What we know we don’t know about animal tolerances to high temperatures

30 01 2023

Each organism has a limit of tolerance to cold and hot temperatures. So, the closer it lives to those limits, the higher the chances of experiencing thermal stress and potentially dying. In our recent paper, we revise gaps in the knowledge of tolerance to high temperatures in cold-blooded animals (ectotherms), a diverse group mostly including amphibians and reptiles (> 16,000 species), fish (> 34,000 species), and invertebrates (> 1,200,000 species).

As a scientist, little is more self-realising than to write and publish a conceptual paper that frames the findings of your own previous applied-research papers. This is the case with an opinion piece we have just published in Basic and Applied Ecology1 — 10 years, 4 research papers2-5 [see related blog posts here, here, here and here], and 1 popular-science article6 after I joined the Department of Biogeography and Global Change (Spanish National Research Council) to study the thermal physiology of Iberian lizards under the supervision of Miguel Araújo and David Vieites.

Iberian lizards for which heat tolerance is known (varying from 40 to 45 °C)
 
[left, top to bottom] Iberian emerald lizard (Lacerta schreiberi, from Alameda del Valle/Madrid) and Geniez’s wall lizard (Podarcis virescens, Fuertescusa/Cuenca), and [right, top to bottom] Algerian sand racer (Psammodromus algirus, Navacerrada/Madrid), Andalusian wall lizard (Podarcis vaucheri, La Barrosa/Cádiz), Valverde’s lizard (Algyroides marchi, Riópar/Albacete), and Cyren’s rock lizard (Iberolacerta cyreni, Valdesquí/Madrid). Heat-tolerance data deposited here and used to evaluate instraspecific variation of heat tolerance3,4. Photos: Salvador Herrando-Pérez.

In our new paper, we examine how much we know and what areas of research require further development to advance our understanding of how and why the tolerance of ectotherm fauna to high environmental temperature (‘heat tolerance’ hereafter) varies within and across the Earth’s biomes. We focus on data gaps using the global database GlobTherm as a reference template (see Box 1 below).

Our three main tenets

1. Population versus species data: Most large-scale ecophysiological research is based on modelling one measurement of heat tolerance per species (typically representing one population and/or physiological assay) over hundreds to thousands of species covering broad geographical, phylogenetic, and climatic gradients.

But there is ample evidence that heat tolerance changes a lot among populations occupying different areas of the distribution of a species, and such variation must be taken into account to improve our predictions of how species might respond to environmental change and face extinction.

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Tenure-Track Professorship in Conservation and Development

26 01 2023

The Faculty for Mathematics and Natural Sciences of Humboldt-Universität zu Berlin (HU Berlin), Geography Department, has an open position for a tenure-track professorship in Conservation and Development.

Starting as soon as possible. This is a Junior Professorship (W1 level, 100%) with a tenure track to a permanent professorship (W2 level, 100%). To verify whether the individual performance meets the requirements for permanent employment, an evaluation process will be opened not later than four years of the Junior Professorship. Tenure track professors at the HU Berlin are expected to do research and teaching, as well as to be active in university administration, in the promotion of young scientists, and in acquiring leadership and management skills. The concrete requirements out of the framework catalogue will be specified in the course of the appointment process.

We seek candidates with an outstanding research record in biodiversity conservation and sustainable development, with experience in working in the Global South. Successful candidates are rooted in conservation science and must have a doctoral degree in conservation science, development geography, environmental science, political ecology or related fields. We expect a demonstrated ability to work interdisciplinary, across the social and natural sciences to understand conservation challenges and and develop solutions.

We seek individuals with the vision, leadership and enthusiasm to build an internationally recognised research program. We expect collaboration with other research groups at the department, at HU Berlin and beyond, and a commitment to promoting a positive, diverse, and inclusive institutional culture. Experience in translating conservation science into action and/or work at the science/policy interface are beneficial.

We offer a tenure-track position in an international, young and vibrant department with an excellent scientific and education track record. The successful candidate will join an interdisciplinary group of faculty focused on human-environment relations, global change, and sustainability.

The salary will be according to W1 level, and after successful tenure evaluation W2 level. Employment at HU Berlin offers all benefits of the German public service system, including health insurance, an attractive pension plan, and social benefits.

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Interrupted flows in the Murray River endanger frogs

17 01 2023

Flooding in the Murray-Darling Basin is creating ideal breeding conditions for many native species that have evolved to take advantage of temporary flood conditions. Led by PhD candidate Rupert Mathwin, our team developed virtual models of the Murray River to reveal a crucial link between natural flooding and the extinction risk of endangered southern bell frogs (Litoria raniformis; also known as growling grass frogs).

Southern bell frogs are one of Australia’s 100 Priority Threatened Species. This endangered frog breeds during spring and summer when water levels increase in their wetlands. However, the natural flooding patterns in Australia’s largest river system have been negatively impacted by expansive river regulation that some years, sees up to 60% of river water extracted for human use.

Our latest paper describes how we built computer simulations of Murray-Darling Basin wetlands filled with simulated southern bell frogs. By changing the simulation from natural to regulated conditions, we showed that modern conditions dramatically increase the extinction risk of these beloved frogs.

The data clearly indicate that successive dry years raise the probability of local extinction, and these effects are strongest in smaller wetlands. Larger wetlands and those with more frequent inundation are less prone to these effects, although they are not immune to them entirely. The models present a warning — we have greatly modified the way the river behaves, and the modern river cannot support the long-term survival of southern bell frogs.’

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Influential conservation papers of 2022

3 01 2023

Following my annual tradition, I present the retrospective list of the ‘top’ 20 influential papers of 2022 as assessed by experts in Faculty Opinions (formerly known as F1000). These are in no particular order. See previous years’ lists here: 2021, 2020, 201920182017201620152014, and 2013.


Genetic variance in fitness indicates rapid contemporary adaptive evolution in wild animals — “… this paper adds a much-needed perspective to the status of genetic diversity and adaptive potential in contemporary populations.

Habitat, geophysical, and eco-social connectivity: benefits of resilient socio-ecological landscapes — “… distinguishes four distinct but interrelated types of connectivity: landscape, habitat, geophysical, and eco-social connectivity, of which the fourth type is new. The authors discuss how these different types of connectivity are related to ecosystem services and disservices, and how they interact with each other to influence landscape sustainability issues.

Glyphosate impairs collective thermoregulation in bumblebees — “… low-dose glyphosate, combined with global increases in temperature, converge to disrupt homeostatic regulation in bee colonies. This is a crucial revelation for understanding the loss of bees across the globe, as they serve as major pollinators in nature and agriculture.

Human disturbances affect the topology of food webs — “… provides great opportunities for the study of food web structures, their dynamics and stability under different human influences.

A comprehensive database of amphibian heat tolerance — “provides estimates of amphibian upper thermal limits – a relevant trait for assessing the vulnerability of this highly-threatened group of ectotherms to rising temperatures – derived from thousands of experimental studies.”

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Children born today will see literally thousands of animals disappear in their lifetime, as global food webs collapse

17 12 2022
Frida Lannerstrom/Unsplash, CC BY

Corey J. A. Bradshaw, Flinders University and Giovanni Strona, University of Helsinki

Climate change is one of the main drivers of species loss globally. We know more plants and animals will die as heatwaves, bushfires, droughts and other natural disasters worsen.

But to date, science has vastly underestimated the true toll climate change and habitat destruction will have on biodiversity. That’s because it has largely neglected to consider the extent of “co-extinctions”: when species go extinct because other species on which they depend die out.

Our new research shows 10% of land animals could disappear from particular geographic areas by 2050, and almost 30% by 2100. This is more than double previous predictions. It means children born today who live to their 70s will witness literally thousands of animals disappear in their lifetime, from lizards and frogs to iconic mammals such as elephants and koalas.

But if we manage to dramatically reduce carbon emissions globally, we could save thousands of species from local extinction this century alone.

Ravages of drought will only worsen in coming decades.
CJA Bradshaw

An extinction crisis unfolding

Every species depends on others in some way. So when a species dies out, the repercussions can ripple through an ecosystem.

For example, consider what happens when a species goes extinct due to a disturbance such as habitat loss. This is known as a “primary” extinction. It can then mean a predator loses its prey, a parasite loses its host or a flowering plant loses its pollinators.

A real-life example of a co-extinction that could occur soon is the potential loss of the critically endangered mountain pygmy possum (Burramys parvus) in Australia. Drought, habitat loss, and other pressures have caused the rapid decline of its primary prey, the bogong moth (Agrotis infusa).

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Should we bring back the thylacine? We asked 5 experts

17 08 2022
Tasmanian Museum and Art Gallery

Signe Dean, The Conversation

In a newly announced partnership with Texas biotech company Colossal Biosciences, Australian researchers are hoping their dream to bring back the extinct thylacine is a “giant leap” closer to fruition.

Scientists at University of Melbourne’s TIGRR Lab (Thylacine Integrated Genetic Restoration Research) believe the new partnership, which brings Colossal’s expertise in CRISPR gene editing on board, could result in the first baby thylacine within a decade.

The genetic engineering firm made headlines in 2021 with the announcement of an ambitious plan to bring back something akin to the woolly mammoth, by producing elephant-mammoth hybrids or “mammophants”.

But de-extinction, as this type of research is known, is a highly controversial field. It’s often criticised for attempts at “playing God” or drawing attention away from the conservation of living species. So, should we bring back the thylacine? We asked five experts.

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Terror management

2 08 2022

As is my tendency, I like to wade carefully into other disciplines from time to time to examine what components they can bring to the conservation table. I do not profess any sort of expertise when I do so, but if I require a true expert for research purposes, then I will collaborate with said experts.

I often say to my students that in many ways, the science of sustainability and conservation is more or less resolved — what we need now is ways to manage the human side of the problems we face. The disciplines that deal with human management, such as psychology, economics, political science, and sociology, are mainly pursuits of the humanities (have I just argued myself out of a job?).

On the topic of human psychology, I think most people involved in some way with biodiversity conservation often contemplate why human societies are so self-destructive. Even in the face of logic and evidence, people deny what’s going on in front of their eyes (think anti-vaxxers, climate-change denialists, etc.), so it should be no wonder why many (most?) people deny their own existential threats. Yet, it still doesn’t seem to make much sense to us until we put the phenomenon into a psychological framework.

My apologies here to actual psychologists if I oversimplify or otherwise make mistakes, but the following explanation has done a lot for me personally in my own journey to understand this conundrum. It is also a good way to teach others about why there is so much reticence to fixing our environmental problems.

The idea is a rather simple one, but it requires a little journey to appreciate. Let’s pop back to the 1970s with the publication of Ernest Becker’s The Denial of Death, for which he won the Pulitzer Prize in 1974 (ironically, two months after his own death). In this book, Becker examined the awareness of death on human behaviour and the strategies that we have developed to mitigate our fear of it. This particular quote sums it up nicely:

This is the terror: to have emerged from nothing, to have a name, consciousness of self, deep inner feelings, and excruciating inner yearning for life and self expression — and with all this yet to die

Ernest Becker in The Denial of Death (1973)

The upshot is that we have evolved a whole raft of coping mechanisms to this personal existential dread. Some engage in overly hedonic pursuits to numb the anxiety; others try to “tranquillise themselves with the trivial”, essentially ignoring the terror, while others still manage the dread through religion and the hope of an existence beyond the mortal.

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Journal ranks 2021

4 07 2022

Now that Clarivate, Google, and Scopus have recently published their respective journal citation scores for 2021, I can now present — for the 14th year running on ConvervationBytes.com — the 2021 conservation/ecology/sustainability journal ranks based on my journal-ranking method.

Like last year, I’ve added a few journals. I’ve also included in the ranking the Journal Citation Indicator (JCI) in addition to the Journal Impact Factor and Immediacy Index from Clarivate ISI, and the CiteScore (CS) in addition to the Source-Normalised Impact Per Paper (SNIP) and SCImago Journal Rank (SJR) from Scopus. 

You can access the raw data for 2021 and use my RShiny app to derive your own samples of journal ranks.

I therefore present the new 2021 ranks for: (i) 106 ecology, conservation and multidisciplinary journals, (ii) 27 open-access (i.e., you have to pay) journals from the previous category, (iii) 64 ‘ecology’ journals, (iv) 32 ‘conservation’ journals, (v) 43 ‘sustainability’ journals (with general and energy-focussed journals included), and (vi) 21 ‘marine & freshwater’ journals.

Remember not to take much notice if a journal boasts about how its Impact Factor has increased this year, because these tend to increase over time anyway What’s important is a journal’s relative (to other journals) rank.

Here are the results:

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Best and worst countries by different environmental indicators

15 06 2022

I’ll preface this post with a caveat — the data herein are a few years old (certainly pre-COVID), so things have likely changed a bit. Still, I think the main message holds.


Many years ago, I compiled seven different national-level measures of environmental degradation to show that countries with the largest human populations, and hence, the largest economies, had done the most environmental damage — not only to their own resources, but to the world’s in general.

That last observation is important because there are really two main ways to quantify a country’s environmental performance. First, there is its relative environmental damage, which essentially means what proportion of its own resources a country has pilfered or damaged. This type of measure standardises the metrics to account for the different areas of countries (e.g., Russia versus Singapore) and how much of, say, forests, they had to start with, and what proportion of them they have thus far destroyed.

Looking at it this way, small countries with few large-scale industries came out in the lead as the least-damaged environmentally — the least environmentally damaged country according this metric is Cape Verde (followed by Central African Republic, Swaziland, Niger, and Djibouti).

However, another way to look at it is how much of the overall contribution to the world’s environmental damage each country is responsible, which of course implies that the countries with the highest amounts of resources damaged in absolute terms (i.e., the biggest, most populous ones) disproportionately contribute more to global environmental damage.

Using this absolute metric, the countries with the greatest overall damage are Brazil (largely due to the destruction of the Amazon and its other forests), the USA (for its greenhouse-gas emissions and conversion of its prairies to farmland), and China (for its water pollution, deforestation, and carbon emissions). On the flip side, this means that the smallest countries with the fewest people are ranked ‘better’ because of their lower absolute contribution to the world’s total environmental damage.

Looking more closely at how countries do relative to each other using different and more specific measures of environmental performance, the best-known and most-reported metric is the ecological footprint. This measures the ecological ‘assets’ that any particular population of people requires to produce the natural resources it consumes and to absorb its wastes.

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Fallacy of zero-extinction targets

20 05 2022

Nearly a decade ago (my how time flies*), I wrote a post about the guaranteed failure of government policies purporting no-extinction targets within their environmental plans. I was referring to the State of South Australia’s (then) official policy of no future extinctions.

In summary, zero- (or no-) extinction targets at best demonstrate a deep naïvety of how ecology works, and at worst, waste a lot of resources on interventions doomed to fail.

1. Extinctions happen all the time, irrespective of human activity;

2. Through past environmental degradation, we are guaranteed to see future extinctions because of extinction lags;

3. Few, if any, of the indicators of biodiversity change show improvement.

4. Climate change will also guarantee additional (perhaps even most) future extinctions irrespective of Australian policies.

I argued that no-extinction policies are therefore disingenuous to the public in the extreme because they sets false expectations, engender disillusionment after inevitable failure, and ignores the concept of triage — putting our environment-restoration resources toward the species/systems with the best chance of surviving (uniqueness notwithstanding).

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Bane of the bees

19 04 2022

Bees are essential for pollination, but their critical function can be perturbed by pesticides. The detrimental effects of those chemicals accumulate through a bee’s life, and become stronger if females cannot collect pollen from wildflowers.

Our childhood experiences partly determine our health, personality, and lifestyle when we are adults, and our experiences accumulate over time. Accumulation also occurs in any living being and can explain why some populations and species adapt to their environments better than others.

Migratory birds are a clear example. Thousands can travel to their breeding grounds after wintering elsewhere, and those coming from regions laden with resources (e.g., food, shelter, water) will have a greater reproductive success than those that migrated from resource-poor regions (1). In ecology, these ‘carry-over’ effects can take place between seasons, but also across the different phases of the life cycle of a plant or animal (2).

From larvae to adults

Clara Stuligross and Neal Williams have studied the carry-over effect of pesticides on the blue orchard bee Osmia lignaria in California (3). Instead of the typical hives constructed by the honey bee (Apis mellifera), solitary blue orchard bees make lines of brood cells with mud partitions, glued into holes and crevices of branches and trunks from fallen trees (see videos herehere, & here).

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A cascade of otters

4 04 2022

Carnivores are essential components of trophic webs, and ecosystem functions crumble with their loss. Novel data show the connection between calcareous reefs and sea otters under climate change.


Trophic cascade on the Aleutian Islands (Alaska, USA) linking sea otters (Enhydra lutris) with sea urchins (Strongylocentrotus polyacanthus) and calcareous reefs (Clathromorphum nereostratum). With males weighting up to 50 kg, sea otters have been IUCN-catalogued as Endangered since 2000. The top photo shows a male in a typical, belly-up floating position. The bottom photo shows live (pinkish) and dead (whitish) tissue on the reef surface as a result of grazing of sea urchins at a depth of 10 m. Sea otters are mesopredators, typically foraging on small prey like sea urchins, but their historical decline due to overhunting unleashed the proliferation of the echinoderms. At the same time, acidification and sea-water warming have softened the skeleton of the reefs, allowing for deeper grazing by sea urchins that eliminate the growth layer of living tissue that give the reefs their pinkish hue. Large extents of dead reefs stop fixing the excess in carbonic acid, whose carbon atoms sea water sequesters from the atmosphere enriched in carbon by our burning of fossil fuels. Photos courtesy of Joe Tomoleoni taken in Moss Landing – California, USA (otter), and on the Near Islands – Aleutian Archipelago, Alaska (reef).

For most, the decisions made by people we have never met affect our daily lives. Other species experience the same phenomenon because they are linked to one another through a trophic cascade.

A trophic cascade occurs when a predator limits the abundance or behaviour of its prey, in turn affecting the survival of a third species in lower trophic levels that have nothing directly to do with the predator in question (1).

Sea otters (Enhydra lutris) represent a text-book example of a trophic cascade. These mustelids (see video footage here and here) hunt and control the populations of sea urchins (Strongylocentrotus polyacanthus), hence favouring kelp forests  — the fronds of which are eaten by the sea urchins.

Removing the predator from the equation should lead to more sea urchins and less kelp, and this chain of events is exactly what happened along the coasts of the North Pacific (2, 3). The historical distribution of sea otters once ranged from Japan to Baja California through the Aleutian Islands (see NASA’s photo from space, and documentary on the island of Unimak), a sub-Arctic, arc-shaped archipelago including > 300 islands between Alaska (USA) and the Kamchatka Peninsula (Russia), extending ~ 2000 kilometres, and having a land area of ~ 18,000 km2.

But the fur trade during the 18th and 19th centuries brought the species to the brink of extinction, down to < 2000 surviving individuals (4). Without otters, sea urchins boomed and deforested kelp ecosystems during the 20th Century (5). Now we also know that this trophic cascade has climate-related implications in other parts of the marine ecosystem.

Underwater bites

Doug Rasher and collaborators have studied the phenomenon on the Aleutian Islands (6). The seabed of this archipelago is a mix of sandy beds, kelp forests, and calcareous reefs made up of calcium and magnesium carbonates fixed by the red algae Clathromorphum nereostratum. These reefs have grown at a rate of 3 cm annually for centuries as the fine film of living tissue covering the reef takes the carbonates from the seawater (7).

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Be wise about what you put online

21 03 2022

While you have little choice these days about posting your data and code online when you publish, here are some things to consider when contemplating putting potentially sensitive data online (modified excerpt from The Effective Scientist).


One aspect of making your data publicly available is the prickly issue of whether your data contain sensitive information.

Of course, there are many different types of ‘sensitive’ information that might accompany the more basic quantitative measurements of your datasets, with perhaps the most common being personal details of any human subjects. For example, if you are a medical researcher and your data are derived primarily from living human beings undergoing some procedure, trial, or intervention, then clearly you are bound by your human ethics approvals not to publish information like names, addresses, or anything that could be used to identify the subjects in your sample. In fact, human ethics approvals generally prohibit any sort of public accessibility to medical data that has personal information included; thus, the scientists concerned are being pulled in two different directions — keeping their subjects’ personal information out of the hands of the public, while still making the data available to other scientists.

There are ways around this, such as publishing only generic information online (i.e., by excluding personal identifiers) that could then be linked to the more sensitive data via unique identifiers. In these cases, any other researcher requiring the additional information would have to seek specific permission from the primary researchers, pending additional human-ethics approvals.

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Can we resurrect the thylacine? Maybe, but it won’t help the global extinction crisis

9 03 2022

NFSA

(published first on The Conversation)

Last week, researchers at the University of Melbourne announced that thylacines or Tasmanian tigers, the Australian marsupial predators extinct since the 1930s, could one day be ushered back to life.

The thylacine (Thylacinus cynocephalus), also known as the ‘Tasmanian tiger’ (it was neither Tasmanian, because it was once common in mainland Australia, nor was it related to the tiger), went extinct in Tasmania in the 1930s from persecution by farmers and habitat loss. Art by Eleanor (Nellie) Pease, University of Queensland.
Centre of Excellence for Australian Biodiversity and Heritage

The main reason for the optimism was the receipt of a A$5 million philanthropic donation to the research team behind the endeavour.

Advances in mapping the genome of the thylacine and its living relative the numbat have made the prospect of re-animating the species seem real. As an ecologist, I would personally relish the opportunity to see a living specimen.

The announcement led to some overhyped headlines about the imminent resurrection of the species. But the idea of “de-extinction” faces a variety of technical, ethical and ecological challenges. Critics (like myself) argue it diverts attention and resources from the urgent and achievable task of preventing still-living species from becoming extinct.

The rebirth of the bucardo

The idea of de-extinction goes back at least to the the creation of the San Diego Frozen Zoo in the early 1970s. This project aimed to freeze blood, DNA, tissue, cells, eggs and sperm from exotic and endangered species in the hope of one day recreating them.

The notion gained broad public attention with the first of the Jurassic Park films in 1993. The famous cloning of Dolly the sheep reported in 1996 created a sense that the necessary know-how wasn’t too far off.

The next technological leap came in 2008, with the cloning of a dead mouse that had been frozen at –20℃ for 16 years. If frozen individuals could be cloned, re-animation of a whole species seemed possible.

After this achievement, de-extinction began to look like a potential way to tackle the modern global extinction crisis.

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The sixth mass extinction is happening now, and it doesn’t look good for us

2 03 2022

Mounting evidence is pointing to the world having entered a sixth mass extinction. If the current rate of extinction continues we could lose most species by 2200. The implication for human health and wellbeing is dire, but not inevitable.

In the timeline of fossil evidence going right back to the first inkling of any life on Earth — over 3.5 billion years ago — almost 99 percent of all species that have ever existed are now extinct. That means that as species evolve over time — a process known as ‘speciation’ — they replace other species that go extinct.

Extinctions and speciations do not happen at uniform rates through time; instead, they tend to occur in large pulses interspersed by long periods of relative stability. These extinction pulses are what scientists refer to as mass extinction events.

The Cambrian explosion was a burst of speciation some 540 million years ago. Since then, at least five mass extinction events have been identified in the fossil record (and probably scores of smaller ones). Arguably the most infamous of these was when a giant asteroid smashed into Earth about 66 million years ago in what is now the Gulf of Mexico. The collision vapourised species immediately within the blast zone. Later, species were killed off by climate change arising from pulverised particulates suspended in the atmosphere, as well as intense volcano activity stimulated by the buckling of the Earth’s crust from the asteroid’s impact. Together, about 76 percent of all species around at the time went extinct, of which the disappearance of the dinosaurs is most well-known. But dinosaurs didn’t disappear altogether — the survivors just evolved into birds.

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Neo-colonialist attitudes ignoring poachernomics will ensure more extinctions

14 01 2022

No matter most people’s best intentions, poaching of species in Sub-Saharan Africa for horn and ivory continues unabated. Despite decades of policies, restrictions, interventions, protections, and incentives, many species of elephant and rhino are still hurtling toward extinction primarily because of poaching.

Clearly, we’re doing something heinously wrong.

Collectively, we have to take a long, hard look in the conservation mirror and ask ourselves some difficult questions. Why haven’t we been able to put any real dent in the illegal trade of poached elephant ivory and rhino horn? How many millions (billions?) of dollars have we spent seemingly to little avail? Why haven’t trade bans and intensive security measures done the trick?

The reasons are many, but they boil down to two main culprits:

  1. neo-colonialist sentiments driven by the best intentions of mainly overseas NGOs have inadvertently created the ideal conditions for the poaching economy — what we term poachernomics — to thrive by ensuring the continued restriction of legal supply of wildlife products; and
  2. shutting off conservation areas to local people and directing the bulk of ecotourism profits away from source communities have maintained steady poaching incentives in the absence of other non-destructive livelihoods.

In our new paper — Dismantling the poachernomics of the illegal wildlife trade (led by Enrico Di Minin of the Universities of Helsinki and KwaZulu-Natal, and co-authored by Michael ‘t Sas-Rolfes of the University of Oxford, Jeanetta Selier of the South African National Biodiversity Institute, Maxi Louis of the Namibian Association of Community-Based Natural Resources Management Support Organizations, and me) — published quietly in late 2021, we describe how poachernomics works, and why our efforts to incapacitate it have been so ineffectual.

First, what is poachernomics?

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Influential conservation papers of 2021

5 01 2022

Following my annual tradition, I present the retrospective list of the ‘top’ 20 influential papers of 2021 as assessed by experts in Faculty Opinions (formerly known as F1000). These are in no particular order. See previous years’ lists here: 2020, 201920182017201620152014, and 2013.


Amazonia as a carbon source linked to deforestation and climate change — “… confirms what the sparse forest inventory has suggested, that climate change and land-use change is driving Amazonian ecosystems toward carbon sinks. … the research team provides a robust estimate of the carbon dynamics of one of the world’s most important ecosystems and provides insights into the role of land use change and potentials for mitigating direct carbon losses in the future.

Organic and conservation agriculture promote ecosystem multifunctionality — “… a very clear insight into the trade-offs between the different ecosystem services and indicate that yield and product quality are lower in organic systems compared to conventional systems, yet organic systems have higher economic performance due to higher product prices and subsidies.

Biodiversity of coral reef cryptobiota shuffles but does not decline under the combined stressors of ocean warming and acidification — “… even with similar richness, community function is very likely to be perturbed by ocean warming/acidification with unpredictable impacts on economically important species such as fish and corals.

Local conditions magnify coral loss after marine heatwaves — “… show that climate-induced coral loss is greater in areas with elevated seaweed abundance and elevated sea urchin densities, both of which commonly result from local overfishing … effective local management can synergize with global efforts to mitigate climate change and help coral reefs survive the Anthropocene.

Large ecosystem-scale effects of restoration fail to mitigate impacts of land-use legacies in longleaf pine savannas — “… while restoration can have major benefits in longleaf savannas, land-use legacies have clear effects on many aspects of the ecosystem.

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Fancy a pangolin infected with coronavirus? Apparently, many people do

30 12 2021

The logic of money contradicts the logic of species conservation and human health. As illegal trade has driven pangolins to near extinction, their hunting and market value has kept increasing ― even when we have known that they act as coronavirus reservoirs in the middle of the Covid-19 pandemic.

Sunda pangolin (Manis javanica) in a monsoon forest (Sumba Island, Indonesia). With adult weights up to 10 kg and body lengths around half a metre, these animals are mostly solitary and nocturnal, feed on ants and termites, and love tree climbing using bark hollows to shelter and give birth to singletons. The species occurs across mainland and islands of South East Asia, and became ‘Endangered’ in 2008 and ‘Critically Endangered’ in 2014, following a 80% decline in the last 20 years due to hunting and poaching. It has been the most heavily trafficked Asian species, and the IUCN’s assessment states: “… the incentives for harvesting and illegally trading in the species are universally high based on the high financial value of pangolin parts and derivatives”. Captive breeding is unlikely to deter wild collection because (among other reasons) farming costs are high (more so on a large scale) and, even if the species could be traded legally, wild versus farmed pangolin products and individuals are difficult to distinguish (23). Photo courtesy of Michael Pitts

Urbanites are attracted to exotic species, materials, and places. Our purchasing power seems to give us the right to buy any ‘object’ that we can pay for, no matter how exotic the object might be. In such a capitalist rationale, it is no surprise that > 150 thousand illegal cargos with wild animals and plants have been confiscated in 149 countries over the last two decades, moving some 6000 species from one place of the planet to another (1).

Social networks show people interacting with all kinds of fauna, creating the illusion that any animal can become a pet (2). And there’s a multi-$billion market of wildlife for a diverse array of uses including collecting, food, ornamentation, leisure, clothing and medicine (3-5). The paradox is that the rarer a species is, the higher its market value runs and the more lucrative selling it turns out to be, leading to more exploitation and rocketing extinction risk (6).

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Remote areas not necessarily safe havens for biodiversity

16 12 2021

The intensity of threats to biodiversity from human endeavour becomes weaker as the distance to them increases.


As you move away from the big city to enjoy the countryside, you’ll notice the obvious increase in biodiversity. Even the data strongly support this otherwise subjective perception — there is a positive correlation between the degree we destroy habitat, harvest species, and pollute the environment, and the distance from big cities.

Remote locations are therefore usually considered safe havens and potential reservoirs for biodiversity. But our new study published recently in Nature Communications shows how this obvious pattern depicts only half of the story, and that global conservation management and actions might benefit from learning more about the missing part.

Communities are not just lists of individual species. Instead, they consist of complex networks of ecological interactions linking interdependent species. The structure of such networks is a fundamental determinant of biodiversity emergence and maintenance. However, it also plays an essential role in the processes of biodiversity loss. The decline or disappearance of some species might have detrimental —often fatal — effects on their associates. For example, a parasite cannot survive without its hosts, as much as a predator will starve without prey, or a plant will not reproduce without pollinators.

Events where a species disappears following the loss of other species on which it depends are known as co-extinctions, and they are now recognised as a primary driver of the ongoing global biodiversity crisis. The potential risk stemming from ecological dependencies is a major concern for all ecological systems.

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An eye on the past: a view to the future

29 11 2021

originally published in Brave Minds, Flinders University’s research-news publication (text by David Sly)

Clues to understanding human interactions with global ecosystems already exist. The challenge is to read them more accurately so we can design the best path forward for a world beset by species extinctions and the repercussions of global warming.


This is the puzzle being solved by Professor Corey Bradshaw, head of the Global Ecology Lab at Flinders University. By developing complex computer modelling and steering a vast international cohort of collaborators, he is developing research that can influence environmental policy — from reconstructing the past to revealing insights of the future.

As an ecologist, he aims both to reconstruct and project how ecosystems adapt, how they are maintained, and how they change. Human intervention is pivotal to this understanding, so Professor Bradshaw casts his gaze back to when humans first entered a landscape – and this has helped construct an entirely fresh view of how Aboriginal people first came to Australia, up to 75,000 years ago.

Two recent papers he co-authored — ‘Stochastic models support rapid peopling of Late Pleistocene Sahul‘, published in Nature Communications, and ‘Landscape rules predict optimal super-highways for the first peopling of Sahul‘ published in Nature Human Behaviour — showed where, how and when Indigenous Australians first settled in Sahul, which is the combined mega-continent that joined Australia with New Guinea in the Pleistocene era, when sea levels were lower than today.

Professor Bradshaw and colleagues identified and tested more than 125 billion possible pathways using rigorous computational analysis in the largest movement-simulation project ever attempted, with the pathways compared to the oldest known archaeological sites as a means of distinguishing the most likely routes.

The study revealed that the first Indigenous people not only survived but thrived in harsh environments, providing further evidence of the capacity and resilience of the ancestors of Indigenous people, and suggests large, well-organised groups were able to navigate tough terrain.

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