Hare Abundance Research Articles

Is the relationship between predator and prey abundances related to climate for lynx and snowshoe hares?

Context Predator dynamics may be related to prey abundance and influenced by environmental effects, such as climate. Predator–prey interactions may be represented by mechanistic models that comprise a deterministic skeleton with stochastic climatic forcing. Aims The aim of this study was to evaluate the effects of climate on predator–prey dynamics. The lynx and snowshoe hare predator–prey system in the Kluane region of the Yukon, Canada, is used as a case study. The specific hypothesis is that climate influences the relationship between lynx and hare abundance. Methods We evaluate 10 linear relationships between predator and prey abundance and effects of climate. We use data on lynx and snowshoe hare abundance over 21 years in the Yukon as the predator–prey system, and three alternative broad-scale climate indices: the winter North Atlantic Oscillation (NAO), the Pacific North American (PNA) index and the North Pacific index (NPI). Key results There was more support, as assessed by Akaike weights (ωi = 0.600), evidence ratio (=4.73) and R2 (=0.77) for a model of predator (lynx) and prior prey (hare) abundance with an effect of prior climate (winter NAO) when combined in a multiplicative, rather than in an additive, manner. The results infer that climate changes the amplitude of the lynx cycle with lower predator (lynx) abundance with positive values of winter NAO for a given hare density. Conclusions The study provides evidence that predator–prey dynamics are related to climate in an interactive manner. The ecological mechanism for the interactive effect is not clear, and alternative hypotheses are proposed for future evaluation. Implications The study implies that changes in climate may alter predator–prey relationships.

Predator‐Mediated Indirect Effects of Snowshoe Hares on Dall's Sheep in Alaska

ABSTRACTIndirect interactions among species can strongly influence population dynamics and community structure but are often overlooked in management of large mammals. We estimated survival of Dall's sheep (Ovis dalli) in the central Alaska Range, USA, during years of differing snowshoe hare (Lepus americanus) abundance to test whether indirect interactions with a cyclic hare population affect Dall's sheep either negatively, by subsidizing predators (apparent competition), or positively, by diverting predation (apparent commensalism). Annual survival of adult female sheep was consistently high (0.85 for all yr and age classes combined). In contrast, annual estimates of lamb survival ranged from 0.15 to 0.63. The main predators of lambs were coyotes (Canis latrans) and golden eagles (Aquila chrysaetos), which rely on hares as their primary food and prey on lambs secondarily. Coyotes and eagles killed 78% of 65 radiocollared lambs for which cause of death was known. Lamb survival was negatively related to hare abundance during the previous year, and lamb survival rates more than doubled when hare abundance declined, supporting the hypothesis of predator‐mediated apparent competition between hares and sheep. However, stage‐specific predation and delays in predator responses to changes in hare numbers led to a positive relationship between abundance of adult Dall's sheep and hares. Lacking reliable estimates of survival, a manager might erroneously conclude that hares benefit sheep. Thus, support for different indirect effects can be obtained from different types of data, which demonstrates the need to determine the mechanisms that create indirect interactions. Long‐term survey data suggest that predation by coyotes is limiting this sheep population below levels typical when coyotes were rare or absent. Understanding the nature of indirect interactions is necessary to effectively manage complex predator–prey communities.

Relationship Between Fecal Pellet Counts and Snowshoe Hare Density in Western Wyoming

ABSTRACT Snowshoe hares (Lepus americanus) are an important prey species for Canada lynx (Lynx canadensis) and are considered critical for lynx population persistence. Determination of snowshoe hare distribution and abundance is needed by land management agencies for lynx conservation. An accepted approach for estimating snowshoe hare abundance is the use of fecal‐pellet plot counts. Locally derived regression equations are preferred for accurate calibration of pellet counts to snowshoe hare density due to local differences in pellet deposition and decomposition. We used linear regression to examine correlations between snowshoe hare density, as determined by mark–recapture estimates, and pellet plot counts on both uncleared plots and annually cleared plots on the Bridger‐Teton National Forest, western Wyoming, USA. We found significant correlations between snowshoe hare density estimates and fecal pellet counts for both uncleared and annually cleared pellet counts; however, the relationship was stronger (higher r) when using pellet counts from annually cleared plots. In addition, we found that adjusting the buffer size by omitting hard habitat edges (not used by hares) around trapping grids improved correlations between snowshoe hare density and fecal pellet counts for both uncleared plots and annually cleared plots. Though precision is sacrificed when using uncleared plots, they may be useful as a coarse index of habitat use by snowshoe hares. Our derived regression equations may be useful to identify important foraging habitat for Canada lynx in western Wyoming. Land managers responsible for conserving snowshoe hare habitat in western Wyoming may use these equations to monitor changes in hare populations among habitats and during prescribed management actions.

Movement paths reveal scale-dependent habitat decisions by Canada lynx

We documented the relative grain at which Canada lynx (Lynx canadensis) perceive habitat heterogeneity using fractal dimension of foraging paths. We evaluated whether lynx expended greater foraging effort (i.e., greater fractal dimension of movement paths) in patches with the highest density of snowshoe hares (Lepus americanus), or in patches with intermediate densities of prey where lower stem densities and greater visibility promote increased mobility and access to prey. Lynx foraged within patches with intermediate to high hare density and intermediate cover for hares, and thus, attempted to maximize access to prey rather than exposure to habitats with highest prey density but optimal escape cover. Fractal dimension of movement paths was greater within preferred than in nonpreferred habitats and corresponded with higher foraging success in preferred habitats. Movement paths were more tortuous at broader than finer scales, suggesting that lynx were exhibiting stronger coarse-grained than fine-grained habitat preferences. Higher fractal dimension of movement paths reduced the number of transitions between patches of higher and lower foraging quality, resulting in individual movement patterns matching the scale of interpatch variation in hare abundance and accessibility within home ranges. Lynx made their strongest foraging decisions when exhibiting higher-order resource selection, so focusing conservation efforts to alter within-patch structure may be less effective than creating patch- and landscape-scale conditions that enhance foraging success. Coarse-grained resource selection by wide-ranging carnivores may reduce the importance of fine-scale conservation efforts and emphasizes the importance of focusing conservation for these coarse-grained species on factors influencing home-range quality and maintenance of viable landscapes. DOI: 10.1644/10-MAMM-A-005.1.

Does afforestation increase bird nest predation risk in surrounding farmland?

Afforestation of agricultural land is increasingly used to deliver environmental benefits, but their effects on biodiversity remain poorly understood. This paper tests the hypothesis that afforestation changes predation processes in surrounding farmland, examining how the characteristics and landscape context of forest plantations affect predator (birds and mammalian carnivores) and key prey (rabbits and hares) abundances, and bird nest predation rates in Iberian cereal-steppes. Lagomorphs and predators were surveyed in fallow fields around 50 forest plantations, where predation rates were estimated using artificial nests set at 0, 100, 200 and 300 m from the forest edge. Recent plantations structurally similar to sparse (oak) or dense (pine) shrublands were associated with the highest hare and rabbit abundances, respectively, whereas both species avoided landscapes with high eucalyptus cover. In contrast, mature eucalyptus plantations showed strong positive effects on typical nest predators such as corvids and carnivores. Open farmland fragmentation favoured the abundance of lagomorphs and carnivores. Despite these effects and the high predation rate on artificial nests (49%), there was neither evidence for increased predation near plantation edges nor higher predation in fields with more lagomorphs and predators. However, predation tended to increase with cover by young oak plantations and overall forest plantation cover, to decrease with eucalyptus cover at both the local and landscape scales, and to peak in landscapes with intermediate edge densities. These results suggest that afforestation may have strong effects on bird nest predation rates by changing landscape composition and configuration, rather than by inducing local increases in predator and prey populations. Nevertheless, increased abundances of generalist predators associated with forest plantations may still be considered of conservation concern, thus supporting the recommendation for strongly restricting afforestation in areas important for open grassland birds. Where this is unavoidable, monitoring should be undertaken to provide early signals for bird population declines associated with predator increases, eventually triggering conservation action such as predator exclusion or removal.

Top predators, mesopredators and their prey: interference ecosystems along bioclimatic productivity gradients

1. The Mesopredator Release Hypothesis (MRH) suggests that top predator suppression of mesopredators is a key ecosystem function with cascading impacts on herbivore prey, but it remains to be shown that this top-down cascade impacts the large-scale structure of ecosystems. 2. The Exploitation Ecosystems Hypothesis (EEH) predicts that regional ecosystem structures are determined by top-down exploitation and bottom-up productivity. In contrast to MRH, EEH assumes that interference among predators has a negligible impact on the structure of ecosystems with three trophic levels. 3. We use the recolonization of a top predator in a three-level boreal ecosystem as a natural experiment to test if large-scale biomass distributions and population trends support MRH. Inspired by EEH, we also test if top-down interference and bottom-up productivity impact regional ecosystem structures. 4. We use data from the Finnish Wildlife Triangle Scheme which has monitored top predator (lynx, Lynx lynx), mesopredator (red fox, Vulpes vulpes) and prey (mountain hare, Lepus timidus) abundance for 17 years in a 200 000 km(2) study area which covers a distinct productivity gradient. 5. Fox biomass was lower than expected from productivity where lynx biomass was high, whilst hare biomass was lower than expected from productivity where fox biomass was high. Hence, where interference controlled fox abundance, lynx had an indirect positive impact on hare abundance as predicted by MRH. The rates of change indicated that lynx expansion gradually suppressed fox biomass. 6. Lynx status caused shifts between ecosystem structures. In the 'interference ecosystem', lynx and hare biomass increased with productivity whilst fox biomass did not. In the 'mesopredator release ecosystem', fox biomass increased with productivity but hare biomass did not. Thus, biomass controlled top-down did not respond to changes in productivity. This fulfils a critical prediction of EEH. 7. We conclude that the cascade involving top predators, mesopredators and their prey can determine large-scale biomass distribution patterns and regional ecosystem structures. Hence, interference within trophic levels has to be taken into account to understand how terrestrial ecosystem structures are shaped.

Integrating field sports, hare population management and conservation

Conflicts between field sports, animal welfare and species conservation are frequently contentious. In Ireland, the Irish Coursing Club (ICC) competitively tests the speed and agility of two greyhounds by using a live hare as a lure. Each coursing club is associated with a number of discrete localities, known as preserves, which are managed favourably for hares including predator control, prohibition of other forms of hunting such as shooting and poaching and the maintenance and enhancement of suitable hare habitat. We indirectly tested the efficacy of such management by comparing hare abundance within preserves to that in the wider countryside. In real terms, mean hare density was 18 times higher, and after controlling for variance in habitat remained 3 times higher, within ICC preserves than the wider countryside. Whilst we cannot rule out the role of habitat, our results suggest that hare numbers are maintained at high levels in ICC preserves either because clubs select areas of high hare density and subsequently have a negligible effect on numbers or that active population management positively increases hare abundance. The Irish hare Lepus timidus hibernicus Bell, 1837 is one of the highest priority species for conservation action in Ireland and without concessions for its role in conservation, any change in the legal status of hare coursing under animal welfare grounds, may necessitate an increase in Government subsidies for conservation on private land together with a strengthened capacity for legislation enforcement.

Distribution and Abundance of Snowshoe Hares in Yellowstone National Park

Snowshoe hares (Lepus americanus) are widespread in boreal and montane forests of North America, vary in their temporal dynamics, and are major drivers in their food webs. In Yellowstone National Park, Wyoming, hare abundance, distribution, and temporal dynamics are unknown, yet Yellowstone contains a large area within their southern range that is relatively unfragmented by human activities. The 1988 Yellowstone fires have led to extensive regenerating stands, a seral condition that elsewhere supports relatively high numbers of hares. To examine snowshoe hare dynamics in the park from 2002 to 2007, we surveyed stands within 7 cover types and estimated abundance for a subset of sites. Both livetrapping data and fecal pellet count surveys showed that snowshoe hares are rare in Yellowstone. More than 36% of surveyed stands did not support any hares. Mature forest cover types were more likely to have hares than were stands regenerating after the 1988 fires, but very few stands supported high numbers; 96% of stands had ,0.5 hares/ha. Three stands that burned in 2003 had hares before the fire, but none afterward. Hare numbers fluctuated modestly over time, but patterns were not indicative of a cycle. Taken altogether, our results indicate that snowshoe hares in Yellowstone are rare, patchily distributed, and apparently acyclic, important findings both for understanding hare dynamics and for implications for the Yellowstone food web that includes the federally Threatened Canada lynx (Lynx canadensis).

Use of Residual Forest by Snowshoe Hare in a Clear-cut Boreal Landscape

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 ...

Predator abundance in relation to small game management in southern Portugal: conservation implications

The interaction between hunting interests and legally protected predators is often a contentious conservation problem, requiring detailed understanding of predator responses to game management. This issue was addressed in southern Portugal in a treatment-control natural experiment, whereby the abundances of small game, corvids, birds of prey and carnivores were compared in 12 game estates (>500 ha) and 12 matching areas with similar sizes and land uses but no game management. European rabbits (Oryctolagus cuniculus), Iberian hares (Lepus granatensis) and, less so, red-legged partridges (Alectoris rufa) were far more numerous in game estates than elsewhere. Among legally controlled species, there were less Eurasian jays (Garrulus glandarius) but more red foxes (Vulpes vulpes) in game estates, though the latter were primary targets of predator culling. Fox abundance within game estates varied inversely with an index of management intensity (density of small game feeding sites) and increased along with hare abundance. As for protected species, only common kestrels (Falco tinnunculus) and genets (Genetta genetta) were fewer in game estates. The abundance of raptors within game estates varied inversely with gamekeeper density, whereas that of common buzzards (Buteo buteo) increased along with rabbit abundance. Overall, there was little evidence that game management reduced local predator abundances, except in the most intensively managed estates. Game estates provided concentrations of prey that was scarce elsewhere, which may have favoured increased abundances of some predators. Further investigations are needed to find out whether high prey densities may attract predators to game estates with increased mortality risk, which may thus become population sinks for protected species.

Effects of carrion resources on herbivore spatial distribution are mediated by facultative scavengers

Carcasses of large herbivores are pulsed resources whose impact on animal communities and ecological processes is poorly understood. In temperate forests, long-lasting ungulate carcasses are a prime resource for many species of birds and mammals during winter. Facultative carrion-eaters also consume live prey, thus potentially leading to unexpected secondary effects on populations of species not directly linked to carcass exploitation. By snow-tracking and direct observations we investigated in Białowieża Forest (E. Poland) whether large ungulate carcasses elicit spatial responses in facultative scavengers and their prey. We found that in the vicinity of carcass sites the probability of the presence of common ravens Corvus corax, jays Garrulus glandarius and red foxes Vulpes vulpes increased significantly. Indeed, large groups of the two bird species were exclusively found in those places. Because of these aggregations, the probability of predator–prey encounters (red foxes and brown hares Lepus europaeus) was significantly higher near carcass sites. Accordingly, the abundance of hares and other live prey such as red squirrels Sciurus vulgaris decreased at their vicinities, probably as a consequence of direct killing and/or predator avoidance. This study provides the first evidence of carrion pulses permeating into apparently distant trophic levels, such as herbivores, via facultative scavengers, thus highlighting some unnoticed but relevant effects of carrion resources on community structure. Die Kadaver von großen Herbivoren sind kurzfristige Ressourcen, deren Auswirkungen auf Tiergemeinschaften und ökologische Prozesse nur wenig verstanden sind. In gemäßigten Wäldern sind während des Winters sich lange haltende Kadaver von Huftieren eine primäre Ressource für viele Arten von Vögeln und Säugetieren. Fakultative Aasfresser fressen auch lebende Beute und es kann daher zu unerwarteten sekundären Effekten auf Populationen von Arten kommen, die nicht direkt mit der Aasnutzung verbunden sind. Über Fährtensuche im Schnee und direkte Beobachtungen im Wald von Białowieża (Ostpolen) untersuchten wir, ob die Kadaver von groβen Huftieren räumliche Reaktionen bei fakultativen Aasfressern und ihren Beutetieren auslösten. Wir fanden, dass in der Nachbarschaft von Kadavern Kolkraben Corvus corax, Eichelhäher Garrulus glandarius und Rotfüchse Vulpes vulpes mit signifikant größerer Wahrscheinlichkeit anwesend waren. Tatsächlich wurden große Ansammlungen der beiden Vogelarten ausschließlich in der Nähe dieser Plätze gefunden. Aufgrund dieser Aggregationen war die Wahrscheinlichkeit für die Begegnung von Räuber und Beute (Rotfuchs und Hase Lepus europaeus) in der Nähe von Kadavern signifikant höher. Als Folge nahm die Häufigkeit von Hasen und anderer lebender Beute wie dem Eichhörnchen Sciurus vulgaris in der Nachbarschaft ab, entweder aufgrund von Tötungen oder Räubervermeidung. Diese Untersuchung liefert den ersten Beweis dafür, dass sich ein Impuls durch einen Kadaver in offensichtlich entfernte trophische Ebenen, wie z. B. Herbivore, durch fakultative Aasfresser fortsetzt, und zeigt so einige wenig beachtete aber wichtige Auswirkungen einer Aasressource auf die Gemeinschaftsstrukur.

Interlinking hare and lynx dynamics using a century's worth of annual data

AbstractThe classic fur trade records on Canadian lynx (Lynx canadensis) have rarely been analysed in direct conjunction with data on its principal prey, the snowshoe hare (Lepus americanus). Comparable long‐term data for hare exist only for a region south of Hudson Bay. We fitted a bivariate log‐linear time‐series model to this hare and lynx data to disentangle the within‐ and between‐population interactions of these species. To reduce problems with fur returns being non‐normal and non‐linearly related to abundance, we transformed the fur returns to a normal distribution based on sample quantiles. The estimated effect on next year's lynx abundance of a 1% increase in current hare abundance was a 0.23% (SE = 0.05) increase in lynx. Conversely, a 1% increase in current lynx abundance corresponded to a 0.46% (SE = 0.12) decrease in next year's hare abundance. This contrasts with some earlier studies. However, these studies mixed hare data from south of Hudson Bay with lynx totals for all of Canada. Despite this asymmetry of interaction strengths, coefficients of determination were similar for hare versus lynx and lynx versus hare, because hare abundance varies more than lynx. Both species showed clear intraspecific density‐dependence of about equal strength. A 1% increase in current abundance increased next year's abundance by about 0.75%.

Effects of roads on spatial distribution, abundance and mortality of brown hare (Lepus europaeus) in Switzerland

Brown hare populations (Lepus europaeus) are in decline throughout Europe since the 1960s, and numerous impact factors have been discussed in the literature. Although landscape fragmentation by roads is assumed to be one potential factor, the effects of roads on brown hare populations are poorly understood. We studied three potential effects of roads on brown hares asking: (1) Do roads affect the spatial distribution of hares due to disturbance effects? (2) Does road network density affect hare abundance due to barrier effects? (3) Does road network density affect road mortality rates in hare populations? The study is based on harvest statistics and spotlight taxations in Canton Aargau, Switzerland and was conducted at three different spatial scales. Spatial distribution was studied in plots established in varying distances parallel to roads, effects on abundance were analysed on the basis of raster grids, and road mortality was studied on the level of hunting districts. We show that (1) hares avoid the proximity to roads and prefer large non-fragmented areas over small isolated patches. (2) The density of freeways, federal and main roads has a negative effect on hare abundance. The density of unpaved field tracks has a positive effect probably because vegetation at field tracks contributes to the diet spectrum. (3) Effects of road network density on road mortality rates could not be shown, although road mortality has increased since the 1990s. We conclude that in debilitated populations, roads act as threatening factor for brown hare. We recommend establishing large un-dissected areas as a new category of wildlife refuge and to protect these areas from being further fragmented.

Diurnal Habitat Relationships of Canada Lynx in an Intensively Managed Private Forest Landscape in Northern Maine

In March 2000, Canada lynx (Lynx canadensis) were listed as a federally threatened species in 14 states at the southern periphery of their range, where lynx habitat is disjunct and snowshoe hare (Lepus americanus) densities are low. Forest conditions vary across lynx range; thus, region-specific data on the habitat requirements of lynx are needed. We studied lynx in northern Maine, USA, from 1999 to 2004 to assess quality and potential for forests in Maine to sustain lynx populations. We trapped and radiocollared 43 lynx (21 M, 22 F) during this period and evaluated diurnal habitat selection by 16 resident adult lynx (9 M, 7 F) monitored in 2002. We evaluated lynx selection of 8 habitats at multiple spatial scales, and related lynx habitat selection to snowshoe hare abundance. Lynx preferred conifer-dominated sapling stands, which supported the highest hare densities on our study site (x̄ = 2.4 hares/ha), over all other habitats. The habitats where lynx placed their home ranges did not differ by sex. However, within their home ranges, males not only preferred conifer-dominated sapling stands, but also preferred mature conifer, whereas females singularly preferred conifer-dominated sapling stands. Approximately one-third of Maine's spruce–fir forest and nearly 50% of our study area was regenerating conifer or mixed-sapling forest, resulting from a disease event and intensive forest management (e.g., large clear-cuts). Our findings suggest that current habitat conditions in Maine are better than western montane regions and approach conditions in boreal forests during periods of hare abundance. We recommend that forest landowners maintain a mosaic of different-aged conifer stands to ensure a component of regenerating conifer-dominated forest on the landscape.

A Large-scale Survey of Brown Hare Lepus Europaeus and Iberian Hare L. Granatensis Populations at the Limit of Their Ranges

The historical ranges of the European brown hare Lepus europaeus and the Iberian hare L. granatensis meet in Aragon in northeastern Spain. We studied the relative abundances and the population trends of the two species in 60 localities (13 for the brown hare, 38 for the Iberian hare, and nine from the transition zone where both species are present) by spotlighting in winter during 1992-2002. We carried out a total of 1,407 counts covering 41,511 km. Both the Iberian (132.2 6 33.2 hares/100 km; range: 52-192) and the brown hare (106.7 6 26.8; range: 53-136) were more abundant in their respective zones than both species combined in the transition zone (90.9 6 50.5, range: 37-157). The highest Iberian hare abundances were recorded in the northern Iberian Mountains, an area with well-preserved cereal-dominated ecosystems and a less extreme cli- mate than in other parts of the study area. The Iberian hare had signifi- cant inter-annual differences both locally and generally, which was main- ly due to a peak in 1998, and this species showed a general positive trend during the study period, suggesting that Iberian hare numbers are in- creasing. Contrary to the marked declines reported from other European regions, the brown hare abundance indices obtained in the Spanish Pyr- enees during our study period remained stable.

DNA Markers for Identifying Individual Snowshoe Hares Using Field-collected Pellets

Snowshoe hare (Lepus americanus) abundance has been of interest to wildlife biologists, as hares are essential prey items for many rare and endangered predators. Snowshoe hare abundance has most commonly been estimated through indices such as pellet counts. While pellet counts may be useful in the areas they are developed and when hares are dense, they notably fail when hares are at low densities. Abundance estimates using capture-mark-recapture (CMR) are often preferred over indices of animal abundance, yet using CMR to estimate snowshoe hare numbers has proven a formidable and expensive task. Sample sizes obtained using traditional CMR techniques are frequently low, resulting in either biased estimates or estimates with unacceptably high variance. Here we derive a suite of 9 microsatellite DNA markers that can provide snowshoe hare individual identification at relatively low cost. We demonstrate that these markers produce no genotyping errors in a captive situation and use the markers to produce individual identification of free-ranging snowshoe hares in test plots in Montana and Idaho.

Do mountain hare populations cycle?

We investigated the occurrence and distribution of multi‐annual cycles in abundance of mountain hare populations across a wide area of their range in northern Europe. We analysed 125 time‐series of mountain hare abundance indexed from hunting bag records and questionnaire responses from Scotland, Sweden, Finland and Switzerland. We also reanalysed 17 previously published time‐series based on hunting bag records and snow track indices from mountain hare populations in Scotland, Norway, Sweden, Finland, Russia and Italy. Autocorrelation analysis showed that 45% of mountain hare populations showed evidence of cycles, characterised by significant negative autocorrelations at half or the whole cycle period. The amplitude and periodicity of cycles varied between and within countries. Time‐series in Scotland were characterised by high‐amplitude weak cycles with a mean periodicity of nine years but with a range of 4–15 years. Norwegian and Swedish time‐series revealed low amplitude weak cycles with a 3–7 year period. Finnish time‐series showed low amplitude cycles with a 4–11 year period. Alpine time‐series were predominantly non‐cyclic, while the limited number of series from Russia showed high amplitude weak cycles with an 8–11 year period. The results reveal that mountain hare populations show a wide range of population dynamics with distinct regional differences in periodicity, amplitude and density dependent structure of cycles. These findings suggest that different factors may limit or regulate mountain hare populations in different regions of Europe thus supporting the results of recent field studies.

Winter Habitat Selection by Canada Lynx in Maine: Prey Abundance or Accessibility?

Abstract:We related winter habitat selection by Canada lynx (Lynx canadensis), relative abundance of snowshoe hares (Lepus americanus), and understory stem densities to evaluate whether lynx select stands with the greatest snowshoe hare densities or the greatest prey accessibility. Lynx (3 F, 3 M) selected tall (4.4‐7.3 m) regenerating clear‐cuts (11‐26 yr postharvest) and established partially harvested stands (11‐21 yr postharvest) and selected against short (3.4‐4.3 m) regenerating clear‐cuts, recent partially harvested stands (1‐10 yr), mature second‐growth stands (>40 yr), and roads and their edges (30 m on either side of roads). Lynx selected stands that provided intermediate to high hare density and intermediate cover for hares (i.e., prey access) but exhibited lower relative preference for stand types with highest hare densities where coniferous saplings exceeded 14,000 stems/ha.

Is Size of Fecal Pellets a Reliable Indicator of Species of Leporids in the Southern Rocky Mountains?

Abstract: In the southern Rocky Mountains, USA, snowshoe hares (Lepus americanus) and mountain cottontails (Sylvilagus nuttallii) are syntopic. Previous researchers used size of fecal pellets to identify leporid species in the Southern Rockies, a common criterion for identifying species of cervids. We measured 655 fecal pellets from 10 mountain cottontails and 2,374 fecal pellets from 23 snowshoe hares. We found no relationship between the body weight of mountain cottontails and the size of their fecal pellets (r = 0.04, F = 0.01, P = 0.91) but found one for snowshoe hares (r = 0.48, F = 9.3, P = 0.005). Although the 2 species differed in the size of their fecal pellets, the difference between means (1.2 mm) was sufficiently small to require measuring individual pellets and is only applicable to individuals of adult size. Although fecal pellet counts may be used to estimate presence and relative abundance of snowshoe hares in the absence of syntopic leporids, where multiple species of leporids are syntopic this method may yield misleading results.

Can Reindeer Overabundance Cause a Trophic Cascade?

The region Finnmark, in northernmost Europe, harbors dense populations of semi-domestic reindeer of which some exhibit characteristics of overabundance. Whereas overabundance is evident in terms of density-dependent reductions in reindeer body mass, population growth and abundance of forage plants, claims have been made that this reindeer overabundance also has caused a trophic cascade. These claims are based on the main premise that reindeer overgrazing negatively impacts small-sized, keystone tundra herbivores. We tested this premise by a large-scale study in which the abundance of small rodents, hares and ptarmigans was indexed across reindeer management districts with strong differences in stocking densities. We examined the scale-dependent relations between reindeer, vegetation and these small-sized herbivores by employing a spatially hierarchical sampling design within the management districts. A negative impact of reindeer on ptarmigan, probably as a result of browsing reducing tall Salix, was indicated. However, small rodents (voles and lemmings), which are usually the keystone herbivores in the plant-based tundra food web, were not negatively impacted. On the contrary, there was a strong positive relationship between small rodents and reindeer, both at the scale of landscape areas and local patches, with characteristics of snow-bed vegetation, suggesting facilitation between Norwegian lemmings and reindeer. We conclude that the recent dampening of the vole and lemming population cycle with concurrent declines of rodent predators in northernmost Europe were not caused by large herbivore overgrazing.