One-two carbon punch of defaunation

30 04 2016

1-2 punchI’ve just read a well-planned and lateral-thinking paper in Nature Communications that I think readers of CB.com ought to appreciate. The study is a simulation of a complex ecosystem service that would be nigh impossible to examine experimentally. Being a self-diagnosed fanatic of simulation studies for just such purposes, I took particular delight in the results.

In many ways, the results of the paper by Osuri and colleagues are intuitive, but that should never be a reason to avoid empirical demonstration of a suspected phenomenon because intuition rarely equals fact. The idea itself is straightforward, but takes more than a few logical steps to describe: Read the rest of this entry »





Cartoon guide to biodiversity loss XXXIV

14 01 2016

Another six biodiversity cartoons for you this week. You might have asked yourself ‘Why six?’ — the number 6 is, of course, the smallest perfect number (i.e., the sum of its aliquot divisors is equal to the number itself: 1 + 2 + 3 = 6), and as a result, my favourite (geek). See full stock of previous ‘Cartoon guide to biodiversity loss’ compendia here.

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Cartoon guide to biodiversity loss XXXIII

18 11 2015

Six more biodiversity cartoons to hold you over until I get back from Germany next week (see full stock of previous ‘Cartoon guide to biodiversity loss’ compendia here).

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Cartoon guide to biodiversity loss XXXII

8 09 2015

Six more biodiversity cartoons — this time, from France. They’re in French to pay hommage to my hosts (and acknowledge their fanaticism for les bandes dessinées), but don’t worry, I’ve provided full translation (see full stock of previous ‘Cartoon guide to biodiversity loss’ compendia here).

“Biodiversity: More and more species threatened. The good news for you is that you’re not endangered. The bad news is that neither are we.” © Roulies

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Cartoon guide to biodiversity loss XXXI

9 07 2015

Fourth batch of six biodiversity cartoons for 2015, because I’m travelling and haven’t had a lot of time for a more detailed post (see full stock of previous ‘Cartoon guide to biodiversity loss’ compendia here).

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When human society breaks down, wildlife suffers

22 01 2015

bearGlobal human society is a massive, consumptive beast that on average degrades its life-support system. As we’ve recently reported, this will only continue to get worse in the decades to centuries to come. Some have argued that as long as we can develop our societies enough, the impact of this massive demographic force can be lessened – a concept described by the environmental Kuznets curve. However, there is little evidence that negative societal impact on the environment is lessened as per capita wealth exceeds some threshold; unfortunately environmental damage tends to, on average, increase as a nation’s net wealth increases. That’s not to say that short-term improvements cannot be achieved through technological innovation – in fact, they will be essential to offset the inexorable growth of the global human population.

So poor nations as well as the wealthy ones are responsible for environmental damage. Poorer nations often have ineffective governance systems so they fail to enforce compliance in environmental regulations, but wealthier nations often exploit a high proportion of their natural resources, with the inevitable environmental damage this entails. In some cases however, biodiversity can temporarily escape some of the ravages of society because humans either perceive the area to be too dangerous, or otherwise have no incentive to go there. There are some good examples of the latter, such as the vicinity around the Chernobyl nuclear reactor that melted down in 1986, or the Korean demilitarised zone.

In this vein, I just stumbled across an extremely interesting paper today published online early in Conservation Biology that describes trends in charismatic wildlife (i.e., big mammals) as the former Soviet Union collapsed in 1991 and societal breakdown ensued. The authors had access to an amazing dataset that spanned the decade prior to the collapse, the decade immediately following, and a subsequent decade of societal renewal. What they found was fascinating. Read the rest of this entry »





Individuals a population to conserve make

28 11 2012
Unique in its genus, the saiga antelope inhabits the steppes and semi-desert environments in two sub-species split between Kazakhstan (Saiga tatarica tatarica, ~ 80% of the individuals) and Mongolia (Saiga tatarica mongolica). Locals hunt them for their meat and the (attributed) medicinal properties of male horns. Like many ungulates, the population is sensitive to winter severity and summer drought (which signal seasonal migrations of herds up to 1000 individuals). But illegal poaching has reduced the species from > 1 million in the 1970s to ~ 50000 currently (see RT video). The species has gone extinct in China and Ukraine, and has been IUCN “Critically Endangered” from 2002. The photo shows a male in The Centre for Wild Animals, Kalmykia, Russia (courtesy of Pavel Sorokin).

In a planet approaching 7 billion people, individual identity for most of us goes largely unnoticed by the rest. However, individuals are important because each can promote changes at different scales of social organisation, from families through to associations, suburbs and countries. This is not only true for the human species, but for any species (1).

It is less than two decades since many ecologists started pondering the ways of applying the understanding of how individuals behave to the conservation of species (2-9), which some now refer to as ‘conservation behaviour’ (10, 11). The nexus seems straightforward. The decisions a bear or a shrimp make daily to feed, mate, move or shelter (i.e., their behaviour) affect their fitness (survival + fertility). Therefore, the sum of those decisions across all individuals in a population or species matters to the core themes handled by conservation biology for ensuring long-term population viability (12), i.e., counteracting anthropogenic impacts, and (with the distinction introduced by Cawley, 13) reversing population decline and avoiding population extinction.

To use behaviour in conservation implies that we can modify the behaviour of individuals to their own benefit (and mostly, to the species’ benefit) or define behavioural metrics that can be used as indicators of population threats. A main research area dealing with behavioural modification is that of anti-predator training of captive individuals prior to re-introduction. Laden with nuances, those training programs have yielded contrasting results across species, and have only tested a few instances of ‘success’ after release into the wild (14). For example, captive black-tailed prairie dogs (Cynomys ludovicianus) exposed to stuffed hawks, caged ferrets and rattlesnakes had higher post-release survival than untrained individuals in the grasslands of the North American Great Plains (15). A clear example of a threat metric is aberrant behaviour triggered by hunting. Eleanor Milner-Gulland et al. (16) have reported a 46 % reduction in fertility rates in the saiga antelope (Saiga tatarica) in Russia from 1993-2002. This species forms harems consisting of one alpha male and 12 to 30 females. Local communities have long hunted this species, but illegal poaching for horned males from the early 1990s (17) ultimately led to harems with a female surplus (with an average sex ratio up to 100 females per male!). In them, only a few dominant females seem to reproduce because they engage in aggressive displays that dissuade other females from accessing the males. Read the rest of this entry »








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