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What does ‘collapse’ mean, and should we continue using the term?

30 08 2022

The conservation, environment, and sustainability literature is rife with the term ‘collapse’, applied to concepts as diverse as species extinction to the complete breakdown of civilisation. I have also struggled with its various meanings and implications, so I’m going to attempt to provide some clarity on collapse for my own and hopefully some others’ benefit.

State transitions (Fig. 2 from Keith et al. (2015))

From a strictly ecological perspective, ‘collapse’ could be described in the following (paraphrased) ways:

abrupt transition of one ecosystem state to another, usually invoking the idea that something has declined in the process (species richness, beta diversity, functional diversity, trophic network connectance, trait volume, production, etc.);
extinction of infrastructure/key species that then precipitates co-extinction cascades;
variation in some ecosystem indicator beyond normal, long-term variation;
some ecosystem indicator that is forced ‘outside a safe operating space‘;
“a change from a baseline state beyond the point where an ecosystem has lost key defining features and functions, and is characterised by declining spatial extent, increased environmental degradation, decreases in, or loss of, key species, disruption of biotic processes, and ultimately loss of ecosystem services and functions“
in fisheries, a sustained period of low catches following a period of high catches;
“A theoretical threshold, beyond which an ecosystem no longer sustains most of its characteristic native biota or no longer sustains the abundance of biota that have a key role in ecosystem organization“

But there is still nor formal definition of ‘collapse’ in ecology, as identified by several researchers (Keith et al. 2013; Boitani et al. 2015; Keith et al. 2015; Sato and Lindenmayer 2017; Bland et al. 2018). While this oversight has been discussed extensively with respect to quantifying changes, I can find nothing in the literature that attempts a generalisable definition of what collapse should mean. Perhaps this is because it is not possible to identify a definition that is sufficiently generalisable, something that Boitani et al. (2015) described with this statement:

“The definition of collapse is so vague that in practice it will be possible (and often necessary) to define collapse separately for each ecosystem, using a variety of attributes and threshold values
Boitani et al. 2015

Despite all the work that has occurred since then, I fear we haven’t moved much beyond that conclusion.

Hell, cutting down the trees in the bush block next to my property constitutes a wholesale ‘collapse’ of the microcommunity of species using that patch of bush. An asteroid hitting the Earth and causing a mass extinction is also collapse. And everything in-between.

But at least ecologists have made some attempts to define and quantify collapse, even if an acceptable definition has not been forthcoming. The sustainability and broader environment literature has not even done that.

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Tags: apocalypse, collapse, ecological collapse, economic collapse, ecosystem collapse, environmental collapse, genocide, hysteresis, Planetary boundaries, societal collapse, state transition, tipping points
Categories : anthropocene, biodiversity, climate change, community ecology, conservation biology, decline, economics, ecosystem, ecosystem function, ecosystem services, Endarkenment, environmental policy, exploitation, extinction, famine, function, societies, sustainability

Losing half of tropical fish species as corals disappear

30 06 2021

When snorkelling in a reef, it’s natural to think of coral colonies as a colourful scenography where fish act in a play. But what would happen to the fish if the stage went suddenly empty, as in Peter Brook’s 1971 Midsummer Night’s Dream? Would the fish still be there acting their roles without a backdrop?

This question is not novel in coral-reef science. Ecologists have often compared reef fish diversity and biomass in selected localities before and after severe events of coral mortality. Even a temporary disappearance of corals might have substantial effects on fish communities, sometimes resulting in a local disappearance of more than half of local fish species.

Considering the multiple, complex ways fish interact with — and depend on — corals, this might appear as an obvious outcome. Still, such complexity of interactions makes it difficult to predict how the loss of corals might affect fish diversity in specific contexts, let alone at the global scale.

Focusing on species-specific fish-coral associations reveals an inconsistent picture with local-scale empirical observations. When looking at the fraction of local fish diversity that strictly depends on corals for food and other more generic habitat requirements (such as shelter and reproduction), the global picture suggests that most fish diversity in reef locality might persist in the absence of corals.

The mismatch between this result and the empirical evidence of a stronger coral dependence suggests the existence of many hidden ecological paths connecting fish to corals, and that those paths might entrap many fish species for which the association to corals is not apparent.

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Tags: climate change, coral reefs, corals, extinction, Global warming, reef fish
Categories : biodiversity, bottom-up ecology, climate change, conservation, coral reefs, decline, ecology, extinction, extinction debt, fish, function, habitat loss, marine, research, top-down ecology, trophic cascades

Time for a ‘cold shower’ about our ability to avoid a ghastly future

13 01 2021

“I wish it need not have happened in my time,” said Frodo. “So do I,’ said Gandalf, “and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us.”
Frodo Baggins and Gandalf, The Fellowship of the Ring

Today, 16 high-profile scientists and I published what I describe as a ‘cold shower’ about society’s capacity to avoid a ghastly future of warfare, disease, inequality, persecution, extinction, and suffering.

And it goes way beyond just the plight of biodiversity.

No one who knows me well would mistake me for an optimist, try as I might to use my colleagues’ and my research for good. Instead, I like to describe myself as a ‘realist’. However, this latest paper has made even my gloomier past outputs look downright hopeful.

And before being accused of sensationalism, let me make one thing abundantly clear — I sincerely hope that what we describe in this paper does not come to pass. Not even I am that masochistic.

I am also supportive of every attempt to make the world a better place, to sing about our successes, regroup effectively from our failures, and maintain hope in spite of evidence to the contrary.

But failing to acknowledge the magnitude and the gravity of the problems facing us is not just naïve, it is positively dangerous and potentially fatal.

It is this reason alone that prompted us to write our new paper “Underestimating the challenges of
avoiding a ghastly future” just published in the new journal, Frontiers in Conservation Science.

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Tags: carrying capacity, climate change, climate disruption, climate refugees, consumption, density feedback, extinction, governance, human population, over-consumption, political will, populism, sustainability
Categories : Africa, agriculture, alien species, anthropocene, biodiversity, biowealth, bushmeat, carbon, climate change, climate shift, conservation, coral reefs, decline, deforestation, development, disease, drought, economics, ecosystem, ecosystem function, ecosystem services, education, Endarkenment, environmental economics, environmental policy, environmental science, exploitation, extinction, extremism, fire, food, function, governance, habitat loss, harvest, health, human overpopulation, impact, invasive species, ocean, planning, pollination, poverty, propaganda, science, threatened species, toxification

Successful movers responding to climate change

16 06 2020

tropical fishes range shifts Ecologists often rely on measuring certain elements of a species’ characteristics, behaviour, or morphology to determine if these — what we call ‘traits’ — give them certain capacities to exploit their natural environments. While sometimes a bit arbitrarily defined, the traits that can be measured are many indeed, and sometimes they reveal rather interesting elements of a species’ resilience in the face of environmental change.

As we know, climate change is changing the way species are distributed around the planet, for the main (and highly simplified) reason that the environments in which they’ve evolved and to which they have adapted are changing.

In the simplest case, a warming climate means that there is a higher and higher chance you’ll experience temperatures that really don’t suit you that well (think of a koala or a flying fox baking in a tree when the thermometer reads +45° in the shade). Just like you seeking those nice, air-conditioned spaces on a scorcher of a day, species like to move to where conditions are more acceptable to their particular physiologies and behaviours.

When they can’t change fast enough, they go extinct.

Ecologists use life-history traits to predict which species have the highest probability of moving to new areas in response to climate change. Most studies into this phenomenon have largely ignored that range shifts in fact occur in sequential stages: (1) the species arrives in a new place for the first time, (2) its population increases in size (and extent), and (3) it can continue to persist in the new spot. Read the rest of this entry »

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Tags: Biogeography, climate change, Fish, marine fishes, native invasive species, range shifts, species' traits, traits, tropical fish
Categories : alien species, Australia, behaviour, bioclimatic envelope, biogeography, climate change, climate shift, coasts, community ecology, coral reefs, ecology, ecosystem, extinction, fish, food, function, invasive species, marine, monitoring, southern Australia, tropical

South Australia is still killing dingoes

14 04 2020

As we did for Victoria, here’s our submission to South Australia’s proposed changes to its ‘wild dog’ and dingo policy (organised again by the relentless and venerable Dr Kylie Cairns):

14 April 2020

The Honourable Tim Whetstone MP, Minister for Primary Industries and Regional Development, South Australia

cc: The Honourable David Speirs MP, Minister for Environment and Water, South Australia
cc: Primary Industries and Regions South Australia
cc: Dr Bradley Page, PIRSA Wild Dog Program

RE: PROPOSED CHANGES TO THE SA WILD DOG AND DINGO POLICY

Dear Minister,

The undersigned welcome the opportunity to comment on the proposed changes to the South Australian (SA) Government’s ‘Wild dog and Dingo’ declared animal policy under section 10 (1)(b) of the Natural Resources Management Act 2004. The proposed changes raise serious concerns for dingoes in SA because it:

1. Requires all landholders to follow minimum baiting standards, including organic producers or those not experiencing stock predation.

Requires dingoes within Ngarkat Conservation Park (Region 4) to be destroyed, with ground baiting to occur every 3 months.
Requires ground baiting on land irrespective of whether stock predation is occurring or not, or evidence of dingo (wild dog) presence.

2. Allows aerial baiting of dingoes (aka wild dogs) in all NRM regions – including within National Parks.

3. Uses inappropriate and misleading language to label dingoes as “wild dogs”

We strongly urge the PIRSA to reject the proposed amendments to the SA wild dog and dingo policy. Instead the PIRSA should seek consultation with scientific experts in ecology, biodiversity and wildlife-conflict to develop a policy which considers the important ecological and cultural identity of the dingo whilst seeking to minimise their impact on livestock using best-practice and evidence-based guidelines. Key to this aim, livestock producers should be assisted with the help of PIRSA to seek alternative stock protection methodology and avoid lethal control wherever possible. On the balance of scientific evidence, protection of dingoes should be enhanced rather than diminished. Widespread aerial baiting programs are not compatible with the continued persistence of genetically intact and distinct dingoes in SA.

In this context, we strongly emphasise the following points: Read the rest of this entry »

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Tags: 1080, control, dingo, environmental policy, poison, predator, shooting, South Australia, wild dog
Categories : Australia, biodiversity, cat, community ecology, conservation, dingo, ecosystem function, ecosystem services, environmental policy, ethics, exploitation, fox, function, genetics, harvest, human-wildlife conflict, invasive species, kangaroo, mammal, management, meso-predator release, predation, predator, recovery, science, South Australia, sustainability, threatened species, top-down ecology

A plant’s adaptive traits don’t follow climate conditions as you might expect

27 03 2020

mountain

Just a quick post today, my last one for March. Like probably most of you, I’ve been trying to pretend to be as normal as possible despite the COVID-19 surrealism all around me. But even COVID-19 has shifted my research to a small degree.

But I’m not going to talk about the global pandemic right now (I can almost hear the collective sigh of relief). Instead, I’m going to go back to topic and discuss a paper that I’ve just co-authored.

Last year I went to China’s Yunnan Province where I met some fantastic colleagues at the Xishuangbanna Tropical Botanical Garden who were doing some very cool stuff with the variation in plant functional traits across environmental gradients.

Well, those colleagues invited me to participate in one those research projects, and I’m happy to say that the result has just been published in Forests.

Measuring the functional traits of different alpine trees species in the Changbai Mountains of far north-eastern China (no, I didn’t get to go there), the research set out to test how these varied among species and elevation.

Of course, one expects that different trees use different combinations of traits to survive the rigours of mountain life (high variation in temperature, freezing, wind, etc.), but generally speaking, you might expect things like xylem vessel diameter and density to change more or less monotonically (i.e., changing in a consistent manner as elevation rises or falls). This is because trees should adapt their traits to the local conditions as best they can. Read the rest of this entry »

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Tags: Changbai Mountains, China, elevational gradient, functional traits, plant traits, plants, species distribution models, trees
Categories : bioclimatic envelope, biodiversity, biogeography, climate change, climate shift, conservation, conservation biology, ecology, function, research

Heat tolerance highly variable among populations and species

14 01 2020

Many ecological studies have examined the tolerance of terrestrial wildlife to high and low air temperatures over global scales (e.g., 1, 2, 3). This topic has been boosted in the last two decades by ongoing and predicted impacts of climate change on biodiversity (see summary of 2019 United Nation’s report here and here).

However, it is unfortunate that for most species, studies have measured thermal tolerance from a single location or population. Researchers interested in global patterns of thermal stress collect those measurements from the literature for hundreds to thousands of species [recently compiled in the GlobTherm database] (4), and are therefore often restricted to analysing one value of thermal tolerance per species.

Three of the 15 species of Iberian lacertids sampled in our study of thermal tolerance (9), including the populations of Algerian psammodromus (Psammodromus algirus), Geniez’s wall lizard (Podarcis virescens) and Western green lizard (Lacerta bilineata) sampled in Navacerrada (Madrid), Fuertescusa (Cuenca) and Moncayo (Soria), respectively. Photos by S. Herrando-Pérez

Using this approach, ecologists have concluded that cold tolerance is far more variable than heat tolerance across species from the tropics to the boreal zone (5-8). Consequently, tolerance to heat stress might be a species trait with limited potential to change in response to global warming compared to cold tolerance (5). Read the rest of this entry »

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Tags: biodiversity, climate change, climate change effects on biodiversity, climate disruption, ecology, ecophysiology, functional ecology, Global warming, heat tolerance, herpetology, lacertid, lizard, population variation, resilience, Spain, thermal tolerance
Categories : bioclimatic envelope, climate change, climate shift, function

Influential conservation ecology papers of 2019

24 12 2019

As I’ve done for the last six years, I am publishing a retrospective list of the ‘top’ 20 influential papers of 2019 as assessed by experts in F1000 Prime (in no particular order). See previous years’ lists here: 2018, 2017, 2016, 2015, 2014, and 2013.

Decline of the North American avifauna — … the first comprehensive assessment of population change in the North American avifauna.

Scientists’ warning to humanity: microorganisms and climate change — … [highlights] the crucial role of microbial transformations in determining set points for sea temperature, pH and ocean productivity … [identifies] microbial activity as the “life support system of the biosphere”.

(Note: Lots of people hated this one, basically because it appears to be severely flawed; nonetheless, it received several recommendations on F1000): The global tree restoration potential — … illustrates the substantial potential of capturing some of the excess carbon dioxide present in the earth’s atmosphere by planting trees.

Managing the middle: a shift in conservation priorities based on the global human modification gradient — … probably the best global assessment of spatial extent of human modification of natural terrestrial environments published to date.

Five decades of northern land carbon uptake revealed by the interhemispheric CO₂ gradient — … [concludes] that northern hemisphere [sic] vegetation and soil account for the majority of the terrestrial carbon sink, rather than tropical forests (not trying to display too many sour grapes here, but we’ve already reported this for the boreal forest, and they didn’t even bother to cite us — sad panda)

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Tags: agriculture, biodiversity, birds, carbon, carbon uptake, climate change, climate emergency, CO2, conservation, declines, drought, extinction, Fish, fisheries, forests, insects, marine ecology, microorganisms, pesticides, range edges, trees, urban biodiversity, wilderness
Categories : agriculture, anthropocene, biodiversity, biogeography, biowealth, birds, carbon, climate change, climate shift, community ecology, connectivity, conservation, conservation biology, conservation ecology, decline, deforestation, demography, ecology, economics, ecosystem, ecosystem function, ecosystem services, environmental policy, environmental science, exploitation, extinction, extinction debt, fish, fisheries, function, habitat loss, harvest, marine, planning, pollution, protected area

Environmental damage kills children

1 10 2019

Yes, childrenairpollution it’s a provocative title, I agree. But then again, it’s true.

But I don’t just mean in the most obvious ways. We already have good data showing that lack of access to clean water and sanitation kills children (especially in developing nations), that air pollution is a nasty killer of young children in particular, and now even climate change is starting to take its toll.

These aspects of child health aren’t very controversial, but when we talk about the larger suite of indicators of environmental ‘damage’, such as deforestation rates, species extinctions, and the overall reduction of ecosystem services, the empirical links to human health, and to children in particular, are far rarer.

This is why I’m proud to report the publication today of a paper on which I and team of wonderful collaborators (Sally Otto, Zia Mehrabi, Alicia Annamalay, Sam Heft-Neal, Zach Wagner, and Peter Le Souëf) have worked for several years.

I won’t lie — the path to publishing this paper was long and hard, I think mainly because it traversed so many different disciplines. But we persevered and today published the paper entitled ‘Testing the socioeconomic and environmental determinants of better child-health outcomes in Africa: a cross-sectional study among nations‘* in the journal BMJ Open.

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Tags: air pollution, breastfeeding, child health, children, corruption, diarrhoea, ecosystem services, environmental degradation, food supply, governance quality, health investment, human overpopulation, infectious disease, injury, Millennium Development Goals, over-population, paediatrics, pulmonary diseae, sanitation, stunting, Sustainable Development Goals, United Nations, water, wealth, World Health Organization
Categories : Africa, agriculture, anthropocene, biodiversity, biowealth, carbon, climate change, conservation, conservation biology, corruption, deforestation, demography, development, economics, ecosystem services, environmental Kuznets curve, environmental science, exploitation, extinction, food, function, governance, habitat loss, harvest, health, human overpopulation, investment, livestock, logging, modelling, pollution, poverty, Red List, societies, sustainability, threatened species, toxification, water

The Great Dying

30 09 2019

Here’s a presentation I gave earlier in the year for the Flinders University BRAVE Research and Innovation series:

There is No Plan(et) B — What you can do about Earth’s extinction emergency

Earth is currently experiencing a mass extinction brought about by, … well, … us. Species are being lost at a rate similar to when the dinosaurs disappeared. But this time, it’s not due to a massive asteroid hitting the Earth; species are being removed from the planet now because of human consumption of natural resources. Is a societal collapse imminent, and do we need to prepare for a post-collapse society rather than attempt to avoid one? Or, can we limit the severity and onset of a collapse by introducing a few changes such as removing political donations, becoming vegetarians, or by reducing the number of children one has?

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Tags: Anthropocene, climate change, climate emergency, collapse, extinction, extinction emergency, food supply, human-caused global warming, sustainability, The Great Dying
Categories : Australia, biodiversity, biowealth, carbon, climate change, conservation, conservation biology, corruption, decline, deforestation, development, drought, economics, ecosystem, ecosystem function, ecosystem services, education, environmental economics, environmental Kuznets curve, environmental policy, environmental science, exploitation, extinction, extinction debt, Flinders University, flood, food, fragmentation, function, governance, habitat loss, harvest, health, human overpopulation, impact, invasive species, livestock, logging, management, modelling, palaeo-ecology, pollination, pollution, poverty, recovery, reforestation, research, restoration, science, sustainability, synergies, threatened species, trophic cascades, video

Nothing like a good forest

31 07 2019

Our history and culture are intimately tied to the planet’s forests and the services they provide to all living beings. In modern times, forests also help combat the impacts of anthropogenic climate change, not only by acting as powerful sinks of the carbon excess resulting from our greenhouse-gas emissions, but also as thermal shields we and many other species can benefit from.

55_ForestBufferingPhotoPortadaQuercusCoverProposed2

Understory of the laurel forest in Garajonay National Park (La Gomera, Canary Islands) – also part of the World Network of Biosphere Reserves since 2012. The fog, combined with the cloud belt blowing from the Atlantic Ocean against the mountains (Garajonay is the highest peak at 1500 m), creates a mesic microclimate crucial for plant endemism. Forest canopies reinforce humidity and buffer temperature variation for many species. Photo: Paco Rodríguez.

If we were to choose a house to live, most would likely opt for one with water and electricity supply, noiseless nights, nearby leisure and shopping, and easy communication by public transport. Lacking only one of those aspects could be off-putting.

In truth, those who have the privilege of living in a stable household value it by the full set of available commodities. Similarly, the value of an ecosystem rests on its entire repertoire of ecological functions (1). And this is particularly so for forest ecosystems.

The ecological value of a forest relies on the collection of its native characteristics (2): how many autochthonous and mature trees it can host, how much photosynthesis it fuels, how many pollinisers it feeds, how much soil and water it creates and retains, and many more (3). Read the rest of this entry »

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Tags: climate change, climate emergency, ecosystem services, forests, habitat loss
Categories : anthropocene, biodiversity, biowealth, carbon, climate change, community ecology, conservation, deforestation, drought, ecology, ecosystem, ecosystem function, ecosystem services, endemism, extinction, fragmentation, function, habitat loss, prioritisation, protected area, recovery, reforestation, restoration, synergies

How to improve (South Australia’s) biodiversity prospects

9 04 2019

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 »

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Tags: biodiversity, ecological restoration, Environment Protection Authority, environmental legislation, EPA, invasive species, restoration, Rethinking Ecology, SOER, South Australia, State of the Environment
Categories : agriculture, Australia, biodiversity, biowealth, birds, carbon, climate change, connectivity, conservation, conservation biology, conservation ecology, decline, deforestation, development, drought, ecology, economics, ecosystem, ecosystem function, endemic, endemism, environmental policy, exploitation, extinction, extinction debt, Flinders University, fragmentation, function, governance, habitat loss, harvest, human-wildlife conflict, invasive species, investment, livestock, management, meso-predator release, monitoring, Murray-Darling, planning, pollination, predation, prioritisation, protected area, recovery, reforestation, research, reserve, restoration, South Australia, southern Australia, sustainability, threatened species, vegetation

Thirsty forests

1 02 2019

Climate change is one ingredient of a cocktail of factors driving the ongoing destruction of pristine forests on Earth. We here highlight the main physiological challenges trees must face to deal with increasing drought and heat.

Forests experiencing embolism after a hot drought. The upper-left pic shows Scots (*Pinus sylvestris*) and black (*P. nigra*) pines in *Montaña de Salvador* (Espuñola, Barcelona, Spain) during a hot Autumn in 2015 favouring a massive infestation by pine processionary caterpillars (*Thaumetopoea pityocampa*) and tree mortality the following year (Lluís Brotons/CSIC in InForest-CREAF-CTFC). To the right, an individual holm oak (*Quercus ilex*) bearing necrotic branches in Plasencia (Extremadura, Spain) during extreme climates from 2016 to 2017, impacting more than a third of the local oak forests (Alicia Forner/CSIC). The lower-left pic shows widespread die-off of trembling aspen (*Populus tremuloides*) from ‘Aspen Parkland’ (Saskatchewan, Canada) in 2004 following extreme climates in western North America from 2001 to 2002 (Mike Michaelian/Canadian Forest Service). To the right, several dead aspens near Mancos (Colorado, USA) where the same events hit forests up to one-century old (William Anderegg).

A common scene when we return from a long trip overseas is to find our indoor plants wilting if no one has watered them in our absence. But … what does a thirsty plant experience internally?

Like animals, plants have their own circulatory system and a kind of plant blood known as sap. Unlike the phloem (peripheral tissue underneath the bark of trunks and branches, and made up of arteries layered by live cells that transport sap laden with the products of photosynthesis, along with hormones and minerals — see videos here and here), the xylem is a network of conduits flanked by dead cells that transport water from the roots to the leaves through the core of the trunk of a tree (see animation here). They are like the pipes of a building within which small pressure differences make water move from a collective reservoir to every neighbours’ kitchen tap.

Water relations in tree physiology have been subject to a wealth of research in the last half a decade due to the ongoing die-off of trees in all continents in response to episodes of drought associated with temperature extremes, which are gradually becoming more frequent and lasting longer at a planetary scale (1).

Embolised trees

During a hot drought, trees must cope with a sequence of two major physiological challenges (2, 3, 4). More heat and less internal water increase sap tension within the xylem and force trees to close their stomata (5). Stomata are small holes scattered over the green parts of a plant through which gas and water exchanges take place. Closing stomata means that a tree is able to reduce water losses by transpiration by two to three orders of magnitude. However, this happens at the expense of halting photosynthesis, because the main photosynthetic substrate, carbon dioxide (CO₂), uses the same path as water vapour to enter and leave the tissues of a tree.

If drought and heat persist, sap tension reaches a threshold leading to cavitation or formation of air bubbles (6). Those bubbles block the conduits of the xylem such that a severe cavitation will ultimately cause overall hydraulic failure. Under those conditions, the sap does not flow, many parts of the tree dry out gradually, structural tissues loose turgor and functionality, and their cells end up dying. Thus, the aerial photographs showing a leafy blanket of forest canopies profusely coloured with greys and yellows are in fact capturing a Dantesque situation: trees in photosynthetic arrest suffering from embolism (the plant counterpart of a blood clot leading to brain, heart or pulmonary infarction), which affects the peripheral parts of the trees in the first place (forest dieback).

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Tags: climate change, climate disruption, dieback, ecophysiology, embolism, extinction, Global warming, phloem, photosynthesis, Quercus, xylem
Categories : anthropocene, biodiversity, climate change, climate shift, conservation, conservation biology, decline, deforestation, disease, drought, ecology, extinction, function, habitat loss, health, research

Influential conservation ecology papers of 2018

17 12 2018

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, 2016, 2015, 2014, and 2013.

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Tags: biodiversity hotspots, biodiversity loss, climate breakdown, climate change, cognition, coral reefs, disease, fieldwork, Fish, fisheries, fishing impacts, Great Barrier Reef, killer whales, mammals, nuisance species, plastics, predators, productivity, richness-productivity relationship, sharks, Species richness, wild areas
Categories : anthropocene, aquaculture, Australia, biodiversity, biowealth, carbon, climate change, climate shift, community ecology, connectivity, conservation, conservation biology, conservation ecology, coral reefs, decline, deforestation, demography, ecology, economics, ecosystem, ecosystem function, ecosystem services, environmental policy, environmental science, exploitation, extinction, extinction debt, fish, fisheries, food, fragmentation, function, habitat loss, harvest, human overpopulation, invasive species, management, marine, marine protected area, modelling, pollination, pollution

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.

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Tags: cold tolerance, ecophysiology, ectotherms, heat tolerance, Iberia, Lacertidae, lizards, macroecology, macrophysiology, reptiles
Categories : biodiversity, climate change, climate shift, conservation, conservation biology, conservation ecology, decline, ecology, environmental policy, extinction, function, habitat loss, management, research, science, threatened species

Biodiversity is everyone’s responsibility

13 07 2018

Workspace: Team Of Diverse Workers Put Hands Together I’m not sure if many South Australians are aware of this, but the Parliamentary Inquiry into Biodiversity by the Environment, Resources and Development Committee presented a report to the 53rd Parliament of South Australia in March 2017. I thought it worthwhile reproducing their executive summary here on CB.com (I’ve highlighted the text that I deem to be rather insightful and simultaneously damning from our own elected government representatives):

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This report summarises the findings and recommendations of the South Australian Parliament’s Environment, Resources and Development Committee’s inquiry into biodiversity in South Australia. Specifically, the inquiry investigated the regulatory and policy framework to determine whether it appropriately supports terrestrial and marine ecological processes, biodiversity values and abates species extinction.

The Committee found that in spite of the efforts of the State and Federal governments, industry and private landholders in South Australia, the condition of biodiversity in the State continues to decline. Species extinctions have occurred in the past and a further “extinction debt” still exists. There is no reason to believe that this trend will improve without a change to the way we approach biodiversity conservation.

A key theme to emerge from the Inquiry is that biodiversity conservation needs to be everyone’s responsibility; State and Federal government, industry, the broader community, and private landholders.

This also means that biodiversity conservation needs to occur across both public and private land, with actions coordinated at a landscape scale.

Making biodiversity conservation everyone’s responsibility requires a range of measures, including legislative reform, improved management of threats and greater involvement of the community. The provision of greater resources would yield faster results.

This report has focused on several key themes that emerged from submissions to the Inquiry.

Regulating for better biodiversity – South Australia’s legislative framework

South Australia’s current legislative framework does not provide for optimum biodiversity outcomes.

Three key issues contribute to this –

an out-of-date suite of environmental legislation that lacks cohesion and consistency, particularly regarding enforcement and compliance provisions;

inadequate and incomplete processes for identifying and protecting at-risk elements that need special measures (e.g. for protection of specific threatened species and ecological communities); and

inadequate consideration of biodiversity conservation in legislation that regulates human activities. In particular, there is a lack of cohesion between the environmental legislative and policy framework and land use planning, assessment and approval.

Statutory fragmentation of biodiversity considerations – that is, consideration of different aspects of biodiversity under different pieces of legislation – results in lack of cohesion and consistency, duplication and inefficiency, and makes it difficult to implement a landscape approach or to identify strategic opportunities and risks.

Taken as a whole, current enforcement provisions do not provide for effective and proportionate compliance action. Enforcement and compliance provisions across the relevant legislation are uneven in their approach. For example, penalties appear to be disproportionate and not risk-based (although there are some exceptions). Modern enforcement tools such as compliance orders, civil remedies and alternative penalties (such as administrative penalties, payment of damages including exemplary damages, remediation orders etc) are not included in all relevant legislation. There is some duplication in offences and inconsistency in the types of sanctions and penalty ranges.

There is an urgent need to amend the legislative framework to support any attempt to improve biodiversity outcomes.

The best approach will be based on clear, shared responsibility for biodiversity outcomes, supported by individual accountability. However, such a change will require policy development and drive.

To ensure forward momentum and improvements in the short term while developing the policy settings to support such a step-change, a staged approach could be implemented. There are various ways this could be achieved.

The Committee suggests a 3-stage approach to reforming the legislative framework. The Committee recommends the creation of a Biodiversity Expert Panel that is responsible for advancing this 3-stage approach.

The first stage will involve amendments to improve operation and effectiveness of the regulatory regime within current policy settings, acknowledging that as a result of Stage 3, provisions may be altered or moved into different pieces of legislation. Amendments generally would be to the existing ‘environmental’ Acts, and primarily to the National Parks and Wildlife Act 1972 and Native Vegetation Act 1991. They would include many of the specific areas for amendment identified in EDO submissions (2011 & 2015) as well as in the SA Government submission, for example, beginning with amendments to improve current environmental legislation.

Stage 2 would progress to amendments to improve integration between Acts and improve support for landholders and community participation.

Stage 3 would implement a system whereby all resource use and management would be managed by one piece of legislation, with protection of biodiversity and sustainable development at its core. Provisions for protected area management, and for the scientific work involved in identifying threatened species and communities, may be contained in separate legislation.

Threats, ecological resilience and restoration

The State’s native biodiversity is facing myriad of current threats, including habitat loss and fragmentation (due to development and changing land-use), pest plants and animals, and control burn regimes. There is a need for more stringent vegetation protection, better informed and enacted control and management strategies of known pest plants and animals, and a revision of burning regimes.

Future threats to the State’s biodiversity will be largely driven by climate change impacts and the interaction with existing major threats (e.g. urbanisation and changing land use). Adequately preparing for and managing such future threats will require knowledge of projected changes and pro-active preparation for such changes.

Working with the community

Involvement of the community is an essential part of any biodiversity conservation strategy for the State. It is a foundation stone for moving to a point where biodiversity conservation is everyone’s business.

Community engagement will become increasingly important for biodiversity conservation, especially given the growing role of volunteers to support works on public land as well as the voluntary conservation efforts of private landholders. The expanding role of volunteers reenforces that biodiversity conservation is everyone’s business.

South Australia’s approach to biodiversity conversation on private land needs to be reinvigorated.

Cross cutting themes

There were several cross cutting themes identified in submissions to the Inquiry. There was broad recognition of the strong cultural and historic significance of elements of biodiversity to Aboriginal people, and that this is often poorly understood outside those communities. Continuing to identify ways for Aboriginal people to contribute to land and water management in South Australia remains a priority.

With respect to knowledge generation, critical knowledge gaps exist that need to be filled and existing knowledge is not being adequately understood, communicated or applied. From a resourcing perspective, there is concern that insufficient funds are being allocated to biodiversity conservation, which is affecting work on public and private lands.

The management of over-abundant species in South Australia remains a challenge, noting the recent impacts of long-nose fur seals in the Lower Lakes and Coorong, and ongoing concerns regarding the impact of animals such as little corellas and some species of kangaroos on negative vegetation.

Comments : 5 Comments »
Tags: biodiversity, climate change, ecological resilience, environmental legislation, management, South Australia, State of the Environment
Categories : anthropocene, Australia, biodiversity, cat, climate change, climate shift, conservation, deforestation, development, ecosystem, environmental policy, extinction, extinction debt, fragmentation, function, habitat loss, invasive species, living dead, management, monitoring, Murray-Darling, planning, prioritisation, protected area, recovery, reserve, restoration, South Australia, southern Australia, sustainability, threatened species, water

What Works in Conservation 2018

23 05 2018

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 »

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Tags: conservation, conservation evidence, ecology, intervention, management, managers, policymakers, rehabilitation, restoration, University of Cambridge
Categories : amphibian, biodiversity, birds, captive breeding, climate change, conservation, conservation biology, conservation ecology, ecology, ecosystem, ecosystem function, ecosystem services, environmental policy, extinction, fish, fragmentation, function, governance, impact, invasive species, management, protected area, research, science, threatened species

Penguins cheated by ecosystem change

13 03 2018

Jorge Drexler sings “… I was committed not to see what I saw, but sometimes life is more complex than what it looks like …”*. This excerpt by the Oscar-winning Uruguayan singer seems to foretell the theme of this blog: how the ecological complexity of marine ecosystems can elicit false signals to their predators. Indeed, the fidelity of marine predators to certain feeding areas can turn demographically detrimental to themselves when the amount of available food shrinks. A study of jackass penguins illustrates the phenomenon in a context of overfishing and ocean warming.

Adult of jackass penguin (Spheniscus demersus) from Robben Island (South Africa) — in the inset, one of the first juveniles released with a satellite transmitter on its back. The species is ‘Endangered’ under IUCN’s criteria (28), following a recent halving of the total population currently estimated at ~ 80,000 adults. Jackass penguins are the only penguins living in Africa, and owe their common name to their vocalisations (you can hear their braying sounds here); adults are ~ 50 cm tall and weigh ~ 3 kg. Photos courtesy of Richard Sherley.

Surface temperature, dissolved oxygen, acidity and primary productivity are, by and large, the top four environmental factors driving the functionality of marine ecosystems (1). Growing scientific evidence supports the idea that anthropogenic warming of the atmosphere and the oceans correlates with this quartet (2). For instance, marine primary productivity is enhanced by increased temperatures (3), but a warmer sea surface intensifies stratification, i.e., stacked layers of seawater with contrasting physical and chemical properties.

In coastal areas experiencing ‘upwelling’ (where winds displace surface water, allowing deep water laden with nutrients to reach the euphotic zone where plankton communities feast), stratification weakens upwelling currents and, in turn, limits the growth of plankton (4) that fuels the entire trophic web, including our fisheries. The study of these complex trophic cascades is particularly cumbersome from the perspective of large marine predators because of their capacity to move long distances, from hundreds to thousands of kilometres (5), with strong implications for their conservation (6).

With those caveats in mind, Richard Sherley and colleagues satellite-tracked the movement of 54 post-fledged, juvenile jackass penguins (Spheniscus demersus) for 2-3 years (7). All individuals had been hatched in eight colonies (accounting for 80% of the global population), and were equipped with platform terminal transmitters. Jackass penguins currently nest in 28 island and mainland locations between South Africa and Namibia. Juveniles swim up to 2000 km in search of food and, when approaching adulthood, return to their native colonies where they reproduce and reside for the remainder of their lives (watch individuals swimming here).

The natural history of this species is linked to the Southern Hemisphere’s trade winds (‘alisios’ for Spanish speakers), which blow from the southeast to the tropics. In the South Atlantic, trade winds sustain the Benguela Current, the waters of which surface from some 300 m of depth and fertilise the marine ecosystems stretching from the Western coasts of South Africa to Angola (8). Read the rest of this entry »

Comments : 1 Comment »
Tags: anchovy, Benguela, climate change, fisheries, food web, Global warming, jellies, jellyfication, Namibia, Overfishing, penguin, penguins, pilchard, South Africa, upwelling
Categories : Africa, behaviour, birds, climate change, climate shift, coasts, decline, ecology, ecosystem, ecosystem function, fish, fisheries, food, function, harvest, impact, research, science, trophic cascades

Influential conservation ecology papers of 2017

27 12 2017

As I have done for the last four years (2016, 2015, 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 »

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Tags: Africa, Amazon, biodiversity, boundaries, cats, climate change, decline, depression, disturbance, dogs, drowning, elevation, eutrophication, Fish, forests, fragmentation, Genetics, Global warming, green spaces, insects, mental health, networks, nutrient cycling, ocean, oil, oil spill, oxygen, photosynthesis, phytoplankton, Planetary boundaries, Predation, predators, prey, productivity, rainfall, richness, Soil, wildebeest, zooplankton
Categories : Africa, algae, Amazon, anthropocene, biodiversity, biowealth, cat, climate change, community ecology, connectivity, conservation, conservation ecology, coral reefs, decline, deforestation, drought, ecology, ecosystem, ecosystem function, ecosystem services, environmental science, eutrophication, extinction, extinction debt, fish, fragmentation, function, genetics, habitat loss, marine, pollination, toxicology

Tiny, symbiotic organisms protect corals from predation and disease

20 12 2017

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 »