# Thread: WWF Study on animal declines

1. ## WWF Study on animal declines

From the CBC

Well over half the world's population of vertebrates, from fish to birds to mammals, have been wiped out in the past four decades, says a new report from the World Wildlife Fund.

Between 1970 and 2014, there was 60 per cent decline, on average, among 16,700 wildlife populations around the world according to the 2018 edition of the Living Planet Report released Monday.
I've been reading about this on a variety of online sources, but still found the news summaries confusing. When they say 60%, do they mean 60% of species or 60% of all animals, or what.

I had to go dig out the WWF Technical Supplement to the report for an answer.

Does the trend in the global LPI mean we have lost 60% of all animals?

Although the LPI uses time-series of either population size, density, abundance or a proxy of abundance, the overall trend calculated represents an average trend in population change and not an average of total numbers of individual animals or species lost. Figure 1 explains this difference using three example populations of three different species, all of which declined but by different
percentages. The tables show that although the average percentage change is 60%, the total number of animals in the three combined populations has not declined by this much.
So, as best as I can understand it, for each of the 4005 species in their survey, they calculated (estimated?) the change in population (number of animals), and the 60% is the average of all those individual species changes.

Here is their description of the LPI database they use:
The Living Planet Database currently contains over 21,000 populations of over 4,200 species from around the globe. The global LPI is based on 16,704 of these populations, focusing on 4,005 species of mammals, birds, reptiles, amphibians and fish.
I think it is disturbing, however you look at it.

2. I think the CBC is taking liberties with that 'well over half of the world's population of vertebrates' statement. But yeah, very disturbing. When I read about what some folks are calling a present-day mass extinction event, I usually think a decline in the number of species of insects probably constitutes the bulk of the event. But half of the population (on average) of vertebrate species?

3. I'm guessing that the most severely affected species didn't have much population to begin with. It's very confusing.

It's difficult to say much more about this without violating the politics rules.

4. Originally Posted by geonuc
I think the CBC is taking liberties with that 'well over half of the world's population of vertebrates' statement.
I picked the CBC link because it appeared to be among the less sensational. <shrug> I haven't seen anyone do a decent analysis of this yet.

5. Okay, I guess all of you do have at least one kind of point in your favor when you tell me how much better the world was when you were kids...

6. Originally Posted by KaiYeves
Okay, I guess all of you do have at least one kind of point in your favor when you tell me how much better the world was when you were kids...
I would not think that (the world is both better and worse), but it makes me sad that we are not leaving you a purely better one.

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This seems realistic. When you look at the human population growth that has occurred during that time. The amount of wildlands (good wildlife habitat) converted into farmland (moderate habitat for wildlife), the amount of farmland converted to urban/suburban. The proliferation of roads and associated roadkill, habitat fragmentation, blocking of migration routes.

I am 47 years old. I grew up about 60 miles from where I now live. When I was about 25 years old I moved away for better job opportunities and spent about 20 years moving all around and not living here. Then three years ago I moved back. The change in that 20 years is extraordinary. Not too many wildlands lost, but vast areas of farmland that once supported deer, coyotes, quail, pronghorn, and other wild animals are now suburbs with just a few coyotes scrounging around the edges. Lots of lost wildlife.

And that's just here in the U.S., with our relatively mild population growth. Go into some of the nations that had much greater population growth, especially those that had political/social instability and warfare that allowed poaching to flourish, and they got hit even harder. I was a Peace Corps Volunteer back in the late 1990's. The nation in which I served now has a population about 35% above what it was when I lived there (and increased 4-fold during the timeframe in the WWF study), and went through a civil war in which poaching went unchecked in the Wildlife Reserves and National Parks. More forested areas converted to rangeland, more rangeland converted to farming, farmland converted to housing and industry. More roads, wider roads, with more vehicles that go faster.

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Originally Posted by Swift
From the CBC

I've been reading about this on a variety of online sources, but still found the news summaries confusing. When they say 60%, do they mean 60% of species or 60% of all animals, or what.

I had to go dig out the WWF Technical Supplement to the report for an answer.

So, as best as I can understand it, for each of the 4005 species in their survey, they calculated (estimated?) the change in population (number of animals), and the 60% is the average of all those individual species changes.

Here is their description of the LPI database they use:

I think it is disturbing, however you look at it.
Very disturbing. I wonder if they included feral cats. We now have about 60 million of those in the United States. I also wonder if there is another group of species that have been shown increasing. I know there are many more large bird populations, deer, wolves, cougars, large snakes, alligators and other animals in the United States than there were when I was young. Not to mention a large increase in trees.

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Overall bird populations are down in the U.S. - this link is to a popular news outlet rather than a science journal, but they are reporting data from Partners in Flight, which is a well respected consortium of wildlife biologists:

Bird populations in steep decline in North America, study finds

North America has more than a billion fewer birds than it did 40 years ago, with the snowy owl and the chimney swift just two of the better-known species in dramatic decline across the continent, a recent survey has found.

The Partners In Flight report concludes that urbanization, growth in agriculture and possibly even climate change have driven the decline in North American landbird populations, a category that excludes ducks and other waterfowl.

The total number of continental landbirds stands at about 10 billion, down from about 11.5 billion in 1970. The study's authors – a range of academic, activist and government bodies in Canada and the United States – list 86 of North America's roughly 450 breeding species as vulnerable, with some populations expected to be halved in a matter of decades.
Forty Percent of the World’s Bird Populations Are in Decline, New Study Finds

About one in eight bird species is threatened with global extinction due to factors such as the expansion of agriculture, logging, invasive species, hunting, and climate change, according to a new report from the conservation group BirdLife International. Overall, 40 percent of the world’s 11,000 bird species are in decline.

The report, The State of the World’s Birds, compiled every five years, finds that the populations of even once-widespread, easily recognizable species — including puffins, snowy owls, and turtle doves — are rapidly declining and facing global extirpation.

“The data are unequivocal,” Tris Allinson, BirdLife’s senior global science officer and editor of the new report, said in a statement. “We are undergoing a steady and continuing deterioration in the status of the world’s birds. Threats driving the avian extinction crisis are many and varied, but invariably of humanity’s making.”
It may not limited to vertebrates, a number of reports are showing declines in insect abundance, especially pollinator species:

As Insect Populations Decline, Scientists Are Trying to Understand Why

Worldwide, a 2014 summary of global declines in biodiversity and abundance estimated a 45 percent drop in the abundance of invertebrates, most of which are insects. And many individual species and species groups are declining or even being threatened with extinction, from bumblebees in Europe and the United States to fungus weevils in Africa.

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feral cats kill about 20 billion mammals per year in the US. Including about 3 billion bird. There was at one time an interesting article about the chinese fisheries. They also kill the predator fish, so their fisheries always have plenty of fish.

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12. Not all mammals are going away. Some are moving in with us. (If putting out a bird feeder means I see hawks, I'm doing it.)

http://rspb.royalsocietypublishing.o.../1890/20182120

Prey abundance and urbanization influence the establishment of avian predators in a metropolitan landscape

Jennifer D. McCabe, He Yin, Jennyffer Cruz, Volker Radeloff, Anna Pidgeon, David N. Bonter, Benjamin Zuckerberg
Published 7 November 2018. DOI: 10.1098/rspb.2018.2120
Proceedings of the Royal Society B

Urbanization causes the simplification of natural habitats, resulting in animal communities dominated by exotic species with few top predators. In recent years, however, many predators such as hawks, and in the US coyotes and cougars, have become increasingly common in urban environments. Hawks in the Accipiter genus, especially, are recovering from widespread population declines and are increasingly common in urbanizing landscapes. Our goal was to identify factors that determine the occupancy, colonization and persistence of Accipiter hawks in a major metropolitan area. Through a novel combination of citizen science and advanced remote sensing, we quantified how urban features facilitate the dynamics and long-term establishment of Accipiter hawks. Based on data from Project FeederWatch, we quantified 21 years (1996–2016) of changes in the spatio-temporal dynamics of Accipiter hawks in Chicago, IL, USA. Using a multi-season occupancy model, we estimated Cooper's (Accipiter cooperii) and sharp-shinned (A. striatus) hawk occupancy dynamics as a function of tree canopy cover, impervious surface cover and prey availability. In the late 1990s, hawks occupied 26% of sites around Chicago, but after two decades, their occupancy fluctuated close to 67% of sites and they colonized increasingly urbanized areas. Once established, hawks persisted in areas with high levels of impervious surfaces as long as those areas supported high abundances of prey birds. Urban areas represent increasingly habitable environments for recovering predators, and understanding the precise urban features that drive colonization and persistence is important for wildlife conservation in an urbanizing world. [text behind paywall]

https://phys.org/news/2018-11-woodla...an-buffet.html
News article on same, more detail.

13. Originally Posted by Roger E. Moore
Not all mammals are going away. Some are moving in with us. (If putting out a bird feeder means I see hawks, I'm doing it.)
Erm, hawks are not mammals. Just FYI.

14. Originally Posted by Noclevername
Erm, hawks are not mammals. Just FYI.
Picky, picky, picky.

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Originally Posted by Roger E. Moore
Not all mammals are going away. Some are moving in with us. (If putting out a bird feeder means I see hawks, I'm doing it.)
That's true. The common species become more common, the rare species become more rare or extinct. Widespread species (habitat generalists) extend their ranges even more, geographically limited species (habitat specialists) become even more restricted or extinct. Some people call it the Homogenocene.

16. So, years ago I lived in a very high-end neighborhood where houses went for a minimum of \$500,000 or so. As upscale as you could get for Louisville KY. We lived next to a golf-course lake.

The subdivision was built over farmland and forest. The animals moved away, then returned. In the time I was there, we had: white-tailed deer, coyotes (could tell by scent), herons (many species), frogs, red foxes, skunks, copperheads (killed a 4' long one), chipmunks, squirrels, rabbits (nests of them everywhere), raccoons, feral cats, every sort of small bird, Canada geese, mallards, bats, and heaven knows what else. Termite mounds were everywhere. Carpenter ants ate up the trees.

17. Research showing that many mammals are on their way out, and humans hold the door open for them.

https://phys.org/news/2018-11-human-...on-crisis.html

Human footprint driving mammal extinction crisis

November 9, 2018, University of Queensland

Human impacts are the biggest risk factor in the possible extinction of a quarter of all land-based mammals, according to a University of Queensland study. Researchers compared a 16-year trend in the global human footprint with the extinction risk of around 4500 land-based mammal species.

================== link to original paper

http://www.nature.com/articles/s41467-018-07049-5
(entire paper)

Changes in human footprint drive changes in species extinction risk

Moreno Di Marco, Oscar Venter, Hugh P. Possingham & James E. M. Watson
Nature Communicationsvolume 9, Article number: 4621 (2018) Nov 5, 2018

QUOTES: Species are disappearing at rates that are 1000 times faster than those registered in the fossil record, and accurate predictions of extinction risk are necessary to anticipate declines under past, current, and projected levels of human pressure. Understanding the relationship between changes in human pressures and the decline of individual species is necessary for identifying those species at highest risk, and for prioritising the actions and policies required to combat their decline. Comparative extinction risk modelling, which builds on the relationship between species threat status, their life histories, and the pressure mapped within their ranges, is increasingly used to predict the risk of extinction. This approach allows inferring the extinction risk of a large number of species based on readily available data, and predictions can be updated more often than expert-based assessments, given the substantially lower resources requirement. However, a major limitation in these analyses is the absence of a link to spatial and temporal changes in human pressure and how these lead to change in the risk of species declines. This is further complicated by two types of change in human pressure, the change in extent of pressures (e.g. road building in a new area), and the intensification of existing pressures (e.g. increase in deforestation rates). The missing linkage between pressure and extinction risk means comparative extinction risk analysis has struggled to inform policy and management.

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Originally Posted by Roger E. Moore
Research showing that many mammals are on their way out, and humans hold the door open for them.

https://phys.org/news/2018-11-human-...on-crisis.html
un
Human footprint driving mammal extinction crisis

November 9, 2018, University of Queensland

Human impacts are the biggest risk factor in the possible extinction of a quarter of all land-based mammals, according to a University of Queensland study. Researchers compared a 16-year trend in the global human footprint with the extinction risk of around 4500 land-based mammal species.

================== link to original paper

http://www.nature.com/articles/s41467-018-07049-5
(entire paper)

Changes in human footprint drive changes in species extinction risk

Moreno Di Marco, Oscar Venter, Hugh P. Possingham & James E. M. Watson
Nature Communicationsvolume 9, Article number: 4621 (2018) Nov 5, 2018

QUOTES: Species are disappearing at rates that are 1000 times faster than those registered in the fossil record, and accurate predictions of extinction risk are necessary to anticipate declines under past, current, and projected levels of human pressure. Understanding the relationship between changes in human pressures and the decline of individual species is necessary for identifying those species at highest risk, and for prioritising the actions and policies required to combat their decline. Comparative extinction risk modelling, which builds on the relationship between species threat status, their life histories, and the pressure mapped within their ranges, is increasingly used to predict the risk of extinction. This approach allows inferring the extinction risk of a large number of species based on readily available data, and predictions can be updated more often than expert-based assessments, given the substantially lower resources requirement. However, a major limitation in these analyses is the absence of a link to spatial and temporal changes in human pressure and how these lead to change in the risk of species declines. This is further complicated by two types of change in human pressure, the change in extent of pressures (e.g. road building in a new area), and the intensification of existing pressures (e.g. increase in deforestation rates). The missing linkage between pressure and extinction risk means comparative extinction risk analysis has struggled to inform policy and management.
It is depressing to see the destruction of natural habitat and to know the forces that are causing this are unstoppable except by some monster of humanity or microbiology.

19. Choices, not forces, caused this. Sometimes ignorant or unknowing choices, but human decisions nevertheless.

We're only capable of mitigating the damage done at this point, but the available solutions are generational. And the kids growing up to come into power tomorrow seem to be more aware of the necessities of this situation than the current crop of TPTB.

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Originally Posted by Noclevername
Choices, not forces, caused this. Sometimes ignorant or unknowing choices, but human decisions nevertheless.

We're only capable of mitigating the damage done at this point, but the available solutions are generational. And the kids growing up to come into power tomorrow seem to be more aware of the necessities of this situation than the current crop of TPTB.
The End is Nigh, Repent and Mend Your Ways. Yup, got it.

21. Originally Posted by 7cscb
The End is Nigh, Repent and Mend Your Ways. Yup, got it.
Well, yes, actually. But without the sarcasm.

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Originally Posted by crescent
Overall bird populations are down in the U.S. - this link is to a popular news outlet rather than a science journal, but they are reporting data from Partners in Flight, which is a well respected consortium of wildlife biologists:

Bird populations in steep decline in North America, study finds

Forty Percent of the World’s Bird Populations Are in Decline, New Study Finds

It may not limited to vertebrates, a number of reports are showing declines in insect abundance, especially pollinator species:

As Insect Populations Decline, Scientists Are Trying to Understand Why
If feral cats kill about 3 billion birds in the US per year, this explains a lot since you are stating there are only about 11 billion birds in the US.

23. I read that many insects, beetles, suffered because of this summer's heat waves, they lost fertility and populations have declined, this will affect the birds and the rest of the food chain. If global warming means more extremes like that, which it does, the decline of insects in some regions could be an unrecognised source of trouble.

24. Originally Posted by Copernicus
If feral cats kill about 3 billion birds in the US per year, this explains a lot since you are stating there are only about 11 billion birds in the US.
Feral cats are a problem, but in your multiple posts you seem to be implying that this is the primary cause of the declines in animal populations discussed in the OP. I think that does a disservice to many other causes, including habitat loss, climate change, pollution, other invasive species (besides cats), and consequences of human overpopulation (such as overfishing and land use practices).

25. I visited an Owl sanctuary. In the UK we are losing owls because of those factors, loss of habitat, decline in small mammals, but there is a quaint reversal. Thanks to Harry Potter there are many owl breeders, (not always a good sign). However many new owners chose the formidable eagle Owl, native to UK but rare. But these owls get too big so they get released (illegally) and being a top predator they survive. With five foot wingspan they can take a cat or a fox and their numbers are increasing in several counties here.

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Originally Posted by Swift
Feral cats are a problem, but in your multiple posts you seem to be implying that this is the primary cause of the declines in animal populations discussed in the OP. I think that does a disservice to many other causes, including habitat loss, climate change, pollution, other invasive species (besides cats), and consequences of human overpopulation (such as overfishing and land use practices).
Hi Swift, I think if you look at post 18 I was including habitat loss as contributor
I have my doubts about climate change causing species loss as tropical climates offer the most life and most diversification of species. I am skeptical that we will be able to stop humans from taking more and more and more.

27. Originally Posted by Copernicus
I have my doubts about climate change causing species loss as tropical climates offer the most life and most diversification of species.
You can have any doubts you like, but they are not supported by the data.

Impacts of climate change on biodiversity and ecosystem services
(looks like a nice review, with references)
In the last 100 years average global temperature has increased by 0.74°C, rainfall patterns have changed and the frequency of extreme events increased. Change has not been uniform on either a spatial or temporal scale and the range of change, in terms of climate and weather, has also been variable.

Change in climate has consequences on the biophysical environment such as changes in the start and length of the seasons, glacial retreat, decrease in Arctic sea ice extent and a rise in sea level. These changes have already had an observable impact on biodiversity at the species level, in term of phenology, distribution & populations, and ecosystem level in terms of distribution, composition & function.
Most of these observed changes are modest, which is possibly due to the limited change in climate that has occurred. However, future projected changes in climate are much larger. IPCC AR4 suggests that approximately 10% of species assessed so far will be at an increasingly high risk of extinction for every 1°C rise in global mean temperature, within the range of future scenarios modelled in impacts assessments (typically <5°C global temperature rise). Aquatic freshwater habitats and wetlands, mangroves, coral reefs, arctic and alpine ecosystems, and cloud forests are particularly vulnerable to the impacts of climate change. Montane species and endemic species have been identified as being particularly vulnerable because of narrow geographic and climatic ranges, limited dispersal opportunities, and the degree of non-climate pressures. Potential impacts of climate change on genetic diversity are little understood, though it is thought that genetic diversity will increase the resilience of species to climate change.
Tropical climates may be the most diverse (I'm not completely sure of that), but it is a mistake to think that currently temperate areas will turn into diverse tropical climates. For one thing, rainfall patterns may not support such an ecosystem.

But one of the biggest problems is that the rapidity of the changes in climate are happening faster than animals (and plants) can adapt to the changes. And if they can't adapt, they will die.

28. I agree with Swift. First of all diversity is a sign of a mature ecosystem with many of its niches filled and a balance in the food cycles for population numbers. If the environment changes, and global warming is not a steady warming but includes bigger swings of the seasons, then some species will not adapt fast enough as I mentioned in a report of beetles suffering major decline because of two heat waves this last summer, and their fertility collapsed. This disturbs the ecosystem and there will be both population explosions and collapses. This happens all the time but there is plenty of evidence that it is much worse in the last decades than before. The ocean changes are favouring jelly fish and harming some fish. It's a problem!

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If one looks at geometric progression one finds that changes to the environment occur much faster from species change than anything climate can do. That is why I bring up the feral cat. There are 60 million in the US. But one could bring up any number of invasive species that multiply like crazy and are impossible to stop once they start. Kudzu, garlic mustard, whatever caused american elm, american chest nut, or any number of other tree species to be decimated. These affects are so monstrously fast compared to any global climate change affects that global climate change affects would be but a butterfly wing flap in comparison. One single bacteria could theoretically multiply to the mass of the universe within a week. These are all processes that happen every day, millions of times over.
The feral cat example is relevant because feral cats kill 3 billion birds out of 20 billion every year. That is 15 percent. If birds did not reproduce so fast the bird populations would be wiped out in less than 7 years.

30. yes but feral cats are an example of human modified food chain. Cats would be prey to dogs, stoats, eagles, and bigger cats if they were present. Just as introduced rats on small islands with no larger predators, wipe out the birds.

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