This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. Implicit Scaling in Ecological Research On when to make studies of mice and men Thomas W. Hoekstra, Timothy F. H. Allen, and Curtis H. Flather cology focuses on tangible or­ awareness of scale-dependent rela­ E ganisms; ecological complexity tionships among organisms and eco­ results from the myriad of pat­ Various concepts logical concepts and the implications terns with which the many different associate with of these relationships. The tangibility types of organisms interact in their and familiarity of the organisms the environments. Yet ecology is by no particular. types. of ecologist counts or manipulates can means devoid of abstraction. To pro­ organisms tn lead to a false sense of objectivity. duce general principles out of the Considering scale in an explicit man­ mass of complicated natural histories, ecological research ner should result in measured judge­ ecology is replete with concepts, such ment instead of the happenstance of as competition, evolution, and succes­ unwitting choice. sion, and abstruse structures, such as communities and ecosystems. al. 1989, Golley 1989, Meentemeyer Identifying the human scale in The diversity of organisms and eco­ and Box 1987, Milne in press). the ecological literature logical concepts has always threat­ In this article scale is defined by the ened to bury ecologists in a profusion temporal and spatial characteristics We conducted a computer-assisted of special cases. However, the notion of energy and matter within and literature search on words found ei­ of scale offers a framework for order­ among ecological systems. The scale ther in a title or in an author's list of ing nature that may help reveal gen­ of a study is determined by the size keywords. A total of 23 taxa and 12 eralities from the mass of particulars. and extent of the observations in time ecological concepts were used as key­ Whereas the idea of scale is intuitively and space, as well as the resolving words for the search (Table 1). Some familiar to ecologists, the vagueness power of the individual measure­ of the taxa overlap or subsume each of intuition has contributed to ambi­ ments (Allen et al. 1984). We also other, coming as they do from various guity in defining and understanding subscribe to the premise that scale is levels at and above the family level. the concept. Although formal ecolog­ defined by the observer. Scale may be For example, both conifers and gym­ ical treatment of scale has been initi­ defined as large or small only in rela­ nosperms were used, the former being ated in a collection of ideas called tion to some reference-a benchmark an important group defining a biome, hierarchy theory (Allen and Starr that is often the scale of human ob­ whereas the latter is a taxonomic dis­ 1982, O'Neill et al. 1986, Pattee servers and their primary experiences. tinction equivalent to flowering 1973 ), varying uses of scale remain in Despite emerging principles of plants or fern allies (these two plant the ecological literature (see Carlile et scale, an ecologist's choice of scale for groups were also targeted). Some taxa a study is often implicit in the selec­ that were searched separately were tion of the study organism or ecolog­ aggregated for the analysis, such as ical concept. It was our supposition families consisting primarily of trees. Thomas W. Hoekstra is an assistant direc­ that the often unrecognized relation­ Any given reference could be entered tor of the Rocky Mountain Forest and ship between organism/concept and under several keywords and so could Range Experiment Station, Fort Collins, scale should determine that some or­ be represented in the data more than CO 80526. Timothy F. H. Allen is a ganisms pair with certain ecological once. professor in the Botany Department at the University of Wisconsin, Madison, WI concepts. We investigated the ecolog­ The computer searched Biosis Pre­ 53715. Curtis H. Flather is a research ical literature to discover whether views, a database of citations that wildlife biologist at the Rocky Mountain concepts and organisms were indeed draws on almost 9000 primary biology Forest and Range Experiment Station, paired. With this retrospective exam­ journals, symposia, reviews, prelimi­ Fort Collins, CO 80526. ination, we hope to raise ecologists' nary reports, semipopular journals, se- 148 BioScience Vol. 41 No.3 lected institutional and government re­ Table 1. The list of search keywords and abbreviations. ports, and research communications. Organism taxa Ecological concepts The search covered the period January Algae (ALGAE) Disturbance (DIST) 1969 to November 1984. Ascomycetes (ASCOM) Succession (SUCC) In the raw matrix, containing al­ Basidiomycetes (BASID) Evolution (EVOL) most 339,000 references, some taxa Bryophyta (BRYO) Community (COMM) were associated with many more pa­ Pteridophyta (PTER) Ecosystem (ECOS) pers than others. The keyword mam­ Gymnospermae (GYMN) Island biogeography (ISBIO) mal, for example, retrieved more than Coniferopida (CONIF) Habitat (HABITAT) 127,000 citations, whereas bryophyta Angiospermae (ANGlO) Niche (NICHE) retrieved less than 2000 citations. No Salicaceae* Population (POPL) taxon or concept scored so few cita­ Rosaceae (ROSA) Resource capture (RESCAP) tions as to be excluded from the anal­ Gramineae (GRAM) Symbiosis (SYMB) Betulaceae• Competition (COMP) ysis; island biogeography was the rar­ Compositae (COMP) est category, with only 470 citations. Fagaceae• This study did not ask which orga­ Juglandaceae• nisms were studied most; therefore, Ericaceae (ERIC) the number of citations was standard­ Insects (INSECT) ized first by taxon row and then by Fish (FISH) concept column to yield a standard­ Amphibians (AMPH) ized measure of effort devoted to each Reptiles (REPT) pair of taxon and ecological concept. Birds (BIRD) The data in the standardized matrix Mammals (MAMMAL) Lichens (LICHEN) were inspected for the largest devia­ tions from that expected from a ran­ *Indicates taxa that were aggregated as TREES for purposes of analysis. dom pairing of organism and con­ cept. Deviation from expectation was effort; that the keywords reflect fun­ matrix is an expression of only that defined as the difference between the damentals of human perception of one concept-taxon pair. Given the observed (literature search) and ex­ nature, rather than fashion in edito­ subtlety of the signal, any clear pat­ pected (random pairing) research ef­ rial policy (Abrahamson et al. 1989); tern that does emerge is likely to be fort for each taxon/concept pair (Ta­ and that our data transformation pre­ reflective of a general trend across the ble 2). We identified potentially served taxon/concept relationships. entire discipline. significant deviations by two criteria: We recognize that we may have For many of the relationships there deviations that exceeded ±3 and de­ missed some articles because they did is little a priori basis for anticipating viations that were consistent in sign not have the critical words in the the outcome. However, some con­ within a group of taxa or concepts. strings that we searched. However, cept/taxon associations must satisfy Groups were defined by inspecting authors' decisions not to flag a con­ classical biological relationships, oth­ the data matrix. cept or taxon is a reflection of their erwise the assumptions underlying For the final analysis, the devia­ mind-set, which is part of what we the whole study are unsupported. If tions matrix was transformed to bi­ wished to study. We also recognize lichens are not the principal organism nary form, with values above expec­ that scientific disciplines define some associated with symbiosis and that tation being scored as 1 and values key words uniquely or use different relationship is not secondarily re­ below expectation being scored as 0 key words for the same concept. We flected in the citations of algae and (Table 3). The validity of our original did not investigate these different uses fungi (the taxa of the mutualism), supposition was examined by subject­ of key words. then the entire study must be suspect. ing the binary matrix to principal Table 2 does show one of the greatest component analysis, to depict graph­ Patterns in positive deviations (13.20) from ex­ ically the relationships among con­ organism/ concept relationships pectation to be between lichens and cepts and taxa through simple ordi­ symbiosis. nation. This method of analysis is From an examination of Table 2, it is Although it is not likely that the primarily used for data exploration immediately apparent that the devia­ data set contains artifacts arising and therefore associated with hypoth­ tions from expectation are subtle. No from arbitrary editorial policy, there esis generation, but failure to observe deviation is larger than the 15 over is reason for concern that the results pattern in the principal component expectation scored by mammals for could be influenced by scientific fash­ ordinations would certainly render disturbance, and most deviations are ion dictated by factors that have our original supposition suspect and less than ±4. This homogeneity is nothing to do with biology. One such would indicate that further probing reassuring for the multivariate analyst factor could be founder effects in a of detailed hypotheses would be un­ and suggests that the results are not given discipline where an organism, warranted. spurious artifacts deriving from the once picked, becomes the model of The primary assumptions for our methods of analysis. If some of the choice because of precedence. Fortu­ interpretation were that the number deviations from expectations were nately, the data set appears homoge­ of citations is a reflection of research large, then one might fear that the nous and the relationships have not March 1991 149 An,As Bs - Although the majority of the plant 2.9 taxa examined do not show strong Rs negative deviations, the consistency in 1.9 the deviation (10 out of 14 plant 0.9 taxa) provides secondary evidence for the scaling difference between plants PC2 -0.1 and animals based on mobility.