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Abstract

Late Pleistocene sedimentary, biogeochemical, and fossil data from the Lake Victoria basin (the largest lake in Africa) suggest that its reduction or desiccation during periods of increased aridity repeatedly facilitated the dispersal of C4 grassland ecosystems across the basin. Archaeological evidence from Middle Stone Age and Later Stone Age sites suggest that human groups diffused into the basin during intervals of declining lake levels, likely tracking the movement of the dense and predictable resources of shoreline environments, as well as the dense but less predictable C4 grass grazing herbivores. Repeated cycles of lake expansion and contraction provide a push–pull mechanism for the isolation and combination of populations in Equatorial Africa that may contribute to the Late Pleistocene human biological variability suggested by the fossil and genetic records. Latitudinal differences in the timing of environmental change between the Lake Victoria basin and surrounding regions may have promoted movements across, within, and possibly out of Africa.

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... The Lake Victoria Basin in western Kenya is one of the few places in eastern Africa to yield well-sampled Late Pleistocene paleontological assemblages (e.g., Tryon et al., 2010Tryon et al., , 2016Faith et al., 2015). ...
... The natural vegetation would have included belts of bushland, thicket, and wooded grasslands within ∼10-50 km from the shoreline, transitioning to Afromontane rainforest in the highlands further inland (to the east) (White, 1983;van Breugel et al., 2015). Substantial changes in vegetation structure are implied by the Late Pleistocene faunas, which are dominated by alcelaphin antelopes, equids, and other open-habitat grazers, collectively indicating an expansion of semi-arid grasslands Tryon et al., 2016). Estimates of annual precipitation derived from geochemical analysis of paleosols (∼750-1,000 mm/yr) imply a reduction in rainfall relative to the present-day (∼1,400 mm/yr) (Beverly et al., 2015a(Beverly et al., , 2017, with a recent water-budget model indicating that this would lead to desiccation of Lake Victoria (Beverly et al., 2020). ...
... The position of the Menengai Tuff indicates a maximum age of 36 ka for the Kibogo fossil assemblage, which is corroborated by associated artifacts from the site. The Late Pleistocene sediments in the eastern Lake Victoria Basin are almost exclusively associated with MSA artifacts (e.g., Pickford, 1982Pickford, , 1986Tryon et al., 2016). However, at Kibogo, abundant Later Stone Age (LSA) artifacts, including blades, blade cores, and backed microliths, occur in stratigraphic association with the fauna. ...
Article
We report on the Late Pleistocene (36-12 ka) mammals from Kibogo in the Nyanza Rift of western Kenya, providing (1) a systematic description of the mammal remains, (2) an assessment of their paleoenvironmental implications, and (3) an analysis of the biogeographic implications of non-analog species associations. Kibogo has yielded one of the largest paleontological assemblages from the Late Pleistocene of eastern Africa, and it is dominated by grassland ungulates (e.g., equids and alcelaphin antelopes), including an assortment of extralimital (e.g., Equus grevyi, Ceratotherium simum, Redunca arundinum) and extinct species (Syncerus antiquus, Damaliscus hypsodon, Megalotragus sp.). The composition of the fauna, in conjunction with the soils and topography of the region, indicate the local presence of edaphic grassland situated within a broader environment that was substantially grassier and likely drier than at present. In contrast to non-analog faunas from higher latitudes (e.g., North America and western Eurasia), the climatic niches of non-analog species associations strongly overlap, indicating that non-analog climate regimes during the Late Pleistocene of eastern Africa are not necessary to account for the former association of presently allopatric species. The Kibogo faunas add to a growing body of evidence implying that the composition of present-day African herbivore communities is distinct from those of the geologically recent past.
... For example, from~36 to 94 ka and 14 to 17 ka, at least Lake Victoria, the dominant water feature of the region, had either dried up completely or was substantially reduced in size, changing what is now a lake habitat to an extensive Serengeti-like grassland dominated by extinct and often strikingly distinctive animal communities ( Figure 4). 44,45 The rainforest is also subject to extensive contraction, fragmentation, or expansion caused by increases or decreases in rainfall 46 that may have contributed to intermittent hominin occupation of its margins. 44 Nearshore islands such as Zanzibar appear to have been occupied as early as the LGM~18-26 ka, possibly aided by lowered sea level. ...
... 44,45 The rainforest is also subject to extensive contraction, fragmentation, or expansion caused by increases or decreases in rainfall 46 that may have contributed to intermittent hominin occupation of its margins. 44 Nearshore islands such as Zanzibar appear to have been occupied as early as the LGM~18-26 ka, possibly aided by lowered sea level. 47,48 Although taxonomically dominated by extant taxa (Table 1), fossil fauna at a number of archeological sites indicate generally more arid conditions throughout the region for much of the Late Pleistocene. ...
... East Africa is a useful region to study because of its relatively large number of archeological sequences that sample the MSA/LSA transition, 11 including Enkapune ya Muto, 10 Kisese II, 7 multiple sites at Lukenya Hill, 13,50 Magosi, 51 Magubike, 8,52 Mtongwe, 53 Mumba, 6,12,54,55 Nasera, 9,12,21 Panga ya Saidi, 16 and Shurmai 56 ; individual MSA and LSA sites in the Lake Victoria basin, 44 Olduvai Gorge, 57 and Kuumbi Cave 47,48,58 provide additional constraints on the transition but lack extensive stratigraphic sequences or large sample sizes sufficient to assess change over time ( Table 2) The strongest archeological data set available for this is the distribution of obsidian artifacts that can be tied to a known geological origin, which serves to outline the social limits of past populations who used this common source. 66 Obsidian is volcanic glass. ...
Article
The Middle to Later Stone Age (MSA/LSA) transition is a prominent feature of the African archeological record that began in some places ~30,000–60,000 years ago, historically associated with the origin and/or dispersal of “modern” humans. Unlike the analogous Middle to Upper Paleolithic transition in Eurasia and associated Neanderthal extinction, the African MSA/LSA record remains poorly documented, with its potential role in explaining changes in the behavioral diversity and geographic range of Homo sapiens largely unexplored. I review archeological and biogeographic data from East Africa, show regionally diverse pathways to the MSA/LSA transition, and emphasize the need for analytical approaches that document potential ancestor‐descendent relationships visible in the archeological record, needed to assess independent invention, population interaction, dispersal, and other potential mechanisms for behavioral change. Diversity within East Africa underscores the need for regional, rather than continental‐scale narratives of the later evolutionary history of H. sapiens.
... The situation is however better in East Africa where there are a few well-dated stratified sites that offer diachronic insights into the technological and cultural dynamics of the late Middle and Upper Pleistocene. These few archaeological sites are known from Mumba Gliganic et al. 2012;Mehlman 1989;Prendergast et al. 2007;Tryon et al. 2015), Magubike Willoughby 2012;Willoughby et al. 2018;Tryon and Faith 2013), Nasera (Mehlman 1989;Tryon et al. 2015;Faith 2016), Loiyangalani (Maillo-Fernandes et al. 2019), and Kisele II (Mehlman 1989;Tryon et al. 2018), all in Tanzania. The MSA sites are also present in Enkapune Ya Muto (Ambrose 1998;Tryon et al. 2015;Tryon and Faith 2013), Lukenya Hill (Tryon et al. 2015), Panga ya Saidi (Shipton et al. 2018), andProspect Farm (Van Baelen et al. 2019) in Kenya. ...
... The situation is however better in East Africa where there are a few well-dated stratified sites that offer diachronic insights into the technological and cultural dynamics of the late Middle and Upper Pleistocene. These few archaeological sites are known from Mumba Gliganic et al. 2012;Mehlman 1989;Prendergast et al. 2007;Tryon et al. 2015), Magubike Willoughby 2012;Willoughby et al. 2018;Tryon and Faith 2013), Nasera (Mehlman 1989;Tryon et al. 2015;Faith 2016), Loiyangalani (Maillo-Fernandes et al. 2019), and Kisele II (Mehlman 1989;Tryon et al. 2018), all in Tanzania. The MSA sites are also present in Enkapune Ya Muto (Ambrose 1998;Tryon et al. 2015;Tryon and Faith 2013), Lukenya Hill (Tryon et al. 2015), Panga ya Saidi (Shipton et al. 2018), andProspect Farm (Van Baelen et al. 2019) in Kenya. ...
... These few archaeological sites are known from Mumba Gliganic et al. 2012;Mehlman 1989;Prendergast et al. 2007;Tryon et al. 2015), Magubike Willoughby 2012;Willoughby et al. 2018;Tryon and Faith 2013), Nasera (Mehlman 1989;Tryon et al. 2015;Faith 2016), Loiyangalani (Maillo-Fernandes et al. 2019), and Kisele II (Mehlman 1989;Tryon et al. 2018), all in Tanzania. The MSA sites are also present in Enkapune Ya Muto (Ambrose 1998;Tryon et al. 2015;Tryon and Faith 2013), Lukenya Hill (Tryon et al. 2015), Panga ya Saidi (Shipton et al. 2018), andProspect Farm (Van Baelen et al. 2019) in Kenya. The list also includes Butcha (Leplongeon 2014;Pleurdeau et al. 2014;Tribolo et al. 2017) and Porc Epic (Assefa et al. 2008;Rosso et al. 2014, Rosso et al. 2017 in Ethiopia as well as Laas Geel shelter 7 in Somaliland (Gutherz et al. 2014). ...
Article
Full-text available
Although anatomically modern humans emerged during the MSA, debates have focused on the timing for the development of cognitive thoughts, planning depth, and profound cultural innovations. While some scholars have attributed these qualities to the LSA population, others have proposed that the evolutionary modern human behaviors developed during the MSA. This paper is a contribution to this debate based on new excavations at Mumba site, Tanzania, occupied at different periods from the last Interglacial Maximum around 128,000 BP through the onset of Holocene ca. 12,000 BP. We use new ESR dates, geochronology of stratigraphic sequences, lithic technology and typological variability in archaeological assemblages to show gradual transformation, steadiness, and shared technological traits between the MSA and LSA occupation levels at Mumba. We concluded that there are no fixed boundaries between the late MSA and early LSA regarding cognitive thought and technological transformation in Africa.
... Researchers have only recently begun to understand the late Pleistocene faunas of eastern Africa, despite their critical role for interpreting the paleoenvironmental context of a time and place central to the diversification and dispersal of early modern humans (Homo sapiens) Scerri et al., 2018;Tryon, 2019). The late Pleistocene large mammal communities were composed of numerous extinct taxa, some of which were dominant members of the region's faunas until the onset of the Holocene (MacInnes, 1956;Marean and Gifford-Gonzalez, 1991;Marean, 1992;Faith, 2014;Faith et al., 2015;Lesur et al., 2016;Tryon et al., 2016). This emerging perspective has been reinforced by ongoing research in the Kenyan portions of the Lake Victoria Basin since 2008, which has documented numerous extinct taxa (Rusingoryx atopocranion, Damaliscus hypsodon, Kolpochoerus, and others) in late Pleistocene sediments, including new species or those formerly thought to have disappeared from eastern Africa during the middle Pleistocene (e.g., Tryon et al., 2010Tryon et al., , 2012Tryon et al., , 2016Faith et al., 2011Faith et al., , 2014Faith et al., , 2015Jenkins et al., 2017). ...
... The late Pleistocene large mammal communities were composed of numerous extinct taxa, some of which were dominant members of the region's faunas until the onset of the Holocene (MacInnes, 1956;Marean and Gifford-Gonzalez, 1991;Marean, 1992;Faith, 2014;Faith et al., 2015;Lesur et al., 2016;Tryon et al., 2016). This emerging perspective has been reinforced by ongoing research in the Kenyan portions of the Lake Victoria Basin since 2008, which has documented numerous extinct taxa (Rusingoryx atopocranion, Damaliscus hypsodon, Kolpochoerus, and others) in late Pleistocene sediments, including new species or those formerly thought to have disappeared from eastern Africa during the middle Pleistocene (e.g., Tryon et al., 2010Tryon et al., , 2012Tryon et al., , 2016Faith et al., 2011Faith et al., , 2014Faith et al., , 2015Jenkins et al., 2017). These new data show that Homo sapiens in eastern Africa evolved among non-analog faunal communities (e.g., Faith et al., 2016), as has long been recognized for southern Africa (e.g., Klein, 1980). ...
... The Bovid Hill assemblage thus affords a rare opportunity to provide a more holistic understanding of its ecology. In addition to the bonebed accumulation at Bovid Hill, remains of the alcelaphin bovid Rusingoryx have been recovered from other late Pleistocene sediments (∼100-36 ka) around the Kenyan Lake Victoria Basin, including both Rusinga and Mfangano islands and mainland sites Luanda West and Karungu (Faith et al., 2011;O'Brien et al., 2016;Tryon et al., 2016;Blegen et al., 2017;Jenkins et al., 2017). ...
Article
Rusingoryx atopocranion is an extinct alcelaphin bovid from the late Pleistocene of Kenya, known for its distinctive hollow nasal crest. A bonebed of R. atopocranion from the Lake Victoria Basin provides a unique opportunity to examine the nearly complete postcranial ecomorphology of an extinct species, and yields data that are important to studying paleoenvironments and human-environment interaction. With a comparative sample of extant African bovids, we used discriminant function analyses to develop statistical ecomorphological models for 18 skeletal elements and element portions. Forelimb and hin-dlimb element models overwhelmingly predict that R. atopocranion was an open-adapted taxon. However, the phalanges of Rusingoryx are remarkably short relative to their breadth, a morphology outside the range of extant African bovids, which we interpret as an extreme open-habitat adaptation. It follows that even recently extinct fossil bovids can differ in important morphological ways relative to their extant counterparts, particularly if they have novel adaptations for past environments. This unusual phalanx morphology (in combination with other skeletal indications), mesowear, and dental enamel stable isotopes, demonstrate that Rusingoryx was a grassland specialist. Together, these data are consistent with independent geological and paleontological evidence for increased aridity and expanded grassland habitats across the Lake Victoria Basin.
... An exceptionally high degree of confidence in tephra correlation can be established for the Menengai Tuff based on the common presence of distinctive brown shards, the common bimodality of its glass composition in the majority of samples, and the distinct composition of either of these two compositional modes when compared to the major element chemistry of every other published volcanic ash in the Pliocene through Holocene of East Africa (Brown and Cerling, 1982;Brown and Fuller, 2008;Brown et al., 1992;Feakins and Brown, 2007;Haileab and Brown, 1992;Pickford et al., 1991;Sarna-Wojcicki et al., 1985;Tryon, 2003;McBrearty, 2002, 2006). This includes all known chronological and compositionally similar tuffs such as the Nyamsingula and Nyamita Tuffs known from the Late Pleistocene exposures of the eastern Lake Victoria Basin, an area of currently active tephra research in equatorial Kenya (Blegen et al., 2015;Tryon et al., 2016). We include samples of the Nyamita and Nyamsingula Tuffs of the eastern Lake Victoria Basin, western Kenya because these tuffs are chronologically, stratigraphically and chemically defined in recent publications (Blegen et al., 2015;Tryon et al., 2016) and are found in stratigraphic sequence with samples of the Menengai Tuff included in this study. ...
... This includes all known chronological and compositionally similar tuffs such as the Nyamsingula and Nyamita Tuffs known from the Late Pleistocene exposures of the eastern Lake Victoria Basin, an area of currently active tephra research in equatorial Kenya (Blegen et al., 2015;Tryon et al., 2016). We include samples of the Nyamita and Nyamsingula Tuffs of the eastern Lake Victoria Basin, western Kenya because these tuffs are chronologically, stratigraphically and chemically defined in recent publications (Blegen et al., 2015;Tryon et al., 2016) and are found in stratigraphic sequence with samples of the Menengai Tuff included in this study. The general chemical similarities of the trachytic and phonolitic Nyamita and Nyamsingula Tuffs to the Menengai Tuff are useful as 'out-groups' for visual display in bivariate plots and numerical comparison in SC analysis when defining the distinct nature of the Menengai Tuff. ...
... We analyze nine Late Pleistocene fossil ungulate assemblages from Rusinga Island, Mfangano Island, and Karungu in the Lake Victoria Basin of western Kenya (Tryon et al., 2010(Tryon et al., , 2012(Tryon et al., , 2016Faith et al., 2015) (Fig. 1; Table 1). These assemblages were surface-collected during the course of systematic paleontological surveys, with collection protocol emphasizing recovery of cranial and dental remains, as well as taxonomically informative postcrania (i.e., any element that could be assigned to genus). ...
... These assemblages were surface-collected during the course of systematic paleontological surveys, with collection protocol emphasizing recovery of cranial and dental remains, as well as taxonomically informative postcrania (i.e., any element that could be assigned to genus). The fossil samples are derived from localities with Late Pleistocene sediments dating from~100 to 36 ka that are correlated to each other on the basis of shared tephra Faith et al., 2015;Tryon et al., 2016). Alcelaphin bovids and equids numerically dominate the assemblages, indicating an open grassland distinct from the evergreen bushland, thicket, and forest habitats historically present in the region. ...
Article
Ecometric analysis involves the examination of quantifiable functional traits across the taxa in a biotic community. Well-documented relationships between certain functional traits and environmental gradients in the present provide the empirical framework for a large body of research that uses ecometrics to reconstruct environments in the fossil record. In current applications of the technique, the taxa present in a fossil assemblage are summarized using the mean value of an environmentally informative trait. This study explores some of the quantitative pitfalls inherent to this approach. Through analysis of dental crown height—a trait that is widely used to infer paleo-precipitation—of Late Pleistocene ungulate assemblages from the Lake Victoria Basin in western Kenya, we illustrate how ecometric means vary as a function of sample size. Sampling artifacts have the potential to bias ecometric means, and the environmental inferences derived from them, whenever there is a non-random distribution of traits across the species abundance distribution (e.g., if abundant taxa have different traits than rare taxa). This sampling issue also means that the degree of analytical precision implied by quantitative paleoenvironmental reconstructions (e.g., annual precipitation at time X was 500 mm/yr) derived from ecometrics may be unwarranted. We recommend that analytical approaches be modified to circumvent these problems and explore three potential solutions: (1) specimen-based rarefaction, (2) coverage-based rarefaction, and (3) weighting ecometric means by taxonomic abundances. Of these, only the latter is robust to variation in sampling effort. Because abundance data are not always available and are potentially unreliable, we outline alternative approaches that could be implemented to contend with sample bias.
... Repeated and rapid desiccation of Lake Victoria would have also affected the dispersal patterns of early modern humans and other fauna. Desiccation of Lake Victoria, would have removed a significant geographic barrier and enhanced dispersal potential as grasslands would have expanded simultaneously with the retreat of the lake ( Fig. 1B; Tryon et al., 2016). Removal or reduction of Lake Victoria as a biogeographic barrier to fauna would have enhanced the Nilotic corridor as an avenue for the dispersal of early modern humans within and out of Africa (Beverly et al., 2017;Tryon et al., 2016). ...
... Desiccation of Lake Victoria, would have removed a significant geographic barrier and enhanced dispersal potential as grasslands would have expanded simultaneously with the retreat of the lake ( Fig. 1B; Tryon et al., 2016). Removal or reduction of Lake Victoria as a biogeographic barrier to fauna would have enhanced the Nilotic corridor as an avenue for the dispersal of early modern humans within and out of Africa (Beverly et al., 2017;Tryon et al., 2016). ...
Article
The effects of precipitation changes on tropical East African ecosystems and human populations is poorly understood due to the complex interplay between global and regional processes and missing data from key regions and time periods. We generate a water-budget model for Lake Victoria, the largest tropical lake in the world, the source of the White Nile, and a region that supports some of the densest human populations in Africa, that assesses the impact of changing climate on lake levels and the rate of lake level change. Model results demonstrate that significant changes in the size and volume of Lake Victoria are possible in response to changes in temperature, precipitation, and orbital forcing. This modeling indicates that Lake Victoria can transition back and forth between modern lake levels and complete desiccation in centuries to a few millennia, which is rapid enough to allow for two previously observed desiccation events between 14-18 ka, during which time the lake drained and refilled twice. Combined observations from modeling and estimates of paleoprecipitation indicate that Lake Victoria was likely desiccated between 94-36 ka. This dry interval partially overlaps the megadrought (140-70 ka) identified in Lakes Malawi and Tanganyika further south, and the cooler, drier conditions identified in the Gulf of Aden between 75-50 ka. This prolonged desiccation was probably driven by eccentricity-enhanced precession and high-latitude forcing that affected the Congo Air Boundary convergence. Using future climate projections, our model also predicts that at current rates of temperature change and previous rates of lake level fall, Lake Victoria could have no outlet to the White Nile within 10 years, and Kenya could lose access to the lake in <400 years, which would significantly affect the economic resources supplied by Lake Victoria to the East African Community.
... They are located between Lakes Turkana and Victoria, which have, in the past, been useful in illustrating temporal climatic variability (e.g. Tryon et al., 2016;Owen et al., 2018). The high elevation of the Cherangani (up to 3000 m above sea level) also ensures the preservation of pollen and fungal spores (Coetzee, 1967;Tryon et al., 2016;Owen et al., 2018). ...
... Tryon et al., 2016;Owen et al., 2018). The high elevation of the Cherangani (up to 3000 m above sea level) also ensures the preservation of pollen and fungal spores (Coetzee, 1967;Tryon et al., 2016;Owen et al., 2018). ...
Article
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Fungi are highly sensitive to environmental and climatic changes. Palaeoecological reconstructions utilising tropical African fungal spores, however, are rare and patchy. Here, we show that fossil fungal spores preserved in core KAP‐01 from the Cherangani Hills in Kenya tracks critical environmental changes in the African tropics since the Last Glacial Maximum (LGM), largely synchronous with observations in the pollen record from the same site. Consistent with the pollen record, the presence of fungal taxa in the record, albeit meagre, during the LGM point to an intermittent wetter Cherangani that allowed for the presence of the observed taxa and the prevalence of cool, dry conditions during the last deglaciation. The elevated fungal spore activity during the Late Holocene is evidence for warm, moist environmental conditions and broadly consistent with the pollen record. These different fungal spore taxa, which can be employed to track distinct environmental conditions and processes, provide a dimension that can be overlooked if the reconstruction of the palaeoenvironment were to rely solely on pollen. Thus the fungal spore record enables us to affirm the interpretation of the prevalence of warm, moist conditions evident from such as the Holocene pollen record.
... the development of the East African Rift, including several phases of aridity (Bishop & Trendall, 1966;Johnson, Kelts, & Odada, 2000;Lehman, 2009;Tryon et al., 2016). Additionally, human activities have exerted multifactorial pressures on freshwater environments in the ecoregion over recent decades, through habitat degradation, pollution, exploitation, the introduction of invasive species, ecosystem modifications and climate change (Hecky, Mugidde, Ramlal, Talbot, & Kling, 2010;Johnson et al., 2000;Sayer, Máiz-Tomé, & Darwall, 2018;Verschuren et al., 2002). ...
... This diversity was potentially maintained in mountain-fed river systems along the western branch of the East African Rift (Johnson et al., 2000). The penultimate phase of megadrought in the Lake Victoria ecoregion transpired at the end of the last interglacial ~ 125 ka (Tryon et al., 2016), and whereas the extent of aridity during this period is more uncertain in comparison to the LGM (Johnson et al., 1996(Johnson et al., , 2000, it corresponds broadly to the onset of viviparid population decline estimated in our ABC simulations, suggesting at least a similar level of aridity to that at the LGM. ...
Article
Ecosystems of Lake Victoria and riparian communities have been strongly disrupted by the introduction of the invasive Nile perch and its fishing industry. Beyond this invasion and other recent anthropogenic stressors, the Lake Victoria ecoregion also underwent phases of pronounced aridity over the Late Pleistocene, lastly during the Last Glacial Maximum (LGM). The consequences of recent and historic environmental change have been canvassed for the adaptive radiation of haplochromine cichlids occupying the ecoregion, but their effect on freshwater invertebrate diversity remains largely unknown. Here we use 15 microsatellite loci and approximate Bayesian computation to test whether viviparid gastropods experienced a population bottleneck during the LGM, as did cichlids. Clustering analyses support three viviparid gene pools in the Lake Victoria ecoregion, gathering specimens from 1) Lake Albert and the White Nile, 2) the Victoria Nile and Lake Kyoga and 3) Lake Victoria and tributaries. The last group contains the highest genetic diversity, but all groups have a considerable number of private alleles and are inferred to predate the LGM. Examinations of demographic history reveal a 190‐ to 500‐fold population decline that started ~125‐150 ka ago, thus substantially before the LGM bottleneck documented in haplochromine cichlids. Population collapses in viviparids are an order of magnitude more severe than declines in cichlids and have not been halted by the re‐establishment of freshwater ecosystems since the LGM. Recent anthropogenic ecosystem deterioration is causing homogenization of previously diversified microhabitats, which may contribute to (local) extinction and enhanced gene flow among species within gene pools.
... Here we present data from stratigraphy, micromorphology (petrography), and bulk geochemistry from six Late Pleistocene sites from northeastern Lake Victoria in Kenya that were deposited between 94 and 36 ka Beverly et al., 2015b;Blegen et al., 2015). These sites sample an approximately 55 km-long north to south transect along the eastern margin of the modern lake: Rusinga Island (n = 2), Mfangano Island (n = 1), and Karungu (n = 4) (Figure 1; Tryon et al., 2014Tryon et al., , 2016Beverly et al., 2015a,b;Blegen et al., 2015;Faith et al., 2015;Garrett et al., 2015). These deposits are all part a sequence of late Pleistocene deposits around the northeastern margin of Lake Victoria and the stratigraphy is dominated by paleosols, freshwater tufa, fluvial deposits, and volcaniclastic deposits (tuffs) that can be geochemically correlated between outcrops (Tryon et al., 2010Van Plantinga, 2011;Beverly et al., 2015a,b;Blegen et al., 2015Blegen et al., , 2016Faith et al., 2015). ...
... These reconstructions of the upper and lower paleo-CZ using paleosol features, grain size, and bulk geochemical proxies for MAP also agree with vegetation reconstructions using pedogenic carbonates, soil organic matter, and tooth enamel from Rusinga and Mfangano Islands, which indicate the local occurrence of a woodland to grassy woodland surrounded by an expansive C 4 grassland Garrett et al., 2015;Tryon et al., 2016). The fossils from this region are dominated by a diverse population of grazing herbivores and arid-adapted ungulates such as oryx (Oryx beisa) and Grevy's zebra (Equus grevyi), which are found far outside their modern range of arid eastern and northeastern Africa . ...
Article
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The impact of changing environments on the evolution and dispersal of Homo sapiens is highly debated, but few data are available from equatorial Africa. Lake Victoria is the largest freshwater lake in the tropics and is currently a biogeographic barrier between the eastern and western branches of the East African Rift. The lake has previously desiccated at ~17 ka and again at ~15 ka, but little is known from this region prior to the Last Glacial Maximum. The Pleistocene terrestrial deposits on the northeast coast of Lake Victoria (94–36 ka) are ideal for paleoenvironmental reconstructions where volcaniclastic deposits (tuffs), fluvial deposits, tufa, and paleosols are exposed, which can be used to reconstruct Critical Zones (CZ) of the past (paleo-CZs). The paleo-CZ is a holistic concept that reconstructs the entire landscape using geologic records of the atmosphere, hydrosphere, lithosphere, biosphere, and pedosphere (the focus of this study). New paleosol-based mean annual precipitation (MAP) proxies from Karungu, Rusinga Island, and Mfangano Island indicate an average MAP of 750 ± 108 mm year−1 (CALMAG), 800 ± 182 mm year−1 (CIA-K), and 1,010 ± 228 mm year−1 (PPM1.0) with no statistical difference throughout the 11 m thick sequence. This corresponds to between 54 and 72% of modern precipitation. Tephras bracketing these paleosols have been correlated across seven sites, and sample a regional paleo-CZ across a ~55 km transect along the eastern shoreline of the modern lake. Given the sensitivity of Lake Victoria to precipitation, it is likely that the lake was significantly smaller than modern between 94 and 36 ka. This would have removed a major barrier for the movement of fauna (including early modern humans) and provided a dispersal corridor across the equator and between the rifts. It is also consistent with the associated fossil faunal assemblage indicative of semi-arid grasslands. During the Late Pleistocene, the combined geologic and paleontological evidence suggests a seasonally dry, open grassland environment for the Lake Victoria region that is significantly drier than today, which may have facilitated human and faunal dispersals across equatorial East Africa.
... There is also evidence that Late Pleistocene humans were exploiting aquatic resources, potentially systematically, along the north African coast and rivers of Central Africa (Marean, 2016) ( Figure 2B). They likely inhabited productive lake margins, such as shoreline sites along Lake Victoria rich in shellfish and aquatic and semi-aquatic plants (Tryon et al., 2016). Archaeological evidence indicates that coastal foraging, both of shellfish and marine fish, continued even during the Last Glacial Maximum (Fisher et al., 2020; see also Keller et al., 2019). ...
... The archaeological record in Late Pleistocene Africa lacks the conclusive finds of Upper Paleolithic Europe, yet there is still evidence of low-mobility population exploiting the kinds of resources that support large groups and inequality. Findings from Late Pleistocene Equatorial Africa, such as 60-70 ka deposits near Lake Edward in the Democratic Republic of the Congo, indicate that populations exploiting dense, predictable aquatic resources lived in communities with low residential mobility (reviewed in Tryon et al. 2016). Research in the Upper Egyptian Nile Valley shows a large population until about 75 ka (Vermeersch & Van Neer, 2015). ...
Article
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Many researchers assume that until 10-12,000 years ago, humans lived in small, mobile, relatively egalitarian bands. This "nomadic-egalitarian model" suffuses the social sciences. It informs evolutionary explanations of behavior and our understanding of how contemporary societies differ from those of our evolutionary past. Here, we synthesize research challenging this model and articulate an alternative, the diverse Pleistocene model, to replace it. We review the limitations of using recent foragers as models of Late Pleistocene societies and the considerable social variation among foragers commonly considered small-scale, mobile, and egalitarian. We review ethnographic and archaeological findings covering 34 world regions showing that non-agricultural peoples often live in groups that are more sedentary, unequal, large, politically stratified, and capable of large-scale cooperation and resource management than is normally assumed. These characteristics are not restricted to extant Holocene hunter-gatherers but, as suggested by archaeological findings from 27 Middle Stone Age sites, likely characterized societies throughout the Late Pleistocene (until c. 130 ka), if not earlier. These findings have implications for how we understand human psychological adaptations and the broad trajectory of human history.
... Archaeologists have discovered shell middens, indicating a commitment to dense and predictable coastal resources, by at least c. 130 ka along the southern African coast 126 (Figure 2). There is also evidence that Late Pleistocene humans were systematically exploiting aquatic resources along the north African coast and rivers of Central Africa 127 ( Figure 2B), and they likely inhabited productive lake margins, such as shoreline sites along Lake Victoria rich in shellfish and aquatic and semi-aquatic plants 128 . In fact, some scholars now see aquatic (and particularly coastal) adaptation as central for the origin, evolution, and dispersal of modern humans 123,127,129 . ...
... The archaeological record in Late Pleistocene Africa lacks the conclusive finds of Upper Paleolithic Europe, yet there is still evidence for low-mobility population exploiting the kinds of resources that support large groups, hierarchy, and political complexity. Findings from Late Pleistocene Equatorial Africa, such as 60-70 ka deposits near Lake Edward in the Democratic Republic of the Congo, indicate that populations exploiting dense, predictable aquatic resources lived in communities with low residential mobility (e.g., multi-seasonal occupation with patchily dense artifact accumulations) (reviewed in ref. 128 ). ...
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Many researchers assume that until 10-12,000 years ago, humans lived in small, mobile, relatively egalitarian bands composed mostly of kin. This “nomadic-egalitarian model” informs evolutionary explanations of behavior and our understanding of how contemporary societies differ from those of our evolutionary past. Here, we synthesize research challenging this model and propose an alternative, the diverse histories model, to replace it. We outline the limitations of using recent foragers as models of Late Pleistocene societies and the considerable social variation among foragers commonly considered small-scale, mobile, and egalitarian. We review ethnographic and archaeological findings covering 34 world regions showing that non-agricultural peoples often live in groups that are more sedentary, unequal, large, politically stratified, and capable of large-scale cooperation and resource management than is normally assumed. These characteristics are not restricted to extant Holocene hunter-gatherers but, as suggested by archaeological findings from 27 Middle Stone Age sites, likely characterized societies throughout the Late Pleistocene (until c. 130 ka), if not earlier. These findings have implications for how we understand human psychological adaptations and the broad trajectory of human history.
... This is one of the most negative δ 13 C values for any fossil tooth enamel from Africa; other herbivores with such negative values are found in cave deposits in Southeastern Asia and are interpreted as being associated with closed canopy conditions (Bocherens et al. 2017;Ma et al. 2017Ma et al. , 2019Bacon et al. 2018). Thus, this particular sample presents an interesting puzzle for interpretation since there is no other clear evidence for closed-canopy conditions in the associated fauna or isotopes, and most lines of evidence point to relatively dry conditions and an expansion of C 4 grasslands across the Lake Victoria basin during the Late Pleistocene (e.g., Tryon et al. 2010Tryon et al. , 2012Tryon et al. , 2016Faith et al. 2015Faith et al. , 2020Garrett et al. 2015;Beverly et al. 2017). The Rusinga Hylochoerus may derive from sediments reflecting a humid phase that is otherwise not represented by the faunas, but analysis of paleosols from Rusinga and nearby Karungu indicate that relatively dry conditions persisted from ~94-36 ka (Beverly et al. 2017). ...
... The Rusinga Hylochoerus may derive from sediments reflecting a humid phase that is otherwise not represented by the faunas, but analysis of paleosols from Rusinga and nearby Karungu indicate that relatively dry conditions persisted from ~94-36 ka (Beverly et al. 2017). The complete absence of Later Stone Age artefacts (dating from < 36 ka in the region; Tryon et al. 2016;Blegen et al. 2017) at Nyamsingula also suggests that it is unlikely the specimen derives from undocumented or eroded Holocene deposits that sample a more humid climate with closed habitats. ...
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African forest hogs (genus Hylochoerus) are extant Afro-tropical suids that inhabit a variety of forest environments and thick bushlands and are predominantly herbivores. Hylochoerus likely evolved from a Pleistocene Kolpochoerus majus-like ancestor, but its recent evolutionary history is virtually unknown. Here, we describe a partial right lower third molar from the Late Pleistocene Wasiriya Beds of Rusinga Island (~50-36 ka). The crowns are mesiodistally compressed in a bunolophodont fashion and arranged in columnar pillars that resemble those of extant Hylochoerus. We provide accurate data derived from computed tomography on the hypsodonty index (HI) of extant Hylochoerus and show that the Rusinga third molar crown was as tall as those of its modern counterpart (HI = 1.8-2.0). Stable carbon isotope analyses suggest that the diet of the Rusinga specimen (δ 13 C = −17.0 ‰) was also like that of extant forest hogs (δ 13 C average = −17.6 ‰). This extremely negative value contrasts strikingly with those of other fossil large herbivores at Rusinga (δ 13 C average = −0.7 ‰.). Among the potential explanations for this anomaly, the most likely is that the Late Pleistocene paleoenvironments were more heterogeneous than previously considered and may have included closed-canopy woodland in the highlands of Rusinga.
... Fish fossils at sites at Aduma in the middle and later part of MIS 5 (~100-80 ka; Yellen et al. 2005) and perhaps along the Blue Nile (Kappelman et al. 2014) suggest predation of fish along inland river systems during the same time. Evidence for intensive use of aquatic resources around the major lakes is lacking, although the geological record may be partially responsible for this lacuna (e.g., Tryon et al. 2016). ...
... External environmental causation has a long tradition in archaeological explanation and there is considerable evidence that people during the Paleolithic successfully adapted to climatic and ecological changes. Recent research, however, showed that environmental change must be considered in concert with demographic and sociocultural factors, particularly at finer scales of analyses ; see also Villa et al. 2012;Clark 2013;Porraz et al. 2013;Tryon and Faith 2016). There is also a need to better demonstrate causal links between particular environmental changes and patterns in the archaeological record other than mere correlation (see Chase 2010;Blome et al. 2012;d'Errico and Banks 2013;Marean et al. 2015). ...
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The period from 200,000 to 30,000 years ago in Africa encompasses the archaeological background for the early evolution and global dispersal of Homo sapiens. Here we provide an overview of current models of behavioral change and cultural evolution in this timeframe, followed by a review on the timing and temporal tra-jectory of relevant empirical data in Africa. Because recent anthropological and genetic work has highlighted the importance of structure within ancient populations of Africa, we adopt a geographically explicit perspective. We emphasize comparisons between the archaeological records of southern, northern, eastern, central and western Africa, recognizing the varying geological and environmental backgrounds, political circumstances, and histories of research across the continent. Our review finds different records and temporal trajectories for complex material culture and behavioral innovations among the African regions, with the earliest evidence for many cultural changes already present during the late Middle Pleistocene in all areas. The bulk of the evidence, however, comes from Marine Isotope Stages (MIS) 5-3, a period characterized by complex temporal trajectories and spatial differences among and within regions. Prominent models for a late emergence of sophisticated behaviors at ~50,000 years ago or a gradual and cumulative evolution of cultural complexity in all of Africa are not supported. In light of these results, we advocate abandoning continent-wide, directional and unilinear models of cultural change in favor of more highly contextualized, temporally variable, and historically contingent trajectories in different regions, encapsulated in the concept of complex landscapes of cultural evolution.
... most common ecotone occurring between temperate conifer forest and tropical xerophytic shrubland, distributed widely across the region though most concentrated towards the eastern edge of Lake Victoria and the associated region. Today, Lake Victoria sits on the junction between central African rainforests and savanna habitats to the east, forming an important boundary for large mammal 40 and human 41 populations. Our phased models (Fig. 5) propose that the region to the east of Lake Victoria, including the Eastern African Rift Valley, would have seen sustained and persistent occupation throughout the Middle to Late Pleistocene in the face of climatic fluctuation, implicating it as a potential refugium for hominins in eastern Africa. ...
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Eastern Africa has played a prominent role in debates about human evolution and dispersal due to the presence of rich archaeological, palaeoanthropological and palaeoenvironmental records. However, substantial disconnects occur between the spatial and temporal resolutions of these data that complicate their integration. Here, we apply high-resolution climatic simulations of two key parameters, mean annual temperature and precipitation, and a biome model, to produce a highly refined characterisation of the environments inhabited during the eastern African Middle Stone Age. Occupations are typically found in sub-humid climates and landscapes dominated by or including tropical xerophytic shrubland. Marked expansions from these core landscapes include movement into hotter, low-altitude landscapes in Marine Isotope Stage 5 and cooler, high-altitude landscapes in Marine Isotope Stage 3, with the recurrent inhabitation of ecotones between open and forested habitats. Through our use of high-resolution climate models, we demonstrate a significant independent relationship between past precipitation and patterns of Middle Stone Age stone tool production modes overlooked by previous studies. Engagement with these models not only enables spatiotemporally explicit examination of climatic variability across Middle Stone Age occupations in eastern Africa but enables clearer characterisation of the habitats early human populations were adapted to, and how they changed through time.
... Three trenches were opened in 2011, totaling 19 m 2 . consistent with a widespread semi-arid grassland environment (Faith et al., 2011Tryon et al., 2012Tryon et al., , 2016Garrett et al., 2015). However, multiple stream and spring deposits, as well as the presence of wetland fauna such as hippopotamuses and reduncin bovids at the Nyamita locality, indicate that free-standing water was likely available year-round on Rusinga Island (Tryon et al., 2010Beverly et al., 2015a, b). ...
Article
The foraging behaviors of Middle Stone Age (MSA) early modern humans have largely been based on evidence from well-stratified cave sites in South Africa. Whereas these sites have provided an abundance of data for behavioral reconstruction that are unmatched elsewhere in Africa, they are unlikely to preserve evidence of the diversity of foraging strategies employed by MSA hunters who lived in a variety of ecological and landscape settings across the African continent. Here we describe the results of recent excavations at the open-air site of Bovid Hill at Wakondo, Rusinga Island, Kenya, which yielded 24 in situ MSA artifacts within an assemblage of bones comprised exclusively of the extinct alcelaphin bovid Rusingoryx atopocranion. The excavated faunal assemblage is characterized by a prime-age-dominated mortality profile and includes cut-marked specimens and an associated MSA Levallois blade-based artifact industry recovered from a channel deposit dated to 68 ± 5 ka by optically stimulated lumines-cence. Taphonomic, geologic, and faunal evidence points to mass exploitation of Rusingoryx by humans at Bovid Hill, which likely represents an initial processing site that was altered post-depositionally by fluvial processes. This site highlights the importance of rivers and streams for mass procurement in an open and seasonal landscape, and provides important new insights into MSA behavioral variability with respect to environmental conditions, site function, and tactical foraging strategies in eastern Africa. Bovid Hill thus joins a growing number of MSA and Middle Paleolithic localities that are suggestive of tactical hunting behaviors and mass capture of gregarious ungulate prey.
... During the final stages of the Pleistocene, many African great lakes experienced significant water-level drops with related impacts on vegetation cover (Gasse 2000;Barker and Gasse 2003;Gasse et al. 2008;Vincens et al. 2005). Lake Victoria evaporated completely between c. 17,000-16,000 BP and again c. 15,000-14,000 BP, with a demonstrable Bpush-pull^effect on human and animal populations (Johnson et al. 1996;Tryon et al. 2015;Verheyen et al. 2003). Although we lack fine-grained palaeoclimatic data for many subregions (Grine 2016), the absence of archaeological sites in many parts of the continent during glacial maxima suggests that many regions could not sustain human life (Willoughby 2012). ...
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The Mlambalasi rockshelter in the Iringa Region of southern Tanzania has rich artifactual deposits spanning the Later Stone Age (LSA), Iron Age, and historic periods. Middle Stone Age (MSA) artifacts are also present on the slope in front of the rockshelter. Extensive, systematic excavations in 2006 and 2010 by members of the Iringa Region Archaeological Project (IRAP) illustrate a complex picture of repeated occupations and reuse of the rockshelter during an important time in human history. Direct dates on Achatina shell and ostrich eggshell (OES) beads suggest that the earliest occupation levels excavated at Mlambalasi, which are associated with human burials, are terminal Pleistocene in age. This is exceptional given the rarity of archaeological sites, particularly those with human remains and other preserved organic material, from subtropical Africa between 200,000 and 10,000 years before present. This paper reports on the excavations to date and analysis of artifactual finds from the site. The emerging picture is one of varied, ephemeral use over millennia as diverse human groups were repeatedly attracted to this fixed feature on the landscape. © The Author(s) 2017.
... According to literature [15], when English schooling at college goes global, it will be localized, and localization of English schooling at college is an unavoidable result of globalization. According to literature [16] literature, the number of college students in China has risen sharply as a result of the continuous expansion of university enrollment, but English teachers are becoming increasingly tense, which has led to the continuous expansion of class size, with some colleges and universities having more than 100 students in a class. ...
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The importance of learning English is increasing as China’s foreign exchanges become more frequent. China’s independent colleges have been steadily growing in recent years, with the main school’s main characteristic of cultivating applied talents, and teaching quality gradually improving. College English teaching is a practical application of college English education and instruction. The “sum of beliefs, recognized values, and technologies commonly accepted by the members of a specific community” is the world outlook and mode of behavior that a group of researchers engaged in a particular science adopts. Modern information technology has pervaded people’s work and lives since the dawn of the information age, and it is now widely used in a variety of fields. Teachers’ primary roles have shifted from disseminator of information, presenter of knowledge, transmitter of culture, and provider of correct answers in today’s learning environment supported by modern information technology to promoter of learning, organizer of activities, student helper, and interactive collaborator. This paper obtains some information useful to the development of teaching work based on the data mining algorithm used in the mining practice of the educational administration information management system. This information is useful for improving teaching quality, implementing the talent development program more effectively, mastering student skill development, and teachers’ teaching situations.
... Given their habitat and dietary differences [55,56], taxonomic identifications of bovids beyond the family level are crucial for inferring past environments [57][58][59][60][61][62][63]. Species-level identifications are most effective, allowing for detailed morphological studies that can further clarify environmental context [64,65], but broad identifications to tribe or subfamily can still provide useful information, particularly in poorly preserved or small assemblages in which few specimens are morphologically identifiable to genus or species. ...
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Assessing past foodways, subsistence strategies, and environments depends on the accurate identification of animals in the archaeological record. The high rates of fragmentation and often poor preservation of animal bones at many archaeological sites across sub-Saharan Africa have rendered archaeofaunal specimens unidentifiable beyond broad categories, such as “large mammal” or “medium bovid”. Identification of archaeofaunal specimens through Zooarchaeology by Mass Spectrometry (ZooMS), or peptide mass fingerprinting of bone collagen, offers an avenue for identification of morphologically ambiguous or unidentifiable bone fragments from such assemblages. However, application of ZooMS analysis has been hindered by a lack of complete reference peptide markers for African taxa, particularly bovids. Here we present the complete set of confirmed ZooMS peptide markers for members of all African bovid tribes. We also identify two novel peptide markers that can be used to further distinguish between bovid groups. We demonstrate that nearly all African bovid subfamilies are distinguishable using ZooMS methods, and some differences exist between tribes or sub-tribes, as is the case for Bovina (cattle) vs. Bubalina (African buffalo) within the subfamily Bovinae. We use ZooMS analysis to identify specimens from extremely fragmented faunal assemblages from six Late Holocene archaeological sites in Zambia. ZooMS-based identifications reveal greater taxonomic richness than analyses based solely on morphology, and these new identifications illuminate Iron Age subsistence economies c. 2200–500 cal BP. While the Iron Age in Zambia is associated with the transition from hunting and foraging to the development of farming and herding, our results demonstrate the continued reliance on wild bovids among Iron Age communities in central and southwestern Zambia Iron Age and herding focused primarily on cattle. We also outline further potential applications of ZooMS in African archaeology.
... Furthermore a clear fireclimate relationship may also be obscured by ancient and/or more recent human activity in the region, the intensity of which must have varied depending on demographic and lifestyle changes (e.g. Hohn and Neumann, 2012;Barboni, 2014;Tryon et al., 2016). To control for the latter, we also test to what extent long-term fire dynamics affected the area's vegetation, by using direct gradient analysis, and by quantifying the relative variance explained by charcoal (fire) over pollen assemblages (vegetation). ...
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In tropical ecosystems, climate and human impact are generally considered the main determinants of savanna fire distribution, but their relative roles in controlling fire dynamics over the long-term are difficult to assess, due to scarcity of multi-proxy, long-term data. We combined pollen, charcoal and sedimentological data obtained from the 1200-year sediment record of Lake Simbi, a small crater lake near Lake Victoria in western Kenya, to assess the main drivers of century-scale variability in biomass burning, and its long-term effects on local vegetation dynamics. The effect of climate variability was inferred through comparison of the Simbi charcoal time series with an independent reconstruction of the region's moisture-balance history, from the sediment record of nearby Lake Victoria. Our data show that decade-scale climate variability exerted a primary control over burning, with intermediate levels of moisture maximizing the occurrence of fire, in accordance with both spatial and temporal patterns of biomass burning at regional to sub-continental scales. Despite the challenge to identify pre-colonial human impact unambiguously, our data also suggest that human disturbances between 1000 and 1200 AD likely amplified the effect of climate on biomass burning, in contrast to today's situation, where fire prevalence is mostly suppressed due to agricultural landscape fragmentation. Finally, combination of the pollen and charcoal data allowed to quantitatively estimate the effect of fire on vegetation, with fire explaining up to one third of the reconstructed vegetation changes through time. This variability is mostly related to the expansion/contraction of savanna ecosystems, showing that before the 20th century (i.e., the colonial and post-independence periods), fire mediated this region's vegetation changes at century and millennial time scales. Our results produce a long-term historical perspective on the variability of biomass burning in tropical savanna ecosystems, with relevance for assessing future trends resulting from ongoing climate and land-use changes.
... Buticha [8][9][10], and in the Lake Victoria Basin [11]. The transition is often characterised archaeologically by decreases in prepared-core technologies and the production of retouched points and by concomitant increases in (backed) microliths, prismatic blade(lets) and bipolar reduction methods [12]. ...
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The Middle to Later Stone Age transition marks a major change in how Late Pleistocene African populations produced and used stone tool kits, but is manifest in various ways, places and times across the continent. Alongside changing patterns of raw material use and decreasing artefact sizes, changes in artefact types are commonly employed to differentiate Middle Stone Age (MSA) and Later Stone Age (LSA) assemblages. The current paper employs a quantitative analytical framework based upon the use of neural networks to examine changing constellations of technologies between MSA and LSA assemblages from eastern Africa. Network ensembles were trained to differentiate LSA assemblages from Marine Isotope Stage 3&4 MSA and Marine Isotope Stage 5 MSA assemblages based upon the presence or absence of 16 technologies. Simulations were used to extract significant indicator and contra-indicator technologies for each assemblage class. The trained network ensembles classified over 94% of assemblages correctly, and identified 7 key technologies that significantly distinguish between assemblage classes. These results clarify both temporal changes within the MSA and differences between MSA and LSA assemblages in eastern Africa.
... Our results also con rm the importance of wooded ecotones for sustaining MSA populations [9], with the most common ecotone occurring between temperate conifer forest and tropical xerophytic shrubland, distributed widely across the region though most concentrated towards the eastern edge of Lake Victoria and the associated region, where most assemblages occupy ecotones between tropical xerophytic shrubland and various forested/woodland biomes. Today, Lake Victoria sits on the junction between central African rainforests and savanna habitats to the east, forming an important boundary for large mammal [30] and human [31] populations. Our phased models (Fig. 5) propose that the region to the east of Lake Victoria would have seen sustained and persistent occupation throughout the Middle to Late Pleistocene in the face of climatic uctuation, implicating it as a potential refugium for hominins in eastern Africa. ...
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Eastern Africa has played a prominent role in debates about human evolution and dispersal due to the presence of rich archaeological, palaeoanthropological and palaeoenvironmental records. However, substantial disconnects occur between the spatial and temporal resolutions of these data that complicate their integration. Here, we apply high-resolution climatic simulations of two key parameters, mean annual temperature and precipitation, and a biome model, to produce a highly refined characterisation of the environments inhabited during the eastern African Middle Stone Age. Occupations are typically found in sub-humid climates and landscapes dominated by or including tropical xerophytic shrubland. Marked expansions from these core landscapes include movement into hotter, low-altitude landscapes in Marine Isotope Stage 5 and cooler, high-altitude landscapes in Marine Isotope Stage 3, with the recurrent inhabitation of ecotones between open and forested habitats. Through our use of high-resolution climate models, we demonstrate a significant independent relationship between past precipitation and patterns of Middle Stone Age stone tool use overlooked by previous studies. Engagement with these models not only enables spatiotemporally explicit examination of climatic variability across Middle Stone Age assemblages in eastern Africa but enables clearer characterisation of the habitats early human populations were adapted to, and how they changed through time.
... However, the chronologies and environmental contexts of these key behavioral transitions are not clear. Sites >50,000 years old have only just begun to be identified beyond the East Africa Rift System 23 and are limited to the Lake Victoria region [24][25][26] . ...
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The Middle to Later Stone Age transition in Africa has been debated as a significant shift in human technological, cultural, and cognitive evolution. However, the majority of research on this transition is currently focused on southern Africa due to a lack of long-term, stratified sites across much of the African continent. Here, we report a 78,000-year-long archeological record from Panga ya Saidi, a cave in the humid coastal forest of Kenya. Following a shift in toolkits ~67,000 years ago, novel symbolic and technological behaviors assemble in a non-unilinear manner. Against a backdrop of a persistent tropical forest-grassland ecotone, localized innovations better characterize the Late Pleistocene of this part of East Africa than alternative emphases on dramatic revolutions or migrations.
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To better understand the potential role of environmental change in mediating human dispersals across equatorial East Africa, this study examines the biogeographic histories of ungulates, including a summary of current knowledge and fossil evidence stemming from our fieldwork in the Kenyan portion of the Lake Victoria basin. Phylogeographic and paleontological evidence indicates that vegetation changes across Quaternary climate cycles mediated ungulate distributions and dispersals via the opening and closing of biogeographic barriers in equatorial East Africa. Dispersal capabilities would have been enhanced during phases of grassland expansion and diminished during phases of grassland contraction. We propose that the distribution and dispersal of diagnostic technological markers in the archaeological record may be similarly influenced by environmental changes. The Middle Stone Age record from the Lake Victoria region provides intriguing examples of possible environmentally mediated technological dispersals.
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A 50 m thick stratigraphic section at Ngira, near Karungu on the shore of Lake Victoria in western Kenya, documents the early Miocene paleoenvironments of the area. The basal Ngira paleosol is a 7.6 m thick, oxisolic Vertisol that formed during a prolonged period of pedogenesis; it began as a smectite-dominated Vertisol that was later overprinted through polypedogenesis to become a kaolinitic paleosol highly depleted of all base cations, with abundant Fe concentrations and depletions, and complexly variegated color mottle patterns that reflect extensive ferruginization. Paleoenvironmental reconstructions using bulk geochemistry indicate warm and wet conditions during development of the Ngira paleosol that probably supported a tropical seasonal forest on a stable upland surface for 10s to 100s of thousands of years. Following this long-lived stable landscape, rapid subsidence, perhaps associated with slip on a high-angle fault associated with the onset or progression of the Nyanza Rift and/or the development and eruptive history of the nearby Kisingiri volcano, buried the paleosol and formed a nascent lake basin that experienced multiple transgressions and regressions. During one interval of regression, fluvial sandstones and conglomerates were deposited along with fluvio-lacustrine sandstones and claystones that include weakly developed paleosols. These weakly-developed paleosols indicate a relatively dry paleoenvironment with seasonal precipitation, and probably a shrubland/bushland or riparian forest habitat. Important terrestrial and aquatic vertebrate fossils are primarily preserved within fluvial and fluvio-lacustrine deposits, indicating that the terrestrial Karungu fauna lived in a relatively dry and open habitat. This study demonstrates polypedogenesis and inferences regarding onset of abrupt tectonic activity in the early Miocene in equatorial eastern Africa, and emphasizes the contrasts between landscape stability of the Ngira paleosol and the poorly developed soils in the fluvio-lacustrine facies.
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Here we report tephra correlations, lithic artifacts, obsidian sourcing data, and fauna from nine Late Pleistocene localities of the eastern Lake Victoria basin of western Kenya, as well as new excavations from the 49-36 ka site of Nyamita Main on Rusinga Island. The Late Pleistocene of Africa is an important period for the evolution and dispersals of Homo sapiens. A conspicuous behavioral feature of this period is the replacement of Middle Stone Age (MSA) technologies by Later Stone Age (LSA) technologies. Current research shows this process is complex with the LSA appearing and the MSA disappearing at different times in different places across Africa. Accounting for this pattern requires a precise chronology, detailed evidence of past human behavior and environmental reconstructions of the appropriate scale. Data presented here provide this detail. Tephra correlations improve the regional chronology and expand the lateral area of Late Pleistocene eastern Lake Victoria basin exposures from ~650km 2 to >2500km 2. Lithic artifacts show MSA technology is present younger than 36 ka in western Kenya, 25-35 kyr younger than the first appearance of early LSA technology elsewhere in equatorial East Africa. Obsid-ian sourcing data presented here shows the use of the same raw material sources by MSA and LSA populations through long periods of time from >100 ka through <36 ka. The methods employed here provide the temporal resolution and appropriate geographic scale to address modern human behavioral evolution.
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The sediment record from Lake Victoria is an important archive of regional environmental and climatic conditions, reaching back more than 15,000 cal. years before present (15 ka BP). As the largest lake by area in East Africa, its evolution is key to understanding regional palaeohydrological change during the late Pleistocene and Holocene, including controls on the Nile River flow. As well as important palaeoenvironmental proxies, the lake contains a unique record of explosive volcanism from the central Kenyan Rift, in the form of fine-grained volcanic ash (tephra) layers, interpreted as airfall deposits. In the V95-1P core, collected from the central northern basin of the lake, tephra layers vary in concentration from 10s to 10s of 1000s of glass shards per gram of sediment. None of the tephra are visible to the naked eye, and have only been revealed through careful laboratory processing. Compositional analyses of tephra glass shards has allowed the tephra layers to be correlated to previously unrecognized eruptions of Eburru volcano around 1.2 and 3.8 ka, and Olkaria volcano, prior to 15 ka. These volcanoes lie ~300 km east of the core site in the Kenyan Rift. Our results highlight the potential for developing cryptotephra analysis as a key tool in East African palaeolimnological research. Tephra layers offer opportunities for precise correlation of palaeoenvironmental sequences, as well as windows into the eruption frequency of regional volcanoes and the dispersal of volcanic ash.
Article
The later Middle through early Late Pleistocene (~100–400 ka) of East Africa is an important time and place for the evolution of our species. This period records the first appearance of Homo sapiens and spans significant technological changes including the decline of large handheld stone tools characteristic of the Acheulean, the development of stone tool technologies collectively known as the Middle Stone Age (MSA). These include diverse Levallois prepared core techniques and the manufacture and use of pointed weapons. It is in association with MSA technologies in sub-Saharan Africa that most of the behaviors characteristic of modern humans first appear. This doctoral dissertation provides new chronological and archaeological data relevant to hominin behavior associated with MSA technology in the Middle and Late Pleistocene of East Africa. Improved chronological resolution is achieved through tephrostratigraphy, the correlation of volcanic ashes, combined with chronometric dating in two regions: the Kapthurin Formation in the Rift Valley, Baringo, Kenya and the eastern Lake Victoria Basin of western Kenya. New data on hominin behavior is provided by archaeological excavations of two sites: 1) The 196-226 ka Sibilo School Road Site in the Kapthurin Formation. 2) The 33–49 ka site of Nyamita Main in the eastern Lake Victoria Basin. The archaeology of the Kapthurin Formation and the eastern Lake Victoria Basin are connected thematically by the presence of MSA technology. These basins are also connected stratigraphically and chronologically, as this study shows, by tephra correlations between them. Results of this work demonstrate: 1) Levallois prepared core techniques, important aspects of MSA technology, are shown to be >380 ka in the Kapthurin Formation, ~100 kyr older than previously estimated in East Africa. 2) Long distance transport (>166 km) of high quality obsidian for stone tool manufacture was a feature of hominin behavior associated with Middle Pleistocene MSA technology ~200 ka ago. 3) MSA technology persisted in East Africa later than 49 ka and perhaps later than 33 ka, after Later Stone Age technologies, often considered categorically superior, are documented in the region. By demonstrating both the early and late presence of various aspects of MSA technology and associated hominin behavior this work shows that tephrostratigraphy and the excavation of new archaeological material in East Africa are productive means of producing new and important data on the MSA and the evolution of human behavior.
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It has long been proposed that pre-modern hominin impacts drove extinctions and shaped the evolutionary history of Africa’s exceptionally diverse large mammal communities, but this hypothesis has yet to be rigorously tested. We analyzed eastern African herbivore communities spanning the past 7 million years—encompassing the entirety of hominin evolutionary history—to test the hypothesis that top-down impacts of tool-bearing, meat-eating hominins contributed to the demise of megaherbivores prior to the emergence of Homo sapiens . We document a steady, long-term decline of megaherbivores beginning ~4.6 million years ago, long before the appearance of hominin species capable of exerting top-down control of large mammal communities and predating evidence for hominin interactions with megaherbivore prey. Expansion of C 4 grasslands can account for the loss of megaherbivore diversity.
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Cambridge Core - Geomorphology and Physical Geography - The Nile Basin - by Martin Williams
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The archaeological record of Late Pleistocene Africa is characterized by behavioral diversity and change, notably the technological shift from the Middle Stone Age (MSA) to Later Stone Age (LSA). Recent research shows the MSA-LSA transition was a spatially and temporally complex process. Understanding this transition requires a composite record of archaeological sites from precise chronological and stratigraphic contexts within multiple regions. Here we present excavation and analysis of two open-air Late Pleistocene sites in chronological and geographic association: Anderea’s Farm 1 (GrJe-8) and Kapsarok 1 (GrJe-9), from the Nyanza Rift, Kenya. Volcanic ash correlations of artifact-bearing sediments provide ages of ∼ 45–36 ka for Anderea’s Farm 1 (GrJe-8) and ∼ 50 ka for Kapsarok 1 (GrJe-9). Locally procured lavas were used to produce different stone tools by disparate technological methods. Lithic production at Anderea’s Farm 1 focused on the manufacture of short irregular flakes using expedient and discoidal methods, and tools are dominated by heavy-duty types. In contrast, Kapsarok 1 is characterized by elongated and convergent blanks produced using hierarchical core technologies. Viewed together, Kapsarok 1 and Anderea’s Farm 1 emphasizes high diversity in Late Pleistocene technology of the Victoria Basin. We argue these different technologies are most parsimoniously interpreted as expressions of a broad and flexible behavioral repertoire. Further, our results emphasize how excavation and analysis of open-air archaeological sites in secure chronological and stratigraphic contexts provides the means to sample the necessary range of human behaviours across a landscape commensurate with past forager geographic ranges.
Article
Site-specific habitat reconstructions in the form of faunal enamel stable carbon and oxygen isotope data allow for a finer assessment of the context of Homo sapiens in eastern Africa. To date, these studies have focused on a small collection of sites within a constrained spatiotemporal scope. Here, I analyse a compilation of faunal stable isotopes from the Kibish Formation and Porc Epic Cave, Ethiopia, and Rusinga and Mfangano Islands, Karungu, Lukenya Hill, and Panga ya Saidi, Kenya. New data for primate and notably Homo sapiens at Porc Epic are presented. Faunal isotope data indicate that the Lake Victoria and northern Lake Turkana basins were dominated by open grasslands between ~ 105 ka and 50 ka. Sites near the Ethiopian Rift and closer to the coast were at least in part buffered from the environmental changes that occurred further inland. In the following period, ~ 49 ka – 20 ka, inland sites see more wooded conditions while Panga ya Saidi at the coast becomes drier. This compilation provides evidence for spatial and temporal trends in local habitats necessary for understanding the mechanisms through which human populations exchanged genes, ideas, and behaviours during the Late Pleistocene.
Article
The ecological spatial landscape pattern of urban waters is not only a sign of the urbanization process but also a prerequisite for promoting the sustainable development of the city, in order to improve the ecological landscape construction of urban waters and promote the sustainable development of ecological cities, propose a study on the scale effect, and change characteristics of the ecological landscape pattern of urban waters. This study selected two areas composed of four ecological water landscapes in the City of Nanchang as research objects. The landscape elements are obtained through remote sensing technology, and vector machine classification is used to ensure the accuracy of the classification. Quantitative calculations of spatial patterns and characteristics are carried out on the basis of 5 category level indexes and 6 landscape level indexes, and spatial effect analysis is carried out using granularity setting and amplitude changes. For the magnitude effect of the test type level index, the landscapes C and D in zone 1 have peak values, which are 12km and 24km, respectively. The landscapes C and D of area 2 have peaks at 9km and 24km respectively, but the overall trend of change is relatively stable. The growth trend of landscape B in the two study areas is the most obvious, crossing landscape D and landscape A at 15km and 21km respectively. With the increase of particle size, the three types of indexes of NP, PD, and LSI of landscape B and C all show significant particle size effect, and the best particle size is 30m. With the increase in amplitude, the four indexes of PLAND, NP, PD, and LSI have strong amplitude effects. Landscape A gradually increases with the increase of the spatial scope, while the proportion of landscape B, C, and D gradually decreases, and the proportion of landscape D is the smallest. The above results confirm that the method in this paper has good results in the analysis of the scale effect and change characteristics of the urban water ecological landscape pattern, and it has certain reference value in the ecological construction of urban waters.
Article
Modern human evolution in Africa over the last ∼300 kyr is complex, with a variety of behavioral and biological changes appearing at different times and places. Explaining this pattern, as well as its relationship to paleoenvironmental circumstances, requires chronological and stratigraphic control of the paleoanthropological record. This study employs tephrostratigraphy, the chemical correlation of volcanic ashes (tephras), to provide chronostratigraphic context for modern human evolution in the Middle Pleistocene–Holocene of equatorial East Africa. This work geographically expands the eastern Lake Victoria Basin tephrostratigraphic framework over an area >16,000 km². Geochemical comparisons show that most eastern Lake Victoria Basin tephras are derived from the volcanoes of the Central Kenyan Rift. New tephra correlations in the eastern Lake Victoria Basin incorporate 11 terrestrial localities throughout the Nyanza Rift as well as the V95–1P sediment core from the Ugandan waters of Lake Victoria. The spatial expansion of the eastern Lake Victoria Basin tephrostratigraphy also extends the previously documented ∼94–36 ka chronology of the tephra sequence to encompass most of the last ∼240 kyr. Tephra correlations presented here provide new ages for previously excavated, but undated, archaeological sites including Songhor (GqJe-1) = >94 ka, Simbi (GrJe-2) = 45–36 ka, and Muguruk (GqJc-1) where the correlation of a ∼49–36 ka tuff may help constrain the age for some or all of the site’s multiple archaeological levels. The tephrostratigraphy presented here thus constitutes a necessary step in expanding a Middle Pleistocene–Holocene chronostratigraphic framework across equatorial East Africa, which is fundamental to future studies on modern human evolution and behavioral change through time.
Chapter
Data related to the human occupation density of the Lower Nile Valley are very much impacted by the extensive land reclamation, Nile erosion and sedimentation effects. After 40 ka BP population density became restricted. A very significant increase of population, fishers along intermittent lakes, is correlated with the dry phases of Greenland Stadial 2 (22.9-14.7 ka CalBP). During Greenland Interstadial 1 population density became very reduced and nearly no material remains are found from the following 4000 years. The available chronometric dated material remains of humans for the time period of 40 to 10 ka CalBP from four regions, the Maghreb, Libya, Egypt and the Southern Levant, are analysed by a CalPal approach. It appears that the occupation of those regions through time was diversified and probably related to climatic proxies. It appears that contacts with Sub-Saharan Africa were quite reduced, suggesting that culturally the humans from the Lower Nile Valley and the rest of Northern Africa have more in common with the Levantine and European Upper Palaeolithic than with the African Later Stone Age, confirming a “Back to Africa”.
Chapter
The archaeological data available in Africa for the period ranging from 75 to 12 ka are generally attributed to two major Palaeolithic phases: the Middle Stone Age (MSA) and the Later Stone Age (LSA). This timeframe corresponds to the last glacial period the Earth experienced, characterised by high climatic variability and a general trend towards more arid conditions (lower temperatures and precipitation) culminating in Marine Isotope Stage (MIS) 2, also referred as the Big Dry (ca. 29-15 ka) before a shift to more humid conditions (African Humid Period). In this paper, we review current archaeological evidence in the Horn of Africa between 75 and 12 ka. We first discuss this evidence in light of palaeoenvironmental data and in particular with regard to the potential impact of the Big Dry on human occupation in the region. We then discuss the place of the Horn of Africa in a wider macro-regional context and evaluate potential links with neighbouring regions.
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The Lithic Technologies of the Epipaleolithic Hunter-Gatherers in the Negev, Israel: Implications from Refitting Studies. In the course of intensive systematic surveys and excavations in the western Negev Desert, Israel, dozens of Upper Paleolithic (ca. 46-23 ka cal BP) and Epipaleolithic (23-11.5 ka cal BP) sites were investigated. Traditional lithic techno-typological studies enabled assignment of the assemblages to a series of distinct temporally and spatially well-defined socio-cultural entities. Field observations indicated the potential for systematic refitting of the lithic assemblages. An extensive refitting program was conducted incorporating 30 assemblages with >10,000 conjoins. This study focuses on reconstructing diachronic and synchronic changes in the chaîne opératoire of microliths production during the Epipaleolithic following refitting studies. The most significant contributions of this study are the realization that the Epipaleolithic cultural entities in the Negev all belong to the same conservative technological tradition, the Wide-fronted (W-fronted) approach to core exploitation and that changes were gradual. Still, several diachronic and synchronic differences within the microliths production sequences between the industries were also observed. By contrast, typological changes were more rapid. Each cultural entity is distinguished by discrete morphological types of microliths that appear over a relatively short time span of 1000-2000 14C years. Finally, this research provides further evidence supporting the validity of refitting studies as a significant methodological tool used to refine technological and typological classifications.
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The late Pleistocene (~75,000-15,000 years ago) is a key period for the prehistory of the Nile Valley. The climatic fluctuations documented during this period have led human populations to adapt to a changing Nile. In particular, major environmental changes in the Nile headwaters, such as the desiccation of some major eastern African lakes, influenced the Nile Valley environment —although how exactly is still debated— as is its role as an ecological refugium for human populations. In addition, while the Nile Valley is generally considered as a main ‘corridor’ of dispersals out of and back into Africa, differences in field methods and the terminology used hamper any systematic comparison between the Nile Valley and its neighbouring regions. This monograph groups together chapters presenting updated reviews and new data on regional archaeological, palaeoenvironmental, palaeoanthropological and geological records from north-eastern Africa and neighbouring regions (North Africa, eastern Africa and the Levant) for the period ranging from 75,000 to 15,000 years ago. Taking a multidisciplinary approach, this book allows the exploration of topical issues, such as modern humans’ capacity for adaptation, particularly in the context of climate change, as well as population interactions and human dispersals in the past.
Article
In 2010, a hominin right humerus fragment (KNM-RU 58330) was surface collected in a small gully at Nyamita North in the Late Pleistocene Wasiriya Beds of Rusinga Island, Kenya. A combination of stratigraphic and geochronological evidence suggests the specimen is likely between ∼49 and 36 ka in age. The associated fauna is diverse and dominated by semiarid grassland taxa. The small sample of associated Middle Stone Age artifacts includes Levallois flakes, cores, and retouched points. The 139 mm humeral fragment preserves the shaft from distal to the lesser tubercle to 14 mm below the distal end of the weakly projecting deltoid tuberosity. Key morphological features include a narrow and weakly marked pectoralis major insertion and a distinctive medial bend in the diaphysis at the deltoid insertion. This bend is unusual among recent human humeri but occurs in a few Late Pleistocene humeri. The dimensions of the distal end of the fragment predict a length of 317.9 ± 16.4 mm based on recent samples of African ancestry. A novel method of predicting humeral length from the distance between the middle of the pectoralis major and the bottom of the deltoid insertion predicts a length of 317.3 mm ± 17.6 mm. Cross-sectional geometry at the midshaft shows a relatively high percentage of cortical bone and a moderate degree of flattening of the shaft. The Nyamita humerus is anatomically modern in its morphology and adds to the small sample of hominins from the Late Pleistocene associated with Middle Stone Age artifacts known from East Africa. It may sample a population closely related to the people of the out-of-Africa migration.
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The architectural drawings of traditional building constructions generally require some design knowledge of the architectural plan to be understood. With the continuous development of the construction industry, the use of three-dimensional (3D) virtual models of buildings is quickly increased. Using three-dimensional models can give people a more convenient and intuitive understanding of the model of the building, and it is necessary for the painter to manually draw the 3D model. By analyzing the common design rules of architectural drawing, this project designed and realized a building three-dimensional reconstruction system that can automatically generate a stereogram (3 ds format) from a building plan (dxf format). The system extracts the building information in the dxf plan and generates a three-dimensional model (3 ds format) after identification and analysis. Three-dimensional reconstruction of architectural drawings is an important application of computer graphics in the field of architecture. The technology is based on computer vision and pattern recognition, supported by artificial intelligence, three-dimensional reconstruction, and other aspects of computer technology and engineering domain knowledge. It specializes in processing architectural engineering drawings with rich semantic information and various description forms to automatically carry out architectural drawing layouts. The high-level information with domain meanings such as the geometry and semantics/functions of graphics of the buildings can be analyzed for forming a complete and independent research system. As a new field of computer technology, the three-dimensional reconstruction drawings are appropriate for demonstrating the characteristics of architectural constructions.
Chapter
In 1990, during the initial field season of the Wembere-Manonga Paleontological Expedition (WMPE), the main characters of the structure, stratigraphy, paleoen-vironment, and geological history of the Neogene lake basin in the Manonga Valley were outlined. As only a small fraction of the extensive lake basin (covering approximately 10,000 km2) could be explored during this brief reconnaissance, lasting only about 15 days, geological work was concentrated at Tinde, and at neighboring paleontological sites in the center of the Manonga Valley. Preliminary results of this research have already been published by Harrison et al. (1993) and Harrison and Verniers (1993). More recently, during the summer of 1994, the author was able to study the stratigraphy in most of the outcropping areas in the Manonga Valley. As a consequence, a more detailed review of the stratigraphical results obtained from these two field seasons is presented in this chapter.
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To better understand the potential role of environmental change in mediating human dispersals across equatorial East Africa, this study examines the biogeographic histories of ungulates, including a summary of current knowledge and fossil evidence stemming from our fieldwork in the Kenyan portion of the Lake Victoria basin. Phylogeographic and paleontological evidence indicates that vegetation changes across Quaternary climate cycles mediated ungulate distributions and dispersals via the opening and closing of biogeographic barriers in equatorial East Africa. Dispersal capabilities would have been enhanced during phases of grassland expansion and diminished during phases of grassland contraction. We propose that the distribution and dispersal of diagnostic technological markers in the archaeological record may be similarly influenced by environmental changes. The Middle Stone Age record from the Lake Victoria region provides intriguing examples of possible environmentally mediated technological dispersals.
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The effect of changing environment on the evolution of Homo sapiens is heavily debated, but few data are available from equatorial Africa prior to the last glacial maximum. The Karungu deposits on the northeast coast of Lake Victoria are ideal for paleoenvironmental reconstructions and are best studied at the Kisaaka site near Karunga in Kenya (94 to N33 ka) where paleosols, fluvial deposits, tufa, and volcaniclastic deposits (tuffs) are exposed over a ~2 km transect. Three well-exposed and laterally continuous paleosols with intercalated tuffs allow for reconstruction of a succession of paleocatenas. The oldest paleosol is a smectitic paleo-Vertisol with saline and sodic properties. Higher in the section, the paleosols are tuffaceous paleo-Inceptisols with Alfisol-like soil characteristics (illuviated clay). Mean annual precipitation (MAP) proxies indicate little change through time, with an average of 764 ± 108 mm yr −1 for Vertisols (CALMAG) and 813 ± 182 to 963 ± 182 mm yr −1 for all paleosols (CIA-K). Field observations and MAP proxies suggest that Karungu was significantly drier than today, consistent with the associated faunal assemblage, and likely resulted in a significantly smaller Lake Victoria during the late Pleistocene. Rainfall reduction and associated grassland expansion may have facilitated human and faunal dispersals across equatorial East Africa.
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A large stable isotope dataset from East and Central Africa from ca. 30 regional collection sites that range from forest to grassland shows that most extant East and Central African large herbivore taxa have diets dominated by C4 grazing or C3 browsing. Comparison with the fossil record shows that faunal assemblages from ca. 4.1-2.35 Ma in the Turkana Basin had a greater diversity of C3-C4 mixed feeding taxa than is presently found in modern East and Central African environments. In contrast, the period from 2.35 to 1.0 Ma had more C4-grazing taxa, especially nonruminant C4-grazing taxa, than are found in modern environments in East and Central Africa. Many nonbovid C4 grazers became extinct in Africa, notably the suid Notochoerus, the hipparion equid Eurygnathohippus, the giraffid Sivatherium, and the elephantid Elephas. Other important nonruminant C4-grazing taxa switched to browsing, including suids in the lineage Kolpochoerus-Hylochoerus and the elephant Loxodonta. Many modern herbivore taxa in Africa have diets that differ significantly from their fossil relatives. Elephants and tragelaphin bovids are two groups often used for paleoecological insight, yet their fossil diets were very different from their modern closest relatives; therefore, their taxonomic presence in a fossil assemblage does not indicate they had a similar ecological function in the past as they do at present. Overall, we find ecological assemblages of C3-browsing, C3-C4-mixed feeding, and C4-grazing taxa in the Turkana Basin fossil record that are different from any modern ecosystem in East or Central Africa.
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The origins of modern humans have been the central debate in palaeoanthropology during the last decade. We examine the problem in the context of the history of anthropology, the accumulating evidence for a recent African origin, and evolutionary mechanisms. Using a historical perspective, we show that the current controversy is a continuation of older conflicts and as such relates to questions of both origins and diversity. However, a better fossil sample, improved dates, and genetic data have introduced new perspectives, and we argue that evolutionary geography, which uses spatial distributions of populations as the basis for integrating contingent, adaptive, and demographic aspects of microevolutionary change, provides an appropriate theoretical framework. Evolutionary geography is used to explore two events: the evolution of the Neanderthal lineage and the relationship between an ancestral bottleneck with the evolution of anatomically modern humans and their diversity. We argue that the Neanderthal and modern lineages share a common ancestor in an African population between 350,000 and 250,000 years ago rather than in the earlier Middle Pleistocene; this ancestral population, which developed mode 3 technology (Levallois/Middle Stone Age), dispersed across Africa and western Eurasia in a warmer period prior to independent evolution towards Neanderthals and modern humans in stage 6. Both lineages would thus share a common large-brained ancestry, a technology, and a history of dispersal. They differ in the conditions under which they subsequently evolved and their ultimate evolutionary fate. Both lineages illustrate the repeated interactions of the glacial cycles, the role of cold-arid periods in producing fragmentation of populations, bottlenecks, and isolation, and the role of warmer periods in producing trans-African dispersals.
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Lithic technologies have been used to trace dispersals of early human populations within and beyond Africa. Convergence in lithic systems has the potential to confound such interpretations , implying connections between unrelated groups. Due to their reductive nature, stone artefacts are unusually prone to this chance appearance of similar forms in unrelated populations. Here we present data from the South African Middle Stone Age sites Uitpan-skraal 7 and Mertenhof suggesting that Nubian core reduction systems associated with Late Pleistocene populations in North Africa and potentially with early human migrations out of Africa in MIS 5 also occur in southern Africa during early MIS 3 and with no clear connection to the North African occurrence. The timing and spatial distribution of their appearance in southern and northern Africa implies technological convergence, rather than diffusion or dispersal. While lithic technologies can be a critical guide to human population flux, their utility in tracing early human dispersals at large spatial and temporal scales with stone artefact types remains questionable.
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The tephrostratigraphic framework for Pliocene and Early Pleistocene paleoanthropological sites in East Africa has been well established through nearly 50 years of research, but a similarly comprehensive framework is lacking for the Middle and particularly the Late Pleistocene. We provide the first detailed regional record of Late Pleistocene tephra deposits associated with artifacts or fossils from the Lake Victoria basin of western Kenya. Correlations of Late Pleistocene distal tephra deposits from the Wasiriya beds on Rusinga Island, the Waware beds on Mfangano Island and deposits near Karungu, mainland Kenya, are based on field stratigraphy coupled with 916 electron microprobe analyses of eleven major and minor element oxides from 50 samples. At least eight distinct distal tephra deposits are distinguished, four of which are found at multiple localities spanning >60 km over an approximately north to south transect. New optically stimulated luminescence dates help to constrain the Late Pleistocene depositional ages of these deposits. Our correlation and characterization of volcaniclastic deposits expand and refine the current stratigraphy of the eastern Lake Victoria basin. This provides the basis for relating fossil- and artifact-bearing sediments and a framework for ongoing geological, archaeological and paleontological studies of Late Pleistocene East Africa, a crucial time period for human evolution and dispersal within and out of Africa.
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Although the African Great Lakes are important regulators for the East African climate, their influence on atmospheric dynamics and the regional hydrological cycle remains poorly understood. This study aims to assess this impact by comparing a regional climate model simulation that resolves individual lakes and explicitly computes lake temperatures to a simulation without lakes. The Consortium for Small-Scale Modelling model in climate mode (COSMO-CLM) coupled to the Freshwater Lake model (FLake) and Community Land Model (CLM) is used to dynamically downscale a simulation from the African Coordinated Regional Downscaling Experiment (CORDEX-Africa) to 7-km grid spacing for the period of 1999–2008. Evaluation of the model reveals good performance compared to both in situ and satellite observations, especially for spatiotemporal variability of lake surface temperatures (0.68-K bias), and precipitation (2116 mm yr 21 or 8% bias). Model integrations indicate that the four major African Great Lakes almost double the annual precipitation amounts over their surface but hardly exert any influence on precipitation beyond their shores. Except for Lake Kivu, the largest lakes also cool the annual near-surface air by 20.6 to 20.9 K on average, this time with pronounced downwind influence. The lake-induced cooling happens during daytime, when the lakes absorb incoming solar radiation and inhibit upward turbulent heat transport. At night, when this heat is released, the lakes warm the near-surface air. Furthermore, Lake Victoria has a profound influence on atmospheric dynamics and stability, as it induces circular airflow with over-lake convective inhibition during daytime and the reversed pattern at night. Overall, this study shows the added value of resolving individual lakes and realistically representing lake surface temperatures for climate studies in this region.
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Specialized pastoralism developed ∼3 kya among Pastoral Neolithic Elmenteitan herders in eastern Africa. During this time, a mosaic of hunters and herders using diverse economic strategies flourished in southern Kenya. It has been argued that the risk for trypanosomiasis (sleeping sickness), carried by tsetse flies in bushy environments, had a significant influence on pastoral diversification and migration out of eastern Africa toward southern Africa ∼2 kya. Elmenteitan levels at Gogo Falls (ca. 1.9-1.6 kya) preserve a unique faunal record, including wild mammalian herbivores, domestic cattle and caprines, fish, and birds. It has been suggested that a bushy/woodland habitat that harbored tsetse fly constrained production of domestic herds and resulted in subsistence diversification. Stable isotope analysis of herbivore tooth enamel (n = 86) from this site reveals, instead, extensive C4 grazing by both domesticates and the majority of wild herbivores. Integrated with other ecological proxies (pollen and leaf wax biomarkers), these data imply an abundance of C4 grasses in the Lake Victoria basin at this time, and thus little risk for tsetse-related barriers to specialized pastoralism. These data provide empirical evidence for the existence of a grassy corridor through which small groups of herders could have passed to reach southern Africa.
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Kenya National Museums Lukenya Hill Hominid 1 (KNM-LH 1) is a Homo sapiens partial calvaria from site GvJm-22 at Lukenya Hill, Kenya, associated with Later Stone Age (LSA) archaeological deposits. KNM-LH 1 is securely dated to the Late Pleistocene, and samples a time and region important for understanding the origins of modern human diversity. A revised chronology based on 26 accelerator mass spectrometry radiocarbon dates on ostrich eggshells indicates an age range of 23,576–22,887 y B.P. for KNM-LH 1, confirming prior attribution to the Last Glacial Maximum. Additional dates extend the maximum age for archaeological deposits at GvJm-22 to >46,000 y B.P. (>46 kya). These dates are consistent with new analyses identifying both Middle Stone Age and LSA lithic technologies at the site, making GvJm-22 a rare eastern African record of major human behavioral shifts during the Late Pleistocene. Comparative morphometric analyses of the KNM-LH 1 cranium document the temporal and spatial complexity of early modern human morphological variability. Features of cranial shape distinguish KNM-LH 1 and other Middle and Late Pleistocene African fossils from crania of recent Africans and samples from Holocene LSA and European Upper Paleolithic sites.
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The effect of changing palaeoclimate and palaeoenvironment on human evolution during the Pleistocene is debated, but hampered by few East African records directly associated with archaeological sites prior to the Last Glacial Maximum. Middle to Late Pleistocene deposits on the shoreline of eastern Lake Victoria preserve abundant vertebrate fossils and Middle Stone Age arte-facts associated with riverine tufas at the base of the deposits, which are ideal for palaeoenvironmental reconstructions. New data from tufas identified on Rusinga Island and on the mainland near Karungu, Kenya are provided from outcrop, thin sections, mineralogical, stable isotopic and U-series dating analyses. Tufa is identified in four sites: Nyamita (94·0 ± 3·3 and 111·4 ± 4·2 ka); Kisaaka, Aringo (455 ± 45 ka); and Obware. The age ranges of these tufa deposits demonstrate that spring-fed rivers were a recurrent, variably preserved feature on the Pleistocene landscape for ca 360 kyr. Poor sorting of clastic facies from all sites indicates flashy, ephemeral discharge, but these facies are commonly associated with barrage tufas, paludal environments with δ13C values of ca 10‰ indicative of C3 plants and fossil Hippopotamus, all of which indicate a perennial water source. Other tufa deposits from Nyamita, Obware and Aringo have a mixed C3/C4 signature consistent with a semi-arid C4 grassland surrounding these spring-fed rivers. The δ18O values of tufa from Nyamita are on average ca 1‰ more negative than calcite precipitated from modern rainfall in the region, suggesting greater contribution of depleted monsoonal input, similar to the Last Glacial Maximum. Microdebitage and surface-collected artefacts indicate that early modern humans were utilizing these spring-fed rivers. The presence of spring−fed rivers would have afforded animals a reliable water source, sustaining a diverse plant and animal community in an otherwise arid environment.
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The traditional utilization of wild food plants by the Suiei Dorobo of the Mathew's Range, northern Kenya, is described and analyzed in relation to the vegetation.(1) The vegetation of the Mathew's Range is described as being characterized by medium and drier types of montane forest and Mimosoideae savanna.(2) One hundred and twenty-two food plant species of the Suiei Dorobo are listed and graded into 1) major food, 2) important food and 3) complementary food, according to the relative importance in the traditional diet. Seasonal changes of ten major foods are also shown.(3) The food plants are classified into 1) forest type, 2) savanna type and 3) common type, in order to evaluate the vegetation from the viewpoint of food availability. It is concluded that the savanna is richer than the forest in the availability of the plant foods and game.(4) A comparison of vegetable foods of African hunter-gatherers is made by employing ITANI's classification (1974a) of African hunter-gatherers and vegetation types. The result is that the major vegetable foods of African hunter-gatherers roughly correspond to the vegetation types.
Article
The Kibish Formation of southern Ethiopia has yielded the earliest fossils of Homo sapiens, ca. 196 ka, and has thus figured prominently in discussions of the origins of modern humans. Here we describe the fossil Bovidae from the Kibish Formation, a record that spans the late Middle Pleistocene to the early to mid-Holocene, and reconstruct aspects of their dietary ecology using mesowear analyses. All of the Kibish bovids represent extant taxa with the exception of the extinct blesbok-like alcelaphin Damaliscus hypsodon; extinct arid-adapted forms Syncerus antiquus and Megalotragus, common in other Late Quaternary sites, are notably absent. Mesowear of the Kibish bovids suggests that the Late Quaternary specimens were characterized by diets with considerably more abrasion-dominated wear relative to their extant conspecifics. Finally, the Kibish record provides supporting evidence for recent phylogeographic hypotheses by demonstrating significant range expansions of Aepyceros melampus, Connochaetes taurinus, Hippotragus equinus, and, to a lesser extent, Kobus kob in the late Middle Pleis-tocene through the early to mid-Holocene coincident with humid phases that punctuated dry spells of the Late Quaternary.
Article
The development of savanna-type grasslands is a relatively recent phenomena in East Africa. The stable carbon isotopic composition of paleosol carbonates from fossil localities in East Africa show that C 4 vegetation was present by about 8-9 Ma but made up only a relatively small proportion of the total biomass. Although the proportion of C 4 vegetation increased in the Pliocene and Pleistocene there is no evidence for the development of virtually pure C 4 grasslands, as is characterized by tropical grasslands today, until Middle Pleistocene times. This has important implications concerning the evolution of mammals in Africa, including hominids.
Chapter
Although the Nile is an ancient river (see ch. 1 and 2), the existing hydrologic pattern is no older than 12,500 years and may be as young as 10,000 years. Even during that shorter period there have been drastic changes in the basic nature of the river, and its drainage area was sometimes augmented by overflow from the Lake Rudolf basin through the Pibor and Sobat rivers.
Chapter
Six piston cores from offshore Lake Victoria were analyzed for abundance of biogenic Si. Lake Victoria completely dried up during the last glacial maximum and began to refill around 12,400 radiocarbon years ago (12.4 ka). The abundance of biogenic Si rose immediately in the lacustrine sediments that accumulated over the paleosol, to the highest values observed in Holocene sediments, until about 7.4 ka when they dropped abruptly and remained low until 5.9 ka. They rose to intermediate values by 5.5 ka, after which time the profiles in the cores diverge, depending on their location in the lake. The simultaneous rise and fall in biogenic silica values observed across the entire lake basin between 12.4 and 5.5 ka cannot be attributed solely to changes in primary productivity. A model of the geochemical mass balance of Si in this system indicates that it could not support such widespread change for more than two to three decades. We interpret the biogenic Si profiles to be a record of changing supply rate of dissolved Si early in the new lake’s history, and to changes in lake level. The lake remained a closed basin until 7.4 ka, when oxygen isotopic data on aquatic cellulose indicate that it rose to its highest level, 18 m above present, and outflow was initiated. This resulted in an abrupt drop in biogenic Si accumulation at core sites throughout the lake because much of the Si could exit with the outflow. Downcutting at the Nile outlet resulted in a drop in lake level and focusing of diatom deposition in offshore basins. The lake finally stabilized around 5.5 ka. Subsequent shifts in biogenic Si profiles in the cores are attributed either to a spatially heterogeneous pattern of diatom productivity or to sediment focusing effects.
Article
This paper describes the fluctuations of Lakes Victoria, Stefanie, Turkana and Naivasha over the last two centuries. A chronology of Lake Victoria back to 700 A.D. is also developed. These chronologies are based mainly on oral traditions of the local peoples, as described in various historical sources, and on reports of European visitors, settlers and explorers. In some cases actual historical levels have been reported. The historical fluctuations are meshed with the modern record to provide a picture of the fluctuations in lake levels until the late twentieth century. The chronologies for Victoria and Stefanie contain much new material, permitting higher temporal resolution and better quantitative assessments, as well as extension of chronologies to the beginning of the 19th century. For Lakes Turkana and Naivasha, chronologies published by other authors are expanded and compared with those for Victoria, Stefanie and other African lakes. A long term chronology for Lake Victoria is developed using the record of the summer Nile flow. These lakes show remarkably similar trends. The most important of these trends are low levels during the first half of the 19th century, very high stands in the last decades of the 19th century, and around the turn of the century a rapid fall to 20th century levels. The lakes returned to relatively high stands in the 1960s, but these generally ended in the 1970s.
Article
Reviews previous notions of what might cause speciation and extinction, and hypotheses that have predicted temporal patterns of evolutionary events. Discusses a new postulate relating to the 'turnover-pulse' (a concentration of turnover events against the time scale), arguing that global climatic forcing of speciation rhythms has been of major importance to the diversification of mammals on the huge continental landmass of Africa in the Neogene. The turnover-phase hypothesis uses concepts of evolutionary conservation, species' habitat-specificity and vicariance. -P.J.Jarvis
Article
The level of Lake Victoria rose by over 2.5m between October 1959 and May 1964. Following a slight fall the lake began to rise again in 1978 and by mid 1979 had again reached almost to the level of 1964. Examines possible manmade and natural causes for the rises and opts for an increase in over-lake precipitation as the most likely cause. -from Author
Article
The extent to which the earliest anatomically modern humans in Africa exhibited behavioral and cognitive traits typical of Home sapiens sapiens is controversial. In eastern Zaire, archaeological sites with bone points have yielded dates older than 89(-15)(+22) thousand years ago by several techniques. These include electron spin resonance, thermoluminescence, optically stimulated luminescence, uranium series, and amino acid racemization. Faunal and stratigraphic data are consistent with this age.
Article
Occupation of the site at Songhur was of short or medium duration in the late Pleistocene. River erosion revealed tools and bones resembling those of the Stone Age in Kenya and east Uganda. The presence of obsidian indicates contact with people from the Rift Valley. Bones identified were from large Bovidae and rhinoceros. The exact age of the site cannot yet be estimated. -J.J.Robertson
Article
This preliminary report is the result of an archaeological expedition to Uganda, which took place from February to April 1968, and was sponsored by the Musée royal de l'Afrique centrale at Tervuren (Belgium) and the Comité des Fouilles beiges en Afrique. The expedition staff consisted of Dr F. Van Noten and Mr E. Vertriest of the department of Prehistory at the Tervuren Museum, and the author. The voluntary help of Miss J. Renard during the excavations is gratefully acknowledged here, as well as the advice of Professor M. Posnansky and the administrative assistance of Mr P. Bulenzi of the Uganda Ministry of Culture and Community Development. Much useful information was given by Mrs M. McFarlane of the Uganda Geological Survey, who has elsewhere pointed out the archaeological importance of the Buvuma Island group (McFarlane, 1968). Mrs McFarlane also deposited a series of Sangoan implements in the Uganda Museum. All drawings in this paper are by Miss N. Nypels. The islands of Buvuma and Bugaia form part of the archipelago situated near the northern shore of Lake Victoria southeast of Jinja and about halfway between Entebbe and the Kavirondo Gulf. Both islands lie immediately to the North of the Equator, approx. between 0°00′–0°15′ North and 33°15′–33°20′ East, Bugaia being to the southwest of Buvuma (see the 1: 50.000 Dept. of Lands and Surveys map, Magyo, series Y 732, sheet 72/4, edition I-U.S.D.). As will be apparent from this report, several interesting sites were encountered on both islands, two of which were excavated, one on Buvuma and one on Bugaia.
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The opening and closing of the equatorial East African forest belt during the Quaternary is thought to have influenced the biogeographic histories of early modern humans and fauna, although precise details are scarce due to a lack of archaeological and paleontological records associated with paleoenvironmental data. With this in mind, we provide a description and paleoenvironmental reconstruction of the Late Pleistocene Middle Stone Age (MSA) artifact- and fossil-bearing sediments from Karungu, located along the shores of Lake Victoria in western Kenya. Artifacts recovered from surveys and controlled excavations are typologically MSA and include points, blades, and Levallois flakes and cores, as well as obsidian flakes similar in geochemical composition to documented sources near Lake Naivasha (250 km east). A combination of sedimentological, paleontological, and stable isotopic evidence indicates a semi-arid environment characterized by seasonal precipitation and the dominance of C4 grasslands, likely associated with a substantial reduction in Lake Victoria. The well-preserved fossil assemblage indicates that these conditions are associated with the convergence of historically allopatric ungulates from north and south of the equator, in agreement with predictions from genetic observations. Analysis of the East African MSA record reveals previously unrecognized north-south variation in assemblage composition that is consistent with episodes of population fragmentation during phases of limited dispersal potential. The grassland-associated MSA assemblages from Karungu and nearby Rusinga Island are characterized by a combination of artifact types that is more typical of northern sites. This may reflect the dispersal of behavioral repertoires-and perhaps human populations-during a paleoenvironmental phase dominated by grasslands. Copyright © 2015 Elsevier Ltd. All rights reserved.
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(1) The effects of disturbance-depth and grazing on succession, spatial heterogeneity and species revegetation patterns were investigated in four grasslands (short, mid, tall and mosaic) in the Serengeti National Park, Tanzania. Successional trajectories of vegetation on disturbed and control plots in grazed and ungrazed blocks and plot variability were derived from detrended correspondence analysis. (2) All disturbances were revegetated by species of the original community and returned to their previous compositions 1-3 yr after disturbance. (3) After the elimination of grazing, short and sexually-reproducing species disappeared from the short- and mid-grass communities, which became dominated by tall, vegetatively-reproducing species. The mosaic and tall-grass communities were unchanged. Vegetation on the disturbed plots in both grazed and ungrazed blocks resembled the species composition and structure of the surrounding undisturbed vegetation. (4) Within-treatment plot heterogeneity increased over 5 yr in a community that was dominated by vegetatively-spreading species but decreased in communities dominated by caespitose species. (5) Patterns of colonization and succession in the undisturbed plots supported Gleason's `individualistic' concept.
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Hominins from Europe and Africa shed light on functional adaptations and other aspects of lifeways during the Middle Paleolithic. By the end of that time span, Neanderthals and modern humans clearly differed physically and perhaps behaviorally. Explanations of the anatomical differences have largely focused on adaptation (directional selection) to climate and habitual activity, but it is hard to rule out the alternative of genetic drift. Drift would have accelerated during periods of low population numbers, while selection operates best when populations are large and expanding. Demographic changes almost certainly tracked climatic conditions in both continents. Environmental and genetic data suggest that European hominins were primarily shaped by drift, while both factors operated in Africa.
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Eastern Africa is an important area to study early populations of Homo sapiens because subsets of those populations likely dispersed to Eurasia and subsequently throughout the globe during the Upper Pleistocene. The Middle Stone Age (MSA) archaeology of this region, particularly aspects of stone-tool technology and typology, is highly variable with only rare cases of geographic and temporal patterning. Although there are differences in timing and perhaps frequency of occurrence, those elements that make up the MSA lithic tool kit are also found at contemporaneous sites elsewhere in Africa and Eurasia, making it difficult to identify a unique archaeological signal for hominin dispersals out of eastern Africa. Rather, regional variation appears to be the outcome of possibly long-term interactions between particular physical and social environments experienced by hominin populations.