Category: GIS

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Mapping Species Distributions previewed

Dag Endresen introduces Mapping Species Distributions by Janet Franklin, just published by Cambridge University Press.

Species Distribution Modeling (SDM) has really found its way into the scientific literature of late. It has moved from its origin in ecology, to a wider use in life sciences, including also recently data analysis in agriculture. Andy Jarvis, for one, has recently done some excellent studies of crop diversity with MaxEnt. I have not yet read this book, but have ordered it from my favorite online bookshop. Here’s why.

The book introduces the theory and the fundamentals of SDM and proceeds with a deeper description of the many different data analysis methods that has been applied. The list of methods is long (and still growing). However, it seems this book gives comprehensive guidelines for selecting the appropriate method for your own SDM study. I believe that Janet Franklin, the author, teaches species distribution modeling with the free open source R statistical analysis software. We can perhaps hope to find also some few examples of how to apply the described methods with the R package.

The books seems, however, much more focused on the understanding of the ecological principles for SDM and species-environment relationships. The large section on the SDM methods aims to provide us with an understanding of the assumptions and limitations for the models and predictions. I hope this will help to relieve the kind of “black-box” mystery I sometimes feel for many of the SDM methods. We shall see.

Janet Franklin has long experience of biogeography, with appointments as professor of both Geography and Biology.

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Nary a drop to drink

The BBC had an interesting series of maps in December last year on the effects of climate change, economic and population growth on per-capita water availability, based on the work of Martina Floerke and colleagues at the University of Kassel in Germany. Here’s the picture for 1961-90. Red is bad.

1961

And here is the 2070s. Click to enlarge.

2070s

Doesn’t look good, particularly for Central and West Asia, and both southern and North Africa. That’s where your drought tolerant crop varieties are going to come in useful, I guess. And not just that. But I don’t understand how Australia gets away with it so lightly.

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How fast will this climate change be anyway?

ResearchBlogging.orgWell, in terms of distance along the Earth’s surface, about 400 m per year on average, ranging from 80 m per year in mountainous regions to 1.26 km per year in deserts. That’s according to a new paper in Nature by Loarie et al. ((Loarie, S., Duffy, P., Hamilton, H., Asner, G., Field, C., & Ackerly, D. (2009). The velocity of climate change Nature, 462 (7276), 1052-1055 DOI: 10.1038/nature08649)) Compare that with figures of postglacial migration rates of <100 m per year for some trees. Here’s a map of the speed of temperature change by biome from the Nature paper (click to enlarge).

map

And here’s the “persistence time” for protected areas in different biomes, i.e. the diameter of protected areas divided by the climate velocity.

persistence

The persistence time — which is how long it takes for the current climate to cross a protected area — exceeds 100 years for only about 8% of protected areas. And that, dear reader, is why we need protected areas that are larger and more connected. Oh, and genebanks.

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Re-inventing the genebank. Not.

ResearchBlogging.orgJeffrey Walck and Kingsley Dixon ((Who are respectively at the Department of Biology, Middle Tennessee State University, Murfreesboro, Tennessee and at the School of Plant Biology, University of Western Australia, West Perth.)) have a piece on genebanks in December’s Nature entitled “Time to future-proof plants in storage.” ((Walck, J., & Dixon, K. (2009). Time to future-proof plants in storage Nature, 462 (7274), 721-721 DOI: 10.1038/462721a)) It says some important things, but in a way that suggests that nobody has thought of them before, or has done anything about it, which I think needs to be countered. ((I wont say anything here about the lumping together of the Millennium Seed Bank at Kew and the Svalbard Global Seed Vault, which is just plain silly.)) The article is behind a paywall, alas.

Here’s the crux of Walck and Dixon’s beef.

At low temperatures, seeds can remain viable for hundreds if not thousands of years. Herein lies the problem: such seeds are literally frozen in time, a snapshot of the genetic diversity of a species at a particular point. Attempts to revive a seed in future habitats very different from those in which it developed could be doomed to failure. A germinating seed is genetically programmed to respond to a precise interplay of temperature and moisture that determines the climatic conditions in which it can best develop. In an environment that lacks the right temperature and moisture balance — which is likely to be disrupted by climate change — a seed will either fail to germinate or the seedling will perish soon afterwards (see Fig. 1).

What are their suggestions for getting around this problem? Here’s a summary:

    1. Harvest as much genetic diversity as possible, including at the edge of species ranges, and at different points in time. And harvest large quantities of seed whenever possible.
    2. Screen the plants for their adaptation to different environments. “For instance, subjecting seedlings to increased temperatures could allow the selection of those with higher heat tolerance.”
    3. Use climate models to identify areas where different populations will be best adapted. “…climate change will alter the home range of a species, so restorers can be sure to reintroduce seeds in places that will match their particular germination requirements.”
    4. “Policy-makers must get involved too: a comprehensive international agreement is required to coordinate the collection of genetic material, particularly for cross-border wild species.”

So, that would be collect properly, evaluate, match seeds to environments and put in place an international policy infrastructure. Doh! I really can’t see anything in that list that genebanks are not already trying to do. Can you? Maybe they’re not doing it as well as they might, and certainly the policy environment is still not ideal, but there’s surely nothing particularly new about these recommendations. Sure, it is always useful to remind a community about best practices, but it would have been nice to point out that genebank managers around the world know what these are, and are in fact trying to follow them.

If they had wanted to suggest something that isn’t already in place, why didn’t they mention the pressing need for a comprehensive global information system? Now that would be an improvement. And yes, we — and they — are working on it.