Posts Tagged ‘conservation biology’

The Incredible Shrinking Megafauna

An Elk With Majestic Racks

Elk With Majestic Racks

The Incredible Shrinking Megafauna 

 By Ken Fischman, Ph.D.

Part 1 – Of Wolves and Elk

Doug Smith, who is in charge of the Wolf Recovery Team in Yellowstone National Park (YS) said, during a December 17, 2009 interview by The Billings Gazette, that he had recently been seeing something that he never before witnessed. Several times he had watched a bull elk successfully fight off a pack of wolves. Smith said that the bulls had become so large and had such massive racks, that they were now a match for the wolves. What has happened to the Yellowstone elk to bring this about, and why?

As background to this question, you should know that a fascinating, natural experiment has been taking place in YS ever since wolves were reintroduced there in 1996. By “natural experiment,” I mean one that was unplanned and unforeseen. The last naturally occurring wolf in Yellowstone was killed in 1927. Lacking natural enemies with the wolves gone, and with hunting also prohibited in national parks, the elk proliferated over the years. By 1996 the YS elk population had burgeoned to from 15,000 – 18,000. They overran the area, overbrowsing and damaging the ecosystem in many ways. Then came the wolves, 45 of them. In the 17 years since then, the wolf and elk numbers have changed drastically. The wolves increased, up to around 160 individuals, and thereafter they have fluctuated periodically between that and to less than 70 animals, while the elk have decreased to between 5 – 7,000 animals. You can say that the elk and wolves are participating in a mutual dance of death. The wolves reduce the number of elk by preying on them until the elk become scarce enough so that the wolves find it hard to continue to maintain their own numbers. That situation, together with other stresses, such as hard winters and disease, reduce the number of wolves. Up come the numbers of elk until the wolves, with prey easier to obtain, become healthier, less stressed, and begin to increase their population again. This dynamic fluctuation of the wolf and elk populations has occurred several times during the relatively short span that these animals have been interacting in Yellowstone.

Erosion On A Yellowstone Creek

Creek Bed Erosion

Other dramatic changes have taken place in the Park during this period. William Ripple and his colleagues have documented several changes in YS riparian habitat.  It is rapidly being restored, with cottonwoods, willows, and aspen again growing along the hitherto eroded stream banks, which have regained stability. This has resulted in clearing the water of turbidity and debris. Expanded tree coverage along creeks and rivers has also lowered water temperatures, bringing back cold water fish, such as trout, along with song birds, and many amphibians.. The presence of more carrion, a byproduct of wolf predation, has proven beneficial to a whole string of scavengers, like vultures, crows, ravens, foxes, and coyotes.

Young Willows, Growing on the Bank of a Yellowstone NP Creek

The presence of wolves in Yellowstone National Park has changed the habits of elk there. They no longer overbrowse riperian vegetation, but have moved away from stream beds where they used to provide tempting targets for wolf predation. This has resulted in new growth of willows (shown here), cottonwoods, and other stream side vegetation.

Ripple attributes these changes to the presence of wolves, and indeed he has documented similar changes in Banff National Park in British Columbia, as well as in other locales. But aside from all these changes, the one that strikes me from an evolutionary point of view, is the vision of these elk bulls, with their majestic racks. Why has this happened? From the point of view of genetics, the answer seems simple enough. Wolves prey mostly on the weak, disabled, and sick, as well as on bulls, calves, and does, simply because the former are the easiest to kill. Thus, the wolves are removing genes from the elk population for smaller, less robust bulls. If you think about it, hunters do the opposite. They go after the big bulls with the most imposing racks. Their success therefore removes the very genes they most prize, and results in smaller, weaker elk. Now, you may find it hard to believe that humans can have such drastic effects on the genetics of wild animals. However, I have come across some rather startling evidence that I believe will convince you.

First of all, we can turn to the father of the theory of evolution himself, Charles Darwin. Much of the evidence that Darwin accumulated in the eighteen hundreds for his then revolutionary theory, was obtained through observation of and breeding experiments on domestic animals.

The Father of the Theory of Evolution, Charles Darwin

A portrait of Charles Darwin, who is credited with the theory of evolution.He was particularly interested in pigeons, and actually became a pigeon fancier and breeder himself. Along the way he grew convinced that all pigeons in their incredible variety, were descended from wild doves, an idea that contemporary geneticists, using DNA studies, have shown to be accurate. Pigeons, and other domestic animals, have been derived from populations of wild animals, and deliberately bred for characteristics that humans wanted, resulting in present day cattle, sheep, chickens, and so on.  Even man’s best friend, the dog, originated from wolve

 Part 2. The Tuskless Elephants

The breeding of domestic animals was deliberate on our part. What is more surprising is the inadvertent effects that man has had on a wide variety of wild animals. I recently came across an article in Newsweek Magazine, of January 2, 2009 that describes some of these effects. The most startling one was the discovery of the tuskless elephant.

An African Elephant Without Tusks

A new Variety of Tuskless African Elephant

Elephants use their tusks to root around the ground for food, and in fighting between males during their rutting season. We also know that historically, and from the study of fossils, about two percent of elephant bulls have been tuskless. This was obviously caused by recessive mutations, which have put these animals at a disadvantage from their tusky relatives. Their loss of these useful appendages has undoubtedly been the main factor in winnowing out these genes from the population, thus keeping the number of such elephants low – until recently.

The number of tuskless elephants  has lately climbed to  38% in Gambia, and even more startlingly, to 98% in one South African population. The factor that brought about this change is the poaching of elephants for their tusks. The price on the market for tusked animals has recently risen to $10,000 per animal. That is a lot of money for a poor African, thus making these animals tempting targets. Furthermore, this is not just an African phenomenon. In Asia, female elephants do not have tusks, but the proportion of tuskless male elephants has more than doubled in recent years, rising to  greater than 90%. This has happened even on the island of Sri Lanka, where male elephants are used in the work force, and their tusks are valued as tools. As scientist, Mario Festa Bianchet of the University of Sherbrook, who has been documenting this phenomenon, pointed out, “You end up with a bunch of losers to do the breeding.” Both sexes of these elephants are also getting smaller. “These changes make no evolutionary sense,” he said.

 Part 3. A Whale of a Tale, or Floundering Around in the Mediterranean

Lest you think that these strange goings-on are confined to pachyderms, there is another, perhaps even weirder story about fish. It seems that fishermen as well as scientists have noticed that several different kinds of commercially valuable kinds of fish, such as flounder and groupers in the Mediterranean Sea, are getting smaller. Once again, the cause is painfully obvious. Fishermen, using more and more trawlers equipped with dragnets that cannot distinguish between species or size, have made it a practice to keep only the larger individuals of fish such as groupers. After sorting the fish on deck, they throw the smaller ones back, perhaps in the mistaken belief that they are being good stewards of the sea in doing so. This practice has resulted in the removal of genes for larger size from these fish populations, producing ever more smaller cod, salmon, flounder, and groupers, at least since the 1980s.

Scientists have been curious to know how far back this trend of the shrinking fish goes. After all, fishermen have been plying the Mediterranean for thousands of years. As Samir Patel reported in the January/February 2013 issue of “Archaeology,” scientists from Stanford and the University of Salento, Italy  hit upon an ingenious and novel way to find out. They went to various museums, examined mosaic tiles of fishing scenes from antiquity, and measured the fish depicted there by comparing them with objects in the mosaics whose size was known. Lo and behold, they found out that dusky groupers (Epinephelus marginatus) have been shrinking considerably for thousands of years. Even if the man-swallowing grouper in the mosaic pictured here is more than a slight exaggeration, it is obvious how far back the phenomenon of the shrinking fish goes.

Grouper Mosaic

Tile Mosaic of a Large Grouper

Man’s unknowing tinkering with nature is widespread. Big Horn sheep from Horn Mountain in Alberta, Canada have had a 25% decrease in horn size because trophy hunters  only go after the ones with imposing horns. In Australia, red kangaroos have become smaller in size because poachers target the biggest  ones for leather.

None of this information will come as a big surprise for readers of this blog. Last year, I posted a summary and analysis of an article appearing in the journal, Science, entitled “Trophic Downgrading of Planet Earth.”Its author, James Estes, along with 22 eminent collaborators, describes how apex predators, such as wolves, sharks, tigers, and lions, are being rapidly eliminated  by humans, and that this loss is having profound effects on the Earth’s ecosystems through the phenomenon of trophic cascades, by which an ever widening number of other animals and plants are being negatively effected.

Wolves' Effects on Their Enviroment

A Cascade of Effects Come About from Wolf Predation

 Part 4. How to Make More Coyotes

Doctor Robert L. Crabtree, is Research Associate Professor at the University of Montana. He is one of North America’s foremost researchers into predator/prey relationships, and an expert particularly on the coyote (Canis latrans). He has recently described a similar situation with regard to the coyote populationin the western United States. It seems that the US Wildlife Services (WS), a little known federal agency that kills millions of wild animals every year, mostly at the behest of ranchers and farmers, has unknowingly  gone into the coyote growth business. Apparently most of WS ‘s “predator control” programs are indiscriminate, in the sense that the animals killed are probably not the offending ones. (The same is true for wolves. Their haphazard removal by WS and others is grimly reminiscent  of the slaughter of Greek villagers in WW II by SS troops, in retaliation for partisan attacks on German soldiers. Most of the villagers killed were not the same people as the partisans, but the act satisfied the blood lust for revenge on all Greeks).

A trappers Idea of "Fair Chase."

Trapped and Attacked

Crabtree reports that coyote populations compensate powerfully for reductions in their populations, and WS ‘s widespread control measures (traps, poison, explosives, shooting from the air, etc.) only increase immigration, reproduction, and survival of remaining coyotes. He makes the following observations:

(1) These control campaigns result in immediate immigration into the control area by lone animals and/or invasion by other neighboring coyote groups.

(2) Litter size increases, probably due to better nutrition, caused by greater availability of prey, which results in higher birth rates and better pup survival.

(3) There is recruitment of adults from outside sources into the pack. This situation results in a doubling or tripling of the number of hungry pups to feed, and recruitment of larger and more available prey (usually sheep) to do so. Therefore, these control measures result in the opposite effect from that wanted, with more attacks on domestic animals (Note: coyotes are responsible for over 60% of livestock killings, while wolves account for less than 0.1% This means that for every sheep killed by wolves, 600 are killed by coyotes. The constant clamor by ranchers to WS and state authorities to kill more wolves is not exactly cost-effective, but what the heck, its not the ranchers, but the tax payers who are paying for this).

(4) Coyotes (and also wolves), learn what constitutes appropriate prey when they are taught as pups by adult pack members. The removal of these adults by control actions makes the pups’ education more problematical.

(5) Reduction in coyote population by control methods results in more females becoming breeders. This increases the number of pups in the ensuing generation.

(6) Removal of coyotes from a pack results in a reduction of the average age of pack members, so that more of them are reproductively active.

(7) Reduction in pack size also induces more young adults not to disperse, but to remain and become permanent pack members. Either that, or they secure breeding positions in the exploited area.

Coyotes Find a Way to Increase Their Numbers

The Wiley Coyote Outsmarts the US Wildlife Services

It is clear from these examples how humans can inadvertently and mistakenly have profound effects on the genetics and behavior of wild animal populations, and that much of the time these effects are either unintended or even contrary to the hoped-for results.

 Part 5. Of Wolves and Men

This returns us to the wolves. In 1996, wolves were reintroduced in the West. It was hoped at that time, that wolves would resume their natural role in our forests as top predators, bringing more balance into western ecosystems. At their peak, in 2011, the three states of Idaho, Montana, and Wyoming had a combined wolf population of 1,804 animals. Adding in the Great Lakes states’ wolf population, there are about 4,800 wolves in this country. At first glance this might sound like a lot of animals, but compared with other predators in the US, such as black bears (630-725,000)  and mountain lions (24-36,000) , prey such as elk (1 million) and white tailed deer (30 million), as well as domestic livestock (169 million),  it is a proverbial drop in the bucket.

Wolves were removed from the Endangered Species list in 2011. Since that time each of the three western states have instituted wolf hunting seasons unlike those for most other wild creatures except those considered varmints, such as coyotes and prairie dogs. For instance, Idaho’s season is yearlong, thus overlapping the wolves’ breeding and denning seasons. Methods of killing wolves have been expanded to trapping, use of snowmobiles,  electronic wolf calls, along with WS ‘s shooting them from airplanes. How has Idaho’s wolf management plan fared so far?

I was struck by a recent report from Idaho Fish & Game (IF&G) on wolves in Idaho. IDF&G stated that  the wolf population there at the end of 2012 was 683 wolves, a decrease of 11% from 2011. Extrapolating from the numbers in the report, only one pack in two has a breeding pair. (I must add the caveat that wild animal populations are notoriously hard to count and IDF&G terms these numbers minimum ones). These figures are in contrast to most wolf populations that I know of, including those in Canada’s Algonquin Park and in YS, in which each pack usually  has at least one breeding pair.

Furthermore, 70 wolves were killed by hunters in Idaho’s Panhandle. One of the main reasons given by IDF&G for institution of a wolf hunting season was to decrease livestock depredation by wolves. Yet, there has never been a case of livestock depredation by wolves in northern Idaho. I do not know for certain what has led to these skewed numbers, but the year-long hunting season, together with a limit of six wolves per hunter (which is to be raised this year to ten per hunter) with no upper limit on the number of wolves to be killed, may have damaged both the physical and social structure of these wolf packs.

Wolves are an extremely social species, and the complexity of their interactions is rivaled only by that of ourselves and ants. Within most packs there is a network of adults, sub adults, breeders, hunters, pups, and their caretakers (usually the sub adults). Intricate vocalizations, smells, and body language help them to communicate and coordinate with each other. Teaching and learning appropriate wolf  behavior is an important pack function. For example, it is the sub adults who usually teach the pups what is appropriate prey. Therefore the wolves grow up being attracted to elk or deer as the case may be, and not to cattle, sheep, or human beings.

I, along with many wolf biologists, believe that an intact and healthy wolf pack is one of the most important keys to low livestock depredation. One way to test a hypothesis, such as the importance of an intact wolf pack to their appropriate choice of prey, is to examine the effects of damaging that structure. There is an unplanned, inadvertent experiment going on in these three states now with increased hunting and “control” actions considerably lowering the numbers within, ages, and mix of wolves in  these packs. In the next few years, we should be able to see the results of this “unnatural” experiment. What sort of effect will these haphazardly reduced wolf populations have on livestock numbers and comparisons of wolf numbers to depredations? Will the reduction in wolf numbers lead to inbreeding and development of birth defects as it has in Isle Royale NP and Scandinavia?  This is one experiment that I wish was not taking place.

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.

Scientists debate number of wolves needed for species’ survival

 

Scientists debate ‘magic number’ of wolves needed for species' survival

[To my knowledge, this is the first article in the media to address from a scientific point of view the important issue of how many wolves are needed for a viable population. Chaney points out that according to the Conservation Biology 50/500 rule, from 2,000 - 5,000 wolves are needed in the Northern Rockies to insure a population with sufficient genetic diversity.

He also points out that the areas chosen for reintroduction, Idaho, Montana, and Wyoming, are artificial, ignoring the fact that wolves regularly move back and forth between these states and Canada. 

He looks at the much cited 1987 restoration goal of 150 wolves per state, and bluntly labels it as a dishonest political, and not a scientific number. Ed Bangs, the retiring Wolf Coordinator for USFW has admitted as much in a recent interview.

Finally, I would be remiss in not stating that Chaney's enlightening article appears to have come too late to save Northern Rockies wolves. As most readers know, they have been removed from the protection of the ESA. Idaho's and Wyoming's stated plans for them, will basically lead to either their total extermination or to their reduction to a few struggling packs and lone wolf wanderers, that will have little or no effect on the ecosystem and will be seldom even glimpsed in our forests.]

by Ken Fischman

By ROB CHANEY of the Missoulian | Posted: Sunday, May 22, 2011 7:00 am 

Conservation groups and the federal government continue to disagree how many gray wolves are needed in the Northern Rockies to ensure the species’ survival. National Park Service photo

One of the biggest arguments left unresolved by last year's wolf lawsuit was the most obvious: How many wolves are enough?

The U.S. Fish and Wildlife Service took the gray wolf off the endangered species list in 2009, with the caveat that at least 150 wolves and 15 breeding pairs endure in each of the three states in the northern Rocky Mountain population (Montana, Idaho and Wyoming).

Recent surveys found at least 1,700 wolves in that area – more than enough to justify delisting.

But a coalition of environmental groups sued the government, claiming those numbers were wrong. To survive and thrive, they argued, the population needed at least 2,000 and preferably 5,000 wolves.

FWS biologists said they used the best available science to pick their number. Coalition members cited the well-established rules of conservation biology to justify their threshold. While the scientists dueled, U.S. District Judge Donald Molloy decided the case on a technicality and Congress reversed him with a budget rider. Wolves in the Northern Rockies are now delisted, but almost nobody's happy.

*****

Over the past decade, biologists have sought a "magic number" that would simplify endangered species debates. In 2010, an Australian team led by Lochran Traill of the University of Adelaide published a study declaring 5,000 was the population size required to prevent any species' extinction.

"We don't have the time and resources to attend to finding thresholds for all threatened species," Traill told Science Observer Magazine. "(T)hus the need for a generalization that can be implemented across taxa (classes of animals and plants) to prevent extinction."

But another group of U.S. Forest Service researchers along with American and British professors warn that a simple tool may be a flawed tool. While they agree that an easily understood standard helps persuade judges or members of Congress of the need for action, the 5,000 figure doesn't add up. Their paper will be published in the journal Trends in Ecology and Evolution.

"It's natural for any policy maker and practitioner to look for ways of simplifying the overwhelming process of endangered species management," said Greg Hayward of the Forest Service's Alaska Region Office. "If that worked, it would be a delightful world to live in. But if you're really going to do anything positive, in terms of turning around the situation for these species, going for that simple rule of thumb isn't going to help."

Both sides use a lot of math to make their points. Traill and company looked at 1,198 species with a computer model that calculated how many of each would be needed for the plant or animal to survive in the long term. In particular, the study looked at how many are needed to ensure a species doesn't in-breed itself into extinction.

That's key because one requirement to getting off the endangered species list is a population big enough to guarantee genetic diversity. Earthjustice attorney Doug Honnold relied on that in his argument to Molloy, to show why the wolf should remain a listed species.

"If you're talking about genetics, then there are some basic genetic principles that apply across all species," Honnold said. "It's been documented with every species that's been studied."

Honnold referred to what's called the "50-500 rule" which states you need at least 50 breeding-age females of a species for short-term survival or 500 for the long term. In the case of wolves, there's usually only one breeding female in a pack of four to 10 wolves, so the total population number balloons to 2,000-5,000.

*****

The "magic number opponents" respond that genetics isn't everything. In the case of wolves, where might that 2,000-5,000 figure apply? Do we need a minimum viable population in the three states where wolves were reintroduced back in 1995? Or should the figure be spread across the six-state area now delisted by congressional fiat (adding Utah, Washington and Oregon to Montana, Idaho and Wyoming)? Does it count the Canadian wolves that have relations with American packs along the international border?

"Under the Endangered Species Act, we sort of ignore other segments of populations that are outside the United States," said Hayward's colleague, Steven Beissinger of the University of California-Berkeley. "In the case of the paper we did, one thing we found was, the particular technique people used to come up with this minimum number was very context-specific."

In other words, each animal needs its own formula. Passenger pigeons had different lifespans and breeding rates than wolves. They could fly across continents at will, while wolves may be stymied by freeways. Passenger pigeons were, in fact, the most abundant land bird in the continental United States – 3 billion to 5 billion individuals – before the population crashed between 1870 and 1890. [ note: Here I disagree with the reporter. The passenger pigeon population did not crash. It was deliberately exterminated, using the most atrocious means imaginable.]

Science rarely gets to be just science. Lots of scientific reasons justify the wolf's presence on the landscape: It reduces elk populations, which in turn improves the plant communities along streams, which brings back songbirds and beavers.

But reduced elk numbers aggravate a hunting community that's invested millions of dollars to improve elk habitat. Wolves also have proved a poster target for politicians who want to leash the Endangered Species Act.

Natural Resources Defense Council staff scientist Sylvia Fallon said the U.S. Fish and Wildlife Service knew it would face public resistance if it proposed reintroducing lots of wolves, so it picked a deliberately low 150-per-state figure to get the reintroduction in play.

"They (FWS biologists) say they came up with that number in consultation with scientists, but they never said who they were," Fallon said. "It was some guesswork factoring in social and political considerations at the time, what would be acceptable to the states and the public."

FWS attorneys rejected that claim in their court briefs, but they never got to have the argument in Molloy's courtroom. Without ever discussing what an appropriate number should be, the judge only said the federal government illegally used state boundaries to divide a natural population.

*****

Beissinger suggested a better target in the search for the elusive magic number. Instead of a unified field theory of how many of a species is needed to survive, we humans should settle on what risk factor we're willing to work with, he said.

"In my profession, we don't have a single standard that's been set for what degree of risk we're willing to accept for a species to go extinct," he said. "I could make a calculation for a species and say nine times out of 10, it would be viable there, for 50 years. Would that be good enough, or would you want a 95 percent chance, or an 80 percent chance? But it's too naive to use just measures of population size and come up with some rule of thumb whether a population is safe or not."

Reporter Rob Chaney can be reached at 523-5382 or at rchaney@missoulian.com.

Note: some passages were bolded by KF for emphasis

 

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.