Clade-specific consequences of climate change to amphibians in Atlantic Forest protected areas

Loyola et al. Ecography 36: 1-8. DOI:10.1111/j.1600-0587.2013.00396.x. Clade-specific consequences of climate change to amphibians in Atlantic Forest protected areas

amphibians_brasil

Amphibian species recent now (left) and 2080 (right). A message… from the future! From Loyola et al.


Will Pearse

Will Pearse

Lynsey gave me a wide selection of papers this week, and I picked this one because I’m thinking a lot of about the phylogenetic structure of ecological communities and biogeography. The authors predict amphibians’ distirbutions in Brasil in 2080 on the basis of their present distributions, and then examine the implications for protected areas.

I found this paper quite hard to interpret, and I’d appreciate your input! I found figure 2c, which shows phylogenetic diversity in protected areas now and in 2080, hard to read, as did the authors: “phylogenetic diversity increased under future climatic conditions, albeit such increase was not clear (Fig. 2C)”. The magnitude of the change (0.04 is the biggest I could see) seems very small, but it looks to me like those areas with the greatest diversity now have lesser diversity in 2080, and vice-versa, so could there be some kind of interaction going on? I’d love to write about the within-clade results, but I simply don’t understand figure 3 where they’re presented. The authors seem to have made a matrix that represents clade composition in the protected areas, and then plot principal components of that matrix, but figure 3 shows present and future climatic conditions plotted on the same axes as monophyletic clades, and I don’t know how that’s possible. Help!

However, the general approach of examining variation in response among clades is interesting. I think making predictions about protected areas’ future phylogenetic diversity is particularly useful if we want to understand ecosystem function, and I think approaches like these have the potential to be of conservation importance.


Lynsey McInnes

Lynsey McInnes

Ouf, this was a strange paper. I do think the premise was well-intentioned, but the execution was really quite confusing. As I understand it, the authors were interested in seeing how climate change will affect amphibian richness, diversity and phylogenetic diversity in protected areas within the Atlantic Forest of Brazil. A fair enough intention, protected areas are, debatably, the best hope for the persistence of endangered species, and amphibians, more so than other vertebrate groups are undoubtedly endangered. Furthermore, it is of interest whether protected areas protect certain amphibian species better than others, so the phylogenetic perspective could be a valid and important one in order to predict what kinds of amphibians we will be left with in the future.

But this is kind of where I lost the plot. I really struggled with the authors’ approach to defining phylogenetic diversity and similar to Will struggled to interpret figure 3. I also thought they altered between considering the traits of vulnerable species vs. their basal vs. derived status in the phylogeny. Phylogenetic diversity and its maintenance is of interest, but ultimately, I’m more interested in maintaining a diverse amphibian fauna (and I think the authors are too) so they could have devoted more discussion to the traits that help amphibians persist in warmer, drier areas. They highlight that the increase in phylogenetic diversity that they predict should be interpreted with caution given that it comes hand in hand with a decrease in species richness and the paper could have used this interesting result as a springboard into a more philosophical discussion of whether or not this is an acceptable tradeoff.

The authors are also admirably open as to the deficiencies in the methods they employ, namely that their species’ distribution models do not incorporate realistic dispersal parameters or the effects of sustained or disrupted biotic interactions. These problems plague many similar studies and it seems like the field is changing so fast that soon these omissions might make publishingsuch studies harder and harder. On the one hand, this is good, we should as a research community be tough on ourselves, and on the other, is a shame, as this study, even with its flaws and difficulties, can provoke valid discussion on how to go about conservation with limited funds.

One last grumble, I am deeply sceptical on ensemble forecasting. My understanding is, all models are quite uncertain so we should take an average of all such uncertain models and this will give us an average model with much LESS uncertainty? Hm.

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About will.pearse
Ecology / evolutionary biologist

2 Responses to Clade-specific consequences of climate change to amphibians in Atlantic Forest protected areas

  1. Comment: “I found figure 2c, which shows phylogenetic diversity in protected areas now and in 2080, hard to read,”

    Reply: I’d like to hear more about it, but it basically shows that on average there will be an increase in the Rao quadratic entropy by 2080.

    Comment: The magnitude of the change (0.04 is the biggest I could see) seems very small, but it looks to me like those areas with the greatest diversity now have lesser diversity in 2080, and vice-versa, so could there be some kind of interaction going on?

    Reply: We actually tried to include several facets of biodiverity in our analyses. There could be interactions of course, but the increase in phylodiversity is due most probably to the shift in the range of more basal clades within Anura (e.g., Pipidae) and Gymnophiona, which makes genera from those clades present in Protected Areas by 2080 in which thy were not present currently.

    Comment: I’d love to write about the within-clade results, but I simply don’t understand figure 3 where they’re presented. The authors seem to have made a matrix that represents clade composition in the protected areas, and then plot principal components of that matrix, but figure 3 shows present and future climatic conditions plotted on the same axes as monophyletic clades, and I don’t know how that’s possible. Help!

    Reply: Some people pointed out the same, I think it’s hard to understand it because we didn’t spend to much time explaining how to compute the Principal Coordenates of Phylogenetic Structure (PCPS). You can get a better coverage on this topic on these papers: http://goo.gl/HDIlrW, http://goo.gl/F6GIJU, http://goo.gl/pE3qUp . To get a better understanding of Fig. 3 you should also contrast it with both Table 1, in which we show the relationship between the PCPS axes and climate change, and the supplementary material. We actually removed a figure that showed the percentage of range reduction of each family, which is a summary of the suppl. data, but it’s available in our poster presented at this year ESA (http://goo.gl/6tZ5QD).

    Comment: Ouf, this was a strange paper.

    Reply: But we are nice people, I swear! 😀

    • will.pearse says:

      We’re nice people too :p July seems like a very long time ago now, but I’ll try and remember what I was thinking at the time…

      I think figure 2 was difficult to interpret because of the plotting; I found it hard to see each individual point and each line linking each point. However, it looks (in 2c) like some of the lines are going upward, not downward, which I guess is what got me wondering about interactions.

      I’ve had a quick skim of those papers (some of which I have read and enjoyed before), and so I think I’m feeling a bit more aware of what’s going on… I think when I looked at figure 3 before I mis-read it as each black circle corresponding to a clade, which is not what’s going on – each black circle corresponds to a species, and you’ve labelled on the plot the clade names those species belong to. So can I read from this that, in the future, the Gymnophiona and Hemiphphractidae will do well, whereas the Bufonidae (and others) are more associated with present-day assemblages? If so, thank you, because I get it now! 😀

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