Many marine fish species are experiencing population declines, but their extinction risk profiles are largely understudied in comparison to their terrestrial vertebrate counterparts. Selective extinction of marine fish species may result in rapid alteration of the structure and function of ocean ecosystems. In this study, we compiled an ecological trait dataset for 8,185 species of marine ray-finned fishes (class Actinopterygii) from FishBase and used phylogenetic generalized linear models to examine which ecological traits are associated with increased extinction risk, based on the International Union for the Conservation of Nature Red List. We also assessed which threat types may be driving these species toward greater extinction risk and whether threatened species face a greater average number of threat types than non-threatened species. We found that larger body size and/or fishes with life histories involving movement between marine, brackish, and freshwater environments are associated with elevated extinction risk. Commercial harvesting threatens the greatest number of species, followed by pollution, development, and then climate change. We also found that threatened species, on average, face a significantly greater number of threat types than non-threatened species. These results can be used by resource managers to help address the heightened extinction risk patterns we found.

This paper draws upon documentary, visual and archaeological evidence to chart the development of the sacristy of Westminster Abbey from its construction as one of the earliest parts of the abbey’s thirteenth-century rebuilding to its demolition in the mid-eighteenth century − a story that reflects wider changes of religious and political history.

We use proprietary transaction data on interest rate swaps to assess the effects of centralized trading, as mandated by Dodd–Frank, on market quality. Contracts with the most extensive centralized trading see liquidity metrics improve by between 12% and 19% relative to those of a control group. This is driven by a clear increase in competition between dealers, particularly in U.S. markets. Additionally, centralized trading has caused interdealer trading in EUR swap markets to migrate from the United States to Europe. This is consistent with swap dealers attempting to avoid being captured by the trade mandate in order to maintain market power.

The Iranian Empire emerged in the third century in the interstices of the Silk Road that increasingly linked the markets of the Mediterranean and the Near East with South, Central, and East Asia. The ensuing four centuries of Iranian rule corresponded with the heyday of trans-Eurasian trade, as the demand of moneyed imperial elites across the continent for one another's high-value commodities stimulated the development of long-distance networks. Despite its position at the nexus of trans-continental and trans-oceanic commerce, accounts of Iran in late antiquity relegate trade to a marginal role in its political economy. The present article seeks to foreground the contribution of trans-continental mercantile networks to the formation of Iran and to argue that its development depended as much on the political economies of its western and eastern neighbours as on internal Near Eastern factors.

Understanding the long-term ecological dynamics of boreal forests is essential for assessment of the possible responses and feedbacks of forest ecosystems to climate change. New data on past forest dynamics and peatland development were obtained from a peat sequence in the southern Valdai Hills (European Russia) based on pollen, plant macrofossil, micro-charcoal, peat humification, and testate amoeba analyses. The results demonstrate a dominance of broadleaved forests in the study area from 7000–4000 cal yr BP. Picea was initially a minor component of this forest but increased in cover rapidly with climatic cooling beginning at 4000 cal yr BP, becoming the dominant species. Broadleaved species persisted until 900 cal yr BP, with evidence for intensified felling and forest management over recent centuries. Over the last four hundred years there is evidence for widespread paludification and the establishment of Picea-Sphagnum forests. These data demonstrate how modern wet woodlands have been shaped by a combination of climatic and anthropogenic factors over several millennia. The results also demonstrate the value of a multiproxy approach in understanding long-term forest ecology.

Predictions of marine ice-sheet behaviour require models able to simulate grounding-line migration. We present results of an intercomparison experiment for plan-view marine ice-sheet models. Verification is effected by comparison with approximate analytical solutions for flux across the grounding line using simplified geometrical configurations (no lateral variations, no buttressing effects from lateral drag). Perturbation experiments specifying spatial variation in basal sliding parameters permitted the evolution of curved grounding lines, generating buttressing effects. The experiments showed regions of compression and extensional flow across the grounding line, thereby invalidating the boundary layer theory. Steady-state grounding-line positions were found to be dependent on the level of physical model approximation. Resolving grounding lines requires inclusion of membrane stresses, a sufficiently small grid size (<500 m), or subgrid interpolation of the grounding line. The latter still requires nominal grid sizes of <5 km. For larger grid spacings, appropriate parameterizations for ice flux may be imposed at the grounding line, but the short-time transient behaviour is then incorrect and different from models that do not incorporate grounding-line parameterizations. The numerical error associated with predicting grounding-line motion can be reduced significantly below the errors associated with parameter ignorance and uncertainties in future scenarios.

Holocene climatic variability and human impact on vegetation are reconstructed from a region in central European Russia, which lies at an important ecotone between broadleaf forest and steppe. For the first time in this region we adopt a multi-proxy approach that combines analysis of local mire conditions from plant macrofossil and testate amoeba analyses with pollen-based quantitative climate reconstruction. The proxies indicate a long-term warming trend from 9700 to 7500 cal yr BP, interrupted by a series of short-term cold events. From 7500 to 5000 cal yr BP the results imply a relatively stable climate, warmer and drier than present, spanning the Holocene Thermal Maximum. Since 5000 cal yr BP the data suggest a change to cooler climate, but with centennial-scale variability. This shift at around 5000 cal yr BP is supported by extensive evidence from other sites. In the early Holocene, the region was occupied mainly by pine and birch forests. Broad-leafed forests of oak, lime and elm expanded after 7800 cal yr BP and remained dominant until the last few centuries. During the historical period, vegetation changes have been driven mainly by human activities.

Cryptotephrochronology, the use of hidden, diminutive volcanic ash layers to date sediments, has rarely been applied outside western Europe but has the potential to improve the tephrochronology of other regions of the world. Here we present the first comprehensive cryptotephra study in Alaska. Cores were extracted from five peatland sites, with cryptotephras located by ashing and microscopy and their glass geochemistry examined using electron probe microanalysis. Glass geochemical data from nine tephras were compared between sites and with data from previous Alaskan tephra studies. One tephra present in all the cores is believed to represent a previously unidentified eruption of Mt. Churchill and is named here as the ‘Lena tephra’. A mid-Holocene tephra in one site is very similar to Aniakchak tephra and most likely represents a previously unidentified Aniakchak eruption, ca. 5300–5030 cal yr BP. Other tephras are from the late Holocene White River eruption, a mid-Holocene Mt. Churchill eruption, and possibly eruptions of Redoubt and Augustine volcanoes. These results show the potential of cryptotephras to expand the geographic limits of tephrochronology and demonstrate that Mt. Churchill has been more active in the Holocene than previously appreciated. This finding may necessitate reassessment of volcanic hazards in the region.

Peatlands are widely exploited archives of paleoenvironmental change. We developed and compared multiple transfer functions to infer peatland depth to the water table (DWT) and pH based on testate amoeba (percentages, or presence/absence), bryophyte presence/absence, and vascular plant presence/absence data from sub-alpine peatlands in the SE Swiss Alps in order to 1) compare the performance of single-proxy vs. multi-proxy models and 2) assess the performance of presence/absence models. Bootstrapping cross-validation showing the best performing single-proxy transfer functions for both DWT and pH were those based on bryophytes. The best performing transfer functions overall for DWT were those based on combined testate amoebae percentages, bryophytes and vascular plants; and for pH, those based on testate amoebae and bryophytes. The comparison of DWT and pH inferred from testate amoeba percentages and presence/absence data showed similar general patterns but differences in the magnitude and timing of some shifts. These results show new directions for paleoenvironmental research, 1) suggesting that it is possible to build good-performing transfer functions using presence/absence data, although with some loss of accuracy, and 2) supporting the idea that multi-proxy inference models may improve paleoecological reconstruction. The performance of multi-proxy and single-proxy transfer functions should be further compared in paleoecological data.

Various spatial discretizations for the ice sheet are compared for accuracy against analytical solutions in one and two dimensions. The computational efficiency of various iterated and non-iterated marching schemes is compared.

The stability properties of different marching schemes, with and without iterations on the non-linear equations, are compared. Newton–Raphson techniques permit the largest time steps. A new technique, which is based on the fact that the dynamics of unstable iterated maps contain information about where the unstable root lies, is shown to improve substantially the performance of Picard iteration at a negligible computational cost.

In the Iranian Empire (226–636 CE), jurists drawn from the ranks of the Zoroastrian priestly elite developed a complex of institutions designed to guarantee the reproduction of aristocratic males as long as the empire endured. To overcome the high rate of mortality characteristic of preindustrial demographic regimes, they aimed to maximize the fertility rate without compromising their endogamous ideals through the institutions of reproductive coercion, temporary marriage, and “substitute-successorship.” Occupying a position between the varieties of monogamy and polygyny hitherto practiced in the Ancient Near East, the Iranian organization of sex enabled elites not only to reproduce their patrilineages reliably across multiple generations, but also to achieve an appropriate ratio of resources to number of offspring. As the backbone of this juridical architecture, the imperial court became the anchor of aristocratic power, and ruling and aristocratic dynasties became increasingly intertwined and interdependent, forming the patrilineal networks of the “Iranians”—the agents and beneficiaries of Iranian imperialism. The empire's aristocratic structure took shape through a sexual economy: the court created and circulated sexual and reproductive incentives that incorporated elite males into its network that was, thanks to its politically enhanced inclusive fitness, reliable and reproducible. In demonstrating the centrality of Zoroastrian cosmology to the construction and operation of the relevant juridical institutions, I seek to join the approaches of evolutionary biology and cultural anthropology to reproduction that have been pursued in opposition, to account for the historical role of sex in the consolidation of the Iranian Empire.

This article is an exploration of the interconnected legal ties between Christians and Zoroastrians in the early Islamic era. Drawing from the writings of the Christian authors Ishobokt, Simeon, and Henanisho, Payne describes how East Syrian bishops appropriated laws of marriage, inheritance, and property from Iranian jurisprudential traditions as a means of transferring wealth intergenerationally and extending their judicial authority. Payne thus explores the ways in which the Christians of Iran were influenced by the Iranian legal system and culture and in the seventh century CE.