scholarly journals Dendrochronological dates confirm a Late Prehistoric population decline in the American Southwest derived from radiocarbon dates

2020 ◽  
Author(s):  
Erick Robinson ◽  
R. Kyle Bocinsky ◽  
Darcy Bird ◽  
Jacob Freeman ◽  
Robert L. Kelly
Keyword(s):  
Time Series ◽  
Population Decline ◽  
American Southwest ◽  
Human Populations ◽  
Late Prehistoric ◽  
Population Declines ◽  
Sample Collection ◽  
Radiocarbon Dates ◽  
Anal Ysis ◽  
Radiocarbon Data

The northern American Southwest provides one of the most well-documented cases of human population growth and decline in the world. The geographic extent of this decline in North Amer- ica is unknown due to the lack of high-resolution palaeodemographic data from regions across and beyond the greater Southwest, where archaeological radiocarbon data is often the only avail- able proxy for investigating these palaeodemographic processes. Radiocarbon time series across and beyond the greater Southwest suggest widespread population collapses from AD 1300–1600. However, radiocarbon data have potential biases caused by variable radiocarbon sample preser- vation, sample collection, and the non-linearity of the radiocarbon calibration curve. In order to be confident in the wider trends seen in radiocarbon time series across and beyond the greater Southwest, here we focus on regions that have multiple palaeodemographic proxies and com- pare those proxies to radiocarbon time series. We develop a new method for time series anal- ysis and comparison between dendrochronological data and radiocarbon data. Results confirm a multiple proxy decline in human populations across the Upland US Southwest, Central Mesa Verde, and Northern Rio Grande from AD 1300–1600. These results lend confidence to single proxy radiocarbon-based reconstructions of paleodemography outside the Southwest that sug- gest post-AD 1300 population declines in many parts of North America.

scholarly journals Dendrochronological dates confirm a Late Prehistoric population decline in the American Southwest derived from radiocarbon dates

2020 ◽  
Vol 376 (1816) ◽  
pp. 20190718 ◽  
Author(s):  
Erick Robinson ◽  
R. Kyle Bocinsky ◽  
Darcy Bird ◽  
Jacob Freeman ◽  
Robert L. Kelly
Keyword(s):  
Time Series ◽  
North America ◽  
Population Decline ◽  
American Southwest ◽  
Human Populations ◽  
Late Prehistoric ◽  
Population Declines ◽  
Sample Collection ◽  
Radiocarbon Dates ◽  
Radiocarbon Data

The northern American Southwest provides one of the most well-documented cases of human population growth and decline in the world. The geographic extent of this decline in North America is unknown owing to the lack of high-resolution palaeodemographic data from regions across and beyond the greater Southwest, where archaeological radiocarbon data are often the only available proxy for investigating these palaeodemographic processes. Radiocarbon time series across and beyond the greater Southwest suggest widespread population collapses from AD 1300 to 1600. However, radiocarbon data have potential biases caused by variable radiocarbon sample preservation, sample collection and the nonlinearity of the radiocarbon calibration curve. In order to be confident in the wider trends seen in radiocarbon time series across and beyond the greater Southwest, here we focus on regions that have multiple palaeodemographic proxies and compare those proxies to radiocarbon time series. We develop a new method for time series analysis and comparison between dendrochronological data and radiocarbon data. Results confirm a multiple proxy decline in human populations across the Upland US Southwest, Central Mesa Verde and Northern Rio Grande from AD 1300 to 1600. These results lend confidence to single proxy radiocarbon-based reconstructions of palaeodemography outside the Southwest that suggest post-AD 1300 population declines in many parts of North America. This article is part of the theme issue ‘Cross-disciplinary approaches to prehistoric demography’.

scholarly journals Widespread population decline in South America correlates with mid-Holocene climate change

2018 ◽  
Author(s):  
Philip Riris ◽  
Manuel Arroyo-Kalin
Keyword(s):  
Climate Change ◽  
South America ◽  
Large Scale ◽  
Climatic Variability ◽  
Population Decline ◽  
Plant Management ◽  
Human Populations ◽  
Resource Base ◽  
Radiocarbon Dates ◽  
Middle Holocene

Quantifying the impacts of climate change on prehistoric demography is crucial for understanding the adaptive pathways taken by human populations. Archaeologists across South America have pointed to patterns of regional abandonment during the Middle Holocene (8200 to 4200 cal BP) as evidence of sensitivity to shifts in hydroclimate over this period. We develop a unified approach to investigate demography and climate in South America and aim to clarify the extent to which evidence of local anthropic responses can be generalised to large-scale trends. We achieve this by integrating archaeological radiocarbon data and palaeoclimatic time series to show that population decline occurred coeval with the transition to the initial mid-Holocene across South America. Through the analysis of radiocarbon dates with Monte Carlo methods, we find multiple, sustained phases of downturn associated to periods of high climatic variability. A likely driver of the duration and severity of demographic turnover is the frequency of exceptional climatic events, rather than the absolute magnitude of change. Unpredictable levels of tropical precipitation had sustained negative impacts on pre-Columbian populations lasting until at least 6000 cal BP, after which recovery is evident. Our results support the inference that a demographic regime shift in the second half of the Middle Holocene were coeval with cultural practices surrounding Neotropical plant management and early cultivation, possibly acting as buffers when the wild resource base was in flux.

Palaeolithic Big Game Hunting at HP766 in Wadi Umm Rahau, Northern Sudan

2012 ◽  
Vol 10 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Achilles Gautier ◽  
Daniel Makowiecki ◽  
Henryk Paner ◽  
Wim Van Neer
Keyword(s):  
Late Prehistoric ◽  
Large Mammals ◽  
Radiocarbon Dates ◽  
Large Size ◽  
Animal Bone ◽  
Game Hunting ◽  
Big Game Hunting ◽  
Bone Remains

HP766, discovered by the Gdansk Archaeological Museum Expedition (GAME) in the region immediately upstream the Merowe Dam in North Sudan and now under water, is one of the few palaeolithic sites with animal bone remains in the country. The archaeological deposits, the large size of the site, the lithics and the radiocarbon dates indicate occupation of a silt terrace of the Nile in late MSA and perhaps LSA times. Large and very large mammals predominate markedly among the recovered bone remains and it would seem that the palaeolithic hunters focused on such game. They could corner these animals on the site which is partially surrounded by high bedrock outcrops. Moreover swampy conditions of the site after the retreat of the annual Nile flood may have rendered less mobile the prey animals. According to this scenario, HP766 would testify to the ecological skills and generational memory of late prehistoric man in Sudan.

scholarly journals Radiocarbon Chronology of Late Neolithic Settlements in the Tisza-Maros Region, Hungary

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 859-866 ◽  
Author(s):  
Ede Hertelendi ◽  
Ferenc Horváth
Keyword(s):  
Late Neolithic ◽  
Unique Type ◽  
Radiocarbon Dates ◽  
Radiocarbon Data ◽  
Stratigraphic Position ◽  
European Neolithic ◽  
Radiocarbon Chronology ◽  
Developmental Phases

We investigated chronological questions of five Late Neolithic settlements in the Hungarian Tisza-Maros region. Fifty new radiocarbon dates provide an internal chronology for the developmental phases of the tell settlements, and place them into the wider framework of the southeastern European Neolithic. An example is presented of how a unique type of stratigraphic excavation helps the interpretation of radiocarbon data, which are in contradiction with the stratigraphic position of the samples.

scholarly journals Patterns of smallpox mortality in London, England, over three centuries

PLoS Biology ◽  
2020 ◽  
Vol 18 (12) ◽  
pp. e3000506
Author(s):  
Olga Krylova ◽  
David J. D. Earn
Keyword(s):  
Public Health ◽  
Infectious Disease ◽  
Time Series ◽  
Spectral Analysis ◽  
Infectious Diseases ◽  
Health Policies ◽  
Human Populations ◽  
Public Health Policies ◽  
History Of ◽  
History Of Control

Smallpox is unique among infectious diseases in the degree to which it devastated human populations, its long history of control interventions, and the fact that it has been successfully eradicated. Mortality from smallpox in London, England was carefully documented, weekly, for nearly 300 years, providing a rare and valuable source for the study of ecology and evolution of infectious disease. We describe and analyze smallpox mortality in London from 1664 to 1930. We digitized the weekly records published in the London Bills of Mortality (LBoM) and the Registrar General’s Weekly Returns (RGWRs). We annotated the resulting time series with a sequence of historical events that might have influenced smallpox dynamics in London. We present a spectral analysis that reveals how periodicities in reported smallpox mortality changed over decades and centuries; many of these changes in epidemic patterns are correlated with changes in control interventions and public health policies. We also examine how the seasonality of reported smallpox mortality changed from the 17th to 20th centuries in London.

Conservation biology of marine fishes: perceptions and caveats regarding assignment of extinction risk

2001 ◽  
Vol 58 (1) ◽  
pp. 108-121 ◽  
Author(s):  
Jeffrey A Hutchings
Keyword(s):  
Population Size ◽  
Extinction Risk ◽  
Population Decline ◽  
Empirical Support ◽  
Marine Fishes ◽  
Marine Biodiversity ◽  
Population Declines ◽  
High Fecundity ◽  
Reproductive Rates ◽  
Biological Extinction

Quantitative criteria used to assign species to categories of extinction risk may seriously overestimate these risks for marine fishes. Contemporary perception is that marine fishes may be less vulnerable to extinction than other taxa, because of great natural variability in abundance, high fecundity, rapid population growth, and an intrinsically high capability of recovering from low population size. Contrary to perception, however, there appears to be generally little theoretical or empirical support for the hypotheses that marine fish are more likely to experience large reductions in population size, to produce unusually high levels of recruitment, to have higher reproductive rates, or to recover more rapidly from prolonged population declines than nonmarine fishes. Although existing population-decline criteria may not accurately reflect probabilities of biological extinction, they do appear to reflect the converse-population recovery. Insufficient support for contemporary perceptions of their susceptibility to extinction, coupled with caveats associated with the assignment of extinction risk, suggest that significant increases in the population-decline thresholds used to assign marine fishes to at-risk categories would be inconsistent with a precautionary approach to fisheries management and the conservation of marine biodiversity.

scholarly journals Australian corticolous myxomycetes: models of distribution and development

2019 ◽  
Vol 67 (8) ◽  
pp. 617 ◽  
Author(s):  
Peter Wellman
Keyword(s):  
Population Decline ◽  
Common Species ◽  
Growth Cycle ◽  
Population Increase ◽  
Arid Areas ◽  
Species Assemblage ◽  
Population Declines ◽  
Moist Chamber ◽  
Linear Plot ◽  
Chamber Technique

This paper presents an integrated model of the variation over a continental landmass of myxomycetes, a single-celled organism in the phylum Amoebozoa. Bark samples were collected on long traverses across Australia, and cultivated in Petri dishes by the moist chamber technique to obtain large assemblages of common species. The results of this survey and previous surveys are consistent with there being four major myxomycete assemblages: Tropical, Northern Arid, Southern Arid and Temperate. Where mapped, these species assemblage regions are consistent with the Australian phytogeographical regions. The myxomycetes differ between arid and non-arid areas; the arid areas have slightly higher productivity per wetting event, with members of the Physarales and Liceales relatively important and the Stemonitidales, Trichiales and Cribrariales less important. When the bark samples are placed in a moist culture there is a myxomycete growth cycle and then the population declines to resting phases. The population increase during a growth phase can be modelled by a linear plot of log(abundance) against species rank, where abundance is total harvested spore volume of a species. The population decline appears to be linear from two weeks after watering, declining to negligible activity 4 weeks after watering.

Fates and movements of meadow voles (Microtus pennsylvanicus) following a population decline

1988 ◽  
Vol 66 (2) ◽  
pp. 323-328 ◽  
Author(s):  
Steve Mihok ◽  
Todd Lawton ◽  
Bill Schwartz
Keyword(s):  
Direct Evidence ◽  
Population Decline ◽  
Microtus Pennsylvanicus ◽  
Population Declines ◽  
Severe Winter ◽  
Meadow Voles ◽  
Small Areas ◽  
Small Mustelids ◽  
Winter Population

The movements of 24 meadow voles were monitored with radiotelemetry during summer 1985 near Pinawa, Manitoba, to ascertain fates following a severe winter population decline. Low breeding season survival of 22% per month resulted in the persistence of low numbers through spring 1986. Despite densities of only a few individuals per hectare, voles were captured in both meadows and forests. Some voles first caught in forests (mostly males) moved over large areas (up to 4 ha), including both meadow and forest habitat. In contrast, voles captured in meadows were sedentary, often confining their movements to small areas of 0.1–0.2 ha. Radiotransmitters were recovered from 18 of 19 voles that died during the study. Five voles (28%) appeared to have died in situ; six voles (33%) may have been taken by an unusually clean predator or scavenger. Fates of the remaining voles were uncertain. No direct evidence of predation by small mustelids was found to support the hypothesis that these predators account for the persistence of low density following population declines.

scholarly journals A globally threatened shark, Carcharias taurus, shows no population decline in South Africa

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Juliana D. Klein ◽  
Aletta E. Bester-van der Merwe ◽  
Matthew L. Dicken ◽  
Arsalan Emami-Khoyi ◽  
Kolobe L. Mmonwa ◽  
...  
Keyword(s):  
South Africa ◽  
Census Data ◽  
Demographic History ◽  
Conservation Status ◽  
Population Decline ◽  
Multilocus Genotype ◽  
Population Declines ◽  
Effective Population ◽  
Anthropogenic Pressures ◽  
Carcharias Taurus

Abstract Knowledge about the demographic histories of natural populations helps to evaluate their conservation status, and potential impacts of natural and anthropogenic pressures. In particular, estimates of effective population size obtained through molecular data can provide useful information to guide management decisions for vulnerable populations. The spotted ragged-tooth shark, Carcharias taurus (also known as the sandtiger or grey nurse shark), is widely distributed in warm-temperate and subtropical waters, but has suffered severe population declines across much of its range as a result of overexploitation. Here, we used multilocus genotype data to investigate the demographic history of the South African C. taurus population. Using approximate Bayesian computation and likelihood-based importance sampling, we found that the population underwent a historical range expansion that may have been linked to climatic changes during the late Pleistocene. There was no evidence for a recent anthropogenic decline. Together with census data suggesting a stable population, these results support the idea that fishing pressure and other threats have so far not been detrimental to the local C. taurus population. The results reported here indicate that South Africa could possibly harbour the last remaining, relatively pristine population of this widespread but vulnerable top predator.

Evaluating the Old Wood Problem in a Temperate Climate: A Fort Ancient Case Study

2014 ◽  
Vol 79 (04) ◽  
pp. 763-775 ◽  
Author(s):  
Robert A. Cook ◽  
Aaron R. Comstock
Keyword(s):  
North America ◽  
American Southwest ◽  
Wood Charcoal ◽  
Arid Climate ◽  
Temperate Climate ◽  
Radiocarbon Dates ◽  
Eastern Woodlands ◽  
Fort Ancient

Abstract Schiffer (1986) first identified the old wood problem for wood charcoal-based dates from archaeological contexts in the American Southwest. The potential for dates to be skewed toward excessively old calendar ages in this region has recently generated reticence in part of the archaeological community towards including wood charcoal dates in general. Some scholars have even begun to cleanse the radiocarbon databases of regions throughout North America, partly with this presumed limitation in mind. However, the issues that contribute to the old wood problem have not been closely examined outside the arid climate of the American Southwest, resulting in some studies excluding hundreds of radiocarbon dates. The present study fills that void by examining the radiocarbon record from four well-dated Fort Ancient sites in southwestern Ohio and southeastern Indiana. Specifically, we test whether or not there are significant differences between wood charcoal and non-wood charcoal assays. Our findings suggest that wood charcoal dates should not be excluded. We explore reasons for this difference in the Eastern Woodlands and propose an ideal dating regime.

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