“…The H1 populations had the opportunity to spread by following establishment of wheat fields in the Loess Plateau and the North China Plain. The expansion scale of wheat fields and deforestation was unprecedented (Anderson, 2019 ), creating large areas of anthropogenic grasslands that were no longer constrained in river valleys. The distribution of H1 has been thus more extended than those of its predecessors.…”
Reconstructing the dispersal routes of pathogens can help identify the key drivers of their evolution and provides a basis for disease control. The cereal cyst nematode
Heterodera avenae
is one of the major nematode pests on cereals that can cause 10%–90% crop yield losses worldwide. Through extensive sampling on wheat and grasses, the Chinese population of
H. avenae
is widely identified in virtually all wheat growing regions in China, with H1 being the predominant haplotype. The monoculture of wheat in north China might have been the key driver for the prevalence of H1 population, which should date no earlier than the Han Dynasty (202 BCE–220 CE). Molecular phylogenetic and biogeographic analyses of Chinese
H. avenae
suggest a Pleistocene northwest China origin and an ancestral host of grasses. We assume that the prosperity of
Heterodera
in this region is a result of their preference for cooler climate and various grass hosts, which only appeared after the uplift of Qinghai‐Tibetan Plateau and aridification of Inner Asia. Nematode samples from the current and historical floodplains show a significant role of the Yellow River in the distribution of Chinese
H. avenae
. Whereas mechanical harvesters that operate on an inter‐provincial basis suggest the importance in the transmission of this species in eastern China in recent times. This study highlights the role of environmental change, river dynamics, and anthropogenic factors in the origin and long‐distance dissemination of pathogens.
“…The H1 populations had the opportunity to spread by following establishment of wheat fields in the Loess Plateau and the North China Plain. The expansion scale of wheat fields and deforestation was unprecedented (Anderson, 2019 ), creating large areas of anthropogenic grasslands that were no longer constrained in river valleys. The distribution of H1 has been thus more extended than those of its predecessors.…”
Reconstructing the dispersal routes of pathogens can help identify the key drivers of their evolution and provides a basis for disease control. The cereal cyst nematode
Heterodera avenae
is one of the major nematode pests on cereals that can cause 10%–90% crop yield losses worldwide. Through extensive sampling on wheat and grasses, the Chinese population of
H. avenae
is widely identified in virtually all wheat growing regions in China, with H1 being the predominant haplotype. The monoculture of wheat in north China might have been the key driver for the prevalence of H1 population, which should date no earlier than the Han Dynasty (202 BCE–220 CE). Molecular phylogenetic and biogeographic analyses of Chinese
H. avenae
suggest a Pleistocene northwest China origin and an ancestral host of grasses. We assume that the prosperity of
Heterodera
in this region is a result of their preference for cooler climate and various grass hosts, which only appeared after the uplift of Qinghai‐Tibetan Plateau and aridification of Inner Asia. Nematode samples from the current and historical floodplains show a significant role of the Yellow River in the distribution of Chinese
H. avenae
. Whereas mechanical harvesters that operate on an inter‐provincial basis suggest the importance in the transmission of this species in eastern China in recent times. This study highlights the role of environmental change, river dynamics, and anthropogenic factors in the origin and long‐distance dissemination of pathogens.
“…For instance, Peregrine recently explored a wide selection of societies from the Little Ice Age period often implicated as causing major societal disruptions across Eurasia, finding that not every society impacted by this cooling experienced comparable disruption [ 22 ]. Likewise, scholars continue to disagree about the role of adverse climate conditions in felling a number of large imperial polities in China over the past two millennia; some argue that the correlation between environment and socio-political or economic crises is inconsistent across cases [ 23 ], while others point to a persistent temporal association between volcanically forced cooling and dynastic transition or collapse, at the same time noting that the scale of volcanic forcing operates interactively with the scale of pre-existing socio-political and economic stress [ 24 ]. Figure 2 Global anomalous temperatures in °C compared to the 1961–1990 mean, showing dynamics for East Asia (red), Europe (blue) and South America (green).…”
Section: Complex Relationships Between Environmental and Societal Dyn...mentioning
Climate variability and natural hazards like floods and earthquakes can act as environmental shocks or socioecological stressors leading to instability and suffering throughout human history. Yet, societies experience a wide range of outcomes when facing such challenges: some suffer from social unrest, civil violence or complete collapse; others prove more resilient and maintain key social functions. We currently lack a clear, generally agreed-upon conceptual framework and evidentiary base to explore what causes these divergent outcomes. Here, we discuss efforts to develop such a framework through the Crisis Database (CrisisDB) programme. We illustrate that the impact of environmental stressors is mediated through extant cultural, political and economic structures that evolve over extended timescales (decades to centuries). These structures can generate high resilience to major shocks, facilitate positive adaptation, or, alternatively, undermine collective action and lead to unrest, violence and even societal collapse. By exposing the ways that different societies have reacted to crises over their lifetime, this framework can help identify the factors and complex social–ecological interactions that either bolster or undermine resilience to contemporary climate shocks.
This article is part of the theme issue ‘Climate change adaptation needs a science of culture’.
“…For instance, Peregrine recently explored a wide selection of societies from the Little Ice Age period often implicated as causing major societal disruptions across Eurasia, finding that not every society impacted by this cooling experienced comparable disruption (22). Likewise, scholars continue to disagree about the role of adverse climate conditions in felling a number of large imperial polities in China over the past two millennia; some argue that the correlation between environment and socio-political or economic crises is inconsistent across cases (23), while others point to a persistent temporal association between volcanically-forced cooling and dynastic transition or collapse, at the same time noting that the scale of volcanic forcing operates interactively with the scale of pre-existing socio-political and economic stress (24). Other stressors, including weather-related phenomena such as floods or droughts and associated ecological shocks, are more regionally and temporally focussed than evolving climate regimes and generally better matched to the social scales that are typically explored in historical accounts.…”
Section: Complex Relationships Between Environmental and Societal Dyn...mentioning
Climate variability and natural hazards like floods and earthquakes can act as environmental shocks or socioecological stressors leading to instability and suffering throughout human history. Yet, societies experience a wide range of outcomes when facing such challenges: some suffer from social unrest, civil violence, or complete collapse; others prove more resilient and maintain key social functions. We currently lack a clear, generally agreed-upon conceptual framework and evidentiary base to explore what causes these divergent outcomes. Here, we discuss efforts to develop such a framework through the Crisis Database (CrisisDB) programme. We illustrate that the impact of environmental stressors is mediated through extant cultural, political, and economic structures that evolve over extended timescales (decades to centuries). These structures can generate high resilience to major shocks, facilitate positive adaptation, or, alternatively, undermine collective action and lead to unrest, violence, and even societal collapse. By exposing the ways that different societies have reacted to crises over their lifetime, this framework can help identify the factors and complex social-ecological interactions that either bolster or undermine resilience to contemporary climate shocks.
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