Perspective: Trans-realm biogeography: an immergent interface

Michael N Dawson

doi:10.21425/f5fbg12268

Abstract

perspectives ISSN 1948-6596 Trans-realm biogeography: an immergent inter- face 1 Michael N Dawson School of Natural Sciences, University of California at Merced, 5200 North Lake Road, Merced, CA 953443 USA e-mail: mdawson@ucmerced.edu; http://mnd.ucmerced.edu/ Introduction In his influential paper on geographic speciation in sea urchins and jellyfishes, Ernst Mayr (1954:16) concluded that “marine animals agree in [their] pattern of variation and distribution completely with terrestrial animals.” Yet the sentiment that “it is useless to think of [the sea] as we think of the terrestrial world” (Hardy 1962), i.e. that ma- rine and terrestrial realms are fundamentally dif- ferent, has remained commonplace (e.g. Smeta- cek and Pollehne 1986, Secord 2003). The persis- tence of this bipolar abstraction of the natural world is troubling. Aquatic, atmospheric, and ter- restrial systems can be tightly coupled such that an almost Gaian perspective is needed to meet the challenges of climate change (Menge et al. 2009) yet perceived irrelevance of research from different realms maintains the barriers to multi- disciplinary understanding that slow scientific pro- gress. Background The perception of a vital difference between ma- rine and terrestrial environments, which echoes terrestrial human bias (Smetacek and Pollehne 1986, Hamner 1988, Dawson and Hamner 2008) and ancient Greek natural philosophy, has been propagated in part by the balkanization of 20th century scientific infrastructure (Steele 1995, Sarkar 2005, Stergiou and Browman 2005). Heaney and Lomolino (2009:1-2), for example, noted during their editorial in the first issue of this magazine that “marine and terrestrial biogeogra- phy [have been] discussed in different journals using different terminology”. This lack of meme flow afflicts many relevant disciplines. Menge et al. (2009) bemoaned the lack of cross-referencing between papers in ecological journals serving pri- marily marine or primarily terrestrial audiences. In journals that do cater to both audiences, such as Journal of Biogeography, papers are generally ei- ther marine or terrestrial, and rarely link realms 2 . When marine and terrestrial systems have been discussed together, the environments often are contrasted as having “fundamental differ- ences” (e.g. Steele 1985, Smetacek and Pollehne 1986, Hamner 1988, Thomson and Gilligan 2002, Carr et al. 2003, Lourie and Vincent 2004, Halley 2005). Such a radical position, which implies at least two kinds of ecology, two kinds of evolution, etcetera, is not supported by any empirical study nor enshrined in any biological theory. Dawson and Hamner (2008) thus proposed that concep- tual integration of marine and terrestrial natural history was awaiting only development of a com- pelling quantitative comparative framework. A suitable quantitative comparative frame- work might be provided by expanding Aleyev’s (1977:1) “biohydrodynamic conception of life” in which fluid mechanics provides a suite of tools for comparing the aerial and aqueous fluid environ- 1. ‘Immergent’, a play on ideas, is defined in the Oxford English Dictionary as either “Not merging into something else” or “Erroneous spelling of ‘emergent’, in sense ‘Unexpectedly arising’, ‘urgent’.” 2. A search of Thompson’s Web of Science on 15 November 2009 was conducted for articles containing the topic words ‘marine’, ‘terrestrial’, or ‘marine and terrestrial’ published in the Journal of Biogeography. All titles, and the abstract of papers with ambiguous titles, were read before final categorization. Articles categorized as ‘marine’ (n ≈ 119) or ‘terrestrial’ (n ≈ 139) outnumbered those that discussed ‘marine and terrestrial’ (n ≈ 4) issues; a total of 2842 records for the Journal of Biogeography were recovered, of which 2558 referred to neither “marine” nor “terrestrial” in the fields included in the topic search. © 2009 the authors; journal compilation © 2009 The International Biogeography Society — frontiers of biogeography 1.2, 2009

Highlights

In his influential paper on geographic speciation in sea urchins and jellyfishes, Ernst Mayr (1954:16) concluded that “marine animals agree in [their] pattern of variation and distribution completely with terrestrial animals.” Yet the sentiment that “it is useless to think of [the sea] as we think of the terrestrial world” (Hardy 1962), i.e. that marine and terrestrial realms are fundamentally different, has remained commonplace (e.g. Smetacek and Pollehne 1986, Secord 2003)
Atmospheric, and terrestrial systems can be tightly coupled such that an almost Gaian perspective is needed to meet the challenges of climate change (Menge et al 2009) yet perceived irrelevance of research from different realms maintains the barriers to multidisciplinary understanding that slow scientific progress
In journals that do cater to both audiences, such as Journal of Biogeography, papers are generally either marine or terrestrial, and rarely link realms2

Summary

Introduction

In his influential paper on geographic speciation in sea urchins and jellyfishes, Ernst Mayr (1954:16) concluded that “marine animals agree in [their] pattern of variation and distribution completely with terrestrial animals.” Yet the sentiment that “it is useless to think of [the sea] as we think of the terrestrial world” (Hardy 1962), i.e. that marine and terrestrial realms are fundamentally different, has remained commonplace (e.g. Smetacek and Pollehne 1986, Secord 2003). The potential influence of dispersal, an evolutionary mechanism that has captivated marine biologists for much of the last 30 years (Riddle et al 2008), led Roy and Goldberg (2007) to pose the question, “are marine and terrestrial diversity gradients driven by different processes?”

Results

Conclusion