Scaling mount SAR: Commentary on Matthews et al. (2021) The Species–Area Relationship: Theory and Application

The issue of spatial scaling has grown in recent decades from a minor geeky obsession to mainstream methodological preoccupation virtually all fields science. Increasingly, scientists stripes have been challenged scale up their understanding physical, chemical and even social processes test tube or patch global scales, driven both by the opportunity increasingly sophisticated data sources need address urgent inter-connected challenges. In this respect, as so many others, ecologists well ahead crowd: we field business biodiversity for more than century. main tool doing that upscaling species–area relationship (SAR). SAR percolating collective consciousness biogeographers since late 18th century, but idea was formalised brought wider attention competing works Arrhenius (1921) Gleason (1922). its essence, is simple: area generally contains species. However, sub-additive (twice much less twice species) makes challenge decidedly non-trivial, an inspired theoretical empirical research equal measure. It full century now first became widely appreciated among ecologists, quarter-century last major book on topic (Mike Rosenzweig's Species Diversity Space Time, 1995); it high time someone revisited light work. Fortunately, Tom Matthews, Kostas Triantis Rob Whittaker done just with new book: Species–Area Relationship: Theory Application (2021). ways, Matthews et al. (2021) come stark contrast Rosenzweig’s (1995) volume. While extensive exploration single author's views, volume includes work 44 contributors 35 institutions, spanning 19 chapters almost sub-disciplines. insights perspectives large fraction key players working topic; list reads like Who's Who ecology macroecology researchers: Blackburn Borda-de-Água, Harte Hubbell, Šizling Storch, Thuiller Tjørve, Ugland Ulrich, name few tantalisingly alliterative pairs. If feels spacious expansive (even chatty places), dense tightly stuffed diverse treats, bit claustrophobic places. part result downsized pages fonts: are 20% larger those newer book, words per page about same. Where Rosenzweig had slowly build extended discourse, each stands alone separate narrowly focused account. scattered gems: best account I seen history concept (Chapter 2), valiant attempts generalise SARs ecological function 5) trophic networks 12), applications identify hotspots 13) predict extinctions (Chapters 14 17) more. richness diversity comes at price: despite efforts editors, whole does not (and indeed can't) coherent argument. breadth authorship brings approaches expertise, also inconsistencies style tone, occasional overlaps gaps. On rife terminological inconsistency, editors do good job enforcing common framework all, which largely adhered most authors. They simplify Scheiner’s (2003) influential typology fundamental dichotomy: contrasting ISARs (‘Island’ ‘Isolate’ analyses comparing species sets discrete sites different sizes) saSACs (‘sampling Accumulation Curves’, comparisons across subsamples sizes nested within contiguous areas). distinction clear some internal tensions field, one leaves muddy footprints well. book's section (Part I) initial discussion these issues, detailed concept. This followed series II) discussing aspects diversity: kinds archipelagos, use mathematical functions describe SARs, application ideas functional phylogenetic diversity, properties alien invasions over space. These four rather disparate topics closely linked, interesting; particularly impressed colleagues’ clever Structural Equation Modelling tease apart drivers shapes island database 3). Part III, advances, least rich diverse. Its six range descriptions logical geometrical constraints behind used methods, webs, links between community theory. include lucid explorations Maximum Entropy Neutral theories 10 11) intriguing applying Extreme Value theory 9); itself worth ticket price. then plethora IV), particular exploring uses conservation prioritisation management, finally chapter V) summarising future priorities. there interesting troubling lacunae richness, especially concerning ISAR/saSAC divide. II reasonable mix ISAR saSAC approaches, ‘theoretical advances’ explored III exclusively saSACs. odd worrying considerable literature systems (going back MacArthur Wilson least) hardly enters into discussion; really no advances theory? IV mixture contributions camps once again, bridges conceptual gap extent, ‘relict’ islands formed hydroelectric projects begin become isolates waters rise. Yet, final priorities unaccountably restricts purview alone. missed opportunity: points raised (five seven subheadings covered, my reckoning) could apply equally either variant, issues only (e.g. ‘small effect’) easily be matched saSAC-specific challenges parsing interacting effects sampling intensity). discipline) badly riven perspectives, would better end setting unified integrating agenda future. Throughout examples given models developed independently multiple authors, often apart, frequently languages disciplines. dataset arguably published 1859, 60 years before plotted (in Arrhenius, 1920), random placement individuals produce curved pioneered Rommell (1920) (1920), further 60-plus rediscovered Coleman (1981). suppose ought find worrying—indicating wasted effort, failure appreciate time, tendency ignore non-anglophone consequent keep re-inventing wheels. Nonetheless, found myself oddly cheered our ability rediscover overlooked truths. Decades ago, attended talk Steve Ellner difference ‘noisy’ ‘chaotic’ dynamics. To explain distinction, asked us imagine consequences if prominent ecologist audience were struck lightning moment. We who witnessed immolation course terribly upset experience, noisy, stochastic world, ripples event gradually fade, discipline eventually revert otherwise taken. Conversely, scientific progress chaotic, argued, tragedy grow students colleagues deceased taught, collaborated miss critical interactions insights, turn, passing year spin off along pathways. noisy dynamics perturbations dampen down whereas chaotic they amplified. Our we'd collectively produced past gives me confidence ‘chaotic’. Good may take while germinate, ultimately root, haltingly inexorably ratcheting forward. valuable uneven evidence that: too places, because lot say. We've made decades, provide tide line show how far we've come. waited quarter what respects SAR’s centenary year. wait. author confirms he conflict interest regarding publication contents.