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Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
Comments on the theory of holocene refugia in the culture history of amazonia
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Comments on the theory of holocene refugia in the culture history of amazonia

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  • 1. Society for American ArchaeologyComments on the Theory of Holocene Refugia in the Culture History of AmazoniaAuthor(s): Richard G. WhittenSource: American Antiquity, Vol. 44, No. 2 (Apr., 1979), pp. 238-251Published by: Society for American ArchaeologyStable URL: http://www.jstor.org/stable/279074 .Accessed: 25/04/2011 23:42Your use of the JSTOR archive indicates your acceptance of JSTORs Terms and Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp. JSTORs Terms and Conditions of Use provides, in part, that unlessyou have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and youmay use content in the JSTOR archive only for your personal, non-commercial use.Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at .http://www.jstor.org/action/showPublisher?publisherCode=sam. .Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printedpage of such transmission.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org.Society for American Archaeology is collaborating with JSTOR to digitize, preserve and extend access toAmerican Antiquity.http://www.jstor.org
  • 2. COMMENTS ON THE THEORYOF HOLOCENEREFUGIAIN THECULTUREHISTORY OF AMAZONIARichardG.WhittenThe theory of Holocene refugia in Amazonia as offered by B. J. Meggers is discussed in terms of dating,climateanalysis, ecology,and linguistics.Thereis strongevidence to suggestthatMeggersformulationmaybe premature.RECENTLYTHEREHAVE BEEN SEVERALATTEMPTS at reconstructing the Quarternary pa-leoecology of Amazonian South America. Of interest to archaeologists is Betty J.Meggers (1974,1975, 1977) adaptation of a hypothesis developed by J. Haffer (1969, 1974). This hypothesis sug-gests drastic climatic, floral, and faunal discontinuities in the regions past. Meggers invocationof Haffers model involves an attempt to explain the distribution and diversity of languages inAmazonia by means of certain migrations in and around posited refugia of tropical vegetation.These comments will summarize Haffers model and Meggers adaptation of it, offer somecriticisms, and make some alternative suggestions.Haffer has proposed that the diversity and distribution of avian species in the Amazonianregion can only be explained if extreme changes in the ecology are posited (1969, 1974).Specifically Haffer suggests the existence of Pleistocene "refugia," islands of tropical forest sur-rounded by grassland savanna (see Figure 1). These are presumed to have been coeval withglacial periods in the Northern Hemisphere. Normal or interglacial periods saw a return of theforest into the savanna areas. This hypothesis has been accepted by other biologists working inthe region (e.g., Vuilleumier 1971; Muller 1973; Vanzolini 1973; Prance 1973; Brown et al. 1974).The sizes and locations of these centers of origin and dispersal vary, however, depending on thespecies studied (cf. Vanzolini 1973:Figure 1). It should be stated at the outset that actual evidencefor any drastic paleofloral changes due to extreme and widespread aridity in Amazonia is prac-tically nonexistent (Van der Hammen 1975).Even as there is little paleoecological evidence to support this hypothesis, there are argumentsthat can be made against it. The archaeologist is immediately struck by the similarity of this ideato V. Gordon Childes oasis theory of domestication. Both utilize a model of extreme ecologicalchange as a deus ex machina to explain changes that otherwise seem unexplainable. The Amazo-nian refugia model can be shown to be a similarly premature attempt. Several flaws, to bediscussed in detail below, are already obvious.Meggers does not refer to any criticism of Haffers hypothesis. She has simply accepted it andexpanded it to include the presence of refugia during a postulated arid episode in the Holocene(ca. 4000-2000 B.P.). This use of the concept is in spite of Haffers own reluctance to apply hismodel to the ecology of the Holocene (1974:149). Muller (1973) and Vanzolini (1970) do attempt tooffer some evidence for such an arid episode, and Meggers discussion of dating relies on thesesecondary sources for documentation (e.g., Meggers 1977:291).Many problems become apparent when such an episode is postulated for the Holocene ofAmazonia. Foremost is the question of timing: when is this episode supposed to have occurred? Aswill be shown, Meggers choice of bracketing dates is extremely arbitrary, given even the scarceand contradictory evidence available. Second, Meggers discussion (like Haffer 1974 and Muller1973) does not include any modern or critical perspective on the atmospheric mechanisms in-volved in the climate of the region or the mechanisms involved in climate change for the region.Third, Meggers does not take into account the many questions raised by the postulated ecologicalRichardG.Whitten,AnthropologyProgram,SocialBehaviorDepartment,Universityof SouthDakota,Ver-million, SD 57069238
  • 3. COMMENTSON HOLOCENEREFUGIAINAMAZONIAFigure 1. Locations of postulated refugia (after Haffer 1969:Figure 5, copyright 1969 by the AmericanAssociation for the Advancement of Science; Meggers 1977:Figure 4).changes. There has yet to be a critical discussion of the likelihood of widespread savannas inAmazonias past or of just what climatological changes would be necessary to bring about such asuccession. Finally, recent work on the linguistics of the region calls into doubt the suggestedmigration pathways chosen by Meggers and concomitantly the very necessity of postulating theserefugia.DATING CLIMATICEPISODESOF THE HOLOCENEIN AMAZONIACompared with most other areas of the world, Amazonian South America is a climatologicalterra incognita. The nature and timing of Holocene episodes are only now being outlined. Thisdoes not mean, however, that an investigator may deal as he or she will with the area. There arealready certain constraints placed on the imagination by what is known concerning Holoceneclimate in areas peripheral to the region and by what is known concerning the nature of climatechange in general (Lamb 1966, 1970) and Amazonian climate change in particular (Sanchez andKutzbach 1974).Meggers has stated that Amazonia underwent an arid episode during the period 4000-2000B.P.; as will be shown, it is not at all certain why these particular dates were chosen. By workingback through the documentation for the presence of this episode, it can be demonstrated that theinvestigators upon whom Meggers depends (particularly Muller 1973) have severelymisunderstood the evidence necessary for postulating such an episode.Meggers (1977) and Muller (1973) depend (in part) on a discussion of mean sea level (MSL)changes offered by Fairbridge (1960, 1962) for dating the arid episode. The difficulties inherent inunderstanding MSL changes as climatic indicators have been outlined by Flint (1971:322-329).Flint makes particular reference to the worldwide data gathered by Fairbridge (1962:Figure 7).More recent work conducted by Milliman and Emery (1968) places Fairbridges model in somedoubt. Milliman and Emerys model of MSL changes does not include the many fluctuations uti-239Whitten]
  • 4. AMERICAN ANTIQUITYlized by Muller in describing a Holocene arid episode (Milliman and Emery 1968:Figures 1 and 2;Fairbridge 1962:Figure 7; Muller 1973:Figure 99).Whatever the value of Fairbridges climate chronology, it is not certain whether Mullers use ofit to suggest an arid episode during the period 5000-2300 B.P. is a proper one. Unfortunately, ac-cording to his own rendition of the Bigarella (1965) and Fairbridge (1962) MSL change diagram(Muller 1973:Figure 99), this "arid" episode contains the diagrams highest recorded MSL, that is,the "wettest" phase in the Holocene. This date and wet phase (ca. 3800 B.P.) are also includedwithin Meggers postulated arid episode. The end date chosen by Muller and important for Meg-gers (1977:291) is 2300 ? 220 B.P., or 350 B.C. (Muller 1973:187). The date is attributed to Hurt(1964); actually, the correct date of 2675 i 150 B.P., or 725 B.C., may be found in Hurt (1964:32).This date is not given as the beginning of te local episode alled the SubmergenciaParanaguaense, as Muller believes, but rather as a date for the Abrouhos High contained withinthat episode (Hurt 1964:32).Even granting the acceptance of MSL studies as good indicators of gross climatic changeworldwide, Muller and Meggers arid episode cannot now be considered acceptable. Fairbridge(1976) has since continued his work on sea-level changes in Brazil with Hurt (1974) and has of-fered his own view of climatic episodes for Brazils Holocene. This chronology includes Period V,3400-2600 B.P. (1976:358), as a "cool and dry" episode, somewhat in conformity with Meggersprediction. However, Fairbridge also postulates "cool and dry" episodes for Period III,4800-4100 B.P., and Period VI, 2600-2000 B.P. (1976:357-358). This periodization in no wayagrees with the chronologies suggested by Muller and Meggers. Even if Period V were understoodto correspond to Meggers arid episode, it would still be necessary to explain away the previousand succeeding "cool and dry" episodes, since Meggers and Muller argue for only a singleHolocene arid episode.A second form of evidence incorporated by Meggers in the dating of the arid episode ispalynological. Climatic discontinuities may be analyzed through well-dated changes in the pollenregime. Palynological research would also seem to be an ideal way to test the refugia hypothesis,since the theory does rest upon fluctuating boundaries between forest and savanna. Forest pollenmay be distinguished from savanna pollen types, and such changes in the pollen regime aredatable (e.g., Van der Hammen and Gonzalez 1960; Wijmstra and Van der Hammen 1966). Thebest summary and discussion of palynological studies for northern South America is in Van derHammen (1975).It should be kept in mind that pollen studies in the tropics can be problematic. Differentialdisintegration of pollen grains due to extremes in temperature and precipitation is one concern(Faegri and Iverson 1964). A second concern lies with savanna ecology (discussed in greaterdetail below): savannas are often artifacts of mans interference with the landscape or the resultof changes in local hydrology. Climate changes are not always wise deductions from an influx ofsavanna-type pollen grains (see Hills and Randall 1968).Van der Hammen discusses several pollen cores that include dated material relevant to theHolocene and utilized by Meggers (1977:291). The cores have all been taken from areasperipheral to Amazonia (eastern Colombia, Guyana, and west-central Brazil). Thus the particularchanges in pollen regime are not analogous to the kinds of ecological changes that may have oc-curred in Amazonia. The climate is not uniform over so large an area (Ratisbona 1976; Snow1976; Trewartha 1961). The timing of the discontinuities could be thought of as roughly syn-chronous, however, if the carbon dates were consistent among themselves.In eastern Colombia, Van der Hammen reports on two pollen cores with dates attached. Onecore is from Lago de Bobos in the Paramo de Guantiva, on the western slope and within the An-dean rainshadow (Cordillera Oriental). Vegetation change in this area would not be analogous tochanges on the eastern slope. Van der Hammen reports an influx of paramo-type pollen at approx-imately 3000 B.P. This cool period probably lasted until approximately 800 B.P. The beginning andend of the period are dated by carbon-14 samples (Van der Hammen 1975:13-15, Figure 12). Itshould be noted that the close of the cool period does not fall at 1990 B.P. as Meggers reports(1977:291). Meggers has depended on a secondary source (Vanzolini 1970:41-42), who in turn240 [Vol.44, No.2,1979
  • 5. COMMENTSON HOLOCENEREFUGIAINAMAZONIAdepends on an earlier publication of Van der Hammen (1962). Van der Hammens publication ofthe original pollen diagram (1975:Figure 12) makes clear the suitability of the 800 B.P. end date.A second core (this time from the eastern slopes of the Andes) from Colombia was taken fromthe Laguna de Agua Sucia, south of San Martin. Here Van der Hammen reports "a major periodof open savanna, apparently drier than today, which lasted from 6-5000 B.P. to 3800 B.P."(1975:23). Neither of these disruptions is indicative of Meggers postulated 4000-2000 B.P. aridepisode. Only the second core could have any relevance to Amazonian vegetation change in anycase.In Guyana, Van der Hammen reports on a core taken from Lake Moreiru in the Rupununi savan-na. Here only a single change is noted: savanna pollen begins to dominate ca. 7300 B.P. and con-tinues until the present (1975:21-23, Figure 21). Again there is no evidence for a 4000-2000 B.P.episode, although Meggers (1977:291) does seem to list these cores as evidence. ParentheticallyVan der Hammen does not recognize mans influence (probably prehistoric) on the Rupununisavanna, although this has been suggested by Hills (1976).Finally, in west-central Brazil, Van der Hammen reports on samples taken from near Rondonia.There are no absolute dates reported for these cores. Van der Hammen states: "withoutreasonable doubt, that there were periods duing the Pleistocene when savannas locally replacedpart of the forest" (1975:25, emphasis mine). This is good news for those who, like Haffer, stressthe possibility of refugia during the Pleistocene; however, it cannot be used to indicate aridepisodes during the Holocene, as Meggers seems to believe (1977:291). In his original report onthis material, Van der Hammen reached the same conclusion on the relevance of this informationfor Pleistocene climates (1972:643).Palynological research fails to substantiate Meggers postulated arid episode. A review ofavailable MSL data has also failed. The absolute dates associated with changes in the pollenregimes are neither numerous enough nor consistent enough to suggest the presence of such anepisode at this time. In fact there is not a single date that can, under close examination, be used assupport for the arid episode.MECHANISMS FOR CLIMATICCHANGEIN THE AMAZON BASINThe one error that all the proponents of refugia in Amazonia make is to assume that climaticchange (if and when it did occur) was uniform throughout the region. That is, they assume that theoccurrence of an arid episode signifies a uniformly decreased mean annual precipitation over theentire region. Haffer depends upon this assumption to locate his refugia within Amazonia(1974:144). His own assumption is that:.. duringdryphases rainfallin areas of currentmaximaof precipitationremainedhighenoughto permitthecontinuedgrowthof forests,whiletheforestsprobablydisappearedfromtheinterveningareas oflowerrainfall (Haffer 1974:144).Haffers justification for this assumption seems to be his belief that orographic features ofAmazonia are the primary determinant of the regions precipitation regime; since the orographicfeatures have not changed, the distribution of precipitation in Amazonia has not changed either;only the amounts have changed (1974:144). Meggers accepts the locations of Haffers Pleistocenerefugia as the locations for her own arid Holocene episode (1977:Figure 4). Meggers does not offerany discussion of the regions climatology; so one must assume that she also accepts Haffers un-derstanding of Amazonian climatology.The climate of Amazonia is not uniform. Changes do not occur in such a manner that a drop inmean annual precipitation at Belem of, say, 25 mm is concurrent with a similar decrease atManaus. Teleconnections within the region and between Amazonia and other regions do exist(Bjerknes 1969; Namias 1972; Sanchez and Kutzbach 1974; Wyrkti 1973), but uniform changes ofthe sort Haffer asserts do not exist and, indeed, cannot exist. A brief description of climaticfeatures for the region is necessary to make this point clear.The climate of northern South America may be understood as the result of changes in the cir-culation of the planets atmosphere in conjunction with topography and radiation budget for any241Whitten]
  • 6. AMERICANANTIQUITYsingle area (Lamb 1966, 1970; Trewartha 1961; Ratisbona 1976; Snow 1976). The IntertropicalConvergence Zone (ITCZ)is seen as the climatic equator, the fluctuating meeting place of thenorthern and southern hemispheres circulatory systems. Its position is seasonally variable, butnorth and south movement west of the Andes is limited to approximately 5?-7? north latitude(Trewartha 1961:15), although recently the ITCZ has been seen as more variable in position(Flohn 1969:Figure 43). The ITCZs stability west of the Andes can be understood in terms of theintensity and position of the South Pacific Subtropical High. This cell remains quite constant, onlyoccasionally shifting position or varying in intensity (Hare 1966:Chapter 8). When a change doesoccur, the ITCZmoves south to northern Peru, causing the meteorological discontinuity known asEl Nino years.East of the Andes, the ITCZexhibits much more variation in its seasonal movements (Kendrew1961; Trewartha 1961:Figure 1.18; Ratisbona 1976:Figure 2). The movement of the ITCZis gener-ally southward over the Amazon Basin from November to March and generally northward (to theCaribbean coast) from December to May (Flohn 1969; Hare 1966: Schwerdtfeger 1976; Barrett1974). The South Atlantic Subtropical High pressure cell fluctuates in intensity and position insynchrony with these movements (see Figure 2).The precipitation figures for this region used by Haffer are the result of precipitation broughtinto Amazonia by the ITCZduring the period 1931-1960 (Reinke 1962). The tropical vegetation ofthe region is a result of the presence of year-round equatorial air (the ITCZ)and maritime tropicalair (the prevailing easterlies), both in conjunction with local soils, hydrology, topography, radia-tion budget, and the regions ubiquitous nonlineal convective precipitation. Vegetation and pre-cipitation on the eastern flanks of the Andes are also determined by altitude (Drewes and Drewes1957; Beals 1969). One peculiarity in the ITCZsbehavior takes place over the horn of Brazil, thenortheast region. Because the region is almost always under the influence of the South AtlanticSubtropical High and the ITCZpasses over only occasionally, less precipitation is received, andthe characteristic vegetation is caatingas (dry scrub forest and low brush) (James 1969:722).The preceding descriptions are based on data gathered before 1960. This is the "normative"understanding of the regions climate. For example, the most acceptable precipitation distributionmaps are based on 30-year means: 1931-1960 (Reinke 1962). The worldwide atmospheric circula-Figure 2. Normal movements of Intertropical Convergence Zone (ITCZ)over South America (approx-imate) (after Trewartha 1961:Figure 1.18, copyright 1961 by the University of Wisconsin).[Vol. 44, No. 2,1979242
  • 7. COMMENTSON HOLOCENEREFUGIAINAMAZONIAtion system exhibited severely anomalous behavior in the decade 1961-1970. Such anomalousbehavior gives the paleoclimatologist an opportunity to view the nature and effects of alternative,probably prehistoric climatic episodes (Bryson 1974). Although the past climates of Amazoniacannot be understood as of either one type or the other (that is, still other alternative climatic pat-terns are possible besides the 1931-1960 and 1961-1970 patterns), an examination of certainconditions in the last decade is constructive for an understanding of the likelihood of refugia.The last decade has been characterized by, first, a decrease in the intensity of the South PacificHigh Pressure cell. This has allowed the ITCZwest of the Andes to drop south and has resulted ina greater frequency of El Nino years for coastal Peru. Second, there have been an increase in theintensity of the South Atlantic High Pressure cell and changes in the intensity of the North Atlan-tic High Pressure cell. The southward trend of the ITCZ over the Amazon Basin seems to havebeen affected: the area has received markedly less precipitation. A bend in the ITCZhas occurredsuch that it has been moving over the northeast region of Brazil more frequently, and the areareports an increase of ca. 10% in mean annual precipitation. The east side of the Andes,however, is receiving ca. 10-20% less precipitation (see Figure 3) since the ITCZ fails to passthrough as frequently (Namias 1972; Sanchez and Kutzbach 1974; Bryson 1975; and personal in-vestigation of ESSA satellite photographs available at the Center for Climatic Research, Universi-ty of Wisconsin).Sanchez and Kutzbach (1974) have mapped the mean annual precipitation departures for1961-1970 (Figure 4). The central portion of Amazonia and the eastern slopes of the Andes areconsidered to have received approximately 10% less precipitation. The northeast region is seenas having received approximately 10% more precipitation. Sanchez and Kutzbach admit to a lowFigure 3. Postulated abnormal movement of Intertropical Convergence Zone (ITCZ)over South America(1961-1970).Whitten] 243
  • 8. AMERICAN ANTIQUITYFigure 4. Amazonian precipitation: departures of 1961-1970 mean annual precipitation from the1931-1960 mean (after Sanchez and Kutzbach 1974:Figure 1, copyright 1974 by the University ofWashington).density of reporting ground stations but maintain that this pattern is representative of climateduring the Little Ice Age.Overlaying Haffers postulated refugia locations with this arid episode pattern brings in-teresting results (Figure 5): refugia disappear in the central region and shrink on the easternslopes of the Andes, and new refugia of some sort appear in the northeast region of Brazil. Theseareas of decreased precipitation would not necessarily have become savanna, although a vegeta-tional response of some kind might be expected-particularly if the departures were greatenough to pass a certain threshold (see Hills and Randall 1968:2 and below).The little information that does exist on the paleoclimate and the mechanisms for climatechange in the region argues against the refugia locations that Haffer and Meggers have chosen.Although this does not negate all possibilities for refugia in Amazonias past, Haffers justifica-tions for the locations are not sufficient. The major orographic features of the Amazonian regionhave remained constant; such features, however, are only one determinant among many of theclimate of the region. It is in fact the changes in these other, atmospheric features that accountfor and cause climatic change in the region.VEGETATIONALCHANGESAND SAVANNA ECOLOGYUtilizing changes in mean annual precipitation to predict resultant floral communities, as Haf-[Vol. 44, No. 2,1979244
  • 9. COMMENTSON HOLOCENEREFUGIAINAMAZONIAFigure 5. Comparison of suggested refugia locations with precipitation departures (after Haffer1969:Figure 5, copyright 1969 by the American Association for the Advancement of Science; Sanchez andKutzbach 1974:Figure 1, copyright 1974 by the University of Washington).fer and Meggers have attempted, is always very dangerous. This is particularly so in the case ofsavanna ecologies. Vegetation responds not only to mean annual precipitation but also to thedistribution of that precipitation throughout the year, the radiation budget, the local hydrology,and the local soils. Mans interference with the landscape is also a very important aspect ofsavanna ecology.Meggers predicts the succession of a natural grassland savanna as a result of a decrease inAmazonias annual precipitation. There are, however, many ways for a savanna to come about,and in fact a decrease in precipitation is not alone sufficient. Natural savannas in the tropicsresult from the influence of seasonal extremes in soil moisture, including inundation. For northerntropical South America the conditions have been described as "unfavorable drainageconditions ... with alternating periods of waterlogging and desiccation" (Beard 1953:203). Forestwill not grow under such conditions because few woody species are adapted to these extremes.Until Meggers can provide information on the seasonal variability of precipitation or evidence fordrastic changes in Amazonias hydrology, no strong prediction of a savanna ecosystem successioncan be made (for a discussion of the ecology of natural savannas, see Hills and Randall 1968;Walter 1973:67-71).The fact that natural savannas depend on seasonal changes in soil moisture for their existencemakes palynological studies of their succession a problem. Most pollen cores are taken from lake245Whitten].V
  • 10. AMERICAN ANTIQUITYbottoms or marshy areas. These are areas where savannas are likely to be of hydrological origin,a result of seasonal flooding. Thus changes in hydrology rather than climate can explain somesavanna growth (Denevan 1968:45-47; Peeters 1968:27).Mans interference with the landscape can also result in a savanna succession. Man mayperiodically burn off the woody plants (for any number of reasons), introduce grazing animals, ortamper with the areas hydrology, all of which can help bring about the growth and maintenanceof a savanna. These savannas are "artificial," or artifacts of mans behavior, and do not dependon climate changes for their existence. Such savannas are widespread in the Old World, andevidence is growing that man has also played a crucial role in the origin, maintenance, andgrowth of savannas in the New World (e.g., on the role of mans interference in the ecology of theRupununi savanna in Guyana, see Hills 1976:11-29).Neither Meggers nor Haffer has discussed the ecology of the postulated tropical forestreserves: the refugia. Arguing against the feasibility of the Brazilian plan for forest reserves incontemporary Amazonia, Gomez-Pompa has stated his belief that such reserves are not largeenough to sustain tropical forest floral and faunal communities (Gomez-Pompa et al. 1972).Similarly it can be argued that the small refugia posited by Haffer and Meggers could not long beself-sustaining. The ability of these forest communities to resucceed the savannas is taken forgranted; actually, changes in soil texture and soil structure in the interim could militate againstthis possibility.Rather than a savanna ecosystem, a decrease in mean annual precipitation for Amazonia canguarantee only a shift in forest type. From the current Tropical Moist Forest (2,000-4,000 mm ofannual precipitation), two other forest types could succeed: Tropical Dry Forest (1,000-2,000 mmof precipitation annually) or Tropical Very Dry Forest (500-1,000 mm of precipitation annually).A Tropical Very Dry Forest is made up of deciduous trees, but with a lower biomass than the"rain forest" proper. It is easily cleared by man to form a savanna grassland. A Very DryTropical Forest is more open, and grasses may occur. Trees are low and have wide crowns. Againman may interfere to help form a savanna grassland. Both these drier tropical forests are evidentin South America; and either of them is an appropriate succession to the contemporary Amazo-nian forest under conditions of decreased mean annual precipitation (Hills and Randall 1968:2).Predicting the succession of natural savanna from a tropical forest climax under stress fromdecreased precipitation is a very risky endeavor, and no such savanna growth can be posited untilmuch more paleoecological evidence has been gathered.LINGUISTICDIVERSITYIN AMAZONIAMeggers purpose in postulating an arid episode with refugia at 4000-2000 B.P. is, I believe, theestablishment of an explanatory model for the linguistic diversity apparent in Amazonia. Even ifsuch an arid episode is acceptable (and the episode remains without much strong evidence thusfar), it can be shown that Meggers postulation of the linguistic history of the region is not the onlyone, or even the most preferable one. Any reconstruction of language changes for the area mustbe based on glottochronological methods, which, although controversial (see Bergland and Vogt1962; Hymes 1960), will be utilized here to make certain points. Critical readers should keepGirards caveat in mind when reviewing any discussion of languages in Amazonia:While manylinguistshave showna penchantfor classificationof SouthAmericanlanguages,attemptstobase classificationon concrete evidencehave been met with considerableresistance (Girard1971:1).Meggers explanation of the linguistic diversity of Amazonia begins first with her assumption ofthe breakup of the Ge-Pano-Carib language group at ca. 10,000 B.P. The existence of the Ge-Pano-Carib language was suggested by Greenberg (1960) and is accepted by the World Language List(Voegelin and Voegelin 1965:42,147-148). Nevertheless, it is a highly tentative Ursprache and notwithout its critics (see, e.g., Girard 1971:173). I was unable to discover any evidence that thislanguage underwent divergences ca. 10,000 years ago, as Meggers (1977:294) suggests.If I understand her methodology correctly, she has overlaid a map of the contemporary distribu-[Vol. 44, No. 2,1979246
  • 11. COMMENTSON HOLOCENEREFUGIAINAMAZONIAtion of language groups descended from the hypothetical Ge-Pano-Carib family with a refugiadistribution map from Haffer (1969:Figure 5). The result (1977:Figure 7) is claimed to support thelogic of certain migrations. Her distribution of contemporary speakers is based on Mason (1950),whereas more recent work would suggest that modifications are in order (see, for instance, Stark1977:48-54). This highly tentative reconstruction assumes the linguistic and temporal priority ofa refugium in the southeastern part of Amazonia. It could equally well be argued on the sameevidence, or lack of it, that the direction of migration be reversed. In fact Meggers cites noevidence to prove the northward direction of migration, nor does she discuss the difficulty orlikelihood of such migrations as opposed to migrations along rivers.Meggers next attempted correlation between linguistics and climatic discontinuities does in-volve her postulated arid episode. Noble (1965:107) has suggested divergences for the Proto-Arawakan languages at approximately 5000 B.P. Rodrigues (1958:684) has suggested divergencesin the Tupian family at the same date. As Meggers admits: "the correlation appears poor"(1977:297) between these dates and her postulated episode of 4000-2000 B.P. She suggests thatthose dates chosen by Muller (1973) for an arid episode (5000-2300 B.P.) may be correct after all,although she retains her original estimate on the accompanying diagram (1977:Figure 9).In order to include these linguistic discontinuities within her episode, Meggers next suggeststhat these divergences may have occurred within the postulated episode if the rate of languagechange has not remained constant in the past, that is, if the 5000 B.P. date has been erroneouslycomputed (Meggers 1977:297). This, however, goes against the fundamental assumption of glot-tochronology, and certainly no dates can be admissible as evidence for prehistory unless theassumption of a constant rate of change is consistently accepted.It should be noted here that Nobles (1965) work has been partially invalidated by recent workon Uru-Chipayan by Olsen (1964, 1965; see also Voegelin and Voegelin 1965:11). This work sug-gests that Uru-Chipayan has affinities with Mayan, not Arawakan, and throws into doubt Noblesreconstruction of Proto-Uruan. It also discredits Nobles postulated homeland for Proto-Arawakan. This is in accord with Lathraps arguments against southeastern Peru as the Ursitzfor Arawakan dispersal (1970:70-77). In any case, Meggers assertion that these two languagesshare a common homeland in southeastern Peru is also in doubt since, according to Rodrigues(1958:683), the origins for the Tupi family may be found in the Rio Guapore region.More recent work, superseding that of Noble and Rodrigues, describes a different pattern oftime and dispersal for language groups in the region. Stark (1977) has recently completed alengthy revision and reappraisal of Amazonian linguistic history. Her results appear to be con-gruent with Lathraps (1970) suggestions concerning prehistoric population movements based onarchaeological evidence.Starks own glottochronological reckoning describes a divergence of Proto-Arawakan and Tupi-Guaranian at approximately 3730 B.P., similar to the dates offered by Noble and Rodrigues. Thecenter of dispersal chosen by Stark, however, is not similar. Stark postulates a center south of theAmazon River, between the Tapajos and Madeira rivers (Stark 1977:7). This is not an areapostulated as an arid episode refugium by either Meggers (1977:Figure 4) or Haffer (1969:Figure5). As Stark reconstructs the events, Proto-Arawakan diverged at this time, and a northwardmigration occurred along the Rio Negro (1977:7). Consequent divergences from these twolanguage stocks are further outlined by Stark as occurring in "waves"; the migration paths areseen as primarily along waterways (again, these conclusions are in agreement with Lathraps re-construction).Starks reconstruction is complex, but complete and consistent. No assumed paleoecologicaldiscontinuities of mammoth proportions need be called upon, deus ex machina, to explain thediversity and locations of Amazonian languages if reconstructions like Starks are correct. Mi-gration pathways along watercourses are preferable to Meggers paths, if only because ofwhat is known of ethnographic evidence on this problem. Migrations along waterways not onlyare easier but also agree with what is known of the contemporary Indian understanding of riversettlement and social prestige. For example, Goldman (1963) has described ethnographic ex-amples of such minimigrations for the Cubeo.Whitten] 247
  • 12. AMERICAN ANTIQUITYCONCLUSIONSIn the preceding discussion, I have attempted to criticize, in as organized a manner as possible,the hypothesis of Holocene refugia in Amazonia. Meggers has stated (in what may, after all, be amisprint): "It is unlikely that environmental changes of the magnitude inferred by biologists wouldhave affected human beings" (1977:287). I agree; it is unlikely if only because at this time it is alsohighly unlikely that the inferences are correct ones for the Holocene ecology of the Amazonianregion. Any such environmental changes have yet to be documented. Arguments against thepresence of refugia during an arid episode can be summarized in this manner:1. Evidence for dating such an episode from mean sea level studies is equivocal. The originalperiodization by Muller and Meggers is rather arbitrary. More recent MSL studies would suggestthe presence of oscillations undiscussed by Meggers.2. Palynological evidence does not support the proposed dates for such an episode. Whereasthere is a possibility that one sample suggests forest remission (Rondonia), this probably occurredduring the Pleistocene, not the Holocene as Meggers seems to believe.3. The most recent information on climate change in Amazonia argues against the kind ofuniform changes Meggers assumes. Work on alternative climates for the region would suggestthat a redistribution of the postulated refugia is necessary (if they ever existed).4. There needs to be a critical discussion of the exact kinds of climate and hydrologynecessary for the natural genesis of savannas. Otherwise this ecosystem cannot be accepted apriori as an alternative to tropical forest during "arid" episodes.5. Evidence for the linguistic history of the region argues against the necessity for postulatingsuch refugia and any migrations from, around, or into them. Ethnographic evidence arguesagainst such refugia migrations ever having been a popular Amazonian pastime.Rather than accept Lathraps (1970) reconstruction of Amazonian prehistory, Meggers has at-tempted to utilize Haffers model as an alternative explanation. Actually there is very little purelyarchaeological evidence in the region against which to test either theory.The best explanations are those that have a certain sense of satisfyingness about them and can-not be demonstrated to be wrong (Ghent 1962a1962a,1962b, 1963). If Haffers assumptions about theclimate and ecology of Amazonia were more realistic, this would make Meggers adaptation ofkeen interest to prehistorians. If Meggers own work concerning dating and linguistics in theregion were built on a more solid foundation, the attempt would be ingenious and laudatory. Un-fortunately, as this review has attempted to demonstrate, such does not appear to be the case.Lathraps (1970) reconstruction still stands as th re satisfying explanation for the prehistoryof Amazonia.Acknowledgments. Several individuals have given of their time and patience during the construction ofthis essay. I wish to thank Dr. Donald Thompson (archaeology), Dr. Louisa Stark (linguistics), Dr. WilliamDenevan (savanna ecology), Dr. J. Kutzbach (climatology), and Mr. Kent Mathewson (cartography), all at theUniversity of Wisconsin. At the University of Illinois, I wish to thank Dr. Wayne Wendland (climatology). Allerrors in information and judgment nevertheless remain my responsibility. This essay represents Contribution2 of the South Park Street Geographical Society.REFERENCESCITEDBarrett, E.1974 Climatology from satellites. Methuen, London.Beals, E.1969 Vegetational change along altitudinal gradients. Science 165:981-985.Beard,J.1953 The savanna vegetation of northern South America. Ecological Monographs 23(2):149-215.Bergland, K., and H. Vogt1962 On the validity of glottochronology. Current Anthropology 3:115-153.Bigarella, J.1965 Subsidios para o estudo das variacoes de nival oceanico no quaternario brasiliero. Anais da Aca-demia Brasiliera de Ciencias 37:263-278 (Supp.).248 [Vol. 44, No. 2,1979
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