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Geology topics

L. David Mech

Publications and source records attributed to L. David Mech.

At least 73 records · Page 4Linked to original sources
USGS2013

The challenge of wolf recovery: an ongoing dilemma for state managers

“Dave, would you do another legal declaration on the wolf for us?” The weary voice on the phone belonged to Mike Jimenez, Northern Rocky Mountain Wolf Management and Science Coordinator for the U.S. Fish and Wildlife Service (FWS). He was calling from Wyoming to ask me to prepare a document to address a legal challenge to the FWS’s August 2012 delisting of the wolf (Canis lupus) in Wyoming, a highly controversial move. Mike’s tone reflected the reality that — as so many wildlife biologists know and live each day — wildlife management is mainly people management. This contention could not be truer for managing any wildlife species than for managing the wolf. Dubbed “the beast of waste and desolation” by Teddy Roosevelt (The Wilderness Hunter 1893/1900), wolves had been universally hated as prolific predators of valuable livestock and game. Around the turn of the 20th century, members of the U.S. Biological Survey and various state agents, ranchers, cowboys, and other frontiersmen poisoned and persecuted wolves, extirpating them from most of the contiguous United States (Young and Goldman 1944). By 1967, Minnesota and nearby Isle Royale National Park in Michigan held the only remaining wolves in the Lower 48 states, prompting the FWS to place the wolf on the Endangered Species List (established by the Endangered Species Preservation Act of 1966). The wolf then became the list’s poster species, and the timing was ideal: Silent Spring (Carson 1962) had just seeded and fertilized the environmental movement, which blossomed on Earth Day (April 22, 1970) into the environmental revolution. “Save the wolf!” became one of the movement’s rallying cries. And save the wolf we did.

The Wildlife Professional↗
USGS2013

How not to find a wolf den

A five-day odyssey, spanning 58 hours without decent sleep or meals, taught these researchers one thing-how not to find a wolf den.

International Wolf↗
USGS2013

Brutus

Explore the source record for details and available documents.

Book chapter↗
USGS2013

Minnesota wolf 2407: a research pioneer

The International Wolf Center has assembled in this book stories from over 30 wolf biologists from throughout North America and Europe. These tales provide a glimpse into the amazing lives of individual wolves, revealing their unique personalities, highlighting their struggles and triumphs, and illustrating the unique influence the individual can have on the survival of its pack and the population to which it belongs.

Book chapter↗
USGS2013

The case for watchful waiting with Isle Royale's wolf population

In "Should Isle Royale Wolves be Reintroduced? A Case Study on Wilderness Management in a Changing World," Vucetich et al. concluded with the hope that their analysis “motivates broader discussion that deepens understanding of the specifics on Isle Royale and the underlying principles” (2012: 137). This article represents an attempt to continue that discussion.

The George Wright Forum↗
USGS2012

Gray Wolf (Canis lupus) movements and behavior around a kill site and implications for GPS collar studies

Global Positioning System (GPS) radio-collars are increasingly used to estimate Gray Wolf ( Canis lupus ) kill rates. In interpreting results from this technology, researchers make various assumptions about wolf behavior around kills, yet no detailed description of this behavior has been published. This article describes the behavior of six wolves in an area of constant daylight during 30 hours, from when the pack killed a Muskox ( Ovibos moschatus ) calf and yearling on Ellesmere Island, Nunavut, Canada, to when they abandoned the kill remains. Although this is only a single incident, it demonstrates one possible scenario of pack behavior around a kill. Combined with the literature, this observation supports placing a radio-collar on the breeding male to maximize finding kills via GPS collars and qualifying results depending on whatever other information is available about the collared wolf’s pack.

Ellesmere Island, Nunavut↗
USGS2012

Is science in danger of sanctifying the wolf?

Historically the wolf ( Canis lupus ) was hated and extirpated from most of the contiguous United States. The federal Endangered Species Act fostered wolf protection and reintroduction which improved the species' image. Wolf populations reached biological recovery in the Northern Rocky Mountains and upper Midwest, and the animal has been delisted from the Endangered Species List in those areas. Numerous studies in National Parks suggest that wolves, through trophic cascades, have caused ecosystems to change in ways many people consider positive. Several studies have been conducted in Yellowstone National Park where wolf interactions with their prey, primarily elk ( Cervus elaphus ), are thought to have caused reduction of numbers or changes in movements and behavior. Some workers consider the latter changes to have led to a behaviorally-mediated trophic cascade. Either the elk reduction or the behavioral changes are hypothesized to have fostered growth in browse, primarily willows ( Salix spp.) and aspen ( Populus spp.), and that growth has resulted in increased beavers ( Castor Canadensis ), songbirds, and hydrologic changes. The wolf's image thus has gained an iconic cachet. However, later research challenges several earlier studies' findings such that earlier conclusions are now controversial; especially those related to causes of browse regrowth. In any case, any such cascading effects of wolves found in National Parks would have little relevance to most of the wolf range because of overriding anthropogenic influences there on wolves, prey, vegetation, and other parts of the food web. The wolf is neither a saint nor a sinner except to those who want to make it so.

Biological Conservation↗
USGS2012

Use of real-time PCR to detect canine parvovirus in feces of free-ranging wolves

Using real-time PCR, we tested 15 wolf ( Canis lupus ) feces from the Superior National Forest (SNF), Minnesota, USA, and 191 from Yellowstone National Park (YNP), USA, collected during summer and 13 during winter for canine parvovirus (CPV)-2 DNA. We also tested 20 dog feces for CPV-2 DNA. The PCR assay was 100% sensitive and specific with a minimum detection threshold of 10 4 50% tissue culture infective dose. Virus was detected in two winter specimens but none of the summer specimens. We suggest applying the technique more broadly especially with winter feces.

Minnesota, Wyoming↗
USGS2011

Movements of wolves at the northern extreme of the species' range, including during four months of darkness

Information about wolf ( Canis lupus ) movements anywhere near the northern extreme of the species' range in the High Arctic (>75°N latitude) are lacking. There, wolves prey primarily on muskoxen ( Ovibos moschatus ) and must survive 4 months of 24 hr/day winter darkness and temperatures reaching -53 C. The extent to which wolves remain active and prey on muskoxen during the dark period are unknown, for the closest area where information is available about winter wolf movements is >2,250 km south. We studied a pack of ≥20 wolves on Ellesmere Island, Nunavut, Canada (80°N latitude) from July 2009 through mid-April 2010 by collaring a lead wolf with a Global Positioning System (GPS)/Argos radio collar. The collar recorded the wolf's precise locations at 6:00 a.m. and 6:00 p.m. daily and transmitted the locations by satellite to our email. Straight-line distances between consecutive 12-hr locations varied between 0 and 76 km. Mean (SE) linear distance between consecutive locations (n = 554) was 11 (0.5) km. Total minimum distance traveled was 5,979 km, and total area covered was 6,640 km 2 , the largest wolf range reported. The wolf and presumably his pack once made a 263-km (straight-line distance) foray to the southeast during 19–28 January 2010, returning 29 January to 1 February at an average of 41 km/day straight-line distances between 12-hr locations. This study produced the first detailed movement information about any large mammal in the High Arctic, and the average movements during the dark period did not differ from those afterwards. Wolf movements during the dark period in the highest latitudes match those of the other seasons and generally those of wolves in lower latitudes, and, at least with the gross movements measurable by our methods, the 4-month period without direct sunlight produced little change in movements.

Ellesmere Island;Nunavut↗
USGS2011

Nonlinear effects of group size on the success of wolves hunting elk

Despite the popular view that social predators live in groups because group hunting facilitates prey capture, the apparent tendency for hunting success to peak at small group sizes suggests that the formation of large groups is unrelated to prey capture. Few empirical studies, however, have tested for nonlinear relationships between hunting success and group size, and none have demonstrated why success trails off after peaking. Here, we use a unique dataset of observations of individually known wolves ( Canis lupus ) hunting elk ( Cervus elaphus ) in Yellowstone National Park to show that the relationship between success and group size is indeed nonlinear and that individuals withholding effort (free riding) is why success does not increase across large group sizes. Beyond 4 wolves, hunting success leveled off, and individual performance (a measure of effort) decreased for reasons unrelated to interference from inept hunters, individual age, or size. But performance did drop faster among wolves with an incentive to hold back, i.e., nonbreeders with no dependent offspring, those performing dangerous predatory tasks, i.e., grabbing and restraining prey, and those in groups of proficient hunters. These results suggest that decreasing performance was free riding and that was why success leveled off in groups with >4 wolves that had superficially appeared to be cooperating. This is the first direct evidence that nonlinear trends in group hunting success reflect a switch from cooperation to free riding. It also highlights how hunting success per se is unlikely to promote formation and maintenance of large groups.

Behavioral Ecology↗
USGS2011

Wolves, Canis lupus, carry and cache the collars of radio-collared White-tailed Deer, Odocoileus virginianus, they killed

Wolves ( Canis lupus ) in northeastern Minnesota cached six radio-collars (four in winter, two in spring-summer) of 202 radio-collared White-tailed Deer ( Odocoileus virginianus ) they killed or consumed from 1975 to 2010. A Wolf bedded on top of one collar cached in snow. We found one collar each at a Wolf den and Wolf rendezvous site, 2.5 km and 0.5 km respectively, from each deer's previous locations.

Minnesota↗
USGS2011

Use of cranial characters in taxonomy of the Minnesota wolf ( Canis sp.)

Minnesota wolves ( Canis sp.) sometimes are reported to have affinity to a small, narrow-skulled eastern form ( Canis lupus lycaon Schreber, 1775) and sometimes to a larger, broader western form ( Canis lupus nubilus Say, 1823). We found that pre-1950 Minnesota wolf skulls were similar in size to those of wolves from southeastern Ontario and smaller than those of western wolves. However, Minnesota wolf skulls during 1970–1976 showed a shift to the larger, western form. Although Minnesota skull measurements after 1976 were unavailable, rostral ratios from 1969 through 1999 were consistent with hybridization between the smaller eastern wolf and the western form. Our findings help resolve the different taxonomic interpretations of Minnesota skull morphology and are consistent with molecular evidence of recent hybridization or intergradation of the two forms of wolves in Minnesota. Together these data indicate that eastern- and western-type wolves historically mixed and hybridized in Minnesota and continue to do so. Our findings are relevant to a recent government proposal to delist wolves from the endangered species list in Minnesota and surrounding states.

Minnesota↗
USGS2011

Non-genetic data supporting genetic evidence for the eastern wolf

Two schools of thought dominate the molecular-genetics literature on Canis spp. (wolves) in the western Great Lakes region of the US and Canada: (1) they are hybrids between Canis lupus (Gray Wolf) and Canis latrans (Coyote), or (2) they are hybrids between the Gray Wolf and Canis lycaon (Eastern Wolf). This article presents 3 types of non-genetic evidence that bears on the controversy and concludes that all 3 support the second interpretation.

Great Lakes Region↗
USGS2011

Accuracy of estimating wolf summer territories by daytime locations

We used locations of 6 wolves ( Canis lupus ) in Minnesota from Global Positioning System (GPS) collars to compare day-versus-night locations to estimate territory size and location during summer. We employed both minimum convex polygon (MCP) and fixed kernel (FK) methods. We used two methods to partition GPS locations for day-versus-night home-range comparisons: (1) daytime = 0800–2000 h; nighttime = 2000–0800 h; and (2) sunup versus sundown. Regardless of location-partitioning method, mean area of daytime MCPs did not differ significantly from nighttime MCPs. Similarly, mean area of daytime FKs (95% probability contour) were not significantly different from nightime FKs. FK core use areas (50% probability contour) did not differ between daytime and nighttime nor between sunup and sundown locations. We conclude that in areas similar to our study area day-only locations are adequate for describing the location, extent and core use areas of summer wolf territories by both MCP and FK methods.

Minnesota↗
USGS2011

Parsing demographic effects of canine parvovirus on a Minnesota wolf population

We examined 35 years of relationships among wolf ( Canis lupus ) pup survival, population change and canine parvovirus (CPV) seroprevalence in Northeastern Minnesota to determine when CPV exerted its strongest effects. Using correlation analysis of data from five periods of 7-years each from 1973 through 2007, we learned that the strongest effect of CPV on pup survival ( r = -0.73) and on wolf population change ( r = -0.92) was during 1987 to 1993. After that, little effect was documented despite a mean CPV seroprevalence from 1994 of 2007 of 70.8% compared with 52.6% during 1987 to 1993. We conclude that after CPV became endemic and produced its peak effect on the study population, that population developed enough immunity to withstand the disease.

Minnesota↗
USGS2011

Minnesota wolf ear lengths as possible indicators of taxonomic differences

Genetic findings suggest that 2 types of wolves, Canis lupus (Gray Wolf) and C. lycaon (Eastern Wolf), and/or their hybrids occupy Minnesota (MN), and this study examines adult wolf ear lengths as a possible distinguisher between these two. Photographic evidence suggested that the Eastern Wolf possesses proportionately longer ears than Gray Wolves. Ear lengths from 22 northwestern MN wolves from the early 1970s and 22 Alaskan wolves were used to represent Gray Wolves, and the greatest length of the sample (12.8 cm) was used as the least length to demarcate Eastern Wolf from Gray Wolf influence in the samples. Twenty-three percent of 112 adult wolves from Algonquin Park in eastern Ontario and 30% of 106 recent adult wolves in northeastern MN possessed ears >12.8 cm. The northeastern MN sample differed significantly from that of current and past northwestern MN wolves. Ear-lengths of wolves in the eastern half of the northeastern MN wolf population were significantly longer than those in the western half of that study area, even though the mean distance between the 2 areas was only 40 km, and the mean length of my 2004–2009 sample was significantly longer than that of 1999–2003. These findings support the hypothesis that Eastern Wolves tend to possess longer ears than do Gray Wolves and suggest a dynamic hybridization process is still underway in MN.

Minnesota↗