Extinction cascades

3 06 2020

A recent online interview I did on the role of extinction cascades in mass extinctions:





Influential conservation ecology papers of 2019

24 12 2019

Bradshaw-Waves breaking on rocks Macquarie Island
As I’ve done for the last six years, I am publishing a retrospective list of the ‘top’ 20 influential papers of 2109 as assessed by experts in F1000 Prime (in no particular order). See previous years’ lists here: 20182017, 20162015, 2014, and 2013.

 

 

 

 

 

 

Read the rest of this entry »





Koala extinctions past, present, and future

12 06 2019
Koala

Photo by John Llewelyn

Koalas are one of the most recognised symbols of Australian wildlife. But the tree-living marsupial koala is not doing well throughout much of its range in eastern Australia. Ranging as far north as Cairns in Queensland, to as far west as Kangaroo Island in South Australia, the koala’s biggest threats today are undeniably deforestation, road kill, dog attacks, disease, and climate change.

With increasing drought, heatwaves, and fire intensity and frequency arising from the climate emergency, it is likely that koala populations and habitats will continue to decline throughout most of their current range.

But what was the distribution of koalas before humans arrived in Australia? Were they always a zoological feature of only the eastern regions?

The answer is a resounding ‘no’ — the fossil record reveal a much more complicated story.

Read the rest of this entry »





How to improve (South Australia’s) biodiversity prospects

9 04 2019
Fig2

Figure 2 (from the article). Overlaying the South Australia’s Protected Areas boundary data with the Interim Biogeographic Regionalisation for Australia layer indicates that 73.2% of the total protected area (excluding Indigenous Protected Areas) in South Australia lies in the arid biogeographic regions of Great Victoria Desert (21.1%), Channel Country (15.2%), Simpson Strzelecki Dunefields (14.0%), Nullarbor (9.8%), Stony Plains (6.6%), Gawler (6.0%), and Hampton (0.5%). The total biogeographic-region area covered by the remaining Conservation Reserves amounts to 26.2%. Background blue shading indicates relative average annual rainfall.

If you read CB.com regularly, you’ll know that late last year I blogged about the South Australia 2108 State of the Environment Report for which I was commissioned to write an ‘overview‘ of the State’s terrestrial biodiversity.

At the time I whinged that not many people seemed to take notice (something I should be used to by now in the age of extremism and not giving a tinker’s about the future health of the planet — but I digress), but it seems that quietly, quietly, at least people with some policy influence here are starting to listen.

Not satisfied with merely having my report sit on the virtual shelves at the SA Environment Protection Authority, I decided that I should probably flesh out the report and turn it into a full, peer-reviewed article.

Well, I’ve just done that, with the article now published online in Rethinking Ecology as a Perspective paper.

The paper is chock-a-block with all the same sorts of points I covered last year, but there’s a lot more, and it’s also a lot better referenced and logically sequenced.

Read the rest of this entry »





How to fix a broken river

5 04 2019

murraycod

It seems that most of what I do these days is measure, model, or otherwise quantify environmental damage. While I dabble in restoration, occasionally I’m involved in a project that really can make a positive difference.

If you’re an Australian, you’ll know a thing or two about just how much of a clusterfuck our biggest river system has turned into. From mismanagement, to outright theft, to lobbyist-driven over-exploitation, to climate change itself, the Murray-Darling system is now in a right mess.

So, I’ll pretext this post with a caveat — no amount of ecological restoration can ‘fix’ a compromised river if there’s no water in it. Goes without saying, really.

But, if you do have water, then there are things one can do to promote populations of various creatures living in it, like fish.

Dubbed the ‘honeypot effect’ — we have just shown that providing woody habitat, or ‘snags’, for native fish in the Murray River increases population size. Read the rest of this entry »





The dingo is a true-blue, native Australian species

7 03 2019

dingo(reproduced from The Conversation)

Of all Australia’s wildlife, one stands out as having an identity crisis: the dingo. But our recent article in the journal Zootaxa argues that dingoes should be regarded as a bona fidespecies on multiple fronts.

This isn’t just an issue of semantics. How someone refers to dingoes may reflect their values and interests, as much as the science.

How scientists refer to dingoes in print reflects their background and place of employment, and the Western Australian government recently made a controversial attempt to classify the dingo as “non-native fauna”.

How we define species – called taxonomy – affects our attitudes, and long-term goals for their conservation.

What is a dog?

Over many years, dingoes have been called many scientific names: Canis lupus dingo (a subspecies of the wolf), Canis familiaris (a domestic dog), and Canis dingo (its own species within the genus Canis). But these names have been applied inconsistently in both academic literature and government policy.

This inconsistency partially reflects the global arguments regarding the naming of canids. For those who adhere to the traditional “biological” species concept (in which a “species” is a group of organisms that can interbreed), one might consider the dingo (and all other canids that can interbreed, like wolves, coyotes, and black-backed jackals) to be part of a single, highly variable and widely distributed species.

Members of the Canis genus: wolf (Canis lupus), coyote (Canis latrans), Ethiopian wolf (Canis simensis), black-backed jackal (Canis mesomelas), dingo (Canis dingo), and a representative of the domestic dog (Canis familiaris).

Read the rest of this entry »





Influential conservation ecology papers of 2018

17 12 2018

e35f9ddeada029a053a15cd023abadf5
For the last five years I’ve published a retrospective list of the ‘top’ 20 influential papers of the year as assessed by experts in F1000 Prime — so, I’m doing so again for 2018 (interesting side note: six of the twenty papers highlighted here for 2018 appear in Science magazine). See previous years’ posts here: 2017, 20162015, 2014, and 2013.

Read the rest of this entry »





Global warming causes the worst kind of extinction domino effect

25 11 2018

Dominos_Rough1-500x303Just under two weeks ago, Giovanni Strona and I published a paper in Scientific Reports on measuring the co-extinction effect from climate change. What we found even made me — an acknowledged pessimist — stumble in shock and incredulity.

But a bit of back story is necessary before I launch into describing what we discovered.

Last year, some Oxbridge astrophysicists (David Sloan and colleagues) published a rather sensational paper in Scientific Reports claiming that life on Earth would likely survive in the face of cataclysmic astrophysical events, such as asteroid impacts, supernovae, or gamma-ray bursts. This rather extraordinary conclusion was based primarily on the remarkable physiological adaptations and tolerances to extreme conditions displayed by tardigrades— those gloriously cute, but tiny (most are around 0.5 mm long as adults) ‘water bears’ or ‘moss piglets’ — could you get any cuter names?

aHR0cDovL3d3dy5saXZlc2NpZW5jZS5jb20vaW1hZ2VzL2kvMDAwLzA5OC81NzMvb3JpZ2luYWwvc3dpbW1pbmctdGFyZGlncmFkZS5qcGc=

Found almost everywhere and always (the first fossils of them date back to the early Cambrian over half a billion years ago), these wonderful little creatures are some of the toughest metazoans (multicellular animals) on the planet. Only a few types of extremophile bacteria are tougher.

So, boil, fry or freeze the Earth, and you’ll still have tardigrades around, concluded Sloan and colleagues.

When Giovanni first read this, and then passed the paper along to me for comment, our knee-jerk reaction as ecologists was a resounding ‘bullshit!’. Even neophyte ecologists know intuitively that because species are all interconnected in vast networks linked by trophic (who eats whom), competitive, and other ecological functions (known collectively as ‘multiplex networks’), they cannot be singled out using mere thermal tolerances to predict the probability of annihilation. Read the rest of this entry »





Ecophysiological feedbacks under climate change

29 10 2018

Variability in heat tolerance among populations modifies the climate-driven periods of diurnal activity expected for ectotherm species. We illustrate this phenomenon for Iberian lizards in a paper we have just published in the Journal of Animal Ecology (blog post reproduced with permission by the Journal; see related blog).

Common wall lizard (Podarcis muralis, male) and three localities where the species is abundant in Spain, left to right including Valdesquí/Madrid (Central System), Peñagolosa/Castellón (Iberian System) and El Portalet/Huesca (The Pyrenees).

Iberia is a wonderful natural laboratory, with a complex blend of flat/hilly, open/woody and coastal/continental terrain, swept by climatic gradients of temperature and moisture. In 2013, I launched a BES-supported project about the thermal ecology of Iberian lizards and managed to drive over much of the Iberian Peninsula in fairly little time. Not being a reptile specialist myself, I was confronted by the consistent observation that lizard populations occupied very different habitats across the known distribution of each of the ~ 25 known Iberian species belonging to the family Lacertidae.

For instance, the common wall lizard (Podarcis muralis) likes water, rocks and mountains, but you can find this pencil-long reptile at the top of a summit, along the slopes or riversides of shallow and deep ravines, on little stones barely surfacing above peatland grasslands, or among the bricks of buildings. These animals must experience different local climates conditional on where they live, and adapt their thermal physiology accordingly.

Having then started a postdoc in Miguel Araújo’s lab — a world-class site for global change ecology and ‘big’ biodiversity patterns — I reviewed a sizeable body of literature looking into large-scale gradients of thermal tolerance. Most of those papers had collated (mostly) one estimate of tolerance from each of tens to thousands of species, then mapped them against regional and global metrics of climate change through sophisticated mathematical frameworks. But these studies rarely accounted for population-level thermal tolerance.

Read the rest of this entry »




How to feed the world without costing the Earth

5 07 2018

image_normalI’m excited to announce the upcoming public lecture by world-renowned sustainability scientist, Professor Andrew Balmford, at Flinders University on 17 July 2018.

Andrew is Professor of Conservation Science and a Royal Society Wolfson Research Merit Award holder at the Department of Zoology, University of Cambridge, and is on sabbatical at University of Tasmania until December 2018. His main research interests are exploring how conservation might best be reconciled with land-demanding activities such as farming, quantifying the costs and benefits of effective conservation, and examining what works in conservation. In his book Wild Hope (Chicago University Press), he argues that cautious optimism is essential in tackling environmental challenges. Andrew helped establish the Student Conference on Conservation Science, and Earth Optimism.

EcolEvolFlindersLogoProfessor Balmford will be presenting his seminar “How to feed the world without costing the Earth” (hosted by the Ecology & Evolution Research Group) at the Bedford Park Campus of Flinders University in South Lecture Theatre 1, from 12:00-13:00 on 17 July 2018. All are welcome.

Abstract: Globally, agriculture is the greatest threat to biodiversity and a major contributor to anthropogenic greenhouse gas emissions. How we choose to deal with rising human food demand will to a large degree determine the state of biodiversity and the wider environment in the 21st century. Read the rest of this entry »





What Works in Conservation 2018

23 05 2018

P1230308

Do you have a copy of this book? If not, why not?

 

This book is free to download. This book contains the evidence for the effectiveness of over 1200 things you might do for conservation. If you don’t have a copy, go and download yourself a free one here, right now, before you even finish reading this article. Seriously. Go. You’ll laugh, you’ll cry, it’ll change your life.

Why you’ll laugh

OK, I may have exaggerated the laughing part. ‘What Works in Conservation 2018’ is a serious and weighty tome, 660 pages of the evidence for 1277 conservation interventions (anything you might do to conserve a species or habitat), assessed by experts and graded into colour-coded categories of effectiveness. This is pretty nerdy stuff, and probably not something you’ll lay down with on the beach or dip into as you enjoy a large glass of scotch (although I don’t know your life, maybe it is).

But that’s not really what it’s meant for. This is intended as a reference book for conservation managers and policymakers, a way to scan through your possible solutions and get a feel for those that are most likely to be effective. Once you have a few ideas in mind, you can follow the links to see the full evidence base for each study at conservationevidence.com, where over 5000 studies have been summarised into digestible paragraphs.

The book takes the form of discrete chapters on taxa, habitats or topics (such as ‘control of freshwater invasives’). Each chapter is split into IUCN threat categories such as ‘Agriculture’ or ‘Energy production and mining’. For each threat there are a series of interventions that could be used to tackle it, and for each of these interventions the evidence has been collated. Experts have then graded the body of the evidence over three rounds of Delphi scoring, looking at the effectiveness, certainty in the evidence (i.e., the quality and quantity of evidence available), and any harms to the target taxa. These scores combine to place each intervention in a category from ‘Beneficial’ to ‘Likely to be ineffective or harmful’. Read the rest of this entry »





A life of fragmentation

9 05 2018

LauranceWhat do you say to a man whose list of conservation awards reads like a Star Wars film intro, who has introduced terms like the ‘hyperdynamism hypothesis’ to the field of ecology, and whose organisation reaches over one million people each week with updates of the scientific kind?

Interview with Bill Laurance by Joel Howland (originally published in Conjour)


Well, I started by asking what it is that leads him to love the natural world to the extent he does. His answer was disarmingly simple.

“I grew up in the country, on an Oregon cattle ranch, and I think my love of nature just evolved naturally from that. When I was a young kid my dad and I did some fishing and ‘rock-hounding’— searching for rare stones and fossils. As an adolescent and teen I loved heading off into a forest or wilderness, rifle in hand – back in those days you could do that – to see whatever I could find. I watched red foxes hunting, eagles mating, and even heard a mountain lion scream. I got to be a pretty good duck and game-bird hunter.”

He’s quick to point out, however, he realised his taste for guns was not so developed as his love of nature.

“I gave up my rifles for a camera, and enjoyed that even more. I really got into photography for a while. Nature has always just calmed and fascinated me —I guess that’s partly why I became a conservationist.”

Who is Bill Laurance?

William F. Laurance is one of the leading ecology and conservation scientists globally, publishing dozens of papers in journals like Nature and Science, and rewriting the way scientists in the field research the complex interactions between flora and fauna — particularly in rainforests like the Amazon.

He is a Distinguished Research Professor at James Cook University in Australia, a Fellow of the Australian Academy of Science and the American Association for the Advancement of Science, and has received an Australian Laureate Fellowship from the Australian Research Council.

All this for a man from western USA who dreamed of running a zoo. Instead, he has travelled a path of intricate and game-changing research, trailblazing awareness campaigns and inspirational writings that have driven the way many see the environment over the past few decades.

Despite this profile, Laurance gave some time to tell Conjour about his life, his passion and his aims. I asked him what — considering his impressive CV — the future holds.

His response seems a real insight to the man. Read the rest of this entry »





Influential conservation ecology papers of 2017

27 12 2017

Gannet Shallow Diving 03
As I have done for the last four years (20162015, 2014, 2013), here’s another retrospective list of the top 20 influential conservation papers of 2017 as assessed by experts in F1000 Prime.

Read the rest of this entry »





Tiny, symbiotic organisms protect corals from predation and disease

20 12 2017

hydrozoan polyp

Hydrozoan polyps living on the surface of a coral (photo credit: S. Montano)

Corals could have some unexpected allies to cope with the multi-faceted threats posed by climate change.

In a new study published today in Proceedings of the Royal Society B, Montano and colleagues show how tiny hydrozoans smaller than 1 mm and commonly found in dense colonies on the surface of hard corals (see above photo) play an important ecological role.

Visually examining ~ 2500 coral colonies in both Maldivian and Saudi Arabian reefs, the scientists searched for signs of predation, temperature-induced stress, and disease. For each colony, they also recorded the presence of symbiotic hydrozoans. They demonstrated that corals living in association with hydrozoans are much less prone to be eaten by corallivorous (i.e., ‘coral-eating’) fish and gastropods than hydrozoan-free corals.

A likely explanation for this pattern could be the deterring action of hydrozoan nematocysts (cells capable of ejecting a venomous organelle, which are the same kinds found in jellyfish tentacles). An individual hydrozoan polyp of less than 1 mm clearly cannot cope with a corallivorous fish that is a billions of times larger, yet hydrozoans can grow at high densities on the surface of corals (sometimes > 50 individuals per cm2). This creates a sort of a continuous, ‘urticating‘ carpet that can discourage fish from foraging. Read the rest of this entry »





You know you’re screwed when the insects disappear

31 10 2017

dead cicadaLast Friday, ABC 891 here in Adelaide asked me to comment on a conservation paper doing the news rounds last week. While it has been covered extensively in the media (e.g., The Guardian, CNN, and Science), I think it’s probably going to be one of those things that people unfortunately start to forget right away. But this is decidedly something that no one should be forgetting.

While you can listen to me chat about this with the lovely Sonya Feldhoff on the ABC (I start chin-wagging around the 14:30 mark), I thought it prudent to remind CB.com readers just how devastatingly important this study is.

While anyone with a modicum of conservation science under her belt will know that the Earth’s biodiversity is not doing well, the true extent of the ecological tragedy unfolding before our very eyes really came home to us back in 2014 with the publication of WWF’s Living Planet Report. According to a meta-analysis of 10,380 population trends from over 3000 species of birds, reptiles, amphibians, mammals, and fish, the report concluded that the Earth has lost over 50% of the individuals in vertebrate populations since 1970. Subsequent revisions (and more population trends from more species) place the decline at over 60% by 2020 (that’s only a little over two years away). You can also listen to me speak about this on another radio show.

If that little bit of pleasant news didn’t make the pit of your stomach gurgle and a cold sweat break out on the back of your neck, you’re probably not human. But hang on, boys and girls — it gets so much worse! The publication in PLoS One on 18 October about Germany’s insect declines might be enough to tip you over the edge and into the crevasse of mental instabilityRead the rest of this entry »





Four decades of fragmentation

27 09 2017

fragmented

I’ve recently read perhaps the most comprehensive treatise of forest fragmentation research ever compiled, and I personally view this rather readable and succinct review by Bill Laurance and colleagues as something every ecology and conservation student should read.

The ‘Biological Dynamics of Forest Fragments Project‘ (BDFFP) is unquestionably one of the most important landscape-scale experiments ever conceived and implemented, now having run 38 years since its inception in 1979. Indeed, it was way ahead of its time.

Experimental studies in ecology are comparatively rare, namely because it is difficult, expensive, and challenging in the extreme to manipulate entire ecosystems to test specific hypotheses relating to the response of biodiversity to environmental change. Thus, we ecologists tend to rely more on mensurative designs that use existing variation in the landscape (or over time) to infer mechanisms of community change. Of course, such experiments have to be large to be meaningful, which is one reason why the 1000 km2 BDFFP has been so successful as the gold standard for determining the effects of forest fragmentation on biodiversity.

And successful it has been. A quick search for ‘BDFFP’ in the Web of Knowledge database identifies > 40 peer-reviewed articles and a slew of books and book chapters arising from the project, some of which are highly cited classics in conservation ecology (e.g., doi:10.1046/j.1523-1739.2002.01025.x cited > 900 times; doi:10.1073/pnas.2336195100 cited > 200 times; doi:10.1016/j.biocon.2010.09.021 cited > 400 times; and doi:10.1111/j.1461-0248.2009.01294.x cited nearly 600 times). In fact, if we are to claim any ecological ‘laws’ at all, our understanding of fragmentation on biodiversity could be labelled as one of the few, thanks principally to the BDFFP. Read the rest of this entry »





Seeing the wood for the trees

11 07 2016

The Forest Synopsis: Photo of the Anamalai Tiger Reserve, India, by Claire Wordley

The Forest Synopsis: Photo of the Anamalai Tiger Reserve, India, by Claire Wordley

From the towering kapoks of South America to the sprawling banyans of South Asia, from misty cloud forests to ice-covered pines, forests are some of the most diverse and important ecosystems on Earth. However, as conservationists and foresters try to manage, conserve and restore forests across the world, they often rely on scanty and scattered information to inform their decisions, or indeed, no information at all. This could all change.

This week sees the launch of the Forest Synopsis from Conservation Evidence, a free resource collating global scientific evidence on a wide range of conservation-related actions. These aim to include all interventions that conservationists and foresters are likely to use, such as changing fire regimes, legally protecting forests or encouraging seed-dispersing birds into degraded forests.

Making conservation work

“We hear a lot about how important it is to do evidence-based conservation”, says Professor Bill Sutherland at the University of Cambridge, UK, “but in reality getting a handle on what works is not easy. That’s why we set up Conservation Evidence, to break down the barriers between conservationists and the scientific evidence that they need to do their jobs.” Read the rest of this entry »





Sensitive numbers

22 03 2016

toondoo.com

A sensitive parameter

You couldn’t really do ecology if you didn’t know how to construct even the most basic mathematical model — even a simple regression is a model (the non-random relationship of some variable to another). The good thing about even these simple models is that it is fairly straightforward to interpret the ‘strength’ of the relationship, in other words, how much variation in one thing can be explained by variation in another. Provided the relationship is real (not random), and provided there is at least some indirect causation implied (i.e., it is not just a spurious coincidence), then there are many simple statistics that quantify this strength — in the case of our simple regression, the coefficient of determination (R2) statistic is a usually a good approximation of this.

In the case of more complex multivariate correlation models, then sometimes the coefficient of determination is insufficient, in which case you might need to rely on statistics such as the proportion of deviance explained, or the marginal and/or conditional variance explained.

When you go beyond this correlative model approach and start constructing more mechanistic models that emulate ecological phenomena from the bottom-up, things get a little more complicated when it comes to quantifying the strength of relationships. Perhaps the most well-known category of such mechanistic models is the humble population viability analysis, abbreviated to PVA§.

Let’s take the simple case of a four-parameter population model we could use to project population size over the next 10 years for an endangered species that we’re introducing to a new habitat. We’ll assume that we have the following information: the size of the founding (introduced) population (n), the juvenile survival rate (Sj, proportion juveniles surviving from birth to the first year), the adult survival rate (Sa, the annual rate of surviving adults to year 1 to maximum longevity), and the fertility rate of mature females (m, number of offspring born per female per reproductive cycle). Each one of these parameters has an associated uncertainty (ε) that combines both measurement error and environmental variation.

If we just took the mean value of each of these three demographic rates (survivals and fertility) and project a founding population of = 10 individuals for 1o years into the future, we would have a single, deterministic estimate of the average outcome of introducing 10 individuals. As we already know, however, the variability, or stochasticity, is more important than the average outcome, because uncertainty in the parameter values (ε) will mean that a non-negligible number of model iterations will result in the extinction of the introduced population. This is something that most conservationists will obviously want to minimise.

So each time we run an iteration of the model, and generally for each breeding interval (most often 1 year at a time), we choose (based on some random-sampling regime) a different value for each parameter. This will give us a distribution of outcomes after the 10-year projection. Let’s say we did 1000 iterations like this; taking the number of times that the population went extinct over these iterations would provide us with an estimate of the population’s extinction probability over that interval. Of course, we would probably also vary the size of the founding population (say, between 10 and 100), to see at what point the extinction probability became acceptably low for managers (i.e., as close to zero as possible), but not unacceptably high that it would be too laborious or expensive to introduce that many individuals. Read the rest of this entry »





To spare or to share, that is a muddled question

9 10 2015

Unfortunately, it ain't this simple (from doi:10.1016/j.foodpol.2010.11.008)

Unfortunately, it ain’t this simple (from doi:10.1016/j.foodpol.2010.11.008)

Certain research trends in any field are inevitable, because once a seductive can of research-question worms is opened, it’s difficult to resist the temptation to start hooking in. Of course, I’m not against popular trends in research per se if they lead to a productive, empirical evaluation of the complexities involved, but it can sometimes result in a lot of wasted time. For example, in conservation ecology we’ve had to suffer 15 years of wasted effort on disproving neutral theory, we’ve bashed heads unnecessarily regarding the infamous SLOSS (‘Single Large Or Several Small’ reserves) debates of the 1970s and 1980s, and we’ve pilfered precious years arguing about whether density feedback actually exists (answer: it does).

The latest populist research trend in conservation seems to be the ‘land sparing versus land sharing’ debate, which, I (and others) argue, is largely an overly simplistic waste of time, money and intellectual advancement to the detriment of both biodiversity and human well-being.

Land sparing is generally used in reference to agricultural practices (although in theory, it could apply to any human endeavour where native vegetation cover is required to be removed or degraded, such as for electricity production) that are purposely made to be high-yielding so that they require the smallest amount of land. At the other extreme (and the ‘two extremes’ of a continuum concept is half the bloody problem here), land sharing requires a larger land footprint because it relies on lower-yielding, biodiversity-friendly (agricultural) practices. Proponents of land sparing argue that only by amalgamating patches of remnant native vegetation can we avoid massive fragmentation and the pursuant loss of biodiversity, whereas those pushing for land sparing argue that the matrix between the big undeveloped bits must be exploited in a more biodiversity-friendly way to allow species to persist.

As it turns out, they’re both right (but their single-minded, extremist positions are not). Read the rest of this entry »