Spread among young families there is an ocean of baby clothes. When you’re expecting, you toss in a bucket and haul some out. When your child outgrows them, you try and throw them back, along with most of the new clothes you were given, like that hand-knitted jumper that junior refused to wear.
So just like any population, the amount of babyclothes in any house equals recruitment (gifts) plus immigrants (hand-me-downs), minus mortality (things thrown away), minus emigration (stuff you pass on).
What’d be most interesting would be to study the garments’ migratory patterns: Where do they go? How long do they survive? What’s the network structure?
You could investigate by setting up a labelling-and tracking system similar to Book Crossing or Where’s George?. People who had more than one child could also do mark-recapture studies, which gives me an excuse to mention my own pioneering work on the film direct Mike Leigh, something I am still rather pathetically proud of.
(Whenever I think about the ecology of everyday stuff, I think about this 1990 New Scientist article on the population biology of internal mail envelopes by Bill Sutherland.)
To desperately shoehorn in a proper science angle, this strikes me as being very slightly similar to the question of connectivity between coral reefs. One of the important topics in reef biology is understanding where the fish come from – are they born on the reef and stay there, or do they come from somewhere else? How much movement is there between reefs?
A dozen years ago, according to this paper, it was "generally assumed that larvae disperse away from their natal population so that local populations operate as 'open' systems, driven by recruitment of larvae from other sub-populations." But some studies (such as that one I just quoted, which looked at the fate of 10 million small fry on the Great Barrier Reef) find that many fish on a reef grew up there.
This varies, of course, depending on things such as how isolated a reef is, and understanding connectivity is a crucial question for reef conservation.
Showing posts with label ecology. Show all posts
Showing posts with label ecology. Show all posts
Thursday, August 18, 2011
Thursday, October 07, 2010
Chainsaw science
I have a review in this week's new-look Nature of Thomas Seeley's book Honeybee Democracy. (I wanted to call the piece 'The politics of dancing') It's a good read, and I think the last chapter on applying bee-rules to human decision making (one of the book's virtues is that Seeley doesn't over-claim in this regard) is worth anyone's time.
One thing I didn't mention in the review is that one of Seeley's early experiments involved roaming the woods with a chainsaw, looking for trees with bees, then chopping them down to measure the size of the cavity.
This made me think of Daniel Simberloff's work testing the predictions of island biogeography by manipulating the area of small Florida Mangrove islands with a chainsaw. E. O. Wilson describes the work in his memoir 'Naturalist'. (Clearly, the late 60s/early 70s were the golden age for chainsaws in ecology, as well as in Texan massacres.)
It made me think - how many other researchers have wielded a chainsaw in the name of science? I tried putting 'chainsaw' and 'chainsaw ecology' into google scholar, but most of the results pertain to studies of the effect of logging, which doesn't really count. There was one paper looking at the effect of chainsaw noise on spotted owls. I'm glad to see they seem to have used a real chainsaw, and not a recording, but again this is a study into the effects of logging. It'd be nice to put together a top ten of experiments that harnessed a chainsaw for scientific good, rather than looked at its evil effects.
One thing I didn't mention in the review is that one of Seeley's early experiments involved roaming the woods with a chainsaw, looking for trees with bees, then chopping them down to measure the size of the cavity.
This made me think of Daniel Simberloff's work testing the predictions of island biogeography by manipulating the area of small Florida Mangrove islands with a chainsaw. E. O. Wilson describes the work in his memoir 'Naturalist'. (Clearly, the late 60s/early 70s were the golden age for chainsaws in ecology, as well as in Texan massacres.)
It made me think - how many other researchers have wielded a chainsaw in the name of science? I tried putting 'chainsaw' and 'chainsaw ecology' into google scholar, but most of the results pertain to studies of the effect of logging, which doesn't really count. There was one paper looking at the effect of chainsaw noise on spotted owls. I'm glad to see they seem to have used a real chainsaw, and not a recording, but again this is a study into the effects of logging. It'd be nice to put together a top ten of experiments that harnessed a chainsaw for scientific good, rather than looked at its evil effects.
Tuesday, January 19, 2010
Climate-neutral ecology conferences
There's a piece in the latest TREE on how to have a carbon-neutral conference. The reference list also shows that emissions caused by conferences are an issue that several people have thought about. Sample title: Are international medical conferences an outdated luxury the planet can’t afford? Yes.
None of this is exactly new. And while local food, paper plates and so on are all better than nothing, I still think the answer is fewer meetings, not offsetting. "Most importantly," write Oliver Bossdorf and co, "[meetings] provide ample opportunities for networking." Well, so does the web, and you can do that at home.
None of this is exactly new. And while local food, paper plates and so on are all better than nothing, I still think the answer is fewer meetings, not offsetting. "Most importantly," write Oliver Bossdorf and co, "[meetings] provide ample opportunities for networking." Well, so does the web, and you can do that at home.
Thursday, August 13, 2009
Wikiecology
When I saw the graph on the front of today's technology Guardian, in an article about the slowing growth of Wikipedia (it's not in the online version), I thought: "That looks like a logistic growth curve. Perhaps the sum total of knowledge represents a resource that is being exhausted, causing the encyclopedia's growth to slow".
When I got to the end of the article, I discovered that the researcher behind the work being discussed, Ed Chi of PARC, had a similar thought.
But the article also says that the slowdown is caused by a shift in power towards 'deletionist' editors - it's getting harder to get stuff onto Wikipedia. Which suggests that the correct model might not be a sort of density-dependent, resource-limited population (we're running out of stuff to create wikipedia entries about), but perhaps something more top-down, like a predator-prey system (the editor population is keeping the contributor population in check).
I've no idea, but it's a question entirely suitable to the tools of ecological analysis. Someone should get onto it.
When I got to the end of the article, I discovered that the researcher behind the work being discussed, Ed Chi of PARC, had a similar thought.
"In my experience, the only thing we've seen these growth patterns [in] before is in population growth studies – where there's some sort of resource constraint that results in this model." The site, he suggests, is becoming like a community where resources have started to run out. "As you run out of food, people start competing for that food, and that results in a slowdown in population growth and means that the stronger, more well-adapted part of the population starts to have more power."
But the article also says that the slowdown is caused by a shift in power towards 'deletionist' editors - it's getting harder to get stuff onto Wikipedia. Which suggests that the correct model might not be a sort of density-dependent, resource-limited population (we're running out of stuff to create wikipedia entries about), but perhaps something more top-down, like a predator-prey system (the editor population is keeping the contributor population in check).
I've no idea, but it's a question entirely suitable to the tools of ecological analysis. Someone should get onto it.
Friday, May 01, 2009
Networks, finance and ecology
A couple of days ago, the FT reported on a speech by Andy Haldane, the Bank of England's head of financial stability:
What I think Haldane's talking about is the belief that more complex food webs were more stable, because diversity is, like, good. This was challenged by Bob May's famous 1973 finding that if you add links to a food web at random it actually becomes less stable the more complex it gets. SInce then, to quote a 2007 paper "the complexity–stability debate has been a central issue in ecology: does network complexity increase or decrease food-web persistence?"
And yet, to quote me, nature is full of large groups of species interacting in complex ways, and field and lab studies suggest that more complex, diverse ecosystems, in fact, show smaller fluctuations in their population sizes. So how's that work?
What ecology has shown us is that complexity per se isn't a disaster, so long as it's the right sort of complexity. Real food webs aren't random, and highly interconnected webs are in fact more robust to the removal of species - i.e. if one species/company goes extinct/bust, there isn't a cascade of other extinctions/bankruptcies. (This is Jennifer Dunne's work.)
The piece also says Haldane said that "the biggest and most interconnected banks should be subject to tougher regulations than smaller firms because they were most likely to be a super-spreader of financial risk. He likened them to heroin users or promiscuous homosexuals who were most likely to spread the HIV virus."
This is an allusion to the finding that small-world networks, such as the Internet, are robust to the removal of a random link, but very sensitive to the targeted removal of the best-connected links. This might be a bad thing in terms of cybercrime, but if you're trying to, say, stop disease spread, it can be turned to your advantage, because by targetting the best connected/most promiscuous individuals you can have a big impact on spread.
AIG, Citigroup etc., in other words, aren't too big to fail - they're too interconnected to fail.
Food webs are a bit different. In a study of the food webs of fish and plankton species living in lakes in the Adirondacks, Dunne and colleagues found that the species most vulnerable to extinction are the ones that result in the fewest secondary extinctions. This suggests, at least in the absence of human manipulation, that the structure of ecosystems maximizes biodiversity persistence. Researchers are now trying to deduce what shapes ecological networks into these robust configurations-forces such as natural selection or thermodynamic constraints on energy flows within the food web might each be at work.
So complexity per se isn't a bad thing. It's what you do with it that counts. Financially, what we need is to understand what makes a robust network, and then try and build that into the system - although that might not be compatible with everyone getting as rich as possible as quickly as possible. Then, although we won't see the shocks coming, we will be able to reduce their impact.
That's not to say the science is all neatly worked out. Haldane said that financial theory was a generation behind ecology. Which made me want to put my money under the mattress, because, although ecologists are getting some ideas about the general properties of ecological networks, food-web theory is still full of contradictory and disputed ideas. Still, maybe this will see a wave of ecologists following George Sugihara into finance, echoing the wave of maths and physics PhDs who became quants a decade or two ago. Remember how well that turned out?
Haldane's compete speech is here. (This post is based largely on the SFI Bulletin piece linked to above, 'Risk in Financial Markets - Learning from Nature' what I wrote (sound of own trumpet) 18 months ago.)
Financial risk management and regulation should cast aside many elements of traditional finance theory and learn lessons from ecology, the spread of diseases, biology and engineering, according to a senior Bank of England official...
[Haldane] likened financial mathematical models which "pointed to the stabilising effects of financial network completeness" to the now-discredited 1970s-style ecological orthodoxy that asserted the complex networks of enemies and parasites in rainforests would always guarantee their survival.
What I think Haldane's talking about is the belief that more complex food webs were more stable, because diversity is, like, good. This was challenged by Bob May's famous 1973 finding that if you add links to a food web at random it actually becomes less stable the more complex it gets. SInce then, to quote a 2007 paper "the complexity–stability debate has been a central issue in ecology: does network complexity increase or decrease food-web persistence?"
And yet, to quote me, nature is full of large groups of species interacting in complex ways, and field and lab studies suggest that more complex, diverse ecosystems, in fact, show smaller fluctuations in their population sizes. So how's that work?
What ecology has shown us is that complexity per se isn't a disaster, so long as it's the right sort of complexity. Real food webs aren't random, and highly interconnected webs are in fact more robust to the removal of species - i.e. if one species/company goes extinct/bust, there isn't a cascade of other extinctions/bankruptcies. (This is Jennifer Dunne's work.)
The piece also says Haldane said that "the biggest and most interconnected banks should be subject to tougher regulations than smaller firms because they were most likely to be a super-spreader of financial risk. He likened them to heroin users or promiscuous homosexuals who were most likely to spread the HIV virus."
This is an allusion to the finding that small-world networks, such as the Internet, are robust to the removal of a random link, but very sensitive to the targeted removal of the best-connected links. This might be a bad thing in terms of cybercrime, but if you're trying to, say, stop disease spread, it can be turned to your advantage, because by targetting the best connected/most promiscuous individuals you can have a big impact on spread.
AIG, Citigroup etc., in other words, aren't too big to fail - they're too interconnected to fail.
Food webs are a bit different. In a study of the food webs of fish and plankton species living in lakes in the Adirondacks, Dunne and colleagues found that the species most vulnerable to extinction are the ones that result in the fewest secondary extinctions. This suggests, at least in the absence of human manipulation, that the structure of ecosystems maximizes biodiversity persistence. Researchers are now trying to deduce what shapes ecological networks into these robust configurations-forces such as natural selection or thermodynamic constraints on energy flows within the food web might each be at work.
So complexity per se isn't a bad thing. It's what you do with it that counts. Financially, what we need is to understand what makes a robust network, and then try and build that into the system - although that might not be compatible with everyone getting as rich as possible as quickly as possible. Then, although we won't see the shocks coming, we will be able to reduce their impact.
That's not to say the science is all neatly worked out. Haldane said that financial theory was a generation behind ecology. Which made me want to put my money under the mattress, because, although ecologists are getting some ideas about the general properties of ecological networks, food-web theory is still full of contradictory and disputed ideas. Still, maybe this will see a wave of ecologists following George Sugihara into finance, echoing the wave of maths and physics PhDs who became quants a decade or two ago. Remember how well that turned out?
Haldane's compete speech is here. (This post is based largely on the SFI Bulletin piece linked to above, 'Risk in Financial Markets - Learning from Nature' what I wrote (sound of own trumpet) 18 months ago.)
Monday, October 13, 2008
Chainsaw massacre and the need for speed
This feature from yesterday's Observer on Britain's trees is worth a look. It's particularly good on the benefits and threats to urban trees, which was all new to me. When it looks at woodland, and efforts to restore it, I found myself wishing for a lot less Felix Dennis (flying over his woodland in his helicopter, talking nonsense on climate change) and a lot more (any) Oliver Rackham.
There's a sentence about how the Woodland Trust has found itself outbid when trying to buy land in southeast England that made me think of a recent Ecology Letters paper on how to work out when to buy land, weighing uncertainty of it's conservation against the need to buy it before someone else does.
Eve McDonald-Madden of the University of Queensland and her colleagues use a modelling technique called stochastic dynamic programming – often applied to animal foraging behaviour – which predicts what you should do at any given time, given what’s already happened. They come up with an optimal method for decision making, and a simpler rule of thumb which uses current knowledge of the sites conservation value, and the deadline on a decision, to give a deal-or-no-deal answer.
I guess this might not be so applicable in the UK, where pretty much everything is already surveyed, so conservation value is well known and budgets and land prices are the main issue. But perhaps it might help in prioritizing. And I thought it was a neat paper in general.
There's a sentence about how the Woodland Trust has found itself outbid when trying to buy land in southeast England that made me think of a recent Ecology Letters paper on how to work out when to buy land, weighing uncertainty of it's conservation against the need to buy it before someone else does.
Eve McDonald-Madden of the University of Queensland and her colleagues use a modelling technique called stochastic dynamic programming – often applied to animal foraging behaviour – which predicts what you should do at any given time, given what’s already happened. They come up with an optimal method for decision making, and a simpler rule of thumb which uses current knowledge of the sites conservation value, and the deadline on a decision, to give a deal-or-no-deal answer.
I guess this might not be so applicable in the UK, where pretty much everything is already surveyed, so conservation value is well known and budgets and land prices are the main issue. But perhaps it might help in prioritizing. And I thought it was a neat paper in general.
Friday, September 05, 2008
BES 2008
The last time I went to a British Ecological Society annual meeting, in 2006, I wrote a (remarkably long) post about how it was all a bit impenetrable and inward looking. I went to this year’s at Imperial on Wednesday and Thursday and had a much better time. Hopefully I'll get a few pieces written on the back of it.
The highlight was an excellent session on the impact of climate change on biodiversity and ecosystem services. Working out how species will respond to climate change is a big deal right now – and lots of ecologists are unhappy with the climate envelope models that look at the climate where something lives now, look at where that climate will be in 2100 (e.g. further north, higher up) and work out whether that’s a feasible journey. But there’s more to life than the weather – food, parasites, species interactions. Several of the talks tried to factor these into climate projections without becoming hopelessly complicated, and did a pretty good job.
(And ecosystem services seem massive right now in ecological research and environmental policy, at least in the UK. A couple of people made the point that policymaker’s enthusiasm for incorporating them into policy actually outstrips scientific understanding of how they contribute to human wellbeing. Lots of work for ecologists there, and lots of potential collaborations with social scientists.) The issue of how you value them – is money the only meaningful metric? was also touched upon.
And, wandering in and out of sessions, most stuff was pretty good. The only thing that I entirely failed to get my head around was any of the talks in the session on rapid human-induced evolutionary change, which sounded like it should be interesting, but was all over my head, with no clear take-home messages. I was peeved, because I should have stayed in the session on using phylogenetics to explain tropical diversity – Toby Pennington’s talk on trees, dispersal and speciation was excellent.
Anyway, the general feeling was that many UK ecologists are engaged with providing good science that is really relevant to our problems, and of getting that science across to decision makers, despite the inevitable need to compromise that’ll entail, in a way that they weren’t even a couple of years ago. And the science isn’t just boring cut-down-reeds-to-create-habitat-for-invertebrates kinda stuff, it’s an exciting blend of theory and data, getting a really fundamental questions – the relationship between ecological networks (food and mutualism webs) and ecosystem services being a prime example.
The BES also has an Ecology and Policy blog.
The highlight was an excellent session on the impact of climate change on biodiversity and ecosystem services. Working out how species will respond to climate change is a big deal right now – and lots of ecologists are unhappy with the climate envelope models that look at the climate where something lives now, look at where that climate will be in 2100 (e.g. further north, higher up) and work out whether that’s a feasible journey. But there’s more to life than the weather – food, parasites, species interactions. Several of the talks tried to factor these into climate projections without becoming hopelessly complicated, and did a pretty good job.
(And ecosystem services seem massive right now in ecological research and environmental policy, at least in the UK. A couple of people made the point that policymaker’s enthusiasm for incorporating them into policy actually outstrips scientific understanding of how they contribute to human wellbeing. Lots of work for ecologists there, and lots of potential collaborations with social scientists.) The issue of how you value them – is money the only meaningful metric? was also touched upon.
And, wandering in and out of sessions, most stuff was pretty good. The only thing that I entirely failed to get my head around was any of the talks in the session on rapid human-induced evolutionary change, which sounded like it should be interesting, but was all over my head, with no clear take-home messages. I was peeved, because I should have stayed in the session on using phylogenetics to explain tropical diversity – Toby Pennington’s talk on trees, dispersal and speciation was excellent.
Anyway, the general feeling was that many UK ecologists are engaged with providing good science that is really relevant to our problems, and of getting that science across to decision makers, despite the inevitable need to compromise that’ll entail, in a way that they weren’t even a couple of years ago. And the science isn’t just boring cut-down-reeds-to-create-habitat-for-invertebrates kinda stuff, it’s an exciting blend of theory and data, getting a really fundamental questions – the relationship between ecological networks (food and mutualism webs) and ecosystem services being a prime example.
The BES also has an Ecology and Policy blog.
Tuesday, January 22, 2008
The Mike Leigh mark-recapture experiment II
The discovery of Neptune. Gauss's calculations of the orbits of asteroids. The 1919 solar eclipse that caught light bending. Science is filled with masterly predictions, triumphantly confirmed.
Add a new one to the list.
In Sept 2006, I wrote, in a quite poorly punctuated post, of my repeat sightings of film director Mike Leigh around London. I suggested that Leigh could be a model for measuring the bumping-into-frquency of any two Londonders. And, based on three sightings, I ended the post with
Well, we were in the NFT on Sunday afternoon, queuing up to get tickets for The Lady Vanishes, and there he was, right in front of us in the queue!
Imagine my pleasure. Conclusive proof that any two Londoners (of similar cultural interests/socioeconomic level) can expect to cross paths just under every 18 months. I released the director back into the wild, to go on making his finely observed portraits of lower-middle-class desperation, secure in the knowledge of another encounter in summer 2009.
Add a new one to the list.
In Sept 2006, I wrote, in a quite poorly punctuated post, of my repeat sightings of film director Mike Leigh around London. I suggested that Leigh could be a model for measuring the bumping-into-frquency of any two Londonders. And, based on three sightings, I ended the post with
if you're reading this, Mr Leigh, I'll see you in 2008.
Well, we were in the NFT on Sunday afternoon, queuing up to get tickets for The Lady Vanishes, and there he was, right in front of us in the queue!
Imagine my pleasure. Conclusive proof that any two Londoners (of similar cultural interests/socioeconomic level) can expect to cross paths just under every 18 months. I released the director back into the wild, to go on making his finely observed portraits of lower-middle-class desperation, secure in the knowledge of another encounter in summer 2009.
Thursday, November 29, 2007
Ecologists rule (well, advise)
I see (belatedly) that John Beddington is going to be the UK government chief science adviser, succeeding David King in January. Beddington is an applied ecologist - specializing in fisheries biology. He'll be the second ecologist out of the past three science advisers - King's predecessor was the legendary Bob May (who, like Beddington, used to work at Imperial College London).
Add to this behavioural ecologist John Krebs' (who, I see, now has the magnificent title of Baron Krebs, making him sound as if he should be wearing a monocle and shooting down British biplanes over the Somme) chairmanship of the Food Standards Agency, and it looks as if ecologists are doing rather well at getting their mitts on the UK's levers of power. (And Krebs and May are now both at Oxford, making it basically an Imperial-Oxford operation).
Why is that? Within science, ecology doesn't strike me as a particularly powerful discipline, in terms of its level of jobs and funding. It's a lot more quantitative than, say, cell biology, which I guess is useful in government, but that doesn't seem like much of an argument. Maybe it's just a blip - May's predecessors were a microbiologist (William Stewart) and a computer engineer (John Fairclough).
Add to this behavioural ecologist John Krebs' (who, I see, now has the magnificent title of Baron Krebs, making him sound as if he should be wearing a monocle and shooting down British biplanes over the Somme) chairmanship of the Food Standards Agency, and it looks as if ecologists are doing rather well at getting their mitts on the UK's levers of power. (And Krebs and May are now both at Oxford, making it basically an Imperial-Oxford operation).
Why is that? Within science, ecology doesn't strike me as a particularly powerful discipline, in terms of its level of jobs and funding. It's a lot more quantitative than, say, cell biology, which I guess is useful in government, but that doesn't seem like much of an argument. Maybe it's just a blip - May's predecessors were a microbiologist (William Stewart) and a computer engineer (John Fairclough).
Thursday, September 13, 2007
Underground networking
Todays's Nature contains a News Feature by me (behind a paywall, I'm afraid), looking at the possibility that mycorrhizal fungi transfer nutrients between plants, and in the process undercut the above-ground competition between plants by robbing the rich to feed the poor - subsidizing plants less able to photosynthesize.
How, why and whether they do this is still uncertain and occasionally controversial. But everyone seems to accept that mycorrhizal networks do exist - namely, that a single fungus can link many plants, potentially of different species, creating a arena for a rich range of ecological interactions. It's just we're not sure what they are. But a bunch of people are doing their damnedest to find out. Mycorrhizal ecology looks like a funky (and fungi) field right now.
For a more technical (than my piece), but freely accessible introduction to this field check out this TREE paper.
How, why and whether they do this is still uncertain and occasionally controversial. But everyone seems to accept that mycorrhizal networks do exist - namely, that a single fungus can link many plants, potentially of different species, creating a arena for a rich range of ecological interactions. It's just we're not sure what they are. But a bunch of people are doing their damnedest to find out. Mycorrhizal ecology looks like a funky (and fungi) field right now.
For a more technical (than my piece), but freely accessible introduction to this field check out this TREE paper.
Thursday, August 16, 2007
Autumn colours and aphids
In a previous life, before I became a successful, respected and well-balanced science writer, I did a PhD on the evolution of soldier castes in aphids. Happy days (not).
In this life — in 1996, to be exact — I travelled to an entomology conference in Florence. There, at a session on aphid biology, a fellow grad student and more talented researcher than myself called Sam Brown gave a presentation, coauthored with his supervisor Bill Hamilton, on the idea that the autumn colours of trees were a signal to marauding aphids of the strength of their antiherbivore defences.
Bright colours, their argument went, were an honest signal: only well-resourced trees able to make lots of the secondary compounds that plants use to make themselves unpalatable to herbivores would be able to make them. And aphids flying around in the autumn, looking for somewhere to lay their overwintering eggs, would shy away from such vivid displays.
The debate on the worth of this neat hypothesis has rumbled along for more than a decade now. Sceptics have pointed out that yellow pigments were there all along, but are only revealed when the leaf takes back it’s chlorophyll — leaves don’t turn yellow, they unturn green. Also that red pigments have other potential uses, centred on protecting the leaf as the plant takes it apart, chemically speaking. The latest update comes from Lars Chittka and Thomas Döring, two researchers on sensory ecology writing in PloS Biology.
To put it crudely, C and D’s piece plugs a forthcoming paper (this link wasn’t working when I checked) by them looking at colour vision in aphids. They find that Brown and Hamilton might have been deceived by their human’s-eye view. Aphids (and all other herbivorous insects looked at so far) don’t have good vision in the red — so red leaves wouldn’t look anything special to them. And yellow is powerfully attractive — it tickles their green receptors even more so than green itself, and brings insects flocking: ‘If trees wanted to deter herbivorous insects using color, yellow leaf coloration is about the worst strategy they could pick,’ they write.
The piece does such a good job of pouring cold water on the notion that autumn colours are signals that their final (inevitable) conclusion — the good old cry of ‘more research is needed’ rings a little hollow. Speaking as a rampaging adaptationist, who thinks that Hamilton has a good claim to having been the most important evolutionarybiologist since Darwin, I think that’s a bit of a shame, but there you go, beautiful theories, ugly facts and all that.
The essay also has some nice bits of history, and a lovely first sentence: ‘Most living things don't turn beautiful when they senesce’. But some editor should have stopped the use of ‘fascinating’ twice in the first paragraph. I can work out whether something is fascinating or not. (And while we’re about it, can we have a ten-year moratorium on the use of ‘intriguing’ in science journalism? It’s just ‘interesting’ wearing a false moustache.)
In this life — in 1996, to be exact — I travelled to an entomology conference in Florence. There, at a session on aphid biology, a fellow grad student and more talented researcher than myself called Sam Brown gave a presentation, coauthored with his supervisor Bill Hamilton, on the idea that the autumn colours of trees were a signal to marauding aphids of the strength of their antiherbivore defences.
Bright colours, their argument went, were an honest signal: only well-resourced trees able to make lots of the secondary compounds that plants use to make themselves unpalatable to herbivores would be able to make them. And aphids flying around in the autumn, looking for somewhere to lay their overwintering eggs, would shy away from such vivid displays.
The debate on the worth of this neat hypothesis has rumbled along for more than a decade now. Sceptics have pointed out that yellow pigments were there all along, but are only revealed when the leaf takes back it’s chlorophyll — leaves don’t turn yellow, they unturn green. Also that red pigments have other potential uses, centred on protecting the leaf as the plant takes it apart, chemically speaking. The latest update comes from Lars Chittka and Thomas Döring, two researchers on sensory ecology writing in PloS Biology.
To put it crudely, C and D’s piece plugs a forthcoming paper (this link wasn’t working when I checked) by them looking at colour vision in aphids. They find that Brown and Hamilton might have been deceived by their human’s-eye view. Aphids (and all other herbivorous insects looked at so far) don’t have good vision in the red — so red leaves wouldn’t look anything special to them. And yellow is powerfully attractive — it tickles their green receptors even more so than green itself, and brings insects flocking: ‘If trees wanted to deter herbivorous insects using color, yellow leaf coloration is about the worst strategy they could pick,’ they write.
The piece does such a good job of pouring cold water on the notion that autumn colours are signals that their final (inevitable) conclusion — the good old cry of ‘more research is needed’ rings a little hollow. Speaking as a rampaging adaptationist, who thinks that Hamilton has a good claim to having been the most important evolutionarybiologist since Darwin, I think that’s a bit of a shame, but there you go, beautiful theories, ugly facts and all that.
The essay also has some nice bits of history, and a lovely first sentence: ‘Most living things don't turn beautiful when they senesce’. But some editor should have stopped the use of ‘fascinating’ twice in the first paragraph. I can work out whether something is fascinating or not. (And while we’re about it, can we have a ten-year moratorium on the use of ‘intriguing’ in science journalism? It’s just ‘interesting’ wearing a false moustache.)
Monday, July 16, 2007
Spontaneous order, fungal networks, and circuses
You wait ages to feel moved to post, and then three things come along at once. In no particular order…
Biological modularity can emerge as a spontaneous, self-organized process, say Ricard Solé and Sergi Valverde in J. R. Soc. Interface. By modularity they mean particular sets of interactions in the great web of biochemistry (rather than, say, organs):
Such a trend seems to call for an adaptive explanation. In particular, what seems to demand explanation are ‘motifs’ in these networks
Solé and Valverde cite a couple of adaptive explanations “based on a genetic programming approach”. But they don’t agree with them.
Instead, they say such modularity is the inevitable consequence of evolution by gene (or genome) duplication (“the driving force behind the evolution of complex organisms”, they say) followed by divergence, as evolution tinkers with the newly enlarged network of interactions (letting natural selection back in, it looks like)
I’ve clearly, as is my wont, become aware of this debate somewhere in the middle — the paper cites several is-modularity-evolution-or-is-it-self-organization? papers from the past few years. But, as far as I can tell, Solé and Valverde are saying that this is the first explanation for such modularity based on “fundamental, dynamical rules”.
In other network news, Proc R Soc B has just published a paper by Daniel Bebber et al. looking at fungal networks.
The challenges such a fungal mycelium faces are to explore its environment, exploit resources, transport them around the rest of the organism, and to be sufficiently robust to resist physical damage and the many fungus-eaters in the soil.
To investigate how fungi meet such challenges, they grew Phanerochaete velutina in the lab, growing it out from an inoculated lump of wood towards other lumps of wood. They found that the fungus began in exploratory mode, sending out lots of narrow filaments. But as it completed searching its environment it consolidated its resources into fewer, bigger bundles of hyphae, growing between maor resource patches, with more exploratory filaments in new territory, and crosslinks to provide some redundancy in the case of network damage. “Netowrk development”, say Bebber et al.
In other words, they’re stressing the diversity of different structures produced by flexibility and responsiveness to environmental variation, as much as whatever general laws such networks might have.
Philip Loring (who I believe blogs here) approaches questions of resilience, connectedness and persistence from a different angle in Ecology and Society. He proposes the circus as an icon of resilience, in that it has retained its identity while changing its contents — i.e. getting rid of freak shows and (mostly) animal acts.
The article, to my mind, contains a bit too much on the history of the circus, without exploring the implications of the circus-as-sustainability metaphor. Also, while ‘circus’ has survived for 200 years, most individual circuses haven’t. This is fine for institutions and systems, but not so much for species and ecosystems. But it’s a nice comparison.
Biological modularity can emerge as a spontaneous, self-organized process, say Ricard Solé and Sergi Valverde in J. R. Soc. Interface. By modularity they mean particular sets of interactions in the great web of biochemistry (rather than, say, organs):
Modularity is particularly obvious in cellular networks, where it can be detected at the topological level. These networks include the webs of interactions among proteins, genes, enzymes and metabolites or signalling molecules.
Such a trend seems to call for an adaptive explanation. In particular, what seems to demand explanation are ‘motifs’ in these networks
patterns of interconnections occurring in complex networks at numbers that are significantly higher than those in randomized networks.
Solé and Valverde cite a couple of adaptive explanations “based on a genetic programming approach”. But they don’t agree with them.
Instead, they say such modularity is the inevitable consequence of evolution by gene (or genome) duplication (“the driving force behind the evolution of complex organisms”, they say) followed by divergence, as evolution tinkers with the newly enlarged network of interactions (letting natural selection back in, it looks like)
I’ve clearly, as is my wont, become aware of this debate somewhere in the middle — the paper cites several is-modularity-evolution-or-is-it-self-organization? papers from the past few years. But, as far as I can tell, Solé and Valverde are saying that this is the first explanation for such modularity based on “fundamental, dynamical rules”.
In other network news, Proc R Soc B has just published a paper by Daniel Bebber et al. looking at fungal networks.
they have evolved to explore and exploit a patchy environment rather than ramify through a three-dimensional organism. Unlike all the other biological transport systems studied, the fungal network is not part of the organism, it is the organism.
The challenges such a fungal mycelium faces are to explore its environment, exploit resources, transport them around the rest of the organism, and to be sufficiently robust to resist physical damage and the many fungus-eaters in the soil.
To investigate how fungi meet such challenges, they grew Phanerochaete velutina in the lab, growing it out from an inoculated lump of wood towards other lumps of wood. They found that the fungus began in exploratory mode, sending out lots of narrow filaments. But as it completed searching its environment it consolidated its resources into fewer, bigger bundles of hyphae, growing between maor resource patches, with more exploratory filaments in new territory, and crosslinks to provide some redundancy in the case of network damage. “Netowrk development”, say Bebber et al.
involves over-production of links and nodes in the exploratory phase, followed by selection and positive reinforcement of some links and recycling of the remainder during the consolidation phase … A
similar sequence of events is apparent in the development of other biological transport networks including those formed by acellular slime moulds [and] foraging ant trails … and may well represent a universal feature of self-organized biological networks. However, in each of these systems, the final network structure is likely to represent a context-specific balance between the need for efficient transpor t, cost and robustness.
In other words, they’re stressing the diversity of different structures produced by flexibility and responsiveness to environmental variation, as much as whatever general laws such networks might have.
Philip Loring (who I believe blogs here) approaches questions of resilience, connectedness and persistence from a different angle in Ecology and Society. He proposes the circus as an icon of resilience, in that it has retained its identity while changing its contents — i.e. getting rid of freak shows and (mostly) animal acts.
Through the many forms they have taken over the last 150 yr, circuses have changed significantly while sustaining a singular identity. As a successful and enduring social system, their intriguing history exposes the nuances of sustainability theory, from resilience to pathologies, and illustrates that sustainability requires a complex dynamic between identity, tradition, and change.
The article, to my mind, contains a bit too much on the history of the circus, without exploring the implications of the circus-as-sustainability metaphor. Also, while ‘circus’ has survived for 200 years, most individual circuses haven’t. This is fine for institutions and systems, but not so much for species and ecosystems. But it’s a nice comparison.
Thursday, March 15, 2007
Oekologie #3
Here beginneth the third edition of the Oekologie blog carnival. Thank you everyone who took the time to send in posts. It was great to receive such a diverse bunch — we've got just about every group of organism and every part of the world represented, at scales ranging from the global to the backyard, and addressing just about every issue you can think of. So here we go…
Crime! Julie from The Human Flower Project has sent in a cool story on the banning of the Hungarian hovirag harvest. The hovirag is a snowdrop, sold in Hungary as a mark of coming spring, but now grievously over-picked (and with a street value somewhat greater than crack, apparently). The flower is also the source of the protein that, put into to GM potatoes, led to the controversy around the experiments by (Hungarian-born) Arpad Puzstai.
Deceit! GrrlScientist at Living the Scientific Life posts on a neat piece of mimicry — the moth that pretends to be a jumping spider.
Pestilence! Jennifer Forman Orth at the Invasive Species Weblog reports on beech bark disease, which involves an invasive insect infesting the tree, which leads to a fungal infection, which leads to trouble.
Meanwhile, showing that not you don't need to cross an international borders to be an invasive species, Paul Decelles at The Force that Through… points the finger at red cedar, a native of the eastern US now making trouble further west. And then defends his position.
Goats! Aydin at Snail's Tales discusses the impact of goats on the past and future vegetation of the Mediterranean. "If we want to return at least some of the land to its original, pre-grazing, pre-human state, the goats must go," he says.
The Mediterranean is interesting because it has diverse plant life, even though it has seen millennia of heavy human impact, suggesting that the plants have coevolved with people and their animals. (This has also equipped Mediterranean plants to do well in places like California and Australia.) But, of course, whether this flora was in place before people showed up — and if not, what was — is another matter.
That's enough exclamation marks.
Fish: Stephen Leahy at, um, Stephen Leahy points us to his story discussing the concept of peak fish — global catches have levelled off (not sure what's happened to global fishing effort, but it seems unlikely to have fallen), and may soon start falling.
Another option for providing seafood is fish farming. The US government has proposed to extend fish farming into federal waters, 3 to 200 miles offshore. But Lish at Science Ripsaw is worried it that this would deplete nutrients and increase pollution.
Oil: Tom Elko at Sky Blue Waters reports on the concerns around the environmental impact and property rights issues of the MinnCan pipeline. If built (which is looking likely) it would carry crude oil from Canadian oil sands (which are environmental and carbon-emissions bad news in themselves) to refineries in Minnesota.
Milk(weed): Miconia at A Neotropical Savanna meditates on Asclepia.
I know it's not a very scientific reaction, but…
Eeuuw: GrrlScientist reports on a blind, cave-dwelling Madagascan snake (that looks like a worm), rediscovered more than 100 years after the last known specimens were collected. They avoid the light, and sniff out their prey — the eggs and larvae of ants and termites.
Eeuuw II: The pygmy-hog-sucking louse (as a part-time copyeditor and punctuation geek, I place those hyphens with some confidence). Sticking up for the bloodsuckers at Endangered Ugly Things, Garfman makes the excellent point that every large, cuddly and charismatic species in danger of extinction also has (probably several) parasites that depend on it for their own survival. Coendangered is the technical term, apparently.
Mangroves: On the Ecological Society of America's blog, Edward Barbier has posted an authoritative guide to the issues surrounding the loss and restoration of mangrove forests, particularly regarding their ability to buffer against storm and tsunami damage.
Barbier — who has done lots of research into the interactions between development, mangroves and ecosystem services (the mangroves usually come off worse) — argues that the debate around the benefits and costs of replanting, that have followed from the 2004 Indian Ocean tsunami, is oversimplified.
Cheetahs: Over at Laelaps, Brian Switek highlights something that was new to me — Iranian cheetahs. Brian writes about the Wildlife Conservation Society's work to conserve this population.
(This also made me intrigued about another thing I know nothing about — what issues a US conservation organizations faces when it works in Iran — in terms of dealing with both the Iranian and US governments.)
Bats: Jennifer Pinkley at The Infinite Sphere discusses how the eastern pipistrelle's more catholic taste in habitat and roosts has made it "more adaptable to changing environmental pressures" than its close relative the gray myotis.
Microbes: Coturnix at A Blog Around the Clock alerts us to PLoS Biology's glut of papers on ocean microbial diversity (i.e. metagenomics). This is way-cool stuff right now (see also previous post on this blog).
Semantics: Matt at the Behavioral Ecology blog has sent in a post entitled 'Is rape adaptive?', which also discusses whether 'rape' is a good word to apply to forced copulations in (non-human) animals. The consensus appears to be not and, although I usually favour strong words and try to avoid jargon, I agree.
Celebrity: Mike at 10,000 birds muses on the ethics of twitching, and the motivations of twitchers. Naturalists, paparazzi, rubberneckers, or all of the above?
Memories: for me at least, with Jeremy Bruno, and the Voltage Gate's guide to tropical dry forest.
Jeremy mentions Guanacaste in Costa Rica, conservation success story (thanks to the idea of introducing large domestic herbivores to do the seed-dispersal job once done my extinct species), macroecological hotspot, and a place I visited while researching ITBOAH (I had to get a mention in somewhere). One of the remarkable things about Costa Rica is that this forest is about half-an-hour's drive from cloud forest containing a totally different set of species.
Global: John Feeny at Growth is Madness! muses on whether spreading the news that we're in the middle of the earth's sixth mass extinction since the Cambrian will help turn people on to conservation.
And Vbecer00 at Reconciliation Ecology also touches on the issue of how you get people to care in his/her post on, well, just about every issue in conservation — why do it, how to do it, and how to make it work.
Local: Join Dave Bonta at Via Negativa for a walk in the snow in Plummer's Hollow, and benefit from his sharp eyes. The man knows his neighbourhood, and his shrews.
Or, you could visit Wayne at Niches, and read his reports on the effects of heavy rains on the creeks on his property in Athens, Georgia.
And finally….
Personals: Johan Stenberg is in Sweden, feeling lonely. Cheer Johan up and join his journal club on insect-plant ecology, at (where else but the) Insect-Plant Ecology blog.
So there you have it. Oekologie — opening your minds, grossing you out, winding you up, bringing you together. Thanks again, and be sure to check out the next edition in a month's time on the Behavioral Ecology Blog.
Crime! Julie from The Human Flower Project has sent in a cool story on the banning of the Hungarian hovirag harvest. The hovirag is a snowdrop, sold in Hungary as a mark of coming spring, but now grievously over-picked (and with a street value somewhat greater than crack, apparently). The flower is also the source of the protein that, put into to GM potatoes, led to the controversy around the experiments by (Hungarian-born) Arpad Puzstai.
Deceit! GrrlScientist at Living the Scientific Life posts on a neat piece of mimicry — the moth that pretends to be a jumping spider.
Pestilence! Jennifer Forman Orth at the Invasive Species Weblog reports on beech bark disease, which involves an invasive insect infesting the tree, which leads to a fungal infection, which leads to trouble.
Meanwhile, showing that not you don't need to cross an international borders to be an invasive species, Paul Decelles at The Force that Through… points the finger at red cedar, a native of the eastern US now making trouble further west. And then defends his position.
Goats! Aydin at Snail's Tales discusses the impact of goats on the past and future vegetation of the Mediterranean. "If we want to return at least some of the land to its original, pre-grazing, pre-human state, the goats must go," he says.
The Mediterranean is interesting because it has diverse plant life, even though it has seen millennia of heavy human impact, suggesting that the plants have coevolved with people and their animals. (This has also equipped Mediterranean plants to do well in places like California and Australia.) But, of course, whether this flora was in place before people showed up — and if not, what was — is another matter.
That's enough exclamation marks.
Fish: Stephen Leahy at, um, Stephen Leahy points us to his story discussing the concept of peak fish — global catches have levelled off (not sure what's happened to global fishing effort, but it seems unlikely to have fallen), and may soon start falling.
Another option for providing seafood is fish farming. The US government has proposed to extend fish farming into federal waters, 3 to 200 miles offshore. But Lish at Science Ripsaw is worried it that this would deplete nutrients and increase pollution.
Oil: Tom Elko at Sky Blue Waters reports on the concerns around the environmental impact and property rights issues of the MinnCan pipeline. If built (which is looking likely) it would carry crude oil from Canadian oil sands (which are environmental and carbon-emissions bad news in themselves) to refineries in Minnesota.
Milk(weed): Miconia at A Neotropical Savanna meditates on Asclepia.
I know it's not a very scientific reaction, but…
Eeuuw: GrrlScientist reports on a blind, cave-dwelling Madagascan snake (that looks like a worm), rediscovered more than 100 years after the last known specimens were collected. They avoid the light, and sniff out their prey — the eggs and larvae of ants and termites.
Eeuuw II: The pygmy-hog-sucking louse (as a part-time copyeditor and punctuation geek, I place those hyphens with some confidence). Sticking up for the bloodsuckers at Endangered Ugly Things, Garfman makes the excellent point that every large, cuddly and charismatic species in danger of extinction also has (probably several) parasites that depend on it for their own survival. Coendangered is the technical term, apparently.
Mangroves: On the Ecological Society of America's blog, Edward Barbier has posted an authoritative guide to the issues surrounding the loss and restoration of mangrove forests, particularly regarding their ability to buffer against storm and tsunami damage.
Barbier — who has done lots of research into the interactions between development, mangroves and ecosystem services (the mangroves usually come off worse) — argues that the debate around the benefits and costs of replanting, that have followed from the 2004 Indian Ocean tsunami, is oversimplified.
Cheetahs: Over at Laelaps, Brian Switek highlights something that was new to me — Iranian cheetahs. Brian writes about the Wildlife Conservation Society's work to conserve this population.
(This also made me intrigued about another thing I know nothing about — what issues a US conservation organizations faces when it works in Iran — in terms of dealing with both the Iranian and US governments.)
Bats: Jennifer Pinkley at The Infinite Sphere discusses how the eastern pipistrelle's more catholic taste in habitat and roosts has made it "more adaptable to changing environmental pressures" than its close relative the gray myotis.
Microbes: Coturnix at A Blog Around the Clock alerts us to PLoS Biology's glut of papers on ocean microbial diversity (i.e. metagenomics). This is way-cool stuff right now (see also previous post on this blog).
Semantics: Matt at the Behavioral Ecology blog has sent in a post entitled 'Is rape adaptive?', which also discusses whether 'rape' is a good word to apply to forced copulations in (non-human) animals. The consensus appears to be not and, although I usually favour strong words and try to avoid jargon, I agree.
Celebrity: Mike at 10,000 birds muses on the ethics of twitching, and the motivations of twitchers. Naturalists, paparazzi, rubberneckers, or all of the above?
Memories: for me at least, with Jeremy Bruno, and the Voltage Gate's guide to tropical dry forest.
Jeremy mentions Guanacaste in Costa Rica, conservation success story (thanks to the idea of introducing large domestic herbivores to do the seed-dispersal job once done my extinct species), macroecological hotspot, and a place I visited while researching ITBOAH (I had to get a mention in somewhere). One of the remarkable things about Costa Rica is that this forest is about half-an-hour's drive from cloud forest containing a totally different set of species.
Global: John Feeny at Growth is Madness! muses on whether spreading the news that we're in the middle of the earth's sixth mass extinction since the Cambrian will help turn people on to conservation.
And Vbecer00 at Reconciliation Ecology also touches on the issue of how you get people to care in his/her post on, well, just about every issue in conservation — why do it, how to do it, and how to make it work.
Local: Join Dave Bonta at Via Negativa for a walk in the snow in Plummer's Hollow, and benefit from his sharp eyes. The man knows his neighbourhood, and his shrews.
Or, you could visit Wayne at Niches, and read his reports on the effects of heavy rains on the creeks on his property in Athens, Georgia.
And finally….
Personals: Johan Stenberg is in Sweden, feeling lonely. Cheer Johan up and join his journal club on insect-plant ecology, at (where else but the) Insect-Plant Ecology blog.
So there you have it. Oekologie — opening your minds, grossing you out, winding you up, bringing you together. Thanks again, and be sure to check out the next edition in a month's time on the Behavioral Ecology Blog.
Tuesday, February 27, 2007
Oekologie blog carnival
Just a reminder that this blog will be hosting next month's round of the Oekologie blog carnival. This follows the grand jobs done so for by Infinite Sphere and Perceiving Wholes.
So, for the period of Feb 15-March 14, please send me your favourite ecological and environmental blog posts by following this link. And I'll bring it to the world's attention, or at least that subsection of the world that reads this.
So, for the period of Feb 15-March 14, please send me your favourite ecological and environmental blog posts by following this link. And I'll bring it to the world's attention, or at least that subsection of the world that reads this.
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