wolves wolves are endangered or extirpated in many parts of their (former) range. the gray wolf,...

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Wolves •Wolves are endangered or extirpated in many parts of their (former) range. •The gray wolf, Canis lupus, had a range in North America from the arctic to central Mexico. •In the old world, gray wolves ranged from arctic Siberia and Scandinavia to the deserts of Israel, and were once common in the forests of Europe. •Also in the old world, most populations outside of northern China and Siberia are small and isolated.

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Wolves

•Wolves are endangered or extirpated in many parts of their (former) range. •The gray wolf, Canis lupus, had a range in North America from the arctic to central Mexico. •In the old world, gray wolves ranged from arctic Siberia and Scandinavia to the deserts of Israel, and were once common in the forests of Europe. •Also in the old world, most populations outside of northern China and Siberia are small and isolated.

A little basic wolf biology• Wolves are social animals, usually grouped in packs,

which consist of a set of behaviourally dominant parents (the s), their offspring of the last few years, and other non-breeding adults, which have been accepted into the pack, but are unrelated.

• Bond between paired dominant animals may be for life• The age of first reproduction is generally about 2-3 years.

The average litter is about 6 pups.• Pups are weaned between 2 - 3 months. • By 7-8 months they hunt with their parents• At 1-2 years, males may leave their pack and attempt to

form a new one on their own, or they may remain with their family pack

• Males are the ones forming packs, but they may take females with them.

• Wolf packs have established territories. The size varies from about 128 to 2560 km2.

• Wolves may move up to 50 km in a day.• They establish the boundaries of territories by scent

marking. • Other pack(s) may temporarily use a portion of competitor

pack’s territory• Wolf packs establish their presence even without recent

marking by howling at night. Howling may also locate other members of the pack temporarily separated, sound an alarm etc.

• Other predatory species are supported by wolf kills, including ravens, foxes, vultures, wolverines and eagles.

Recent population estimates:• 520 in Michigan• 537 in Wisconsin• 1600 in Montana, Idaho, Wyoming• 5900-7200 in Alaska • 6300 in 1980 in British Columbia• 4000-5000 in Alberta • For the U.S. these recent estimates contrast with the lows

reached during the 1950s, when the total population of grey wolves had declined to <1000 occupying <1% of its historic range.

• 2900 in northern Minnesota•this population has grown so much it was removed from Endangered Species Act protection in March 2009

Recent information (Coastal wolves are 'like no other wolves': study By Judith Lavoie, Canwest News Service March 12, 2009) suggests these are not all one genetic population (i.e. grey wolves).

• The wolves of the west coast (California north to coastal Alaska) have reddish-brown fur, feed on marine resources including seals, salmon and appear to be genetically and evolutionarily distinct from other, contiguous gray wolf populations.

• It is now suggested they may be deserving of separate protection, even while gray wolf populations have grown and been taken off endangered species lists.

Some specific examples of wolf populations and their conservation…

The Wolves of Isle Royale Isle Royale is an American National Park located only about 30 km from the Canadian coastline in Lake Superior. The total area of the main island and a few small surrounding islands which are also part of the park is 540 km2.

• Moose arrived on Isle Royale, crossing a winter ice bridge from Canada, before 1910. With no predators, moose increased to high density, then had large amplitude fluctuations in population size into the 1940s. Peak numbers exceeded 2000 moose in the late 1920s, after the island was made a sanctuary in 1925.

• The cycles were probably due to starvation.

• In 1949, wolves crossed a temporary ice bridge onto Isle Royale, and have lived there ever since.

• Studies of this isolated predator-prey system began in 1953

• Fascinating system since: 1) little or no immigration or emigration; 2) no hunting by humans; 3) little human disruption (e.g. introduced dog diseases); 4) simple ecosystem; 5) confined quarters focuses biological interactions

From early measurements of wolf and moose numbers, moose reproductive rates, and wolf kill rates, L.D. Mech believed that wolves regulated the moose population near an equilibrium value. He thought predator-prey cycles would get ‘tighter and tighter’.

• A study of the ages of moose kills over a number of years on Isle Royale indicated that wolves took principally calves and older animals, i.e. moose with the lowest reproductive values.

• Only during the late 1970s, when moose numbers were low and wolf numbers had increased with pack separation, were any significant number of moose of ages 3-7, the prime reproductive ages, killed. This suggests that wolf kills are not likely to be sufficient to regulate moose numbers.

1959

19850 10 20

Age Class (Moose)

wolf kill highest when moose abundant, lowest when moose numbers were low

• Moose numbers peaked at >1500 in the 1970s, declined during the early 1980s, and increased during the early 1990s, before crashing (80% mortality) due to starvation in 1996 (Peterson 1999).

• Wolf population size has not followed moose numbers.

• Moose density appears to be governed by their relationship with plant food and less by wolf-driven mortality.

• Moose also are affected by parasites (ticks), which build up large populations during warm summers and winters

• Ticks reduce moose vigour, leaving them exposed to more wolf predation. During 2003, the moose population fell dramatically, apparently in response to climate-change induced parasitism by ticks and resulting exposure to wolf predation.

• Most recent numbers (2007): 30 wolves, 490 moose• Winter severity and tick infestation were both regarded as

important in recent year declines in the moose population.

recent population data

see more at: http://www.isleroyalewolf.org/wolfhome/home.html

typically 3 wolf packs, though they vary in number and size of territory through time

Population Control and the wolves of the Yukon• The Yukon government had a 5-year program of controlling wolf

numbers by hunting, trapping and poisoning. The reasons are economic. Hunting of elk and caribou produces a tourism industry of significant value to the territory. As well, there are demands from native communities that the abundance of large game animal prey be maintained or increased to meet the needs of hunters.

• However, other predators contribute significantly to the problem, e.g. both grizzly and black bears.

• The government reduce wolf populations in an area called the Aishihik region around Kluane National Park.

• In this region, both caribou and moose populations have declined and continue to decline even after closing the caribou hunt and greatly reduced moose harvest.

• Even the government admits that the yields of moose and caribou over the last decade were not sustainable.

• Hayes et al. (2003) reported that moose and caribou both responded favourably in terms of survival and recruitment in areas where wolves were controlled and that wolf predation was responsible for low moose numbers

• They further recommended that the government (of which they are employees) limit human hunting to 2 and 5% for caribou and moose, respectively, and that wolf control continue

•Renewable Resource officials admit that there is good evidence from elsewhere that the wolf population will decline as resources become scarce, yet they argue that the long recovery period for caribou necessary (a 'predator pit') with limited wolf control would be unacceptable to their client groups.

• Reintroduction of species into their native habitats is desirable to return ecosystems to a more natural state. The success of reintroduction depends on establishing sufficient genetic variability and in reaching a minimum viable population size.

• Wolves were directly and intentionally extirpated from the park in 1930. They were thought to pose a threat to the herds of deer, elk and other game animals populating the park.

• Is the area into which animals are reintroduced large enough to maintain a minimum viable population?

• For wolves this is a severe problem. The natural density for wolves is about 1 mature animal per 26 km2 (e.g. Frankel and Soule 1981).

• Considering social structure, it was estimated that a minimum area of between 39,000 and 78,000 km2 was needed. However, Yellowstone, the largest park outside the arctic in North America, has a total area of only 9000 km2. 

Reintroduction of wolves to Yellowstone National Park

• One of the ecologically important arguments for its reintroduction is that it is the largest missing mammal from the pre-development Yellowstone ecosystem.

• Wolves were thought to be necessary to restore ecological balance and prevent overgrazers by elk, moose, deer.

• Arguments against reintroduction generally come from ranchers in the area (Montana, Wyoming, and Idaho), who believe that wolves will inevitably prey on livestock.

• The reintroduced wolves were designated a "non-essential experimental population". According to the Endangered Species Act, wolves were full protected within the park and reintroduction area, but ranchers had the right to kill any wolf which endangered livestock. Funds were privately collected to reimburse ranchers for any livestock proven to be killed by reintroduced wolves.

• Reintroduction began in 1995 with 14 animals from British Columbia, followed by 17 more in 1996. Reproduction resulted in a total of 21.

• By the end of 1996 there were 51 wolves.

• In 2003 there were 59 pups and 115 adults or 174 animals.

• Population delisted in 2009, and hunting was allowed in some states (e.g. Idaho, Montana, Wyoming). It is now a “experimental, non-essential population”. The population is protected within

Yellowstone, but not outside, where a limited hunt is permitted.

• The regional population is called the “Northern Rocky Mountains Distinct Population Segment”

• total number (2009) was 1600 in Montana, Idaho and Wyoming, encompassing 95 breeding pairs

The most recent update on Yellowstone wolves shows the population numbers since the beginning of re-introduction:

And the number of pups surviving each year since reintroduction:

• Without the top predator, a trophic cascade occurred. • Populations of elk browse and damage their favorite food,

quaking aspen (Populus tremuloides). • Initial studies of this cascade (Ripple et al. 2001) indicate that

it may well not be wolf predation on elk that affects aspen, rather it is different use of habitats by elk to avoid predation risk that releases some aspen from browsing damage.

• The root suckers (quaking aspen reproduces more asexually than by seed) grow taller in areas used more heavily by the wolf packs in Yellowstone than in areas little used by wolves (and therefore used more heavily by elk).

Why was this reintroduction so important?

• The last of the original wolves introduced to Yellowstone died in early 2003, but the introduction effort has been such extremely successful.

• Yellowstone is not the only site of wolf reintroduction. Wolves have been reintroduced to a number of other sites in the northwestern and southwestern regions of the U.S.

• In almost every area the same objections from ranchers have occurred. The ‘non-essential’ designation and reimbursement for loss has made most reintroductions successful.

Red Wolf• The red wolf (Canis rufus) once roamed the southeastern

US in forests and coastal marshes. It ranged inland to central Texas, Missouri and southern Illinois.

• Ecological extinction of the red wolf over most of its habitat in the U.S. occurred during the 1970s due to human encroachment and development over much of its habitat.

• The last remaining wild red wolves live in coastal marshes in the southeast along the Atlantic coast.

• extinct in wild by 1980• The US Fish and Wildlife Service began a captive breeding

program in 1973 (14 animals used), with 40 different facilities participating today

• As of 1990 there were about 100 red wolves in zoos involved in the program, currently there are about 300

• slowly being reintroduced into wild

• One of the key questions about the red wolf is whether it is even a distinct subspecies of wolf. There was divided opinion, ranging from some who believed it is really a separate and distinct species, to others who believe its gene pool has been so diluted by hybridization with coyotes that it does not deserve any protection or preservation.

• Multivariate morphological genetic analysis doesn't help much in separating out the red wolf. Wayne (1992) used 15 morphometric characters which aligned on two principal components.

The Algonquin Park Eastern Wolf (Canis lyacon)• Wolves of Algonquin Park are smaller (60-68cm at shoulder)

than gray wolves and more uniform in colour.• preys on deer, moose and beaver• hunting ban in place since 2001 in and around the park• Recent molecular genetic data suggests they are closely

related and possibly the same species as the red wolf • Microsatellite DNA and MtDNA analysis suggest that these

wolves are not the result of hybridization between gray wolves and coyotes.

• The MtDNA did include coyote-related DNA, but rapid divergence by mutation indicates that both originated from a line that diverged 150,000-300,000 years ago.

• Neither American red wolves nor Algonquin wolves incorporated gray wolf sequences.

• popular wolf calling events on summer evenings by park personnel

• province compensates farmers for lost livestock

The Florida PantherThe Florida panther, Felis concolor coryi, has some genetic parallels to red wolf. Some of the remaining natural population of panthers carries genes introduced from a (non-sanctioned) released South American puma. The total population is 80 - 100 cats (as of 2006). The Florida panther was distributed from Texas, through the SE USA, though now it is found only in Florida. Males range 400 square miles, females 50.

Genetic analysis indicates that they fall into two distinct stocks. A map indicates the places where panthers have been observed and, based on radio collar locations, the principle areas utilized by the two groups. One uses the Everglades. This group was genetically corrupted by either South American pumas or their captive offspring. Distinct South American genes now persist in the Everglades group.

The second group, living around Lake Okeechobee, is not corrupted, and carries none of the South American genes. Given the scattered observations of individual panthers well outside their principal use areas, that is remarkable. You can see that there is a small presence of mtDNA B in the Big Cypress swamp population.

The red outline indicates Florida panther habitat. Each black dot within indicates a radiocollar localization. The figure comes from Cox et al. 2006. Note the very small number of observations of panthers between the two main population areas.

The remnant panther populations carry a number of signs of what may be inbreeding depression. They almost uniformly have a right angle kink in their tails near the tip and a cowlick in the fur along their backs, almost all males are cryptorchid (only 1 testicle descends), sperm collected from males shows a very high percentage of defective cells (~90%), and heart murmurs are were observed in every kitten born in 1990, as well as 30% of adults examined.

However, even with these problems, births have been more numerous than deaths since 1987. Even that is surprising, since measures of hormonal condition of males and females suggest extensive male feminization due to exposure to xenobiotic chemicals, particularly (likely) PCBs and other estrogenic compounds.

All panthers Everglades panthers

Is there demographic evidence of inbreeding?

A comparison of litter size at birth from 1985 to 1993 to numbers of juveniles of 4-12 months age showed only very low juvenile death rates. At birth, litter size averaged 1.92 kittens (n=25); at 4-12 months an average of 1.89 kittens remained. Depending on which data points you put into a calculation of lx, you can get from .84-.87 as one year survivorship. Considering animals of all ages, annual survivorship was 0.82. All these are high values, not indicative of a survivorship cost to inbreeding.

Is there other evidence that inbreeding is occurring?

There is evidence to suggest inbreeding may be or become important. It’s evidence that females don’t disperse far enough from their natal territories to avoid inbreeding (Maehr, et al. 2002). Females move, on average, only 20.3 km, and this is less than the width of one home range. Males go further (68.4 km). Nevertheless, there is no evidence of successful immigration or emigration from or into existing populations from any others. Both distances are far smaller than those for cougars from further west.

So, what was done to develop an SSP?

As part of the species survival program, eight adult female Texas cougars were recently released in southern Florida to increase the influx of outbred genes into the population. The introduction was suggested by the results of a modeling study using a PVA model called VORTEX, which indicated an 85% probability of species extinction within the next 25 years based on known demographics.

The introduction seems to have been successful. The introduced Texas cougars have died, but 5 successfully reproduced with Florida panthers, producing at least 20 kittens as of 2004.

There was an opposite concern. Some researchers worried over the potential for outbreeding depression. We will find out over the next few years if this happens since outbreeding depression is usually evident in F1 or F2 generations. There is no current evidence from the F1 generation of that depression.

A predictive study by Hedrick (1995) suggested that genetic variability would be markedly increased and inbreeding decreased without loss of adapted Florida panther alleles.

The goal for the introduction of other pumas and captive breeding program was to establish a population of 130 panthers by 2000 in a combination of captive breeding and wild groups, and 500 by 2010.

That is a minimum viable population approach, predicting 95% probability of survival in the wild for 100 years. The wild population continues to remain below 100 animals in 2005-6 (based on the most recent report I could find).

The Florida panther ‘supplementation’ by Texas pumas is a chance to consider how demography and genetics can be used together to assess the likely success of conservation practices. Alexandre et al. (2007) present theory and practice.

In theory, how does inbreeding affect population growth? The replacement rate, R, is reduced (B is lethal equivalents, f is the inbreeding)

R R etB f t

0

The amount of inbreeding is determined by effective population size:

The reduced R affects population growth rate: f N N ft e e t 1 1 2 1 1 2/ /

N R Ne t et t

1

Here’s what the result looks like – growth with and without inbreeding depression…

Solid lines: R0 = 2.25, B = 1, N0 = 2Dashed lines: R0 = 1.25, B = 1 N0 = 10The idea: ???

With small effective population size and slow growth (typical of large carnivores), mildly deleterious mutations are likely to become fixed and accumulate, increasing genetic load (e.g. the various anomalies in Florida panthers). The gradual decrease in fitness leads to what has been termed “mutational meltdown”.

In a species like Florida panther, how many should be released to markedly enhance probability of persistence? The quoted number in Alexandre et al. (2007) is at least 1 – 6 individuals per year, and to avoid loss of local adaptation <10. Note the number of Texas panthers actually released! The individuals released came from a large, but distant population, and were ‘chosen’ from different areas to maximize their genetic diversity.

Genetic and demographic models conditions determined the details of the release.

1.Genetic drift had fixed mildly deleterious alleles in the remaining natural population, resulting in low fecundity.

2.Demographic evaluation led to the release of young adult females.

3.Total release size was 8 individuals. The rate of introduction was 20% ‘injected’ gene flow from outside in the first generation, and 2.5% thereafter.

4.The data you’ve already seen points to success numerically (population increase), in expanded range for the supplemented population, and in genetic ‘health’.

However, there was another problem beyond genetics and demography. The food of Florida panthers apparently includes raccoons. It was discovered that Florida panthers tended to have high levels of Hg in their bodies, as well as other contaminants.

The mercury contamination (probably from its food (raccoons and other mammals, themselves contaminated by agricultural chemicals), affects kidney physiology and brain development.

Panther tissues have also been shown to contain moderate to high levels of p,p'-DDE, methoxychlor, and other organochlorine chemicals. The listed compounds and others are known to act as endocrine disrupters. In other species they can cause feminization of males and impair female reproductive endocrinology and cycles.

So, some of the observed low fecundity may have been due to factors unrelated to the genetics and demography characteristic of small populations.

Interestingly, there was no significant difference in estradiol concentrations among groups comprised of normal males (both testicles descended), cryptorchid males, and females. What this means is not clear.

ReferencesAlgonquin Wolf Advisory Group. 2000. The wolves of Algonquin Provincial Park. Report submitted to John C.

Snobelen, the Minister of Natural Resources, Ontario. 29p.Carroll, C. et al. (2006) Defining recovery goals and strategies for endangered species for endangered species:

the wolf as a case study. Bioscience 56:25-37.Frankel, O.H. and M.E. Soule. 1981. Conservation and Evolution. Cambridge Univ. Press, Cambridge, UK

http://www.fws.gov/bio-gwol.html. Gray wolf (Canis lupus) Meffe and Carroll. 1997. Management for Conservation: Applications. Moore, D.E. 1989. The red wolf: extinction, captive propagation and reintroduction. Bull. N. Y. S. Museum

471:136-139. O'Brien, S.J. and E. Mayr. 1991. Bureaucratic mischief: recognizing endangered species and subspecies.

Science 251:1187-1188. Parker, W.T. and M.K. Phillips. 1991. Application of the experimental population designation to recovery of

endangered red wolves. Wildlife Soc. Bull. 19:73-79. Peterson, R. 1999. Wolf-moose interaction on Isle Royale: the end of natural regulation. Ecological

Applications 9:10-16.  Peterson, R.O. and R.E. Page. 1983. Wolf-moose fluctuations at Isle Royale National Park, Michigan, USA.

Acta Zool. Fennica 174:251-253.Ripple, W.J. 2001. Trophic cascades among wolves, elk and aspen on Yellowstone National Park’s northern

range. Biol. Conserv. 102:227-234. Schmidt, W.E. 1986. Agency seeks to return red wolves to North Carolina. New York Times, Nov.13. Struzik, E. 1993. Managing the competition. Nature Canada 22:22-30. Taylor, R.J. 1984. Predation. Chapman and Hall, N.Y., NY. pp. 30-33. Vila, C. et al. 2003. Rescue of a severely bottlenecked wolf (Canis lupus) population by a single immigrant. Proc.

Roy. Soc. London B.  270:91-97.   Wayne, R.K. 1992. On the use of morphologic and molecular genetic characters to investigate species status.

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genetic consequences of population decline and habitat fragmentation. Conserv. Biol. 6:559-69. Wilson, P.J. et al. 2000. DNA profiles of the eastern Canadian wolf and the red wolf provide evidence for a

common evolutionary history independent of the gray wolf. Can. J. Zool. 78:2156-2166.Wright, R.G. 1996. Wolf and moose populations in Isle Royale National Park.

For the Florida panther:Groom, et al. pp.231, 423, 506

Alexandre, R., D. Couvet and F. Sarrazin. 2007. Integration of demography and genetics in population restorations. Ecoscience, 14:463-471.

Cox, J.J., D.S. Maehr and J.L. Larkin. 2006. Florida panther habitat use: A new approach to an old problem. J. Wildl. Manage. 70:1778-1785.

Facemire, C.F., T.S. Gross and L.J. Guillette, Jr. 1995. Reproductive impairment in the Florida panther: nature or nurture? Environmental Health Perspectives 103:79-86.

Fergus, C. 1991. The Florida panther verges on extinction. Science 251:1178-80.

Maehr, D.S. and G.B. Caddick. 1995. Demographics and genetic introgression in the Florida panther. Conservation Biology 9:1295-98.

Primack, R. 1993. Principles of Conservation Biology.

Radetsky, P. 1992. Cat fight. Discover 13:56-61.