If you’re reading this, then it’s safe to assume that you love nature. Your passion for all creatures great and small might even have pushed you to pursue a career in ecology or conservation biology. But is passion enough?

I don’t think so, and here’s why.

Let’s imagine a scenario where there are 150 possible conservation programs that can be implemented by a conservation agency. Each has a fixed cost randomly selected from a normal distribution (mean = $ 5 000; standard deviation = $ 1 500) and a fixed conservation benefit, also from a normal distribution (mean = 70; standard deviation = 15). The benefits are arbitrary units but, if it makes things easier to understand, imagine that it is the number of species protected by the program. The scenario is also set up so that there is a 0.75 correlation between the cost of a program and its benefits: generally, the most expensive programs reap the greatest conservation rewards (although this relationship is not perfect).

It is also worth mentioning that, while these parameters were selected at random, all conclusions are robust irrespective of the choice of parameters.

Now, let’s assume that there are four deputy-directors that can devise a conservation portfolio by investing in the 150 different programs while being limited by a strict budget of $ 200 000.

The first deputy-director is a slightly overweight, easy-going guy named Tony. Tony moved his way up to deputy-direct because he is such a likeable fellow; he is always willing to help, tends to avoid conflict and generally follows the path of least resistance. Tony didn’t really have a strategy to devise his conservation portfolio, so he chose his programs depending on whether they were in nice parts of the country, had program managers he liked or, otherwise, those that crossed his desk first. In short, Tony randomly selected the programs until his budget ran out. (Tony’s selections are marked in BLUE)

The second deputy-director is a sweet-natured, caring woman named Lilly. An ecologist by training, Lilly believes that nature has an intrinsic right to existence. Her belief that nature should be conserved, regardless of the cost, was forged while she volunteered at a monkey sanctuary in Rwanda during here early twenties. As such, Lilly built up her portfolio by selecting the programs that had the highest benefit to nature. (Lilly’s selections are marked in GREEN)

The third deputy-director was a real dullard of a man named Nigel. As a qualified accountant, Nigel always has a calculator stuffed in the front pocket of his favourite beige suit. Despite his inability to hold conversation at dinner parts, he managed to move his way up to deputy-director due to his meticulous book-keeping: his departments never had even a penny that was unaccounted for. Like all the decisions in his life, Nigel built his portfolio by bargain-hunting. He always selected the cheapest programs until his $ 200 000 budget was depleted. (Nigel’s selections are marked in YELLOW)

The last deputy-director is a cut-throat go-getter named Natalie. Natalie finished first at university with a double-major in business management and applied mathematics and she has never, ever suffered the indignity of settling for anything other than the best. She wants the best job, best lifestyle, best home, best children best… you get the picture. Needless to say, Natalie’s inability to tolerate fools meant that she ruffled many feathers on her way to the deputy-director; but her results speak for themselves. Like everything else, Natalie had to optimise her conservation portfolio. She determined the relative benefit of each program and built up here portfolio by selecting the most effective programs per dollar until her budget was exceeded. (Natalie’s selections are marked in RED)

So, how did the team of deputy-directors compare? (To make it fair – and more scientific – I repeated this exercise 1 000 times, just to be sure that there weren’t any quirky numerical artefacts)

Looking at these results, who would you promote to be the next director of the conservation agency? Remember that they all spent the same amount of money: $ 200 000.

Natalie, with her Type A personality, outperformed everyone… In fact, it wasn’t even close. Dreary, number-crunching Nigel got himself second place by always choosing the cheapest option. Lilly, the only ecologist and arguably the only deputy-director with sincere motives driven by environmental consciousness, came dead last! Even Tony, who might just as well have rolled dice to make his decisions, beat her.

Who would you promote to the position of director?

• You could replace Tony with a random number generator (or an intern who can flip a coin). Surely he isn’t the best candidate?
• Lilly’s intentions were pure and she really cares about nature but, let’s face it, her passion blinded her to the financial realities of the modern day conservation world. She’s rather bad at her job.
• Nigel, while actually quite effective, knows absolutely nothing about biodiversity. In fact, his ignorance is only exceeded by his disinterest. Is he the person you want to represent a conservation agency?
• Lastly, there is Natalie. She clearly outperformed all the others. She is undoubtedly a super-star when it comes to her job.

While I wouldn’t go as far as saying that – as was the case with Lilly – passion always undermines the efficacy of conservation efforts, it’s clear that passion alone is not enough to reverse species loss. This is especially true in the real world, which has more economic, social and political intricacies conveniently omitted from my toy model. Conservation is a complex task and it needs people who can appreciate complexity and tolerate ambiguity. It needs strong-willed people who can see the bigger picture and make difficult decisions that, at the surface, seem to go against the grain of traditional environmental ethics.