Sybille Haeussler

Hello everyone. I'm very excited to be going to Beijing and looking forward to meeting you. I am a post-doctoral fellow in forest ecology at the University of British Columbia, Canada. Here are two weblinks that tell you something about me: [1] [2]

Five Questions:

1. What topics do you have some expertise in and would you be willing to help others learn them? I am very experienced as a field ecologist in terrestrial systems and know a lot about vegetation, soils, and ecosystem dynamics across scales. I also have a good background in old-fashioned frequentist and multivariate statistics, and experimental design. Another area where I have expertise is in multi-stakeholder consensus-based, decision-making bodies, so I understand the dynamics of problem-solving in groups with varied backgrounds and interests.

2. What do you want to learn at the CSSS? I want to get a solid grounding in complex systems theory and gain hands-on experience in modelling complex systems. I also want to meet and work with interdisciplinary groups on big picture, real world problems. By the end of the course I would like to be able to write a research proposal to fund my work on ecosystem diversity (see below) and it would be a real bonus to meet some potential collaborators.

3. Do you have any projects or research interests that would benefit from an interdisciplinary approach? Absolutely. One of my research projects is a model of terrestrial ecosystem diversity in changing environments that is based on notions of self-organized criticality. In developing the conceptual basis for the model I borrowed heavily from genetics, physics and geology. I'm hoping to start building a functioning simulation model but need help from others with more advanced computational and computer skills.

I am also involved in a non-profit research institute whose goal is to increase socio-ecological resilience in small resource-dependent communities of northern British Columbia. The forests upon which our economy has been based for the past 50 years are dying from a massive insect outbreak (the mountain pine beetle). We can use all the interdisciplinary help we can get.

4. Do you have any ideas for what sort of project you would like to do this summer? I’d be very happy to work with others on projects unrelated to my own field of research, but here are two project ideas I came up with:

a) A scaling law for terrestrial ecosystems: One of the barriers to developing a robust theory of ecosystems that can guide the conservation of ecological diversity is that an ecosystem can range in size from smaller than a drop of water to the size of the whole planet (Gaia). It would be great if there was a natural scaling law analogous to the body size law for vertebrates. This photo from northern BC (I hope it isn't too small to see) shows a clear pattern of increasing scale of vegetation/soil units from mountain top to valley floor. Two alternative hypotheses for the pattern are:(1) the scaling of vegetation/soil units is a function of the height of the vegetation and the depth of soil profile development; (2) the scaling of vegetation/soil units results from the dendritic pattern of water flow down the mountain slope (water droplets on the rock in the foreground coalesce to form major rivers by sea level).

b) Is repression in lodgepole pine stands an emergent process? I’m having trouble understanding the concept of emergent processes. On the one hand, there are phenomena that arise as a non-linear consequence of (or collective response to) individual behaviours we already know something about. I can imagine how that might work in an agent-based model. But what if the collective behaviour is something that truly can't be predicted from lower level behaviour? How is it possible to model that? Does one dream up mathematical formulae for potential interactions among agents without worrying about the underlying mechanics?

Here is a simple example from forestry: Forest trees growing in uniform, dense stands, normally develop competitive hierarchies in which the larger trees become progressively more dominant while the smallest die out through a process known as self-thinning. Lodgepole pine is a species that grows in dense single-species stands after wildfire and doesn’t self-thin as readily as other species. Above a certain threshold density, a surprising phenomenon “emerges” in which no competitive hierarchy develops and all of the trees remain stunted and small[3]. I'm wonder if this “repression” (a) can be modelled from individual behaviours that we already understand - increasing competition and reduced ability to form competitive hierarchies in extremely dense stands; or (b) whether it is truly an emergent process in which the dense pine community starts to behave as a supra-organism with sychronized physiology – analogous to young women in university residences who begin to synchronize their menstrual cycles. We can test for (a) by tweaking the parameters of an existing individual tree growth model (ie, agent-based model) such as SORTIE-ND[4]. I have no idea (yet) how to model (b) other than to invent an interaction for which we currently have no empirical evidence. I suppose if (b) is the only way to reproduce the collective behaviour then the next step would be to design an experiment that tests for the interaction that produced the response in the model.(???)

5. Suppose you could travel one-hundred years in the future and ask researchers any three questions. What would those questions be?

a) Where does consciousness come from and where does it go after death?

b) What is the size of the human population? Have humans been able to develop sustainable economies built upon some premise other than continous growth and increasing per capita consumption?

c) Are humans still the dominant lifeform on earth or is artificial life (computers) now in control?

Sybille