Megafaunal extinctions

There are two popular hypotheses to explain extinctions at the end of the last ice age, Climate Change and Overkill (humans hunting herbivores to extinction); each has significant problems. Some have suggested that the two hypotheses in combination would yield a stronger explanation. The Pleistocene Extinction Model (PEM)(Whitney-Smith, 1991, 2003) was originally developed to test a third hypothesis, Second Order

In the previous work, the author wrote in four parts a prediction of a new vector for megafauna extinction, or at least part that no one has discussed for lack of putting stock into Native testimony: the thunderbolts of the gods. In particular the step potential-voltage provided by extremely large thunderbolts. However, despite reliable prediction and simulation by Dr. Anthony Peratt, no perfect 56-rayed crater site with arc-discharge formation had been located. The author made calculations which were verified by Dr. Peratt’s own work. In this work the author presents just such a perfect specimen which, as noted in the aforementioned work, is impossible to be an astrobleme for lack of a bow-shock formation. Furthermore in this work the author presents EMF survey for a nearby located c-henge mound which has the hallmark signs of crater-rim discharge. The EMF survey confirms the hypothesis rather than disproves it, but it opens up other interesting queries, as well. Finally, the author recounts the prediction also made that the Carolina Bays could not possibly be ice impact errata given their various vectors of origin. The news of the Greenland impact has confirmed the author’s predictions, and shown very clearly that the evidence disfavors a single comet impact event to achieve the selective but wide extinction required for the Ice Age Megafauna.

Isotopic tracking of carnivore palaeoecology is a relatively new approach that yielded important results for the study of the non-analogue mammoth steppe biome. After describing the prerequisite to apply this approach and the possible complications, the main achievements will be described for extinct carnivore species such as scimitar-tooth cat Homotherium serum, cave lion Panthera spelaea, giant short-faced bear Arctodus simus, cave bear Ursus spelaeus s.l., as well as for ancient representatives of extant species such as brown bear Ursus arctos and wolf Canis lupus. Isotopic tracking showed that scimitar-tooth cats in Alaska were not a specialist proboscidean predators but rather generalist consumers of other large herbivores. The majority of cave lions analyzed so far were focused on reindeer, some individuals were specialized on cave bears, especially in contexts of competition with cave hyenas. Giant short-faced bears in Alaska were not pure herbivores and consumed meat from reindeer, muskoxen and possibly other predators, but may have still incorporated plant resources in their menu. In contrast, all cave bear populations studied so far for which a clear dietary reconstruction could be done were virtually pure herbivores, only a few cases are still unclear. Interestingly, brown bears used the opposite extreme of the dietary spectrum when competing with other large bears such as cave bears and giant short-faced bears, i.e. were more carnivorous in Europe and more herbivorous in Alaska. Finally wolves seem to have been outcompeted by hyenas but became dominant predators during the Lateglacial in Europe to the expense of the last cave lions. The results obtained through this approach are also relevant for improving conservation strategies of endangered extant large carnivores.

—It will not be extraterrestrial impacts, disease, or other extrinsic agents that will cause the extinction of Man, but rather the collapse of his artificial economy. We argue that there is no productive category of the economy beyond the Service Sector in which to shift the global work force. As the Agriculture, Manufacturing, and Service Sectors continue to shed workers in a bid to reduce costs, this inevitably feeds Unemployment. A global economic regime in which an ever decreasing pool of workers subsidizes an ever growing army of unemployed is axiomatically unsustainable and conduces to system breakdown. That fateful day, profit-minded agricultural corporations will have no further incentive to produce food or deliver it to the cities.

This paper addresses misrepresentations and errors in attacks directed against the Overkill hypothesis that was proposed by Paul Martin to explain selective late Pleistocene extinctions. The opposing Climate-Change hypothesis to explain extinctions is driven by ideology as much as by objective reasoning because it is repeated so frequently without strong new evidence to support it, but it has failed to nail down a victory in public opinion. Overkill, which is not an anti-climate-change hypothesis, is perhaps too ''flexible'' to persuade all scientists, especially because negative evidence (a lack of megafaunal killsites) is considered to be as corroborative as positive evidence. Multiphase models of extinctions that propose different genera died out at different times have become less and less likely as more radiometric dating is done, and overlook the documented variability in atmospheric radiocarbon around the end of the Pleistocene, which prevents the high resolution chronology-building necessary to support a discontinuous model of the extinctions. The extinctions were geologically abrupt, selective, and unique, and therefore they require unique explanations. r

The woolly mammoth (Mammuthus primigenius) was an emblematic and key species of the so-called mammoth steppe ecosystem between ca. 110,000 and 12,000 years ago. Its contribution to human subsistence during the Gravettian period as source of raw material was documented in southwestern France and southwestern Germany, with some evidence of active hunting in the latter region. However, decreasing genetic diversity and increasing indications of nutritional stress point to a likely decline of this megaherbivore. The specificity of the ecological niche occupied by the woolly mammoth is clearly reflected by their collagen 13C and 15N abundances (δ13Ccoll and δ15Ncoll), measured on skeletal remains of the typical mammoth steppe. The abundances of carbon-13 in mammoth collagen are comparable to those of other grazers like horse (Equus sp.), while the nitrogen-15 abundances are significantly higher (about 3‰) than in the other herbivores, either horse or reindeer (Rangifer tarandus). During the Aurignacian and Gravettian occupation at Geißenklösterle in the Ach Valley (Germany), the mammoths had the expected stable isotope signature, but the nitrogen-15 of horses showed an unexpected overlap with those of the mammoth. This unusual pattern was already occurring during the Aurignacian, while the oxygen-18 abundances in bone phosphate (δ18Obp) of horse and reindeer were unchanged between Aurignacian and Gravettian periods, which rules out significant change in environmental and climatic conditions. Thus, we hypothesize that during the Aurignacian and Gravettian, the ecological niche of mammoth was intact but not occupied intensively by mammoths due to a decline in their population. This decline could be tentatively explained by human pressure through hunting. In Dordogne (France), decreasing horse and reindeer δ15Ncoll values coeval to decreasing horse δ18Obp values between the Aurignacian and the Early Gravettian periods reflected a clear change in the environment, while no contrast in δ15Ncoll values was observed between the Early and Final Gravettian at the Abri Pataud. The mammoth of Dordogne yielded slightly higher δ15Ncoll values than expected, probably as a consequence of the nursing effect since all the analyzed samples were ivory instead of bone. The direct dating and sulphur-34 measurement on the ivory of the Early Gravettian at Pataud showed that almost all of them were of contemporaneous and local origin. Significant contrasts in δ34Scoll values were found between the Dordogne and the Ach Valley for the same herbivores species, which confirms the potential of sulphur-34 in collagen as a mobility tracker.

The Gravettian site of Předmostí I in the central Moravian Plain has yielded a rich and diverse large mammal fauna dated around 25-27,000 14C years BP (ca. 29,500–31,500 cal BP). This fauna includes numerous carnivores (cave lion, wolf, brown bear, polar fox, wolverine) and herbivores (reindeer, large bovine, red deer, muskox, horse, woolly rhinoceros, woolly mammoth) whose trophic position could be reconstructed using stable isotopic tracking (δ13C, δ15N, δ34S) of bone collagen (n=63). Among large canids, two morphotypes, “Pleistocene wolves” and “Palaeolithic dogs”, were considered, and two human bones attributed to the Gravettian assemblage of Předmostí I were also sampled. The trophic system around the Gravettian settlement of Předmostí I showed the typical niche partitioning among herbivores and carnivores seen in other mammoth-steppe contexts. The contribution of the analyzed prey species to the diet of the predators, including humans, was evaluated using a Bayesian mixing model (SIAR). Lions included great amounts of reindeer/muskox and possibly bison in their diet, while Pleistocene wolves were more focused on horse and possibly mammoth. Strong reliance on mammoth meat was found for the human of the site, similarly to previously analyzed individuals from other Gravettian sites in Moravia. Interestingly, the large canids interpreted as “Palaeolithic dogs” had a high proportion of reindeer/muskox in their diet, while consumption of mammoth would be expected from the availability of this prey especially in case of close interaction with humans. The peculiar isotopic composition of the Palaeolithic dogs of Předmostí I may indicate some control of their dietary intake by Gravettian people, who could have use them more for transportation than hunting purpose.

Un gran número de especies de megafauna (mamíferos de más de 44 kg de peso) se extinguió en varios continentes entre 50.000 y 10.000 años atrás. Este proceso, tuvo su expresión más debastadora en Amérca, donde el 80% de los grandes mamíferos desapareció a finales del Pleistoceno. Aunque desde hace más de 40 años los científicos debaten sobre los factores que desencadenaron este colapso,y no hay señales de un acuerdo cercano, recientes trabajos en Sudamérica ponen a los seres humanos, su tecnología de caza y sus efectos sobre el ambiente en el centro de la escena

The Snake River Plain may have served as a corridor for the earliest colonists spreading throughout the New World. It has been observed that the distribution of Clovis period sites and raw material used to produce diagnostic points reflects a detailed understanding of the environment. During the Terminal Pleistocene, there is little evidence of Clovis hunter-gatherers interacting with mega-fauna in the Snake River Plain, despite finding both in the same locations but nonassociated. An example of this appears at the Seagull Bay Clovis site (10PR89) where several Clovis projectile points made of locally available obsidian have been found, while adjacent areas have

Numerous Australian caves have produced fossil records that have been critical in piecing together the story of the evolution of the continent's ecosystems through time. Among the most important are those of the Riversleigh World Heritage Area of northeastern Australia. Although the majority of caves in the region have since been destroyed as a result of natural collapses and erosive activities, now-exposed breccias are remarkably abundant in fossils. The fossil faunas include the distant ancestors of the majority of modern Australian vertebrates, as well as extinct lineages such as those of the marsupial 'lions' (Thylacoleonidae) and the diprotodontoids, a group of oversized wombat-like marsupials. Recent radiometric dating in the region, coupled with biochronology, demonstrates that the majority of Riversleigh's fossil assemblages are Miocene in age (ca. 10-18 million years old). Notably, the younger end of the fossil record is poorly represented at Riversleigh, but other cave systems across northeastern Australia provide the necessary temporal extension that can document the emergence of the modern faunas and ecosystems. Karst-dominated regions such as Chillagoe have produced Quaternary-aged (<2.6 million years) fossils, including species found nowhere else on the continent such as Propelopus chillagoensis ('Chillagoe's carnivorous kangaroo'). Chillagoe is also home to the enigmatic extinct land-dwelling crocodile, Quinkana fortirostrum. Recent work in the region has also extended slightly southward to the Broken River karst system. The fossil assemblages in the Broken River caves mostly represent owl-roost accumulations, although deposits thought to be collected by ghost bats and natural pitfall traps have also been recognised. The oldest radiometrically dated fossil deposits are around 350 ka (thousand years old) and include a combination of both extinct and extant faunas. Quaternary geographic range extensions have been recognised for several species including pig-footed bandicoots (Chaeropus spp.), as well as the now-extinct giant short-faced kangaroos (sthenurines), a group previously thought to only occur in southern Australia during the Quaternary. Further to the south, the Mt Etna region provides evidence of significant faunal and ecosystem change through the late Quaternary. Rainforest-adapted vertebrates occur in abundance in cave deposits >280 thousand years old, but give way to more open-adapted faunas by around 200 thousand years ago.

Using a set of high-quality radiocarbon dates, including three new dates from the Hanson site and one from the Folsom component of Hell Gap, we provide a revised estimate of the duration of the Folsom period. Limiting our sample to bone collagen samples pretreated using the XAD resin chromatographic or ultrafiltration techniques, calcined bone, and charcoal from hearth features, we show that Folsom sites fall within a limited range from 12,610 to 12,170 BP, or 440 years. This duration is considerably shorter than previous estimates. Additionally, we show that there is little correlation between the onset and termination of the Younger Dryas and the start and end of the Folsom complex. Finally, the youngest Clovis sites and the last of the Pleistocene megafauna correlate well in time, but are followed by a 100-year gap until the earliest Folsom sites, most likely a result of small sample size.

Around 88 large vertebrate taxa disappeared from Sahul sometime during the Pleistocene, with the majority of losses (54 taxa) clearly taking place within the last 400,000 years. The largest was the 2.8-ton browsing Diprotodon optatum, whereas the ∼100to 130-kg marsupial lion, Thylacoleo carnifex, the world's most specialized mammalian carnivore, and Varanus priscus, the largest lizard known, were formidable predators. Explanations for these extinctions have centered on climatic change or human activities. Here, we review the evidence and arguments for both. Human involvement in the disappearance of some species remains possible but unproven. Mounting evidence points to the loss of most species before the peopling of Sahul (circa 50-45 ka) and a significant role for climate change in the disappearance of the continent's megafauna. megafauna extinction | Pleistocene extinctions | archaeology | human colonization | faunal turnover

In the 1970s, Paul Martin proposed that big game hunters armed with fluted projectile points colonized the Americas and drove the extinction of megafauna. Around fifty years later, the central role of humans ion the extinctions is still strongly debated in North American archaeology, but little considered in South America. Here we analyzes the temporal dynamic and spatial distribution of South American megafauna and fluted (Fishtail) projectile points (Fishtail) to evaluate the role of humans in Pleistocene extinctions. We observe a strong relationship between the temporal density and spatial distribution of the megafaunal species stratigraphically associated with humans  and Fishtail projectile points, as well as with the fluctuations in human demography. On this basis we propose that the direct effect of humans predation was the main factor driving played the central role in the megafaunal decline, with other , probably preying on a few species. The late Pleistocene environmental changes and the indirect effect of human predation probably were co-occurringsecondary, but necessary, co-occurring factors for the collapse of the megafaunal community

ABSTRACT The woolly mammoth (Mammuthus primigenius) was an emblematic and key species of the so-called mammoth steppe ecosystem between ca. 110,000 and 12,000 years ago. Its contribution to human subsistence during the Gravettian period as source of raw material was documented in southwestern France and southwestern Germany, with some evidence of active hunting in the latter region. However, decreasing genetic diversity and increasing indications of nutritional stress point to a likely decline of this megaherbivore. The specificity of the ecological niche occupied by the woolly mammoth is clearly reflected by their collagen 13C and 15N abundances (δ13Ccoll and δ15Ncoll), measured on skeletal remains of the typical mammoth steppe. The abundances of carbon-13 in mammoth collagen are comparable to those of other grazers like horse (Equus sp.), while the nitrogen-15 abundances are significantly higher (about 3‰) than in the other herbivores, either horse or reindeer (Rangifer tarandus). During the Aurignacian and Gravettian occupation at Geißenklösterle in the Ach Valley (Germany), the mammoths had the expected stable isotope signature, but the nitrogen-15 of horses showed an unexpected overlap with those of the mammoth. This unusual pattern was already occurring during the Aurignacian, while the oxygen-18 abundances in bone phosphate (δ18Obp) of horse and reindeer were unchanged between Aurignacian and Gravettian periods, which rules out significant change in environmental and climatic conditions. Thus, we hypothesize that during the Aurignacian and Gravettian, the ecological niche of mammoth was intact but not occupied intensively by mammoths due to a decline in their population. This decline could be tentatively explained by human pressure through hunting. In Dordogne (France), decreasing horse and reindeer δ15Ncoll values coeval to decreasing horse δ18Obp values between the Aurignacian and the Early Gravettian periods reflected a clear change in the environment, while no contrast in δ15Ncoll values was observed between the Early and Final Gravettian at the Abri Pataud. The mammoth of Dordogne yielded slightly higher δ15Ncoll values than expected, probably as a consequence of the nursing effect since all the analyzed samples were ivory instead of bone. The direct dating and sulphur-34 measurement on the ivory of the Early Gravettian at Pataud showed that almost all of them were of contemporaneous and local origin. Significant contrasts in δ34Scoll values were found between the Dordogne and the Ach Valley for the same herbivores species, which confirms the potential of sulphur-34 in collagen as a mobility tracker.

The world's large terrestrial mammalian carnivores and herbivores (henceforth, megafauna) has been severely impacted by humans worldwide. Although this impact across the globe is variable, there has been little information quantifying this impact on biodiversity. Here, we use a macroecological modeling approach to evaluate the impact of different human activities on megafauna species richness at global and biogeographical scales with respect to seven human-altered landscapes variables. At both global and biogeographical scales, we found that human accessibility, human footprint, and small livestock density, had the most negative effects on megafauna species richness, whereas large livestock density, wilderness, and natural protected areas, were more positively associated with megafauna species richness. Our results indicate that megafauna can indeed persist in human-modified landscapes, but different types of human activity can differentially influence species richness. Thus, although continued human impact such as urban, livestock and agricultural development continues to represent a threat to most megafauna, their future viability is potentially compatible with several global change factors we examined. Moreover, our findings are still consistent with the emphasis on conservation strategies that focus on habitat protection to maximize the conservation of megafaunal richness. We urge stronger national and international policy commitments inclusive of multi-use landscapes, greater anti-poaching enforcement, and the development of wildlife-friendly policy incentives for the managers of private and communal land. We also advise caution in interpreting our results, and believe local and regional scale population monitoring programs are still necessary to better facilitate coexistence with humans.

The reasons for megafaunal extinction in Australia have been hotly debated for over 30 years without any clear resolution. The proposed causes include human overkill, climate, anthropogenic induced habitat change or a combination of these. Most protagonists of the human overkill model suggest the impact was so swift, occurring within a few thousand years of human occupation of the continent, that archaeological evidence should be rare or non-existent. In Tasmania the presence of extinct megafauna has been known since the early twentieth century with earlier claims of human overlap being rejected because of poor chronology and equivocal stratigraphic associations. More recent archaeological research has not identified any megafauna from the earliest, exceptionally well-preserved late Pleistocene cultural sites. In 2008 however an argument for human induced megafaunal extinctions was proposed using the direct dates from a small sample of surface bone from two Tasmanian nonhuman caves and a museum sediment sample from an unknown location in a cave, since destroyed by quarrying . supplemented their data with published dates from other Tasmanian caves and open sites to argue for the survival of at least seven megafauna species from the last interglacial to the subsequent glacial stage.

This article investigates how in the Soviet Arctic researchers and indigenous communities searched and understood the mammoth before and during the Cold War. Based on a vast number of published and unpublished sources as well as interviews with scholars and reindeer herders, this article demonstrates that the mammoth, as a paleontological find fusing together features of extinct and extant species, plays an in-between role among various environmental epistemologies. The author refers to moments of interactions among these different actors as “environmental encounters”, which comprise and engage with the physical, political, social and cultural environments of the Arctic. These encounters shape the temporal stabilisations of knowledge which enable the mammoth to live its post-extinct life. This article combines approaches from environmental history and anthropology, history of science and indigenous studies showing the social vitality of a “fossil object”.

The ability of sedimentary proxies (especially dung fungal spores) to reflect the past presence and density of large herbivores on a landscape has been receiving increasing scrutiny. Here we examine the Sporormiella spore record from a well-dated, multi-proxy, highly organic sedimentary record from the small lake basin of Marcacocha in the Cuzco region of Peru. The basin, a wetland since ca. AD 1840, existed as a small lake for at least 4000 years prior. Previous work at Marcacocha has shown that changes in herbivore densities reflect the abundances of oribatid mites preserved in the lake sediments. This study tests the assumption that both the Sporormiella and the oribatid mite records responded in broadly the same way to changes in herbivore densities over the past 1200 years.
Analysis reveals a very low covariance between concentrations of Sporormiella spores and the two major components of the oribatid mite assemblage: a single aquatic species of Hydrozetes and a less abundant, wider grouping comprising members of the mostly terrestrial superfamily Ceratozetoidea (referred to as the ‘ceratozetoids’). Variations in the Hydrozetes assemblage clearly dovetail with known historical events, including the massive decline of indigenous and camelid populations following the collapse of the Inca Empire in the mid-sixteenth century. Comparison with other environmental proxies from the Marcacocha sequence, including diatoms and charophyte oospores, suggests that the ceratozetoids appear to reflect increasing terrestrialization. In contrast, although the Sporormiella record indicates the presence of livestock, it fails to register the major historical changes in herbivore presence, though reflects well episodes of lake-level lowering. In small lake settings, therefore, the use of Sporormiella to estimate the density of herbivores in the catchment might be considered a relatively blunt instrument when compared with some other indicators.

The extinction of the Pleistocene megafauna (Pleistocene-age mammals exceeding 45 kilograms adult body mass) of North America has been hotly debated for much of the last century. Hypothesized extinction causes include overhunting, climate change, and other fringe hypotheses (e.g., comet impact, disease, or solar activity). Roughly half of all extinct genera in North America lived alongside humans, according to some researchers (e.g., Grayson and Meltzer 2015). Of those contemporaneous genera, there is direct evidence of hunting by humans of only a few taxa (especially mammoths, mastodons, gomphotheres, bison, camels, and horses). This study reviews previously published data on megafauna fossils in Oklahoma. This is a review of which megafauna taxa were present in Oklahoma and when during the Pleistocene they were last seen in the local fossil record. Only a few megafauna taxa (mainly mammoths and bison) in Oklahoma coexisted with humans, while many other taxa (ground sloths, musk oxen, etc.) were no longer present. The fossil evidence suggests that the Pleistocene extinction was more environmental in nature, and that humans were not the sole cause (at least in Oklahoma).

In an effort to evaluate the validity of the most often discussed mammalian extinction models, sixteen site areas in northwest Oregon were examined. These are predominately archaeological and/or paleontological sites, although several locations yielded only geomorphological information. Through the inspection of sites occurring at vastly different elevations, and depicting numerous past environments, a broad view of the late Pleistocene for the area is well represented. A human presence, associated with many of the faunal bearing strata, was also identified. This paper examines the findings of this multidisciplinary investigation, and how they validate or invalidate each model of causality for late Pleistocene mammalian extinctions. Importantly, during this study an additional probable extinction element was identified. It, too, is considered.

the late Quaternary megafauna extinctions reshaped species assemblages, yet we know little about how extant obligate scavengers responded to this abrupt ecological change. to explore whether obligate scavengers persisted by depending on contemporary community linkages or via foraging flexibility, we tested the importance of the trophic interaction between pumas (Puma concolor) and native camelids (Vicugna vicugna and Lama guanicoe) for the persistence of Andean condors (Vultur gryphus) in southern south America, and compared the demographic history of three vultures in different continents. We sequenced and compiled mtDNA to reconstruct past population dynamics. Our results suggest that Andean condors increased in population size >10 KYA, whereas vicuñas and pumas showed stable populations and guanacos a recent (<10 KYA) demographic expansion, suggesting independent trajectories between species. Further, vultures showed positive demographic trends: white-backed vultures (Gyps africanus) increased in population size, matching attenuated community changes in Africa, and California condors (Gymnogyps californianus) exhibited a steep demographic expansion ~20 KYA largely concurrent with North American megafaunal extinctions. Our results suggest that dietary plasticity of extant vulture lineages allowed them to thrive despite historical environmental changes. This dietary flexibility, however, is now detrimental as it enhances risk to toxicological compounds harbored by modern carrion resources. Historical species assemblages can provide insight into the contemporary structure and functioning of communities 1. Pleistocene communities, in particular, sustained diverse vertebrate assemblages of mega-carnivores and-herbivores (average body size ≥44 kg) 2,3 that provided plentiful carrion resources for scavenging 4. These carrion resources precipitated a rapid radiation of avian obligate scavengers 5-7 that varied in morphology and body size according to different feeding strategies 8. Climatic changes and human impacts during the Pleistocene-Holocene transition triggered a massive loss of megafauna 9-11 : only ~5% of megaherbivores, 40% of megacarnivores 12 , and ~41% of obligate scavengers 7,13 genera persisted. The near-complete disassembly of Pleistocene communities radically transformed ecological interactions for those species that went through the extinction epoch 1. Yet, the mechanisms by which species survived ecological changes are poorly understood, especially for guilds tightly linked to mega-mammals. The Pleistocene megafaunal extinctions were a globally heterogeneous phenomenon 12,14. Across Africa and southeast Eurasia, where large-bodied species had a deep history of coevolution with hominids, loss of megafauna was relatively moderate and gradual 15. For example, in Sub-Saharan Africa most of the Pleistocene megafauna persist today, including 31 genera of mega-herbivores and 5 mega-carnivores 12. Unsurprisingly, then, Africa (n = 11) and southern Asia (n = 10) support the greatest diversity of the largest obligate scavengers 16 which rely upon carrion from herds of ungulates that die primarily from non-predatory causes 17,18. In contrast, the mega-fauna of the Americas experienced a punctuated wave of extinctions, losing 70-80% of Pleistocene megafauna genera 12,19 from a combination of climate changes and human arrival 9,10,20. In North America, this extinction wave drove the disappearance of at least seven genera of vultures 21,22. The California condor (Gymnogyps californianus), however, persisted into the Holocene by relying on marine-derived food resources 23,24. The megafauna extinctions in South America were more extensive than on any other continent with the complete loss of mega-herbivores, 50% of megacarnivores 12,25 , and at least 50% of vultures 26-28. Notably, however, a

This paper addresses misrepresentations and errors in attacks directed against the Overkill hypothesis that was proposed by Paul Martin to explain selective late Pleistocene extinctions. The opposing Climate-Change hypothesis to explain extinctions is driven by ideology as much as by objective reasoning because it is repeated so frequently without strong new evidence to support it, but it has failed to nail down a victory in public opinion. Overkill, which is not an anti-climate-change hypothesis, is perhaps too ''flexible'' to persuade all scientists, especially because negative evidence (a lack of megafaunal killsites) is considered to be as corroborative as positive evidence. Multiphase models of extinctions that propose different genera died out at different times have become less and less likely as more radiometric dating is done, and overlook the documented variability in atmospheric radiocarbon around the end of the Pleistocene, which prevents the high resolution chronology-building necessary to support a discontinuous model of the extinctions. The extinctions were geologically abrupt, selective, and unique, and therefore they require unique explanations.

U radu je analiziran biljni i životinjski svijet u vrijeme paleolita u sjevernoj Bosni. U vrijeme trajanja paleolita, klimatske smjene hladnih i toplijih perioda, potpuno su uništile ili barem bitno izmjenile sastav biljnog i životinjskog svijeta koji mu je prethodio. U radu su navedene najznačajnije biljne i životinjske vrste koje su živile u određenom vremenu paleolita, u sjevernoj Bosni, čije je postojanje dokazano pronalaskom fosilnih dokaza (polena, listova, grana, kostiju i sl.).

Understanding megafaunal population dynamics is critical to testing and refining scenarios of how extinctions occurred during the terminal Pleistocene. Large-scale, collections-based, chronological, and taphonomic analyses of midwestern Proboscidea suggest divergent population histories in mammoths and mastodons after the Last Glacial Maximum (LGM). Although extinction of both taxa occurred in the very late Bølling-Allerød (B-A) or early Younger Dryas (YD), Mammuthus is dominant during the LGM with a decreasing presence in the region until extirpation. Mammut americanum however, is absent during the LGM but becomes the dominant taxon during the subsequent B-A. Trace and physical evidence of large carnivores in post-LGM proboscidean assemblages is extremely rare, suggesting apex predators had minimal impact on mammoth and mastodon populations at this time. The ultimate mechanism(s) of extinction remain unclear; however, the wide geographic distribution of late Mammut and an increase in the frequency of multi-animal death assemblages is consistent with a large, destabilized population experiencing periodic boom-bust cycling at the end of the B-A. We suggest this pattern is due to the collapse of trophic controls on proboscidean populations prior to the LGM and a subsequent system-wide shift from top-down to bottom-up regulatory mechanisms in Proboscidea.

The ability of sedimentary proxies (especially dung fungal spores) to reflect the past presence and density of large herbivores on a landscape has been receiving increasing scrutiny. Here we examine the Sporormiella spore record from a well-dated, multiproxy, highly organic sedimentary record from the small lake basin of Marcacocha in the Cuzco region of Peru. The basin, a wetland since ca. AD 1840, existed as a small lake for at least 4000 years prior. Previous work at Marcacocha has shown that changes in herbivore densities reflect the abundances of oribatid mites preserved in the lake sediments. This study tests the assumption that both the Sporormiella and the oribatid mite records responded in broadly the same way to changes in herbivore densities over the past 1200 years. Analysis reveals a very low covariance between concentrations of Sporormiella spores and the two major components of the oribatid mite assemblage: a single aquatic species of Hydrozetes and a less abundant, wider grouping comprising members of the mostly terrestrial superfamily Ceratozetoidea (referred to as the 'ceratozetoids'). Variations in the Hydrozetes assemblage clearly dovetail with known historical events, including the massive decline of indigenous and camelid populations following the collapse of the Inca Empire in the mid-sixteenth century. Comparison with other environmental proxies from the Marcacocha sequence, including diatoms and charophyte oospores, suggests that the ceratozetoids appear to reflect increasing terrestrialization. In contrast, although the Sporormiella record indicates the presence of livestock, it fails to register the major historical changes in herbivore presence, though reflects well episodes of lake-level lowering. In small lake settings, therefore, the use of Sporormiella to estimate the density of herbivores in the catchment might be considered a relatively blunt instrument when compared with some other indicators. Supporting Information: Appendix S1 Comparison of Sporormiella dung fungal spores and oribatid mites as indicators of large herbivore presence: evidence from the Cuzco region of Peru

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Significance We provide global assessment of the possible link between Pleistocene hominin arrival and island extinction. The existing records on islands around the world do not support a significant and detrimental impact on island biotas following island colonization prior to the Holocene. This suggests that models using island extinctions as evidence in support of anthropogenic megafaunal overhunting, or as extensions of continental-level extinctions, need to be reconsidered.

the late Quaternary megafauna extinctions reshaped species assemblages, yet we know little about how extant obligate scavengers responded to this abrupt ecological change. to explore whether obligate scavengers persisted by depending on contemporary community linkages or via foraging flexibility, we tested the importance of the trophic interaction between pumas (Puma concolor) and native camelids (Vicugna vicugna and Lama guanicoe) for the persistence of Andean condors (Vultur gryphus) in southern south America, and compared the demographic history of three vultures in different continents. We sequenced and compiled mtDNA to reconstruct past population dynamics. Our results suggest that Andean condors increased in population size >10 KYA, whereas vicuñas and pumas showed stable populations and guanacos a recent (<10 KYA) demographic expansion, suggesting independent trajectories between species. Further, vultures showed positive demographic trends: white-backed vultures (Gyps africanus) increased in population size, matching attenuated community changes in Africa, and California condors (Gymnogyps californianus) exhibited a steep demographic expansion ~20 KYA largely concurrent with North American megafaunal extinctions. Our results suggest that dietary plasticity of extant vulture lineages allowed them to thrive despite historical environmental changes. This dietary flexibility, however, is now detrimental as it enhances risk to toxicological compounds harbored by modern carrion resources.

The two living species of bison (European and American) are among the few terrestrial megafauna to have survived the late Pleistocene extinctions. Despite the extensive bovid fossil record in Eurasia, the evolutionary history of the European bison (or wisent, Bison bonasus) before the Holocene (o11.7 thousand years ago (kya)) remains a mystery. We use complete ancient mitochondrial genomes and genome-wide nuclear DNA surveys to reveal that the wisent is the product of hybridization between the extinct steppe bison (Bison priscus) and ancestors of modern cattle (aurochs, Bos primigenius) before 120 kya, and contains up to 10% aurochs genomic ancestry. Although undetected within the fossil record, ancestors of the wisent have alternated ecological dominance with steppe bison in association with major environmental shifts since at least 55 kya. Early cave artists recorded distinct morphological forms consistent with these replacement events, around the Last Glacial Maximum (LGM, B21–18...

the cave bear (Ursus spelaeus) is one of the Late pleistocene megafauna species that faced extinction at the end of the last ice age. Although it is represented by one of the largest fossil records in Europe and has been subject to several interdisciplinary studies including palaeogenetic research, its fate remains highly controversial. Here, we used a combination of hybridisation capture and next generation sequencing to reconstruct 59 new complete cave bear mitochondrial genomes (mtDNA) from 14 sites in Western, Central and Eastern Europe. In a Bayesian phylogenetic analysis, we compared them to 64 published cave bear mtDNA sequences to reconstruct the population dynamics and phylogeography during the Late Pleistocene. We found five major mitochondrial DNA lineages resulting in a noticeably more complex biogeography of the European lineages during the last 50,000 years than previously assumed. Furthermore, our calculated effective female population sizes suggest a drastic cave bear population decline starting around 40,000 years ago at the onset of the Aurignacian, coinciding with the spread of anatomically modern humans in Europe. Thus, our study supports a potential significant human role in the general extinction and local extirpation of the european cave bear and illuminates the fate of this megafauna species.

Genetic data suggest that the Native American founder population diverged from its Asian parent
population about 25,000 years ago and was geographically isolated during the Last Glacial Maximum
(LGM, ca. 21,000 years BP) before dispersing into North and South America as the ice sheets retreated.
Archaeological evidence in eastern Siberia and Beringia is scarce, however. Although stone tools and
cutmarks on bones dated to the LGM are reported at Bluefish Caves (Yukon Territory, Canada), the
stratigraphic integrity of the site and the interpretation of the bone modifications have long been
questioned by the scientific community. Here, we describe the results of a zooarchaeological study of the
faunal assemblages from Pleistocene loess deposits of Bluefish Caves 1 and 2. Taphonomic analyses
indicate that humans hunted a variety of prey at the site, including the Beringian horse (E. lambei), as
early as 23,500 years BP. We discuss the significance of the site in debates about the timing of the initial
peopling of North America and the role of human-hunters in megafaunal extinctions.