Greater death rates for invasive rabbits from interacting diseases

30 05 2018

When it comes to death rates for invasive European rabbits (Oryctolagus cuniculus) in Australia, it appears that 1 + 1 = 2.1.

Pt tagged rab with RHD+myxo 1 10-08

Tagged European rabbit kitten infected with myxoma virus, but that died from rabbit haemorrhagic virus disease (RHDV). Photo by David Peacock, Biosecurity South Australia.

“Canberra, we have a problem” — Sure, it’s an old problem and much less of one than it used to be back in the 1950s, but invasive rabbits are nonetheless an ecological, conservation, and financial catastrophe across Australia.

relative rabbit abundance South Australia

Semi-schematic diagram, redrawn using data from Saunders and others and extended to include the recent spread of RHDV2, showing changes in rabbit abundance in relation to the introduction of biological control agents into north-eastern South Australia. Dotted lines indicate uncertainty due to lack of continuous annual data. The broken line indicates a level of about 0.5 rabbits ha-1, below which rabbits must be held to ensure recovery of native pastures and shrubs (from B. Cooke 2018 Vet Rec doi:10.1136/vr.k2105)

Rabbits used to reach plague numbers in much of agricultural and outback Australia, but the introduction and clever manipulation of two rather effective rabbit-specific viruses and insect vectors — first, myxoma virus in 1950, European rabbit fleas in the 1960s to help spread the virus, then Spanish rabbit fleas in the 1990s to increase spread into arid areas, and then rabbit haemorrhagic disease virus (RHDV) in 1995 — have been effective in dropping rabbit abundances by an estimated 75-80% in South Australia alone since the 1950s.

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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 »





My interview with Conservation Careers

10 04 2018

IMage-2

The online job-search engine and careers magazine for conservation professionals — Conservation Careers — recently published an interview with me written by Mark Thomas. Mark said that he didn’t mind if I republished the article here.

As we walk through life we sometimes don’t know where our current path will take us. Will it be meaningful, and what steps could we take? Seeking out and talking to people who have walked far ahead of us in a line of work that we are interested in could help shape the next steps we take, and help us not make the same mistakes that could have cost us precious time.

A phrase that I love is “standing on the shoulders of giants” and this conversation has really inspired me — I hope it will do for you as well.

Corey Bradshaw is the Matthew Flinders Fellow in Global Ecology at Flinders University, and author to over 260 hundred peer-reviewed articles. His research is mainly in the area of global-change ecology, and his blog ConservationBytes critiques the science of conservation and has over 11,000 followers. He has written books, and his most recent one ‘The Effective Scientist’ will be published in March (more on this later).

What got you interested in ecology and conservation?

As a child I grew up in British Columbia, Canada, my father was a fur trapper, and we hunted everything we ate (we ate a lot of black bear). My father had lots of dead things around the house and he prepared the skins for the fur market. It was a very consumptive and decidedly non-conservation upbringing.

Ironically, I learnt early in life that some of the biggest impediments to deforestation through logging was the trapping industry, because when you cut down trees nothing that is furry likes to live there. In their own consumptive ways, the hunters were vocal and acted to protect more species possibly than what some dedicated NGOs were able to.

So, at the time, I never fully appreciated it, but not having much exposure to all things urban and the great wide world, and by spending a lot of time out in the bush, I ended up appreciating the conservation of wild things even within that consumptive mind-set. Read the rest of this entry »





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.

CB_JackassPenguinsEcologicalTrapPhoto

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 »





Our global system-of-systems

28 02 2018

Complex-systems

I’ve just read an excellent paper that succinctly, eloquently, and wisely summarised the current predicament of our highly interconnected, global, complex adaptive system (i.e., our environment).

If you are new to the discussions around state shifts, hysteresis, tipping points, and system collapse, there might be a lot in the new paper by Philip Garnett of the University of York that you could find intimidating (and not just because of the complexity of the concepts he discusses). If you are more up-to-date on these discussions, I highly recommend reading this paper for distilling some of the more pertinent questions.

The essence of the paper is that our global environment (Earth) is one giant, complex system made up of interacting sub-systems. We can think of these as a giant, interconnected network of nodes and connections (often called ‘edges’) between them. If you do ecological network theory, then you know what I’m talking about.

What’s particularly fascinating to me is that Philip Garnett is not an environmental scientist; in fact, he’s a a lecturer in Operations Management and Business Analytics (although he does have a background in genetics and biology) who specialises in complex systems theory. In fact, much of his paper uses socio-economic examples of system complexity and collapse, yet the applications to environmentalism in general, and to ecological integrity in particular, are spot on.

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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.

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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 »