites but up to a 1-km radius from the dens. One explanationis that the occurrence of a high proportion of pine at this dis-tance is a by-product of habitat selection immediately sur-rounding the den. If this were the case, we would expecthabitat types within the study area to be relatively unfragmented(i.e., large blocks of continuous habitat) so that selection ofa site based on immediate site characters is reflected at alarger scale. However, we are not convinced that micro-habitat selection is responsible for patterns observed at largerscales. Algonquin Park lies in the transition zone betweenboreal forest to the north and Great Lakes – St. Lawrence

lowlands to the south. The landscape is highly heterogeneousand forest-type areas are frequently as small as 1–2 ha. There-fore, selection of a forest type for its microhabitat character-istics may not be translated to patterns at larger distancesfrom the site. In addition, Algonquin Park has been activelylogged for over a century. Hardwood species typically out-compete pine species after disturbance (Ziegler 1995; Weirand Johnson 1998). This phenomenon may have made Algon-quin Park’s landscape more patchy than it was historicallywhen pine was the dominant forest type. Fire suppressionmay also contribute to a decrease in the abundance of whitepine and jack pine, which are dependent on high temperaturesfor seed dispersal (Beaufait 1960; Kimmins 1987; Guyetteand Dey 1995).

Alternatively, wolves may prefer to establish dens in areasof pine forests because this habitat is associated with low el-evations and less understory. Both of these characteristicscould facilitate travel to and from the den by adults, an im-portant attribute given that packs spend large amounts oftime near dens (Kolenosky and Johnston 1967; Mech andMerrill 1998; J.B. Theberge, unpublished data). The avoid-ance of habitat types characteristic of upland habitats (i.e.,hardwoods) also supports this hypothesis. If wolves selecthabitat around dens to facilitate travel routes, we would ex-pect this pattern to also occur within wolf territories. UsingGIS and satellite imagery to analyze habitat use of wolves innorthern Wisconsin, Mladenoff et al. (1995) found that territo-ries had higher proportions of mixed conifer/deciduous for-est and wetlands and lower proportions of deciduous forestthan areas not used by wolves. Telemetry locations of radio-collared wolves in Algonquin Park show a similar pattern; asignificant proportion of locations fall within lowland foresttypes compared with the overall abundance of these habitatsin the area (D.R. Norris and J.B. Theberge, unpublisheddata). Low elevations combined with a high percentage of

0

0.1

0.2

0.3

0.4

wetlands intolerant

hardwood

tolerant

hardwood

pine/poplar pine lowland

conifer

cleared land water

site

500 m

1000 m

1500 m

2000 m

study area

pro

port

ion

ofhabitatty

pes

Fig. 2. Proportion of habitat types found within the entire study area and for 16 den sites (mean + SE) sampled at five different dis-tances from wolf dens. “Site” refers to habitats that were sampled immediately surrounding the dens.



canopy cover in coniferous forests may also provide off-spring with better protection from harsh abiotic conditions.

None of the dens we analyzed were within 1.5 km ofcleared land, suggesting that wolves are intolerant of humanactivity. Wolves in this population are frequently shot orsnared in areas adjacent to the park where they travel to adeeryard in winter (Cook et al. 1999). In our image classifi-cation, cleared land primarily included campgrounds, gravelpits, and ranger stations (there are many logging roads in thepark but resolution was not sufficient to detect them). In

contrast to our results, Thiel et al. (1998) summarized a num-ber of instances where wolves established dens near areasof high-level human activity. We interpret their evidencewith caution because it is not clear whether these incidenceswere typical of a general pattern found in those populations.Nevertheless, our results are difficult to compare with others,since human-activity level in Algonquin Park is relativelylow.

Our data also indicate that dens tended to be establishedaway from major water bodies. One den was 5 m from a

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870 Can. J. Zool. Vol. 80, 2002

Bonferroniconfidence limit

Samplingdistance (m)* Habitat type wi SE(wi) Lower† Upper Significance

Site Pine 1.90 0.33 1.09 2.71 >1Wetland 1.19 0.87 0.00 3.37 nsPine/poplar 1.12 0.32 0.32 1.92 nsLowland conifer 0.94 0.60 0.00 2.44 nsIntolerant hardwoods 0.62 0.15 0.25 0.99 <1Tolerant hardwoods 0.23 0.16 0.00 0.63 <1Water 0.14 0.14 0.00 0.47 <1Cleared land 0.00 0.00 — — —

500 Pine 1.65 0.21 1.11 2.18 >1Wetland 1.03 0.42 0.00 2.09 nsPine/poplar 1.21 0.15 0.84 1.58 nsLowland conifer 1.61 0.57 0.19 3.03 nsIntolerant hardwoods 0.61 0.11 0.35 0.88 <1Tolerant hardwoods 0.43 0.16 0.03 0.83 <1Water 0.58 0.41 0.00 1.61 nsCleared land 0.00 0.00 — — —

1000 Pine 1.50 0.18 1.04 1.95 >1Wetland 0.73 0.37 0.00 1.65 nsPine/poplar 1.37 0.18 0.92 1.81 nsLowland conifer 1.30 0.42 0.24 2.36 nsIntolerant hardwoods 0.75 0.13 0.42 1.08 nsTolerant hardwoods 0.55 0.27 0.00 1.21 nsWater 0.24 0.20 0.00 0.75 <1Cleared land 0.00 0.00 — — —

1500 Pine 1.41 0.22 0.87 1.96 nsWetland 1.54 0.43 0.47 2.61 nsPine/poplar 1.23 0.16 0.82 1.64 nsLowland conifer 1.36 0.40 0.37 2.35 nsIntolerant hardwoods 0.78 0.10 0.53 1.03 nsTolerant hardwoods 0.30 0.15 0.00 0.67 <1Water 0.30 0.30 0.00 1.07 nsCleared land 0.00 0.00 — — —

2000 Pine 1.23 0.19 0.76 1.71 nsWetland 1.51 0.35 0.65 2.38 nsPine/poplar 0.97 0.08 0.78 1.17 nsLowland conifer 1.46 0.38 0.51 2.40 nsIntolerant hardwoods 0.92 0.16 0.53 1.32 nsTolerant hardwoods 0.43 0.20 0.00 0.93 <1Water 0.47 0.23 0.00 1.05 nsCleared land 1.16 0.81 0.00 3.18 ns

Note: Confidence limits were either >1, <1, or overlapped with 1 (ns, nonsignificant).*Habitats were sampled from the area immediately surrounding dens; see Methods for details.†The lowest possible confidence limit is 0.00.

Table 2. Selection ratio values and Bonferroni confidence intervals for habitat types in allfour sampling distances from den sites (n = 16).



lake, and two dens were within 30 m of a river. The LAND-SAT image used in our analysis did not pick up streams andsecond-order or higher rivers. Smaller water bodies, how-ever, were within 80 m of all but 1 other den, and 11 denswere within 30 m. Represented were bog/fen complexes (8),streams (3), and a small pond (1). One den was 400 m fromthe nearest water. Similarly, five of six dens found by Joslin(1968) in Algonquin Park were within 20 m of water andone was within 200 m. In Alaska, Ballard and Dau (1983)found that the average distance from dens to water was257 m, whereas the mean interden distance was 45.3 km.

Although the landscape composition may have changedslightly during the course of the study, we feel these changeswere unlikely to affect our results. Less than 2% of Algon-quin Park is logged per year and none of the den sites werelocated near logged areas. Furthermore, regenerating areasare mostly composed of hardwoods, making our conclusionsabout the strong selection of pine forest conservative. How-ever, we acknowledge that further analyses of stand age needto be conducted.

Wolves may also be establishing den sites based on habitatcharacteristics at higher or lower spatial scales. Many organ-isms have been shown to select habitats at multiple spatial(and temporal) scales (e.g., Bergin 1992; Pedlar et al. 1997;Pribil and Picman 1997). In our case, alpha females may es-tablish dens where there is a high overall abundance of prey(Heard and Williams 1992) or where specific microhabitatconditions are present (Ballard and Dau 1983).

Both Chapman (1977) and Ciucci and Mech (1992) be-lieved that den sites were not limiting in their study popula-tions. Their evidence was based primarily on the availabilityof microhabitat features. If wolves select den sites on thebasis of partially or entirely on landscape-habitat features, assuggested by our data, then certain habitats at this spatialscale may influence the distribution of packs. In eastern Al-gonquin Park, pine forests make up 21% of the total area ofhabitat (Fig. 2). At present, therefore, available habitat islikely not limiting. However, logging occurs in more than70% of the Park and many pine stands continue to be harvested(Algonquin Forestry Authority 1994). In the southern por-tion of their range, pine species are frequently out-competedby hardwoods after logging or when natural fires are sup-pressed (McClom 1983; Brummels and Carelton 1989; Ziegler1995). The potential for habitat limitation therefore existsand wildlife managers should be aware of the possibility.

The preference of wolves to den near pine forests may nothave direct consequences for survival or reproduction in thispopulation. Future research should focus on the fitness-relatedconsequences of den-site occupancy and habitat use in wolfpopulations. Most dens analyzed in our study, however, showedsimilar patterns of habitat use, suggesting that selection ofspecific habitats has occurred over a long term. Determiningthe amount of habitat available for dens in mixed-forestecosystems will be important in assessing the potential forrecolonization and reintroduction efforts (Mladenoff and Sickley1998).

Acknowledgements

We thank World Wildlife Fund Canada, the WildlandsLeague, International Fund for Animal Welfare, the Natural

Sciences and Engineering Research Council of Canada, Friendsof Algonquin Park, Mountain Equipment Co-op, and privatedonors for financial support. Students earning graduate de-grees who contributed to these data are Graham Forbes, LeeSwanson, Joy Cook, and John Pisapio. Technical staff at theUniversity of Waterloo helped with image analysis, especiallyJoe Piwowar and Marco Dumancic. Scott Tarof providedconstructive comments on earlier versions of the manuscript.

References

Algonquin Forestry Authority. 1994. Timber management plan sum-mary, 1995–2015. Algonquin Forestry Authority, Pembroke, Ont.

Baker, B.W., Cade, B.S., Mangus, W.L., and McMillen, J.L. 1995.Spatial analysis of sandhill crane nesting habitat. J. Wildl. Manag.59: 752–758.

Ballard, W.B., and Dau, J.R. 1983. Characteristics of gray wolf,Canis lupus, den and rendezvous sites in southcentral Alaska.Can. Field-Nat. 97: 299–302.

Beaufait, W.R. 1960. Some effects of high temperatures on thecones and seeds of jack pine. For. Sci. 6: 194–199.

Bergin, T.M. 1992. Habitat selection by the western kingbird inwestern Nebraska: a hierarchical analysis. Condor, 94: 903–911.

Brummels, G., and Carleton, T.J. 1989. The vegetation of post-logged black spruce lowlands in central Canada. II. Understoryvegetation. J. Appl. Ecol. 26: 321–339.

Chang, K.-T., Verbyla, D.L., and Yeo, J.J. 1995. Spatial analysis ofhabitat selection by Sitka black-tailed deer in southeast Alaska,U.S.A. Environ. Manag. 19: 579–589.

Chapman, R.C. 1977. The effects of human disturbance on wolves(Canis lupus). M.S. thesis, University of Alaska, Fairbanks.

Ciucci, P., and Mech, L.D. 1992. Selection of wolf dens in relationto winter territories in northwest Minnesota. J. Mammal. 73:899–905.

Cook, S.J., Norris, D.R., and Theberge, J.B. 1999. Spatial dynam-ics of a migratory wolf population in winter in south-centralOntario, 1990–1995. Can. J. Zool. 77: 1740–1750.

Forbes, G.J., and Theberge, J.B. 1996. Cross-boundary manage-ment of Algonquin Park wolves. Conserv. Biol. 10: 1091–1097.

Fritts, S.H., Bangs, E.E., and Gore, J.F. 1994. The relationship ofwolf recovery to habitat conservation and biodiversity in thenorthwestern United States. Landsc. Urban Plann. 28: 23–32.

Gese, E.M., and Mech, L.D. 1991. Dispersal of wolves (Canislupus) in northeastern Minnesota, 1969–1989. Can. J. Zool. 69:2946–2955.

Guyette, R.P., and Dey, D.C. 1995. Age, size, and regeneration ofold-growth white pine at Dividing Lake Nature Reserve, Algon-quin Park, Ontario. In Forest Research Report No. 131. OntarioForest Research Institute, Toronto. pp. 1–11.

Harrison, D.J., and Chapin, T.G. 1998. Extent and connectivity ofhabitat for wolves in eastern North America. Wildl. Soc. Bull.26: 767–775.

Heard, D.C., and Williams, T.M. 1992. Distribution of wolf denson migratory caribou ranges in the Northwest Territories, Can-ada. Can. J. Zool. 70: 1504–1510.

Johnson, D.H. 1980. The comparison of usage and availabilitymeasurements for evaluating resource preference. Ecology, 61:65–71.

Joslin, P.B.W. 1968. Movements and home sites of timber wolvesin Algonquin Park. Am. Zool. 7: 279–288.

Kimmins, J.P. 1987. Forest ecology. Macmillan Publishing Co.,New York.

Kolenosky, G.B., and Johnston, D.H. 1967. Radio-tracking timberwolves in Ontario. Am. Zool. 7: 289–303.

© 2002 NRC Canada

Norris et al. 871



© 2002 NRC Canada

872 Can. J. Zool. Vol. 80, 2002

Kunkel, K.E., and Pletscher, D.H. 2000. Habitat factors affectingvulnerability of moose to predation by wolves in southeasternBritish Columbia. Can. J. Zool. 78: 150–157.

Larivière, S., Jolicoeur, H., and Crête, M. 2000. Status and conser-vation of the gray wolf (Canis lupus) in wildlife reserves ofQuébec. Biol. Conserv. 94: 143–151.

Lehmkuhl, J.F., and Raphael, M.G. 1993. Habitat pattern aroundspotted owl locations on the Olympic Peninsula, Washington. J.Wildl. Manag. 57: 302–315.

Maehr, D.S., and Cox, J.A. 1995. Landscape features and Panthersin Florida. Conserv. Biol. 9: 1008–1019.

Manly, B.F.J., McDonald, L.L., and Thomas, D.L. 1993. Resourceselection by animals: statistical analysis for field studies. Chap-man and Hall, New York.

Massolo, A., and Meriggi, A. 1998. Factors affecting habitat occu-pancy by wolves in northern Apennines (northern Italy): a modelof habitat suitability. Ecography, 21: 97–107.

McClom, R.G. 1983. Postcut classification of recent cutover. 1972–1982: summary of results. Ontario Ministry of Natural Resources,Toronto.

Mech, L.D. 1970. The wolf: ecology and behavior of an endan-gered species. University of Minnesota Press, Minneapolis.

Mech, L.D., and Merrill, S.B. 1998. Daily departure and returnpatterns of wolves, Canis lupus, from a den at 80°N latitude.Can. Field-Nat. 112: 515–517.

Mladenoff, D.J., and Sickley, T.A. 1998. Assessing potential graywolf restoration in the northeastern United States: a spatial pre-diction of favourable habitat and potential population levels.J. Wildl. Manag. 62: 1–10.

Mladenoff, D.J., Sickley, T.A., Haight, R.G., and Wydeven, A.P.1995. A regional landscape analysis and prediction of favorablegray wolf habitat in the northern Great Lakes region. Conserv.Biol. 9: 279–294.

Pedlar, J.H., Fahrig, L., and Merriam, H.G. 1997. Raccoon habitatuse at 2 spatial scales. J. Wildl. Manag. 61: 102–112.

Pribil, S., and Picman, J. 1997. The importance of using propermethodology and spatial scale in the study of habitat selectionin birds. Can. J. Zool. 75: 1835–1844.

Ripple, W.J., Lattin, P.D., Hershey, K.T., Wagner, F.F., and Meslow,E.C. 1997. Landscape patterns around spotted owl nest sites insouthwestern Oregon. J. Wildl. Manag. 61: 151–158.

Rowe, J.S. 1972. Forest regions of Canada. Can. Dep. Environ.For. Serv. Publ. No. 1300.

Swindle, K.A., Ripple, W.J., Meslow, E.C., and Schafer, D. 1999.Old-forest distribution around spotted owl nests in central cas-cade mountains, Oregon. J. Wildl. Manag. 63: 1212–1221.

Theberge, J.B. 1998. Wolf country: eleven years of tracking theAlgonquin wolves. McClelland and Stewart Inc., Toronto, Ont.

Thiel, R.P., Merril, S., and Mech, L.D. 1998. Tolerance by denningwolves, Canis lupus, to human disturbance. Can. Field-Nat. 112:340–342.

Weir, J.M.H., and Johnston, E.A. 1998. Effects of escaped settle-ment fires and logging on forest composition in the mixedwoodboreal forest. Can. J. For. Res. 28: 459–467.

Ziegler, S.S. 1995. Relict eastern white pine (Pinus strobus L.)stands in southwestern Wisconsin. Am. Midl. Nat. 133: 88–100.



Documents

Forest composition around wolf ( Canis lupus ) dens in eastern Algonquin Provincial Park, Ontario