Wolf-Pack Buffer Zones as Prey Reservoirs

“Avoidance among wolf packs creates buffer zones where ungulates may aggregate (Mech 1977, Lewis and Murray 1993).”

“For example, in a wolf–ungulate system, ungulates may seek refuge by migrating to areas outside the core territories of wolves (migration) or survive longer outside the wolves’ core use areas (mortality) (Mech 1977).”

“For example, deer are known to keep to the periphery of wolf territories (Hoskinson & Mech 1976; Mech 1977) and re- duce their feeding effort when exposed to odors of wolves and other predator species (Muller-Schwarze 1972; Sullivan et al. 1985).”

“When wolves were present, ungulate antipredator strategies may have included the avoidance of high wolf use areas (Mech, 1977; Roby, 1978; Allen, 1979; Edwards, 1983; Ferguson et al., 1988).”

“Hunting grounds of the NR are used by multiple wolf packs, a situation that does not conform to the widely held conceptual model of distinct territorial boundaries with interstitial prey refuges that has been suggested on an empirical (Mech 1977) and theoretical (Lewis & Murray 1993) basis.”

“…a shift in habitat use when ungulates are faced with predation pressures from large predators such as wolves Canis lupus and pumas Puma concolor (Mech 1977, Edwards 1983, Stephens & Peterson 1984, Altendorf et al. 2001), and evidence of reduced diet quality has also been presented (Edwards…”

“In areas where pack boundaries overlapped within a season and year, we assigned the lower RSF value to that pixel because of probable decreased vigilance by pack members in those areas and, subsequently, lower predation risk (Mech 1977, Rogers et al. 1980, Mech 1994).”

“Wildlife biologists have found merit in Hickerson’s war zone hypothesis and employed it in modified form to account for deer survival in a “no-wolves’ land” between territories of adjoining packs (Mech 1977).”

“The importance of space division between predators and prey was recently confirmed by an interesting field study on wolves and deer (Mech 1977).”

“The presence of un-collared wolf packs adjacent to the study area might influence direct predation risk measures in peripheral quadrats; however, there tends to be an unoccupied ‘‘noman’s land’’ between neighbouring packs which should minimize this potential impact (Mech 1977).”

“Given that all signals from local patches suggest foraging returns were declining across the entire occupational history of the mound, could the resurgence in deer use be reecting the increasing use of less-depleted deer patches located in the oak woodlands that extend far to the east of the site? Such distant patche…”

“It follows that, competition for food should be less pronounced in areas where individuals overlap, such that fewer prey would be killed in those areas than would be expected based on the availability of resources (Mech, 1977; Pierce et al., 2000).”

“As wolf packs tend to avoid intensive use of buffer zones, deer inhabiting those areas are predicted to experience lower predation pressure [66] and numbers can become higher at boundaries of wolf packs compared to the territory centers [66,67].”

“Wolf buffer zones have been found to have higher deer survivorship (Hoskinson and Mech 1976; Mech 1977; Rogers et al. 1980; Lewis and Murray 1993) and provide refuge for coyotes (Berg and Chesness 1978; Fuller and Keith 1981; Arjo and Pletscher 1999).”

“keeping to the periphery of wolf territories (Hoskinson and Mech, 1976; Mech, 1977).”

“Third, if hostile interactions with neighboring groups involve a high risk of injury, this could lead to avoidance of overlap areas (Hickerson, 1965, 1970; Mech, 1977; Kelly, 2005).”

“Prey refugia are essential to the maintainance of many predator-prey systems, such as the wolf and deer ( Mech, 1977 ).”

“Spatial heterogeneity in predation risk creates spatial refugia that can be potentially exploited by prey and consequently lower predator efficiency (Mech 1977; Fontaine & Martin 2006; Schmidt, Ostfeld & Smyth 2006; Schauber et al. 2009).”

“A similar example is played out by whitetailed deer (Odocoileus virginianus) that occupy gaps that exist between adjacent wolf (Canis lupus) packs (Mech 1977; Lewis and Murray 1993).”

“The overlapping edges between pack territories, which are generally avoided by wolves, have also been shown to be have higher deer densities (Mech, 1977).”

“Wolves are less likely to hunt in these buffer zones so as to avoid potentially fatal encounters with neighbouring wolf packs (Mech 1977).”

“…one might expect the moose cows to show anti-predator adaptations such as altered behavior and habitat use, as found in North American studies of wolf-ungulate relationships (Mech 1966, 1977; Peterson 1977; Edwards 1983; Stephens and Peterson 1984; Berger et al. 2001; Laundré et al. 2001).”

“White-tailed deer (Odocoileus virginianus; Mech 1977), elk (Cervus elaphus; Fortin et al. 2005), and coyotes (Arjo and Pletcher 1999) minimize risk of predation by avoiding areas used by wolves.”

“There are also sites visited disproportionally less frequently than others, such as territory overlaps of neighboring gray wolf packs, which were previously identified as providing naturally safe areas for wild ungulates (46).”

“However, territoriality is a common social behavior that can have large impacts on the distribution of herbivores and their prey by creating refuges along the peripheries of adjacent territories (Mech 1977, Robertson 1989).”

“Keywords: historical ecology, Lewis and Clark, wildlife distribution, buffer zones, predation October 2003 / Vol. 53 No. 10 • BioScience 995 along the edges of wolf territories; wolves avoided those zones to reduce encounters with the neighboring packs (Mech 1977).”

“Methods in Ecology and Evolution © 2013 British Ecological Society, Methods in Ecology and Evolution, 4, 276–289 case they owe much to the territorial behaviour of predators Mech, 1977;Moorcroft &Lewis, 2006).”

“The data generally support the hypotheses that deer densities tend to he greater along wolf pack territory buffer zones than in territory centers (Hoskinson and Mech 1976; Mech 1977a,b; Nelson and Mech, unpubl. data).”

“However, urine is an important mode of chemical communication for the wolf (Peters and Mech, 1975; Mech, 1977).”

“, deer herds occupying areas at the boundaries of wolf pack territories (Mech 1977; Rogers, et aI., 1980, Nelson and Mech 1981), ii) biochemical separation, e.”

“…safe havens for prey species that may generate source-sink dynamics at the population level, e.g., wolf (Canis lupus) and white-tailed deer (Odocoileus virginianus) populations (Mech 1977; Mech et al. 1980) and chimpanzee (Pan troglodytes) and red colobus monkey (Colobus badius) (Stanford 1995).”

“Countering these tests by predators, ungulates have developed antipredator strategies and behaviors (Mech 1977; Geist 1982; Estes 1991; Nelson and Mech 1991).”

“individual movements, wolf sociality has been shown to create areas between pack home ranges where space use is orders of magnitude lower, deer survivorship is higher and rates of herbivory are much greater (Mech 1977; Lewis and Murray 1993).”

“We plotted these locations from October 1 through March 30 and April 1 through September 30 each year, and used minimum convex polygons (MCPs; Mohr 1947) to represent territories (Mech 1973, 1977b, 1986) .”

“Likewise, Mech (1977) 178 noted that wolves form stable territories that are separated by buffer zones up to 2 km wide, into 179 which wolves rarely venture to avoid antagonistic interactions with neighboring packs.”

“This should equally be expected in territorial mammalian predators that have dens, such as in canids where a negative spatial correlation with their ungulate prey has previously been observed [30] and confirmed by modeling [31].”

“Previous research has shown that wolf territories often overlap (Van Ballenberghe et al. 1975 ; Peterson 1977 ; Fritts and Mech 1981 ; Nelson and Mech 1981 ; Peterson et al. 1984 ; Jeþdrzejewski et al. 2007) . This tendency also occurred in northwestern Wisconsin and east-central Minnesota (Gehring 1995 ; Shelley and…”

“Wolves usually have higher risks of fatal encounters in the edges of their territories because in these “buffer zones” the chance to find a member of a neighborhood wolf pack is higher and these situations can lead to lethal competition interactions for territory (Mech 1977; Mech, 1994).”

“2010), are often forced to use safer habitats with poorer forage instead of riskier habitats with richer forage (Mech 1977; Edwards 1983; Altendorf et al.”