Implicit Scaling in Ecological Research on When to Make Studies of Mice and Men

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. If we place birds on one extreme of the mobility continuum, then large plants would qualify as the other ex treme. Movement in large plants is a low-frequency event because they grow slowly and move to a new site only after a long period of vegetative 2 3 growth. Whereas movement is clearly PC1 an important scaling factor with large plants, an additional criterion is their Figure 1. The first three principal components of the taxon ordination from the binary matrix (Table 3). The ordination of the quantitative deviations from expectation (Table physical size. There are few terrestrial 2) was similar, but the binary ordination gave more distinctive groups. Taxon names organisms, other than large trees, that are abbreviated as in Table 3. dwarf the human observer. Grieg Smith (1971) noted that tropical for ests are certainly diverse, but what is been dominated by any single-minded stoloniferous plants), what distin so impressive is the size of the orga focus on a given concept using a guishes plant from animal movement nisms that display that diversity. As particular taxon. is the time scale of the movement. objects of study, forest plants appear Compared with plants, animals (on suitably scaled for community work, Plants versus animals. The principal average) occupy a larger area or vol particularly succession and ecosystem difference observed in the literature ume in a shorter period of time. Be studies. There is a great block of these was betWeen plants and animals. All cause vagility is a fundamental at large plants and their associated epi animals except mammals cluster tribute of organisms that underlies phytes in the upper right corner of tightly together away from plants in the concept of island biogeography, Table 3, all showing positive associa Figure 1. Although a multitude of we should expect a disparity in re tion with the concepts ecosystem, factors are likely contributors, move search effort on this topic among community, and succession. ment and physical size appear to offer plants and animals. The expected pat Physical size also is an important a critical set of scaling factors that tern is supported with significant (ex scale criterion within plants. Small explain the pattern of separation. ceeding ±3) negative deviations from plants that are not associated with Movement is an obvious scale dif expectation observed for the plant forests form a block in the middle left ference between plants and animals. families Ericaceae and Gramineae of Table 3 that scores above expecta Although there are exceptions (e.g., and significant positive deviations for tion for population-allied studies. consider corals versus dune-running reptiles, birds, and insects (Table 2). This result suggests that a basic dis-

Table 2. The matrix of deviations from expectation for citations after standardization. Boldface indicates greatest deviation. Taxon COMP DIST POPL SYMB EVOL RES CAP ISBIO NICHE HABITAT ECOS COMM succ LICHEN -4.14 -3.45 -4.31 13.20 -3.25 -6.13 2.89 -2.35 1.31 2.17 2.72 1.35 ALGAE -2.67 -3.01 -1.38 7.51 -0.02 1.43 -2.68 -1.98 -2.95 3.80 1.71 2.67 ERIC -1.25 1.04 -1.98 -3.07 -2.70 -2.65 -4.78 -0.41 1.86 1.86 5.69 6.39 TREES -2.48 -0.88 1.92 -2.18 -3.22 -2.56 -1.64 0.14 0.26 4.18 3.63 6.64 BRYO -2.99 -1.33 -3.03 -2.32 -1.23 -3.78 1.56 -0.55 3.87 0.68 5.81 3.35 CONIF -1.56 -0.85 -0.97 -2.30 -3.24 -0.40 0.66 1.03 0.00 4.29 0.65 2.67 GYMN -1.65 -0.89 -1.12 -2.26 -2.43 -0.63 1.56 1.03 -0.08 3.99 0.50 2.41 PTER -2.99 -1.82 -2.14 3.09 4.52 -4.55 -1.29 0.28 2.99 -1.62 1.53 1.97 BASID 2.39 -0.54 0.30 6.27 0.16 -1.64 -2.97 -0.27 1.35 -1.94 -3.29 0.18 ASCOM 7.48 2.26 1.46 2.80 1.64 -4.27 -2.02 -1.54 -1.46 -2.20 -3.27 -0.86 ROSA 1.71 -0.20 2.80 -2.26 -0.85 -1.16 -1.00 -1.40 0.00 -0.40 1.32 1.46 GRAM 2.96 1.05 2.30 -2.09 -0.56 -0.21 -3.24 -0.84 -1.23 1.25 0.72 -0.12 COMP 0.78 1.28 0.32 -3.42 -0.17 0.74 -0.20 -0.47 0.09 -1.75 1.81 1.02 ANGlO 2.53 1.50 2.27 0.58 0.40 -0.95 -2.26 -1.04 -0.87 -0.28 -0.72 -1.20 MAMMAL 2.79 15.52 3.29 -1.21 -0.24 -3.10 -2.53 -2.68 -3.31 -3.08 -1.75 -3.67 FISH -0.65 -2.25 1.48 -1.98 0.63 8.48 -0.75 1.00 -1.17 1.40 -2.10 -4.09 INSECT -0.94 2.44 3.28 0.04 -0.30 3.19 3.65 1.68 -0.77 -1.06 -2.75 -3.62 BIRD 0.34 -0.75 0.95 -3.67 -0.34 2.51 6.22 3.68 1.38 -2.89 -3.37 -4.04 AMPH 2.38 -0.14 0.44 -2.45 6.71 2.68 1.36 0.63 -0.40 -3.38 -3.61 -4.15 REPT -2.00 -4.10 -2.02 -4.27 4.49 13.00 7.87 . 4.08 -0.86 -5.02 -5.21 -5.95

150 BioScience Vol. 41 No.3 Table 3. A binary translation of the matrix in Table 2. Citation occurrences above expectations were scored as 1, and citations occurrences below expectation were scored as zero.Abbreviations in parentheses are used in Figure 1 (rows) and Figure 2 (columns). COMP DIST POPL SYMB EVOL RES CAP ISBIO NICHE HABITAT ECOS COMM succ Taxon (Cp) (Ds) (Po) (Sy) (Ev) (Rc) (Is) (Ni) (Ha) (Ec) (Cm) (Su) LICHEN (Li) 0 0 0 1 0 0 1 0 1 1 1 1 ALGAE (AI) 0 0 0 1 0 1 0 0 0 1 1 1 ERIC (Er) 0 1 0 0 0 0 0 0 1 1 1 1 TREES (Tr) 0 0 1 0 0 0 0 1 1 1 1 1 BRYO (By) 0 0 0 0 0 0 1 0 1 1 1 1 CONIF (Cf) 0 0 0 0 0 0 1 1 1 1 1 1 GYMN (Gy) 0 0 0 0 0 0 1 1 0 1 1 1 PTER (Pt) 0 0 0 1 1 0 0 1 1 0 1 1 BASID (Bs) 1 0 1 1 0 0 0 1 0 0 1 ASCOM (As) 1 1 1 1 0 0 0 0 0 0 0 ROSA (Rs) 1 0 1 0 0 0 0 0 1 0 1 1 GRAM (Gr) 1 1 1 0 0 0 0 0 0 1 1 0 COMP (Cp) 1 1 1 0 0 1 0 0 1 0 1 1 ANGlO (Art) 1 1 1 1 1 0 0 0 0 0 0 0 MAMMAL(Ma) 1 1 1 0 0 0 0 0 0 0 0 0 FISH (Fs) 0 0 1 0 1 1 0 1 0 1 0 0 INSECT (In) 0 1 1 1 0 1 1 0 0 0 0 BIRD (Br) 0 0 0 1 1 1 1 0 0 0 AMPH (Am) 1 0 1 0 1 1 1 0 0 0 0 REPT (Re) 0 0 0 0 1 1 0 0 0 0 tinction exists between population betWeen species appear to be a signif a place on the landscape. Therefore, it and community concepts. The small icant part of nature. is intangible. ness of plants used in population Conceptually, the notion of scale Whereas the physics metaphor and studies allows those populations to b~ and community ecology can be re its focus on interactions offers one easily manipulated in an experimental lated through analogy to periodic view of the community concept, an setting. A characteristic of organisms phenomena. We can think of com alternative conceptualization defines used for population studies is that munity members as having their own communities on the basis of species they are tangible to the investigator. wavelength of longevity, reproduc assembla,ges within definitive geo Communities, on the other hand, ate tion, arid period of movement or a graphical and temporal boundaries. frequently studied with organisms returning pattern of occupancy on This dichotomy notwithstanding, that are too large for any species the landscape (Allen and Hoekstra plants have dominated the commu specific collection to be tangible. Per 1989). nity ecology literature (Table 3). haps communities are intangible in The relationships among different Communities are complex entities, some fundamental way. species involve periods of interaction, and sessility of organisms simplifies as well as periods in which species fail their study. Vagile organisms are in Communities. Communities are com to interact with each other (Schoener herently difficult to observe, which posed of individual organisms inte 1982, Wiens 1977). This on-again, makes study of their interactions dif grated to such an extent that the off-again series of exchanges gives a ficult and identification of the assem processes holding the parts of the resonance among different organism blage's spatial and temporal extent community together cannot be wavelengths. Patterns of organisms enigmatic. With sessile organisms, readily isolated. Therefore, communi on the landscape arise when the re one has the opportunity to observe ties do not appear to be composed of spective periods are close, but not directly species assemblages at scales populations in any simple fashion. identical. Although the relationship consistent with human perception The community is the constraint put among the species coming together by (stnall plants), or, as in the case of on population processes, not the ag happenstance might start as mere res larger plants,

March 1991 151 Populations. Populations, by way of interspecies population-competition is counterpoint to communities, have not to be expected as the sole explan members of all the same species, and atory principle for communities and so each member occupies the land may in fact only be relevant under a scape at a similar scale. Different life limited set of conditions (Connell stages of a species population may 1983, Schoener 1982). Neighborhood

TANSLEY vary in the scale with which they competition, the competition of paired occupy the landscape, but within a individuals, might be relevant in sim life stage the organisms occur at the ple communities, but generally the same scale. Therefore, there is no paired interactions become obscured interference pattern. It follows that long before the scale of the community CLE:Mf::NTS being a collection linked by behavior is achieved. ECOSYSTEM or genetics or both, the population These relationships among compe can be considered as occupying a tition, communities, and populations Figure 2. A schematic representation of place on the landscape at any instant are consistent with the separation of the different scales of perception involved in time. It may move or disintegrate, competition and population from in the irtdividualistic concept of commu but at one instant the population has community in the ordination of con nity (Gleason 1926), viewed from inside a place and therefore is a tangible on cepts (Figure 3 ). The organisms that the community, where the focus is on the the ground .. Accordingly, organisms are used disproportionately often for autonomy of the component species; the superorganismal concept of community that are scaled relative to ourselves population and competition studies (Clements 1905); viewed from outside the such that we can see the collection of are not generally trees, but taxa with community so as to emphasize its integ individuals and their dynamics in a large representations of herbaceous rity; and Tansley's conception (1935) of place are favored for studies of pop plants (Table 3). the ecosystem, viewing the system from a ulation phenomena. Small plants and These same taxa are also used often greater distance, so that the autonomy of animals are strong candidates for this for disturbance studies. The explana the biota is obscured as it is integrated role (Table 3). tion for these patterns in the data is with the physical eiwitonment. The three Although both small plants and an again organism size. Small plants in images of an eye represent the locations of imals exceeded expected population large numbers can be surveyed by the observer. research, only animals (insects and observers on the ground, and mosaics inarnmals) scored above our arbi of populations of different species are component view of community is that trarily selected significance level ( ± 3). commonly apparent. Disturbance Clements dealt almost exclusively One problem with the use of plants, scars can be seen easily. Furthermore, with prairie in Nebraska, whereas lichens, and bryophytes in population growth processes are faster in herba Gleason worked in the forests at the studies is the difficulty identifying in ceous plants, so the disturbance scars edge of the prairie in Illinois. Clem dividual organisms. can be seen to heal in real time. Also, ents viewed the community as a herbaceous plants can be observed to highly integrated and. discrete super Competition. The contrast between jockey for position during a short organism, whereas Gleason saw the communities and populations cart be period. With herbaceous plants, we community as being composed of spe further highlighted by comparing the can observe entire populations, their cies with varying tolerances and re role of competition in the two con competitive dynamics, and their re sponses to environmental factors, re cepts. Interspecific competition has, sponse to disturbance. Competition is sulting in a continuum of species in the recent past, been considered of exactly the right sort of small-scale, corn position. primary importance in explaining fast dynamic to be an explanatory Figure 2 shows how Gleason's in patterns in community structure principle for the outcome of popula dividualistic concept of community is (Murray 1986, Roughgarden 1983, tion interaction of fast-growing her scaled so that the observer is inside Schoener 1982, Strong et al. 1984). baceous plants. It does not matter the system, able to see the parts of the However, elevation of the competi that some trees grow faster than some biota as separate. Being inside the tion concept to a universal principle herbaceous plants, for the consider system, the Gleasonian observer has of community organization was pre ation is not absolute quantity, but is difficulty seeing the whole and its mature. Competition within commu change as judged significant by the emergent properties. Clements' stiper nities can be so recursive that it is human observer. A tree must grow a organismal community emphasizes indistinguishable in the web of inter lot before the observer notices that the integration of the whole, and so actions from such factors as environ the species dominance is shifting. the observer is functionally outside mental heterogeneity, mutalism, and the community system. From this commensalism. Competition is notal Evolution. Much in the tnanner that larger-scaled perspective, a Clements lowed to equilibrate into competitive communities are too large to yield to ian is likely to lose a clear view of the exclusion, a characteristic of the in fine-grained explanations like compe"' independence of the parts of the teractions of unrestrained popula tition, evolution is also likely to re biota. Superficially, the two views ap tions. quire coarse-grained explanations. pear in conflict, but the contradic" In a community, the populations Conventionally, evolution is viewed tions may be more a matter of scale interdigitate so finely that they cannot as the consequence of populations in perspective than reaL be seen to have integrity. Accordingly, competition. Obversely, competition

152 BioScience Vol. 41 No.3 Cp has been described as having both Ds ecological and evolutionary conse 4.3 Po quences (Abrams 1990). If this is in deed the case, then organisms that are Ha Cm 2.3 represented in population and compe Ec tition studies with greater regularity than expected may also receive dis PC2 0.3 proportionate use for evolutionary studies. Our results do not support the idea -1 .7 ! :or "'l······ .· •.·.·.···· , :· that studies of competition between ~~:1· ~:~" .·:.-:".:_··:·.·.·...... _. .. ·.::_.-_·:·.·.:·.·.::·.·.::.:.::-.·_·:: ...... ::;;:.?:::::.::.···· -0.6 0.4 . populations contribute to under standing evolution. Many organisms -3.7 -;----;·~·.. :...j··· .....__· •••-: •• ·~·. ·-~~· :-·················.2... ·~·. ·~··· ~ PC3 -3.7 ······ apparently well suited to studies of -1.7 0.3 competition do not emerge among 2.3 those used in an abundance of evolu 4.3 tionary studies (Table 2). In the ordi PC1 nation of concepts (Figure 3), evolu Figure 3. The first three principal components of the concept ordination from the binary tion is nowhere near the population matrix (Table 3). The ordination of the quantitative deviations from expectation (Table competition-disturbance concepts. 2) was similar, but the binary ordination gives more distinctive groups. Concept names Taxa emerging as favorites for evolu are abbreviated as in Table 3. tionary studies are at first a strange mixture: reptiles, amphibians, and pteridophytes. However, they are all have to be seen as separate individu group of habitat, community, succes ancient orders. The long lineage ap als or taxa, but rather they are inte sion, and ecosystem in the upper pears to be the critical scaling feature grated with the physical environment right. This latter group also gains of evolution. through process (O'Neill et al. 1986). cohesion by a strong negative associ The ecosystem view of T ansley ation with animals. The ordination of Ecosystems. Organisms are not usu (1935), where the observer is outside taxa (Figure 1) similarly gives three ally identifiable as entities in the con of a system that integrates the biota distinct groups, each with its easily cept of ecosystems. Rather, they are and its physical environment, appears interpretable, distinctive scale charac part of pathways that may involve to involve a more coarse view of the teristics: big forest plants and their only parts of the organism (e.g., tree world than used by community ecol associates, small plants, and animals. roots) or guilds (e.g., mycorhizae). ogists (Figure 2). Note that grasses, as The analysis we present has been The functional ecosystem ·is a black the undefined species of primary pro biased by our backgrounds. Others box, which is reflected in the very duction for grazers, occur in ecosys with different frames of reference will strategy of input/output modeling. In tem studies, whereas Compositae ·in undoubtedly have suggestions for ad terms of observation scale, the ob their petaloid splendor do not. Be ditional taxon/concept keywords and server is operationally outside the sys cause of their taxonomic intransi will observe different patterns and tem and thus the organisms are not gence (one needs a hand lens to key pairings. For example, animal ecolo apparent, even though the biota are them out), grasses are naturals for a gists might note that niche and island an important part of the system. role in a conception of nature that biogeography concepts seem to have Given this property of the ecosys calls all green material one thing a close association in Figure 3. Also tem concept of nature, taxa that live primary production. evolution and symbiosis show poten in habitats where the ecological ob tial for a conceptual relationship. server cannot see them are likely can Analysis summary. The unique scale Neither of these pairings met our didates for ecosystem studies. Ani of the observer in relation to the criteria for significant deviation from mals are consistently negatively taxon and ecological concepts studied expectation, but they point toward associated with the ecosystems (Table is elucidated by the analysis results. In opportunities for further study. The 3), with the exception of fish. This both the ordinations of concepts and merit of this type of analysis, there exception highlights the nature of taxa, the clusters are too tight and are fore, is not just in its depiction of how ecosystems and their relationship too easily explained to be spurious ecological research has been con with the human observer and is ex depictions of how ecology has been ducted, but, more important, in its pected if the taxon represents a func studied. High on the second compo heuristic tendency to encourage fur tional ecosystem compartment, as fish nent axis of the concept ordination ther investigation among an eclectic do for secondary consumption and (Figure 3) are two well~defined clusc group to uncover scale-dependant re nutrient storage. Similarly, algae are ters, at opposite ends of the first com lationships. unseen (as individuals or species) pri ponent axis. The positive association mary-production and nutrient-cap of the small plants with competition, Conclusions ture compartments, explaining their population, and disturbance yields high score in the ecosystem column. the tight cluster on the left; the forest As a preliminary to any ecological In the ecosystem, the biota do not taxa are responsible for the distinct study, ecologists organize their

March 1991 153 thoughts around a set of tangibles, finished moving. It moves fast be University of Chicago Press, Chicago. many of which are organisms. How cause it gets to its destination before Carlile, D. W., J. R. Skalski, J. E. Batker, J. M. Thomas, and V.I. Cullinan. 1989. Determi ever, th~ scaling of organisms is far the human observer could. Because nation of ecological scale. Landscape Ecol. from simple. Scales intrinsic to the science hopes to enhance understand 2: 203-213. organism include: size, the time peri ing, necessarily in human terms, it Clements, F. E. 1905. Research Methods in ods associated with reproduction, may not be bad that ecology is scaled Ecology. Arna Press, New York. longevity, and rates of movement. Be in human terms. Rather ·than fight Connell, J. H. 1983. On the prevalence and yond this simple group are extrinsic relative importance of interspecific competi human nature, ecologists are well ad tion: evidence from field experiments. Am. factors: scaling relative to other orga vised to be explicit about the scales Nat. 122: 661-696. nisms, scaling relative to the physical they use, so that they can anticipat~ Gleason, H. A. 1926. The individualistic con environment, anq scaling relative to the consequences of decisions that cept pf the plant association. Bull. To"ey patterns of human perception. To were formerly made subconsciously. Bot. Club 53: 1-20. Golley, F. 1989. A proper scale. Landscape deal with the interactions of these By modeling with appropriately Ecol. 2: 71-72. differently scaled organisms, the ecol scaled concepts, ecologists can hope Grieg-Smith, P. 1971. Application of numerical ogist employs various abstractions to advance with fewer delusions of methods to tropical forest. Pages 195-206 in that also have an implicit scale rela objectivity, but more consensus. By G. P. Patil, E. C. Pielou, and W. E. Water's, tive to the organism. Some of these recognizing the importance of relative eds. Statistical Ecology. vol. 3. Pennsylvania State University Press, University Park. scales mesh more easily than others, scaling inside concepts as well as in Mcintosh, R. P. 1973. H. A. Gleason and so various concepts associate the scale of tangibles, ecologists can individualistic ecologist 1882-1975. Bull. with particular types of organisms in hope to match best the questions to Torrey Bot. Club 102: 253-273. ecological research. Sometimes an in the study site, compatible concepts, Meentemeyer, V., and E. 0. Box. 1987. Scale sistence on some particular type of and data. · effects in landscape studies. Pages 15-34 in M. G. Turner, ed. Landscape Heterogeneity explanation forces incompatible We are not reporting ecology the and Disturbance. Springer-Verlag, New scales together. · way it should be studied, but rather York. In this article, we have used the the prevalent way it is studied. Ecol Milne, B. T. In press. Lessons from applying patterns of success in the past, mani ogists who find themselves focusing fractal models to landscape pattern. M. G. fested in the broad patterns in pub on an area that received less than Turner and R. H. Gardner, eds. Quantitative Methods in Landscape Ecology. Springer lished research, to describe the match expected attention might take note of Verlag, New York~ ing of the study site and organisms the fact that they are taking an unor Murray, B. G. 1986. The structure of theory, with concepts. From this investiga thodox stance, and thereby they and the role of competition in community tion, it emerges that the mobility of might be able to step beyond conven dynamics. Oikos 46: 145-158. animals makes them difficult concep tional wisdom. O'Neill, R. V., D. DeAngelis, J. B. Waide, and T. F. H. Allen. 1986. A Hierarchial Concept tual bedfellows with plants. Botanists of Ecosystems. Princeton University Press, have reason for their world view be Princeton, NJ. ing at odds with that of the zoolo References cited Pattee, H. H., ed. 1973. Hierarchy Theory: The gists. Rather more surprising, herbs Abrahamson, W. G., T. G. Whitham, and P. Challenge of Complex Systems. Braziller, apparently cannot be readily studied W. Price. 1989. Fads in ecology. BioScience New York. Roughgarden, J. 1983. Competition and theory alongside larger plants, because the 39: 321-325. Abrams, P. A. 1990. Ecological vs. evolution in community ecology. Am. Nat. 122: 583- difference in scale means that it is ~ry consequences of competition. Oikos 57: 601. difficult to find a set of unifying con 147-151. Schoener, T. W. 1982. The controversy over cepts that apply in the same way to Allep., T. F. H., and T. W. Hoekstra. 1990. The interspecific competition. Am. Sci. 70: 586- such a heterogeneous set of orga confusion between scale-defined levels and 595. nisms. conventional levels in organization in ecol Strpng, D. R., D. Simberlpff, L. G. Abele, A. B. ogy. journal of Vegetation Science 1: 5-12. Thistle, eds. 1984. Ecological Communities: Despite their best efforts to achieve Allen, T. F. H., R.. V. O'Neill, and T. W. Conceptual Issues and the Evidence. Prince objectivity, ecologists use a remark Hoekstra. 1984. Interlevel relations in eco ton University Press, Princeton, NJ. ably provincial set of relative scales. logical research and management: some Tansley, A. G. 1935. The use and abuse of Big and small, fast and slow, and near working principles from hierarchy theory. vegetational concepts and terms. Ecology and far are scaled relative to human USDA Forest Service General Technical Re 16: 284-307. port RM-110. Rocky Mountain Forest and Wiens, J. A. 1977. On competition and vari size, longevity, mobility, and acuity. Range Experiment Station, Fort Collins, CO. able environments. Am. Sci. 65: 590-597. Ecologists say that a bird moves far Allen, T. F. H., and T. B. Starr. 1982. Hierar __ . 1989. Spatial scaling in ecology. because they cannot see it when it has chy: Perspectives/or Ecological Complexity. Funct. Ecol. 3: 385-397.

154 BioScience Vol. 41 No.3