Friday Linkfest: Vagueness in ecology, and was I wrong about tropical forest recovery?

Those of you who read my latest post on defining resilience will know I just spent two days discussing what resilience is. It is somewhat ironic, then, that over on Dynamic Ecology on Jeremy Fox just put up a blog post discussing situations when vagueness in ecology can be useful. Considering that he has previously been a stickler for precision he is very open to vagueness, but only when it is productive. For example the concepts of ‘species,’ ‘ecosystem’ and, even ‘ecology’ are fairly vaguely defined – but very few people would argue that they aren’t useful…

Thompson-Reuters have just released their Impact Factors for the year. Exciting, right?  Methods in Ecology and Evolution have moved up to be the 9th highest ranked journal in ecology, and have a blog post about this. Worth reading if only for Bob O’Hara’s recognition that the whole system is a bit ridiculous.

A really nice looking new paper out this week shows that animals with bigger prey, that forage in three dimension tend to have bigger home ranges. Not usually my topic, but I was blown away by how good the figures looked in this paper.

In case you missed it, our paper on the response of different functional groups to forest recovery just came out a week or two ago, you can read a blog post on it here and see the open-access paper here.

For those of you into r and stats, here is a nice ggplot2 cheat sheet that is easily searchable (HT Dynamic Ecology).

A paper that challenges the conclusions of some of my work on forest regeneration has just come out in PNAS. The paper suggests that the characteristics of tropical forests recovering from clearance are highly idiosyncratic. One of our previous studies suggested that these recovery trajectories are relatively predictable, but I am open to the possibility we were wrong. I think this is one paper I need to have a proper read of and write a full post about…

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When is a trait not a trait?

Last week I was on a course on using traits for ecological analysis in Coimbra. Verdict: Unimpressed by the course, but impressed by the beauty of the city.

But I digress.

One of the things that kept coming up on the course was what people considered a to be a trait.

Apparently the strict definition that the people running the course was something along the lines of “morpho-physio-phenological traits which impact fitness indirectly via their effects on growth, reproduction and survival, the three components of individual performance” taken from Violle et al 2007.

I agree roughly with this definition.

But there were a few naysayers in our group. Some of them argued that distribution size was a trait or that habitat that a species preferred was a trait. Personally I think these two things are the result of a trait-environment interaction, and are not themselves traits. However,even papers in the Holy Grail of publications, Nature, can get this wrong so I can understand the confusion.

Certain traits may be increase the likelihood of a species found in a region to be found at a particular site
Certain traits may be increase the likelihood of a species found in a region (left) to be found at a particular site (right)

For example, take a regional species pool that is made up of species that vary in traits which impact their fitness. These traits can determine whether a species is present at a particular site.

Trait_filtering 02
Some species may only be found in particular habitats (green patches) and vary in range size compared to others (black line) but we shouldn’t call these traits.

 

If you add up all the areas that a species is present in you have an idea of a species range and also the habitats they occupy. Therefore it is fairly obvious that these two things are not traits but are rather the products of traits.

This is not to say they aren’t useful in some way. Range size (or more accurately area of occupancy or extent of occurrence) is fundamental to one of conservation biology’s flagship projects – the Red List, and knowing the habitats a species uses can be useful in lots of ways.

It would be helpful if we could all agree what we were talking about when it come to traits, as very few of us seem to have thought about it. When people review a paper that uses the word ‘trait’ they should make sure that the term has some meaning and isn’t just used as a sexier synonym for ‘characteristic’ or ‘feature.’

Ecology is fraught with problems of definition (as I have discussed here and here) and personally I think it is one of the things that holds back our science. If our aim is to form meaningful generalisations about how the natural world works, we can’t do it until we agree what the hell we’re talking about in the first place.