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Three scenarios of colonizing metapopulations. a, Bold colonization by jump dispersal. Here, some groups (black circles) at the edge of a metapopulation take the risk of jumping across an area of low productivity (e.g., a desert or open sea) to find a better area than their present location. Although the risk of failure is high, success means that a new region can be colonized by descendant groups (white circles). b, Colonization and assimilation. In this scenario, part of a metapopulation (A; black circles) begins to invade an area occupied by a different type of hominin, shown as MF, with M p males and F p females. The invasive metapopulation then proceeds to assimilate the females of reproductive age (B), thus degrading the previous viability of the indigenous population. This type of scenario is indicated by evidence of gene flow from Neanderthals and Denisovans into Homo sapiens outside Africa and may also help explain the evidence for hybridization in the East Asian skeletal evidence for H. sapiens between marine isotope stage (MIS) 5 and MIS 3. c, Colonization and population replacement. Here, a metapopulation (black circles) begins to invade an area already occupied by other groups (open circles). In B, the indigenous occupants are replaced. This process may have been violent but may also have occurred because the incoming population outcompeted the local population for key resources and locations and destroyed their connectivity between groups. This scenario is one explanation for the replacement of Neanderthals by H. sapiens in western Eurasia.
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Narratives of “Out of Africa 2”—the expansion of Homo sapiens across Asia—emphasize the pattern of human dispersal but not the underlying processes. In recent years, the main debates have been over the timing and frequency of dispersal. Here, I treat these issues as subordinate to biogeographic ones that affected the behavior of humans in Asia as a...
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Context 1
... colonists are ones that move when productivity declines. These colonists inhabit areas that will not support long-term residence of the kind favored by cautious colonists, so they have a high incentive to move, and especially to "jump" across areas that are low in productivity (such as steppe or deserts; see fig. 5a). During sudden environmental downturns, for example, water resources might diminish and game be- come less plentiful; onward movement to new areas thus be- comes risky, but it is nevertheless less risky than clinging to a declining resource base. Bold colonists tend to use mobility to explore and become familiar with large areas (Veth ...
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... sexual relations between colonizer and colonized were overwhelmingly be- tween European males and native females (see, e.g., Hyam 1991;Walter 2010). As a speculation, interbreeding between H. sapiens and Neanderthals and Denisovans may also have been largely between invasive male H. sapiens and indigenous female Neanderthals and Denisovans (see fig. ...
Context 3
... least four other scenarios of human-indigenous inter- action can be envisaged: (1) taking over the indigenous species' habitat by, for example, more effective hunting of prime animals, preemptive use of key locations, and aggressive be- havior toward the inhabitants (see fig. 5c); (2) coexisting but with little interaction; (3) occupying parts of the landscape (such as coastal regions) that were seldom used by indigenous groups (see Shigesada and Kawasawki 1997:104); and (4) in- troducing new diseases into Asia that were lethal to indigenous residents (Bar-Yosef and Belfer-Cohen 2001), just as, in recent ...
Citations
... Southwest Asia, a key region in hominins dispersion out of Africa, has long been integral to any reconstructions of the related dispersal patterns (Bar-Yosef & Belfer-Cohen, 2001;Dennell & Roebroeks, 2005;Dennell, 2010;Dennell, 2017;Dennell, 2020;Groucutt et al., 2021). In this context, the Iranian plateau becomes all the more important given its proximity, in particular its southern quarter, to the Arabian Peninsula that served as a bridge and corridor for hominin movements in the Pleistocene period from eastern Africa to the Indian subcontinent and the central Asian plains (Vahdati Nasab et al., 2013). ...
... Begging the question: 'Who is the invader?' (Elton 1958). While this remains scientifically contested, in fact we -Homo sapiens -could be considered invasive alien species number one on this planet (Marean 2015;Dennell 2017). ...
This introduction begins at the Bruges 2018 Triennial Liquid City, where the research and design collective Rotor, the Ghent Centre for Global Studies, and Anna L. Tsing organised an interdisciplinary workshop on the trajectories of displaced species. Looking back to the collaborative reflection that emerged during the workshop, and the pandemic since, this special issue recalls invasive species from within the broader field of multispecies research. It proposes a relational, entangled approach to expose and examine the contradictions and instabilities that shape the more-than-human entanglements through which humans recasts certain non-humans as ‘invasives’. Interweaving the journeys of crabs, moles, rabbits, and fungi in and out of human-designed worlds, this article formulates three sets of guiding questions for the special issue. Our questions inquire into the conceptual and scientific frameworks, the material infrastructures, and the repertoires of human reactions to disturbances, exposing how species invasion initiates relations of correspondence that exceed categories of ‘invasiveness’.
... Population dynamics start from the establishment of ''source'' and ''sink'' populations (Dennell, 2017b;Dennell et al., 2011). In this ecological approach to source-sink populations, human populations can then form ''metapopulations'' (sensu Smith, 2013), which can be defined as ''a group of spatially separated populations that occupy a set of favorable habitat patches''. ...
People were in the Americas before, during, and immediately after the Last Glacial Maximum. Multiple data converge toward a deep chronology model for Homo genre exploration, dispersal, occupation, and settlement across the continent. South America is not an exception. This paper is an attempt to think of South America record in terms of population dynamics within a Paleolithic reflection: What are the anthropological implications of a longer and therefore slower peopling process? What modes of expansion, rhythms, adaptations, routes could be traced base especially in lithic records? What kind of archaeological manifestations should we expect in the different environments that make up an immense and highly diverse geography? What modes of technological continuity and change could be linked to these manifestations? Although further research is still needed to address these questions, our goal is to contribute to posing the problem in the most holistic way possible, linking climate, environment, and techno-cultural data within and beyond South America, in order to model how populations might have expanded and contracted at different periods throughout this subcontinent.
... lithics). Given the assumption of Late Pleistocene population expansion into east through SCC, this area might have been highly populated at the warm and moist stages of MIS 5 [50] and later as refugium during MIS 4 [37,38,115] when between 50 and 45 ka the Ust'-Ishim man lived in western Siberia [116]. The genomic history of the Ust'-Ishim man shows that the admixture between the ancestors of the Ust'-Ishim and Neanderthals occurred PLOS ONE between ca. ...
The study of the cultural materials associated with the Neanderthal physical remains from the sites in the Caucasus, Central Asia and Siberian Altai and adjacent areas documents two distinct techno-complexes of Micoquian and Mousterian. These findings potentially outline two dispersal routes for the Neanderthals out of Europe. Using data on topography and Palaeoclimate, we generated computer-based least-cost-path modelling for the Neanderthal dispersal routes from Caucasus towards the east. In this regard, two dispersal routes have been identified: A northern route from Greater Caucasus associated with Micoquian techno-complex towards Siberian Altai and a southern route from Lesser Caucasus associated with Mousterian towards Siberian Altai via the Southern Caspian Corridor. Based on archaeological, bio- and physio-geographical data, our model hypothesises that during climatic deterioration phases (e.g. MIS 4) the connection between Greater and Lesser Caucasus was limited. This issue perhaps resulted in the separate development and spread of two cultural groups of Micoquian and Mousterian with an input from two different population sources of Neanderthal influxes: eastern and southern Europe refugia for these two northern and southern dispersal routes respectively. Of these two, we focus on the southern dispersal route, for it comprises a 'rapid dispersal route' towards east. The significant location of the Southern Caspian corridor between high mountains of Alborz and the Caspian Sea, provided a special biogeographical zone and a refugium. This exceptional physio-geographic condition brings forward the Southern Caspian corridor as a potential place of admixture of different hominin species including Neanderthals and homo sapiens.
... Ma), although most records of the activity of early hominins is found in caves of this period (Wang et al., 2007). These hominins are thought to have been Homo erectus, who had more limited ability in seeking food, transporting water, and adapting to a variable environment relative to H. sapiens (Groucutt et al., 2015;Dennell, 2017). Abundant stone implements, including chopper, handpick, scraper, and burnisher were presented in the upper Gaolingpo profile with an age of ~0.2 Ma. ...
The Quaternary river sediments at Gaolingpo, Bose Basin, Guangxi Province contain stone hand adzes and microliths of Paleolithic and Neolithic ages, providing information about the effect of climatic and environmental changes on hominin and early modern human activities. Gaolingpo is a representative Paleolithic site in the Bose Basin, containing numerous stone artifacts of different ages in the red earth sediments. We examined the clay mineralogy and geochemistry of the Gaolingpo profile using X-ray diffractometry (XRD), diffuse reflectance spectroscopy (DRS), and X-ray fluorescence (XRF) spectroscopy with the goal of reconstructing paleoclimatic and environmental changes in the study area since the late Early Pleistocene. Within this soil profile, kaolinite and vermiculite increase and illite decreases gradually up section. The red earth sediments exhibit uniform chondrite-normalized rare earth element (REE) distribution patterns, which are similar to those of upper continental crust (UCC), post-Archean Australian shale (PAAS), loess and paleosol of the Chinese Loess Plateau (CLP), and Yangtze River deposits. These confirm that the Gaolingpo red earth sediments originated from fine materials of well-mixed weathered continental crust within the upper Pearl River drainage basin. The chemical index of alteration (CIA) of the Gaolingpo sediments is 86.4–92.1, indicating that the sediments have undergone intense chemical weathering. Based on changes in clay mineral contents and geochemical compositions through the profile, the paleoclimatic evolution of the Gaolingpo area since the late Early Pleistocene can be divided into two stages with four sub-stages: (1) a generally humid climate prevailed during stage I can be further divided in two sub-stages. Sub-stage Ia was temperate with an alternating dry and wet climate, while sub-stage Ib was a transition to a warmer temperate climate. (2) A subtropical humid climate prevailed during stage II and transitioned to a cooler climate in the later stage. In this episode, sub-stage IIa was the warmest and the most humid period since the late Early Pleistocene in Bose Basin, and Stage IIb was a transition to a relatively cooler subtropical climate. This climate pattern is compatible with the regional palynological record at Chongzuo, south Guangxi and is in general agreement with the δ¹⁸O records from cave stalagmites in southern China, but is inconsistent with the δ¹⁸O record at ODP Site 1148 in the northern part of the South China Sea, though the age constraints limit a precise correlation. This reflects the predominant influence of Qinghai-Tibetan Plateau uplift on East Asian climate since the late Early Pleistocene. The development of warm, humid, and only weakly fluctuating climate conditions in the Bose Basin was favorable for early hominin settlement.
... This conclusion follows the same logic as above, insofar as the H. floresiensis and H. luzonensis fossil occurrences are feasibly generated by the same processes as those that led to other fossil hominin occurrences in Java and China. Geographic, topographical and ecological factorsincluding the presence of the Wallace Linemay still support the suggestion that the islands (and wider region) acted as refugia (Louys and Turner, 2012;Stewart and Stringer, 2012;Dennell, 2017;Zachwieja et al., 2020). ...
The presence of Homo floresiensis and Homo luzonensis in southeast Asia 90,000 to 60,000 years ago is considered surprising by many, and has been used to support their designation as unique species and the islands they were discovered on as refugia. Here, we statistically test the null hypothesis that H. floresiensis and H. luzonensis represent temporally uninterrupted occurrences relative to Homo erectus. We do this using the 'surprise test' for the exceptionality of a new record. Results demonstrate that H. floresiensis and H. luzonensis are not temporally distinct relative to H. erectus. Their late persistence should, therefore, not be considered surprising, they cannot reliably be inferred to be outside of H. erectus' temporal range, and-temporally-the islands of Luzon and Flores are not supported as refugia. Similarly, late H. erectus at Ngandong, Java, is not demonstrated to be temporally distinct relative to earlier, principally mainland-Asian, H. erectus. Further, we demonstrate that substantial numbers of fossil discoveries would be needed before H. floresiensis and H. luzonensis are outside of H. erectus' expected temporal range. If H. floresiensis and H. luzonensis are descended from H. erectus populations, our results point toward either geographic processes of allopatric speciation or behavioural processes leading to a sympatric speciation event.
... The pattern we have identified of repeated movements of people and ideas from a population and innovation core area in SE Fennoscandia to the periphery of the northern Norwegian coast, closely aligns with the process conceptualized by "source-sink" dynamics. The S/S framework is increasingly being used to understand the biogeography of human dispersals, typically a slow and intermittent process e the dynamic involves a population in a patch of mean surplus productivity growing until it eventually spills out individuals who move into empty or less densely packed regions with lower productivity (Dennell, 2017(Dennell, , 2020Dennell et al., 2011;Lamb et al., 2017;Robertson and Hutto, 2006). ...
What drives the adoption of pottery amongst prehistoric foragers in high-latitude environments? Following the long-running interests of archaeology in explaining the origin and dispersal of new technologies, recent years have seen growing efforts to understand what drove the emergence and expansion of early hunter-gatherer pottery use across northern Eurasia. However, many regional dimensions to this continental-scale phenomenon remain poorly understood. Initial pottery adoption has often been explained as a generic cultural response to warming climates and the growing diversity of food resources, yet resolving challenges of food security during seasonal shortfalls or general climatic downturns may have provided alternative motivations. It is also becoming clear that many regions experienced more complex patterns of pottery adoption and that many resist simplistic monocausal interpretations. In this paper we deploy a Human Ecodynamics framework to examine what drove the punctuated adoption of two early pottery traditions into Arctic Maritime Europe, which were separated by a multi-millennial ceramic hiatus – Early Northern Comb Ware (ENCW) and Asbestos Tempered Ware (ATW). Our multi-proxy approach involves the revision of pottery chronologies to clarify the timing and ecological context for each dispersal, combined with analysis of technological and functional dimensions of the ceramic traditions to understand the contrasting social organization of these technologies. Our results confirm that ENCW expanded at a time of increased locational investment and ecological abundance in the region, while ATW spread in a series of smaller and more intermittent waves in the context of a major ecological downturn and alongside a return to a high-mobility lifestyle. Finally, we use the concept of “source-sink dynamics” to suggest that both dispersals were driven by the same underlying process. This involved major climatic fluctuations triggering small-scale population transfers from lake and riverine settings of western Russia, Finland and the Eastern Baltic region via interior areas and through to the Arctic Norwegian coastline, a persistent process that is also well-documented in later historical periods. Our results highlight the crucial importance of bridging-scale case studies as these have the “unsettling” potential to highlight deeper problems of equifinality. In this case, they reveal that two broadly similar material traditions spread into the same regions, albeit in the context of strikingly different environmental and behavioural conditions.
... In our study, if the greater propensity for exploration or foraging in northern populations relates to greater dispersal, it is possible that historical founders from these populations (located north of the historical sub-glacial refugia; Lee-Yaw et al., 2008) contributed to the vast post-Pleistocene movement of wood frogs northward to the Arctic Circle. Similarly, it has been hypothesized that northward post-Pleistocene movement of humans was driven by greater boldness and exploratory tendencies of migrating populations (Dennell, 2017). Looking toward the future, geographic variation in behaviors related to dispersal could greatly affect how animal species ranges respond to warming climates (Seaborn et al., 2020) and inform conservation or management efforts aimed to protect amphibians vulnerable to global climate and land-use change (Joly, 2019;Walls and Gabor, 2019). ...
We assessed the macrogeographic and neuroendocrine correlates of behavioral variation exhibited by juveniles, an important life stage for dispersal, across the expansive range of the wood frog. By rearing animals from eggs in a common garden then using a novel environment test, we uniquely demonstrated differential expression of juvenile behaviors among 16 populations spanning 8° latitude. On the individual level, cluster analysis indicated three major behavior profiles and principal component analysis resolved four unique axes of behavior, including escape, foraging, food intake, feeding efficiency. We found that increased escape behavior was associated with lower adrenocorticotropic hormone (ACTH)-induced circulating corticosterone (CORT) levels, however, foraging and food intake behaviors were not associated with either resting or ACTH-induced CORT. At the population level, the expression of foraging behaviors increased with latitude while food intake behaviors declined with latitude, which raised several hypotheses of eco-evolutionary processes likely driving this variation. Given that these behaviors covary along the same ecological gradient as locally adapted developmental traits, genomic studies in this species could provide deep insights into how HPA/I activity is associated with the eco-evolutionary processes that structure intraspecific variation in morphology and behavior.
... In the Tibetan plateau, before the advent of the Holocene, early seasonal forays by mobile foragers into the highlands most likely were a byproduct of the evolution of the Early-and Late Upper Palaeolithic adaptations in the margins of the high plateau, equivalent to the high-altitude zones of Southwest Asia Madsen et al., 2006;see Brantingham et al., 2001). From an environmental constraints point of view, high altitudes (areas above 3000 m.a.s.l) of Asia during the Late Pleistocene (before the terminal Pleistocene), due to the high-frequency fluctuations of the Last Glacial Cycle (~10 to 110 ka) (Thompson et al., 1997) and also deserts have been serious biogeographic obstacles to human expansion/settlement (Dennell, 2017). This situation also appears in Pamir/-Tien Shan where aridity and changes in faunal and floral communities occurred during the Late Cenozoic (Vishnyatsky, 2004, see also Rybin and Khatsenovich 2020). ...
This paper presents evidence for some of the highest-altitude Middle Palaeolithic land-use in southwest Asia identified through field surveys in the Miankouh region of the Bakhtiari highlands within the Zagros Mountains of Iran. Through identification of two vertically connected but distinct ecozones, patterned distribution of stone tool production and use suggests more complex seasonal mobility and land-use patterns than hitherto recognised.
... During the nineteenth and early twentieth centuries, the processes of language legitimation, social selection through education, and the construction of pathways to citizenship were introduced, through education, into the colonial regimes established by European nation-states in different parts of the world -in South America, Africa, and Asia (Cusicanqui et al., 2016;Dennell, 2017;Thiong'o, 1994). In this way, Spanish was established as the language with the greatest symbolic power during the colonial era and then, in the post-colonial era, in the Republic of Colombia (García León & García León, 2012;Triana, 1998). ...
