Comparative examinations of societal stability and resilience point to long-term, regional oscillations in population (Riris et al. Reference Riris, Silva, Crema, Palmisano, Robinson, Siegel, French, Kirkeng Jørgensen, Yoshi Maezumi, Solheim, Bates, Davies and Xiaolin Ren2024; Scheffer et al. Reference Scheffer, Van Nes, Kemp, Kohler, Lenton and Chi2023). Turchin (Reference Turchin2005, Reference Turchin2009) calculated such oscillations for past agrarian state-level societies, holding the occupied area constant, as two centuries in length for a full growth-decline-growth cycle. Whitmore and colleagues (Reference Whitmore, Turner II, Johnson, Kates, Gottschang, Turner II, Clark, Kates, Richards, Mathews and Meyer1990) gauged that multiple century-level oscillations or millennial-level cycles also existed in such circumstances, in which shorter-term oscillations were evident but not addressed. If demographic oscillations were common for the societies in question, the case of the central Maya lowlands (CML), once home to a substantial population, stands as an exception. A millennium has passed since this rich and powerful portion of the Maya domain was densely occupied. Today, much of the CML remains a settlement frontier within and surrounding a biosphere reserve.
The greater Yucatán peninsular region has been home to lowland Maya peoples for at least four millennia. During the Late Classic period (ca. 550–830 c.e.; Table 1) of their occupation, the lands of, and adjacent to, the elevated interior (Dunning et al. Reference Dunning, Beach and Luzzadder-Beach2012), especially the CML, reached a peak in population numbers, supported by a large and complex built environment and extensive trade networks (Figure 1). The elevated interior constitutes a hilly limestone plateau (ca. 150–900 m above LMSL, local mean sea level), replete with seasonally inundated bajos, or sinks, extending about 400 km from the Puuc Hills in northern Yucatán to the central lakes of the Petén, Guatemala (Dunning et al. Reference Dunning, Beach and Luzzadder-Beach2012). The CML, in contrast, covers the southern and more moist part of the elevated interior, extending about 225 km north to south from southern Campeche and Quintana Roo, Mexico to the central Petén lakes (Turner and Sabloff Reference Turner and Jeremy2012).
Figure 1. The central Maya lowlands and entities referenced in the text (after Turner and Sabloff Reference Turner and Jeremy2012).
Significant population abandonment of the CML and other interior parts of the lowland Maya realm took place during the Terminal and Early Postclassic periods (ca. 830–1200 c.e.). A seasonal tropical forest overgrew the extensive infrastructural landscape that had sustained occupation of the CML for more than a millennium. The socioeconomic and political power of the lowland Maya moved with the population throughout the Terminal and Early Postclassic periods to the northern plains (e.g., Sabloff Reference Sabloff2007) and the eastern and western coastal lands (e.g., Ek Reference Ek and Braswell2014 ) of the peninsula. The elevated interior, foremost the CML, has subsequently remained sparsely populated and significantly rewilded, even to this day, compared to its conditions in the Classic period. This demographic history, including the absence of a population rebound, is as puzzling as has been the social, economic, and political collapse of the Classic-period Maya.
Improved understanding of the prolonged occupational decline of the CML may provide important insights about the prehispanic Maya (Turner Reference Turner2010). For example, why was the CML so densely populated with powerful city-states before the Terminal Classic period, given its subsequent occupational history? What advantages or disadvantages did the CML maintain during its occupational ascendancy that were maintained or lost? Were these factors largely environmental and material in kind (e.g., trade), or were they embedded in societal structures or cultural features?
Specific attention to the rebound topic is slim to our knowledge. A Google Scholar title search using different key phrases signaling long-term abandonment and rebound of the central and southern Maya lowlands or elevated interior revealed only one publication—Turner and Sabloff (Reference Turner and Jeremy2012)—which posed the rebound (or its absence) question but did not address it. The literature explicitly directed to the causes of this reoccupation failure but not captured in our key phrases, such as that by Demarest (Reference Demarest, Arnauld and Breton2013), also appears to be sparse. That dealing with systematic comparisons of the evidence between the major areas of Maya occupation and the lightly settled CML during the Postclassic period is sparser.
In contrast, extensive research on various facets of the human-environmental conditions of the Maya realm yields evidence and interpretations that are relevant to the rebound and related questions. We draw on this research to examine a set of push–pull, demographic factors operative during the Postclassic period for the northern and coastal occupational zones and the CML. These factors are those that have historically operated across agrarian societies: population pressures, environmental hazards, and resources. To these we add “infrastructure” or the willingness to rebuild the CML to the material standards of the areas from which Postclassic Maya would have emigrated. We compare these factors based on evidence that is quantifiable and likely to increase in detail and rigor in the near-term owing to ongoing Maya research. Unfortunately, we do not believe that the evidence is currently sufficient to warrant tests or models of their explanatory power. Rather, our effort points to some of the push–pull factors that should be included in future considerations of the problem.
We frame our effort by way of the human-environmental conditions that existed in the CML during the Late Classic period and interpretations of the drivers of the Maya societal collapse and depopulation that took place as articulated by Turner and Sabloff (Reference Turner and Jeremy2012) and others (e.g., Arnauld Reference Arnauld2024; Griffin et al. Reference Griffin, Oglesby, Sever, Nair and Iannone2014; Kennett and Beach Reference Kennett and Beach2013; Kennett et al. Reference Kennett, Breitenbach, Aquino, Asmerom, Awe, Baldini, Bartlein, Culleton, Ebert, Jazwa, Macri, Marwan, Polyak, Prufer, Rifley, Sodemann, Winterhalder and Haug2012; Luzzadder-Beach et al. Reference Luzzadder-Beach, Beach and Dunning2012). It involves: (1) the stressful conditions of the built environment of the CML during a time of intensive drought, urban collapse, and depopulation; (2) the evidence of changes in commercial trading routes that may have constrained the occupants of the CML to respond to the environmental changes underway; and (3) the low levels of population in the CML during the Postclassic period. This brief review, which may otherwise constitute the obvious for some experts, is warranted for at least two reasons. It provides updated information about the three CML issues noted, serving as a backdrop for our push–pull assessment, and counters persistent challenges about population dynamics and agrarian landscapes in the CML. Finally, we examine the possible push–pull factors that prevented the Postclassic Maya population of the northern and coastal plains of the Yucatán peninsular area from substantially reoccupying the CML during the 700–800 years between the abandonment of the CML and the Spanish takeover of the region beginning in 1539. This last part of a millennial long-wave cycle—from the middle 16th century to the present—constitutes a qualitatively distinct set of conditions that is not included in our assessment.
The central maya lowlands in the classic period
The CML covers a large swath of southern Quintana Roo and Campeche, Mexico, northwestern Belize, and northern Guatemala from the central Petén lakes to the border with Mexico (Figure 1; as demarcated, the CML is about 59,000 km2). The elevated interior commonly rises about 100 m LMSL from the peninsular coastal plains, ascending to 500 m LMSL in parts of the interior. Surface water is sparse, especially in the winter dry season, save for the deep, central Petén lakes and perennial wetlands, a few springs mostly situated along the western edge of the CML, and the headwaters of several rivers in the southern part of the peninsula that flow to the Caribbean Sea and Gulf of Mexico (Figure 1). The water table tends to be deep (>100 m; Bauer-Gottwein et al. Reference Bauer-Gottwein, Gondwe, Charvet, Marín, Rebolledo-Vieyra and Merediz-Alonso2011; Dunning et al. Reference Dunning, Brewer, Carr, Anaya Hernández, Beach, Chmilar, Grazioso Sierra, Griffin, Lentz, Luzzadder-Beach, Reese-Taylor, Saturno, Scarborough, Smyth, Valdez, Larmon, Lucero and Valdez2022; Moreno-Gómez et al. Reference Moreno-Gómez, Martínez-Salvador, Moulahoum, Liedl, Stefan and Pacheco2019) compared to the much shallower depth (<10 m) in the northern and coastal plains. As such, ground water in the CML was not readily accessible for the ancestral Maya (e.g., Lagomasino et al. Reference Lagomasino, Price, Herrera-Silveira, Miralles-Wilhelm, Merediz-Alonso and Gomez-Hernandez2015). In addition, sulfates residing in a gypsum-rich stratigraphy in the more northerly part of the CML can contaminate the groundwater (Perry et al. Reference Perry, Velazquez-Oliman, Leal-Bautista and Dunning2019).
Aguadas, or small-sized, usually seasonal pools of surface water exist throughout the CML, commonly located at the edges of wetlands where shallow sinks in the bedrock occur (Hansen et al. Reference Hansen, Bozarth, Jacob, Wahl and Schreiner2002). The Maya modified existing and constructed new aguadas and urban reservoirs to capture and store wet-season precipitation (Akpinar Ferrand et al. Reference Akpinar, Ezgi, Lentz and Jones2012), perhaps reducing percolation to groundwater (Perry et al. Reference Perry, Velazquez-Oliman, Leal-Bautista and Dunning2019). Maya attention to water-storage infrastructure makes the identification of individual aguadas as natural or constructed, or a combination thereof, difficult to determine in some cases (Ensley et al. Reference Ensley, Hansen, Morales-Aguilar and Thompson2021). Reservoirs, in contrast, were part of the urban infrastructure, complete with systems draining surface water to them (Matheny Reference Matheny1976; Scarborough Reference Scarborough1992).
The environmental conditions of the CML for cultivation excelled compared to lands in the north and to the non-riverine lands of the coastal plains. Precipitation, both average annual amounts (ca. 1,150–2,600 mm in the CML; Luzzadder-Beach et al. Reference Luzzadder-Beach, Beach, Hutson and Krause2016) and the length of the summer wet season, increases southward from the north coast of the peninsula, attested by the decreasing dry-season deciduousness of the upland forests. Mollisols, up to one meter in depth, support this vegetation, constituting a superior medium for cultivation within the tropical world (Labaz et al. Reference Labaz, Hartemink, Zhang, Stevenson and Kabała2024). Abundant wetlands (Ensley et al. Reference Ensley, Hansen, Morales-Aguilar and Thompson2021), commonly large depressions or bajos, inundate during the wet season and maintain clay-rich vertisols that serve cultivation well with soil moisture management (Wubie Reference Wubie2015). This soil may even have been moved to upslope terraces to enhance agricultural productivity (Hansen et al. Reference Hansen, Bozarth, Jacob, Wahl and Schreiner2002).
The CML and Maya lowlands in general have entertained large swings in climatic conditions over the millennia (Medina-Elizalde et al. Reference Medina-Elizalde, Burns, Lea, Asmerom, Von Gunten, Polyak, Vuille and Karmalkar2010), including multi-decadal droughts at the end of the Preclassic period (200–300 c.e.; Figure 2), influencing the collapse of important city-states. Rural settlements likely survived (Ebert et al. Reference Ebert, Peniche May, Culleton, Awe and Kennett2017), however, as they did with city-state collapses in the northern lowlands during subsequent drought conditions (Masson et al. Reference Masson, Hare, Peraza Lope, Kennett, Witschey, Russell, Serafin, James George, Flores Cobá, Delgado Kú, Escamilla Ojeda and Cruz Alvarado2024). The CML population recovered and grew from the Preclassic aridity, focused on different polities and locations. Another aridity trend began in the Early Classic (690 c.e.), generating multi-decadal droughts beginning about 820 c.e. with spikes in drought throughout the Terminal Classic and Early Postclassic periods (Figure 2). Intensive aridity occurred in 870 and 920–940 c.e., and there was a longstanding, extremely intense drought from 1000–1100 c.e. (Kennett et al. Reference Kennett, Breitenbach, Aquino, Asmerom, Awe, Baldini, Bartlein, Culleton, Ebert, Jazwa, Macri, Marwan, Polyak, Prufer, Rifley, Sodemann, Winterhalder and Haug2012). These climatic conditions were associated with social, political, and demographic changes, foremost in the CML (Kennett et al. Reference Kennett, Breitenbach, Aquino, Asmerom, Awe, Baldini, Bartlein, Culleton, Ebert, Jazwa, Macri, Marwan, Polyak, Prufer, Rifley, Sodemann, Winterhalder and Haug2012), leading to a political collapse from 800–820 c.e., urban collapse from 900–1000 c.e., and a demographic collapse from 1000–1200 c.e. (Arnauld Reference Arnauld2024).
Figure 2. Chronologies of prehispanic occupation and climatic aridity episodes in the Maya lowlands and societal collapse and depopulation of the central Maya lowlands (following Arnauld Reference Arnauld2024; Kennett et al. Reference Kennett, Breitenbach, Aquino, Asmerom, Awe, Baldini, Bartlein, Culleton, Ebert, Jazwa, Macri, Marwan, Polyak, Prufer, Rifley, Sodemann, Winterhalder and Haug2012).
This simplification of environmental conditions in the CML provides a rudimentary base on which to examine its occupancy in the Late Classic to Early Postclassic periods (ca. 550–1200 c.e.), a time in which the number and density of population reached significant levels and subsequently declined precipitously, if varied by location (Arnauld et al. Reference Arnauld, Lemonnier, Hiquet, Chase, Chase and Chase2024). The CML was home to abundant city-states, including those large in area, monumental architecture, and population: Tikal, Uaxactún, Calakmul, Río Bec, Becan, and others. These sites reached the tens of thousands in population (Arnauld et al. Reference Arnauld, Lemonnier, Hiquet, Chase, Chase and Chase2024; Webster Reference Webster2018), perhaps with muted occupational density (Isendahl Reference Isendahl2012). Significantly, the villages and hamlets of the urban hinterlands were well occupied (Canuto and Auld-Thomas Reference Canuto, Auld-Thomas, Chase, Chase and Chase2024; Hutson et al. Reference Hutson, Dunning, Cook, Ruhl, Barth and Conley2021) and the infrastructure of their cultivated lands (i.e., landesque capital) was substantial, save for patches of managed forests. Travel route systems connected urban sites, including the use of sacbes or elevated causeways, especially useful for crossing wetlands. Many known sacbes date to the Preclassic period (Hansen et al. Reference Hansen, Morales-Aguilar, Thompson, Ensley, Hernandez, Schreiner, Suyuc-Ley and Martinez2023), but their links to Classic-period settlements (LaRocque et al. Reference LaRocque, Leblon, Gerald and Folan2022) suggest their sustained maintenance.
Over the last 30 years individual site and area estimates for the Maya realm or parts of it during the Late Classic period have signaled large populations and high densities (e.g., Hutson Reference Hutson, Chase, Chase and Diane Z.2024). Those for the CML at large have reached more than 150 people per square kilometer, but with lower ranges beginning at 80 people per square kilometer (e.g., Canuto et al. Reference Canuto, Estrada-Belli, Garrison, Houston, Jane Acuña, Kováč, Marken, Nondédéo, Auld-Thomas, Castanet, Chatelain, Chiriboga, Drápela, Lieskovský, Tokovinine, Velasquez, Juan, Díaz and Shrestha2018; Hutson et al. Reference Hutson, Dunning, Cook, Ruhl, Barth and Conley2021; Turner Reference Turner, Culbert and Rice1990). Webster (Reference Webster2018) cautions that the total populations derived from such densities are excessive, at least as applied over extensive areas. He significantly reduces the higher population densities proposed by others to as low as about seven people per square kilometer for a large area (one million people spread over 150,000 km2) that includes the CML. Webster recognizes that patches supportive of high levels of occupation existed, such as Tikal with densities of 127 to 175 people per square kilometer, owing to “productive” land, presumably the uplands as opposed to wetlands. The frequency of such zones would appear to be large, however, as indicated by the massive amount of landscape infrastructure (i.e., temples to terraces) identified throughout the CML by Lidar (Beach et al. Reference Beach, Luzzadder-Beach, Krause, Guderjan, Valdez, Fernandez-Diaz, Eshleman and Doyle2019; Canuto et al. Reference Canuto, Estrada-Belli, Garrison, Houston, Jane Acuña, Kováč, Marken, Nondédéo, Auld-Thomas, Castanet, Chatelain, Chiriboga, Drápela, Lieskovský, Tokovinine, Velasquez, Juan, Díaz and Shrestha2018; Chase et al. Reference Chase, Chase, Chase, Chase, Chase, Chase and Chase2024; Golden et al. Reference Golden, Murtha, Cook, Shaffer, Schroder, Hermitt, Alcover Firpi and Scherer2016; Hansen et al. Reference Hansen, Morales-Aguilar, Thompson, Ensley, Hernandez, Schreiner, Suyuc-Ley and Martinez2023; Hutson et al. Reference Hutson, Dunning, Cook, Ruhl, Barth and Conley2021; Schroder et al. Reference Schroder, Murtha, Golden, Anaya Hernández, Scherer, Morell-Hart, Almeyda Zambrano, Broadbent and Brown2020; Stanton et al. Reference Stanton, Hutson, Ardren, Chase, Chase and Chase2024), much, if not most, of which relates to the Classic period, and the increasing evidence of wetland uses throughout the Maya realm (Fedick et al. Reference Fedick, Morell-Hart and Dussol2023; Luzzadder-Beach et al. Reference Luzzadder-Beach, Beach and Dunning2012). Lidar data have led to estimates of 70 to 120 persons per square kilometer for the entirety of a Petén zone, encompassing urban and rural settlements across 60,000 km2 (Canuto and Auld-Thomas Reference Canuto, Auld-Thomas, Chase, Chase and Chase2024), that includes the southern half of the CML as defined here.
The critical issue for our discussion is not the precise density of the CML during Late Classic to Terminal Classic periods before the urban collapse (ca. 900–1000 c.e.; Table 1). Rather, it is the range of densities known to be associated with the scale of occupational and landesque infrastructure present in the CML during that time. The abundance of monumental features, residential abodes, reservoirs, terraces, wetland fields, orchard gardens, and causeways (increasingly revealed by Lidar data), as well as paleodemographic evidence (Olga Hernández Espinosa and Morfin Reference Olga Hernández Espinoza and Marquez Morfin2015), points to elevated levels of population pressures or densities, even accounting for household movements between urban and rural residences (Arnauld et al. Reference Arnauld, Lemonnier, Hiquet, Chase, Chase and Chase2024), if such movements were significant. Evidence of landesque capital among contemporary, self-producing communities (Turner et al. Reference Turner, Robert and Anthony1977) strongly suggests that the relic Maya infrastructure implies population densities no lower than 50 people per square kilometer throughout the CML and over the century mark for specific areas. This evidence also points to an environmentally transformed CML—not just urban infrastructure—managing to supply water and agricultural goods, not one primarily engaged in forest-based production systems (Ford Reference Ford2015), although managed forests existed. The surface transformation in question was so intensive that it affected the base karst geomorphosystems (Lebedeva et al. Reference Lebedeva, Mikhalev and A2017).
The paleoenvironmental data within the CML and elsewhere in the Maya domain support this transformation and its population inferences (Beach et al. Reference Beach, Luzzadder-Beach, Cook, Dunning, Kennett, Krause, Terry, Trein and Valdez2015; Luzzadder-Beach et al. Reference Luzzadder-Beach, Beach and Dunning2012; Paine and Freter Reference Paine and Freter1996; Turner and Sabloff Reference Turner and Jeremy2012). With a few variations (Emery and Thorton Reference Emery and Thornton2008; Ford Reference Ford2022; McNeil et al. Reference McNeil, Burney and Burney2010), this record includes: a loss in arboreal pollen by an order of magnitude approaching 90 percent (e.g., Battistel et al. Reference Battistel, Roman, Marchetti, Kehrwald, Radaelli, Balliana, Toscano and Barbante2018; Wahl et al. Reference Wahl, Byrne, Schreiner and Hansen2006); huge increases in vegetative disturbance indicators (Wahl et al. Reference Wahl, Byrne, Schreiner and Hansen2007; Wahl et al. Reference Wahl, Estrada-Belli and Anderson2013); significant decline in large-tree timber for construction at major sites, such as Tikal and Calakmul (Lentz and Hockaday Reference Lentz and Hockaday2009; Lentz et al. Reference Lentz, Dunning, Scarborough, Magee, Thompson, Weaver, Carr, Terry, Islebe, Tankersley, Grazioso Sierra, Jones, Buttles, Valdez and Ramos Hernandez2014); and a major decline in the apparent consumption of white-tailed deer (Emery Reference Emery2007), indicative of various environmental stressors, including major deforestation.
Landscape ingenuity supported the Maya through earlier drought periods (e.g., in the Late Preclassic and Early Classic periods; Kennett et al. Reference Kennett, Breitenbach, Aquino, Asmerom, Awe, Baldini, Bartlein, Culleton, Ebert, Jazwa, Macri, Marwan, Polyak, Prufer, Rifley, Sodemann, Winterhalder and Haug2012; Figure 2). The overall trend in aridity from the mid-Late Classic to the latter Early Postclassic (Figure 2), and the accompanied multi-decadal drought phases over that time span, amplified by the scale of landscape changes undertaken by the Maya, extended and heightened the intensity of aridity from 1020 c.e. to 1100 c.e. (Turner and Sabloff Reference Turner and Jeremy2012). Such land-atmospheric dynamics, or the consequences of them, were likely novel to the Maya experience, and should be understood as complementary to but superseding the case of Late Classic land degradation and the inability to supply cultivated foods, proposed fifty-years past (e.g., Culbert Reference Culbert1973).
The desiccation evidence is so extensive and robust that it need not be reiterated here (Douglas et al. Reference Douglas, Pagani, Canuto, Brenner, Hodell, Eglinton and Curtis2015; Douglas et al. Reference Douglas, Demarest, Brenner and Canuto2016; Evans et al. Reference Evans, Bauska, Gazquez-Sanchez, Brenner, Curtis and Hodell2018; Gill Reference Gill2000; Hoggarth et al. Reference Hoggarth, Restall, Wood and Kennett2017; Kennett and Beach Reference Kennett and Beach2013; Luzzadder-Beach et al. Reference Luzzadder-Beach, Beach and Dunning2012). The critical point is that the aridity and size of population created major societal and environmental stressors that surely served as drivers, if partial in kind, of a condition akin to a tipping point and regime shift of the human-environmental systems in the CML (Arnauld Reference Arnauld2024; Kennett et al. Reference Kennett, Breitenbach, Aquino, Asmerom, Awe, Baldini, Bartlein, Culleton, Ebert, Jazwa, Macri, Marwan, Polyak, Prufer, Rifley, Sodemann, Winterhalder and Haug2012; Lentz et al. Reference Lentz, Dunning, Scarborough, Magee, Thompson, Weaver, Carr, Terry, Islebe, Tankersley, Grazioso Sierra, Jones, Buttles, Valdez and Ramos Hernandez2014; Lucero Reference Lucero2002; Turner and Sabloff Reference Turner and Jeremy2012). The CML witnessed a slow erosion of its occupants (Chase et al. Reference Chase, Chase, Morris, Morris, Jones, Awe and Helmke2008), such that by the beginning of the Late Postclassic (ca. 1200 c.e.) it held a shadow of its former population. Unlike the documented cases of severe drought and famine among the colonial-period Maya in the northern lowlands, the CML population did not rebound (Hoggarth et al. Reference Hoggarth, Restall, Wood and Kennett2017).
Challenges to the desiccation role (e.g., Iannone et al. Reference Iannone, Yeager, Hodell and Iannone2014) focus on its primacy as the cause of the 800–1200 c.e. political, urban, and demographic collapses noted above (Figure 2; Arnauld Reference Arnauld2024). Considering the entire Maya lowlands, for example, city-state collapses and drought do not necessarily correlate synchronously (Iannone et al. Reference Iannone, Yeager, Hodell and Iannone2014), leading some researchers to conclude that drought served as a driver only in the later stages the collapse dynamics and only for certain lowland regions (Demarest Reference Demarest, Arnauld and Breton2013). Other causes, therefore, were at play. This argument is consistent with historical data from elsewhere (Butzer Reference Butzer2012; Haldon et al. Reference Haldon, Mordechai, Newfield, Chase, Izdebski, Guzowski, Labuhn and Roberts2018) indicating that climate aridity alone rarely explains societal collapse and depopulation (e.g., Griffin et al. Reference Griffin, Oglesby, Sever, Nair and Iannone2014; Masson Reference Masson2012). Rather, stressors creating societal collapses and depopulation commonly involve multiple, complex factors with which climate drivers interact. Among such interactions, Turner and Sabloff (Reference Turner and Jeremy2012), among others, suggested that significant shifts in commercial trade routes may have served as an additional factor in collapse and depopulation of the CML (also, Demarest Reference Demarest, Arnauld and Breton2013).
Postclassic trade-route shifts
Half a century ago, Rathje and Sabloff (Reference Rathje and Sabloff1973; also, Sabloff and Rathje, Reference Sabloff and Rathje1975; Sabloff Reference Sabloff2007) argued that the Postclassic Maya, influenced by the Putún or Chontol Maya from the southwestern part of the peninsula (Ek Reference Ek and Braswell2014), altered the political economy of the lowland Maya realm from that which existed previously in the CML and interior area at large. Occupying the northern plains and coastal zones of the peninsular region, the Postclassic Maya were more mercantile than those of the Classic-period elite, “... interested in keeping … capital liquid and in finding ways, such as mass production, to increase the volume, extent, and efficiency of long-distance exchange” (Sabloff Reference Sabloff2007:17), including that of bulk goods. Salt, cacao, cotton, honey, obsidian, copper, gold, and henequen were major goods of trade (Andrews Reference Andrews1980; Bianco et al. Reference Bianco, Alexander, Rayson, Jennifer and Thomas2017; Hutson and Dahlin Reference Hutson, Dahlin and Scott2017; Meyers Reference Meyers, Jennifer and Thomas2017; Sabloff Reference Sabloff2007). Commercial networks facilitated trade (Andrews Reference Andrews, Scott and Ardren2020; Sabloff Reference Sabloff2007) in which cacao beans, cotton textiles, copper objects and, perhaps, salt cakes served as monetized mediums (Baron Reference Baron2018; McKillop Reference McKillop2021; Sampeck Reference Sampeck2021).
Commercial trade was not novel to the Postclassic Maya, however. It was well established long before the Postclassic period (e.g., Chase and Chase Reference Chase and Chase2014; Masson et al. Reference Masson, Freidel, Demarest, Chase and Diane2020), in which merchants and markets were foundational to the economy (King Reference King2015; Masson and Freidel Reference Masson and Freidel2012). For example, several major exchange systems in the CML traded cotton. One exchange linked the Tabasco lowlands to Calakmul, and another connected Honduras to Tikal (Reents-Budet and Bishop Reference Reents-Budet, Bishop, Masson, Freidel, Demarest, Chase and Chase2020), consistent with interpretations that Tikal controlled trade with the Maya highlands (Woodfill and Andrieu Reference Woodfill and Andrieu2012).
The Postclassic shift in political economy identified by Rathje and Sabloff (Reference Rathje and Sabloff1973) resided not in the existence of trade per se (e.g., implied in Eppich Reference Eppich, Masson, Freidel, Demarest, Chase and Diane Z.2020) but in the transition from a Classic-period market system apparently controlled by the political elite (Arnauld Reference Arnauld2024) to a mercantile system in the Postclassic period with its accompanying commercial class (Masson and Freidel Reference Masson and Freidel2012), which may have penetrated the non-elite classes (Hutson and Dahlin Reference Hutson, Dahlin and Scott2017). This shift in political economy was marked by a major flow of trade in which sea routes overwhelming prevailed during the Postclassic period compared to land routes (Arden and Lowry Reference Ardren and Lowry2011; Glover et al. Reference Glover, Hruby, Rissolo, Ball, Glascock and Steven Shackley2018; McKillop Reference McKillop1996; Rosenswig and Masson Reference Rosenswig and Masson2002), even for short and medium hauls (e.g., McKillop Reference McKillop, Hofman and Bright2010). Commerce circumnavigated the peninsula, which was ringed by ports and saltworks and included an inland coastal waterway along its northwestern-northern coastline (Figure 1) (Andrews Reference Andrews, Scott and Ardren2020; Ardren and Lowry Reference Ardren and Lowry2011; Demarest Reference Demarest, Arnauld and Breton2013; Glover et al. Reference Glover, Rissolo, Mathews and Ford2011; McKillop Reference McKillop2005, Reference McKillop, Hofman and Bright2010).
Coastal routes existed early in Maya history (e.g., Andrews Reference Andrews, Scott and Ardren2020; Robles Castellanos et al. Reference Robles Castellanos, Andrews, Chuc Aguilar, Masson, Freidel, Demarest, Chase and Chase2020), however, as did the inland coastal waterway and the use of the north–south trending Usumacinta River to the west of the CML. Yet, overland routes were highly active in the CML before the Postclassic period, as documented for trade in obsidian (Golitko et al. Reference Golitko, Meierhoff, Feinman and Williams2012). A major flow of goods was routed either way from the Caribbean to the Gulf of Mexico across the lands of the elevated interior, facilitated by riverine routing linking the coasts to the inland elevated terrain: the New, Hondo, and Belize rivers on the eastern and Candelaria, Champotón, and Usumacinta rivers on the western coasts of the peninsula, respectively (Figure 1). At least one assessment generates three least-cost transport routes crossing the CML and serving its urban centers (Volta et al. Reference Volta, Gunn, Folan, Folan, Braswell, Masson, Freidel, Demarest, Chase and Chase2020). These routes appear to have become inactive or significantly less active during Postclassic times.
Demonstrations of the sequencing and causes of the decline of the interior CML routing and the subsequent dominance of a coastal one entering the Postclassic period are sparse. The depopulation of the CML would have severely reduced trade needs, relationships, and routing across the interior, favoring sea routes. Alternatively, such routing shifts in tandem with other stressors would have disrupted the economies of the CML polities (Lucero Reference Lucero2002) and destabilized city-state alliances (Martin Reference Martin2020), affecting trade. Chaos among CML city-states following the defeat of Calakmul by Tikal, for instance, may have enhanced sea routing (Volta et al. Reference Volta, Gunn, Folan, Folan, Braswell, Masson, Freidel, Demarest, Chase and Chase2020). Loss of trade within the CML, in turn, would have reduced the capacity of polities to address the mounting human-environmental stresses of the Terminal and Early Postclassic periods, especially regarding agriculture. The level of polity investment, if any, given to agrarian infrastructure and management is not clear. The indirect negative impacts on farming systems among the urban hinterlands, however, would have increased as city-state commerce decreased. The specifics of our argument notwithstanding, Golitko and colleagues (Reference Golitko, Meierhoff, Feinman and Williams2012) concur that a significant shift from interior to seagoing trade routes emerged before the urban decline of the CML (and elevated interior at large) and served as a direct causal factor for the societal collapse and depopulation of the CML. While such claims require more evidence, it is safe to assume that strong interactions existed among the trade-route shift, the demise of the CML, and the resulting long-term occupation of the northern Maya and coastal plains.
Postclassic period depopulation of the central maya lowlands
Specifying the Postclassic population density of CML at large, or at least establishing a range of densities, is useful for comparisons of the demographic pressures of the northern and coastal lowlands with the CML. Deriving such estimates has proven difficult, however, despite the general understanding of sparse settlement in the CML at large at that time (e.g., Demarest Reference Demarest, Arnauld and Breton2013). Generating occupational densities is dampened by the variations in settlements over the length of the Postclassic (ca. 950 c.e. to 1539 c.e.), the occupation of the Petén lake zone at the turn of the Terminal-Early Postclassic periods versus the Late Postclassic Itza entry, and the paucity of evidence for the remainder of the CML (Arnauld Reference Arnauld2024).
Recognizing these problems, the archaeological record fails to indicate reoccupation of the Classic-period urban sites or the development of new settlements with substantial construction in the CML beyond the lake zone (e.g., Dunning et al. Reference Dunning, Beach, Grazioso Sierra, Jones, Lentz, Luzzadder-Beach, Scarborough and Smyth2013). Evidence of the use of significant agricultural infrastructure in the CML does not exist for this time either (e.g., Luzzadder-Beach et al. Reference Luzzadder-Beach, Beach and Dunning2012), a strong indicator that Postclassic land pressures were much lower than those existing before the depopulation. Spanish accounts also indicate the paucity of population in the CML at contact times (Clendinnen Reference Clendinnen2003; Scholes and Roys Reference Scholes and Roys1968). Following one such account of a village population and the largely vacant area surrounding it in the northeastern portion of the CML, Thompson (Reference Thompson1966) proposed a density of only two people per square kilometer.
Even the occupation of the central Petén lake zone does not signal substantial population densities. Occupational losses in the Early Postclassic period, for instance, resulted in an underpopulated condition in which local conflicts generated a consolidation of peoples at several sites (Rice et al. Reference Rice, Rice, Pugh, Marquínez and Campillo1998; also, Schwarz Reference Schwarz2009). The Kowoj were present north of the lake zone, and the Yalain east of the zone (Rice and Rice Reference Rice and Rice2018b; but see Rice et al. Reference Rice, Rice, Kepecs, Alexander, Kepecs and Rani2005). The Kejache were present farther north of the lake zone, extending toward the modern-day border between Guatemala and Campeche. By early colonial times, the evidence of settlements in this part of the CML is slim. Late Postclassic immigration added people and polities to the lake zone (Jones Reference Jones1998; Rice Reference Rice2019; Rice and Rice Reference Rice and Rice2018a), such as that of the Itza, who arrived in either the 1200s or the 1400s, taking over the western part of the lake zone (Jones Reference Jones1998; Rice and Rice Reference Rice, Rice, Parker and Rodseth2005). The fact that the Itza and other Maya peoples could settle, even in the more occupied portions of the CML, is indicative of open or sparsely used lands.
The paleoenvironmental data also support sparse Postclassic occupancy of the CML. They indicate a major reduction in disturbance taxa and a return of forest cover beginning about 850 to 1000 c.e. (e.g., Battistel et al. Reference Battistel, Roman, Marchetti, Kehrwald, Radaelli, Balliana, Toscano and Barbante2018; Curtis et al. Reference Curtis, Brenner, Hodell, Balser, Gerard and Hooghiemstra1998) and, about 300 to 500 years before the Spaniards arrived, the forests and soils of the CML had regenerated in the Petén lake zone (Mueller et al. Reference Mueller, Islebe, Anselmetti, Ariztegui, Brenner, Hodell, Hadjas, Hamann, Haug and Kennett2010) and throughout the CML. A second transformation or rewilding had taken place (Wahl et al. Reference Wahl, Byrne, Schreiner and Hansen2006, Reference Wahl, Byrne, Schreiner and Hansen2007), despite the polities anchored in the lake zone. The massive forests of the CML confronted a Cortez-led expedition, which struggled to traverse them en route to Honduras, encountering nonexistent and overgrown trails and a paucity of settlements to supply food until arriving among the Itza (Cerwin Reference Cerwin1963). Subsequent Spanish ventures in the late 1600s from northern Yucatán into the CML also recorded the massive forests and sparse occupation (Scholes and Roys Reference Scholes and Roys1968).
Given this record, the estimate by Whitmore and associates (Reference Whitmore, Turner II, Johnson, Kates, Gottschang, Turner II, Clark, Kates, Richards, Mathews and Meyer1990) of a Postclassic maximum occupancy of the CML of 20–25 people per square kilometer seems excessive. If such densities existed, they were limited to parts of the central lake zone. The population density of the CML at large was surely in the single digits.
Absence of a millennial population rebound
We began by noting that large population collapses among past agrarian societies, especially those occupying sizable areas, tended to rebound over centuries to millennia, especially. Such a rebound did not take place in the CML during the more than half a millennium between the Terminal Classic period and the beginning of the colonial era, and has not taken place to this day, more than a millennium from the initial population decline. Many, if not most, Maya experts would concur with this assessment in its broad strokes, if not necessarily with the details and interpretations provided here.
Given a return to more humid precipitation regimes, the forest and soils of the CML regenerated in the latter part of Early Postclassic period (1000–1200 c.e.), taking no more than 260 to 280 years, respectively, to recover after the depopulation of the region (Mueller et al. Reference Mueller, Islebe, Anselmetti, Ariztegui, Brenner, Hodell, Hadjas, Hamann, Haug and Kennett2010; also Read and Lawrence Reference Read and Lawrence2003). This recovery involved strong legacy effects, however. The Maya altered the composition of tree species and disturbed soil surfaces (Brokaw et al. Reference Brokaw, Ward, Beach, Luzzadder‐Beach, Walling, Cortes‐Rincon and Valdez2025), foremost those maintaining decayed limestone infrastructure. Soil nutrients and moisture were regained, however. Why, then, did the population of the CML fail to rebound over the centuries that passed before Spanish conquest halted Maya control over their realm, especially given the agricultural qualities of the CML compared to the northern Maya lowlands? The answer to this question, which may seem intuitive to Maya scholars, is lacking in terms of empirical assessments or modeling exercises that examine the demographic push–pull factors of the northern and coastal plains versus the CML. Given this circumstance, we briefly entertain those push–pull factors common to migration studies of agrarian communities and for which a modicum of numerical evidence can be advanced: population pressures, environmental hazards, resources, and infrastructure.
Population pressures
The population density of the CML throughout the Postclassic period was small, surely in the low single digits as noted above, providing large areas for occupation. That for the northern lowlands, however, does not appear to have been sufficiently severe to trigger the need for migrations. Recent assessments point to a maximum population of 800,000 in the northern lowland during the Late Postclassic period (Hoggarth et al. Reference Hoggarth, Restall, Wood and Kennett2017; Masson et al. Reference Masson, Hare, Peraza Lope, Kennett, Witschey, Russell, Serafin, James George, Flores Cobá, Delgado Kú, Escamilla Ojeda and Cruz Alvarado2024). This population was scattered across numerous settlements of diverse sizes in which the largest was Mayapan with 12,300 to 21,500 occupying its core and periphery, respectively (Masson and Peraza Lope Reference Masson and Lope2014). Webster’s (Reference Webster2018) high-end population for the northern lowlands also resides at 800,000. Using that figure, and accounting for the 350 by 150 km swath across the whole terrain of the northern plains of the Yucatán Peninsula (ca. 52,000 km2)—from east to west coasts and from the north coast to the Puuc Hills—yields a population density of 15 people per square kilometer, rising to 19 people per square kilometer if the population is one million. Considered alone, such densities are not levels indicative of high population pressures by way of comparisons to other agrarian societies (Turner et al. Reference Turner, Robert and Anthony1977; Webster Reference Webster2018: table 2), suggesting that this potential push factor in the northern lowlands was not strong.
Population or land pressures for agrarian societies, however, are a product of the density of the population relative to the agricultural qualities of the environment occupied, a factor that we address below. Despite the less than high quality environmental conditions in the northern lowlands and much of the coastal zones, the absence of a spillover of population from the occupied zone into the CML suggests that land pressures were not extreme in the Postclassic occupational areas. Indeed, this is a major rationale for our conclusion that the population densities for the coastal zones were not excessive, given the paucity of demographic evidence for the entirety of the eastern and western coastal zones.
Environmental hazards
The entire Yucatán peninsular region suffers from drought episodes and hurricanes. Drought is recurrent in the paleorecord throughout the Maya lowlands (Figure 2), with intensity levels varying locationally by episode. Fine-tuned spatiotemporal evidence (1981–2011) demonstrates annual droughts about every four years, on average, somewhere in the peninsular area (De la Barreda et al. Reference De la Barreda, Metcalfe and Boyd2020). Periods of aridity affected the northern lowlands in the Postclassic period and subsequently (Kennett et al. Reference Kennett, Breitenbach, Aquino, Asmerom, Awe, Baldini, Bartlein, Culleton, Ebert, Jazwa, Macri, Marwan, Polyak, Prufer, Rifley, Sodemann, Winterhalder and Haug2012; Masson and Peraza Lope Reference Masson and Lope2014), with Spanish documented impacts indicative of food hardships in colonial times (Hoggarth et al. Reference Hoggarth, Restall, Wood and Kennett2017). The Terminal-Postclassic demise of Chichén Itzá (Andrews et al. Reference Andrews, Wyllys Andrews and Robles Castellanos2003), for example, may have been associated with intensive aridity between 1000 and 1100 c.e. (Figure 2), and conflicts among polities in the Postclassic period were associated with drought episodes (Kennett et al. Reference Kennett, Masson, Lope, Serafin, George, Spencer, Hoggarth, Culleton, Harper, Prufer, Milbrath, Russell, Uc Gonzalez, McCool, Aquino, Paris, Curtis, Marwan, Zhang, Asmerom, Polyak, Carolin, James, Mason, Henderson, Brenner, Baldini, Breitenbach and Hodell2022). Yet, the abundant rural settlements in the north persisted (Masson et al. Reference Masson, Hare, Peraza Lope, Kennett, Witschey, Russell, Serafin, James George, Flores Cobá, Delgado Kú, Escamilla Ojeda and Cruz Alvarado2024), and the resiliency of the Maya at a regional level of assessment persisted into contact times (Kennett et al. Reference Kennett, Masson, Lope, Serafin, George, Spencer, Hoggarth, Culleton, Harper, Prufer, Milbrath, Russell, Uc Gonzalez, McCool, Aquino, Paris, Curtis, Marwan, Zhang, Asmerom, Polyak, Carolin, James, Mason, Henderson, Brenner, Baldini, Breitenbach and Hodell2022). Importantly, the Postclassic droughts in question were likely experienced in the CML, if varying in intensity. Neither the northern coastal lowlands nor the CML, therefore, had a major advantage regarding hazards of aridity.
The synchronous character of drought across the Maya realm is not well matched by hurricane frequency and damage severity, as historically recorded. Hurricanes track across the entire peninsular area, invariably slamming the eastern coastline but reducing in strength inland and on the western coastline, lowering the damage to crops and landscapes. Their frequency and intensity, however, trend from the north-northeastern part of the peninsula southward along the Caribbean coast into Belize. One hurricane event occurs every four to ten years by location in the northeastern zone, but only about every 30 years for the CML (Boose et al. Reference Boose, Foster, Barker Plotkin, Hall, Fedick, Allen and Gomez-Pompa2003; Romero and León-Cruz Reference Romero and Francisco León-Cruz2024). If such patterns of frequencies existed in the past, and we are aware of no evidence that they did not, the CML would have been a more friendly location for occupation. No evidence exists, however, of hurricane-induced migrations during the Postclassic period from the more hazardous locations in the north-northeast lowlands leading to permanent occupation of the CML. Reduced hurricane damage in the CML, therefore, appears to have constituted a low pull factor.
Resources
Major distinctions exist between the northern and coastal lowlands and the CML in terms of natural capital and the environmental (ecosystem) services that followed from them during the Postclassic period. This capital—precipitation, soil, and potable water, all critical resources for agrarian societies (Arnauld Reference Arnauld2024), as well as lands suitable for salt production and access to marine and riverine foods—varied differentially among the areas examined.
The immediate coastal zone of the northwestern peninsula currently averages 600–800 mm of annual precipitation. Inland, however, where the preponderance of northern Postclassic Maya settlements existed, the land receives 1,000–1,200 mm. In contrast, the CML maintains average annual precipitation ranging up to 2,500–2,600 mm (Luzzadder-Beach et al. Reference Luzzadder-Beach, Beach, Hutson and Krause2016). The amount of precipitation also equates to the length of the principal growing season, which is longer in the CML than in the northern lowlands. The east and west coastal lands mimic this north-to-south increase in humidity and growing seasons.
The northern lowlands maintain a variety of cultivation micro-niches (Munro-Stasuik et al. Reference Munro‐Stasiuk, Kam Manahan, Stockton and Ardren2014) and soil types, although rendzinas are common. All upland soils are shallow in depth, often exceptionally so, and scattered among surface limestone bedrock (Beach Reference Beach1998; Sedov et al. Reference Sedov, Yazmin Rivera-Uria, Ibarra-Arzave, García-Ramírez, Solleiro-Rebolledo, Cabadas-Báez, Valera-Fernández, Díaz-Ortega, Guillén-Domínguez, de Jesús Moreno-Roso, Fedick, Leonard, Golden, Morell-Hart and Liendo-Stuardo2023). Small, shallow cavities in the underlying bedrock provide more soil depth, although the soil moisture retention proves to be problematic. Seasonally inundated wetlands with shallow soils (e.g., calcisols) are present near the coastline. While adequate for cultivation (Leonard et al. Reference Leonard, Sedov, Solleiro-Rebolledo, Fedick and Diaz2019; Sedov et al. Reference Sedov, Yazmin Rivera-Uria, Ibarra-Arzave, García-Ramírez, Solleiro-Rebolledo, Cabadas-Báez, Valera-Fernández, Díaz-Ortega, Guillén-Domínguez, de Jesús Moreno-Roso, Fedick, Leonard, Golden, Morell-Hart and Liendo-Stuardo2023), the soils of the northern lowlands are not of the same quality as those in the CML. The upland mollisols, mostly troporendolls, of the CML are deeper and of higher quality for cultivation (Liu et al. Reference Liu, Lee Burras, Kravchenko, Duran, Huffman, Morras, Studdert, Zhang, Cruse and Yuan2012) than the northern rendzinas. In addition, the clay-rich vertisols of the CML wetlands may also serve cultivation well if managed properly. Similar to Indigenous peoples throughout the Western Hemisphere, the Maya long maintained these management skills (Beach et al. Reference Beach, Luzzadder-Beach, Krause, Guderjan, Valdez, Fernandez-Diaz, Eshleman and Doyle2019). The Classic-period population size and the abundance of landesque capital in the CML attests to the advantages of soils, precipitation, and growing season there (e.g., Turner and Sabloff Reference Turner and Jeremy2012).
Underserved cultivation-wise compared to the CML, the northern lowlands and the coastal zones maintain distinctive advantages in access to potable groundwater through abundant cenotes (sinks) and caves that reach the water table (Luzzadder-Beach et al. Reference Luzzadder-Beach, Beach, Hutson and Krause2016; Kennett and Hodell Reference Kennett, Hodell and Weiss2017), although cenotes penetrating the freshwater lens may encounter saline water (Socki et al. Reference Socki, Perry and Romanek2002). A few shallow lakes also exist in karstic depressions, and reservoirs were constructed into the Early Postclassic period in the Puuc region (Isendahl Reference Isendahl2011). The more southerly coastal plains also had access to fresh water from rivers along those portions secure from seawater intrusion. Given the long-term persistence of drought periods, access to potable water that could serve substantial populations was a distinctive asset (pull factor) for the northern and coastal lowlands, matched in the CML only by the central Petén lakes zone.
The coastal zones of the peninsula also had the advantage of topographic conditions and seawater for salt production, the output of which was part of long-distance trade among the Maya (above) and beyond, even perhaps to the Caribbean Islands (Glover et al. Reference Glover, Rissolo, Mathews and Ford2011; McKillop Reference McKillop, Hofman and Bright2010). Coastal lagoons and marshes favored modification for salt production by way of solar evaporation (Robles Castellanos et al. Reference Robles Castellanos, Andrews, Chuc Aguilar, Masson, Freidel, Demarest, Chase and Chase2020), although “salt kitchens” existed, especially in coastal Belize, where brine spring water and salty soil were cooked to create salt cakes (McKillop and Sills Reference McKillop and Cory Sills2025). The scale of the Maya salt trade and the economic advantages of it were profound (Andrews Reference Andrews1980; McKillop Reference McKillop2021; Robles Castellanos et al. Reference Robles Castellanos, Andrews, Chuc Aguilar, Masson, Freidel, Demarest, Chase and Chase2020), creating a pull factor for occupation in proximity to the waters surrounding the peninsula.
Coastal zones also favored access to sea and riverine food stocks. Seafood helped to supply Postclassic food demands inland in the northern lowlands, as evidenced by fish consumption at Mayapan, about 80 km from the coast (Kennett et al. Reference Kennett, Masson, Serafin, Culleton, Lope, Amber and Gregory2016). The settlements in the coastal plains of the Champotón watershed on the western side of the peninsula consumed seafoods (Ek 2014 ), and the wetlands along the Candelaria River maintained fish farms (Gunn et al. Reference Gunn, Folan, Torrescano-Valle, Faust, Geovannini-Acuña, Siemens, Torrescano-Valle, Islebe and Roy2019). In addition, extensive fish-trapping infrastructure exists along the rivers of the coastal plains to the east of the CML dating to early Maya occupation of the lowlands (Harrison-Buck et al. Reference Harrison-Buck, Krause, Brouwer Burg, Willis, Perrotti and Bailey2024). It would not be surprising, however, to find that such activities existed throughout Maya occupation (Palka Reference Palka2024). Salted fish was traded inland (Alsgaard Reference Alsgaard2020; McKillop and Aoyama Reference McKillop and Aoyama2018), surely serving the CML during its occupation. Nevertheless, lands below the elevated interior and adjacent to the coastlines maintained the advantage of fish commerce, and their populations may have survived physiological stress better than those in the elevated interior (White et al. Reference White, Maxwell, Dolphin, Williams and Longstaffe2006).
Infrastructure
Throughout the Postclassic period, the northern and coastal lowlands sustained settlements, trade and transport, and food production infrastructure that supported a material lifestyle which had long deteriorated in the CML. Among other facilities, a 215 km coastal waterway extended from about Celestún on the northeastern shores of the peninsula to Dzilam de Bravo on the northern shores (Figure 1). This transport use was operative long before, but continued, into the Postclassic period and beyond (Robles Castellanos et al. Reference Robles Castellanos, Andrews, Chuc Aguilar, Masson, Freidel, Demarest, Chase and Chase2020).
In contrast, the sparsely occupied Postclassic CML contained the remnants of its former infrastructure, settlements to landesque capital, and massive forests to be cleared. Reoccupation consistent with a millennium-scale population rebound mimicking the material conditions in the northern and coastal lowlands would have required substantial labor costs. Following Abrams’ (1994) construction energetics, creating CML residential structures only for an occupancy of 25 people per square kilometer (five persons per abode; 5 percent improved or elite structures), yields 126 million labor-days. This figure, however, does not include the substantial costs of constructing monumental architecture, reservoirs, aguadas, sacbes, terraces, and wetland fields, as well as clearing the forest and producing subsistence during the infrastructure rebuild (e.g., Beach et al. Reference Beach, Luzzadder-Beach, Krause, Guderjan, Valdez, Fernandez-Diaz, Eshleman and Doyle2019; Bhattacharya et al. Reference Bhattacharya, Krause, Penny and Wahl2023; Castanet et al. Reference Castanet, Fernandes, Mokadem, Hatté, Gauthier, Develle‐Vincent, Cavero, Dru, Virmoux, Sipos, Dussol and Nondédéo2024; Lucero Reference Lucero2023; Palka Reference Palka2024; Tankersley et al. Reference Tankersley, Dunning, Carr, Lentz and Scarborough2020). Redevelopment over multiple years, however, would have reduced annual labor costs (Webster and Kirker Reference Webster and Kirker1995), and refurbishing decayed landesque capital may have lowered the total labor. The critical push–pull point, however, is the willingness of an emigrant population to give up its existing material lifestyle for a lesser one or for an extended period while creating the infrastructure to provide the material conditions left in the north or along the coasts. Intuitively, this consideration would lead to a low push and low pull for the northern and coastal lowlands and the CML, respectively.
This observation, however, warrants caution. Maya populations had abandoned lands and moved within and into the CML before the Postclassic period (Arnauld et al. Reference Arnauld, Andrieu, Forné, Vapnarsky, de Pierrebourg and Michelet2017). For example, some urban sites in the CML, such as El Mirador (Wahl et al. Reference Wahl, Byrne, Schreiner and Hansen2007), were abandoned near the end of the Preclassic period. Presumably, a sizable portion of these urban folks moved elsewhere in the CML, signaling the need for new or refurbished infrastructural costs. The Itza, of course, migrated from the northern lowlands to Lake Petén Itzá in the Postclassic, constructing Nojpetén as a facsimile of the settlements from which they came (Rice and Rice Reference Rice and Rice2018b). Unfortunately, in both of these cases—CML urban abandonment and the Itza arrival—the time it took to create the amount and quality of infrastructure that was abandoned and the role that this consideration might have played in decisions to move, if any, are not clear.
Comparing factors
The strongest pull factor for substantial immigration into the CML during the Postclassic era would appear to be its superior agricultural conditions—higher quality soils, increased average annual precipitation, and longer growing (wet) season—compared to the northern lowlands and coastal areas, excepting the riverine locations. In addition, the CML incurred fewer intensive tropical storms and possessed substantial amounts of land to be settled. These potential pull factors, however, were insufficient to outweigh the comparative disadvantages of the CML or the low push factors beyond the CML, foremost access to potable water, especially during times of severe drought, and its distance from the critical seagoing commerce.
Critically, the land pressures among Postclassic Maya on the northern plains and, likely, the coastal zones, were not exceptionally high, averaging below 20 people per square kilometer and capable of recovering from environmental hazards. Documented population rebounds invariably followed drought-induced mortality among the northern Maya in the colonial era (Hoggarth et al. Reference Hoggarth, Restall, Wood and Kennett2017). Such rebounds, we suspect, were consistent throughout the Postclassic period. Access to marine and riverine foods surely played a role in this rebound.
In addition to the material conditions examined here, the Postclassic shift to mercantilism and the dominance of seagoing trade provided a huge pull for Maya areas below the elevated interior and in proximity to the coast. Dispersed networks of northern city-states tended to maintain few restrictions on trade, facilitating commercial networks over larger regions (Masson and Freidel 2020 ; Volta et al. Reference Volta, Gunn, Folan, Folan, Braswell, Masson, Freidel, Demarest, Chase and Chase2020). By the thirteenth century, the independent settlements and polities in the north permitted the movement of residents among the settlements (Kennett et al. Reference Kennett, Masson, Lope, Serafin, George, Spencer, Hoggarth, Culleton, Harper, Prufer, Milbrath, Russell, Uc Gonzalez, McCool, Aquino, Paris, Curtis, Marwan, Zhang, Asmerom, Polyak, Carolin, James, Mason, Henderson, Brenner, Baldini, Breitenbach and Hodell2022). Together, these conditions provided safety nets to confront environmental hazards and helped to stabilize occupancy in the northern lowlands.
Expressing it differently from our argument, Demarest (Reference Demarest, Arnauld and Breton2013) proposed that alternative occupational locations—the northern and coastal lowlands—and their conditions were causal factors in the absence of a Postclassic population rebound elsewhere in the greater Yucatán peninsular region, including the CML. This proposal is consistent with the Postclassic push–pull factors examined in our assessment. Granting causality to the presence of alternative occupation zones raises a conundrum, however, as follows. Long before the Postclassic period, the lowland Maya occupied the entire peninsular region, although the population and power levels of the CML were at the apex of the Maya realm. A change in the political economy and shift in trade-route dominance during the Postclassic would understandably lead to occupational shifts consistent with the new conditions. Not so understandable, however, is the radical level of occupation shifts, leaving a nearly vacant CML. Metaphorically, the occupation of Maya realm, not just the CML, from the Classic to Postclassic periods is that of a glass completely full to a glass half empty.
This problem notwithstanding, the archaeological and historical records indicate at least one push factor from the occupied lands to the CML. Major social conflicts triggered migration to the CML and elevated interior at large. Internal Maya conflicts in the northern lowlands pushed the Itza to migrate permanently to the CML (Rice and Rice Reference Rice and Rice2018b), as noted above, incurring the costs of recreating the necessary infrastructure for their occupation. Notably, this level of reoccupation involved an entire lineage returning to its ancestral homelands, pointing to the nuances involved in the migration to and sustained occupation of the CML. Somewhat similarly, Spanish–Maya disagreements and conflicts in the colonial era prompted the flight into, if not permanent occupation of, the elevated interior (Farriss Reference Farriss1984; Jones Reference Jones1990, Reference Jones1998), perhaps reaching the CML. In either case, the CML offered large amounts of unoccupied or sparsely occupied lands and extensive tracts of forests that served as protection from other polities and, eventually, the Spaniards in the north. For those escaping Spanish control, the upland forests provided suitable short-term habitats for occupation with their rested soils and abundant useful tree species, a product of former Maya orchard gardens and managed forests (e.g., Atran et al. Reference Atran, Chase, Fedick, Knapp, McKillop, Marcus, Schwartz and Webb1993; Brokaw et al. Reference Brokaw, Ward, Beach, Luzzadder‐Beach, Walling, Cortes‐Rincon and Valdez2025; Fedick Reference Fedick, Masson, Freidel, Demarest, Chase and Diane2020; Fedick et al. Reference Fedick, Morell-Hart and Dussol2023; Ford Reference Ford2015; Gómez-Pompa et al. Reference Gómez-Pompa, Salvador Flores and Sosa1987; Ross Reference Ross2011; Wyatt Reference Wyatt, Masson, Freidel, Demarest, Chase and Chase2020). Most of the Maya involved in such escape episodes did not remain in the CML, however.
Summary and observations
Evidence of the diversity and complexity of human-environmental relationships in the ancient Maya lowlands continues to increase. Recognizing various challenges to the interpretation of that evidence, the literature is replete with the following narrative. Owing to extreme land pressures and persistent climatic drought during the Late Classic–Terminal Classic periods, the societal conditions of the Maya of the CML, as well as the elevated interior at large, had difficulties maintaining food and water services. Interactive with and amplifying these difficulties was the diminution of economic activities by way of regional trade networks, which overwhelmingly shifted to coastal seafaring. These conditions assisted in a human-environmental transformation—a socio-political collapse, substantial population losses, and a subsequently degraded infrastructural or built environment. Essentially, this transformation mimics the characteristics of a regime shift associated with crossing the tipping point of a system.
The Postclassic demographic focus of the lowland Maya shifted to the northern plains and the Caribbean and Gulf coasts of the peninsular region, those possessing access to drought-resistant water sources. The emergence of a mercantile economy, dominated by seafaring trade, supported a materially prosperous population. Postclassic population pressures, muted by agricultural constraints and drought interludes, apparently did not reach the levels obtained in the CML before its depopulation. The ability of people to move among the occupied polities may have ameliorated societal drought impacts and pressures to move beyond the occupied zones.
We surmise that these dynamics—the conditions leading to the significantly depopulated CML and those of the Postclassic occupied zones—provide insights into the unusual, long-term demographic history of the CML. The pull factors of the environmentally restored and agriculturally superior CML were insufficient to attract major reoccupation, given the low levels of push factors in the Postclassic northern and coastal zones. The immense forests of CML remained primarily intact throughout the Postclassic period, except for the areas immediate to the central Petén lakes. Spanish impacts during the colonial era, including the conquest of the Itza, would continue the low occupancy of the CML, which has extended into the twenty-first century.
The demographic distinctiveness of the CML—the lack of a population rebound, at either two centuries or a millennium—constitutes one of the more unique characteristics of the prehispanic Maya. The evidence of the absence of this rebound has stood the test of time, in contrast to other unique interpretations or claims about the ancient Maya relative to other past agrarian societies. Given this uncommon demographic history, we reiterate our initial question: why has direct research attention to this history been so sparse?
Our attempt to address the topic considers those push–pull factors for which evidence resides in the literature, if not directed to the topic per se. We focused on material factors because the evidence permits quantitative data comparisons, if at a rudimentary level, between the northern and coastal lowlands and the CML. This exercise indicates the need for more robust, fine-tuned analyses based on improved levels of data specification, especially for the Postclassic areas of occupation. Examples include population pressures, which involve more than raw population densities, agricultural output for different soils and management strategies, water access for settlements in which groundwater-cenotes and -caves and river access did not exist, and fine-tuned, locational intensities of drought and hurricane impacts. With sufficient specification, these and other factors may improve our understanding of the topic by way of various modeling approaches, with attention to the use of geographically weighted regressions to account for the role of location in push–pull factors.
Finally, our attention to nonmaterial push–pull factors has been sparse. We briefly addressed the willingness of the populations of the well-developed Postclassic occupational areas to give up their material lifestyle to migrate to the forested CML and recreate it through infrastructure development. We also recognized the transformation of the political economy from the Classic to Postclassic periods, but did not pursue why such a change would alter the occupation of the Maya realm so fundamentally. Why would the political and economic structures before the Postclassic period produce occupation throughout the entirety of the Maya realm, whereas those during the Postclassic period lead to large areas with minimal population? More sophisticated assessments of these and other nonmaterial factors, such as sociocultural dimensions and power dynamics among the Maya, are warranted. We encourage those steeped in these dimensions and dynamics of Maya studies to add them to future assessments.
Improved understanding of the uncommon demographic history of the CML should provide insights into other important queries that require the attention of the research community. Paramount among these is the reason for the prosperity and power of the CML before the Terminal Classic period, given its subsequent status. Did it reside in the favorable agricultural base of the CML, the social dynamics of its inhabitants, the legacy and lock-ins of its abandonment, or other human-environmental conditions?
Acknowledgements
We think Jeremy Sabloff for comments on earlier drafts of this paper, and Timothy Beach and Arlen Chase for providing access to various literatures. The reviewers of the initial submission of this paper provide critical insight that directed alterations. The authors are responsible for the content of the paper, however. The Gilbert F. White Professorship, Arizona State University provided financial support for the publication. We thank Shea Lemar and Yueling Li for the preparation of Figure 1.
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