The Butterfly of Doom: Everything connected?

It is a banality of the ecological sciences to state that everything is connected. That ebullient Scot, and eventual stalwart of the American wilderness movement, John Muir, claimed, "When we try to pick out anything by itself, we find it hitched to everything else in the universe." And if such statements are employed to sponsor a notion that individual organisms cannot be regarded in isolation from those that they consume, and those that can consume them, or furthermore, that as a consequence of the deep intersections of the living and the never-alive, that there can been unforeseen consequences flowing from species additions or removals from ecosystems, then few may argue with this. However, just as the ripples of a stone dropped in a still pond propagate successfully only to its edges (though they may entrain delightful patterns in the finest of its marginal sands), not every ecological event has intolerably large costs to exact. True, if the dominoes line-up and the circumstances are just so, a butterfly’s wing beat over the Pacific may hurl a typhoon against its shores, but more often than not such lepidopterous catastrophes do not come to pass. Ecosystems, energized so that matter cycles and conjoins the living with the dead, have their lines of demarcation, borders defined by their internal interactions being more powerful than their external ones.  They are therefore buffered against many potentially contagious disasters.  This, of course, is the essence of resilience - the capacity of a system to absorb disturbance without disruption to habitual structure and function.  Ecology is as much the science investigating the limits of connections as it is the thought that everything is connected.

Two Blind Watchmakers and their Thermodynamic Braille – Why Living Systems are Hierarchical

In a post earlier this week I retold the story of Genesis, giving it a systems theory spin. In that story I emphasized God’s role as creative disrupter. The story was a stretch perhaps; it was the best I could write on a hot Chicago day after 24 hours without electricity! A more deftly-told story related by systems theorists conveys other important aspects of the systems message. It goes like this.

Once upon a time there were two watchmakers. The watches that they craft are each composed of one thousand pieces. Now, one of the watchmakers, a systems thinker seemingly, proceeds by assembling subunits of hundred component parts; these subunits when complete are stable. They can then be set aside before finally all completed ten subunits are assembled into the final product. The other watchmaker assembles each watch in its entirety after which that watch is complete and stable. Both watches are functionally indistinguishable. Since the watches are intricately made and take a considerable amount of time to assemble, each maker will get called away from their labour with some frequency. If the first watchmaker gets called away before a watch is fully assembled, the subunit that the she is working on falls apart but the already assembled subunits remain intact. Upon her return, the task is resumed with little loss of work. Her colleague’s efforts, however, decompose to hundreds of scattered pieces when she is disrupted and upon return the work must start from scratch.

The point of the story is somewhat obvious: we live in a conspicuously hierarchical world where many, though not of course all, of the objects of concern to us are composed of parts within parts (like Chinese boxes, as systems theorists like to say), akin in some respects to the watch assembled by the first of our watchmakers. Why is this the case?

Introducing the Rules of the Ecological Game: The descent of a flock of hierarchy theories in Manhattan, circa 1986

TAKE HEED YE YOUTHFUL SCHOLARS: books discovered in your tender years will influence your thinking for decades to come. In 1987 while surfing the stacks of the library of CUNY Graduate School in Manhattan, I plucked off the shelves a copy of Hierarchy: Perspectives for Ecological Complexity by T. F. H. Allen and Thomas Starr (1982). Shortly after this I picked up a copy of a monograph by R.V O’Neill and his colleagues (including T.F.H. Allen) entitled A Hierarchical Concept of Ecosystems. I recall that this volume was regarded with a measure of scorn, albeit a bemused rather than a vicious scorn, by several of the ecologists who taught me at the time (primarily population and community ecologists). It was this book, placing the ecosystem into the framework of a more general systems theory, that ultimately had the longest lasting influence on me in terms of my conception of how the complexities of nature can be made tractable. 

Hierarchy theory was in the air back them. Perhaps one should say “hierarchy theories” since the observation that many of the complexities in the world can be resolved into structures comprised of parts within parts within wholes is not only a commonplace observation; it is one that has been theorized in many disciplines. Herbert Simon, a leading figure in developing this perspective, was an economist, Ilya Progogine, a chemist, Howard Pattee, a theoretical biologist, Jean Piaget a developmental psychologist. Hierarchy theory draws upon more general systems theory developed by luminaries such as Ludwig von Bertalanffy and James Grier Miller, both theoretical biologists. These early students of complex systems developed ways of thinking about commonalities between disciplines whose objects were structured as nested sets of parts within wholes (in more mathematical terms, hierarchies are a partially ordered set).

From the universe as a whole down to the atoms: distinctions between community and ecosystem ecology

Tools of the trade: ecosystem ecology

In one of the more nerve-wracking moments of my early career I was informed that the ecosystem concept was “putting food on the family table.”  I was to stick to the methods of ecosystem ecology and not to waste time with community level questions.  By this I understood that I should not indulge an interest in individual organisms nor attempt to identify these to the species level – certainly this was consuming a lot of my time. I should not, I was told, become overly interested in species diversity, another community-level phenomenon.  Though ecology is rapidly changing, nevertheless as recently as a decade and a half ago you picked your favourite flavour early – if you chose chocolate it is frowned on if you started adding dollops of vanilla.

The ecosystem, as we have discussed, is a compound constituted by all the organisms of a region interacting with the non-living environment – soil, water, and atmosphere.  In modern ecology the ecosystem concept has become the foundation for functional studies of the environment, often at the landscape scale, where ecologists study the processes contributing to the flow of energy (primarily starting with the photosynthetic “fixing” of the sun’s energy by plants) and the cycling of nutrients.  For instance, a present-day ecosystem ecologist might be interested in how the rates of leaf litter decomposition in a woodland affects the availability of nutrients in the soil, thus influencing subsequent plant growth.  This functional interpretation of the ecosystem is contrasted with the approach taken by population and community ecologists who study the interaction of individual organisms, the growth of populations and the interactions that occur between individual of multiple species coexisting in the same place at the same time.