Changing patterns of human resource use and food consumption have profoundly impacted the Earth's biosphere. Until now, no individual taxa have been suggested as distinct and characteristic new morphospecies representing this change. Here we show that the domestic broiler chicken is one such potential marker. Human-directed changes in breeding, diet and farming practices demonstrate at least a doubling in body size from the late medieval period to the present in domesticated chickens, and an up to fivefold increase in body mass since the mid-twentieth century. Moreover, the skeletal morphology, pathology, bone geochemistry and genetics of modern broilers are demonstrably different to those of their ancestors. Physical and numerical changes to chickens in the second half of the twentieth century, i.e. during the putative Anthropocene Epoch, have been the most dramatic, with large increases in individual bird growth rate and population sizes. Broiler chickens, now unable to survive without human intervention, have a combined mass exceeding that of all other birds on Earth; this novel morphotype symbolizes the unprecedented human reconfiguration of the Earth's biosphere.
Agriculture has played a pivotal role in shaping landscapes, soils and vegetation. Developing a better understanding of early farming practices can contribute to wider questions regarding the long-term impact of farming and its nature in comparison with present-day traditional agrosystems. In this study we determine stable carbon and nitrogen isotope values of barley grains from a series of present-day traditionally managed farming plots in Morocco, capturing a range of annual rainfall and farming practices. This allows a framework to be developed to refine current isotopic approaches used to infer manuring intensity and crop water status in (semi-)arid regions. This method has been applied to charred crop remains from two early farming sites in the eastern Mediterranean: Abu Hureyra and 'Ain Ghazal. In this way, our study enhances knowledge of agricultural practice in the past, adding to understanding of how people have shaped and adapted to their environment over thousands of years.
This paper presents new carbon, nitrogen and sulphur isotope data for European fallow deer (Dama dama dama) in Roman Britain and discusses results in light of evidence from classical texts, landscape archaeology, zooarchaeology and the limited available samples of metric data. The new isotope data presented here are from Fishbourne Roman Palace (Sussex), two sites on the Isle of Thanet (Kent) and a further two sites in London. In spite of small sample sizes the data make an important contribution to the very limited corpus of scientific research on the species and provide new resolution to the nature of fallow deer movement and management in Roman Britain.
Xiang et al. (1) assert that chickens were domesticated on the North China plain 10,000 y ago. Although a great deal remains unknown about the temporal and geographic origins of poultry husbandry, this claim is extraordinary. We welcome the increasing application of modern bioarcheological techniques to questions pertaining to animal domestication in China, but we are skeptical about these conclusions for several reasons. Firstly, their claim that chickens were domesticated on the North China plain is problematic because this region is currently climatically unsuitable for their wild ancestor (the red jungle fowl). In support of this assertion, they point to the abundance of tropical animals at the sites of Nanzhuangtou and Cishan. High-resolution paleoclimatic records (2) suggest, however, that before the mid-Holocene, cooler temperate conditions prevailed between 35°N and 40°N (hence the dominance of Palaearctic species at Nanzhuangtou). Although higher (+2-4°C) average temperatures in the mid-Holocene supported the presence of an Indomalayan mammalian complex, the species identified are present today above 30°N. In contrast, red jungle fowl populations in China do not exist north of 23°N. This evidence suggests that an environment suitable for thermophile red jungle fowl did not exist at the sites of Cishan or Wangyin. In addition, although cooler temperatures would allow for enhanced DNA preservation, the predicted (thermal-age.eu) mean fragment lengths of 23 bp and 31 bp for Nanzhuangtou and Cishan, respectively, appear at odds with the described looped PCR protocol. Secondly, identifying Galliform bones to genus on the basis of their morphology is straightforward (3). In fact, studies of phasianid remains from across China (4) have revealed that although pheasants were identified at Neolithic Cishan and Wangyin, Gallus was only present in the Warring States Period tomb (476−221 B.C.) at Jiuliandun.
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