Less snow from climate change pushes evolution of browner birds

7 09 2017
© Bill Doherty

© Bill Doherty

Climate changes exert selective pressures on the reproduction and survival of species. A study of tawny owls from Finland finds that the proportion of two colour morphs varies in response to the gradual decline of snowfall occurring in the boreal region.

Someone born in the tropics who travels to the Antarctic or the Himalaya can, of course, stand the cold (with a little engineering help from clothing, however). The physiology of our body is flexible enough to tolerate temperatures alien to those of our home. We can acclimate and, if we are healthy, we can virtually reside anywhere in the world.

However, modern climate change is steadily altering the thermal conditions of the native habitats of many species. Like us, some can live up to as much heat or cold as their genetic heritage permits, because each species can express a range of morphological, physiological, and behavioural variation (plasticity). Others can modify their genetic make-up, giving way to novel species-specific features or genotypes (evolution).

When genetic changes are speedy, that is, within a few generations, we are witnessing ‘microevolution’ — in contrast to ‘macroevolution’ across geological time scales as originally reported by Darwin and Wallace (1). To date, the detection of microevolution in response to modern climate change remains elusive, and many studies claiming so seem to lack the appropriate data to differentiate microevolution from phenotypic plasticity (i.e., the capacity of a single genotype to exhibit variable phenotypes in different environments) (2, 3). Read the rest of this entry »





Who are the healthiest people in the world?

8 05 2017

healthyApologies for the little gap in my regular posts — I am in the fortunate position of having spent the last three weeks in the beautiful Villa Serbelloni in the village of Bellagio on the shores of Lake Como (northern Italy) engaged in writing a new book with my good friend and colleague, Professor Paul Ehrlich. Both of us received an invitation to become ‘Bellagio Centre Residents‘ by the Rockefeller Foundation to write the book in, shall we say, rather lush circumstances.

While I can’t yet give away all the juicy details of the book itself (we’ve only written about a third of it so far), I wanted to give you a little taste of some of the interesting results we’ve so far put together.

Today’s topic is on human health, which as I’ve written many times before, is in many ways linked to the quality of the environment in which people live. We are currently looking at which countries have the best human health statistics, as well as the best environmental conditions in which to live. Read the rest of this entry »





Human population size: speeding cars can’t stop quickly

28 10 2014

Stop breeding cartoon-Steve Bell 1994Here at ConservationBytes.com, I write about pretty much anything that has anything remotely to do with biodiversity’s prospects. Whether it is something to do with ancient processes, community dynamics or the wider effects of human endeavour, anything is fair game. It’s a little strange then that despite cutting my teeth in population biology, I have never before tackled human demography. Well as of today, I have.

The press embargo has just lifted on our (Barry Brook and my) new paper in PNAS where we examine various future scenarios of the human population trajectory over the coming century. Why is this important? Simple – I’ve argued before that we could essentially stop all conservation research tomorrow and still know enough to deal with most biodiversity problems. If we could only get a handle on the socio-economic components of the threats, then we might be able to make some real progress. In other words, we need to find out how to manage humans much more than we need to know about the particulars of subtle and complex ecological processes to do the most benefit for biodiversity. Ecologists tend to navel-gaze in this arena far too much.

So I called my own bluff and turned my attention to humans. Our question was simple – how quickly could the human population be reduced to a more ‘sustainable’ size (i.e., something substantially smaller than now)? The main reason we posed that simple, yet deceptively loaded question was that both of us have at various times been faced with the question by someone in the audience that we were “ignoring the elephant in the room” of human over-population.

Read the rest of this entry »





You know it’s hot when it’s too hot to ….

16 01 2014
© T. Brandon

© T. Brandon

My post’s title might be a good candidate title for a punk song in the 2030s (maybe by a re-incarnation of the Dead Kennedys).

I am currently sitting under my solar-powered ceiling fan as Adelaide is declared the world’s hottest city (and not in the funky, cultural, fun way), and I can’t help but contemplate climate change models predicting the fate of biodiversity over the coming decades. Because it’s far, far too hot to work outside, I’m perusing the latest interesting articles on the subject and I came across this recent little gem.

Also recommended on F1000Prime by Ary Hoffman, the paper, Using physiology to predict the responses of ants to climatic warming, by Sarah Diamond and colleagues touches on many aspects of climate predictions that need to be considered. I summarise these briefly here.

While no physiologist, I have dabbled in the past, although up until quite recently I didn’t see that physiology per se had much to do with conservation. It turns out that climate change has spawned an entire sub-discipline called ‘conservation physiology‘, which focuses inter alia on how species can/will/might respond and adapt to a warmer, climatically disrupted world.

What struck me about Diamond & colleagues’ paper was that yet again, it’s not as simple as heat-stressing a species experimentally and making a prediction on its future distribution (ecology is complex). No, the complexity comes in various forms that makes each species a little different from each other. Using North American ant species subjected to various warming scenarios in large (5 m) enclosures, they found the following: Read the rest of this entry »