Article

The fossil history of Grevy's zebra (Equus grevyi) in Equatorial East Africa

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Abstract

Within the last several decades, Grévy's zebra (Equus grevyi) has undergone a massive reduction in geographical range and population size, largely as the result of human impacts. To place its recent decline in a deeper prehistoric context, and to understand the factors mediating its range and abundance over geological time frames, this study examines the fossil history of Grévy's zebra in equatorial East Africa. Equatorial East Africa. Presence/absence data for ungulates recovered from fossil sites spanning the last c. 400,000 years in Kenya and Ethiopia were compiled from the literature and from previously unreported palaeontological sites. Associations between Grévy's zebra and other taxa were examined using principal coordinates analysis and non-random species pairs were identified using a Bayesian approach. Changes in rainfall were reconstructed using the average hypsodonty index of ungulate species from fossil assemblages. Grévy's zebra was common during dry phases of the Pleistocene and was found to the south and west of its historical range, coinciding with an expansion of arid grasslands. At the onset of the Holocene, Grévy's zebra was extirpated from southern Kenya and almost completely disappeared from the fossil record. Grévy's zebra was associated with several specialized grazers that became extinct by the end of the Pleistocene. These extinctions and the decline of Grévy's zebra from the Pleistocene to the Holocene are explained by increased precipitation and the consequent loss of arid grasslands at the Pleistocene–Holocene transition. Grévy's zebra is never associated with domestic livestock, unlike the widespread plains zebra. Grévy's zebra thrived in equatorial East Africa during periods of the Pleistocene when environmental conditions favoured an expansion of arid grasslands. Environmental change across the Pleistocene–Holocene transition contributed to decreases in the range size and abundance of Grévy's zebra, setting the stage for the anthropogenic decline observed in recent decades. The spread of pastoralists in the middle Holocene may have additionally contributed to its prehistoric decline. Contemporary climate change warrants further consideration in planning for the long-term survival of Grévy's zebra.

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... Initial archaeological and paleontological explorations were conducted by Owen (1937Owen ( , 1938 and later by Pickford (1986), who surveyed and mapped the Pleistocene deposits. Recent investigations of these deposits in 2011-2012 documented MSA artifacts and a rich fossil assemblage similar to that recovered from Rusinga Island (see appendix in Faith et al. 2013). The Pleistocene deposits from Karungu are lithologically similar to those from Rusinga Island (Beverly et al. 2012), and preliminary analyses of the tephra deposits at Karungu document stratigraphic correlations between the two sites , suggesting that they are of the same age. ...
... falls solely within the range of grazing ungulates that inhabit open grasslands (Damuth and Janis 2011). A greater reliance on grasses and grassland habitats is consistent with the associated faunal communities at Rusinga Island and Karungu, which suggest the presence of open and seasonally arid grassland habitats (Tryon et al. 2010Faith et al. 2011Faith et al. , 2012Faith et al. , 2013. ...
... Such evolutionary change could reflect a greater reliance on open habitats compared to A. melampus or the mechanical demands of consuming dry grasses and grit. Although the extinction chronology is only secure for D. hypsodon and S. antiquus, it has been proposed that increased rainfall at the onset of the Holocene contributed to a loss of arid grasslands and increased competition with mesic-adapted species, leading to extinctions across the arid grassland community (Marean and Gifford-Gonzalez 1991;Marean 1992;Faith et al. 2011Faith et al. , 2012Faith et al. , 2013. In addition, the expansion of the equatorial forest belt (e.g., Cowling et al. 2008), driven by increased precipitation and rising atmospheric CO 2 levels, may have fragmented populations of grassland species and increased the likelihood of their extinction (see also Lorenzen et al. 2012). ...
Article
This study contributes to the growing complexity of the impala fossil record through a morphological description and analysis of Aepyceros fossils from late Pleistocene deposits in Kenya’s Lake Victoria Basin. We show that the Lake Victoria impala belongs to an extinct species that differs from modern impala and its fossil predecessors by a combination of exceptionally deep mandibles and teeth characterized by greater hypsodonty and occlusal lengths. Whereas modern impala (A. melampus) displays substantial ecological flexibility, these traits in the extinct species suggest a more dedicated adaptation to grazing in open and dry environments. Previous phylogeographic observations indicate that A. melampus was extirpated from East Africa, perhaps during the middle-to-late Pleistocene, and later recolonized from southern Africa. The Lake Victoria impala raises the possibility that the evidence interpreted as extirpation may instead reflect speciation, with A. melampus giving rise to a novel East African species while persisting unchanged in southern Africa. Increased rainfall and rising atmospheric CO2 concentrations at the end of the Pleistocene may have played a role in the disappearance of the extinct form via habitat loss and possibly competition with the more versatile A. melampus.
... Discussion-Grévy's zebra historically inhabited arid to semiarid grasslands and shrublands across the Horn of Africa (Williams, 2002), with their nearest occurrence >200 km from Kibogo in central Kenya. In the last ∼400,000 years, however, their distribution extended further south, occurring at numerous sites in southern Kenya and northern Tanzania (Faith et al., 2013). They are typically found with other arid-adapted taxa (e.g., Oryx) and are associated with extinct ungulates thought to prefer dry grassland habitats (e.g., Damaliscus hypsodon). ...
... The remaining non-analog associations relate to the considerable south-and westward expansion of Grévy's zebra during the Late Pleistocene (Faith et al., 2013). Today, Grévy's zebra occur no further south than central Kenya (Fig. 14), but it occurs in Late Pleistocene fossil assemblages throughout the eastern Lake Victoria Basin (Tryon et al., 2010Faith et al., 2015), as well as southern Kenya and northern Tanzania (Marean and Gifford-Gonzalez, 1991;Marean, 1992a). ...
... Today, Grévy's zebra occur no further south than central Kenya (Fig. 14), but it occurs in Late Pleistocene fossil assemblages throughout the eastern Lake Victoria Basin (Tryon et al., 2010Faith et al., 2015), as well as southern Kenya and northern Tanzania (Marean and Gifford-Gonzalez, 1991;Marean, 1992a). Given its strong association with arid-to semi-arid environments, together with suggestions that competition may preclude it from more mesic environments favored by plains zebra and wildebeest (Bauer et al., 1994;Rubenstein, 2010), these extralimital records are usually attributed to aridity and an expansion of dry grasslands (Faith et al., 2013). ...
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.
... Previous research has shown that the Pleistocene deposits surrounding Lake Victoria yield an abundance of well-preserved fossils and MSA ar-tefacts (e.g. Owen, 1937;Kent, 1944;Pickford, 1984;Behrensmeyer et al., 1995;Ditchfield et al., 1999;Plummer et al., 1999;Tryon et al., 2010Tryon et al., , 2012Tryon et al., , 2014Faith et al., 2011Faith et al., , 2012Faith et al., , 2013Faith et al., , 2014Van Plantinga, 2011;Garrett et al., in press). Stone artefacts from Rusinga Island and Karungu include flakes, blades, retouched points and Levallois cores, consistent with a MSA attribution Faith et al., in press b), the industry associated with the earliest modern humans. ...
... The fauna are dominated by alcelaphine bovids (wildebeest and allies) and equids, suggesting environments that were grassier and probably drier than the evergreen bushland, thicket and woodland found in the region today. Oryx (Oryx beisa) and Grevy's zebra (Equus grevyi), which prefer arid to semiarid grasslands and shrublands, and extinct antelopes adapted to grazing in dry grasslands, indicate that the environment was significantly more arid than at present (Tryon et al., 2010Faith et al., 2011Faith et al., , 2012Faith et al., , 2013Faith et al., , 2014. Carbon isotopes of mammalian tooth enamel indicate a diet of predominately C 4 grasses (Garrett et al., in press; Faith et al., in press b). ...
Article
Full-text available
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.
... The presence of arid-adapted species outside of their historic ranges, especially Grevy's zebra (Equus grevyi) and oryx (Oryx cf. beisa), is consistent with a reduction in precipitation (Faith et al., 2013), as is the dominance of extinct species characterized by exceptional hypsodonty (Faith et al., 2011. Drier conditions are further suggested by the geochemical composition of the paleosols at Kisaaka, which provide precipitation estimates of~760e960 mm/yr through the Late Pleistocene sequence (Beverly et al., 2015a). ...
... This allows us to examine the association between different strata and different species; when plotted in two dimensions, stratigraphic units with similar species compositions plot together, as do species with similar temporal trends in abundance. We use the primary axis (Axis 1) scores for each stratum to broadly summarize its species composition, and examine how these values change through time (as in Faith, 2013). Marean et al. (1994) previously observed that the size decline in EYM mole-rats tracks an increase in its abundance; we exclude mole-rats from the DCA to render it independent of this taxon. ...
... A grassland ecosystem is further supported by the locally abundant and wellpreserved sample of microfauna from Rusinga Island (NISP >50), which includes Tachyoryctes (African Mole Rat) and Otomys (Groove-Toothed Rat), with extant representatives of Tachyoryctes characteristics of open grasslands or thinly treed savannas (Kingdon, 1974;Nowak, 1999). Some extant taxa from Rusinga Island, such as the oryx (Oryx beisa) and Grevy's zebra (Equus grevyi), are distributed well beyond their modern ranges, suggesting range expansions or shifts during one or more arid intervals of the Pleistocene Faith et al., 2013). In light of the AE3 m variation in lake level since the late 19th century (Nicholson, 1998), the shallow (w5e10 m) and narrow (250 m) channel separating Rusinga Island is unlikely to have served as a long-term barrier to the movement of land animals between the island and the mainland. ...
... Tufas are sedimentary deposits formed by the precipitation of calcium carbonate minerals. In cool water systems, tufas typically contain the remains of microphytes, macrophytes, invertebrates, and bacteria that form in a persistent aqueous environment (Pedley, 1990;Ford and Pedley, 1996;Pedley et al., 2003). At Nyamita, on Rusinga Island (Fig. 1), multiple tufa deposits include a large fluvial barrage (Fig. 6A) and in situ stromatolites (Fig. 6B). ...
Article
Open-air archaeological sites record only a small fraction of the behavioral traces of mobile forager populations. Whereas caves and rockshelters were often occupied at least in part for protection from the elements, the reasons why human foragers occupied other places on the landscape (however briefly) are varied and not always readily recoverable. We develop a framework for interpreting human use of the landscape and modeling occupation of open-air sites using the archaeological and paleoenvironmental record of Middle Stone Age (MSA) sites from Rusinga and Mfangano Islands, located near the eastern margin of Lake Victoria. Paleoenvironmental reconstructions using fossil faunas suggest an arid grassland setting unlike the present. Paleoecological modeling of the habitats of extant and extinct bovids, combined with GIS-based reconstructions of lake level change, indicate that human occupation of these sites coincided with substantial declines in the level of Lake Victoria. During this time, both Rusinga and Mfangano would have been connected to the mainland and represented local topographic highs within an extensive grassland. Geological, ecological, and ethnobotanical observations suggest that these topographic high points would likely have been important sources of stone raw material, fresh water, and a variety of plant resources for food, fuel, and other purposes. In contrast, the grassy lowland plains were probably exploited primarily as a source of large game, which included numerous species of large gregarious grazers, several of which may have followed now extinct migration routes.
... However, the impact of these studies is limited because the relevant data archivesdparticularly proxies for temperature, moisture availability, and vegetationdare poorly resolved spatially and temporally (reviewed in Blome et al., 2012). Available faunal evidence indicates that early modern human populations in East Africa were part of extinct non-analog animal communities that were distinct in terms of taxonomic composition compared with regional modern mammal communities (Marean and Gifford-Gonzalez, 1991;Marean, 1992Marean, , 1997Tryon et al., 2010;Faith et al., 2011;Faith et al., 2012Faith et al., , 2013Faith et al., , 2014Tryon et al., 2012), and, as such, the paleoecology of these ancient populations remains poorly understood. Previous paleoenvironmental reconstructions of East African MSA sites using isotopic data have been restricted to the analysis of paleosols from site A5 (dated to~100e80 ka) at Aduma, Ethiopia (Yellen et al., 2005), and no published studies to date have examined the stable isotope composition of fossil mammals from this interval. ...
... The Pleistocene faunas from Rusinga and Mfangano (Table 1) contain the largest number of extinct species of any Pleistocene site in East Africa during the last~400 kyr (cf. Marean, 1992;Assefa et al., 2008;Domínguez-Rodrigo et al., 2008;Faith et al., 2011Faith et al., , 2012Faith et al., , 2013Faith et al., , 2014, with the extinct species Rusingoryx atopocranion (Pickford and Thomas, 1984;Faith et al., 2011) and Damaliscus hypsodon being the most abundant. Relevant to paleoenvironmental reconstruction, the faunas include several taxa indicating locally wet conditions, such as Hippopotamus and two species of reduncine bovids. ...
... The dominant bovids, R. atopocranion and D. hypsodon, are characterized by exceptional hypsodonty ( Faith et al., 2011Faith et al., , 2012), a probable adaptation to consuming grasses in dry and gritty environments ( Marean, 1992;Damuth and Janis, 2011). Drier conditions than present are further supported by the recovery of arid-adapted Grevy's zebra and oryx (Oryx beisa; Kingdon, 1982;Faith et al., 2013), although the presence of blue wildebeest suggests at least seasonal availability of moist grasses ( Skinner and Chimimba, 2005). Rare fossils of bushbuck (T. ...
... The presence of hippopotamus indicates at least some freestanding water and poses a puzzling contradiction, but their reliance on terrestrial forage may have allowed them to persist in very small springs similar to those documented on Rusinga Island (Tryon Beverly et al., in press), whereas crocodiles rely heavily on aquatic prey ( Corbet, 1960) and may have required larger water sources to support viable populations. Further evidence for drier conditions is provided by the presence of oryx and Grevy's zebra, which are adapted to arid to semi-arid environments and imply lower precipitation than at present ( Marean, 1992;Faith et al., 2013). Last, the dominance of extinct bovid species characterized by exceptional hypsodonty, a probable adaptation to feeding in open and dry environments ( Damuth and Janis, 2011), including D. hypsodon and R. atopocranion, is also consistent with reduced precipitation ( Eronen et al., 2010). ...
Article
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.
... Understanding how early human populations responded to such changes via geographic, demographic, or behavioral shifts are central goals of paleoanthropology (Barham and Mitchell, 2008;d'Errico and Stringer, 2011;Blome et al., 2012). While fieldwork in southern and western Kenya has greatly expanded our knowledge of paleoenvironments during arid phases of the Late Pleistocene (Marean and Gifford-Gonzalez, 1991;Marean, 1992aMarean, , 1992bFaith et al., 2013Faith et al., , 2014Faith et al., , 2015Tryon and Faith, 2013;Tryon et al., 2010Tryon et al., , 2014Tryon et al., , 2015, the paucity of paleoenvironmental data for humid intervals confounds our ability to address these questions. ...
... Indeed, the faunal communities of these sites are dominated by arid-adapted taxa, including the extinct alcelaphins Damaliscus hypsodon, Megalotragus, and Rusingoryx atopocranion, and the bovin Syncerus antiquus. In addition, these sites and others in northern Tanzania demonstrate range expansions of arid-adapted taxa such as Oryx beisa and Equus grevyi (Marean and Gifford-Gonzalez, 1991;Marean, 1992a;Faith et al., 2011Faith et al., , 2012Faith et al., , 2013Faith et al., , 2015Tryon et al., 2010Tryon et al., , 2014Tryon et al., , 2015. These ungulate taxa are either rare (D. hypsodon, O. beisa, E. grevyi) or absent (Megalotragus, R. atopocranion, S. antiquus) in the Kibish Formation. ...
Article
East Africa has produced the earliest record of Homo sapiens ~200ka and a punctuated record of Middle Stone Age and Later Stone Age behaviors. We lack, however, a detailed late Quaternary paleoenvironmental record for the region, particularly during humid periods. Without a regional record, hypotheses about the evolution and ecology of early Homo sapiens in East Africa remain vague and untestable. The Kibish Formation of southern Ethiopia presents a long, albeit punctuated, record of late Middle Pleistocene to Holocene faunal change in East Africa, which was deposited during humid periods. Here, we present oxygen and carbon stable isotope data of the Kibish ungulates and test whether there are environmental changes within the Kibish Formation. Significant differences in δ18O enamel isotopes are consistent with more humid conditions during the Holocene-age Member IV (~13-4ka) than either Pleistocene-age Member I (~196ka) or Member III (~104ka). Mesowear data document a shift toward more attritional wear among grazers in Member IV and are correlated with more depleted δ18O enamel values, suggesting that the wear pattern shift is linked to the onset of more humid conditions during the Holocene. δ13C enamel values show subtle variations through time, but do not suggest any major changes in diets. We propose that the paleoenvironmental differences evident in Member IV, based on δ18O enamel values, mesowear, and bovid abundances, may be explained by cooler and wetter conditions at the beginning of the Holocene in the lower Omo Valley. The evidence suggesting that the Holocene humid phase is more pronounced than earlier humid phases may explain why arid-adapted grassland ungulates became extinct in East Africa by the Pleistocene-Holocene transition, but persisted through previous humid phases of the late Quaternary.
... przewalskii) in Asia (Kaczensky et al. 2008), and Plains zebra and Grevy's zebra (E. grevyi) in parts of northern and central Kenya (Faith et al. 2013). The fossil record indicates that this partial sympatry extends back in time to the Middle Pleistocene and perhaps even earlier because Plains and Grevy's zebras are estimated to have diverged 1.5 million years ago (Vilstrup et al. 2013). ...
... East Africa experienced an increase in aridity and savannah grasslands approximately 600 000 years ago (deMenocal 2004). Grevy's zebras are adapted to arid grasslands (Faith et al. 2013), an environment with typically lower prey density that attracts lions (De Boer et al. 2010;Cain et al. 2011). Water-dependent archaic and modern humans (see Coss & Moore 1990;Reynolds et al. 2011) were similarly constrained in hunting more sparsely distributed game in drier habitats. ...
Article
Zebras, as prey species, attend to the behavior of nearby conspecifics and heterospecifics when making decisions to flee from predators. Plains zebras (Equus quagga) and Grevy's zebras (E. grevyi) frequently form mixed-species groups in zones where their ranges overlap in Kenya. Although anecdotal observations suggest that Plains zebras are more flighty around humans than Grevy's zebras are, this has not been empirically confirmed, and relatively little is known about how they may influence each other's flight behavior. We addressed these questions by examining the flight initiation distances (FIDs) of Plains and Grevy's zebras in single-species and mixed-species groups from an approaching human. One target individual per group was approached steadily on foot, with start distance, alert distance, and FID recorded from this target. Using start distance and alert distance separately as covariates, 22 Plains zebras in single-species groups exhibited a significantly longer mean FID than 15 Grevy's zebras in single-species groups. The FIDs of 7 Plains zebras and 5 Grevy's zebras tested in mixed-species groups were virtually equivalent and intermediate to those of Plains and Grevy's zebras in single-species groups, suggesting a bidirectional moderating influence of heterospecifics on risk assessment. This effect was most pronounced for Plains zebras in mixed-species groups that exhibited an FID that was significantly shorter than that of Plains zebras in single-species groups. Our findings underscore the importance of recognizing that related equids may be differently impacted by anthropogenic stress.
... The decline of the species from prehistory to the present day has been speculated upon and agonized over, and is generally believed to be largely as a result of human population expansion and competition for scarce water and forage resources, and predation. Undoubtedly these are important factors, however, Faith et al., 2013 reported on fossil history of Grevy's zebra indicating population decrease during the Pleistocene-Holocene era transition due to loss of arid grasslands. Current environmental conditions might suggest that this theory is still proximal to the cause of declining Grevy's zebra populations in the modern day. ...
... Redunca fulvorufula and R. redunca, T. scriptus and T. imberbis and Sylvicapra grimmia) are known from the Serengeti ecosystem today [65]. The Pleistocene assemblages include the highest frequencies of oryx (Oryx beisa), Grevy's zebra (Equus grevyi) and Damaliscuspossibly the extinct grassland species D. hypsodon, typically associated with oryx and Grevy's zebra-all taxa suggestive of habitats that are drier than today [66,67]. ...
Article
Increased population density is among the proposed drivers of the behavioural changes culminating in the Middle to Later Stone Age (MSA–LSA) transition and human dispersals from East Africa, but reliable archaeological measures of demographic change are lacking. We use Late Pleistocene–Holocene lithic and faunal data from Nasera rockshelter (Tanzania) to show progressive declines in residential mobility—a variable linked to population density—and technological shifts, the latter associated with environmental changes. These data suggest that the MSA–LSA transition is part of a long-term pattern of changes in residential mobility and technology that reflect human responses to increased population density, with dispersals potentially marking a complementary response to larger populations. This article is part of the themed issue ‘Major transitions in human evolution’.
... beisa) and Grévy's zebra (E. grevyi) that are characteristic of the SMCRE, suggesting westward dispersal during dry (i.e., glacial) conditions (Faith et al. 2013;Tryon et al. 2012). Hominin populations may well have followed a similar environmentally mediated pattern of range shifts. ...
Article
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.
... Africa is also home to a great diversity of species in 17 of the world's 20 orders of terrestrial mammals [19][20][21], and is virtually the only continent relatively unscathed by the late Quaternary extinction events [22,23]. Nevertheless, late Quaternary palaeoclimate change has been noted as a particularly important time period in the evolution and biogeography of African mammals [24][25][26][27][28][29][30][31][32][33][34][35], especially recurrent expansions and contractions of major vegetation biomes as climates changed [29,[36][37][38][39][40]. ...
Article
Ecological research often assumes that species are adapted to their current climatic environments. However, climate fluctuations over geologic timescales have influenced species dispersal and extinction, which in turn may affect community structure. Modern community structure is likely to be the product of both palaeoclimate and modern climate, with the relative degrees of influence of past and present climates unknown. Here, we assessed the influence of climate at different time periods on the phylogenetic and functional trait structure of 203 African mammal communities. We found that the climate of the mid-Holocene (approx. 6000 years ago) and Last Glacial Maximum (approx. 22 000 years ago) were frequently better predictors of community structure than modern climate for mammals overall, carnivorans and ungulates. Primate communities were more strongly influenced by modern climate than palaeoclimate. Overall, community structure of African mammals appears to be related to the ecological flexibility of the groups considered here and the regions of continental Africa that they occupy. Our results indicate that the future redistribution, expansion and contraction of particular biomes due to human activity, such as climate and land-use change, will differentially affect mammal groups that vary in their sensitivity to environmental change.
... For example, the record of Grevy's zebra (Equus greyvi) and beisa oryx (Oryx beisa) at Lukenya Hill and Lake Victoria is evidence for range expansions of both taxa during arid phases of the Pleistocene. Grevy's zebra and beisa oryx are united by adaptations to arid habitats and significantly co-occur in East African sites during the Pleistocene (Faith et al., 2013). The presence of Damaliscus hypsodon in the Kibish Formation provides evidence that this taxon was more widely distributed during the Middle to Late Pleistocene than previously recognized. ...
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.
... Africa is also home to a great diversity of species in 17 of the world's 20 orders of terrestrial mammals [19][20][21], and is virtually the only continent relatively unscathed by the late Quaternary extinction events [22,23]. Nevertheless, late Quaternary palaeoclimate change has been noted as a particularly important time period in the evolution and biogeography of African mammals [24][25][26][27][28][29][30][31][32][33][34][35], especially recurrent expansions and contractions of major vegetation biomes as climates changed [29,[36][37][38][39][40]. ...
Article
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Ecological research often assumes that species are adapted to their current climatic environments. However, climate fluctuations over geologic timescales have influenced species dispersal and extinction, which in turn may affect community structure. Modern community structure is likely to be the product of both palaeoclimate and modern climate, with the relative degrees of influence of past and present climates unknown. Here, we assessed the influence of climate at different time periods on the phylogenetic and functional trait structure of 203 African mammal communities. We found that the climate of the mid-Holocene (approx. 6000 years ago) and Last Glacial Maximum (approx. 22 000 years ago) were frequently better predictors of community structure than modern climate for mammals overall, carnivorans and ungulates. Primate communities were more strongly influenced by modern climate than palaeoclimate. Overall, community structure of African mammals appears to be related to the ecological flexibility of the groups considered here and the regions of continental Africa that they occupy. Our results indicate that the future redistribution, expansion and contraction of particular biomes due to human activity, such as climate and land-use change, will differentially affect mammal groups that vary in their sensitivity to environmental change. © 2016 The Author(s) Published by the Royal Society. All rights reserved.
... If additional finds confirm the presence of Grevy's zebra, this would contribute to an increasing number of Middle-Late Pleistocene fossils in areas far beyond this animal's historic range, a fact that has been linked to greater aridity and expanded grasslands at that time . Other fauna associated with Grevy's zebra in the Pleistocene fossil record, according to Faith et al. (2013), are white rhinoceros (Ceratotherium simum) and the giant long-horn buffalo (Syncerus antiquus). While our current sample is far too small and fragmented to permit identification of these taxa, it is notable that a complete metacarpal of a rhinoceros was identified in the 2013 collection, and three compact bones were attributed to either rhinoceros or hippopotamus. ...
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This paper describes the motivation, procedures, and results of archaeological and geological field survey of the Ndutu Unit, Olduvai Gorge, conducted in June and July of 2013. Survey focused upon the area of Olduvai Gorge between the second fault and the Olbalal, although selective survey occurred in other areas in and around the Gorge. Over 72 archaeological find-spots were recorded, and hundreds of Middle Stone Age (MSA) artifacts were recovered, as was a small sample of fauna. Geological observations provisionally suggest that the Ndutu was formed, in part, from a series of pyroclastic density flow and ash fallout events from neighbouring volcanoes; this contrasts slightly with previous interpretations of the deposits in that at least some of the beds are thought to be in primary stratigraphic context. Our initial field findings are conducive to discussions of a number of issues directly relevant to the MSA in East Africa, and overall we conclude that there is strong potential for Olduvai's Ndutu Unit to shed light on the behavior, adaptations, and evolution of Homo sapiens prior to, during, and just after its physical emergence.
... Data presented above show that the Late Pleistocene of the region is characterized by arid conditions that likely favored massive range expansions of some dry grassland species, including Dorcas gazelle and Grant's gazelle in the MER. The absence of these species from Holocene assemblages in the region suggests that, as may have been the case for other arid-adapted species in East Africa ( Faith et al., 2013), wetter conditions at the onset of the Holocene could have contributed to their extirpation from the region through habitat loss or competition with mesic-adapted ungulates. For D. hypsodon, these factors likely played a decisive role in its extinction. ...
... For example, the record of Grevy's zebra (Equus greyvi) and beisa oryx (Oryx beisa) at Lukenya Hill and Lake Victoria is evidence for range expansions of both taxa during arid phases of the Pleistocene. Grevy's zebra and beisa oryx are united by adaptations to arid habitats and significantly co-occur in East African sites during the Pleistocene (Faith et al., 2013). The presence of Damaliscus hypsodon in the Kibish Formation provides evidence that this taxon was more widely distributed during the Middle to Late Pleistocene than previously recognized. ...
... Sparse artifacts and abundant fauna from open-air sites on Rusinga Island, Kenya, highlight the association of MSA humans with a diverse and arid-adapted ungulate community (Tryon et al., 2010(Tryon et al., , 2012Faith et al., 2011Faith et al., , 2013Faith et al., , 2014Faith et al., , 2015Faith et al., , 2016Tryon and Faith, 2013;Blegen et al., 2015;Beverly et al., 2015a, b;Garrett et al., 2015). The Wakondo locality is one of three main Pleistocene collecting areas on Rusinga, and lies on the southeastern slope of the island (UTM: 36M 0630458, 9953261),~20 m above the modern lake level of Lake Victoria ( Fig. 1 A and B). ...
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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.
... Jim Simons examined portions of the faunal assemblage in the 1960s, as did Curtis Marean and Celeste Ehrhardt in the late 1980s [49][50][51]. These initial examinations indicated that the Late Pleistocene strata at Kisese II include the southernmost examples of the dry grassland taxa Grevy's zebra (Equus grevyi) and the extinct alcelaphine bovid Damaliscus hypsodon [51][52][53]. Impala (Aepyceros melampus) are present at Kisese II only in the uppermost 50 cm despite the fact that they are the dominant resident large mammal in nearby Tarangire National Park [37], implying key changes in regional habitats over time. Our current reconstructions of the Kisese II sequence began in 2011 and are based on Inskeep's sparse published notes on the site [31,42], material donated to us by his widow Adi, site photographs and artifact tallies retained by Inskeep now at the McDonald Archaeological Institute at Cambridge University, and new analyses of excavated lithic artifacts and fossil fauna stored at the National Museum of Tanzania (NMT) in Dar es Salaam, where they are un-numbered but accessible to other researchers. ...
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The archaeology of East Africa during the last ~65,000 years plays a central role in debates about the origins and dispersal of modern humans, Homo sapiens. Despite the historical importance of the region to these discussions, reliable chronologies for the nature, tempo, and timing of human behavioral changes seen among Middle Stone Age (MSA) and Later Stone Age (LSA) archaeological assemblages are sparse. The Kisese II rockshelter in the Kondoa region of Tanzania, originally excavated in 1956, preserves a ≥ 6-m-thick archaeological succession that spans the MSA/LSA transition, with lithic artifacts such as Levallois and bladelet cores and backed microliths, the recurrent use of red ochre, and >5,000 ostrich eggshell beads and bead fragments. Twenty-nine radiocarbon dates on ostrich eggshell carbonate make Kisese II one of the most robust chronological sequences for understanding archaeological change over the last ~47,000 years in East Africa. In particular, ostrich eggshell beads and backed microliths appear by 46–42 ka cal BP and occur throughout overlying Late Pleistocene and Holocene strata. Changes in lithic technology suggest an MSA/LSA transition that began 39–34.3 ka, with typical LSA technologies in place by the Last Glacial Maximum. The timing of these changes demonstrates the time-transgressive nature of behavioral innovations often linked to the origins of modern humans, even within a single region of Africa.
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Often conservationists suffer from the ‘shifting base line syndrome’. We illustrate this by elucidating the natural history of Tanzania’s northern Rift Valley over the past centuries. White rhinoceros and possibly the sable antelope went extinct five centuries ago. Two centuries ago Maasai cattle started competing with plains wildlife, but a reset took place through diseases. Wildlife’s zenith was around 1935, before commercial agriculture arose and before people and livestock had recovered from devastating epidemics. Elephant populations recovered from the ivory trade; wildlife benefitted from the expanding range of the tsetse fly. From the 1920s until the 1980s, cattle numbers soared and most fresh water became monopolized by farmers or pastoralists. Unlike in the Serengeti grasslands, the great herbivore migrations that could have developed after the rinderpest eradication were not attained in the grasslands of the northern Rift Valley: in fact, the wildebeest and zebra migrations to a large extent disappeared. It appears that conservationists who have fallen victim to the shifting baseline syndrome are content with the current impoverished natural state. Consequently, with the memory gone and baselines shifted, it is likely that the true natural state of the ecosystem of the northern Rift Valley will not be restored.
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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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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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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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Grevy's zebra (Equus grevyi) has been reported from fossil sites spanning the past 2.3 Myr and covering a wide geographic range. However, no currently published reports dating to >200 ka can be confidently attributed to E. grevyi, with most specimens better allocated to another taxon or lacking diagnostic characteristics aligning them with E. grevyi to the exclusion of other large Equus species such as E. oldowayensis. This leaves the origin of Grevy's zebra unresolved. Here, we describe a largely complete cranium of a large mare from the Kapthurin Formation in Kenya's Baringo Basin that represents the first definitive appearance of E. grevyi at 547.0e392.6 ka. This cranium falls within the range of variation for recent E. grevyi and is morphologically distinct from all other fossil and extant zebras. The new Kapthurin specimen has implications for the complex evolutionary history of large zebras. Furthermore, it provides insights into the mechanisms underpinning the expanded range of Grevy's zebra during the Pleistocene. Based on species distribution modeling and a multivariate analysis of its climate niche, we argue that the wide fossil distribution of E. grevyi may have had little to do with Pleistocene aridity as previously argued. Instead, the range contraction of Grevy's zebra may have been driven by competition with plains zebra (E. quagga) after the northward expansion of the latter species.
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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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Paleozoology and Paleoenvironments outlines the reconstruction of ancient climates, floras, and habitats on the basis of animal fossil remains recovered from archaeological and paleontological sites. In addition to outlining the ecological fundamentals and analytical assumptions attending such analyzes, J. Tyler Faith and R. Lee Lyman describe and critically evaluate many of the varied analytical techniques that have been applied to paleozoological remains for the purpose of paleoenvironmental reconstruction. These techniques range from analyses based on the presence or abundance of species in a fossil assemblage to those based on taxon-free ecological characterizations. All techniques are illustrated using faunal data from archaeological or paleontological contexts. Aimed at students and professionals, this volume will serve as fundamental resource for courses in zooarchaeology, paleontology, and paleoecology.
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The middle Pleistocene fossil mammal assemblage from Lainyamok in the southern Kenya rift has previously been considered the oldest (330–392 ka) African mammal community consisting entirely of extant species, with the dominant bovid tentatively attributed to the southern African blesbok (Damaliscus cf. dorcas). We show that the blesbok-like fossils from Lainyamok belong to an extinct species, described here as Damaliscus hypsodon sp. nov. The D. hypsodon hypodigm includes the previously unnamed small alcelaphine material known from late Pleistocene sites elsewhere in Kenya and Tanzania. Its dental anatomy, together with an ecomorphological analysis of its postcrania, indicates that D. hypsodon grazed in open and arid grassland environments. Although Lainyamok is no longer represented entirely by extant species, the absence of species common earlier in the middle Pleistocene of East Africa suggests substantial faunal turnover between 500 and 400 ka. Damaliscus hypsodon persisted in East Africa until the end of the Pleistocene and its extinction can be attributed to a loss of arid grassland environments at the onset of the Holocene. The fossil evidence from southern Kenya suggests that the development of the taxonomically modern large mammal community was a long-term process characterized by the extinction of grazing specialists, with marked turnover occurring between ~ 500 and 400 ka and near the end of the Pleistocene.
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Southern Africa’s Cape Floristic Region (CFR) is a global priority for conservation action, with 41 native large mammal species considered in ongoing conservation schemes. This study reviews historic and paleozoological evidence suggesting that an additional species – the roan antelope (Hippotragus equinus) – is native to the region and warrants consideration in conservation efforts. A single observation in 1778 suggests that a population of roan antelope formerly inhabited the CFR in the vicinity of Plettenberg Bay (Western Cape, South Africa). The fossil record is consistent with this observation, showing that roan antelope inhabited the southern coast of the CFR for the last ~20,000 years. Roan antelope were likely extirpated from the CFR during the late 1700s, broadly corresponding to the extinction of the blue antelope (H. leucophaeus) and the near-extinction of the bontebok (Damaliscus pygargus pygargus). If the goal of conservation efforts is to establish viable populations of extant species that are native to the region, then roan antelope is a prime candidate for conservation action and reintroduction to the CFR.
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This paper presents an overview of paleoenvironmental changes in East Africa during the late Quaternary based on evidence from pollen, diatoms, microscopic charcoal, and lake level records and associated proxies. The paleoenvironmental records derived from different proxies complement each other to provide a more accurate and complete assessment of the paleoenvironmental changes in East Africa. The records show that the period prior to c. 42,000 14 C yr BP was characterized by warm climatic conditions similar to the present. This was followed by a change to cold dry conditions from 42,000 to 30,000 14 C yr BP , and cold and moist conditions from 30,000 to 21,000 14 C yr BP . Temperatures during the latter period leading to the Last Glacial Maximum (LGM) were probably 2 to 4.1°C lower than the present. Between c. 21,000 and 12,500 14 C yr BP East Africa's environment was generally cool, punctuated by two significant episodes of prolonged desiccation. Warm and moist conditions punctuated by rapid climatic changes prevailed in the region during the deglacial and middle Holocene period. Ice core records document two significant and abrupt drought events in the region, one at ~8300 14 C yr BP and the other at 5200 14 C yr BP . The onset of a longer and more extensive desiccation period commencing ~4000 14 C yr BP was registered in nearly all sites. The climate of East Africa was generally drier than present during the Medieval Warm Period (MWP) while fairly wet conditions prevailed during the Little Ice Age (LIA) interrupted by three episodes of aridity, more severe than those of more recent times. Whereas this review advances our understanding of climate and vegetational changes in East Africa beyond the Last Glacial Maximum, it also highlights limitations of the paradigms that explain the forcing mechanisms behind the changes. However, unequivocal interpretation of the multiproxy data from East Africa with respect to paleoenvironmental changes becomes extremely complex and challenging especially when the anthropogenic input is considered.
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The purpose of this data set was to compile body mass information for all mammals on Earth so that we could investigate the patterns of body mass seen across geographic and taxonomic space and evolutionary time. We were interested in the heritability of body size across taxonomic groups (How conserved is body mass within a genus, family, and order?), in the overall pattern of body mass across continents (Do the moments and other descriptive statistics remain the same across geographic space?), and over evolutionary time (How quickly did body mass patterns iterate on the patterns seen today? Were the Pleistocene extinctions size specific on each continent, and did these events coincide with the arrival of man?). These data are also part of a larger project that seeks to integrate body mass patterns across very diverse taxa (NCEAS Working Group on Body Size in Ecology and Paleoecology: linking pattern and process across space, time, and taxonomic scales). We began with the updated version of D. E. Wilson and D. M. Reeder's taxonomic list of all known Recent mammals of the world (N = 4629 species) to which we added status, distribution, and body mass estimates compiled from the primary and secondary literature. Whenever possible, we used an average of male and female body mass, which was in turn averaged over multiple localities to arrive at our species body mass values. The sources are line referenced in the main data set, with the actual references appearing in a table within the metadata. Mammals have individual records for each continent they occur on. Note that our data set is more than an amalgamation of smaller compilations. Although we relied heavily on a data set for Chiroptera by K. E. Jones (N = 905), the CRC handbook of Mammalian Body Mass (N = 688), and a data set compiled for South America by P. Marquet (N = 505), these represent less than half the records in the current database. The remainder are derived from more than 150 other sources. Furthermore, we include a comprehensive late Pleistocene species assemblage for Africa, North and South America, and Australia (an additional 230 species). “Late Pleistocene” is defined as approximately 11 ka for Africa, North and South America, and as 50 ka for Australia, because these times predate anthropogenic impacts on mammalian fauna. Estimates contained within this data set represent a generalized species value, averaged across sexes and geographic space. Consequently, these data are not appropriate for asking population-level questions where the integration of body mass with specific environmental conditions is important. All extant orders of mammals are included, as well as several archaic groups (N = 4859 species). Because some species are found on more than one continent (particularly Chiroptera), there are 5731 entries. We have body masses for the following: Artiodactyla (280 records), Bibymalagasia (2 records), Carnivora (393 records), Cetacea (75 records), Chiroptera (1071 records), Dasyuromorphia (67 records), Dermoptera (3 records), Didelphimorphia (68 records), Diprotodontia (127 records), Hydracoidea (5 records), Insectivora (234 records), Lagomorpha (53 records), Litopterna (2 records), Macroscelidea (14 records), Microbiotheria (1 record), Monotremata (7 records), Notoryctemorphia (1 record), Notoungulata (5 records), Paucituberculata (5 records), Peramelemorphia (24 records), Perissodactyla (47 records), Pholidota (8 records), Primates (276 records), Proboscidea (14 records), Rodentia (1425 records), Scandentia (15 records), Sirenia (6 records), Tubulidentata (1 record), and Xenarthra (75 records).
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A comprehensive, but simple-to-use software package for executing a range of standard numerical analysis and operations used in quantitative paleontology has been developed. The program, called PAST (PAleontological STatistics), runs on standard Windows computers and is available free of charge. PAST integrates spreadsheettype data entry with univariate and multivariate statistics, curve fitting, time-series analysis, data plotting, and simple phylogenetic analysis. Many of the functions are specific to paleontology and ecology, and these functions are not found in standard, more extensive, statistical packages. PAST also includes fourteen case studies (data files and exercises) illustrating use of the program for paleontological problems, making it a complete educational package for courses in quantitative methods.
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This important paper offers a fresh and stimulating approach to the interpretation of a large faunal assemblage from an excavated site. There are interesting implications in regard to present-day land use—an aspect of archaeology to which too little attention has been paid. The principal author, Dr Gifford is Assistant Professor in The Board of Studies in Anthropology, University of California.SummaryThis paper reports in detail on the largest faunal assemblage yet analysed from a Pastoral Neolithic site. Prolonged Drift, located south of Lake Nakuru, Kenya, yielded over 160,000 pieces of bone, reflecting a mixture of wild and domestic species in one midden deposit. A substantial part of our discussion centres on the possible economic systems and practices that may have existed in the Central Rift during the first and second millennia B.C.
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Most of African's wildlife lives on landscapes inhabited by people. Nowhere is this more evident than on grasslands and savannas of arid areas where conflict between wildlife and livestock has always been common. In the past, economic development on these landscapes has eclipsed conservation, but in today's Africa, where pastoral herders and small-scale landholders seek enhanced lifestyles, understanding the links between behavior and ecology suggests that the demise of wildlife is not inevitable. Behavioral ecology offers insights into how features of the environment shape behavior. By unraveling the rules for particular species in particular environmental circumstances, it is possible to intervene and adjust peoples' behavior so that landscapes can be modified in ways that allow species to sustain themselves while improving human welfare. In this chapter I examine the socioecology of two zebra species—one thriving, the other verging on extinction–and show how resiliency emerges from understanding the link between a species' ecology and its behavior, demography, and population dynamics. I show that by working with large-scale commercial livestock ranchers, small-scale ranchers, and pastoral communities to apply basic behavioral ecological principles in context specific ways, balancing conservation and development is possible.
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Background: We developed a method to estimate precipitation using mammalian ecomorphology, specifically the relative height of the molars of herbivores (see companion paper, this issue). Question: If we apply the new method to paleoenvironments, do the results agree with previous results from fossil mammals and paleobotanical proxies? Data: Large herbivorous fossil mammals of Eurasia. Data from NOW database covers 23-22 Ma and is Eurasia-wide. Method: We apply the new precipitation estimation method (based on present-day mammalian ecomorphology) to fossil assemblages from different localities. Conclusions: The early Miocene retained the overall humid conditions of the late Paleogene. A shift to more arid conditions began during the middle Miocene. The late Miocene as a whole was a time of large changes, and there was continent-wide restructuring of the distribution of environments. Our new results agree with previous investigations and the mammal proxy data are in good agreement with palaeovegetation data. Mammals and vegetation produce similar precipitation values and large-scale patterns.
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Question: How can mammalian community characteristics be used to estimate regional precipitation? Data: Global distribution data of large mammals and their ecomorphology; global climate data. Research methods: Non-linear regression-tree analysis and linear regression. Conclusions: The methods unravelled the complex relationships between the environment and the characteristics of mammalian communities. The regression trees described here provide a reasonably accurate estimate of precipitation values for today's world. The strongest correlations are for annual precipitation versus diet (R 2 = 0.665), precipitation versus tooth crown height (R 2 = 0.658), and precipitation versus diet and tooth crown height combined (R 2 = 0.742)
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Surveys and excavations in 2009�2011 recovered fossil and artefact assemblages from late Pleistocene sediments on Rusinga and Mfangano islands (Lake Victoria, Kenya). Radiometric age estimates suggest that the Rusinga material dates to between 100 and 33 kya, whereas that from Mfangano may date to ]35 kya. The preservation of a large and diverse suite of vertebrate fossils is unusual for Pleistocene sites in the Lake Victoria region and the composition of the faunal assemblages from both islands strongly suggest an open, arid, grassland setting very different from that found inwesternKenya today.Middle Stone Age(MSA) artefacts fromRusinga and possible Later Stone Age (LSA) or MSA/LSA assemblages from Mfangano are distinct from Lupemban MSA sites characteristic of the Lake Victoria region and instead share a number of typological and technological features with late Pleistocene sites from open grassland settings in the East African Rift System. This highlights the complex roles that shifting environments, as well as temporal change, may have played in the development of regional variation among EquatorialAfrican artefact assemblages in the Pleistocene. Keywords: Middle Stone Age; Later Stone Age; Quaternary; aridity; Lake Victoria
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The African long-horned buffalo, Pelorovis antiquus, was once widespread in the savannas and grasslands of southern, eastern, and northern Africa. It apparently disappeared from southern and eastern Africa about 12,000 years ago and from northern Africa about 4000 years ago. Its extinction has been variously attributed to human predation, climatic change, or some combination of the two. Recently, Peters et al. (Late Quaternary extinction of ungulates in Sub-Saharan Africa: a reductionist's approach, Journal of Archaeological Science 21, 17-28, 1994) argued that its demise has been exaggerated and that its postcranial anatomy indicates it was simply a long-horned morph of the extant African buffalo, Syncerus caffer. Both cranial and postcranial similarities to Syncerus can be used to suggest that P. antiquus should be removed from Pelorovis and reassigned to Syncerus, as Syncerus antiquus. However, its status as a distinct (and now extinct) buffalo species is demonstrated by its singular horns, by some dental differences from S. caffer, and above all, by its geographic overlap with S. caffer through much of the middle and late Quaternary, with no evidence for intermediate forms.
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Climatic changes may have played a role in extinction of species in Africa, but these species had survived similar climatic changes in earlier periods. Two differences were in the composition of communities and the kind of people present. The cause of extinctions in the Lower and Middle Pleistocene may never be resolved. Even if man was not responsible for 'overkill' in the Late Quaternary their own attempts to adjust to a changing environment may have perturbed the system sufficiently so that species did disappear which otherwise may have survived.-T.M.Kennard
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THERE has been considerable debate about the magnitude of the decrease in temperature1,2 and the change in precipitation3 in the African tropics during the last glacial period. With the advent of fossil pollen studies in equatorial regions, it is now generally agreed that the temperature did decrease at this time in tropical regions4, but the magnitude of the temperature fluctuations and discrepancies between the continental5 and marine6 temperature records have yet to be resolved7. Here we present new quantitative estimates of temperature and precipitation using a multivariate analysis8 of pollen time-series data from peat deposits in Burundi for the past 40,000 years9. For the last glacial period, our estimate of a temperature decrease of 4 +/- 2 °C is less than those (ranging from 5 to 8 °C) derived from snow-line and tree-line records5,7. Model simulations7 indicate that the snow-line and tree-line estimates (from high-elevation sites at ~4,000 m above sea level) are incompatible with the marine temperature record. Our lower estimate from a site of intermediate elevation may help resolve the differences between these records. We also estimate that the mean annual rainfall decreased by 30% during the last glacial period, in agreement with the rainfall history inferred from lake level fluctuations10.
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Aim To test whether congeneric species are significantly associated with one another in space, either positively or negatively. Also, to provide a framework for a causal investigation of co-occurrence patterns by a parallel comparison of interactions in geographical and ecological data matrices.Location For the analysis of congeneric species’ co-occurrences we used 30 matrices covering a wide range of taxa and geographical areas, while for the causal investigation we used the distribution of 50 terrestrial isopod species on 20 islands and 264 sampling stations in the central Aegean archipelago, as well as a number of ecological variables for each sampling station.Methods We developed a software program (cooc) that incorporates the species-by-species approach to co-occurrence analysis using EcoSim's output of prior null model analysis of co-occurrence. We describe this program in detail, and use it to investigate one of the most common assembly rules, namely, the decreased levels of co-occurrence among congeneric species pairs. For the causal analysis, we proceed likewise, cross-checking the results from the geographical and the ecological matrices. There is only one possible combination of results that can support claims for direct competition among species.Results We do not get any strong evidence for widespread competition among congeneric species, while most communities investigated do not show significant patterns of species associations. The causal analysis suggests that the principal factors behind terrestrial isopod species associations are of historical nature. Some exceptional cases are also discussed.Main conclusions Presence/absence data for a variety of taxa do not support the assembly rule that congeneric species are under more intense competition compared to less related species. Also, these same data do not suggest strong interactions among species pairs, regardless of taxonomic status. When significant species associations can be seen in such matrices, they mainly reflect the effects of history or of habitat requirements.
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The extinct Cape zebra (Equus cupensis Broom) was first described from the Cape Town region of South Africa in 1909. Subsequent materials were reported from the hinterland of the Cape and into the Orange Free State, with records from Zimbabwe and Zambia, and 18 species were named. These were synonymised with the type binomial. Populations similar to the Cape zebra were described in East Africa as E. oldowayensis. Recently, specimens, also referable to the Cape zebra, have been recovered from Late Pleistocene and Holocene deposits in Dakhleh Oasis, Egypt, northwest Africa. The known temporal range of these Cape zebra populations is from Late Pliocene in East and South Africa and from Late Pleistocene in Egypt, to Middle Holocene in northeast and South Africa, and to Recent in northern Kenya, southern Ethiopia and the northeast of southern Somalia where it is represented by the extant E. grevyi, Grevy's zebra. The occlusal patterns of the lower cheek teeth (P3-M2) of the South African type, and individuals from the Ethiopian Omo Member G and the Egyptian Dakhleh Oasis Holocene pan silts are shown to be sufficiently similar to be considered to be conspecific within a single population.
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Zooarchaeology has the opportunity to expand its analytical horizons into the little explored realm of modern wildlife management by applying the knowledge it gains from its unique perspective of prehistory. Ways in which animal populations threatened with extinction might be protected in perpetuity, identifying which forms or taxa should be reintroduced to which areas to recreate natural biotas, identifying which forms or taxa are exotic and should be removed from an area to create a natural biota, and helping to define the boundaries of biological preserves meant to preserve biota in perpetuity are all subjects to which knowledge gained through zooarchaeological research might be applied. The potential benefits include better informed wildlife management decisions, fewer extinctions, less loss of biological diversity and increased job opportunities for zooarchaeologists.
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Precipitation, primary productivity, and herbivore biomass are linked to ungulate richness (the number of species) in African ecosystems. This study compares the richness of late-middle to late Pleistocene and Holocene ungulate assemblages in southern Africa's Cape Floral Region (CFR). Regression analysis demonstrates that Pleistocene ungulate assemblages are significantly richer than their Holocene counterparts. Elevated Pleistocene ungulate richness is not explained by differential time-averaging, the presence of extinct taxa in Pleistocene assemblages, or by Middle Stone Age (MSA) to Later Stone Age (LSA) technological change, but instead by a greater number of grazing species in Pleistocene faunal communities. Based on modem African analogs, this implies that the Pleistocene assemblages examined here sample time intervals characterized by elevated primary productivity, particularly of grassland habitats, greater ungulate biomass. and altered rainfall regimes. Declining ungulate richness from the Pleistocene to the Holocene supports the hypothesis that the extinction of specialized grazers at the Pleistocene-Holocene transition in the CFR was driven by declining productivity and availability of grassland habitats. The contrast between rich Pleistocene ungulate communities and impoverished Holocene ungulate communities may also explain important differences in MSA and LSA subsistence behavior. It is proposed that intensified exploitation of fish, shellfish, tortoises, and seabirds by LSA foragers during the Holocene reflects an expansion of diet breadth in response to diminished ungulate biomass on the landscape rather than fundamental behavioral/cognitive advances.
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Prologue 1. Morphology, evolutionary history and recent distribution 2. Food and other habitat resources 3. Space-time patterns of habitat use 4. Body size and nutritional physiology 5. Body size and feeding ecology 6. Social organisation and behaviour 7. Life history 8. Body size and sociobiology 9. Body size and reproductive patterns 10. Demography 11. Community interactions 12. Body size and population regulation 13. Body size and ecosystem processes 14. Late Pleistocene extinctions 15. Conservation Epilogue: the megaherbivore syndrome Appendixes References Index.
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Rusingoryx atopocranion is a poorly known extinct alcelaphine bovid, documented in Pleistocene deposits associated with Middle Stone Age artifacts on Rusinga Island, Kenya. Following its initial description, Rusingoryx was subsumed into Megalotragus, which includes the extinct giant wildebeests, on the basis of its cranial architecture. Renewed investigations of the Pleistocene deposits on Rusinga Island recovered a large sample of Rusingoryx specimens that provide new taxonomic and paleoecological insight. This study (1) reviews the morphological and phylogenetic evidence concerning the taxonomic status of Rusingoryx and (2) evaluates its paleoecology and dietary habits. The morphology and phylogenetic data indicate that Rusingoryx is distinct from Megalotragus; they likely shared a common ancestor in the late Pliocene. Ecomorphology and mesowear analysis point to a specialized grazing adaptation, and its association with arid-adapted ungulates suggests a preference for arid grasslands. The confirmation of Rusingoryx as a valid taxonomic entity, together with the presence of other extinct taxa (including Megalotragus) on Rusinga Island, suggests an increasingly complex pattern of ungulate biogeography and extinctions in the late Quaternary of East Africa. Rusingoryx appears to have been part of an arid-adapted faunal community that potentially persisted in East Africa until the onset of the Holocene.
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Paleozoological data reveal past conditions created by anthropogenic and natural processes. These conditions can serve as benchmarks of ecological properties and processes desired by conservation biologists. Paleozoological data provide empirical evidence analogous to experimental results of anthropogenic and environmental causes. They can be used to determine whether a taxon is native or exotic to an area, distinguish invasive from recolonizing taxa, choose a management action likely to produce a desired result, test benchmarks based on historic data, reveal unanticipated effects of conservation efforts, and identify causes of ecological conditions. It is time to use paleoecological knowledge in the service of modern conservation biology.
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Characterizing habitat choice is essential for endangered species conservation. For the endangered Grevy's zebra (Equus grevyi), as with many widely ranging vertebrates, human activities may be an important factor affecting space use. Grevy's zebras are grazing ungulates inhabiting the savannahs of central-northern Kenya and Ethiopia. Past research on their social organization indicates that reproductive status shapes associations and movements. Here, we examine how habitat use varies across four reproductive classes: lactating and nonlactating females, bachelors and territorial males. We also test whether Grevy's zebra avoid locations close to active livestock corrals, or bomas. We find that forage quality, forage quantity and habitat openness of locations used by Grevy's zebra vary significantly depending on individual reproductive state. Lactating females and bachelors use areas with green, short grass and medium-dense bush more frequently than nonlactating females or territorial males. We hypothesize that lactating females trade off forage quantity and safety to access nutrients in growing grass. Across reproductive classes, Grevy's zebra choose locations further from active bomas than if they used the area randomly. Our results suggest that Grevy's zebra may require a range of vegetation characteristics for different reproductive classes. Further, they may need areas free from competition or disturbance by livestock.
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There has been an ongoing controversy over how to decide whether the distribution of species is random — i.e., whether it is not greatly different from what it would be if species did not interact. We recently showed (Roberts and Stone (1990)) that in the case of the Vanuatu (formerly New Hebrides) avifauna, the number of islands shared by species pairs was incompatible with a random null hypothesis. However, it was difficult to determine the causes or direction of the community's exceptionality. In this paper, the latter problem is examined further. We use Diamond's (1975) notion of checkerboard distributions (originally developed as an indicator of competition) and construct a C-score statistic which quantifies checkerboardedness. This statistic is based on the way two species might colonise a pair of islands; whenever each species colonises a different island this adds 1 to the C-score. Following Connor and Simberloff (1979) we generate a control group of random colonisation patterns (matrices), and use the C-score to determine their checkerboard characteristics. As an alternative mode of enquiry, we make slight alterations to the observed data, repeating this process many times so as to obtain another control group. In both cases, when we compare the observed data for the Vanuatu avifauna and the Antillean bat communities with that given by their respective control group, we find that these communities have significantly large checkerboard distributions, making implausible the hypothesis that their species distributions are a product of random colonisation.