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Quaternary International 249 (2012) 43e52

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Quaternary International

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Late pre-Columbian agroforestry in the tropical lowlands of western Ecuador

Peter W. Stahl a,*, Deborah M. Pearsall b

aDepartment of Anthropology, Binghamton University, Binghamton, NY 13902-6000, USAbDepartment of Anthropology, University of Missouri, Columbia, MO 65211, USA

a r t i c l e i n f o

Article history:Available online 10 May 2011

* Corresponding author. Fax: þ1 607 777 2477.E-mail addresses: pstahl@binghamton.edu (P.W. S

(D.M. Pearsall).

1040-6182/$ e see front matter � 2011 Elsevier Ltd adoi:10.1016/j.quaint.2011.04.034

a b s t r a c t

Archaeobiological data are used to explore the agricultural basis of the Jama-Coaque II archaeologicalculture that inhabited the western coastal lowlands of Ecuador between approximately AD 400 and AD1430. Analyses of archaeobotanical and archaeofaunal assemblages recovered from 14 archaeologicalsites throughout the valley implicate an extensive native agroforestry system. The quantitative andqualitative composition of assemblage diversity suggest the accumulation and deposition of restrictedcategories of plants and animals whose ecologies reveal the possibility of a landscape managed througha form of pre-Columbian agroforestry that combined domesticated annuals, perennial tree crops, anduseful forest taxa.

� 2011 Elsevier Ltd and INQUA. All rights reserved.

1. Introduction

The earliest documents dealingwithwestern SouthAmerica onlybriefly mention lands that lay between the Spanish colonial base inPanama and the prized treasures that lured conquistadores south toPeru. In AD 1531, during his third exploratory trip, Francisco Pizarropassed through Ecuador’s northern Manabí coast and described theindigenous towns of Pasao (Aranpaxos, possibly Cabo Pasado) andCoaque in which he resided for several months (Fig. 1). These verydifferent settlements may have represented indigenous expressionsof inter-ethnic conflicts that were simultaneously unfolding duringthe fateful years of early European conquest. Archeology indicatesthat this brief historic snapshot barely captured a coastal glimpse ofthe large, dense, and politically centralized regional populations thatlay toward the interior. Shortly after their first mention, thesecultures were staggered by the brutal impact of exotic diseases, fol-lowed by depredations at the hands of invading Europeans, invasionby other native groups, and eventual domination by African leaderswhofirst appeared on the coast asmarooned slaves.Within less thana century, the native pre-Columbian cultures of this area had dis-appeared forever (Zeidler, 2003).

A protracted program of interdisciplinary archaeological inves-tigations undertaken throughout the Jama River Valley in northernManabí province has documented a long pre-Columbian culturalsequence based upon an inventory of 239 archaeological sites,

tahl), pearsalld@missouri.edu

nd INQUA. All rights reserved.

located and tested during systematic regional survey of an approx-imately 785 km2 study area. Since its earliest known human occu-pation just prior to 2000 BC, the valley has been occupied byfarmers. A continuous sequence of human occupation, intermit-tentlyand variably interrupted by three valley-widevolcanic events,reveals a protracted legacy of agriculturally-based settlement,terminating with the Jama-Coaque II culture which occupied thevalley up to its fateful encounter with Spanish invaders (Zeidler andPearsall, 1994; Zeidler et al., 1998). In the twilight centuries of itsexistence, native settlement in this lowlandvalleyofwestern coastalEcuadormayhave been dispersed between three small autonomouschiefdoms, each with a three-tiered site hierarchy dominated bya primate mound (Zeidler, 2005).

This paper explores the agricultural basis of this Jama-Coaque IIarchaeological culture, and suggests that it was at least in partestablished upon an extensive system of native agroforestry withina managed landscape that combined domesticated annuals alongwith perennial tree crops and useful forest taxa (Denevan, 2001:p.69). Evidence for this pre-Columbian productive system is basedupon analysis of archaeobiological specimens retrieved from 14archaeological sites distributed throughout the length of the valley.This presentation outlines some basic features of tropical agrofor-estry. It then introduces the Jama River Valley and its environmentalcontext, and briefly summarizes pertinent archaeological data. Itexplores various aspects of archaeobotanical and archaeofaunaldiversity within the studied samples by focusing on assemblagerichness, equitability, specimen ubiquity, and rank order abundance.The analysis of the recovered archaeobiological data indicates lowerthan expected richness, with specific kinds of plants and animalsdominating the assemblage profiles. Their respective ecologies

Fig. 1. Map of Northern Manabí province showing location of the Jama River drainage. Note the modern settlements of Coaque and Cabo Pasado which may be the sites of Coaqueand Pasao mentioned in early chronicles. Inset map shows location in Ecuador.

P.W. Stahl, D.M. Pearsall / Quaternary International 249 (2012) 43e5244

further reveal the possibility that the Jama Valley, at least by thistime, included a mosaic of fragmented forests suggestive of a land-scape managed through a form of pre-Columbian agroforestry.

2. Tropical agroforestry

Agroforestry is an old agricultural technique defined by signifi-cant long-term ecological and/or economic interaction between

deliberately spaced or sequentially combined woody forest peren-nials and agricultural plants/animals within the same productivesystem (Nair, 1989). Agroforestry has justifiably attracted enormousattention as an environmentally beneficial resource managementpractice for the conservation of tropical biodiversity. It can reducecurrent forest degradation through unsustainable practice, providesuitable habitat, and connect patches of natural habitat which arebuffered from poorly managed land use (Schroth et al., 2004).

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Agroforestry was likely widespread prehistorically throughoutthe neotropics. Current productive systems are highly diverse withrespect to their degree of management, scale of spatial andtemporal productivity, and use of different techniques. They canrange from intensively managed and species-rich house gardens topassively managed swidden fallows that are only occasionallyvisited in order to harvest useful plants and animals. In most cases,the focus of productive activity tends to be spatially and sequen-tially protracted, thus creating mosaic landscapes of variablymanaged patches in different phases of vegetative cover. Agrofor-estry supports varieties of plants and animals that differ in numberand kind from monocropping. The productive components ofagroforestry are incorporated through intentional and uninten-tional management or may persist as remnants of previous systems(Balée, 1994; Denevan, 2001).

High species diversity is a hallmark of forested tropical envi-ronments; it is a characteristic created by, and maintained through,intermediate levels of dynamic instability (Connell, 1978;Colinvaux, 1998). Highly productive agroforestry systems areoften characterized by increased biological richness whencompared to tracts of forest that were not recently farmed.Disturbances in the forest canopy constantly create opportunitiesfor numerous species that take advantage of naturally or culturallycreated gaps. As an instrument of disturbance, the agroforesterprotects useful forest perennials during garden preparation,constantly introduces desirable taxa throughout the life of thegarden, and continues to exploit usable plants and animals wellinto a fallow stage whose trajectory is often intentionally managed.During these later stages, fallow formations can accumulate taxa atsimilar rates to growth in high forests, yet can exceed them inspecies richness because of the significant input of culturally usefultaxa (Balée, 1994; Denevan, 2001).

3. The Jama Valley: present environment and archaeologicalpast

Measuring some 1612 km2, the Jama Valley is the largestdrainage basin in northern Manabí Province. Located just south ofthe equatorial line at 0� 00 15” S (Fig. 1), it is centered around the 75linear km main channel of the Jama River which flows from ca200masl near its headwater in the lowhills of the coastal cordillera,and dropping to sea level at its eventual embouchure with thePacific Ocean just north of the town of Jama. As it ascends throughrolling terrain the valley transitions between dryer to wetterconditions that support four different life zones based on altitudeand humidity. A Very Dry Tropical Forest zone with mean annualtemperatures between 24� and 26 �C supports deciduous forest andsavanna grasslands extending along the arid coastal strip to the1000 mm isoyet just north of Jama. From here, a subhumid DryTropical Zone extends up the coast with annual rainfall between1000 and 2000 mm and average annual temperatures between 24�

and 25 �C. Portions of the middle Jama Valley are characterized bycooler temperatures and a Dry Pre-Montane Forest zone above300m asl with annual rainfall amounts between 500 and 1000 mmappearing in two distinct seasons. Elevations above 300 m aslsupport a Humid Pre-Montane Forest zone between the 1000 and2000 mm isoyets where annual temperatures range between 18�

and 24 �C (Zeidler and Kennedy, 1994).The Semi-Arid Coastal Plain physiographic zone of the lower

valley includes a mangrove estuary at the river mouth, a thin stripof shoreline beach, extensive and deep alluvial floodplain, anddissected structural and erosional hills with elevations between100 and 200m asl (survey Stratum I). Moving upriver, the Jama cutsa deep gorge through the highly dissected landscape of the JamaNarrows or Sub-Humid Coastal Cordillera where hills range

between 300 and 600 m asl (Stratum II). The Semi-Humid andHumid Uplands of the middle and upper valley between 200 and500 m asl are defined by landscapes of alluvial floodplains,erosional valleys, and structural and erosional hills (Stratum III).Over the last century, logging, ranching, and intensive agriculturealtered the surrounding countryside into a patchwork of scatteredgrowth forest within a heavily agricultural landscape. Today, over93 percent of the valley contains non-forested land used for agri-culture and grazing, with the remainder comprising a mosaicpatchwork of secondary growth forests that is principally confinedto isolated ridgetops and slopes (Zeidler and Kennedy, 1994).

Probabilistic archaeological survey and vegetation samplingwere undertaken in three survey strata (Str. Ie III) corresponding tothese three physiographic zones in an approximately 785 km2 studyarea (Fig. 2). Archaeological reconnaissance and testing in the valleyreveal a lengthy, and occasionally interrupted, prehispanic humanoccupation that spanned over 3500 calendar years. A seven phasecultural sequence, based in part on 38 radiocarbon determinationsfrom 17 archaeological sites, and further supported by three superpositioned strata of volcanic airfall sediments, or tephras, isproposed for the area. Prehispanic settlement of riverinefloodplainsappears to have begun with an Early Formative Piquigua phase(Valdivia 8) occupation from 2030 to 1880 cal B.C.; however, it ispossible that earlier material may lie deeply buried in alluvialcontexts. Volcanic airfall (Tephra I) blanketed the valley during this150 year occupation, followed by human abandonment for reasonsprobably unrelated to volcanic activity around 1900 cal B.C. A 600year hiatus separates the earliest known occupation of the valleyfrom the subsequent Late Formative Tabuchila phase (Chorrera)reoccupation at 1300 cal B.C. This occupational phase was abruptlyterminated at 750 cal B.C. with the appearance of a second volcanicairfall (Tephra II). After 500 years the valley was again repopulatedwith the appearance of a new Muchique 1 phase of the RegionalDevelopment Jama-Coaque I ceramic tradition beginning at 240 calB.C. and ending at 90 cal A.D. The Jama-Coaque II tradition continuesafter the third volcanic airfall (Tephra III) which separates theMuchique 1 phase occupation from the subsequent Muchique 2phase beginning 420 cal A.D (Zeidler et al., 1998).

Thefinalpre-Columbianoccupationof thevalley isdefinedby thisJama-Coaque II tradition. During itsMuchique 2 and 3 phases, datingfrom roughly AD 400 to AD 1200, Jama-Coaque II may have beencharacterized by a three-tiered settlement hierarchy dominated bythe largest (>60 ha) sites, spaced roughly 15 km apart, a feature notuncommon for chiefdoms or early states. The valley at this timemayhave supported three small polities corresponding to their respectiveterritories in the lower andmiddle reachesof thevalley, eachmarkedby its own primate mound in a larger alluvial area, and possiblydominating smaller alluvial areas with secondary mounds in thesame valley segment. The Jama-Coaque II ceramic traditioncontinues with a Muchique phase 4 beginning at 1290 cal A.D. andending at 1430 cal A.D., followed by a poorly understood Muchiquephase 5 beginning at 1430 cal A.D. and ending at 1640 cal A.D. Theterminal phase occupation may be associated with the historicCampace who inhabited the area at the time of Spanish conquest(Zeidler et al., 1998; Zeidler, 2005; Zeidler and Zeidler, 2002).

4. Archaeobiological data from Jama-Coaque II contexts inthe Jama Valley

Archaeobotanical and archaeofaunal specimens were systemati-cally retrieved from a variety of depositional contexts distributedthroughout the length of the valley system. The assemblages con-sulted in this studyaremainly fromMuchique2/3 contexts thatweresuper positioned above the third major tephra fallout at 14 archae-ological sites (Fig. 2). These include 25,373 macrobotanical

Fig. 2. Map of the sampled area showing location of archaeological sites from which archaeobiological data were recovered and used in this study. Str. I-III designate three surveystrata that correspond to three physiographic zones throughout the valley. Inset map shows location of project area in Ecuador.

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specimens recovered from nine archaeological sites with Muchique2/3 contexts and one site with Muchique 4 contexts (M3B3-012 isamulticomponent sitewithcontexts frombothMuchique2/3 and4).A sample of 51,987 archaeofaunal specimens was retrieved from 13sites withMuchique 2/3 contexts and onewithMuchique 4 contexts(Table 1). Additional corroborating data are provided in the analysisof phytolith specimens extracted fromadeep, stratified soil profile atthe site of Río Grande M3D2-006 (Donahue and Harbert, 1994;Veintimilla, 1998, 2000). Similar contexts were also explored atother sites including Pechichal and San Isidro (Pearsall, 2004).

Table 1Archaeological sites with archaeobiological specimens in association with Jama-Coaque II contexts.

Designation Site name Archaeobotanicalsample

Archaeofaunalsample

M3B2-001 Don Juan 3998 28,435M3B3-001 La Mina 190M3B3-002 El Tape 9556 155M3B3-012 Acrópolis 558 107M3B3-029 Ladrillera 3M3B4-007 La Isla 207 409M3B4-011 Pechichal 8864 12,572M3D2-001 San Isidro 161 1329M3D2-006 Río Grande 6 263M3D2-009 Finca Cueva 1908 8039M3D2-056 Dislabón 105 478M3D2-082 Cuadros 3M3D2-091 Eloy Alfaro 10 2M3D2-123 Hcda. Paloma 2

Total 25,373 51,987

4.1. Assemblage accumulation, deposition, preservation, andrecovery

The studied samples were obtained through dry-screening ofdeposits in addition to uniform blanket sampling involving therecovery of constant volume soil samples from each natural andarbitrary excavation context and feature. Soil samples weresubsequently processed via water flotation using an IDOT system(Pearsall, 2004:p. 32). In certain instances, notably rich archaeo-logical deposits were opportunistically excavated and processed intheir entirety through water flotation. The systematic recovery ofspecimens via flotation strongly affected the quantitative andqualitative nature of the studied assemblages and influencesderived interpretations (Pearsall, 1995; Stahl, 1995). The samplesare dominated by small and often fragmented specimens, most ofwhich proved difficult to identify with any degree of taxonomicresolution. Fortuitously charred botanical specimens and certainstructurally dense diagnostic skeletal elements, particularly teethand otoliths, comprise the majority of specimens that could beidentified to lower taxonomic levels which might be useful forpaleoecological resolution.

It is important to consider that the studied assemblages wererecovered from archaeological contexts that sample a range ofdepositional settings which possibly involved very different modesof assemblage accumulation, deposition, burial, and preservation.Typical excavation units measured 2 � 2 m. Initial test units wereexcavated in arbitrary levels in order to reveal underlying stratig-raphy which could be used as a guide for subsequent excavationwhenwarranted. Many of the excavations were aimed at obtaininglong stratigraphic sequences from deep multicomponent occupa-tions for purposes of chronology building, and in the process likelysampled different depositional contexts. Settlement data suggest

P.W. Stahl, D.M. Pearsall / Quaternary International 249 (2012) 43e52 47

that later period archaeological sites throughout the valley systemwere organized in a three-tiered hierarchy based upon mound size.In these contexts, archaeological sampling often involved theexcavation of a series of test pits to uncover sequences of moundconstruction. Additionally, looter’s pits, and natural exposures,especially riverbank cuts, were cleaned and profiled in order toguide further stratigraphic excavation of fortuitous archaeologicaldiscoveries (Fig. 3).

The studied assemblages together represent a heterogeneousmix of accidentally and intentionally accumulated organic speci-mens that might have been deposited in the same feature contextor variably accumulated between different kinds of contexts. Forexample, one half of a large bell-shaped feature exposed in a rivercut (Fig. 3) was opportunistically sampled for its well-preservedspecimens. These included: accidentally entrapped local micro-faunas; animal prey specimens and plant macroremains that wereintentionally deposited by humans in the course of waste disposal;and, in situ and fluvially transported phytoliths (Stahl, 2000;Pearsall, 2004). Other archaeological contexts as midden, livingfloors, and caches are also likely represented in the studiedassemblages. Variability in excavation strategy, original specimenaccumulation, deposition, burial, and differential preservation areimportant factors influencing the uneven sample sizes available forstudy (Table 1). The numerous archaeobiological specimens thatwere deposited in various contexts throughout the length of thevalley system include a wide variety of plant and animal familiesthat were present during the later prehistoric Jama-Coaque IIoccupation. These include specimens from at least 25 botanicalfamilies identified from macroremains, and 42 vertebrate zoolog-ical families identified from preserved bone, teeth, and otoliths(Table 2).

The following sections explore certain paleoecological implica-tions of these data by focusing on the quantitative and qualitativecomposition of assemblage diversity within later prehistoricarchaeological contexts throughout the valley. Specifically, thenumbers of different kinds of specimen categories (richness) atlevels of taxonomic acuity that can contribute greater resolution for

Fig. 3. Deep test unit at Boca de Calada (Upper Left), Disturbance activity by Looters or Huaqprofile exposed in bank cut of the Río Cangrejo (Lower Right).

ecological inference are examined. Can significant trends inassemblage richness be detected at certain archaeological sites anddepositional contexts that might implicate specific kinds ofproductive systems present throughout the valley? Examination ofthe relative distribution of specimens within these categories(equitability or evenness) is conducted in order to identify anysignificant trends amongst site assemblages. Are certain siteassemblages characterized by relatively even (high equitability) oruneven (low equitability) distributions of specimens within cate-gories? Analysis then examines those taxa that contribute topatterning in assemblage diversity by examining their rank order interms of spatial ubiquity and numerical dominance in recoveredcontexts. Subsequent discussion is focused on cultural andecological implications of the archaeobiological data that contrib-uted to assemblage patterning during the late prehistoric Jama-Coaque II occupation of the Jama Valley.

4.2. Assemblage diversity: richness and equitability

Archaeobiological sample sizes vary widely (range ¼ 2 to28,435) between site contexts throughout the Jama Valley.Assemblage richness was examined using two techniques that aresensitive to the relationship between sample size and diversitymeasures (Grayson, 1981). Richness considers the results of rare-faction analyses (e.g. Raup, 1975; Tipper, 1979; Gotelli and Colwell,2001) that generate estimated richness values in smaller samplesizes through interpolation from larger samples, using a programdeveloped by Holland (2003) which is freely available on theinternet. These results were checked with a popular simulationapproach amongst archaeologists that extrapolates values frompooled smaller samples (Kintigh, 1992). Additionally, the Kintighsimulation program is used to explore evenness or equitability inrelation to the differing assemblage sample sizes. Each technique isassociated with its own assumptions and problems (e.g. Birks andLine, 1991; Gotelli and Colwell, 2001; Orton, 2000; Ringrose,1993), and they are used here to understand assemblage compo-sition for purposes of further data exploration.

ueros (Upper Right), Pechichal pit feature exposed in river cut (Lower Left), cleaned soil

Table 2Botanical (macroremain) and zoological families identified in Jama-Coaque IIcontexts.

Botanical family Common name Zoological name Common name

Cannaceae Canna Carcharhinidae Requiem SharksEuphorbiaceae Spurge Dasyatidae StingraysFabaceae Bean Ariidae Sea CatfishMarantaceae Arrowroot Ophididae BrotulasMalvaceae Cotton Serranidae GrouperPoaceae Grass Carangidae Jacks, PompanosCucurbitaceae Gourd, Squash Lutjanidae SnappersAnnonaceae Soursop Haemulidae GruntsArecaceae Palm Sciaenidae Croakers, DrumBignoniaceae Tree Gourd Scaridae ParrotfishBixaceae Achiote Sphyraenidae BarracudaLamiaceae Mint Bufonidae ToadMimosaceae Tree Legume Ranidae FrogMyrtaceae Guava Emydidae Pond TurtleSapotaceae Sapote Iguanidae IguanaAizoaceae Carpet Weed Boidae BoaAmaranthaceae Pigweed Crotalidae ViperAsteraceae Sunflower Tinamidae TinamouCommelinaceae Spiderwort Anatidae DuckLinaceae Flax Ardeidae Heron, BitternPassifloraceae Passion Fruit Accipitridae Eagle, HawkPhytolaccaceae Pokeweed Rallidae RailsPolygonaceae Knotweed Columbidae Pigeon, DoveRosaceae Rose Cuculidae CuckooSolanaceae Nightshade Didelphidae Opossum

Dasypodidae ArmadilloBradypodidae Tree SlothMyrmecophagidae Tree AnteaterCebidae MonkeySciuridae SquirrelMuridae Rat, MouseCaviidae Guinea PigAgoutidae PacaDasyproctidae AgoutiEchimyidae Spiny RatLeporidae RabbitPhyllostomidae BatCanidae DogFelidae CatProcyonidae RaccoonTayassuidae PeccaryCervidae Deer

Fig. 4. Rarefaction curves plotting Estimated Richness (Estimated S) and 95% confi-dence intervals with Sample Richness (Sample S) along sampling sizes by site forarchaeobotanical data.

Fig. 5. Rarefaction curves plotting Estimated Richness (Estimated S) and 95% confi-dence intervals with Sample Richness (Sample S) along sampling sizes by site forarchaeofaunal data.

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Rarefaction analyses for both archaeobotanical and archae-ofaunal assemblages indicate a trend toward lower than expectedrichness based upon respective sample size differences. Thearchaeobotanical data (Fig. 4) clearly demonstrate an overallpattern of depressed richness across most sites for which there aredata. This is supported in both rarefaction and simulation analyses,with the exception of sites characterized by very small sample sizes(which may be relatively meaningless) and the pit feature atPechichal, M3B4-011. The archaeofaunal data (Fig. 5) showa somewhat comparable trend toward depressed richness yet withsomewhat greater complexity. Higher than estimated richnessvalues are present at very small sampling intervals, and two sites(M3D2-001, M3D2-009) with larger sample sizes approach higherthan expected richness. These differences between the data setscan be explained by the nature of sampled contexts. Higherbotanical richness in combination with lower zoological richnesswithin a deep refuse pit can be explained by the intentional culturaldiscard of awide range of plantmaterial produced as a byproduct ofsubsistence activities (Pearsall, 2004). This appears in associationwith the accidental inclusion of a restricted range of local micro-faunas particularly susceptible to entrapment, alongside isolatedfragments of major dietary taxa (Stahl, 2000, 2006, 2008). Incontrast, the studied specimens from San Isidro and Finca Cuevawere recovered in excavations that sampled a variety of different

depositional contexts, particularly at the former site, which isa large and focal mound dominating the valley system. Thesepossible explanations are further explored below.

Simulation results using the program developed by Kintigh(1992) for estimating assemblage equitability or evenness areillustrated for the archaeobotanical (Fig. 6) and archaeofaunal

Fig. 6. Relationship between Equitability (Ordinate) and Sample Size (Abscissa) withplotted 90% Confidence Intervals for archaeobotanical data.

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(Fig. 7) assemblages. Both simulations are characterized by rela-tively low evenness (values approaching 1 indicate even distribu-tions of categories). A number of contexts fall below the 90%confidence interval for expected equitability or evenness valueswhen respective sample sizes are taken into consideration. Thearchaeofaunal data, in particular, show a trend toward very unevenrepresentation through domination by a restricted set of taxonomiccategories. With the exception of the pit feature, the larger samplescomprising the archaeobotanical data also demonstrate a tendencytoward lower than expected equitability values. Variations inequitability values can to some degree be explained by differencesin sampled depositional contexts.

Compared with other sites, a relatively richer set of botanicalsubsistence items in the pit tends to be more equitably distributedas a factor of waste disposal. Otherwise, both the archaeobotanicaland archaeofaunal data suggest a trend toward includinga restricted range of items (Low Richness) unevenly dominated bycertain categories (Low Equitability or Evenness) in variouscontexts throughout the valley. Examination of the distribution ofspecimens that comprise identified categories will explore theirspatial and numerical distributions within the sampled contexts,

Fig. 7. Relationship between Equitability (Ordinate) and Sample Size (Abscissa) withplotted 90% Confidence Intervals for archaeofaunal data.

allowing evaluation of whether or not a redundant set of categoriescan be identified as contributing to low assemblage richness andequitability or evenness.

4.3. Assemblage distribution: specimen ubiquity and numericalabundance

Archaeobotanical categories are arranged in a simple rankordering based on their ubiquity at archaeological sites (n ¼ 10) andwithin sampled archaeological contexts (n ¼ 118) at these sites(Table 3). The 15 top ranked items in both lists feature a strongpositive and significant correlation (rs ¼ 0.85, p < .001), suggestingthat a highly similar set of categories is ubiquitous both betweenarchaeological sites and within sampled contexts. The rank order ofnumerical abundance between sites andwithin sample contexts alsoappears to be similarly correlated, albeit in a weaker way (rs ¼ 0.68,p ¼ .005), suggesting that a comparable ordering of botanical taxadominates the numerical profile of recovered and identified botan-ical categories. The greatest variation between rank lists is amongstcertain taxa that are relatively ubiquitous yet not highly abundant(e.g., Sida, Fabaceae, Poaceae, Passiflora), or in other words, theyappear as relatively isolated finds throughout many contexts.

Archaeofaunal genera are similarly arranged in a simple rankordering based on their ubiquity at archaeological sites (n¼ 11) andwithin sampled archaeological contexts (n ¼ 166) at these sites(Table 4). The 15 top ranked items in these lists are also positivelyand significantly correlated (rs ¼ 0.68, p ¼ .005), suggesting thatlike their botanical counterparts, a similar set of categories areubiquitous both between archaeological sites and within sampledcontexts. The rank order of numerical abundance between sites andwithin sample contexts features a strong positive and significantcorrelation, (rs ¼ 0.93, p < .001), suggesting that a very similarordering of vertebrate taxa dominate the numerical profile ofrecovered and identified faunal categories. Here, the greatestvariation between rank lists is amongst certain taxa that tend to beless abundant than they are ubiquitous (e.g., Odocoileus, Mazama,Alouatta, Tayassu), and may appear as relatively isolated findsthroughout many contexts.

In both data sets, the major taxonomic categories thatcontribute highest ubiquity within sites and individual excavationcontexts also tend to be positively and significantly correlated withthose that are found in highest abundance. Taken together, theseanalyses strongly point toward the accumulation and deposition ofrestricted plant and animal categories that also numericallydominate studied contexts at this time throughout the valley. The

Table 3Archaeobotanical data: rank order of top 15 macrobotanical categories according toubiquity and abundance by site (S) and individual excavation context (C). (%) recordspercentage ubiquity by site and context (rounded calculations).

Taxon Ubiquity (S) Ubiquity (C) Abundance (S) Abundance (C)

Wood 1 (100%) 1 (97%) 1 1Zea mays 2 (100%) 2 (80%) 2 2Linum 3 (60%) 7 (22%) 6 3Solanaceae 3 (60%) 6 (24%) 8 4Phaseolus 5 (50%) 4 (31%) 4 4Trianthema 5 (50%) 3 (43%) 3 6Sideroxylon 5 (50%) 5 (25%) 5 8Sida 8 (40%) 11 (14%) 14 7Fabaceae 9 (30%) 13 (9%) 11 9Poaceae 9 (30%) 8 (18%) 10 9Passiflora 9 (30%) 17 (7%) 17 14Crescentia 12 (20%) 25 (3%) 12 12Phytelaphas 12 (20%) 24 (4%) 6 11Gossypium 12 (20%) 9 (16%) 7 13Bixa 15 (10%) 13 (9%) 9 15

Table 4Archaeofaunal data: rank order of top 15 zoological genera according to ubiquity andabundance by site (S) and individual excavation context (C). (%) records percentageubiquity by site and context (rounded calculations).

Taxon Ubiquity (S) Ubiquity (C) Abundance (S) Abundance (C)

Proechimys 1 (82%) 3 (20%) 3 3Odocoileus 2 (73%) 5 (16%) 6 6Oryzomys 2 (73%) 1 (36%) 1 1Sigmodon 4 (64%) 2 (21%) 4 4Sylvilagus 5 (55%) 7 (10%) 8 5Mazama 6 (45%) 14 (3%) 19 15Akodon 7 (36%) 15 (3%) 17 14Alouatta 7 (36%) 12 (4%) 13 12Dasyprocta 7 (36%) 4 (16%) 7 8Dasypus 7 (36%) 5 (16%) 2 2Didelphis 7 (36%) 11 (5%) 5 10Tayassu 7 (36%) 8 (8%) 12 9Marmosa 13 (27%) 12 (4%) 14 13Boa 14 (18%) 10 (7%) 10 11Cuniculus 15 (18%) 16 (2%) 16 16

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following section identifies these taxa, explores patterning in theirrespective ecologies, and suggests how theymight be recognized asproxy evidence for understanding prehistoric farming systemsutilized by Jama-Coaque II farmers during the Jama Valley’s laterprehistory.

5. Late pre-Columbian agroforestry in the Jama Valley

The highly ubiquitous and abundant plant and animal speci-mens that dominate sampled deposits in later prehistoric Jama-Coaque II contexts suggest the pre-Columbian presence offragmented forests resembling a kind of landscape mosaic oftenproduced through agroforestry. The various depositional contextsrepresented in the sample encompass different modes of assem-blage accumulation and preservation that incorporate thebyproducts of both intentionally discarded cultural refuse andaccidentally deposited local plant and animal residues, often inassociation with post-discard burning. The pattern of sharedecological features within this suite of plants and animals implicatea prehistoric background landscape that is characteristic of agro-forestry, based on observations of recent vegetation and agricul-tural studies in the Jama Valley, field-based research on neotropicalforest fragmentation, and natural histories of identified taxa (seediscussions and references in Stahl, 2000, 2006; Pearsall, 2004).

Ubiquitous wood specimens are common in most flotationsamples. They likely represent fire residue, either from cooking orperhaps refuse burning. These were the main modes of preserva-tion for all botanical macroremains, there being no evidence forstructural fires. Specimens of important economic plants, includingmaize kernels and cupules, bean, gourd, and cotton fragmentsregularly dominate the macroremain samples, as do root and tuberfragments. Many of the recovered but unidentified small seedslikely represent local “weeds”. Those ubiquitous and sometimesabundant small seeds that could be identified suggest the nearbypresence of open habitat. Members of the Solanaceae, eitherSolanum or Physalis, are commonly found in open areas such asstream edges, roadsides, and agricultural fields; some, such asground-cherries, are edible. A species of carpet weed (Trianthemaportulacastrum), a native herb of the Ecuadorian coast with edibleyoung leaves and stems, is common in open habitats. Seeds that arecomparable to Linum, a genus of flowering plants that includesherbs and subshrubs, are common. The majority of these inciden-tally charred and identified seeds were included in the recoveredsamples because they prefer open habitats that were local to thearea of deposition. It is unlikely that they represent weeds

harvested along with crops because most of the economic plantsentered the area of accumulation as hand-picked seeds, individu-ally excavated tubers, and harvested tree fruits.

The inference that most of the deposits represent accumulatedbyproducts of food consumption in associationwith plants adaptedto open conditions, receives further corroboration in the remainderof the recovered archaeobotanical assemblage. Some of the lesscommon genus-level macroremains are those of open area, weedyplants. They include the seeds of Teucrium, one of six genera of localmints common in open vegetation, and awidely occurring pigweedIresine herb or shrub which is presently found in both grazed andopen forest settings. Many of the family-level macrobotanicalidentifications also point to local open habitats. They include:sunflower and daisy relatives which are locally common weedycomponents in open areas; herbs of the spiderwort family found instream sides and cultivated fields; members of the cotton family,including the commonly recovered and identified Sida, all of whichhave been collected in open habitats; and, pokeweeds, knotweeds,and purslane from similarly open areas. Although this discussionwas limited to macroremains, identified phytoliths add arrowrootto the list of cultivated plants, as well as open area and weedysedges found in edges and harvested fields.

Abundant and ubiquitous genera of animals that dominate thearchaeobiological sample include local eurytopic or generalist taxathat thrive in areas cleared through natural disturbance or anthro-pogenic activity. In particular, “weedy” generalists as rodents, frogs,snakes, and understory avian insectivores are favored in areas ofhuman disturbance. Certain small rodents, including rice rats(Oryzomys and some recently revised genera of Oryzomyinerodents) and cotton rats (Sigmodon) are particularly common indisturbed habitats of second-growth forest and anthropogenicclearing. Both genera stand out in the sample for their ubiquity andhigh abundance, and when coupled with post-cranial specimens ofunidentified small rodents, suggest the presence of relativelycomplete skeletons that may indicate incidental deposition andburial. In particular, contextual associations in high resolutiondeposits suggest that many of these animals were accidentallydeposited and included into the archaeological record throughnatural entrapment (Stahl, 2000). Other relatively common localmicromammalian habitat generalists as grass mouse (Akodon) andmouse opossum (Marmosa), and less common squirrel (Sciurus),climbing rat (Rhipidomys), cane mouse (Zygodontomys), leaf nosebat (Phyllostomus), and fruit-eating bat (Artibeus) also implicate thelocal presence of early forest succession, disturbed habitat, andanthropogenic clearings.

The macrobotanical sample includes a significant component ofarboreal taxa that minimally suggests access to various useful trees,and likely implicates the deliberate management of various arborealcrops, avital componentof agroforestry. Amongst theubiquitous andabundant identified macroremains are numerous examples of seedcoat fragments that resemble the native Manabí tree Sideroxylonobtusifolium, a member of the Sapote family which has variouscommercial and medicinal uses in South America. Cotyledon frag-ments of sapote tree fruits, used in drinks and as secondary foodsources, were also identified. Other relatively ubiquitous and abun-dant arboreal genera identified in themacroremains include passionfruit (Passiflora), tree gourd (Crescentia), cadi palm (Phytelaphas)ea sourceof taguanuts, andachiote (Bixa) dye. Less common identifiedmacroremains add to the list of economically useful arboreal taxapresent in the sample, including coroso or macaw palm (Aiphanes),harvested for its nuts, and guava (Psidium), cultivated for its ediblefruit. Family-level identifications add edible soursop (Annonaceae),pechiche (cf. Vitex gigantea), tree legume, and fragments of differentkinds of unidentifiable large fruits or seeds that were common insamples. Phytolith identifications further contribute valuable

P.W. Stahl, D.M. Pearsall / Quaternary International 249 (2012) 43e52 51

mullullu and laurel (Boraginaceae), palo santo (Burseraceae), Gua-zuma, a small to medium tree found in open areas and secondarygrowthandused for itswood andflowers, andother families of trees,shrubs, and robust herbs like Heliconia, which invades gaps in forestclearings.

The archaeofaunal sample contributes a significant selection ofubiquitous and abundant specimens from economically usefulanimals whose habitat preferences implicate a background land-scape of agricultural clearings, edges, secondary growth, anddisturbed habitat. Intentionally managed active and fallow gardensare prime hunting spots as they provide attractive venues for manyneotropical rodent staples like spiny rat (Proechimys), agouti(Dasyprocta), and paca (Cuniculus), in addition to non-rodentgarden pests like opossum (Didelphis), armadillo (Dasypus) andrabbit (Sylvilagus). Ubiquitous and abundant evidence of largereconomically useful species as deer (Odocoileus and Mazama) andpeccary (Tayassu), may implicate agricultural clearings which theyinvade, and forest edges in which they thrive. Howler monkeys(Alouatta) are often the most common primate observed in forestfragments. Less ubiquitous and abundant edge generalists or frag-ment denizens as tree anteater (Tamandua), sloth (Bradypus),tinamou (Crypturellus) and iguana (Iguana), and opportunisticpredators including felids (Felis, Panthera) and boa constrictors(Boa) also suggest that a range of open habitats may have beenexploited by humans in the pre-Columbian past.

The archaeobiological sample is dominated by an assemblage ofplant and animal specimens that clearly implicates humanexploitation of a range of variably open habitats throughout theforested valley system. Some of the contexts represent locallyaccumulated and deposited specimens, and in many cases thesewere recovered in association with residues of economically usefulplants and animals that were likely pursued in areas at somedistance from their eventual site of deposition and burial. Theassemblage contains a mixture of accidentally entrappedcommensals that thrive in close proximity to humans, cultivatedeconomic plants and their vertebrate predators, and useful arborealproducts and forest gap denizens that suggest the strong possibilitythat humans had ready access to an agroforested landscape.

These interpretations are corroborated in a study of plantmicrofossils recovered from the deep alluvially-deposited terraceprofile at Río Grande (Veintimilla, 1998, 2000). A decrease inarboreal indicators implicates accelerated forest clearance from thefirst arrival of humans in the area. Abundant open-habitat plants inthe phytolith record suggest that tracts within the valley weremaintained in increasingly open conditions, especially before thethird volcanic event impacted the valley. Unlike other previousvolcanic perturbations, the area appears not to have been aban-doned; Jama-Coaque II farmers continued their previous agricul-tural trajectory through intensified land clearance. It is also at thistime that arboreal indicators increase, driven by an increase in palmphytoliths in the profile, along with the appearance of Heliconia.

6. Summary and conclusion

Farmers have lived in the Jama Valley of coastal lowland Ecuadorfor at least four millennia. The earliest evidence for its humanoccupation suggests that agricultural activities in the valley mayhave been localized around floodplains. A series of catastrophicvolcanic events punctuated the long sequence of valley occupationwith intermittent abandonment and repopulation up to theappearance of the Jama-Coaque culture in the third century beforeChrist. It is possible that various degrees of landscape fragmenta-tion and modification were present in the valley ecosystem at leastsince the arrival of its earliest human inhabitants (Stahl, 2006,2008); however, it may have been during the initial Jama-Coaque

I occupation with significant agroforestry production (Pearsall,2004). It is in the final phases of Jama-Coaque II settlementwhich began after a third volcanic event that blanketed the valleywith tephra somewhere between AD 300 and 550 that agroforestrymay have appeared in its most extensive areal manifestation. Theassociated archaeobiological samples of recovered and identifiedplants and animals strongly implicate access to a range of variablyopen habitats throughout the forested valley system. The evidencefor economic plants recovered in association with local weedy andcommensal taxa, forest gap users, and a range of tree crops,implicates a pre-Columbian form of agroforestry operating in theJama Valley by at least its Jama-Coaque II occupation. Indeed, it mayhave been crucial for surviving the effects of tephra fallout whichwas surely lethal for riverine habitats and floodplain agriculture(Pearsall, 1996, 2004; Stahl, 2008).

Vegetation clearance is a hallmark of the human footprint inforested settings. During their regular activities, many animalsroutinely disturb forest conditions and create commensal rela-tionships with other animals whose food availability increases asa factor of the disturbance, a condition which Terborgh (2000)characterized as the “beater syndrome.” Humans were more thanlikely aware of this relationship for a very long time and inten-tionally or unintentionally seized advantage of its productivebyproducts. Agroforestry is an old and ingenious example of humanproductive systems that have worked and continue to workthroughout tropical environments. It appears to have been thrivingand active in the Jama Valley where it helped to support thecomplex and populous Jama-Coaque II culture in the centuriesbefore its fateful encounter with the Spanish.

Acknowledgments

Funding for research was made possible through grants fromthe National Science Foundation (BNS-8709649, BNS-8908703,BNS-9108548) awarded to James A. Zeidler and Deborah M. Pear-sall. We thank all members of the Jama Valley Archaeological-Paleoethnobotanical Project, particularly Jim Zeidler, andacknowledge with gratitude the numerous people throughout thevalley who made this research possible.

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