Why Ecology Matters

krebsRating: ★★★★★

Charles J Krebs. 2016. Why Ecology Matters. Chicago University Press. ISBN – 978 0 226 31815 8

I’ll start with an admission – I’ve followed Krebs work for many years and find him one of the most persuasive writers in ecology! Not that I’m biased of course, it’s just I have expectations of this slender text!

The title should be obvious. Of course it matters (providing you want a healthy planet to live on).  I start, suspecting a carefully considered argument for ecology as a science. In these days of budget cuts and research expecting to make money, a study of something that seeks to understand the Earth might not get a mention. The opening words of the preface give me some hope in this direction but that is soon removed. The argument becomes simpler – if we want to understand the principles of the planet, we need to understand the key tenets of ecology. Just as we need to appreciate physics if we need to move, we need ecology to tell us how things are inter-related. Look on this direction with which we have been presented as a chance to develop a tool-kit of key ecological ideas!

The trick here is to find those key principles that underlie ecosystem inter-relationships. Unlike physics or chemistry, there are no obvious ones like gravity and atomic theory; rather, you need to work out what is the minimum number of ideas you should grasp to get the maximum understanding of the topic. Krebs makes this explicit – it’s only as simple as it needs to be and it removes so many of the references essential to professional ecologists but of no value for the lay reader. The issue now comes down to the idea of necessary and sufficient conditions–  has he put in enough detail and no more?

Turning to these key principles, the reader finds 12 brief chapters – one per concept. These titles are not that of conventional ecology (or the other texts he has written as a leading ecologist). They pose questions or at least make statements that demand the reader explores to find out more. Start with the obvious global point – why are plants and animals found where they are? Geographical and climatic barriers would be the obvious points, as they are here, but the treatment each receives is not that of ecological theory but a more gentle exploration of what it is and why it is important. We get the global distribution but he also has a taken the trouble to point out we are less certain about local distribution (which, elsewhere, would appear as the paradox of scale but here is more a footnote). Having given the broad outline the next move is to population sizes and limits. Every organism has its limits and we need to understand them. Again, less a question of scholarly references and more a case of well-chosen examples adding to a beginner’s understanding. At this point, the reader should have noticed a steadily developing logic in the work. Geographical limits and population limits suggests favourable and unfavourable areas and a need to understand why and where this occurs (limiting factors and geographical ranges). There’s also a call to consider how we can change unfavourable into favourable in terms of wildlife conservation and shifting ranges – an indication that the author is looking beyond basic ecology to place his ideas.

The text then turns to more applied matters with two chapters focussing on yields (and the limits/perils of overfishing) and ecosystem recovery after disturbance (either natural or human). The idea of change continues with the next chapter focussing on feeding dynamics. This is not so much the conventional food chain/web but also changes due to what is referred to as “regime shift“. This idea seems to be growing in terms of research and denotes that any set of species can be configured in two or more ways. This is an extension of chaos theory and stable states and not one that might be associated with a tyro’s text but the explanation does help us to understand the response of ecosystems to disturbance: it keeps going but in a different format – very few ecosystems are completely eradicated. This is a relatively recent idea that is growing but is still far from universally accepted. In a similar fashion (although more mainstream) is the idea of keystone species and related terms. The notion that one (or a very few) species might hold the key to the survival of an ecosystem is intriguing but not without critics. However, we must recall the aim of this text and in that context, this adds power to the argument of the need for a basic ecological understanding. Far less controversial (except in some places!), evolution is a key aspect of biology. Usefully, the focus is on recent changes and not the longer-term ideas of speciation. Here it forms a useful reminder of the ways in which systems can alter, and not always in ways that we want or expect. Myxomatosis-resistant rabbits and antibiotic-resistant bacteria are the downside of this process whilst its value in adapting to climate change has yet to be fully explored.

The focus changes with a look towards systems ecology and biogeochemical cycles – key abiotic aspects. Add to this chapters on solar energy and pyramids of biomass etc. and the reader has a sound overview of nutrient movement and the fundamental importance of the sun in driving productivity. The final two chapters form yet another diversion but this time away from theoretical ecology to practical or applied matters. Chapters focussing on climate change and (avoidable) species loss highlight the importance of our actions and how they impede ecosystem functioning.

In this small text of just under 200 pages, Krebs has distilled the essential features from his more usual volumes of three times that size and more! Here, in terms the lay reader can understand, are the most significant concepts of our science. It’s ecology stripped bare – a sharp focus on what really matters. It’s not just that however, it’s also the “why”. Why do we need to know about distributions, ranges, systems etc.? Krebs covers both aspects with his usual flair. As an introductory text that simplifies and enlightens but does not talk down to its readers, this is one of the best texts of recent times. As one expects its well-written and well argued. Given the rise of ecological interest, especially in schools, this really should be seen as the key book for everyone’s shelves.

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