Category Archives: Ecology

Scepticism towards the Living Planet Index is unwarranted

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The most recent Living Planet Report was released last year, which showed that vertebrate populations around the world have declined by 68% on average. At the time, Brian McGill wrote a post at Dynamic Ecology expressing his scepticism over these large declines. His doubts stemmed from several related papers, which all showed that vertebrate populations tended to be quite stable on average. While some populations have declined, most have remained stable and others have actually increased.

My understanding of Brian’s message (and the messages of the published papers supporting him) was that while humans do affect vertebrate populations, these effects are not consistently negative. Instead, some species benefit from human actions, so human’s ultimate legacy will be rearranging relative population structure, rather than causing wholesale declines.

While I agree with this interpretation, I worry that it is causing unwarranted mistrust of the Living Planet Index. I was reminded of this last week by a passing comment by Mark Vellend:

“If biodiversity seems intractable, then just think about recent discussions of the Living Planet Index, which is based on pretty simple underlying data.”

His remark was in the context of his post suggesting that ecologists have subconscious biases that cause us to exaggerate how much humans harm biodiversity. Ecologists probably do have subconscious biases, but the Living Planet index shouldn’t be used as evidence of this.

I don’t believe the Living Planet Index exaggerates population declines. However, I also recognise that populations are stable on average. This probably seems contradictory, so I’ll use the rest of this post to explain why it isn’t.

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Scientific journals should be judged, not ranked

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Aspiring scientists quickly learn that where they publish their hard earned data is important for career progression. A paper in a prestigious journal pushes them up the professional ladder faster than the same paper in an obscure one.

This has led to an obsession with quantifying the prestige of a journal using impact metrics. Over at Conservation Bytes, Corey Bradshaw presents a RShiny App to rank ecology and conservation journals using a composite of different citation metrics. His app is based on a published paper, so you can be sure that it technically sound. It is not my intention to criticise these efforts; if you want to rank jounals, then this composite approach is definitely the way to go.

However, I don’t think there is much to gain from ranking journals based on their impact metrics. Moreover, scientists – especially early-career scientists – would be better off judging journals based on whether is will ensure that their paper reaches the right audience.

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Trump’s Wall could affect 350 species of amphibians, reptiles and mammals

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I originally started writing this post two years ago, back when Donald Trump had just been elected as President of the USA. I didn’t finished writing it then because I assumed that the topic was just a passing fad, something none of us actually took seriously. Fast-forward to today, the US government has been shut down for more than three weeks as Trump tries to hold the country hostage over his border wall with Mexico. I suppose now is a as good a time to finally publish this post, even though a paper was published on the topic in BioScience last year.

As one of the most absurd campaign promises in recent history, Donald Trump’s commitment to building a wall between the United State and Mexico has attracted many critics. Many scoffed at his claims that such a structure will keep out the make-believe mob of bad hombres chomping at the bit to sell drugs to innocent Americans. Others giggled at Trump’s conviction that those very same bad hombres would pay for his trademark erection.

But this post is not about the fragile justification for building a massive wall. It’s a thought experiment on how many species would be affected by this cross-continent barrier.

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How do correlations between climate and biodiversity arise? UPDATED

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Anyone who as ever watched a David Attenborough documentary knows that biodiversity differs in areas with different climates. Only a few species an survive in hot and dry deserts whereas warm and wet tropical forests are teeming with life. But have you every stopped to wonder why this is so?

Why are certain climate conditions able to support many species and others not? More specifically, how does this work mechanistically?

This was the question my co-authors and I set out to answer in our most recent paper just published online at Global Ecology and Biogeography.

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What can Sudoku teach us about ecology and evolution?

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Evolution is creeping into several different aspects of ecology. The latest buzz is all about integrating ecology and evolution. Perhaps you’ve heard of the  latest research trends in eco-evolutionary dynamics or community phylogenetics?

Theodosius Dobzhansky famously stated that “Nothing in biology makes sense except in the light of evolution“. This claim is undoubtedly true, but I’ve recently found myself wondering whether our obsession with evolution is actually clouding our ability to do good ecological research.

Please don’t misunderstand me, I am not implying that evolution is not important in explaining patterns in nature, nor am I suggesting that we should disregard evolutionary explanations for these patterns. Instead, I believe that in order to gain a deeper understanding of ecology, we should perhaps partially blind our views using “evolution blinkers”. In fact, I’d even be so bold as to claim that unless we blind ourselves to evolution, we will never be able to fully grasp the true nature of ecological processes. Unifying ecology and evolution might actual limit our ability to build ecology as a science.

Richard Feynman used a useful chess analogy to explain how physics works. I’ll borrow this style of argument to explain my stance on ecology and evolution. However, since chess is too complicated for my liking, I’ll use an even simpler game: Sudoku. Continue reading →