Posts Tagged ‘Soule’

Uncertain Future for the Gray Wolf

 

Again, An Uncertain Future for the Gray Wolf

By Ken Fischman, Ph.D.

August 23, 2012

 

It looks as though Interior Secretary Salazar has struck a deal with Wyoming to end its Endangered Species listing for wolves in that state. According to the New York Times, the arrangement will be similar to that now in force in Idaho and Montana, with a minimum number of 150 wolves and 15 breeding pairs. However, wolves will still be treated as vermin, to be shot on sight year round in 4/5s of the state. Thus, Wyoming has apparently received from the Obama administration most of what it had held out for.

The New York Times August 21, 2012 Editorial, “Uncertain Future for the Gray Wolf, “ (c f.) questioned whether 150 wolves/state would be a viable population for Wyoming, Montana, or Idaho. If you consider that my state, Idaho, contains about 1.3 million people, 20,000 black bears, and over 100,000 elk, the number 150 stands in stark contrast to these populations. No reputable biologist that I know of believes that such a number would be anything but a relict population, genetically threatened by inbreeding, and possibly extinction.

Even Ed Bangs, who was US Fish & Wildlife Wolf Recovery Coordinator, recently admitted that this number of wolves “is not defensible.”
Interestingly enough, the lead article in Science, September 2011, “Trophic Downgrading of Planet Earth”, emphasizes the value of wolves and other top predators in keeping a healthy balance in our ecosystems. It was authored by some of the world’s leading Conservation Biologists. The article is excerpted on the Ancient Pathways web site under the title of  “Trophic Downgrading or Where Have All the Predators Gone,?” and contains a lot of valuable information on the effect of apex predators.

Additionally, Times readers should know that the wolf hunting season in Idaho is now year around, if you count private land, which is about 40% of the state. Any land owner, with a valid wolf tag can shoot wolves on sight. When you consider that the southern third of the state is desert, in which wolves are rarely seen, the territory safe for wolves shrinks considerably more. Also, the number of wolves that can be killed in 8 out of 13 “Wolf Zones” is unlimited.

Obama promised that he would reverse the Bush administration’s politicization of science. This does not appear to be true for wolves. I guess that it is because they do not vote.

———————————————————————————————————————————————

New York Times

EDITORIAL

Uncertain Future for the Gray Wolf

Published: August 21, 2012

A Wolf Pack in Isle Royale NP

Wolves In Isle Royale National Park

Wolves in Montana and Idaho lost their endangered species status last year. Interior had concluded that both states had developed management plans that would keep wolf populations at healthy levels.

The delisting has led to the death of hundreds of wolves in sanctioned hunts. But at least Montana and Idaho established limits on hunting seasons and on the number of wolves that can be taken across the entire state. In Wyoming, by contrast, wolves in four-fifths of the state will be essentially treated as vermin that can be killed at any time, and for almost any reason.

Interior says not to worry. Most of Wyoming’s wolves are in the state’s northwest corner, it points out, and can be shot only during a defined hunting season. Further, the state has agreed not to reduce the statewide population below 150 wolves and 15 breeding pairs.

This is a more protective plan than Wyoming’s politicians, ranchers and hunters wanted a year ago. But whether it’s enough to guarantee a sustainable population is far from clear. Interior has promised to review its deals with Montana and Idaho after five years. It must demand the same of Wyoming. The question there is whether, after five years, there will be any wolves left to review.

 

 

Trophic Downgrading or Where Have All the Predators Gone?

THE TROPHIC DOWNGRADING OF PLANET EARTH

(Or, where have all the predators gone?)

  J.A. Estes, et al. (2011) The Trophic Downgrading of Planet Earth (2011) Science, 15 July, 333(6040) 301-306.

Summary and Comments by Ken Fischman, Ph.D.

This is a paper that is worth your diving into because the information it contains is important to the health of our planet. I will help you get through it by summarizing and commenting on it. You can either read the summary or skip directly to my comments on it at the end of this post. What is it about? It deals with the recent and rapid disappearance of top predators, such as wolves, lions, & sharks, mostly brought about by the actions of that top predator of all – mankind, and the surprisingly profound effects their loss is having on ecosystems worldwide.  It was the feature article in the July, 2011 issue of Science, one of the most prestigious scientific journals in the world. Among its 23 authors are: John Terborgh, Joel Berger, Michael Soule, and William Ripple. The former three are considered to be among the founders of the field of Conservation Biology, and Ripple is our foremost researcher into the effects of top predators on the ecosystems of North America. Simply put, a trophic cascade (TC) is the effect that the absence or abundance of a top or apex predator has on succeeding levels of the rest of the ecosystem. The authors have gathered a vast array of evidence showing that these losses lead to ever-increasing and widespread effects on other living creatures, on ecosystems, and on the Earth itself. Terborgh pioneered this type of study by showing the profound effects of the presence or absence of predators on the fauna and flora of isolated islands in the Barro Colorado, a recently flooded region near the Panama Canal. Soule, in a classic paper, neatly demonstrated how the presence or absence of coyotes effected the bird and cat populations within the urban canyons of San Diego. Ripple has shown the profound influence that the reintroduction of wolves in Yellowstoneand loss of mountain lions in Zion National Park  have had on the animals and plants in those areas. In this paper, these scientists turn their attention to the effects of predators on ecosystems worldwide and warn us of the present and impending dangers that our  steady & seemingly inexorable extermination of predators is having on the Earth

Summary of the Paper

 The loss of apex predators all over the world is having a pervasive influence on nature. There are cascading effects of the disappearance of predators. These “top-down forcings” (causes of variability) are having unanticipated effects, such as increase in disease, wildfires, losses in carbon sequestration, appearance of invasive species, and disruption of biogeochemical cycles. In its 4.5 billion years of existence, our planet has undergone several mass extinctions, with huge loss of biodiversity, followed by novel changes. We are now in the early to middle stages of a sixth mass extinction. Man has mostly caused these recent extinctions. Many of them are started by the removal of apex predators. These extinctions may be mankind’s most pervasive effect on the natural world. Extinction obviously means a permanent loss of these animals, which in turn often has a ripple effect, causing many other changes throughout the ecosystem. These widespread changes are what are referred to by scientists as “trophic cascades” (TCs). Some of the ultimate outcomes of TCs are: fires, disease, climate change, habitat loss, and pollution. Theory behind concept of TCs: (1)  An ecosystem is shaped by its top consumers (usually apex predators). (2)  Alternative stable states. TCs push a system, and it reaches tipping points. These are thresholds or breakpoints, and when they are reached, significant phase shifts occur. (3)  Connectivity – this is built around connection webs and through the mechanics of predation, competition and mutualism (organisms that have a supportive effect on each other), biologically, and through physicochemical processes. Cryptic nature of TCs: Species interactions are usually invisible under stable conditions. They may require years to become evident due to the long generation times of some species.  The effects usually do not become evident until after the loss. The scales of TC s can be much more vast than most feasible scientific studies can handle. Most field biology studies concentrate on small, discrete areas, and on non-motile species, with short generation times, making them easy to  manipulate. This results in an incomplete and distorted picture of apex predator influence. Hence, the authors have written what is called a mega study, which brings together the results of many other similar studies, using similar protocols & subjects. This enables them to combine the studies & to note general principles and draw important conclusions with more certainty. Widespread Occurrence of TCs: TCs have been documented throughout the world. When apex predators are reduced or removed, and sufficient time and space are accounted for, their influence becomes obvious. “Natural experiments” showing these effects are pervasive: e.g. loss of: killer whales, lions, wolves, cougars, sharks, sea otters.

These interactions are often complex. e.g. apex predators have little influence on megaherbivores:  Elephants, hippos, rhinoceroses, etc. in Africa are basically invulnerable to predation. Mostly, therefore effects are seen in the increase in smaller herbivores: e.g. Thompson’s gazelle, impala. Influence of apex predators on autotrophs (An organism capable of synthesizing its own food from inorganic substances, using light or chemical energy. Most plants are autotrophs): (a)  Increase of autotrophs – by suppression of herbivory (any animal that feeds mostly on plants), e. g. the loss of sea otters, which prey on shellfish,  have diminished the health of kelp forests. The extirpation of wolves from forests has resulted in a corresponding increase of ungulates adversely effecting other animals and plants in various ecosystems. e.g. the removal of wolves from what has become Rocky Mountain NP in Colorado has resulted in the overgrowth of elk, which in turn have devastated much of the plant life. (b) Decrease of autotrophs – e. g. large mouth bass by feeding on smaller fish, which feed on 200 kinds of plankton (microscopic aquatic plants & animals)  have decreased their numbers to such an extent in many mid western US lakes, that this has resulted in a loss of oxygen, leading to the demise of other life forms in these lakes. Herbivory and Wildlife: Increase in herbivory (mostly domestic animals that eat plants) has resulted in a change from grass lands to scrub lands, & the burning up to 500 million hectares (ha) in the global landscape and has released over 4,000 metric tons (Tg) of CO2 into the atmosphere. Diseases: e.g. Rinderpest (an infectious viral disease) in East Africa decimated ungulates. (animals like wildebeests & buffalos that chew their cud). This led to an increase in plant biomass, which in turn led to wildfires. Vaccination and control eliminated Rinderpest and this led to the recovery of the wildebeests and buffalos. Because of this, shrub lands became grass lands, which reduced the frequency and intensity of wild fires.

e.g. Impacts of predatory fish on mosquito larvae: effects the incidence of Malaria. Physical & Chemical Influences: There is a linkage between apex predators & atmospheric CO2. e.g.  presence or absence of predatory fish in lakes can effect the production & uptake of CO2. e.g. whaling transferred 105 million tons of carbon from whales to the atmosphere. e.g. Extinction of Pleistocene herbivores reduced atmospheric methane & contributed to a drop of 9° C. temperature drop in the Younger-Dryas period, some 12,900 years ago. Soils: e.g. Herbivores profoundly influence soils. e.g. introduction of rats & arctic foxes in high latitude (mostly arctic) islands reduces soil nitrogen by disturbing nesting birds. Water: e.g. collapse of large demersal (bottom feeders) fish in the Baltic Sea led to a 20% decrease of silica in pelagic diatoms (one-celled organisms that make up the majority of plants found in the open sea). e.g. Yellowstone wolves protect riparian vegetation from over-browsing herbivores. This leads to more shade & cooling of streams, which in turn decreases streambed erosion & increases cover for fish & other aquatic organisms & leads to an increase in songbirds.

Invasive Species: Lack of top-down predators allows invasive species to spread. e.g. spread of the brown tree snake, originally from the Solomon Islands, on Guam, which has exterminated most of its birds, was due to lack of other predators, which could have held the snake population in check. e.g. reduced fish predation in the Mississippi River led to the invasion of zebra mussels. Biodiversity (Abundance of & diversification in living creatures): Biodiversity(BD) is now largely confined to protected areas (e.g. national parks, designated wildernesses). Loss of BD has been mostly caused by over-exploitation (hunting, fishing, increase of areas reserved to domestic & other ungulates, etc.) has led to habitat loss & fragmentation of ecosystems. e.g. over browsing by an increasing population of elk in Rocky Mountain NP is due to lack of natural predators,(i.e. wolves). The same situation occurred in: the Kaibab Plateau, adjacent to the Grand Canyon in Arizona, which was overrun with deer. Minnesota has a serious problem with areas overrun by more than 1 million deer. Princeton NJ had to employ sharpshooters to kill deer, which were overrunning suburban gardens. Deer (ironically) starved on Deer Island in San Francisco Bay due to their burgeoning population, which was unchecked by predators.  Mesopredators (coyotes) in San Diego canyons strikingly changed populations of songbirds and cats.

e.g. Sea Stars in intertidal areas interact with mussels, wiping out many species. e.g. loss of small vertebrates after the extirpation of wolves, cougars & bears in temperate & boreal North American forests changed the ecology of these forests. Effects of Tree Longevity: e.g. wolves & other megapredators were almost entirely eliminated in the US by the 20th century. At that time there began to be recruitment failure & reduced tree growth rate in many places (most obvious in national parks). e.g. wolves were eliminated 100 yrs. ago on Anticosti Island in mouth of the St Lawrence River. This led to a decrease in the number of saplings & an increase in graminoids (grasses), e.g. wolves were extirpated from the Scottish island of Rum 250 -500 years ago, resulting in total loss of its forest. It is now treeless.

Conclusion: “Best management solution is likely restoration of effective predator regimes.” [English translation: Bring back the predators] Paradigm Shift in Ecology: There is clearly a top-down forcing in ecosystem dynamics.  [We argue that ] “burden of proof be shifted to show for any ecosystem, that consumers do (or did) not exert strong cascading effects.” Conclusions: Unanticipated changes in the distribution & abundance of key species, as well as pandemics, population collapses, eruptions of unwanted species, major shifts in ecosystem states, are caused by altered top down forcing , brought about by loss of native apex consumers. Repeated failures to anticipate & moderate such events arise through  fundamental misunderstandings of their causes. Resource managers usually base their actions on the expectation that physical causes are the ultimate drivers of ecological change. “Top-down forcing must be included if there is to be any real hope of understanding & managing the workings of nature.”

 COMMENTS – Ken Fischman, Ph.D.

 I find it helpful in understanding TDG to picture a pyramid, with the predator at the peak or top & prey animals at several successive & increasingly wider levels, (indicating larger populations) underneath. For example, sharks are the top predators in our oceans & they prey on smaller fish such as tuna, which in turn prey on smaller fish like anchovies, etc. until the lowest & most fundamental layer is reached, which consists of microscopic plankton (autotrophs) & is effected in a profound way.

Along this line, I recently read a paper published in Nature by Daniel Boyce of Dalhousie University in which the author utilized hundreds of thousands of historical records to show that the clarity of most of our oceans has been greatly increasing in the past few years. This is an indirect but powerful method, showing that plankton populations are decreasing rapidly. Because plankton are the base prey in our oceans, their scarcity would adversely effect all fish populations & since they are the ultimate autotrophs (think of what would happen if their dry land equivalent, grasses, were to decrease considerably) tend to increase CO2. Such a profound worldwide change undoubtedly has more than one cause, but the disruption of world fisheries through the loss of top predators is probably a contributing factor.

It is easy to overlook the effects of some predators, either because they are not charismatic megafauna, like “lions & tigers & bears oh my!” or are out of sight much of the time. For instance, who would even thought of sea stars as predators? I know that I had not until recently despite my background in Zoology.  Yet it has been shown that their loss can have profound effects on shellfish.  And those cute little sea otters. Who would have thought that they have an important effect on kelp beds? The film, “Jaws,” which came out in 1975, gave sharks a bad name that they have yet to overcome. That, together with the insatiable appetite of Chinese & other Orientals for shark fin soup (Talk about waste. They cut off the fins & throw the shark carcass away) & the dislike of commercial fishermen for sharks, who they view as competitors, in the same way that many elk hunters view wolves, has led to their wholesale destruction. No thought was given to the sharks’ role as the ultimate apex predator in the sea & the  effect their demise is having on other fish lower in the TC pyramid. It is quite possible, even probable, that the loss of many commercial fish species is linked not only to overfishing but also to the destruction of sharks, which has upset the ecological balance in oceans. In this connection, commercial fishermen may be doubly responsible for the serious depletion of fisheries worldwide, through their overfishing & destruction of apex predators.

My own studies on wolves and as an advocate for them has given me a fresh perspective on their importance in maintaining healthy forests. In this respect, the authors’ citing of studies showing that the eradication of wolves changed the flora of Anticosti Island in the St. Lawrence estuary & deforested the Scottish island of Rum, is instructive & worrying.

We do not however, need to go to the ends of the earth to find examples of TDG. In my own little part of northern Idaho, we have seen the results of overfishing in Lake Penderay, invasive species like spotted knapweed & the infamous zebra mussels, and loss of biodiversity caused by overpopulation of elk in the Clearwater NF. There are a substantial number of elk hunters in the state of Idaho, whose idea of heaven seems to be forests containing only elk & hunters. One of their leaders recently stated that he would only be satisfied when hunters success rates reached 90% Success rates throughout the Northwest have been historically at around 18 -20% (Spokesman Review 2/22/08). Idaho already contains over 100,000 elk. He apparently wants to turn Idaho into an elk farm, where hunters do not even have to get off their ATVs to kill elk. I doubt that many other Idahoans would agree with that vision. These hunters & the politicians who support them are responsible for the present vendetta against wolves, which in the last year has resulted in the killing of around 429 out of only 760 wolves in this state & the extension of the wolf hunt to year around, a hitherto unheard of strategy for “managing” wildlife.

I hope that this publication on the importance of top predators, like wolves, will be brought to the attention of state wildlife organizations like IDF&G and will result in a change of their policy toward a greater respect for these animals. For those of you who are interested in finding out more about this fascinating & important subject of how the loss of top predators is effecting the earth, I recommend the following books:

Monster of God – by David Quammen A very readable account of how our fear & killing of predators is changing the world.

Where The Wild Things Were – by William Stolzenberg A journalist writes about the research that been revealing the key role that predators play in ecosystems.

Song of the Dodo – by David Quammen One of our best scientific & nature writers chronicles the researchers & their studies who have created the new field of Conservation Biology.

Of Wolves and Men – by Barry Lopez A brilliant examination of wolf biology & the often-searing history of mankind’s relationship to these fascinating & badly misunderstood animals.

Wolf Country – by John B. Theberge. The results and conclusions of wolf biologist from an eleven year study of wolves in Algonquin Park, Canada. This book includes a lot of valuable information, written in a readable and popular format.

MYTHS & FACTS ABOUT WOLVES

                                                                       MYTHS & FACTS ABOUT WOLVES  (1/16/12, Rev. 6/15/13)

Northern Idaho Wolf Alliance (NIWA)

and

Ancient Pathways to A Sustainable Future

Contact: Ken Fischman, Spokesman

bigfish@gotsky.com

•      Minnesota’s wolf population has been stable, at 3,000 since,(2004, 5X as many as in Idaho).

•     Wolves were removed from the Endangered Species List by

a political manoeuver, in placing a rider on a must-pass appropriations

bill. It was never voted on or even debated. This marks the first time an

animal was removed for other than scientific reasons.

•     Wolves were hunted in Idaho barely five months after being taken off the

Endangered Species List. No other species has had this happen to

them. Almost 300 wolves were killed in Idaho & Montana’s first hunts

in 2010 and this number increased to over 550 in 2012.(did not include wolves killed for livestock depredation)

•   In most of Idaho they did not even setting an overall quota for the

2011 – 2012 hunt. Hunters may kill as many wolves as they can,

individual hunter limits are 10 wolves each, & they are

allowed to utilize: traps, baiting, & electronic wolf calls to do so.

•    The killing of such a large percentage of the wolf population

amounts to a slow motion extermination campaign. It is certainly not

“Managing” wildlife.

•     The 2011-12 Idaho wolf hunting season was 10 months long – beginning

September 1st. & ending in June. This long a hunting season is

highly unusual for any animal, & impacts the wolves’ mating denning

seasons.

•   The  long wolf hunting season creates an almost year-round danger

for hikers, bird watchers, campers, & boaters from accidental shooting

by hunters. It is not safe to go out into the woods at any time now.

•    There have been only two authenticated killings of humans by wolves

in North America in the last 200 years, You are in greater danger of

killed by a dog. Dogs killed 27 people in 1997-1998 . 

•   Wolves belong in our wild areas. They are an essential part of a

healthy and functioning ecosystem. As an apex or keystone

predator they are crucial to the well being of everything from

flowering plants and trees to insects and all the other mammals,

including elk and deer.

•     There has been talk about the Idaho wolves being “aliens” because

they were introduced from British Columbia & Alberta. These statements

have no scientific basis. All state wildlife agencies as well as independent scientists

agree that  genetically, the wolves that

were historically eradicated from the northern Rockies

and the wolves that have been re-introduced in the past

decade are the same species, Canis lupus.

•     There have been wild claims that these wolves are huge, many over

200 pounds. All 188 wolves killed in the first Idaho wolf hunt in 2009 were officially

weighed by IDF&G agents. The average female was 86 lbs. and the

average male, 101 lbs. The largest was 127 lbs.

•     Many hunters claim that wolves are decimating elk herds – According to the Rocky

Mountain Elk Foundation 2007 Report, the Idaho elk population has been above

100,000 since 1985, and the Northern Rockies elk population has

increased 32.9% in the last 25 years, to over one million animals. Elk #s

increased by 3,000 in 2010 alone.

•     Idaho’s elk population fluctuates, but the hunters’ have a

perception that elk numbers are decreasing. This is probably due to the

wolves pushing elk off the valley floors and into the mountains,

making the hunters work harder to find them.

•     Contrary to the claims of ranchers, wolves are not killing off large

numbers of  livestock – According to the USDA

Statistical Bureau they are responsible for less than 2% of all

livestock deaths due to predation( less than 0.1% in Idaho).

In 2008, feral dogs killed more than four times as many sheep in Idaho than wolves did.

Eagles and other raptors carry off far more lambs than wolves kill.

•    There are 2.2 million cattle in Idaho. Last year wolves killed 71 of them.

Can you do the math to figure out the % killed? Hint: It is less than 1/100th

of 1%.

•     IDFG’s “wolf-management” strategy will reduce wolves to a remnant

population. Most wolf biologists agree that they  would become genetically isolated,

prone to inbreeding and inherited diseases, and unable to perform their historic

function in bringing balance to the ecosystem.

•     IDFG is using conflicting numbers when reporting wolf population.

They assumed a steady annual increase of 20 to 22% whereas in

reality Idaho’s wolf population increased by 8.8%, 15.6%, and

dropped 0.4% in 2007 , 2008, and 2009 respectively. In 2012, they decreased 11%. (USFW statistics).

•     In Yellowstone National Park the wolf population fluctuates. They declined by 27%

in 2007, & they lost nearly all their pups due to severe weather, disease, and prey scarcity. This happened again in

2008.- and this is in a place where they aren’t even hunted.

• There has never been a single case

of livestock depredation due to wolves reported in Idaho’s Panhandle.

and IDFG estimated the wolf population there to be a

minimum of 55 wolves in 2012.

Nevertheless, the wolf hunt quota for the Panhandle was removed.Hunters killed 71wolves there.

•     IDF&G’s attitude toward wolves is that they are damned if they do

& damned if they don’t. If wolves kill livestock, IDF&G retaliates. If

they do not kill livestock, they want them killed anyway they say, in order to reduce the possibility of livestock depredation.

•     Anti-wolf people claim that wolves are infected with tape worms(Echinococcus),

& that they are a threat to infect hunters with the worms. The Montana &

Idaho wildlife agencies as well as independent scientists have stated that

these worms were endemic to domestic livestock long before

the wolves were restored. Big-animal veterinarians

testified in state legislatures that there is little or no danger of people becoming infected.

All wolves released in Yellowstone and Idaho in 1996 were dewormed first.

•     If you chunked up Idaho into areas each of 100 square miles and

evenly distributed people, elk and wolves among the chunks you

would have in each chunk 1,800 people, 140 elk, and 1 wolf. That

demonstrates how few wolves there really are. How are they to

fulfill their role of keystone predator?

The Case of the Missing Predator, or Please Pass the Shark Fin Soup

The Case of the Missing Predator, or Please Pass the Shark Fin Soup

THE PREDATOR/PREY RELATIONSHIP. WHY IS IT SO IMPORTANT?        

From time to time in this website, we examine important scientific papers in light of what they show us about subjects of interest to ourselves and our readers.

         The following paper (Crooks and Soule, Nature, 1999) has become a classic because it vividly shows how the presence or absence of a predator can have unexpected and important effects on an ecosystem.

(I regret that I cannot reprint the entire paper, and can show you only the abstract. Copywrite policies prevent me from doing so, even if I were to purchase it. This is detrimental to the free flow of scientific information, but I have no control over the situation.)


Mesopredator release and avifaunal extinctions in a fragmented system

Kevin R. Crooks1 & Michael E. Soulé2

  1. Department of Biology, University of California, Santa Cruz, California 95064, USA
  2. The Wildlands Project, PO Box 1302 2010, Hotchkiss, Colorado 81419, USA

Correspondence to: Kevin R. Crooks1 Correspondence and requests for materials should be addressed to K.R.C. 
(e-mail: Email: krcrooks@earthlink.net.).

Mammalian carnivores are particularly vulnerable to extinction in fragmented landscapes1, and their disappearance may lead to increased numbers of smaller carnivores that are principle predators of birds and other small vertebrates. Such 'mesopredator release'2 has been implicated in the decline and extinction of prey species2, 3, 4, 5, 6. Because experimental manipulation of carnivores is logistically, financially and ethically problematic6,7, however, few studies have evaluated how trophic cascades generated by the decline of dominant predators combine with other fragmentation effects to influence species diversity in terrestrial systems. Although the mesopredator release hypothesis has received only limited critical evaluation8 and remains controversial9, it has become the basis for conservation programmes justifying the protection of carnivores6. Here we describe a study that exploits spatial and temporal variation in the distribution and abundance of an apex predator, the coyote, in a landscape fragmented by development. It appears that the decline and disappearance of the coyote, in conjunction with the effects of habitat fragmentation, affect the distribution and abundance of smaller carnivores and the persistence of their avian prey.

Letters to Nature

Nature 400, 563-566 (5 August 1999) | doi:10.1038/23028; Received 22 February 1999; Accepted 5 July 1999


The Soule paper was a sort of scientific detective story.

Michael Soule, who is considered to be the dean of the field of Conservation Biology, if not its creator, examined a puzzling situation in his home city of San Diego, California. The city, although it is highly urban, is transected by many deep and mostly wild ravines that extend out to the ocean front. The ravines contain animal populations and are basically isolated from each other by houses, streets, etc. One can think of them therefore as islands of life, the denizens of which can enter and leave only with great difficulty.

When Soule surveyed the animal populations in these ravines, he noted a strange situation. In some of the ravines there were dense populations of song birds, whereas in others, there were hardly any at all.

The mystery was clarified when Soule examined the other animal populations in these “urban islands.” He found cats in some ravines, and coyotes in others, but never cats and coyotes together. He also noted that in those ravines where there were coyotes but no cats, there were plentiful populations of song birds, but in others where there were no coyotes, but many cats, song birds were missing.

This is partially a big fish, little fish story, with intriguing consequences and implications. The picture that Soule put together was the following: Coyotes and cats are both predators. We call coyotes mesopredators because they themselves are the prey of others, such as mountain lions and wolves. Coyotes, in turn prey on cats and cats eat birds as well as their eggs and young.  Did you ever think of your kitty as a predator when it brought a dead creature home? Well, domestic as well as feral cats are responsible for the deaths of millions of song birds every year!

In those ravines where the only predators were cats, the cats decimated the bird populations. However in those ravines where there were urban coyotes, they preyed on the cats, keeping their numbers way down, thus allowing the bird populations to flourish. Mystery solved.

So, what has this to do with our interests? Just this.  Wolves are keystone predators, meaning that they sit on top of the food chain (if humans are ignored), and due to this situation, their behavior and eating habits result in a cascade of effects to the rest of the ecosystem.

Yellowstone National Park, like those San Diego canyons, is a sort of island of wildlife, surrounded by ranches, highways, houses and other accoutrements of human habitation. Animals do not easily get in or out. When a few wolves were reintroduced there in 1995, some of the effects were anticipated, but others were not.

 The effects of these predators have been widespread and profound. First, they reduced the number of coyotes in the park considerably as the wolves took their place as the top predators in Yellowstone. Then they reduced the elk population from roughly 15-17 thousand to around 4,500 – 5,000 at present. Lest you think that this drop in elk population is the nightmare hunters fear it is in other locales, it all depends on whose ox is gored.

In fact, the elks, themselves an introduced species in the 1930s, had increased greatly in numbers, due mainly to the lack of predators. They overran and overgrazed the park, considerably  changing the ecosystem. How profound these effects were became apparent when the wolves reduced elk numbers and changed their behavior, by chasing them from the river bottoms into the hills.

Aspens, willows and other water–loving plants began to grow in riperian areas, resulting in the stabilization of crumbling creek banks and increasing the amount of shade. Cold water fish, like trout, returned to shaded, cooler waters. Other animal species also benefitted. Animals that depended on the availability of carrion left by the wolves, such as vultures, crows, and foxes made a strong comeback.

These changes have been examined in many studies of the Yellowstone ecosystem by Ripple as well as Creel, W.D. Smith, and Hebblewhite. The documentary film, Lords of Nature, dramatically shows the effects of these changes, both in Yellowstone and in Zion National Park, where extirpation of mountain lions in the main valley has resulted in its being highly degraded by the ever-increasing deer population. In side canyons, where mountain lions still live, the riperian plant and animal life remains lush.

In Yellowstone, the elk and wolves have alternated in population bursts. When wolf numbers increased, the elk numbers diminished. Then the wolf population, stressed by lack of prey, dropped in turn, enabling the elk to make a comeback. These cycles have been observed a number of times during the wolve's 16 year sojurne in Yellowstone, as the wolves and elk repeated their predator/prey dance.

In recent years, the roles of predators in keeping an equilibrium in other species have been intensively studied in many ecosystems. Their value more appreciated by biologists than by the general public. Who knew for example what profound effects the loss of sharks, who are top marine predators, would have on the world’s fisheries. Shark fin soup anybody?

Biogeographic And Genetic Factors In Northern Rockies Wolf Populations

 

       Biogeographic and Genetic Factors in Northern Rockies Wolf Populations

Ken Fischman, Ph.D.(Genetics)   April 9, 2008

 

         As we all know, Fish & Wildlife (USFW) has proposed delisting the wolf populations of Idaho, Montana, and Wyoming. They have recently estimated total wolf populations in these three states to be 1,242, with 92 breeding pairs.  Wolf population in Idaho is currently estimated at 672 ( Nadeau et al., 2007), with 42 breeding pairs (Bangs, Personal Communication, 3/8/07).

         Idaho Fish & Game proposes maintaining a minimum of 100 wolves in their state, with a minimum of 15 breeding pairs (IDFG, 10/07). 

         This paper examines these two population targets, some recent thinking about the genetics and biology of wild animal species, and finally the possible biogeographic and genetic consequences of the minimum number of wolves projected by the Idaho authorities.

          First, let’s look at the effects of population size on the viability of a species. The Hardy-Weinberg Principle states that allele frequencies (that is different forms of a gene) will not vary over time in a population. However, this principle only holds for a population sufficiently large to overcome the tendency for Genetic Drift to change gene frequencies. 

         Genetic Drift refers to the tendency for genes to become more common or more rare in successive generations.  It has no preferred direction, and it tends to sweep genetic variants out of the population with time.  It thus opposes Mutation, which introduces novel variants into the population, thus increasing species resiliency.  i.e. the ability to resist demographic shocks and adapt to changed conditions.

         Small populations often show a Founder Effect, in which one or more gene variants increasingly predominate as inbreeding increases. Inbreeding Depression, results from an increase in homozygosity. That is the state in which there are two identical copies of genes.  Homozygosity increases the possibility of recessive alleles expressing themselves. Some of these will turn out to be valuable, but most will be deleterious, thus weakening the genetic fitness of the population.

         Wolf packs, due to their size, and if they are effectively isolated from other wolf populations, also may show a Founder Effect, thus adversely effecting the long-term survival of the population. The increase in homozygosity would in turn be responsible for high frequencies inherited diseases.  This is something that wolf biologists should be on the watch for.

          What counts in small populations is not their census size, but the Effective Population size or number of breeding individuals in the population. The literature on wolves indicates that most packs have only two Effective Breeders.  However, the latest data on Yellowstone packs show multiple breeders within some packs (Smith, 2006).  I am curious as to whether this is also true for other northern Rockies wolf populations.  On the other hand, can this situation be attributed to something unique about Yellowstone wolves, such as access to large prey populations or lack of stress?  An answer to this question would be important for calculating viable population numbers.

         Let’s examine some of the other possible consequences of small population size.  Small populations in particular are prone to large fluctuations in size. Therefore, it is important to consider this in some detail.  Why does this occur?

           Inbreeding is one source of changes in population size.  The smaller the population, the more likely it is that related individuals will breed with each other, and their offspring will have a far higher number of homozygous genes.

         That is hard to detect, but its consequences, although sometimes subtle, can be severe.  Michael Soule showed that inbreeding of Poland Swine lead to deleterious effects in as soon as the second generation.  The inbreeding resulted in decrease in piglets/litter, decreased survival of newborns, and skewed sex ratios.  As we shall see, this last may be of particular importance for wolves.

         As I previously stated, inbreeding leads to lack of genetic diversity, which in turn may result in inability to adapt and evolve under changing conditions.

         There are also Demographic effects.  One such effect would be fluctuations in the size of small populations. Another is possibility of imbalance of sexes, and increasing chances of a same sex generation. For example, 3 offspring’s chance of being the same sex is 0.25 or 1/4.  If a population remains at a low level for several generations, then a same sex generation becomes almost inevitable.

         Here is an example of a problem resulting from such a situation. One of the last populations of Kakapo, an extremely rare, flightless parrot, was found on an island off the coast of New Zealand.  There were 18 of them. Unfortunately, they were all male.

         A small population is also susceptible to  Environmental effects, such as forest fires, disease, climate change, etc

         Anthropogenic effects loom large for small populations.  These are events such as: accidents, hunting, killing of so-called problem Wolves, and illegal takings. This last is of particular importance in Idaho.  Since wolf reintroduction, 59 cases of illegal hunting/killing have been documented by ID F&G.  Due to its furtive nature, this is probably only a portion of such deaths. 

         Also, last year, 45 Wolves were deliberately killed by ID F&G, USFW, and ranchers. These deaths add up to more than 6% of the Idaho Wolf population.

         All of these effects contribute to population decrease, both directly and indirectly by damaging the social structure of a pack.  Most anthropogenic effects are indiscriminate acts with unforeseen consequences.  For instance one of the pack members killed might be the Alpha female.

         There are of course important Genetic consequences, resulting from the decreases in population size brought about by these demographic, environmental, and anthropogenic effects. As previously stated, inbreeding and small population size will increase the degree of Homozygosity. Recessive genes only express themselves when there is a double dose of them. And, because most harmful genes are recessive, this will result in a larger number of unfit animals and a greater number of deaths.

         Homozygosity also results in an increase of Monomorphisms and an associated  decrease of Polymorphisms, which are multiple functional alleles in a population. This can be damaging, especially if genes effecting the Immune system are involved.  The situation can also lead to a continuous and therefore increasing fixation of deleterious genes. We give this the fanciful name of “Muller’s Ratchet,” which is the continual loss of individuals with the smallest number of deleterious genes because there are so few such individuals.  Due to the elimination of these individuals, generation by generation, the population’s genetic load of damaging genes increases, thus decreasing its adaptive fitness, and leading to its eventual extinction.

         As the expression of recessive alleles become more common due to increase in homozygosity, a species becomes less fit because they are less diverse and therefore more subject to mass die-offs due to disease, etc.  Heterozygosity, in contrast, is increased by outbreeding, leading to improved adaptive fitness of the animals.                

          I would like to put the 673 wolves in Idaho in demographic and geographical perspective.  The size of Idaho is 82,751 square miles. That works out as one wolf for every 123 square miles.  The Human population is more than 1,240,000, which means one wolf for every 1,842 people.

         The chief prey of Idaho wolves are Elk. Their 2006 numbers were estimated  by IDFG as 102,706. The Wolf population of Idaho is actually very small in comparison.  There are 153 Elk for every wolf. 

         Geneticists and Biogeographers find it useful to employ the term Minimum Viable Population or MVP.  This is defined as the smallest population size likely to persist indefinitely in a particular area.

         Here is a little history lesson.  Main and Yadov(1971) examined marsupial populations on several Australian offshore islands and came to the conclusion that a minimum of 200 – 300 animals was necessary to maintain those populations.  However, they also concluded that MVP differs from one species to another, and according to conditions.

          Conservation Geneticists usually consider that a population of less than 500 individuals is endangered, Keep in mind however, that what is important to species preservation is not total population, but the number of Effective Breeders, and many Conservation geneticists recommend a minimum of 50  breeder pairs.

          If we assume an average of ten wolves/pack, with one breeding pair, this would extrapolate to a population of 500 wolves.

         It is of course self-evident that larger populations are usually safer for the viability of a species or sub-population of a species. The key question remains as to what is the minimum number of individuals that would put a population at risk of extinction. 

         All of the factors I have previously mentioned are involved in such a determination, but perhaps another factor is more important in this situation. That is whether or not there is such a thing as a megapopulation of wolves in the northern Rockies.

         USFW speaks of a northern Rocky wolf megapopulation, connected by wolves dispersing from packs.  The megapopulation they describe extends from Canada, western Wyoming and Montana to central Idaho, and from there to northern Utah, a distance of approximately 800 miles.

         Such a connection is particularly problematical between central Idaho and Northern Utah, yet the US FW has conflated what appear to be two distinct areas. I do not know of any data that supports this idea. Lets examine the evidence for the existence of such corridors:

         Since wolf reintroduction, and through the winter of 2006, eight wolves traversed between northwest Montana and central Idaho. Of those, only three have successfully bred. Attempts made by wolves to move between the central Idaho and Yellowstone populations have fared even worse. Only one wolf completed the journey in eleven years since reintroduction (Robinson, 2006)

         These numbers of dispersing wolves are so small that they are likely to have little or no effect on gene flow between these populations.  Additionally, the fact that in such a long time, span, only three of the nine dispersing wolves bred, makes it likely that a larger number of wolves would be necessary if their movement between these regions could be successfully translated into significant gene pool effects.

         To settle the question as to whether these so-called corridors have a real effect, it would be best to do comparative genetics studies between populations rather than to continue to track lone wolves.        

         Much has been made of the rapid increase in wolf numbers since the initiation of wolf recovery in the 1990s. This increase has been cited by the USFW as a sufficient reason to remove them from the Endangered Species list.

         Is this population increase truly remarkable, or is it due to the rapid filling of an ecological niche for a keystone predator that had been nearly empty for well over a century?  Only time will tell, but I suspect that as these niches fill, rates of increase in wolf population will slow down. This is especially liable to occur because many of the conditions that led to wolf extinction in the lower 48 in the first place, are recurring. Hunting, culling of so-called problem wolves, and illegal takings may result in destruction of the intricate social fabric of wolf packs, putting them at an even greater risk of a second extinction.  Just the other day, someone in eastern Idaho shot two wolves because they “were near his ranch.”  (KPBX radio, 4/3/08).

         It is a frequent mistake to assume that current trends will persist indefinitely into the future.  To assume that wolf populations will continue to increase at present rates is as biologically naive as were the assumptions of homeowners and Wall Street investors who have lately discovered that ever-increasing housing values are an illusion.  No one escapes the laws of Nature indefinitely.

                  So we turn to the key question of what is the Minimum Viable Population for Canis lupis?  It is important to realize that MVP has two corollaries, having to do with population size and time: (1) The smaller the population, the more likely it will go extinct within a certain time period.  (2) The longer the time period, the more likely extinction is for a population of any size.

         Mark Shaffer, in his studies of Grizzly populations in national parks, suggested that a 95% chance of persistence for 100 years would be a reasonable goal.

         Conservation Geneticists have recently set more stringent parameters of a 99% chance of persistence for 1,000 years.

         In reality, viability is too complex an issue to be reduced to a single number.  A population of some specified size might be viable under one set of circumstances, but not under another set, or viable for one species, but not for another.

         Soule and Gilpin (1987) came to the conclusion that theoretical numbers cannot be relied on, only real data, analyzed in complex ways and checked against real-life situations can be relied upon.  They called this method Population Viability Analysis (PVA).

         So, how large a population is sufficient to insure viability?  Soule stated that arguing from theory, several lines of analysis produce estimates of several thousand or larger. He said “ I am assuming a 95% expectation of persistence, without loss of fitness, for several centuries.  My guess is that it would be in the low thousands.  …estimates below this range should be an automatic signal for scrutiny.” (Soule. 1987)

         However he leaves us with the following warning:  “…anyone who applies the few thousand estimate to a given species, citing this author as an authority, deserves all the contempt that will be heaped on him or her.”

Considering all the evidence accumulated, it is clear that the wolf management plans of the federal and state agencies are not based on sound scientific and genetic data or theory.  If they are carried out as presently planned, they will undoubtedly lead to genetic impoverishment and possibly to a second extinction of wolves in the Rocky Mountain region.

Delisting isn’t based on sound science

 

April 15, 2009

Idaho Statesman

Delisting isn’t based on sound science

BY KEN FISCHMAN, Ph.D. AND NANCY GILLIAM, Ph.D. 

Secretary of the Interior Ken Salazar recently ruled that wolves be removed from the Endangered Species Act protected list.

We do not understand how he could have given this complex issue the thorough review it deserved in six weeks. Sadly, we suspect that this is yet another in a long history of political decisions about wolves, and not the scientific one that we had hoped for from this new administration.

The U.S. Fish and Wildlife Service claims that the wolves have made a significant comeback, and that a population of 1,500 wolves in Idaho, Wyoming and Montana will ensure their continued viability. Their number is not a biological reality, but a bureaucratic concept. In reality, there are three distinct populations, each numbering in the hundreds.

Ed Bangs, the wildlife service wolf coordinator, claimed that he had new evidence of genetic connection between distant wolf populations because, in 11 years, a few wolves have wandered between Yellowstone and Central Idaho. What counts biologically is not that a few lone wolves have made long journeys, but whether they have contributed genes to the other populations.

Bridgett vonHoldt from UCLA and her colleagues, in their recent study of the genetics of 500 wolves, has demonstrated that there is no gene flow between these three geographically distinct populations.

Scientists tell us that by 2050, from one third to one half of all species will go extinct due to climate change and habitat loss. Those already on the brink are likely to disappear first.

The low number of wolves living in the Rockies now leaves them vulnerable to inbreeding and environmental challenges.

With populations segregated, predicted habitat changes from warming temperatures are a further threat. We already are seeing habitat loss because of increased acreage burned in forest fires, increased tree mortality caused by disease and increased severe weather patterns.

The principles of conservation biology, the science that deals with extinction and viability of wild animals, also indicate that present numbers of wolves in the Rockies are too low. Michael Soule, the dean of conservation biology, has estimated that biologically viable populations would be “several thousand or larger.”

Our point is not that the wolves should never be delisted, but that doing so at this time would be premature. In a manner of speaking, the wolves are not yet out of the woods.

We do not have to guess at the consequences of premature delisting. In January, when the Bush administration attempted to delist wolves, they were left unprotected for three months until a federal judge issued an injunction. During that time, 132 wolves were killed. At that rate, the entire Northern Rockies wolf population could go extinct in three years.

The big, unanswered questions are what is the minimum biologically viable population for wolves, and how many wolves are necessary to ensure gene flow between the various populations and to avoid the consequences of inbreeding, such as loss of vigor, birth defects and decreased survivability of pups.

President Obama has been promising us a science-based approach to such issues. In fact, the president stated recently during his stem-cell research signing, “É We make scientific decisions based on facts, not ideology.” This is what we would like to happen with respect to wolves.

We were signatories of a letter to Salazar from Northern Rockies groups urging him to convene an expert panel of non-governmental scientists, who would examine the wolf issues.

Wolves have been a matter of bitter contention in the West. Science-based conclusions of a panel of experts may offer a way out of this dilemma, if both sides could be persuaded to accept its conclusions. If the Salazar decision is left to stand, it is certain that these issues will be dragged into court again.

Ken Fischman is spokesman for the Northern Rockies Wolf Group and Nancy Gilliam is director, Model Forest Policy Program. Both are from Sandpoint.