Terrestrial Ecosystem Ecology

agren

Rating: ★★★½☆

Gören I Ågren and Folke O Andersson. 2012. Terrestrial Ecosystem Ecology. Cambridge University Press. ISBN 978 1 107 64825 8.

Perhaps the first thought on seeing this text is why ‘terrestrial’ and not just ecology. That lasts all of a few seconds when dipping into the preface and seeing that the focus is on whole systems i.e. ecosystems and that this is the easiest way to demonstrate the principles. The authors continue their rationale by noting that it is at the ecosystem level that so many human-induced changes are seen and, therefore, this is where readers should focus their thinking. A third reason is given in that the authors aim to integrate classical ecological models with some mathematics arguing that this can increase understanding. What certainly aids understanding is the systematic diagram leading the reader through the text showing how the six sections are related.

Still within the preface/prologue, we start with a brief illustration of the value of ecosystem ecology. Two major environmental issues, one less common today and one more – acid rain and global warming – are used to highlight the value of system study and, at the same time, give and insight into the science which led to the “discoveries” of these issues. This leads us on to section one which focusses on the history and concepts of ecology. It’s a good place to start. In too many areas, learners get just the subject they need but none of the depth to find out where it all connects or in the significance of individual aspects. Having seen the impact of this in action, such grounding is certainly worthwhile.  The three chapters each take a different focus. The first looks at the development of ecology at the ecosystem ecology (so, landscape ecology gets a  mention but molecular ecology does not). Taking the second part of the book’s rationale to heart, it looks at sustainability and Gaia. The second, equally brief, chapter examines a few ecological concepts aimed at ecosystem levels. Divisions of ecology get a mention, as do relationships between temporal and spatial scales and ecological concepts in terms of disturbance, biota and vegetation. The final chapter examines some of the main processes and theories that underpin ecosystem ecology including nutrient flux, steady state and limiting/optimal nutrient levels. We are also introduced to some of the maths (at this stage calculus) that is used in the text.

Section two starts the work in earnest by looking at ecosystem structure and function. Here the work is made clearer by focussing largely on the vegetation and its interactions with the abiotic environment. We start with the Jenny equation and get an overview of soil physics and chemistry and the biomes that can be derived from them. This leads on to water and energy flow through ecosystems. As the focus is on vegetation the next move is towards plant production, not just photosynthetic pathways but also considerations of leaf areas, light efficiencies, respiration and nutrients making this chapter far more complex than its predecessors. A similar level of detail is shown in the work on leaf litter. A too-brief look at species stability gives way to a substantial review of biogeochemical cycles on an ecosystem and then global level. All of this work brings us to a chapter which summarises the work of the section but in a most unusual way. The authors argue for a set of principles which they outline and for which there is evidence in the preceding work. These 17 principles are divided into 5 groups: boundary conditions, energy and water, plant processes, soil processes and nutrient cycling. Looking closely at them one sees some familiar cases but without the usual attribution of their names. for example, Leibig’s Law of the Minimum is reduced to ‘plant growth is limited by some nutrient’. Whereas this is correct, given the audience for the text, one wonders if more sophistication might not have been useful especially given complexity introduced elsewhere. The final chapters of this section relate to changes through time in decreasing order of aeons, millennia and annual.

Section four looks at two main applications of the ideas presented. Air pollution is one case highlighting the issues created by, amongst others, acid rain. Global change is illustrated mainly by nutrient flows. An epilogue draws the work together and suggests it could be used to promote ecosystem services and functioning: the idea that ecology and human health are linked.

This is an interesting text. By looking at the most accessible ecosystems it allows the basic principles to be brought out. The examples are clear and the key concepts clearly explained. Clear diagrams and illustrations help the reader to understand the nature of ecosystem ecology. Set against that, the chapters tend to be variable in both extent and sophistication and this did tend to detract in places. The ’17 principles’ illustrate this point. They provide a clear outline of the most fundamental processes working at the ecosystem level but they could easily have had their correct origins/names identified. Overall, a good text that will allow newcomers to the field to gain a good understanding of the main ideas.

 

 

Leave A Comment