How Science Works - Tracking How Great Tits In An Oxfordshire Wood Are Responding To Climate Change

Wytham Wood, Oxfordshire, UK

Early morning, Wytham Wood

The great tits in this Oxford wood are adapting their breeding times as climate changes – here’s how

This article caught my eye because it concerns the birds in a wood which is local to me - Wytham Wood, near Oxford, to which I have licensed access. This is reputedly the most intensively studied area of woodland in the world, belonging, as it does, to Oxford University.

Wytham Woods form an iconic location that has been the subject of continuous ecological research programmes, many dating back to the 1940s. The estate has been owned and maintained by the University of Oxford since 1942. The Woods are often quoted as being one of the most researched pieces of woodland in the world, and their 1000 acres are designated as a Site of Special Scientific Interest.

The wooded parts of the Wytham Estate comprise ancient semi-natural woodland (dating to the last Ice Age), secondary woodland (dating to the seventeenth century), and modern plantations (1950s and 60s). The fourth key habitat is the limestone grassland found at the top of the hill. Other smaller habitats include a valley-side mire and a series of ponds.

The site is exceptionally rich in flora and fauna, with over 500 species of plants, a wealth of woodland habitats, and 800 species of butterflies and moths.

https://www.wythamwoods.ox.ac.uk/

Through intensive observation over successive years, researchers are able to measure changes in behaviour of species such as the Great Tit, Parus major with some of the best examples of observational biology in the form of research papers. For example, a few years ago a team of researchers showed that the British race of Great tits were diverging from their European relatives with changes in the beaks probably reflecting the fact that we in Britain provide feeding stations for birds to sustain them through the winter much more frequently than other Europeans, so the British Great tits are evolving so they can get the food in the bird feeders in British gardens.

In the following article, ecologist, David López Idiáquez, a Postdoctoral Research Associate in Behavioural and Evolutionary Ecology, University of Oxford, explains how their research is measuring how Great tits are responding to climate change. His article is reprinted here from The Conversation under a Creative Commons license, reformatted for stylistic consistency, with photographs from Internet sources:

How Evolution Works - Choas, Catastrophe and Tipping Points

The fitness landscape of hyphae showing that natural shapes are constrained by a tipping point.

Credit: Maxim Ohairwe

Hyphal mycelium.

credit: Maxim Ohairwe.

Researchers Discover Evolutionary “Tipping Point” in Fungi

An interesting paper has just been published which illustrates how chaos theory and catastrophe theory are related and explain the appearance of 'punctuated equilibrium' in the fossil record. It concerns the small environmental change that can trigger a large phenotypic change in the growth and shape of fungal hyphae.

One of the more annoying things to emerge in evolutionary biology during the last 30 years or so is the idea that 'Punctuated Evolution' (PE) somehow either falsifies or replaces Darwinian evolution as the explanation for biodiversity. Of course, it does neither. The term was invented by Stephen J Gould and Niles Eldredge, to explain the appearance of sudden change in the geological column, where species appear to remain unchanged for prolonged periods of time, then change, in what, with the compression of time in the geological column, looks like instantaneously.

Sadly, the term quickly became entangled with both American nationalism and creationism; the latter because it appears to refute the person whom creationists think is the arch prophet of the 'evil' of evolution - Charles Darwin, the leading figure in creationist demonology - as though the entire body of evolutionary biology hangs on the authority of one 19th century biologist; the former because it appears to have replaced one of the most famous scientific theories with one 'discovered' by Americans, so asserting American pre-eminence in science.

Tell me about 'Punctuated Equilibrium'; who popularized the idea and the arguments for and against it. Punctuated equilibrium is a theory in evolutionary biology that suggests that the tempo of evolution is not constant but rather characterized by periods of relatively rapid change (punctuation) interspersed with prolonged periods of stability (equilibrium). This concept was popularized by paleontologists Niles Eldredge and Stephen Jay Gould in their 1972 paper "Punctuated Equilibria: An Alternative to Phyletic Gradualism."

Arguments for punctuated equilibrium include:

1. Fossil Record: Eldredge and Gould argued that the fossil record often shows long periods of stasis, where species exhibit little morphological change over millions of years, followed by relatively rapid bursts of evolutionary change when new species appear.
2. Lack of Transitional Forms: They also pointed out that the fossil record frequently lacks the transitional forms predicted by gradualism, which suggests that evolution may occur in more rapid bursts.
3. Genetic Mechanisms: Some genetic models also support the idea of punctuated equilibrium, suggesting that small populations undergoing rapid change due to factors like genetic drift and founder effects can lead to rapid speciation.

Arguments against punctuated equilibrium include:

1. Lack of Evidence: Critics argue that punctuated equilibrium is based more on interpretation of the fossil record rather than direct evidence from genetic or ecological studies.
2. Sampling Bias: Some scientists suggest that the apparent gaps in the fossil record may be due to incomplete sampling rather than actual periods of stasis.
3. Mechanistic Explanation: Critics also question the mechanisms underlying punctuated equilibrium, arguing that it may be difficult to explain how rapid evolutionary change occurs in the absence of significant environmental pressures or genetic changes.

Overall, punctuated equilibrium remains a subject of debate within evolutionary biology, with proponents arguing that it provides a more accurate description of patterns of evolution observed in the fossil record, while critics suggest that it may overemphasize the importance of long periods of stasis and rapid bursts of change.

Creationism in Crisis - How A Change In The Envionment Can Faciltate Migration and Divergence

Figure 1. Flows of non-native insects between North America (NA), Europe (EU), and Australasia (AU). Numbers indicate the total count of species established from donor to recipient, with flow widths being proportional to these counts. Overlapping flows on the donor side indicate the fraction of species that established in both recipient regions.

European insects spread across the world. Was it because settlers carried plants?

It's an observable, and often regrettable fact of biology that the majority of invasive species tend to be from Europe into North America and Australia and not vice versa. That’s not to say there are no migrations the other way, but the distribution is highly asymmetric, so is unlikely to be due to chance alone.

There have been several attempts to explain this in terms of the North American and Australian environment being inherently more amenable to invasion, and the European environment being less so. However, historically, Europe has been repeatedly invaded by insect species from Asia, so the latter explanation is unlikely.

It is generally assumed that insects are spread inadvertently by trade in goods, when insects 'stow away' in packages, the holds of ships, etc., but research led by Dr. Rylee Isitt of the University of New Brunswick, and published in the journal NeoBiota, shows that after accounting for patterns of international trade, the number of insects that have spread from Europe into North America, Australia, and New Zealand far exceeds expectations.

The question is then, is there something different about European insects that makes them better at invading new territories; are they more numerous? Or is there something else at work here?

The same research found no evidence for these ideas:

Figure 2. Cumulative discoveries (observed and modelled) and establishments (modelled) of non-native insects exchanged between Europe (EU), North America (NA), and Australasia (AU) versus cumulative import value (inflation-corrected to 2020 British pounds sterling, billions), 1827–2014. Alternating background shading indicates decadal increments, with shading omitted prior to the 1940s for clarity.

So, what's going on?

Dr. Isitt and collaborators have proposed that the abundance of European insect invaders may be a result of deliberate introductions of non-native plants into Europe's colonies. Plants introduced into European colonies could have promoted the spread of European insects into North America and Australia by two different means.

This is, of course, consistent with a basic prediction of the Theory of Evolution by Natural Selection. If an environmental change creates an opportunity for a species to expand its territory, then it will expand into that new territory, where if there is any competition, natural selection will determine the outcome. However, if the change in the environment is the introduction of a food resource that was previously absent, there is unlikely to be much competition, so the invasive species gets a free ride.

And of course, as Europeans have colonised new lands such as North America, Australia and New Zealand, so they have taken their traditional staple food plants with them, created a perfect environment for European insects to tag along and become established just as the human colonists and their plants have.

The research team have published their findings in NeoBiota:

Abstract

The geographical exchange of non-native species can be highly asymmetrical, with some world regions donating or receiving more species than others. Several hypotheses have been proposed to explain such asymmetries, including differences in propagule pressure, source species (invader) pools, environmental features in recipient regions, or biological traits of invaders. We quantified spatiotemporal patterns in the exchange of non-native insects between Europe, North America, and Australasia, and then tested possible explanations for these patterns based on regional trade (import values) and model estimates of invader pool sizes. Europe was the dominant donor of non-native insect species between the three regions, with most of this asymmetry arising prior to 1950. This could not be explained by differences in import values (1827–2014), nor were there substantial differences in the sizes of modelled invader pools. Based on additional evidence from literature, we propose that patterns of historical plant introductions may explain these asymmetries, but this possibility requires further study.

Introduction

Non-native insects have been implicated in displacing native species, altering the composition of ecological communities, damaging economically important trees and food crops, vectoring diseases, and more (Kenis et al. 2009; Bradshaw et al. 2016). An intriguing aspect of insect invasions is that some regions appear to have donated disproportionately more non-native insects during biotic exchange than others. For example, considerably more phytophagous forest insects have invaded North America from Europe than the reverse (Niemelä and Mattson 1996.1), and Europe has contributed a large fraction of New Zealand’s non-native insect fauna (Edney-Browne et al. 2018). Consequently, the question of why such asymmetries may occur has fascinated ecologists for decades, with several mutually compatible hypotheses offered: (1) differences in the magnitude of invasion vectors, such as international trade, may lead to differences in the arrival and establishment rates of non-native species; (2) differences in the size of potential invader pools may drive differences in the numbers of species being donated to other regions; (3) environmental differences (e.g., climate and availability of host plants) in recipient regions may promote or inhibit invasion; and (4) biological traits of insects native to some regions may make them better at invading or competing than insects native to other regions (Vermeij 1991, 1996; Niemelä and Mattson 1996; Visser et al. 2016.1).

The latter two hypotheses are often tested on a single insect order or guild and at smaller spatial scales (e.g., Rigot et al. 2014; Guyot et al. 2015; Rassati et al. 2016.2), but less commonly on multiple insect orders and multiple geographical regions. Testing them requires regional knowledge of the nature of recipient environments and their ecological communities, and of the biological traits of the invaders, information that is often available only for certain regions or certain insect groups/guilds. The former two hypotheses are more approachable, given the availability of datasets on international trade, regional insect richness, and modelling approaches that can estimate invader pool sizes.

Our research goals were firstly to test for the existence of asymmetries in the cumulative numbers of insect invaders, across all taxa, exchanged between three world regions of interest: North America, Europe, and Australasia (limited to Australia and New Zealand). These regions were chosen due to their histories of anthropogenic interactions and exchange of species, existing literature suggesting asymmetrical exchange of insects between them (see above), and the availability of data. Secondly, if clear asymmetries were found, we aimed to determine if they could be explained by differences in propagule pressure (using the value of international trade as a proxy) or by differences in estimates of invader pool sizes. We did not statistically test hypotheses (3) and (4), above, but considered them as possible explanations for asymmetries that could not be explained by hypotheses (1) and (2).

Isitt R, Liebhold AM, Turner RM, Battisti A, Bertelsmeier C, Blake R, Brockerhoff EG, Heard SB, Krokene P, Økland B, Nahrung HF, Rassati D, Roques A, Yamanaka T, Pureswaran DS (2024)
Asymmetrical insect invasions between three world regions. NeoBiota 90: 35-51. https://doi.org/10.3897/neobiota.90.110942

This is an open access article distributed under the terms of the CC0 Public Domain Dedication.

It's good to see how the basic principles of environment-led evolution (which often starts with migration into new territory) underpins the observable phenomenon of invasive insect species and what governs their movements. Earth is, of course, a dynamic and changing place where these sorts of migrations in response to environmental change have been going on for hundreds of millions of years. Recently however, Man has become a major factor in this process, the consequences of which are still being played out. One thing we can be sure of though is that there is no place for supernatural magic in the explanation for it.

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Ten Reasons To Lose Faith: And Why You Are Better Off Without It

This book explains why faith is a fallacy and serves no useful purpose other than providing an excuse for pretending to know things that are unknown. It also explains how losing faith liberates former sufferers from fear, delusion and the control of others, freeing them to see the world in a different light, to recognise the injustices that religions cause and to accept people for who they are, not which group they happened to be born in. A society based on atheist, Humanist principles would be a less divided, more inclusive, more peaceful society and one more appreciative of the one opportunity that life gives us to enjoy and wonder at the world we live in.

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What Makes You So Special? From The Big Bang To You

How did you come to be here, now? This books takes you from the Big Bang to the evolution of modern humans and the history of human cultures, showing that science is an adventure of discovery and a source of limitless wonder, giving us richer and more rewarding appreciation of the phenomenal privilege of merely being alive and able to begin to understand it all.

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Thank you for sharing!

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Creationism in Crisis - How Elephants Got Their Trunks and Tusks 20 Million Years Before 'Creation Week' - No Magic Required

Artist's impression of Platybelodon grangeri

Credit: Tim Bertelink via Wikimedia (CC BY-SA 4.0)

Platybelodon grangeri (artist's impression)

How shifting climates may have shaped early elephants’ trunks | For the press | eLife

As expected of scientific research papers, this one deals with events that occurred in that vast expanse of time before creationists think Earth was created, when 99.97% of Earth's history occurred.

This one, published open access in eLife, explains how the ancestors of modern elephants and their recently extinct relatives, the mammoths, got their long flexible trunks and used them for their unique feeding method.

The paper by lead author, Chunxiao Li, and colleagues from the Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China, and including Burt Wolff of the Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, USA and Fajun Sun of the Department Environmental Science & Technology, University of Maryland, MD, USA, "combines multiple analyses to reconstruct feeding behaviours in the extinct longirostrine elephantiforms - elephant-like mammals characterised by elongated lower jaws and tusks."

It seems that, as they grew larger, for reasons not yet fully understood, but possibly to give a larger 'vat' in which to ferment their high-cellulose diet, these early ancestors of the elephants had to evolve a longer jaw to reach the grasses and shrubs on which they grazed. The trunk extended as part of this process of facial elongation. This in turn created the opportunity for the end of the truck to play a part in holding the plants as they were cut off by the incisor teeth at the end of the lower jaw. This was more of an advantage in the open grasslands that Platybelodon inhabited, so, when climate change meant loss of habitat and eventual extinction for the two related gomphotheres, Platybelodon's prehensile trunk gave it enough advantage to survive.

A press release by eLife explains the research and its significance for understanding how elephants got their trunks:

Creationism in Crisis - Research Shows How Environment Drives Evolution - No Magic Required

Raining Cats and Dogs: Research Finds Global Precipitation Patterns a Driver for Animal Diversity

A team of researcher from Utah University's Department of Watershed Sciences in Quinney College of Natural Resources and the Ecology Center, led by Jaron Adkins, has investigated why there is a rich diversity of species in some areas and a paucity of species in others. Not surprisingly, given what we know of how diversity evolves due to environmental selectors, they found a close link between diversity and the environment, especially rainfall, and the result of rainfall, or a lack of it - plant growth.

Climate Change News - As Earth's Temperature Rises, Humanity is Slowly Grasping the Fact That There is No Planet B

Increasingly dangerous wildfires are just one consequence of climate change. Here, a man watches in 2013 as the Springs fire in California approaches.

Credit: David McNew Getty Images

6 reasons why global temperatures are spiking right now

A Pharmacy shop sign displays the outside temperature of 46 Celsius degrees (114.8 F) in downtown Rome, July 18, 2023.

AP Photo/Domenico Stinellis

As I have commented before, probably the most dangerous delusion fostered by the Abrahamic religions, is that Earth was given to humankind for our exclusive use and that we are being watched over by a benevolent magic guardian in the sky who will ensure that no long-term harm will come to us and our planet. This delusion could well result in us making this planet, our life-support system in the cosmos, uninhabitable by all but a small number of species such as bacteria and cockroaches.

Fundamentalist 'loving' Christians jibber excitedly about the 'end times', looking forward to the day when their imaginary friend comes to Earth and kills everyone who disagrees with them so they can have everything for themselves, but the only end times we face are the end times for all of us, just assuredly as a space man systematically destroying his own spaceship.

So, what is causing the record temperatures we are experiencing this year, where records are not only being broken almost every day, but being broken by record margins? In the following article, reprinted from The Conversation, Andrew King, Senior Lecturer in Climate Science, The University of Melbourne gives six reasons for these record temperatures. His article is reprinted under a Creative Commons licence, reformatted for stylistic purposes:

Pollution News - How Road Vehicle Tyres Are Polluting Our Waterways

Tyre wear particles are considered by environmental scientists to be one of the most significant sources of microplastics in the ocean.

Photograph: Ian Nicholson/PA

Bit by bit microplastics from tyres are polluting our waterways – Griffith News

Back in the late 1960's, when I was a student at Oxford Polytechnic (Now Oxford Brookes University) studying for an HNC in Applied Biology, one of the modules (on which apparently the National Council for Academic Awards (NCAA) insisted) was 'General Studies', i.e., anything which broadened our education away from the narrowness of a specialised subject, such as Applied Biology.

Part of that was an assignment to investigate an aspect of man-made environmental pollution, Rachal Carson's 'Silent Spring' being a recent publication and a nascent green movement beginning to emerge. The subject I decided on was to investigate what happened to the millions of tons of vulcanized rubber from road vehicle tyres that needed to be replaced annually because tyres wore away on the roads. It stood to reason that that rubber either entered the atmospheres as dust, or, more likely, got washed off the roads and into road-side ditches and eventually into the waterways and from there to the sea.

The question was, what effect did this fine rubber dust have on the environment and how much of it ended up in the food chain?

I was shocked to discover, after several days searching the literature available to me in the college library (if only we had had the Internet in those days!) that there was not a scrap of scientific data on the subject. There were no published papers on the question whatsoever. Either no-one had thought it worth investigating, no-one had identified the problem, or no-one was prepared to fund the research. And yet millions of tons of vulcanized rubber were being turned into tyres and from then into rubber dust on our roads, and it was all going somewhere, but no-one knew where!

In desperation, and with a project to complete, I abandoned my research and instead looked at the environmental effects of DDT, then extensively used as an insecticide, and about which some alarming news was emerging - extermination of brown pelicans in American lakes treated with DDT to kill mosquitoes, because DDT is adsorbed onto particulate matter which is ingested by the small organisms eaten by fish and so concentrated up the food chain, at the apex of which were brown pelicans; loss of peregrine falcons because DDT reduced egg shell thickness, leading to a loss of broods, again the result of DDT being concentrated up the food chain and killing the apex predators.

So, news that, some 54 years later, researchers at Griffin University, Australia, have published a paper in Environmental Science & Technology, dealing with a closely related problem - the problem of microplastics and tire [sic] wear products in urban stormwater.

Sadly, the research paper is behind a paywall, but a Griffin University news release explains the research and its significance:

Creationism in Crisis - Urban Great Tits Have Beome Paler Than Their Rural Relatives

Urban (left) and rural (right) great tits, Parus major

Photo: Caroline Isaksson

European great tit, Parus major.

Source

Urban great tits have paler plumage than their forest-living relatives | Lund University

In an example of how the environment, and in this case probably the availability of different food items, can cause changes on which natural selection can act, a study by an international team or reserchers led by Pablo Salmón of Lund University, Sweden, has shown that great tits, Parus major living in an urban environment have paler breasts than those living in a forest environment.

Although this is probably not an evolutionary change, i.e., a change in the frequency of alleles in the population gene pools, as the cause is probably dietary difference, it illustrates how an environmental change can produce changes in features on which natural selection can act to bring about true evolutionary changes, and so begin the process of allopatric speciation.

Of course, there will be creationists who will misrepresent the scientific fact of evolution, either deliberately, or mendaciously in order to mislead others, who will dismiss this as "not evolution", not for the reason given above but because "they're still great tits/still birds" and haven't grown a new structure or turned into an unrelated taxon.

The research is explained in a Lund University press release:

Creationism in Crisis - Are Red Kangaroos Evolving in the Absence of Dingoes?

Slideshow code developed in collaboration with ChatGPT3 at https://chat.openai.com/

Red kangaroos, Osphranter rufus
Evolving in the absence of dingoes?

'An exciting possibility': scientists discover markedly different kangaroos on either side of Australia's dingo fence

If you change an organism's environment, the Theory of Evolution by Natural Selection (TOE) predicts that the organism will evolve to fit into that changed environment. One such change could be the removal of an apex predator, as happened when humans erected the 'dingo fence', stretching more than 5,600 Km (about 3,500 miles) across Australia in the 1950, but was in a state of disrepair until 1975, which is thus the effective start of environmental isolation southeast of the fence.

The purpose of the fence was to protect domestic sheep from dingoes, Canis dingo, the wild Australian canid and only Australian placental mammal other than bats. Dingoes have been Australia's apex predator for some 10,000 years, maybe longer, so have been an important part of the ecosystem and the main, if not only, predator on red kangaroos, Osphranter rufus since then.

So, when wildlife to the southeast of the 'dingo fence' had their apex predator removed, the TOE predicts that there should be observable evolutionary change, and this is what a team of scientist led by Dr Rex Mitchel of the College of Science and Engineering, Flinders University, Adelaide, South Australia may have found when they studied the Red Kangaroos either side of the fence. Although, as they point out, evolutionary change in about 45 years, or about 17 red kangaroo generations, would be unusual and, with a limited dataset more work is needed to check that other factors are not the cause of the observed changes, for example, reduced stress in the protected area.

Four of the team: Vera Weisbecker, Associate Professor, Flinders University; Corey J. A. Bradshaw, Matthew Flinders Professor of Global Ecology and Models Theme Leader for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders University; Frédérik Saltré, Research Fellow in Ecology for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders University, and Dr D Rex Mitchell, have written about their research in The Conversation.

Their article is reprinted here under a Creative Commons licence, reformatted for stylistic consistency:

Published: May 31, 2023 9.07pm BST

‘An exciting possibility’: scientists discover markedly different kangaroos on either side of Australia’s dingo fence

Image source: Shutterstock

Vera Weisbecker, Flinders University; Corey J. A. Bradshaw, Flinders University; Frédérik Saltré, Flinders University, and Rex Mitchell, Flinders University

Australia’s dingo fence is an internationally renowned mega-structure. Stretching more than 5,600 kilometres, it was completed in the 1950s to keep sheep safe from dingoes. But it also inadvertently protects some native species.

This makes the fence an unintentional experiment in the relationship between predators and prey. Our new research examined how the fence affects a favourite prey of the dingo: red kangaroos.

We found young kangaroos on the side exposed to dingoes grew more quickly than their protected counterparts. This has potentially big repercussions for the health of these juveniles.

The merits of the dingo fence are hotly debated, and there have been calls to pull it down or move it. That’s why we must seek a better understanding of how the fence affects the animals that live along it.

Australia’s dingo fence runs for more than 5,600 kilometres.

Image source: Shutterstock

‘Stressful’ lives

The dingo fence, formally known as the “wild dog barrier fence”, runs through Queensland, New South Wales and South Australia. It protects sheep and cattle to the southeast.

Extensive fencing can fragment habitats and disrupt ecosystems. Maintaining the fence costs about A$10 million per year. For these and other reasons, some have suggested the fence be pulled down.

But how would removing the fence affect kangaroos that have lived without dingoes for up to 70 years? Our research sought to answer this question.

We assessed 166 red kangaroos from two isolated populations on either side of the fence in far northwest NSW. We did this using data collected as part of a licensed shooting program. We compared population size, age structure, sex ratio, growth rate and skull shape.

We expected kangaroos north of the fence – those hunted by dingoes – to differ from their dingo-free cousins to the south. That’s because their lives are more stressful, especially for young kangaroos and females that are killed by dingoes more often than adult males.

Killing dingoes is the only way to protect livestock, right? Nope

Female and young red kangaroos are targeted by dingoes.

Image source: Shutterstock

What we found

As anticipated, we found more young and female kangaroos in the dingo-protected population south of the fence. But the story is more complex than that.

Young kangaroos south of the fence, up to about the age of four years, grew more slowly than those in the north. They were substantially smaller and lighter than their dingo-exposed counterparts.

This raises an exciting possibility: that the growth of kangaroos south of the fence has slowed in the absence of the dingo threat.

But maybe there was just more plant food available in the north, where there are fewer kangaroos compared to the south. Was this the reason the northern kangaroos grew more quickly?

As it turns out, no. We assessed the vegetation on each side of the fence using a decade of satellite measurements. We found there was probably less, not more, food overall for kangaroos in the north compared to the south.

More detailed investigation is needed into whether the types of plants differed on each side of the fence. But our results suggest the different growth rates were driven by predators, not food availability.

The dingo fence from space: satellite images show how these top predators alter the desert

There was probably less vegetation north of the dingo fence than in the south

Image source: Shutterstock

This raises important questions

The differences between populations are even more striking considering the dingo fence in the area we studied was in disrepair until 1975. Before then, dingoes and kangaroos probably moved freely. So the changes we observed could have come about in as little as 17 kangaroo generations.

This would be unusually fast for an evolutionary adaptation. Instead, we suspect it’s the result of a more immediate response to the absence of dingoes, such as lower concentrations of stress-related hormones. These affect the health of mammals, and might have affected kangaroo growth rates in this case.

After about the age of four, the protected kangaroos had caught up and were the same size as their unprotected counterparts. But the unprotected kangaroos would have invested a lot more bodily resources into growing so quickly.

This would have left less energy for the animals to develop important functions such as their immune or reproductive systems. Or they might have had less fat reserves.

Conversely, protected kangaroos might have been healthier, or more fertile, because of their slower growth rates.

New DNA testing shatters 'wild dog' myth: most dingoes are pure

The research raises questions about how mammals respond to changes such as the absence of dingoes.

Image source: Shutterstock

Understanding the mammal response

Our study involved only a single sample at one point in time. But it’s the first to comprehensively assess differences in a dingo prey species on either side of a fence.

Our results provide an insight into how prey populations might fare if the dingo fence is removed. But the implications are potentially even broader.

We must now investigate whether other native mammal species share similar differences across the fence. If so, this could help us predict how animals elsewhere in Australia are coping with rapid environmental change.
Vera Weisbecker, Associate Professor, Flinders University; Corey J. A. Bradshaw, Matthew Flinders Professor of Global Ecology and Models Theme Leader for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders University; Frédérik Saltré, Research Fellow in Ecology for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders University, and Rex Mitchell, Postdoctoral Fellow, Flinders University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Published by The Conversation.
Open access. (CC BY 4.0)

The researchers' findings are published, open access in the Journal of Mammology:

Abstract

Decommissioning the dingo barrier fence has been suggested to reduce destructive dingo control and encourage a free transfer of biota between environments in Australia. Yet the potential impacts that over a century of predator exclusion might have had on the population dynamics and developmental biology of prey populations has not been assessed. We here combine demographic data and both linear and geometric morphometrics to assess differences in populations among 166 red kangaroos (Osphranter rufus)—a primary prey species of the dingo—from two isolated populations on either side of the fence. We also quantified the differences in aboveground vegetation biomass for the last 10 years on either side of the fence. We found that the age structure and growth patterns, but not cranial shape, differed between the two kangaroo populations. In the population living with a higher density of dingoes, there were relatively fewer females and juveniles. These individuals were larger for a given age, despite what seems to be lower vegetation biomass. However, how much of this biomass represented kangaroo forage is uncertain and requires further on-site assessments. We also identified unexpected differences in the ontogenetic trajectories in relative pes length between the sexes for the whole sample, possibly associated with male competition or differential weight-bearing mechanics. We discuss potential mechanisms behind our findings and suggest that the impacts of contrasting predation pressures across the fence, for red kangaroos and other species, merit further investigation.

Mitchell, D Rex; Cairns, Stuart C; Körtner, Gerhard; Bradshaw, Corey J A; Saltré, Frédérik; Weisbecker, Vera (2023)
Differential developmental rates and demographics in Red Kangaroo (Osphranter rufus) populations separated by the dingo barrier fence
Journal of Mammology, gyad053. DOI: 10.1093/jmammal/gyad053

Copyright: © 2023 The authors.
Published by Oxford University Press. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

Fig 1.

The dingo barrier fence extends from southeast Queensland to the Great Australian Bight in South Australia. The study location (black rectangle): Quinyambie and Mulyungarie stations are adjacent properties located on the western side of the South Australia–New South Wales border (black dotted line) and separated by the fence.

Mitchell, et. al,(2023)

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Fig 4.

Changes in cranial shape throughout ontogeny in Osphranter rufus. Orbs represent cranial shape predicted for younger individuals. Mesh represents shape predicted for older individuals. Relative braincase size and incisor size become smaller during growth.

Mitchell, et. al,(2023)

What is now needed is detailed DNA analysis of the two populations because any differences would be definitive evolutionary change.

That should be a small crumb of comfort for creationists who must continue to hope that no such differences are found in red Kangaroos or other wildlife either side if the dingo fence, but I wonder how many of them would be prepared to bet their house on the probability of none being found.

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Creationism in Crisis - Confirmation of the Role of Environmental Change in the First Mass Extinction

FSU researchers: Rapid fluctuations in oxygen levels coincided with Earth's first mass extinction - Florida State University News

Professor Nevin Kozik, PhD, of Department of Earth, Ocean and Atmospheric Science – National High Magnetic Field Laboratory, Florida State University, during fieldwork to investigate how rapid changes in marine oxygen levels may have played a significant role in driving Earth’s first mass extinction.

Fundamental to the Theory of Evolution (TOE) is the idea that environmental change causes evolutionary change, a consequence of which can be extinction, especially when change is too rapid for species to evolve adaptations to it. Environmental change can be very rapid (instantaneous in the case of a meteor strike, for example) but evolutionary change is characteristically very slow, needing many generations to produce a significant adaptation.

So, it's hardly surprising that a period of rapidly fluctuating marine oxygen levels about 443 million years ago, caused Earth's first mass extinction at the same time. Confirmation of that, and so of a prediction of the TOE, has now been produced by a team led by Florida State University (FSU) researchers.

The research depends on a fairly recent dating method for marine sediment that measures the proportion of thallium isotopes in the sediment, as explained by Owens, J.D; Neilson S.D; Horner, T.J., et al (2016)^[PDF]:

Environment News - How Many Ants Are There?

Ants following a scent trail

Earth harbours 20,000,000,000,000,000 ants – and they weigh more than wild birds and mammals combined

Many years ago, when I was a medical research technician for Oxford University, the lab I worked in suddenly had a problem with tiny yellow ants that were all over the place, so we called in a university entomologist. He identified them as pharaoh ants, a recently introduced species to the UK that was thriving in centrally-heated buildings.

We weren’t the only department with the problem because, as he explained, there was a large colony of possibly a billion individual ants somewhere in underground heating system that piped heating from a central boiler room serving many different buildings behind the Natural History and Pitt Rivers Museums, but they were harmless anyway, although it wasn't pleasant to find they'd discovered your pack of sandwiches and had laid a trail to it along which thousands were now streaming in a thin yellow line, carrying your lunch away, crumb by crumb. They especially liked ham, but wouldn't turn down cheese or egg.

We used to have a bit of fun with them, being research biologists. We would place a strip of paper across their trail and wait until they had found their way across it to pick up their trail on the other side and laid a new connecting scent trail on the paper, then we would move the paper several inches sideways and watch as they explored the paper to discover the trail across it now several inches away, cross it and then explore to find the old trail. Then we would remove the paper and watch as they still followed along where the edges of the paper strip had been to where the trail used to cross the paper strip, lay a new trail and follow back along what had been the edge of the paper to pick up their old trail. Sometimes an enterprising scout would find a shortcut and establish a new trail. In this way, we could create a complicated zig-zag trail and make them work for their free lunch! It would take them several hours to re-establish a shorter trail.

Incidentally, this also proved they were laying a trail of some sort. The trail could also be washed away with an alcohol swab, showing it was almost certainly a chemical of some sort.

But enough about the fun we had with our resident pharaoh ants.

Our billion-strong colony was a mere speck in the ocean, according to research by an Australian team. They have conservatively estimated that there are about 20 quadrillion ants alive on Earth at any one time - that's 20 followed by 15 zeros. Each of those ants will have about 250,000 brain cells alone and probably ten times as many other cells in their body. Each cell will contain hundreds, maybe thousands of proteins, each of which will need to be folded precisely to function correctly.

One of the tricks Creationists frauds fool their dupes with is to calculate how many different ways a protein can be folded then pretend to have estimated the chance of it being folded in exactly the right way to be vanishingly small, then hit their credulous audience with a false dichotomy fallacy and claim this proves the locally popular god must have arranged it.

Really? for every one of those sextillions of proteins in every one of those cells in all 20 quadrillion ants? And then there are the countless trillions of cells in other species! No wonder it doesn't have time to prevent children dying of malaria, AIDS or starvation in Africa!

You see, we can all play the big scary number tactic! But isn't it much more likely that the way proteins are folded is a function of the way they are manufactured by a cell, using nothing more complicated than the laws of chemistry and physics, than that it was all done by which ever deity the frauds are pushing, the existence of which and its modus operandum have never been demonstrated or witnessed?

So, leaving that major problem for Creations aside, how was the number, 20 quadrillion, arrived at for the Earthly population of ants, which incidentally means their combined weight of dry carbon is about 12 million tonnes, which exceeds that of all birds and mammals combined! The authors explain their methodology in an open access article in The Conversation, reprinted below under a Creative Commons license, reformatted for stylistic consistency. The original article can be read here.

Earth harbours 20,000,000,000,000,000 ants – and they weigh more than wild birds and mammals combined

Shutterstock

Mark Wong, The University of Western Australia; Benoit Guénard, University of Hong Kong; François Brassard, Charles Darwin University; Patrick Schultheiss, Julius Maximilian University of Würzburg; Runxi Wang, University of Hong Kong, and Sabine Nooten, Julius Maximilian University of Würzburg
Have you ever wondered exactly how many ants live on Earth? Possibly not, but it’s certainly a question we’ve asked ourselves.

Our research published today provides an approximate answer. We conservatively estimate our planet harbours about 20 quadrillion ants. That’s 20 thousand million millions, or in numerical form, 20,000,000,000,000,000 (20 with 15 zeroes).

We further estimate the world’s ants collectively constitute about 12 million tonnes of dry carbon. This exceeds the mass of all the world’s wild birds and wild mammals combined. It’s also equal to about one-fifth of the total weight of humans.

Eminent biologist Edward O. Wilson once said insects and other invertebrates are “the little things that run the world” – and he was right. Ants, in particular, are a crucial part of nature. Among other roles, ants aerate the soil, disperse seeds, break down organic material, create habitat for other animals and form an important part of the food chain.

Estimating ant numbers and mass provides an important baseline from which to monitor ant populations amid worrying environmental changes.

Many ant species are important seed dispersers. Here, two worker Meranoplus ants carry a seed back to their nest.

Credit: Francois Brassard

Counting the world’s ants

There are more than 15,700 named species and subspecies of ants, and many others not yet named by science. Ants’ high degree of social organisation has enabled them to colonise nearly all ecosystems and regions around the globe.

The astounding ubiquity of ants has prompted many naturalists to contemplate their exact number on Earth. But these were basically educated guesses. Systematic, evidence-based estimates have been lacking.

Our research involved an analysis of 489 studies of ant populations conducted by fellow ant scientists from around the world. This included non-English literature, in languages such as Spanish, French, German, Russian, Mandarin and Portuguese.

The research spanned all continents and major habitats including forests, deserts, grasslands and cities. They used standardised methods for collecting and counting ants such as pitfall traps and leaf litter samples. As you can imagine, this is often tedious work.

In defence of ants

A researcher installs a pitfall trap, a standard method for collecting ants that crawl across the ground surface.

Credit: Francois Brassard

From all this, we estimate there are approximately 20 quadrillion ants on Earth. This figure, though conservative, is between two and 20 times higher than previous estimates.

The previous figures employed a “top-down” approach by assuming ants comprise about 1% of the world’s estimated insect population. In contrast, our “bottom-up” estimate is more reliable because it uses data on ants observed directly in the field and makes fewer assumptions.

Our next step was to work out how much all these ants weigh. The mass of organisms is typically measured in terms of their carbon makeup. We estimated that 20 quadrillion average-sized ants corresponds to a dry weight or “biomass” of approximately 12 million tonnes of carbon.

This is more than the combined biomass of wild birds and mammals – and about 20% of total human biomass.

Carbon makes up about half the dry weight of an ant. If the weight of other bodily elements was included, the total mass of the world’s ants would be higher still.

We also found ants are distributed unevenly on Earth’s surface. They vary sixfold between habitats and generally peak in the tropics. This underscores the importance of tropical regions in maintaining healthy ant populations.

Ants were also particularly abundant in forests, and surprisingly, in arid regions. But they become less common in human-made habitats.

Our findings come with a few caveats. For example, the sampling locations in our dataset are unevenly distributed across geographic regions. And the vast majority of samples were collected from the ground layer, meaning we have very little information about ant numbers in trees or underground. This means our findings are somewhat incomplete.

Where are all the ants? World-first ‘treasure map’ reveals hotspots for rare species

The new research found ants are distributed unevenly on Earth’s surface.

Credit: Shutterstock

We all need ants

Ants also provide vital “ecosystem services” for humans. For instance, a recent study found ants can be more effective than pesticides at helping farmers produce food.

Ants have also developed tight interactions with other organisms – and some species cannot survive without them.

For example, some birds rely on ants to flush out their prey. And thousands of plant species either feed or house ants in exchange for protection, or dispersal of their seeds. And many ants are predators, helping to keep populations of other insects in check.

A purple Rhytidoponera ant carries her prey between her jaws. Many ants serve as predators that help keep populations of other insects in check.

Credit: Francois Brassard

Alarmingly, global insect numbers are declining due to threats such as habitat destruction and fragmentation, chemical use, invasive species and climate change.

But data on insect biodiversity is alarmingly scarce. We hope our study provides a baseline for further research to help fill this gap.

It’s in humanity’s interest to monitor ant populations. Counting ants is not difficult, and citizen scientists from all over the world could help investigate how these important animals are faring at a time of great environmental change.

Why tiny ants have invaded your house, and what to do about it

Mark Wong, Forrest Fellow, The University of Western Australia;
Benoit Guénard, Associate professor, University of Hong Kong;
François Brassard, PhD candidate, Charles Darwin University;
Patrick Schultheiss, Temporary Principal Investigator, Julius Maximilian University of Würzburg;
Runxi Wang, PhD candidate, University of Hong Kong,
and Sabine Nooten, Temporary Principal Investigator, Julius Maximilian University of Würzburg

Published by The Conversation.
Open access. (CC BY 4.0)

The team have published their findings in the journal PNAS. Although the main body of thr paper is behind a paywall, the abstract is pubished open access:

Significance

The astounding ubiquity of ants has prompted many naturalists to contemplate their exact number on Earth, but systematic and empirically derived estimates are lacking. Integrating data from all continents and major biomes, we conservatively estimate 20 × 1015 (20 quadrillion) ants on Earth, with a total biomass of 12 megatons of dry carbon. This exceeds the combined biomass of wild birds and mammals and equals 20% of human biomass. Ant abundance is distributed unevenly on Earth, peaking in the tropics and varying sixfold among habitats. Our global map of ant abundance expands our understanding of the geography of ant diversity and provides a baseline for predicting ants’ responses to worrying environmental changes that currently impact insect biomass.

Abstract

Knowledge on the distribution and abundance of organisms is fundamental to understanding their roles within ecosystems and their ecological importance for other taxa. Such knowledge is currently lacking for insects, which have long been regarded as the “little things that run the world”. Even for ubiquitous insects, such as ants, which are of tremendous ecological significance, there is currently neither a reliable estimate of their total number on Earth nor of their abundance in particular biomes or habitats. We compile data on ground-dwelling and arboreal ants to obtain an empirical estimate of global ant abundance. Our analysis is based on 489 studies, spanning all continents, major biomes, and habitats. We conservatively estimate total abundance of ground-dwelling ants at over 3 × 1015 and estimate the number of all ants on Earth to be almost 20 × 1015 individuals. The latter corresponds to a biomass of ∼12 megatons of dry carbon. This exceeds the combined biomass of wild birds and mammals and is equivalent to ∼20% of human biomass. Abundances of ground-dwelling ants are strongly concentrated in tropical and subtropical regions but vary substantially across habitats. The density of leaf-litter ants is highest in forests, while the numbers of actively ground-foraging ants are highest in arid regions. This study highlights the central role ants play in terrestrial ecosystems but also major ecological and geographic gaps in our current knowledge. Our results provide a crucial baseline for exploring environmental drivers of ant-abundance patterns and for tracking the responses of insects to environmental change.

Schultheiss, Patrick; Nooten, Sabine S.; Wang, Runxi; Wong, Mark K. L.; Brassard, François; Guénard, Benoit

The abundance, biomass, and distribution of ants on Earth
Proceedings of the National Academy of Sciences (2022) 119(40); e2201550119; DOI: 10.1073/pnas.2201550119

Copyright: © 2022 The authors.
Published by PNAS
. Open access
Reprinted under a Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND)

With the exception of a few nasty ants such as the vicious bullet and fire ants, most species are harmless and even beneficial. In the UK we have the very common black garden ant that, when the conditions are right in Spring and Summer - the right humidity and a high pressure weather system to help with flying - have a nuptial flight when the winged unmated females and smaller males all take flight at the same time from several different nests in the area. The males pursue the female, and the winner gets to mate with her. He then dies, as do all the others who lost the race. The female lands, sheds her wings and looks for somewhere to build a nest and start a new colony. This gives rise to panic and complaints about an invasion of 'flying ants', and the hardware shops have a run on ant power. One very silly neighbour we once had used to spray ant powder along our adjoining fence because she believed all the ants in her garden had come from ours! People even pour boiling water on them!

And yet these are harmless unless you annoy them then they can give a mild sting, more like a pinprick, really. They are incredibly useful in gardens where they account for thousands of caterpillars. Please treat them with respect. If they do come into your house, look upon them as cleaners because they'll be finding food crumbs and spilt sugar, etc. Keeping the floor and surfaces clean, and keeping food covered in sealed containers, will mean you won't get visits.

We need our ants - all 20 quadrillion of them!

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