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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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 »





Noses baffled by ocean acidification

18 04 2017

Clown fish couple (Amphiprion percula) among the tentacles of anemone Heteractis magnifica in Kimbe Bay (Papua New Guinea) – courtesy of Mark McCormick. Clownfish protect anemones from predators and parasites in exchange of shelter and food. The fish tolerates the host’s venom because its skin is protected by a mucus layer some 2-3× thicker than phylogenetically related species (12); clownfish fabricate the mucus themselves and seem to obtain anemone antigens through a period of acclimation (13), but whether protection is acquired or innate is still debated. Clownfish are highly social bony fish, forming groups with one reproductive pair (up to 11 cm in length each) and several smaller, non-reproductive males. Reproduction is protandrous (also known as sequential hermaphroditism), so larvae are born male and, as soon as the reproductive female dies, her widower becomes female and the largest of the subsidiary males becomes the alpha male. The IUCN lists clownfish, generically named ‘anemone fish’, as threatened by the pet-trade industry and habitat degradation, although surprisingly, only 1 species has been assessed (A. sandaracinos). The clown anemone fish A. ocellaris is the species that inspired Nemo in the 2003 Academy-Award fiction movie – contrary to the logical expectation that the Oscars Red Carpet would generate support for conservation on behalf of Hollywood, of the 1568 species represented in the movie, only 16 % of those evaluated are threatened (14).

Smell is like noise, the more scents we breathe in one sniff, the more difficult it is to distinguish them to the point of olfactory saturation. Experimental work with clownfish reveals that the increase in dissolved carbon dioxide in seawater, mimicking ocean acidification, alters olfactory physiology, with potential cascading effects on the demography of species.

Places such as a restaurant, a hospital or a library have a characteristic bouquet, and we can guess the emotional state of other people by their scents. Smell is critical between predators and prey of many species because both have evolved to detect each other without the aid of vision. At sea, the smell of predators dissolves in water during detection, attack, capture, and ingestion of prey, and many fishes use this information to assess the risk of ending up crunched by enemy teeth (1, 2). But predator-prey interactions can be modified by changes in the chemical composition of seawater and are therefore highly sensitive to ongoing ocean acidification (see global measuring network here). Experts regard ocean acidification as the ‘other CO2 problem’ of climate change (3) — just to emphasize that anthropogenic climate-change impacts terrestrial and aquatic ecosystems alike. Acidification occurs because the ocean absorbs CO2 at a rate proportional with the concentration of this gas in the atmosphere and, once dissolved, CO2 becomes carbonic acid (H2CO3), which in turn releases protons (H+) — in simple terms, pH is the concentration of protons (see video about ocean acidification): Read the rest of this entry »





Job: Research Fellow in Palaeo-Ecological Modelling

13 04 2017

© seppo.net

I have another postdoctoral fellowship to advertise! All the details you need for applying are below.

KEY PURPOSE 

Scientific data such as fossil and archaeological records used as proxy to reconstruct past environments and biological communities (including humans) are sparse, often ambiguous or contradictory when establishing any consensus on timing or routes of initial human arrival and subsequent spread, the timing or extent of major changes in climate and other environmental perturbations, or the timing or regional pattern of biological extinctions.

The Research Fellow (Palaeo-Ecological Modelling) will assist in addressing these problems by developing state-of-the-art analytical and simulation tools to infer regional pattern of both the timing of human colonisation and megafauna extinction based on incomplete and sparse dataset, and investigating past environmental changes and human responses to identify their underlying causes and consequences on Australia’s landscapes, biodiversity and cultural history.

ORGANISATIONAL ENVIRONMENT 

The position will be based in the School of Biological Sciences in the Faculty of Science & Engineering at Flinders University. Flinders University boasts a world-class Palaeontology Research Group (PRG) and the new Global Ecology Research Laboratory that have close association with the research-intensive South Australian Museum. These research groups contribute to building a dynamic research environment that explores the continuum of environmental and evolutionary research from the ancient to modern molecular ecology and phylogeography. The School of Biological Sciences is an integrated community researching and teaching biology, and has a long history of science innovation. The appointee will join an interdisciplinary school of approximately 45 academic staff. The teaching and research activities of the School are supported by a range of technical and administrative infrastructure services.

KEY RESPONSIBILITIES

The key responsibilities and selection criteria identified for this position should be read in conjunction with the Flinders University Academic Profiles for the relevant academic classification (scroll down to Academic Profiles).

The Research Fellow (Palaeo-Ecological Modelling) will work under the direction of the Project Chief Investigator, and will be required to: Read the rest of this entry »





Limited nursery replenishment in coral reefs

27 03 2017
Haemulon sciurus

blue-striped grunt (Haemulon sciurus)

Coral reef fishes are wonderfully diverse in size, form, and function, as well as their need for different habitats throughout the life cycle. Some species spend all of their life in the same kind of coral habitat, while others need different places to breed and feed.

Fishes requiring different habitats as they progress through life often have what we call ‘nurseries’ in which adults lay eggs and the subsequent juveniles remain, and these places are often dominated by mangroves or seagrasses (i.e., they are not part of the coral reef).

While we’ve known for quite some time that when these nursery habitats are not around, adjacent coral reefs have few, if any, of these nursery-dependent species. What we haven’t known until now is just how far the influence of nurseries extends along a coral reef.

In other words, if a nursery is present, just how many new recruits do different areas of a reef receive from it? Read the rest of this entry »





Multiculturalism in the lab

23 02 2017

8294047fabf352ce46f4fd9a89d4a93dWith all the nasty nationalism and xenophobia gurgling nauseatingly to the surface of our political discoursethese days, it is probably worth some reflection regarding the role of multiculturalism in science. I’m therefore going to take a stab, despite being in most respects a ‘golden child’ in terms of privilege and opportunity (I am, after all, a middle-aged Caucasian male living in a wealthy country). My cards are on the table.

I know few overtly racist scientists, although I suspect that they do exist. In fact, most scientists are of a more liberal persuasion generally and tend to pride themselves on their objectivity in all aspects of being human, including the sociological ones. In other words, we tend to think of ourselves as dispassionate pluralists who only judge the empirical capabilities of our colleagues, with their races, genders, sexual persuasions and other physical attributes irrelevant to our assessment. We generally love to travel and interact with our peers from all nations and walks of life, and we regularly decorate our offices and with cultural paraphernalia different to our own.

But are we as unbiased and dispassionate as we think we are? Do we take that professed pluralism and cultural promiscuity with us to the lab each day? Perhaps we could, and should, do better. Read the rest of this entry »





Inexorable rise of human population pressures in Africa

31 08 2016
© Nick Brandt

© Nick Brandt

I’ve been a bit mad preparing for an upcoming conference, so I haven’t had a lot of time lately to blog about interesting developments in the conservation world. However, it struck me today that my preparations provide ideal material for a post about the future of Africa’s biodiversity.

I’ve been lucky enough to be invited to the University of Pretoria Mammal Research Unit‘s 50th Anniversary Celebration conference to be held from 12-16 September this year in Kruger National Park. Not only will this be my first time to Africa (I know — it has taken me far too long), the conference will itself be in one of the world’s best-known protected areas.

While decidedly fortunate to be invited, I am a bit intimidated by the line-up of big brains that will be attending, and of the fact that I know next to bugger all about African mammals (in a conservation science sense, of course). Still, apparently my insight as an outsider and ‘global’ thinker might be useful, so I’ve been hard at it the last few weeks planning my talk and doing some rather interesting analyses. I want to share some of these with you now beforehand, although I won’t likely give away the big prize until after I return to Australia.

I’ve been asked to talk about human population pressures on (southern) African mammal species, which might seem simple enough until you start to delve into the complexities of just how human populations affect wildlife. It’s simply from the perspective that human changes to the environment (e.g., deforestation, agricultural expansion, hunting, climate change, etc.) do cause species to dwindle and become extinct faster than they otherwise would (hence the entire field of conservation science). However, it’s another thing entirely to attempt to predict what might happen decades or centuries down the track. Read the rest of this entry »