Guest essay by Eric Worrall
Birds were amongst the most successful survivors of the Cretaceous-Paleogene extinction event which wiped out the dinosaurs, but researchers claim they won’t be able to cope with the ferocious 1-2C / century pace of the current warming period.
Past climate change pushed birds from the northern hemisphere to the tropics
by University of Cambridge
JUNE 10, 2019…
The researchers, from the Universities of Cambridge and Oxford, applied climate and ecological modelling to illustrate how the distribution of major bird groups is linked to climate change over millions of years. However, while past climate change often occurred slowly enough to allow species to adapt or shift habitats, current rates of climate change may be too fast for many species, putting them at risk of extinction. The results are reported in Proceedings of the National Academy of Sciences.
“Palaeontologists have documented long-term links between climate and the geographic distributions of major bird groups, but the computer models needed to quantify this link had not been applied to this question until now,” said Dr. Daniel Field from Cambridge’s Department of Earth Sciences, the paper’s co-lead author.
For the current study, the researchers looked at ten bird groups currently limited to the tropics, predominantly in areas that were once part of the ancient supercontinent of Gondwana (Africa, South America and Australasia). However, early fossil representatives of each of these groups have been found on northern continents, well outside their current ranges.
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Read more: https://phys.org/news/2019-06-climate-birds-northern-hemisphere-tropics.html
The abstract of the study;
Climatic shifts drove major contractions in avian latitudinal distributions throughout the Cenozoic
Erin E. Saupe, Alexander Farnsworth, Daniel J. Lunt, Navjit Sagoo, Karen V. Pham, and Daniel J. Field
Many higher level avian clades are restricted to Earth’s lower latitudes, leading to historical biogeographic reconstructions favoring a Gondwanan origin of crown birds and numerous deep subclades. However, several such “tropical-restricted” clades (TRCs) are represented by stem-lineage fossils well outside the ranges of their closest living relatives, often on northern continents. To assess the drivers of these geographic disjunctions, we combined ecological niche modeling, paleoclimate models, and the early Cenozoic fossil record to examine the influence of climatic change on avian geographic distributions over the last ∼56 million years. By modeling the distribution of suitable habitable area through time, we illustrate that most Paleogene fossil-bearing localities would have been suitable for occupancy by extant TRC representatives when their stem-lineage fossils were deposited. Potentially suitable habitat for these TRCs is inferred to have become progressively restricted toward the tropics throughout the Cenozoic, culminating in relatively narrow circumtropical distributions in the present day. Our results are consistent with coarse-scale niche conservatism at the clade level and support a scenario whereby climate change over geological timescales has largely dictated the geographic distributions of many major avian clades. The distinctive modern bias toward high avian diversity at tropical latitudes for most hierarchical taxonomic levels may therefore represent a relatively recent phenomenon, overprinting a complex biogeographic history of dramatic geographic range shifts driven by Earth’s changing climate, variable persistence, and intercontinental dispersal. Earth’s current climatic trajectory portends a return to a megathermal state, which may dramatically influence the geographic distributions of many range-restricted extant clades.
Read more (paywalled): https://www.pnas.org/content/early/2019/06/04/1903866116
Unfortunately the full study is paywalled, but I think we get the idea.
Frankly I don’t buy it. Whatever we’re doing to the climate, the impact of a gigantic meteor which wiped out pretty almost every animal over 55lb probably produced a more abrupt change to global habitats.
Other more recent climate shifts such as the Toba Eruption 75,000 years ago, which may have caused a volcanic winter, were likely a little more abrupt than anything which has occurred in the last few centuries.
I live on the edge of the tropics, I see shifts in bird populations every year – sometimes a few extreme tropics species turn up, then disappear the next year. Sometimes we see the occasional cold climate seagull, but they never stick around.
My point is, birds are always probing the edge of their range. A claim that birds can’t adapt fast enough to survive our gradual modern warming in my opinion is utterly implausible.
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“The beak of the finch”. Forced evolutionary (selective) change to a species’ population can occur over a very short time period. Nature, you so cool.
Every single Heinrich and Dansgaard–Oeschger event of the past 80000 years has produced climate change about 10 times faster than we’re now experiencing and of about 10 times the magnitude. Rates of change were degrees per decade.
Bond, et al., in (1999) The North Atlantic’s 1-2 kyr Climate Rhythm’ Relation to Heinrich Events, Dansgaard/Oeschger Cycles and the Little Ice Age in “Mechanisms of Global Climate Change at Millennial Time Scales” Peter U. Clark, Robert S. Webb, and Lloyd D. Keigwin, eds
show that D/O cycles have persisted at lower amplitude throughout the “unusually stable” Holocene climate, with the LIA the most recent cooling event of the cycle.
They finish this way: “Finally, if we are correct that the 1-2 kyr cycle is a persistent feature of the climate, at least in the North Atlantic, then one conclusion seems inescapable. Independent of any anthropogenic forcing, the North Atlantic’s climate eventually will shift (or in fact may be shifting now) toward the warm phase of the cycle. That shift will be superimposed upon and, therefore, may modulate higher frequency climate variability in the North Atlantic such as the North Atlantic Oscillation. If that is true, efforts to predict future climate trends in the North Atlantic must take into account the nature and origin of the 1-2 kyr climate cycle.”
Honest scientists whose work has been ignored by the consensus climatology poobahs.
The best that can be said about the current warming is that it’s solved the problem of providing steady jobs for the truly incompetent.
🤷♂️ Wohda thunk? CliSci is just stealth minimum guaranteed income.
I guess that too many people don’t have faith in evolution, because evolution would ensure species could adapt to a changing environment.
In sweden we see birds fly south every year in autumn, to escape the cold winter.
We have no idea why, in spring the following year, they come back.
Because they’ve eaten out the southlands.
Birds seem to like hotter weather – Brazil has over 1800 recorded and described species, Colombia has over 1900. Of course in the mountains of the Andes the temperatures and climate do vary – but if birds had trouble adapting to hot weather, you would not see them in these numbers in these places. And many birds fly from warm to cold places and back in their migrations with no real problems due to temperature changes AT ALL.
Any supposed signal of “climate change” or “global warming” caused by Man, is completely overwritten by the noise, the natural variability of the climate and weather from day to day, year to year and decade to decade. The idea that a fraction of a degree change per year, and maybe 1 degree C in the next 100 years, could cause extinctions is not something even a birdbrain could believe!
So…these climate professionals never heard of the Younger Dryas? Now that was sudden!
Wikipedia: The Younger Dryas was the most recent and longest of several interruptions to the gradual warming of the Earth’s climate since the severe Last Glacial Maximum, c. 27,000 to 24,000 years BP. The change was relatively sudden, taking place in decades, and it resulted in a decline of 2 to 6 degrees Celsius (3.6 to 10.8 degrees Fahrenheit) and advances of glaciers and drier conditions, over much of the temperate northern hemisphere.
Jan
A good example of completely trivial results being presented as something earth-shaking by maximal use of colorful graphics and climate models.
Everybody with some knowledge of avian evolution knows about this. Yes, currently tropical birds once had a larger distribution, yes the change to a colder climate in early Oligocene and from middle Miocene onwards caused a retreat from higher latitudes. So what is new? Nothing really.
And I don’t give much for their “ecological modelling”. It is apparently purely climatological, taking no account of biotic conditions and dispersal barriers which are both of great importance. And their models could certainly use a bit of tweaking. For example Coliidae (mousebirds) are found far outside their modelled range in Africa.
There is not the slightest hint of any new knowledge. For example of the ten families treated only one (Trogonidae) is found more or less throughout the tropics. All the others are more or less restricted, Todidae is found only in the West Indies, Nyctibiidae, Steatornithidae and Cariamidae only in South America, Musophagidae and Coliidae only in Africa, Leptosomidae only on Madagascar, Podargidae in South Asia and Australasia and Anseranatidae only in Australia. Why is this so, since they were all once more widespread in now temperate zones? I don’t know, and apparently the climate models don’t either.
However they only touched relatively lightly on the doom-and-gloom aspect:
“While explicit predictions are beyond the scope of the present work, our conclusions would seem to suggest that climatic changes over the coming decades and centuries may induce major distributional changes across the avian tree of life, as has been suggested recently for corals in the marine realm. The extremely rapid pace of anthropogenic climate change, however, may instead make it more likely that major groups with restricted distributions are driven to extinction in situ. Unraveling the relative likelihood of these outcomes will be an important goal of future work in avian biogeography and macroecology.”
They might have taken comfort in the fact that nearly every existing bird species has survived about 50 glaciations and interglacials, and that the avifauna of e. g. Minnesota was exactly zero just 15,000 years ago when it was covered by sever hundred meters of ice.
Note to Eric Worrall:
“Birds were amongst the most successful survivors of the Cretaceous-Paleogene extinction event which wiped out the dinosaurs”
Birds ARE dinosaurs. And while they are a most successful group today, they just barely survived the K/P extinction. There was a weird and wonderful variety of birds in the Late Cretaceous, of which a very few fairly closely related (neornithine) species, probably less than ten, survived. It is this that make bird systematics such a mess. Nearly all bird families differentiated at essentially the same time in the Early Paleocene from these very few species, making it virtually impossible to work out their relationships.
Anseranatidae would have been one of those surviving lineages and if the Magpie Goose is limited to the more tropical areas of Australia now, then that is entirely due to overhunting in the south where they were once common. One of the striking characteristics of the Australian avifauna is how homogenous it is – outside of rainforest specialists many species have very broad and flexible distributions (with some minor species/subspecies geographical variants depending on the current fad). Relatively large birds and relatively few major geographical barriers I suppose. Anyway, they seem quite capable of finding the resources they need and unlikely to be affected much by shifts of a few degrees in mean temperature.
Another strange aspect is how many black and white bird species live here. Perhaps, these pied birds are threatened and that could be modelled into another paper.
Probably not. Anseranatidae is one more of all those Paleocene groups. Galliformes and Anseriformes may have separated in the Late Cretaceous though.
But you are right that the Magpie Goose was common as far south as Victoria in the nineteenth century. This is another chronic fault of modellers. They have no historical knowledge and assume that current ranges are 100% natural and due to climate.
More rubbish from duff researchers pretending to be scientists. Hopefully, some day they will run out of duff ideas; or maybe the money will run out.
Those birds look more like the King Parrots that we see here in Victoria. They have the long tails too.
We also get black cockatoos, sulphur-crested cockatoos, crows, magpies, currawongs, blue wrens, blackbirds (Hi pals from England!), crimson rosellas, lorikeets, eastern rosellas and the rainbow ones too. There are other sorts that sometimes call in, like corellas and galahs. I reckon our place is a bird paradise; there is no shortage at all around here.
There is no shortage of insects and spiders or worms…no wonder the birds like it here!
Rainbow ones…meaning rainbow lorikeets.
Anyway Eric, apologies if I’m wrong; it’s hard to see them properly through the foliage…that’s my excuse.
Definitely rainbows. Very adaptable. I don’t remember them when I was a kid in South east Aust (cool temperate) Now they are everywhere. So the range seems to have extended from subtropics to all the way down here in the last few decades. (it has nothing to do with them escaping heat)
Yes, definitely Rainbow Lorikeets – probably the Australian bird that has most taken to humans and used us to its great advantage. We even established a population in Perth for them. King Parrots are less gregarious (usually just a small family group unless there is heavy feeding) and more solid in their colour patterns – red and green mostly – and far less garrulous. Kings just whistle and cluck, Rainbows screech and chatter.
Galahs and Corellas are great adapters….you can now find them on the beach scratching around among gulls
And they like to have fun
Only the most intelligent animals do things “for fun”. Most large parrots are quite smart.
“Tropical Birds will Fail to Adapt to Global Warming”
They certainly will if they get slashed by a wind turbine or fried to death by a solar concentrator.