perspective: Musings on the Acropolis: Terminology for biogeography

ISSN 1948‐6596 opinion and perspectives perspective Musings on the Acropolis: Terminology for biogeography Samuel M. Scheiner Division of Environmental Biology, National Science Foundation, 4201 Wilson Blvd., Arlington, VA 22230, USA. e‐mail: sscheine@nsf.gov; http:// www.nsf.gov/staff/staff_bio. jsp? lan=sscheine Abstract. Biogeography, like all science, is better served when its vocabulary usage is precise, organized and simple. In this light, I examine three intertwined sets of concepts concerning scale and diversity. First, I show how ‘scale’ consists of four components: sampling unit, grain, focus and extent. Using those more precise terms prevents potential ambiguities in communication. I also clear up a confusion in the usage of ‘focus’ that I promulgated in an earlier paper. Second, I explain how organizing our concepts concerning species richness relationships both disambiguates those concepts and leads to the develop‐ ment of new theories. Third, I explore the multitudinous ideas and terms that have collected under the general concept of ‘diversity’ and propose one scheme for simplifying current confusions. Biogeography is in a period of unification of its disparate threads of ecology, phylogeography and phylogenetics. In weaving together concepts of scale and diversity, I hope that this essay contributes to that unification. age to those ancient Greek philosophers who gave us the foundations of our sciences. Introduction More precise vocabulary “Rhetoric is the art of ruling the minds of men. ” (Plato) “Sticks and stones may break my bones, but words will never hurt me. ” (Child’s rhyme) On the contrary, words matter. They solidify con‐ cepts and ensure accurate communication. Im‐ properly used, they can obscure and sow confu‐ sion. Ecologists are notorious for inventing com‐ plex lexicons, although we are probably no worse in this regard than many other disciplines and pro‐ fessions. Sometimes those lexicons make mean‐ ings precise, but only if used properly. My purpose here is to examine three intertwined sets of con‐ cepts concerning scale and diversity, with a goal of making our vocabulary usage more precise, organ‐ ized and simplified. While none of this is new, our continued misuse of terminology bears its repetition. This essay was conceived while at the Fifth Interna‐ tional Biogeography Society meeting in Crete, lis‐ tening to the talks and their misuses and ambigui‐ ties of rhetoric. Having come down with the ’flu a short time later, I spent an entire day in my hotel room writing this paper while gazing up at the Acropolis, hence the title of this piece. It is a hom‐ “It is the mark of an educated man to look for pre‐ cision in each class of things just so far as the na‐ ture of the subject admits; it is evidently equally foolish to accept probable reasoning from a mathematician and to demand from a rhetorician scientific proofs. ” (Aristotle, Nicomachean Ethics) Biogeography deals with patterns and processes that vary in time and space from seconds to ep‐ ochs and micrometers to the entire globe. In re‐ ferring to these ranges of time and space, we make one of the most common vocabulary errors in our discipline by talking about differences in ‘scale. ’ Because ‘scale’ has multiple components (Table 1A), the use of the word ‘scale’ is often im‐ precise (Dungan et al. 2002). Most often what is meant is ‘extent’ – as in, “Studies at landscape and continental scales” – and this meaning is usu‐ ally, but not always, obvious in context. The other frequent meaning of ‘scale’ is ‘grain. ’ It is here that the use of ‘scale’ can sow confusion. Consider the following: “The accuracy of species richness data differs when compiled at landscape and continental scales. ” That sentence © 2011 the authors; journal compilation © 2011 The International Biogeography Society — frontiers of biogeography 3.2, 2011