SciBlogs

Archive November 2009

More reptiles- garden skink photos Brendan Moyle Nov 30

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Going from saltwater crocodiles to NZ garden skinks is a bit of a change. One is the largest living reptile on the planet. The other is small and harmless.

I’ve been wanting to get some good shots of skinks taken for a while. The problem really is just the lighting. With a standard hot-shoe flash (even fired off-camera) you really get a lot of harsh shadows forming that envelope the detail.

This time round, I was using my ringlight flash with the macro lens to diffuse and spread the light more evenly. Hot spots are still inevitable because of the very shiny nature of the scales.

One of the interesting things about NZ lizards, is that almost all of them are viviparous. That means, they give birth to live young. It’s thought this was an adaptation to the various ice-ages in NZ. Being on island, the lizards didn’t have the chance to migrate to warm areas, then recolonise the cold areas when temperatures swing back. So eggs are developed within the body of the skink. This does tend to mean a low fecundity rate however.

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A quick and dirty guide to Global Warming for NZ Brendan Moyle Nov 27

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Now that NZ has amended the Emissions Trading Scheme legislation, ahead of the Copenhagen Meeting, I thought I’d try to make some sense of what all the fuss is about. This may be of limited value because I’m no expert myself.

Question 1: What’s Going On In The Atmosphere?

The simple answer is that we’ve front-loaded the carbon cycle. Lots of carbon it turns out, was stored as coal, natural gas and oil. And lots of carbon used to be stored as trees in tropical rainforests. So what we’ve done is abruptly release lots of that stored carbon (and associated gases) into the atmosphere.

Question 2: What’s going to happen?

There seems to be pretty wide agreement that we’re going to overshoot historical CO2 saturations (considered benign for human life). There is some uncertainty over what this means. But a lot of the projections are enough to make a lot of people, really, really nervous. It’s hard to see that this overshoot will be a good thing.

Question 3: What’s all the talk about Kyoto mean?

In the Kyoto meeting, various developed countries agreed to try to base their GHG emissions on 1990 levels. For NZ, this agreement had a few of fish-hooks.

First, it treated the release of stored carbon (from coal or oil or tropical rainforests) as the same problem as current carbon cycles from agriculture. So growing food as treated as a ‘bad’ in the same way as a roadtrip from LA to Las Vegas to visit the strip clubs is a ‘bad’.

Second, within agriculture, subsidised systems like Europe were treated on par with NZ unsubsidised systems. So our starting point was yeah, it’s okay if the EU wants to pay its farmers to exacerbate the emissions problem. This is also what is called putting ourselves at a competitive disadvantage. Or just a plain dumb move.

Third, the forestry fish-hook. If trees get chopped down in NZ to generate building materials, all the carbon in those trees is assumed to be released when they’re chopped down. Of course, it’s actually really locked up as furniture or floor boards. But this is a neat accounting trick to inflate our GHG emissions.

Question 4: So Why Did We Ratify Kyoto?

We assumed we’d be winners. In the early 1990s, people were planting trees like crazy in NZ. The reason was US federal law had just closed down most of the Pacific NW old growth forests. This was to protect spotted owls. So with a big fall in US timber exports, demand for NZ logs soared. Increases in forest areas meant we thought we’d be a winner.

Question 5: Why did everyone else sign Kyoto?

Everybody who signed Kyoto got all the credibility and warm glow for looking like they were doing something. But Kyoto didn’t mandate any action. So Kyoto frontloaded the political benefits to the signees, and backload all the adjustments costs on to Governments 10+ years down the track. Easy political win for the politicians of the time. What effect did Al Gore have on US emissions while he was VP?

Question 6: Why have we become losers in the GHG global game?

People in NZ stopped planting forests. They hit a hiccup in the 1997 Asian crisis. But this got worse from 2000 onwards. The combination of a high exchange rate and high interest rates killed off planting rates. Land-owners converted forests to dairy farms. And the government increased uncertainty for forestry investors by picking several fights with the sector. We actually ran into a deforestation problem.

Question 7: Why have the ETS?

The Emissions Trading Scheme is NZ’s device to lower our GHG emissions. The reality is that the only way GHG emissions can come down, is if households decide they’re okay with being made worse off. So the policy problem is finding a way that makes people worse off- that they’ll agree to.

We actually have to take a bigger hit on our costs to make a difference. The global energy subsidy is about $US 300bn a year. This is a device many countries to pay their citizens to use fossil fuels. So unsubsidised countries have to take a hit of say, over $US 300 bn a year on our energy costs before we can start making a difference. The same thing applies to various countries that subsidise deforestation or subsidise inefficient agricultural systems.

So part of the GHG problem is that for years, various countries have been spending hundreds of billions of dollars on ways to make it worse. The solution is of course, if you live in an unsubsidised country, you get to pay even more costs to offset this. Great huh?

Question 8: Will the ETS work?

The problem we run into is that the global objective isn’t to reduce NZ’s emissions. The global objective is to reduce global emissions. That creates a massive, international coordination problem. If we include agriculture before anyone else, there’s a risk that less efficient (more GHG emitting pastoral economies) will get a market advantage. We have less cows, someone worse than we are has more cows. Emissions could go up.

This is the Achilles Heel of the ETS. It has to work internationally and in a way that coordinates all players. NZ doesn’t live in an isolated box.

Question 9: Aren’t we subsidising polluters?

This point shifts the argument away from outcomes to equity (and has a quaint flypaper theory of costs). If our efficient exporters lose market share because they enter an ETS before other countries, then global emissions could rise. There’s no point feeling all virtuous if we don’t get a global reduction in emissions.

The second I’m afraid, is that the polluter-pays principle is somewhat naive and quaint as theories go. Households always end up paying some of these costs- doesn’t matter if charges are put on them or polluters. You can’t immunise households from the costs of pollution reduction- it might be in terms of higher product prices, or lost income opportunities, or less national income or the like. Ever noticed that when taxes go on to beer, wine and spirits that the breweries push up product prices? Costs will get passed on. You can’t isolate households from these effects. Polluter pays is a slogan, not an economic reality.

Question 10: If I was Emperor of the World?

First, carbon taxes. Implement carbon taxes with offsetting reductions in income and profit taxes. It’s easy to understand, the incentives to use less carbon are transparent, and you can reduce the financial costs by tax offsets. And it doesn’t require the same level of international coordination. Taxing carbon is no less arbitrary than taxing people’s labour.

Second, end energy and deforestation subsidies. Seriously, why are we being asked to swallow big costs to allow other countries to happily make the problem worse?

Australian magpie geese photos Brendan Moyle Nov 26

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Magpie geese are reasonably common around the waterways of the NT. Alas, my visit wasn’t at the time of the year when they had their finest plummage. In other parts of Australia they are much rarer, partly a result of loss of habitat.

Naturally, I had to try for some photos while I was there.

#1 Sole Flyer

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This is actually a very hard photo to get- simply because finding a lone flying goose is very difficult.

#2 Tandem

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Getting both birds in focus at the same time, is also a challenge.

#3 Wingmen

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Crocodiles- a conservation success story- Part IV Brendan Moyle Nov 25

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This continues my series on crocodile conservation- previous Part III is here.

The take-home lessons from the crocodile management programme for conservation, are pretty much that’s okay to try new stuff out. Being too timid creates its own costs. Second, a lot of research on sustainable-use is overly pessimistic. That pessimism derives from assumptions about the fixed nature of the growth function, and the homogeneity of the wildlife product.

What made the crocodile story was also that the advocates the scheme, got it wrong. This was a programme that was going to use crocodile leather to get people to conserve wild crocodiles.

What actually emerged was a industry built around several value-points. Nobody predicted that a meat industry would also emerge- or that crocodile-tourism would emerge as a new industry. The explanation for this lies in what is sometimes called dispersed knowledge. Lots of people know lots of different things. They could have no connection at all to conservation, but say, know something about marketing. Or have an inkling about how to sell a new product. Or they might have private information about where crocodiles are. Aborigines knew about the female-dominance effect on nest sites- long before the Western scientists did. That is another piece of information that feeds into the success of the sustainable use programme.

All this information is dispersed over these people, and policy makers can’t get to it. Most of this information wouldn’t even considered relevant without a change in policy. Some of the information could be incomprehensible. Aboriginal knowledge about crocodiles isn’t packaged together as a neat biological model. It has the form of myth and beliefs.

So, whether by accident or design, the sustainable use programme set in place a chain of events, when suddenly of this dispersed knowledge became relevant. It was employed by people to find solutions (and people are still seeking solutions to the challenges and opportunities). Crocodiles developed multiple values, and people started to see them as iconic (rather than a pest).

There is another take-home lesson for conservation here. It’s that you are never going to find all the relevant facts before you begin. And the important thing isn’t necessarily the information people have, it’s their motivation to employ it. This comes back almost full circle to my first post. Conservation is a discovery process. Think of it that way, test the boundaries and try new ideas out. Conservation is not a prescriptive process. You’re not going to be able to find out everything you need to know- and plan to a fine level of detail- the solution to all the problems.


Origin of the Species- 150 Years On Brendan Moyle Nov 24

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November 24 1859 marks the date that Darwin published the Origin of the Species. As a student, I don’t think you ever appreciate just what a brilliant piece of scientific work this was. It’s all diluted down and given to you in textbook summaries. And it always seemed so obvious. It’s only by reading the the Origin of the Species that you come to appreciate what an achievement it was.

Consider the basic argument for natural selection-
* Organisms have lots of offspring, most of which don’t survive
* Offspring manifest variations, some of which assist survival
* Assuming there is a mechanism for passing these good variations along, these will be selected for and become more frequent.
* Given enough time, new species emerge

The really clever thing here, is that there was no known mechanism to pass on successful traits when Darwin wrote this. There wasn’t any modern genetic theory lying around, waiting to be used. There wasn’t even really a rudimentary theory. Darwin effectively used the observations he made about the natural world to make a tacit prediction. There must be a means by which successful traits get passed on.

This remarkable scientific insight anticipated the modern genetics (1930s). It’s an insight that had to come out of knowing absolutely nothing about genetics and the mechanisms of inheritance. How did Darwin get it right? Essentially, by accumulating lots of evidence that could drive this insight.

He also made the correct inference on how old the Earth was. Again, this is a function of just seeing the world all around him. And initially, physics thought Darwin was wrong. Lord Kelvin calculated the age of the earth based on its temperature and came up with a figure much smaller than Darwin envisaged. In the end, Darwin was proved right. The answer lay not in Kelvin’s calculations, but his ignorance of radioactive elements. These create hotspots in the earth’s crust, changing the earth’s temperature dynamics completely.

Again, as a student you never really appreciate the brilliance contained in this book. Imagine just looking at a bunch of Galapagos Finches and going, you know, that must mean that modern genetics is just around the corner, and the Earth must be a heck of a lot older than we think. And being right.

What made Darwin’s book so compelling? It was not just the logic of the argument above. It was the catalogue of evidence accumulated over decades presented in the book, that helped convince many. It wasn’t just the finches, but decades of work, patiently gathering information.

Despite popular belief, Darwin didn’t overthrow the creationist model of biology. This had been gradually abandoned by many natural scientists already. The evidence of a loving, God who designed wildlife to fit their environment, was just not around to found. The evidence of mass extinctions in the fossil record, implied a far crueler and more capricious God than that of the bible. And the principle of design had taken a large knock when European animals were released into places like Australia. Rather than Australian animals being superbly designed for that niche, many such natives succumbed to the invasive species brought by people.

What Darwin did was to provide a mechanism on how organisms speciate. But natural selection was not the only contribution of the Origin. Sexual selection is another important mechanism. Male forms of some species have an appearance that is linked to partner preference. One of these examples is with NZ Harvestmen (or Opilionids). We actually have some polymorphic species.

NZ Stout-Legged Harvestman


Males can have two forms, not one. Why? One has very elaborate and outsized pedipalps. Hunting success is hindered, but females prefer to mate with such forms. The other form is more like the females. This form is a more successful hunter, but a less successful mater. There is a lovely, evolutionary equilibrium between these two forces that actually allows both forms to persist. One’s a more successful hunter, one’s a more successful suitor.

There are few scientific books that have ever had quite the same effect on the world as the Origin of the Species. It has gone on to influence our thinking about genetics and the mechanisms of inheritance, it drives conservation efforts, it underpins ecology, it influences human biology and behaviour and hence medicine. So, it is worth remembering on its 150th anniversary.

Crocodiles- a conservation success story- Part III Brendan Moyle Nov 23

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This continues the post on Tuesday on crocodile conservation

Last post I discussed why many conservation models of harvest were overly pessimistic. Conservation through sustainable use, could and did work. This post moves onto the poaching issue.

"…a future Hermes Bag?"


In the immediate post-war period, crocodiles in the North of Australia were heavily hunted. Harvest levels were in excess of financial considerations, because crocodiles were also regarded as a pest. That meant people still went out and shot them, even if their hunting costs exceeded the return on leather. The population of crocs shrank to about 5% of their pre-harvest levels.

In response to this, West Australia, the Northern Territory and Queensland began to ban harvests to protect crocodile numbers. This wasn’t coordinated, so poaching occurred in some states that had banned hunts, and the skins smuggled into other states that had not.

The fear that a resumption in the skin-trade would lead to increased poaching again seemed realistic. The argument is easy to understand. Suppose we have a wildlife product, and there are two ways to obtain it. You could have someone poach it at presumably low cost (small boat, rifle, sharp knife) or you could ranch or farm it. Ranching and farming involves big expenses- pens to house the animals, food for the crocs, staff to manage the population.

On this basis, it seemed clear that poaching would remain more attractive than ranching crocodiles. One operation is very low cost, one operation has much higher costs.

The fallacy in the argument is one that is often employed. The fallacy is that wildlife products are homogenous. I have a suspicion this follows from many wildlife harvest models being based on fisheries models. Fish tends to be reduced to a standard price per unit weight. Terrestrial wildlife however, can vary greatly in quality. Hermes and other luxury producers don’t want poached leather. It’s low grade and has many flaws. Crocs living in the wildlife get their skin scratched and scarred. This destroys the value of their skin. Crocs on farms and ranches, are much higher quality. This gets around the cost issue.

In fact, wildlife products are often characterised by wide price-dispersion. Goliath butterflies in Papua New Guinea can vary in price from 1 kina to 30 kina. It’s all based on the quality of the specimen.

Poaching of crocodiles (for commercial gain) has been pretty much extinguished in Australia. The legal market has drowned the illegal market in a flood of high quality, high volume, uniform skins.


White Heron Photos Brendan Moyle Nov 20

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Alas most of this week has been absorbed by that task known as grading. That doesn’t contribute to cogent and articulate blog posts. So, I’m reverting to the good old standby of bird photos instead :)

#1 White Heron in flight


#2 White Heron in flight


#3 White Heron- Fogg Dam


#4 White Heron- Fogg Dam


All photos taken up in the NT of Australia

Today’s Crocodile Photo Brendan Moyle Nov 18

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This shot reveals a of finer detail in the mouth. You can spot that one of the teeth in the front is in the process of growing back, and that the tongue isn’t all that smooth :)


Link to larger image

Crocodiles- a conservation success story- Part II Brendan Moyle Nov 17

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This continues my earlier post on crocodile conservation.

An important factor behind the successful sustainable-use conservation programme was the fact that crocodiles lacked charisma. They weigh hundreds of kilograms, are efficient and deadly carnivores, and have no qualms at all about predating on people. In short, nobody was going out into these river areas and trying to convince people that crocodiles were worth saving because they were so cute. In the end, the argument came down to, save crocodiles because they’re worth money.



That meant we had to find ways to make crocodiles worth money to locals. The obvious component of this was leather. Crocodile leather is used to make a variety of luxury products, including very expensive Hermes bags.

But what happened next, nobody predicted. This is what makes this story so fascinating from a conservation perspective. Everybody got it wrong. Critics of this programme in the early 80s said it would lead to over-harvest and poaching. Advocates never predicted that a crocodile meat industry would evolve out of the leather industry. They did not predict that a tourism industry would emerge out of this. And they certainly didn’t predict that crocodiles would attain an iconic status in the north, and win much wider acceptance by people.

What the programme was designed to do was mobilise economic forces behind conservation efforts. Unfortunately, the use of economic forces is something that is conspicuously neglected in conservation education programmes. I learned exactly one model that looked at this in my graduate ecology classes. This model was that of optimal extinction. Crudely put, this predicted that if a species population growth rate was less than the interest rate, harvesters would be impelled to wipe out the species and put the money in the bank. This is often the only formal model taught in most graduate conservation classes even today.

Crocodiles were believed to fit this model of optimal extinction well. They took until 25-30 years to reach maturity, and the population grew relatively slowly. So, unleashing any kind of harvest regime on crocodiles again, was predicted to lead to the catastrophic hunting of the 50s and 60s.

In fact, the opposite outcome was achieved. The reason is simply that the model of optimal extinction gets lots of things wrong. It assumes that harvesters are morons. This is done through the logistic population growth equation. The logistic functions takes the birth and mortality rate as fixed. And it takes carrying capacity of the habitat (how much wildlife can be supported) as fixed. In short, the opening assumption is that people are too thick to manage any of these parameters. Farming and ranching of crocodiles has already been ruled out as management option, as this will cause reproductive success to soar. And that can’t happen according to this model.

There are a lot of other things wrong with it too. The model assumes your wildlife has no age or sex structure, so there’s no point shifting harvests away from adults towards eggs and juveniles. There are some pretty dubious assumptions on the cost side as well.

At a biological level however, it is easy to see why crocodiles could be managed this way. Eggs have an extraordinarily high mortality rate (often by flooding). So removal of eggs has little impact on wild populations. Most would have died anyway. Shifting harvest away from a cohort with low mortality levels to high mortality levels kept harvest within ecological boundaries.

In order to get crocodiles eggs however, you need functioning and growing wild populations. Crocodiles also ‘nest’ according to female dominance. Dominant females go first. Aborigines already knew this. So, if you increase the area available for nest sites (say by fencing off areas from stock), then you got a fast payoff. The less dominant females would then have room to make their nests. More females would start nesting. Wild population growth rates start to take off.

This is basically what we observed. By making crocodiles valuable, human agents invested in management techniques to raise ‘carrying capacity’ and ‘growth rate’ constraints. This was a much stronger effect than the loss of eggs on the population.







Where the crocodiles are Brendan Moyle Nov 16

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Some film (Kodak portra 160VC) shots of the area of crocodile habitat we were photographing in.
While this is technically a fresh-water river, there are plenty of ‘salties’ about. Saltwater crocodiles are a bit of a misnomer- these reptiles can venture quite deep into fresh-water zones.









These I think, do a good job of explaining why you need to shoot crocodiles from a boat. There’s not enough vantage points along riverbanks to get the shots and compositions you need.

And here’s a shot of the other members of the team, with a bonus crocodile in the left background [:)]





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