Isotopic values of diet of Blastocerus dichotomus (marsh deer) in Paraná Basin,South America

The marsh deer (Blastocerus dichotomus, Illiger, 1815) is the largest contemporary South American deer, and its habitat includes the floodplains and wetlands of eastern South America. Throughout the Holocene these deer were widely used by indigenous societies, from the southern banks of the Amazon River to the Río de la Plata River, and from the Andean foothills to the Atlantic Ocean. However, despite the enormous ecological and archaeological importance of this ungulate in the region, our knowledge of the isotopic values of their diet is almost nonexistent. This paper is the first systematic approach to the study of the isotopic values of this mammal's diet, using archaeological and present-day samples from interconnected watersheds of the Paraná and Uruguay rivers in east-central Argentina. The results obtained from 24 measurements indicate an average value of ?21.09 ± 1.46‰ in δ¹³C collagen, with a low coefficient of variation (6.92%). The data indicate a marked preference for consumption of plants with a C₃ photosynthetic pathway. Most of the observed variability in the isotopic values corresponds to the period 900–1430 ¹⁴C years BP, a time range during which the values show higher consumption of C₄ plants. This it could be related with a period where temperature and associated humidity increased, synchronous in the area with the Medieval Climate Anomaly.     

Seasonal weather sensitivity,temperature thresholds,and climate change impacts for park visitation

Historical park visitation and weather data, taken at the daily time scale from 2000 to 2009 for Pinery Provincial Park in southern Ontario (Canada), were analysed as an objective measure of the weather sensitivity, temperature thresholds, and potential impacts of projected climate change for park visitation. Three seasonal weather-visitation models were constructed using multivariable linear regression (peak, shoulder, off-season). To account for both natural and institutional seasonality, the weather-visitation models included both climatic (temperature, precipitation) and social (weekends, holidays) variables, which demonstrated equably comparable effects on visitation across the three models. Critical temperature thresholds were identified for each season using one-way analysis of variance to determine the range of temperatures within which the threshold was evident; the specific degree of temperature associated with the threshold was identified within the seasonal regression models. Temperatures over 33 °C during the peak season and over 29 °C during the shoulder season indicated critical thresholds at which point conditions that were ‘too hot’ for some caused a decline in visitation. Furthermore, temperatures below 11 °C indicated another critical threshold, where conditions were ‘too cold’ for most and therefore park visitation was less sensitive to temperature variability below this threshold. A partial sensitivity analysis for the impact of a warmer, wetter climate on park visitation was conducted, illustrating the effect of a 1 °C to 5 °C warming in maximum temperatures, coupled with a 5% to 15% increase in total precipitation. In response to projected climate change, the weather-visitation models suggested that for each additional degree of warming experienced, despite the negative effects of increasing precipitation and more frequent heat extremes, annual park visitation could increase by 3.1%, annually. The projected increase in park visitation as a result of rising temperatures was mainly associated with shoulder season visitation, with only minor increases in peak season visitation.     

Hope in the Face of Temporal Devastation

This article evaluates Jonathan Lear's account of radical hope in light of the phenomenon of social acceleration. According to Lear's philosophical exegesis of the life of the Crow Nation's last chief, Plenty Coups, radical hope is hope based on the conviction that the world's goodness transcends but includes the goodness of human culture. Such hope enables a culture to persevere in the face of its own collapse through political humility, by which a culture draws on the resources of other cultures in order to revive itself. Social acceleration—which results in the warping of our sense of time as tensed between past, present, and future—demands a more primordial form of radical hope, based on the affirmation of the world's own temporalities as simultaneously resisting and sustaining our own cultural temporalities. This in turn involves a more self-critical form of political humility.