MODSIM Conference, Day 1

I am attending the MODSIM International Congress on Modelling and Simulation in Hobart, Tasmania. It promises to be another great event.

I spoke today on “Sampling bias and implicit knowledge in ecological niche modelling.” Out of the many interesting talks I listened to, one that stands out is “The Waroona fire: extreme fire behaviour and simulations with a coupled fire-atmosphere model” by Mika Peace. It introduced me to “pyrocumulonimbus clouds,” and some of the complex weather–fire interactions in severe bushfires. This is certainly a phenomenon that needs to be better understood.


Ecological literacy and Frank Herbert’s Dune, half a century on

Dune by Frank Herbert

The year 1965 saw the appearance of what has been called “the first planetary ecology novel on a grand scale.” Frank Herbert’s Dune explored a plethora of interesting themes, notably that of ecology. The novel speaks of “… teaching [the children] ecological literacy, creating a new language with symbols that arm the mind to manipulate an entire landscape, its climate, seasonal limits, and finally to break through all ideas of force into the dazzling awareness of order.

The use of food webs, like the one for waterbirds of Chesapeake Bay above, was fairly standard by 1965, and Herbert seems to be hinting at a graphical language for ecology going beyond that. Exactly what he was referring to is unclear.

But are we teaching the kind of ecological literacy Herbert refers to? A 2013 survey indicated that, out of 145 US tertiary institutions ranked for “Ecology and Evolutionary Biology” and “Integrative Biology,” only 47% taught a course in ecosystem ecology or biogeochemistry, and only 22% of the courses included field experiences. A 1993 survey of UK secondary teaching (A-levels and GCSE) showed that students only studied a median of 2 or 3 different habitats:

So how many children actually understand, say, trophic cascades in the wolf–elk ecosystem? How many adults, for that matter? The evidence suggests that it’s not very many, judging by the resistance to sensible management of National Parks. If we do not wish to recreate the desert planet Arrakis, we might like to work on that.

Ecological networks and the Australian dingo

I’m excited at the publication of a joint paper on network ecology, with a focus on the Australian dingo: “Trophic cascades in 3D: Network analysis reveals how apex predators structure ecosystems” (by Arian D. Wallach, Anthony H. Dekker, Miguel Lurgi, Jose M. Montoya, Damien A. Fordham & Euan G. Ritchie, and appearing in Methods in Ecology and Evolution).

Associated with this publication is an animation I put together for the paper showing how the ecological network changes if the role of the dingo as apex predator is weakened. I’m grateful to my ecologist co-authors at the opportunity to contribute my mathematical skills to such an interesting project.

The Blue Mountains Water Skink

The endangered Blue Mountains Water Skink, Eulamprus leuraensis (photo: “Sarshag7”)

I have previously mentioned my interest in ecological niche modelling and amphibians. The cute little skink above, native to the Blue Mountains near Sydney, is sadly endangered. The black circles in the map below show online occurrence records for the skink. These range in altitude from approximately 530 to 1,170 m.

The blue area shows a predicted potential range for the species, based on MaxEnt modelling using those occurrence records and BioClim climate data. The model does not take into account the skink’s need for sedge and shrub swamps with permanently wet boggy soils – there are readily available online land cover datasets, but these have insufficient spatial resolution to identify the 30 or so swamps in which the skink is found. The predicted potential range for the skink is consequently very much exaggerated, and covers 1,320 sq km, of which 63% falls within national parks or other protected areas. Hopefully that is enough to stop this beautiful amphibian from becoming extinct, although it continues to face threats from urban sprawl, feral cats, and vegetation changes.

Ecological Niche Modelling and Frogs

Predicted suitable range (in blue) of frogs from the Leptolalax applebyi group in Vietnam, Cambodia, and Laos (modified from Rowley et al. 2015). The vertical colour scale shows elevation in metres. Frog images are by Jodi Rowley.

I was very excited to have the opportunity to collaborate recently with AMRI at the Australian Museum on a paper about frogs, which has just appeared in PLOS ONE: Undiagnosed Cryptic Diversity in Small, Microendemic Frogs (Leptolalax) from the Central Highlands of Vietnam (Jodi J. L. Rowley, Dao T. A. Tran, Greta J. Frankham, Anthony H. Dekker, Duong T. T. Le, Truong Q. Nguyen, Vinh Q. Dau, Huy D. Hoang). My main contribution to the work was in ecological niche modelling – see the map above.

The Leptolalax applebyi group discussed in the paper hides a number of similar-looking but distinct species of frogs, often restricted to small geographic areas (DNA and acoustic evidence can be used to distinguish them). Ecological niche modelling using climatic and terrain data produced the above map of areas predicted to be suitable for these frogs. Unfortunately, as of a 2008 satellite study, only 55% of this suitable area (in blue on the map) was covered by the broadleaf evergreen forest which these frogs need. The resultant habitat loss may therefore have already led to the extinction of frog species which we will never know about. Less than a third of the remaining area has government protection, so further habitat loss is, sadly, a strong possibility.

The example of the Leptolalax applebyi group underscores the need both to strengthen conservation efforts around the world, and to put more effort into describing the world’s species diversity, so that we know what needs protecting! Losing a species (like the passenger pigeon or the gastric-brooding frog) is tragic, but sadder still is losing species without even realising that they existed.

Some beautiful photographs

Today, some pretty pictures from recent photographic competitions. First, the European Geosciences Union Photo Contest 2014. “Erosion Spider” by John Clemens was one of the winning entries:

Second, the BioMedCentral Ecology Image Competition. “A sticky snack for mice” by Petra Wester was the overall winner:

Finally, the Neuro Bureau Brain Art Competition 2014. “Heart of the Brain” by Chris Steele (MPI Leipzig) won the Best Visualization of Probabilistic Connectivity category:

All images used under Creative Commons license (CC BY-NC-ND, CC BY, and CC BY-NC-SA respectively). Click images to zoom and/or read more about the photographs.

Best Scientific Visualizations of 2013

Wired is listing their “Best Scientific Visualizations of 2013.”

Included on their list is the interesting network diagram below, from the paper “Parasites Affect Food Web Structure Primarily through Increased Diversity and Complexity” by Jennifer Dunne et al. (PLoS Biology, Vol. 11, No. 6, June 2013) – a paper which I have previously mentioned.