Plant Soil (2009) 322:87–89 DOI 10.1007/s11104-009-0096-9
COMMENTARY
New lessons from ancient history Peggy Fiedler
Received: 10 June 2009 / Accepted: 26 June 2009 / Published online: 17 July 2009 # Springer Science + Business Media B.V. 2009
Keywords OCBIL theory . YODFEL . Biodiversity . Conservation . Old landscapes . Interfile soils . Climate . Rare species . Evolution . Dispersability . Endemism . Persistence . Salinity . Speciation
In 1984, an Ecological Society of Australia (ESA) symposium was convened to explore the effects of evolutionary history on species assemblages within similar present-day environments. Australian ecosystems were deemed to be the perfect natural laboratories because significant portions of that island continent have been more or less undisturbed by sea-level rise, glaciation, volcanism, etc. since the early Cretaceous. As such, many can be contrasted with younger temperate landscapes in the Northern Hemisphere with similar climatic conditions to elucidate evolutionary patterns. Professor Mark Westoby, of Macquarie University, summarized key findings of the symposium (Westoby 1988), beginning with an introductory quotation from the writings of François Péron, zoologist on the 1801–1803 Baudin expedi-
Responsible Editor: Hans Lambers. P. Fiedler (*) WSP Environment & Energy, LLC, 160 Franklin St., Suite 300, Oakland, CA 94607, USA e-mail:
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tion, commissioned to chart the Australian coast. Péron’s comment bears repeating: . . . it would seem . . . as if . . . the animals and vegetables of this singular continent [have] peculiar laws, which differ from all the principles of our sciences and all the rules of our systems (Péron 1809). Apparently, Péron, a truly prescient naturalist, was spot on. Exactly 200 years since, one of Australia’s native sons, Stephen D Hopper, Director of the Royal Botanic Gardens, Kew, has tackled the development of an integrated theory of biodiversity evolution and conservation in ancient landscapes. Péron’s “peculiar laws” – still in their infancy as OCBIL theory – posits that biodiversity ecology and evolution on old, climatically buffered, infertile landscapes (thus, “OCBIL”) are fundamentally different from the equivalent processes that occur on younger landscapes. OCBILs are rare from a global perspective, but are found especially in the Southwest Australian Floristic Region (SWAFR, Hopper and Goia 2004), South Africa’s Greater Cape and the Pantepui Highlands of Venezuela. Much more common are YODFELs – young, often disturbed, fertile landscapes (thus, “YODFEL”), which are found worldwide, including within ancient ones. Péron’s peculiar laws are offered by Hopper (2009) and are supported by seven sets of eminently testable
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Fig. 1 Eucalyptus caesia ssp. magna illustrates several OCBIL hypotheses. Only 2120 individuals are known in the wild, distributed across 18 granite outcrops in Western Australia’s semiarid Wheatbelt (Nikulinsky and Hopper 2008). In addition, this eucalypt exhibits very high levels of population divergence but low intra-population variation (Byrne and Hopper 2008), extremely limited seed dispersal and vertebrate (bird) pollination. Illustration is from Nikulinsky and Hopper (2008) and reproduced courtesy of the artist (Copyright Philippa Nikulinsky, Life on the Rocks, Published by Fremantle Press 2008)
hypotheses. They include the proposition that OCBILs demonstrate (1) reduced dispersability among plant species, (2) elevated persistence of lineages and of long-lived individuals, (3) selection of traits that maximize heterozygozity in small plant populations, (4) prolonged speciation at the margins of major climatic zones, (5) plants with nutritional and other biological specializations for survival on infertile soils, (6) adaptation to saline soils, and (7) unusual resiliences and vulnerabilities of plant species to habitat fragmentation and site disturbance. Some of these ideas already have been have been named and vetted. For example, the ‘Gondwanan Heritage Hypothesis’ refers to the proposition that ancient landscapes should support a greater number of relatively old lineages, population systems and long-lived individuals (Fig. 1, Hopper et al. 1996); extreme clonality coupled with little or no genetic variation is described by the ‘Ultimate Self Hypothesis’ (Hopper and Barlow 2000); and long bouts of speciation occur in semi-desert regions, a phenomenon coined by Hopper (2005) as the ‘Semiarid Cradle Hypothesis.’ The genius of OCBIL theory, however, is its comprehensive yet confidently divergent synthesis of mainstream evolutionary and ecological theory. Given that biologists worldwide are celebrating the 150th anniversary of a revolutionary new theory offered in 1859 (i.e. Darwin’s theory of evolution by descent with modification), it seems fitting that a complementary theory of biodiversity evolution in ancient landscapes be offered for a test drive in 2009. Hopper developed OCBIL theory after more than thirty years of field work, primarily on three continents (Australia, Africa and North America). A professional life in the field provides a powerful basis for theoretical insights, as the legendary American baseball hero Babe Ruth once quipped (in another profession of course), “there’s no substitute for field time.” Certainly the same could be said for the 19th-
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century naturalist explorers Alfred Russel Wallace, Henry Bates and Richard Spruce all of whom also made fundamental contributions to the fields of evolution, biogeography, botany, zoology, entomology and natural history after decades in the field on several continents in both hemispheres. Hopper also has had the privilege of brilliant mentors, generous colleagues and a series of professional home bases that fostered (or at least facilitated) his keen powers of observation and deductive reasoning. Beyond the intellectual contribution, why is OCBIL theory important? A quick scan of the more popular conservation biology (e.g. Groom et al. 2006; Primack 2006) or topical (e.g. Collinge 2009) texts shows that the conservation science that has been developed in the last several decades offers a set of generalized guiding principles and theory to govern conservation activities globally. Perhaps this is a function of the meteoric development of conservation biology as a new integrative science, the undeniable urgency of effective conservation efforts or some combination of the two. But conventional conservation biology theory does not necessary work to the advantage of OCBIL biota. For example, based upon OCBIL theory, Hopper (2009) argues convincingly that, all else being equal, small landscape fragments are not necessarily less worthy of preservation, corridors are not a panacea for wildlife protection, and restoration efforts in ancient soils face unique challenges that are not readily resolved by YODFEL solutions of supplemental chemical fertilization and mycorrhizal inoculation. When various and oft conflicting algorithms are being argued for setting conservation priorities, particularly those scientists advocating the use of economic models as a basis for decision-making (e.g. Wilson et al. 2007), understanding and addressing landscape histories will surely be crucial to getting it right. The inaugural publication of potentially controversial ideas, especially those global in scale, is bound to generate doubt, dismissal and disingenuous praise in addition to an honest embrace. Yet the development of such a comprehensive new evolutionary theory relevant to several of the world’s most diverse biodiversity hotspots demands that it be taken seriously, and that its key theoretical struts are tested for their soundness and application. Which is why the 1984 ESA symposium’s central question – “. . . how important is the long evolutionary history that shaped the biology of the component species and led to
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those components assembling at a particular place?” Westoby (1988:549)—is a great place to begin. Comprehensively and confidently, Hopper (2009) has shown that the answer to the 1984 symposium question is “very important” – how and why is up to conservation and evolutionary biologists to fill in the myriad details. Ultimately, OCBIL theory provides us with a generation or more of testable hypotheses, many in the service of biodiversity conservation.
References Byrne M, Hopper SD (2008) Granite outcrops as ancient islands in old landscapes: evidence from the phylogeography and population genetics of Eucalyptus caesia (Myrtaceae) in Western Australia. Biol J Linn Soc 93:177–188 Collinge SK (2009) Ecology of fragmented landscapes. John Hopkins University Press, Baltimore MD Groom MJ, Meffe GK, Carroll CR (2006) Principles of conservation biology, 3rd edn. Sinauer Associates, Sunderland MA Hopper SD (2005) Deserts through time. In: Nikulinsky P, Hopper SD (eds) Soul of the desert. Fremantle Arts Centre Press, Fremantle, pp 10–23 Hopper SD (2009) OCBIL theory: towards an integrated understanding of the evolution, ecology and conservation of biodiversity on old, climatically buffered, interfertile landscapes. Plant Soil doi:10.1007/s11104-009-0068-0 Hopper SD, Barlow BA (2000) Sidney Herbert James 1933– 1998. Aust J Bot 48:287–295 Hopper SD, Goia P (2004) The southwest Australian Floristic Region: evolution and conservation of a global hot spot of biodiversity. Ann Rev Ecol Evol Syst 35:623–650 Hopper SD, Harvey MS, Chappill JA, Main AR, Main BY (1996) The Western Australian biota as Gondwanan Heritage — a review. In: Hopper SD, Chappill JA, Harvey MS, George AS (eds) Gondwanan heritage: past, present and future of the Western Australian Biota. Surrey Beatty & Sons, Chipping Norton, NSW, pp 1–46 Nikulinsky P, Hopper SD (2008) Life on the rocks. The art of survival, 2nd edn. Fremantle Arts Centre Press, Fremantle Péron M (1809) A Voyage of Discovery to the Southern Hemisphere, Performed by Order of the Emperor Napoleon, During the Years 1801, 1802, 1803 and 1804. Richard Phillips, Bridge St., Blackfriars, London (Translated from French) Primack RB (2006) Essentials of conservation biology, 4th edn. Sinauer Associates, Sunderland MA Westoby M (1988) Comparing Australian ecosystems to those elsewhere. BioScience 38(8):549–556 Wilson KA, Underwood EA, Morrison SA, Klausmeyer KR, Murdoch WW, Reyers B, Wardell-Johnson G, Marquet PA, Rundel PW, McBride MF, Pressey RL, Bode M, Hoekstra JM, Andelman S, Looker M, Rondinini C, Kareiva P, Shaw MR, Possingham H (2007) Conserving biodiversity efficiently: what to do, where, and when. PLoS Biology 5(9):1850–1861
