scholarly journals Neolithic population crash in northwest Europe associated with agricultural crisis

2019 ◽  
Vol 92 (3) ◽  
pp. 686-707 ◽  
Author(s):  
Sue Colledge ◽  
James Conolly ◽  
Enrico Crema ◽  
Stephen Shennan
Keyword(s):  
Cultural Evolution ◽  
Population Decline ◽  
Agricultural Productivity ◽  
Climatic Conditions ◽  
Population Densities ◽  
Population Crash ◽  
Northwest Europe ◽  
Cereal Production ◽  
Boom And Bust ◽  
Neolithic Europe

AbstractThe focus of this paper is the Neolithic of northwest Europe, where a rapid growth in population between ~5950 and ~5550 cal yr BP is followed by a decline that lasted until ~4950 cal yr BP. The timing of the increase in population density correlates with the local appearance of farming and is attributed to the advantageous effects of agriculture. However, the subsequent population decline has yet to be satisfactorily explained. One possible explanation is the reduction in yields in Neolithic cereal-based agriculture due to worsening climatic conditions. The suggestion of a correlation between Neolithic climate deterioration, agricultural productivity, and a decrease in population requires testing for northwestern Europe. Data for our analyses were collected during the Cultural Evolution of Neolithic Europe project. We assess the correlation between agricultural productivity and population densities in the Neolithic of northwest Europe by examining the changing frequencies of crop and weed taxa before, during and after the population “boom and bust.” We show that the period of population decline is coincidental with a decrease in cereal production linked to a shift towards less fertile soils.

scholarly journals Population fluctuations and breeding of eland Taurotragus oryx in a western Transvaal nature reserve

Koedoe ◽  
1991 ◽  
Vol 34 (1) ◽  
Author(s):  
D. Buys ◽  
H.M. Dott
Keyword(s):  
Nature Reserve ◽  
Climatic Conditions ◽  
Population Fluctuations ◽  
Founder Population ◽  
Population Crash ◽  
History Of ◽  
Calf Mortality ◽  
Calving Rate ◽  
Heavy Rains

The history of an eland population on the S A Lombard Nature Reserve in the western Transvaal is described. From a founder population of four eland in 1950 and 1951, the population grew to about 35 animals and was kept at this level through culling and translocation until 1976. During 1976 and 1977 unusual heavy rains were experienced and culling and removals were temporarily suspended. As a result the population increased unchecked and reached a peak of 81 in 1981. When climatic conditions returned to normal this was followed by a population crash in which 66 eland died over a period of three years. Calves are born throughout the year, but the majority of births occur during the period October to December, with a peak in November. The females have a high calving rate (90,9 ) and calf mortality is low (16,7 ).

Human-provoked amphibian decline in central Italy and the efficacy of protected areas

2010 ◽  
Vol 37 (7) ◽  
pp. 547 ◽  
Author(s):  
Manuela D'Amen ◽  
Biancamaria Pietrangeli ◽  
Marco A. Bologna
Keyword(s):  
Protected Areas ◽  
Multiple Stressors ◽  
Population Decline ◽  
Central Italy ◽  
Negative Relationship ◽  
Climatic Conditions ◽  
Amphibian Declines ◽  
Additive Models ◽  
Management Approach ◽  
Amphibian Species

Context Today, more than 32% of amphibian species are threatened and more than 43% face a steep decline in numbers. Most species are being affected simultaneously by multiple stressors and habitat protection is often inadequate to prevent declines. Aims The main goal of the present research was to understand the consequences of alternative human land use in producing landscape disturbance for amphibians. At the same time, we also evaluated the effect of changing climatic conditions as additional potential drivers of population decline. Another goal was to determine whether and to what extent the existing nature reserves have been effective in protecting species in recent decades. Methods We used generalised additive models (GAMs) to investigate the association between the state (stable/decline) of amphibian populations in 5 × 5 km cells in central Italy and proxies of different typology of anthropogenic stressors, climatic variables and protection measures. Key results We found a significant association between anthropogenic landscape modifications and species decline. This negative relationship was revealed with agricultural predictors for the majority of the species, whereas urban fabrics had a slightly smaller impact. We found significant associations between amphibian declines and climatic variation, particularly the increasing number of dry days. Protected areas protected declines of two species only. Conclusions Our results showed that the status of amphibians in this region warrants greater attention than has been given previously. The detrimental effect of agricultural practices, combined with increasing aridity, makes amphibian populations particularly susceptible to extinction, and the conservation measures applied till now are inadequate for species protection in this region. Implications Our results should stimulate the implementation of environmental policies that focus not only on the protection of single habitats, but also on ensuring the environmental quality of the surrounding landscapes. Moreover, an adaptive management approach should be applied to take into account future modification of hydrology and climate.

scholarly journals Climate change and the risks associated with delayed breeding in a tropical wild bird population

2011 ◽  
Vol 278 (1722) ◽  
pp. 3184-3190 ◽  
Author(s):  
Deepa Senapathi ◽  
Malcolm A. C. Nicoll ◽  
Celine Teplitsky ◽  
Carl G. Jones ◽  
Ken Norris
Keyword(s):  
Climate Change ◽  
Wild Bird ◽  
Population Decline ◽  
Biodiversity Loss ◽  
Climatic Conditions ◽  
Timing Of Breeding ◽  
Wild Populations ◽  
Bird Population ◽  
Island Endemic

There is growing evidence of changes in the timing of important ecological events, such as flowering in plants and reproduction in animals, in response to climate change, with implications for population decline and biodiversity loss. Recent work has shown that the timing of breeding in wild birds is changing in response to climate change partly because individuals are remarkably flexible in their timing of breeding. Despite this work, our understanding of these processes in wild populations remains very limited and biased towards species from temperate regions. Here, we report the response to changing climate in a tropical wild bird population using a long-term dataset on a formerly critically endangered island endemic, the Mauritius kestrel. We show that the frequency of spring rainfall affects the timing of breeding, with birds breeding later in wetter springs. Delays in breeding have consequences in terms of reduced reproductive success as birds get exposed to risks associated with adverse climatic conditions later on in the breeding season, which reduce nesting success. These results, combined with the fact that frequency of spring rainfall has increased by about 60 per cent in our study area since 1962, imply that climate change is exposing birds to the stochastic risks of late reproduction by causing them to start breeding relatively late in the season.

scholarly journals Panthera tigris jacksoni Population Crash and Impending Extinction due to Environmental Perturbation and Human-Wildlife Conflict

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1032
Author(s):  
Dennis Choon Yung Ten ◽  
Rohana Jani ◽  
Noor Hashida Hashim ◽  
Salman Saaban ◽  
Abdul Kadir Abu Hashim ◽  
...  
Keyword(s):  
Population Decline ◽  
Management Plan ◽  
Peninsular Malaysia ◽  
Panthera Tigris ◽  
Canine Distemper ◽  
Environmental Perturbation ◽  
Population Crash ◽  
Tiger Conservation ◽  
Near Future ◽  
Human Wildlife Conflict

The critically endangered Malayan tiger (Panthera tigris jacksoni), with an estimated population of less than 200 individuals left in isolated rainforest habitats in Malaysia, is in an intermediate population crash leading to extinction in the next decade. The population has decreased significantly by illegal poaching, environmental perturbation, roadkill, and being captured during human–wildlife conflicts. Forty-five or more individuals were extracted from the wild (four animals captured due to conflict, one death due to canine distemper, one roadkilled, and 39 poached) in the 12 years between 2008–2019. The Malayan tigers are the first wildlife species to test positive for COVID-19 and are subject to the Canine Distemper Virus. These anthropogenic disturbances (poaching and human–tiger conflict) and environmental perturbation (decreasing habitat coverage and quality) have long been identified as impending extinction factors. Roadkill and infectious diseases have emerged recently as new confounding factors threatening Malayan tiger extinction in the near future. Peninsular Malaysia has an existing Malayan tiger conservation management plan; however, to enhance the protection and conservation of Malayan tigers from potential extinction, the authority should reassess the existing legislation, regulation, and management plan and realign them to prevent further population decline, and to better enable preparedness and readiness for the ongoing pandemic and future threats.

scholarly journals Stabilization of cultural innovations depends on population density: testing an epidemiological model of cultural evolution against a global dataset of rock art sites and climate-based estimates of ancient population densities

2019 ◽  
Author(s):  
Richard Walker ◽  
Anders Eriksson ◽  
Camille Ruiz ◽  
Taylor Howard Newton ◽  
Francesco Casalegno
Keyword(s):  
Population Density ◽  
Cultural Evolution ◽  
Rock Art ◽  
Empirical Support ◽  
Necessary Condition ◽  
Critical Threshold ◽  
Population Densities ◽  
Value Analysis ◽  
Ancient Population ◽  
Independent Population

AbstractDemographic models of human cultural evolution have high explanatory potential but weak empirical support. Here we use a global dataset of rock art sites and climate and genetics-based estimates of ancient population densities to test a new model based on epidemiological principles. The model focuses on the process whereby a cultural innovation becomes endemic in a population. It predicts that this cannot occur unless population density exceeds a critical value. Analysis of the data, using a Bayesian statistical framework, shows that the model has stronger empirical support than a null model, where rock art detection rates and population density are independent, or a proportional model where detection is directly proportional to population density. Comparisons between results for different geographical areas and periods yield qualitatively similar results, supporting the robustness of the model. Re-analysis of the rock art data, using a second set of independent population estimates, yields similar results. We conclude that population density above a critical threshold is a necessary condition for the maintenance of rock art as a stable part of a population’s cultural repertoire. Methods similar to those described can be used to test the model for other classes of archaeological artifact and to compare it against other models.

scholarly journals ‘Gigante’ cactus pear cultivated at different population densities in a mechanizable arrangement

2020 ◽  
Vol 24 (11) ◽  
pp. 769-775 ◽  
Author(s):  
Varley A. Fonseca ◽  
Luzinaldo C. Costa ◽  
João A. da Silva ◽  
Sérgio L. R. Donato ◽  
Paulo E. R. Donato ◽  
...  
Keyword(s):  
Socioeconomic Development ◽  
Dry Matter ◽  
Climatic Conditions ◽  
Semiarid Region ◽  
Population Densities ◽  
Cactus Pear ◽  
Area Index ◽  
Maximum Value ◽  
Brazilian Semiarid ◽  
Potential Acidity

ABSTRACT Cactus pear is a crop adapted to the climatic conditions of the Brazilian semiarid region, so it has contributed to the socioeconomic development of this region. The objective of this study was to evaluate the response of ‘Gigante’ cactus pear cultivated at different population densities in a mechanizable arrangement. The experimental design was in randomized blocks, with six population densities: 22,857; 34,286; 51,428; 62,857; 80,000 and 95,000 plants ha-1 and four repetitions. The following variables were evaluated: plant height, number of cladodes, cladode length, cladode width and cladode area index, green and dry matter yields, extraction/export of nutrients and soil chemical characteristics. Increase in population density in a mechanizable arrangement decreases the number of cladodes and increases the cladode area index. The maximum green and dry matter yield of cactus pear cultivated in arrangement that allows mechanization is expected with populations of 69,111.79 and 64,445.91 plants ha-1, respectively. Maximum values of extraction/export of nutrients in cactus pear tissue are expected at intermediate population densities (62,721.52-74,741.93 plants ha-1). Soil potential acidity has maximum value with 64,525.51 plants ha-1.

scholarly journals The Effect of Land Characteristics on Agricultural Productivity Using Multiple Linear Regression Method in Madiun Regency, East Java

2021 ◽  
Vol 325 ◽  
pp. 02005
Author(s):  
Elya Pratiwi Istifaroh ◽  
Rika Harini
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Agricultural Productivity ◽  
Secondary Data ◽  
Climatic Conditions ◽  
Linear Regression Method ◽  
Agricultural Commodities ◽  
Agricultural Commodity ◽  
Regression Methods

Agriculture is an important sector to support national food availability. Soil and climatic conditions in Indonesia are very suitable for agriculture. However, the land characteristics in each region are different, Especially in Madiun Regency, where this study is conducted. This study aims to determine what commodities are suitable for the characteristics of the land based on land suitability and how land characteristics influence agricultural productivity. The data used in this research is secondary data. Determination of agricultural commodities is carried out by cross-checking between land characteristics and guidelines for agricultural commodity land requirements. There are six types of agricultural commodities that are suitable for land characteristics in Madiun Regency. The effect of land characteristics consisting of several parameters on agricultural productivity was sought using multiple linear regression methods. The processing results are known that 8 variables of land characteristics significantly affect agricultural productivity by 93%. The independent variables were tested using the Simultaneous F-Test and were known to have a simultaneous (together) effect on agricultural productivity. In addition, a Partial T-Test was conducted, and it was found that there were only two variables that had a partial effect, namely the soil CEC characteristics and the sand characteristics.

scholarly journals Impact of model assumptions on demographic inferences: the case study of two sympatric mouse lemurs in northwestern Madagascar

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Helena Teixeira ◽  
Jordi Salmona ◽  
Armando Arredondo ◽  
Beatriz Mourato ◽  
Sophie Manzi ◽  
...  
Keyword(s):  
Population Structure ◽  
Population Size ◽  
Forest Cover ◽  
Population Decline ◽  
Population Expansion ◽  
Climatic Conditions ◽  
Population Connectivity ◽  
Primate Species ◽  
Last Interglacial ◽  
Quaternary Climate

Abstract Background Quaternary climate fluctuations have been acknowledged as major drivers of the geographical distribution of the extraordinary biodiversity observed in tropical biomes, including Madagascar. The main existing framework for Pleistocene Malagasy diversification assumes that forest cover was strongly shaped by warmer Interglacials (leading to forest expansion) and by cooler and arid glacials (leading to forest contraction), but predictions derived from this scenario for forest-dwelling animals have rarely been tested with genomic datasets. Results We generated genomic data and applied three complementary demographic approaches (Stairway Plot, PSMC and IICR-simulations) to infer population size and connectivity changes for two forest-dependent primate species (Microcebus murinus and M. ravelobensis) in northwestern Madagascar. The analyses suggested major demographic changes in both species that could be interpreted in two ways, depending on underlying model assumptions (i.e., panmixia or population structure). Under panmixia, the two species exhibited larger population sizes across the Last Glacial Maximum (LGM) and towards the African Humid Period (AHP). This peak was followed by a population decline in M. ravelobensis until the present, while M. murinus may have experienced a second population expansion that was followed by a sharp decline starting 3000 years ago. In contrast, simulations under population structure suggested decreasing population connectivity between the Last Interglacial and the LGM for both species, but increased connectivity during the AHP exclusively for M. murinus. Conclusion Our study shows that closely related species may differ in their responses to climatic events. Assuming that Pleistocene climatic conditions in the lowlands were similar to those in the Malagasy highlands, some demographic dynamics would be better explained by changes in population connectivity than in population size. However, changes in connectivity alone cannot be easily reconciled with a founder effect that was shown for M. murinus during its colonization of the northwestern Madagascar in the late Pleistocene. To decide between the two alternative models, more knowledge about historic forest dynamics in lowland habitats is necessary. Altogether, our study stresses that demographic inferences strongly depend on the underlying model assumptions. Final conclusions should therefore be based on a comparative evaluation of multiple approaches.

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