Increasing human population density drives environmental degradation in Africa

26 06 2019



Almost a decade ago, I (co-) wrote a paper examining the socio-economic correlates of gross, national-scale indices of environmental performance among the world’s nations. It turned out to be rather popular, and has so far garnered over 180 citations and been cited in three major policy documents.

In addition to the more pedestrian ranking itself, we also tested which of three main socio-economic indicators best explained variation in the environmental rank — a country’s gross ‘wealth’ indicator (gross national income) turned out to explain the most, and there was no evidence to support a non-linear relationship between environmental performance and per capita wealth (the so-called environmental Kuznets curve).

Well, that was then, and this is now. Something that always bothered me about that bit of research was that in some respects, it probably unfairly disadvantaged certain countries that were in more recent phases of the ‘development’ pathway, such that environmental damage long since done in major development pulses many decades or even centuries prior to today (e.g., in much of Europe) probably meant that certain countries got a bit of an unfair advantage. In fact, the more recently developed nations probably copped a lower ranking simply because their damage was fresher

While I defend the overall conclusions of that paper, my intentions have always been since then to improve on the approach. That desire finally got the better of me, and so I (some might say unwisely) decided to focus on a particular region of the planet where some of the biggest biodiversity crunches will happen over the next few decades — Africa.

Africa is an important region to re-examine these national-scale relationships for many reasons. The first is that it’s really the only place left on the planet where there’s a semi-intact megafauna assemblage. Yes, the great Late Pleistocene megafauna extinction event did hit Africa too, but compared to all other continents, it got through that period relatively unscathed. So now we (still) have elephants, rhinos, giraffes, hippos, etc. It’s a pretty bloody special place from that perspective alone.


Elephants in the Kruger National Park, South Africa (photo: CJA Bradshaw)

Then there’s the sheer size of the continent. Unfortunately, most mercator projections of the Earth show a rather quaint continent nuzzled comfortably in the middle of the map, when in reality, it’s a real whopper. If you don’t believe me, go to and drag any country of interest over the African continent (it turns out that its can more or less fit all of China, Australia, USA, and India within its greater borders).

Third, most countries in Africa (barring a few rare exceptions), are still in the so-called ‘development’ phase, although some are much farther along the economic road than others. For this reason, an African nation-to-nation comparison is probably a lot fairer than comparing, say, Bolivia to Germany, or Mongolia to Canada.

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A call to wings

19 03 2019

This week sees the launch of an updated bat synopsis from Conservation Evidence, adding new studies that have come out since the first synopsis was published in 2013.

The synopsis collects and summarises studies that test conservation actions such as ‘provide bat boxes for roosting bats’, and organises the studies by the action that they test. This focus on solutions makes it a handy point of reference for conservationists wishing to see what might work — and what is unlikely to work — to conserve bats.

Bechstein’s bat – photo credit Claire Wordley

Bechstein’s bat (Myotis bechsteinii) — photo credit Claire Wordley


Free to read or download from Conservation Evidence, the update represents a major addition to the original, containing 173 studies to the original 101. Studies are included if they tested an action that could be put in place for conservation, and measured an outcome for bats. As well as adding studies published from 2013 on, the update adds studies originally published in Spanish or Portuguese, and it is hoped that more languages will be added in future editions. Read the rest of this entry »

Dangers of the global road-building tsunami

8 06 2017

New roads can be treacherous — even fatal — for wildlife, native forests, and the global environment.

If you don’t believe this, just watch this two-minute video, “Why Roads Are So Dangerous

New roads can also be surprisingly risky for human economies and societies, as shown in this brief video, “Why Roads are Like Pandora’s Box”.

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Guilty until proven innocent

18 07 2013

precautionary principleThe precautionary principle – the idea that one should adopt an approach that minimises risk – is so ingrained in the mind of the conservation scientist that we often forget what it really means, or the reality of its implementation in management and policy. Indeed, it has been written about extensively in the peer-reviewed conservation literature for over 20 years at least (some examples here, here, here and here).

From a purely probabilistic viewpoint, the concept is flawlessly logical in most conservation questions. For example, if a particular by-catch of a threatened species is predicted [from a model] to result in a long-term rate of instantaneous population change (r) of -0.02 to 0.01 [uniform distribution], then even though that interval envelops r = 0, one can see that reducing the harvest rate a little more until the lower bound is greater than zero is a good idea to avoid potentially pushing down the population even more. In this way, our modelling results would recommend a policy that formally incorporates the uncertainty of our predictions without actually trying to make our classically black-and-white laws try to legislate uncertainty directly. Read the rest of this entry »

Perceptions on poverty: the rising Middle Class

16 03 2009

I’m being somewhat ‘lazy’ this week in that I have unfortunately less time to spend on pertinent blog posts than I’d like (lecturing, looming deadlines, that sort of thing). So, I start out this week’s posts with one of my favourite TED talks – Hans Rosling debunks myths about the developing world.

What’s the relevance to biodiversity conservation? I’ll admit, it may appear somewhat tangential, but there are a few important messages (both potentially good and bad):

1. POSSIBLE BENEFIT #1: The rising wealth in the developing world and associated reduction in family size may inevitably curb our human population growth rates;

2. POSSIBLE DISADVANTAGE #1: Rising wealth will necessarily mean more and more consumption, and as we know at least for tropical developing nations, resource consumption is killing biodiversity faster than anywhere else on the planet;

3. POSSIBLE DISADVANTAGE #2: As family wealth rises, so too do opportunities do opportunities for the Anthropogenic Allee effect (consuming rare species just because you can afford to do so);

4. POSSIBLE BENEFIT #2: Better health care associated with rising wealth and lower infant mortality might make education a higher priority, teaching more people about the necessity of safeguarding ecosystem services.

I’m not convinced the advantages will necessarily outweigh the disadvantages; regardless, Prof. Rosling’s amazing 20-minute presentation will both entertain and enlighten. I recommend it for a lunchtime sitting or that late-afternoon attention wain.

CJA Bradshaw

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