Chthonic Wildlife Ramblings

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.

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

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.

One of the reasons I enjoyed my expedition to Darwin, is that it gives you a first-hand look at a conservation success story. A number of crocodilians have achieved quite marked recoveries in numbers since the 1970s. One of those successes has been saltwater (or estuarine) crocodiles in Northern Australia. Least we think that this is peculiar to rich, developed countries like Australia, it should be pointed out that Papua New Guinea has had similar success.

Saltwater Crocodile- Crocodylus Park


So, what were some of the drivers behind the success here?

First, it had a lot to do with crocodile conservationists recognising that they were faced with a moving target. The problems facing crocodiles would always be changing. They'd also be changing in ways that would be near impossible to predict. So the ideal was to have a fast-adapting management system. The flip was to avoid locking-in the same strategy. There seems to be a view by many conservationists that to protect wildlife, you devise the appropriate strategy and lock-it in. Whatever happens, you keep using that same strategy. This is the logic that almost brought about the extinction of the Californian Condor.

So, rather than sticking to the same strategy that worked when crocodiles were rare (protection, no-trade), the goal was to move to a new strategy that would work with growing abundance. That meant considering sustainable-use.

The second factor is allied to the first. This is the concept that conservation is a discovery process. It's not a prescriptive process whereby you set out and plan what you will do before acting. It's a process where you try to learn the best way to do things as you do it- you test boundaries, see what happens if something changes etc. For example, the first egg harvests were very simple. Collect all the eggs you could find along a river and see what happens. There's no elaborate planning and estimation of maximum-sustainable-yields (partly because the reproductive biology of crocodiles was not well understood anyway).

Hence, there was a certain boldness and willing to try out new ideas that influenced the management. There was no timid, don't make a move before we understand everything. This is the sort of thinking that can generate lock-ins of suboptimal strategies.

The third (and final point for this post) is the absence of NGO involvement. These harvest programmes started in the 70s and early 80s. We got lucky on the timing side. Now this may seem a surprising point, but NGOs have grown in number, size and influence throughout the late 80s and 1990s. And a lot of them don't manifest a lot of enthusiasm for sustainable-use. At the moment, we can't get the Australian Federal Government to agree to safari hunting of 25 crocodiles a year in the Northern Territory. The reason lies with NGO opposition, despite this having conservation effects that will be discernible. If we can't get 25 large, nuisance crocs shot by safari hunters, the concept we could harvest thousands of eggs for commercial gain is really not going to fly. Essentially, crocodile conservation in the NT got lucky by sneaking sustainable-use in, before NGOs really started intensive lobbying.

One of the uncertainties of dealing with the media is just how they opt to present your research. The minefield that is tigers can lead in all directions. So far for tigers I've been the 'good guy' in some publications and the 'bad guy' in others. All for mentioning we need to discuss unpalatable options to save tigers.

For the record, most of my research has been on the black market (chiefly in China) in tiger parts. Like everybody else connected with tiger conservation, I don't know exactly what we should do to save wild tiger populations. Anybody who claims to know the answer, probably doesn't understand the problem

So, it was kind of fun reading the piece written by a Massey University journalist. (Also, I'm marking essays and don't really have time to craft a serious blog piece).

Intro
He's the Indiana Jones of the Department of Commerce, or so some say. The similarities between the Hollywood character and the Massey University senior lecturer Dr Brendan Moyle are clear to see. Both university academics by profession- their 'crusades' take them on exciting adventures in far flung destinations in pursuit of the bad guys. But while Jone's role is confined to the silver screen, Moyle's mission to save the tiger species from extinction is very real. It has come with it's own perils as he works covertly in China to try to understand the complex black market in trade of tiger parts...

Wow, that's some introduction. Actually 99% of the time it's pretty boring. This piece is inspired by the say 1% of the time it does get exciting. But that really isn't the norm.(I'm afraid the reporter seemed a little disappointed that my short 'detention' by the Chinese army - in 2008 - didn't involve anything really exciting- like say rubber hoses.)

On the plus side, it does emphasise that I'm researching the black market, not tiger farms. And it's clear I use a hands-on approach, rather than hide behind a keyboard. Sad to say though, a modern academic is increasingly unlikely to live a life resembling that of Indiana Jones.

Later on, the conclusion:

So, are you Massey University's answer to Indiana Jones?

If I am Indiana Jones, then I'm Indy with more mud and meetings* and less gunfire - I'm also not afraid of snakes

* Real academics know what I mean about the meetings. In that respect, I wish I was more like Indiana Jones