Functional trait diversity is increasingly used to model future changes in community structure despite a poor understanding of community disassembly's effects on functional diversity. By tracking the functional diversity of the North American large mammal fauna through the End-Pleistocene megafaunal extinction and up to the present, I show that contrary to expectations, functionally unique species are no more likely to go extinct than functionally redundant species. This makes total functional richness loss no worse than expected given similar taxonomic richness declines.

To reduce greenhouse gas emissions in the coming decades, many governments will have to reform their energy policies. These policies are difficult to measure with any precision. As a result, it is unclear whether progress has been made towards important energy policy reforms, such as reducing fossil fuel subsidies. We use new data to measure net taxes and subsidies for gasoline in almost all countries at the monthly level and find evidence of both progress and backsliding. From 2003 to 2015, gasoline taxes rose in 83 states but fell in 46 states.

Researchers brave polar bears, mosquitoes and gull attacks in the Canadian Arctic to investigate an alarming die off.

Original Source

Climate change in Alaska is causing widespread environmental change that is damaging critical infrastructure. As climate change continues, infrastructure may become more vulnerable to damage, increasing risks to residents and resulting in large economic impacts. We quantified the potential economic damages to Alaska public infrastructure resulting from climate-driven changes in flooding, precipitation, near-surface permafrost thaw, and freeze–thaw cycles using high and low future climate scenarios. Additionally, we estimated coastal erosion losses for villages known to be at risk.

The frequency of large wildfires in western North America has been increasing in recent decades, yet the geochemical impacts of these events are poorly understood. The multidecadal timescales of both disturbance-regime variability and ecosystem responses make it challenging to study the effects of fire on terrestrial nutrient cycling. Nonetheless, disturbance-mediated changes in nutrient concentrations could ultimately limit forest productivity over centennial to millennial time scales.

A major factor for the population decline of Native Americans after European contact has been attributed to infectious disease susceptibility. To investigate whether a pre-existing genetic component contributed to this phenomenon, here we analyse 50 exomes of a continuous population from the Northwest Coast of North America, dating from before and after European contact.

Original Source

The emergence of HIV-1 group M subtype B in North American men who have sex with men was a key turning point in the HIV/AIDS pandemic. Phylogenetic studies have suggested cryptic subtype B circulation in the United States (US) throughout the 1970s and an even older presence in the Caribbean. However, these temporal and geographical inferences, based upon partial HIV-1 genomes that postdate the recognition of AIDS in 1981, remain contentious and the earliest movements of the virus within the US are unknown.

A study clarifies when HIV entered the United States and dispels the myth that one man instigated the AIDS epidemic in North America.

How will ecological communities change in response to climate warming? Direct effects of temperature and indirect cascading effects of species interactions are already altering the structure of local communities, but the dynamics of community change are still poorly understood. We explore the cumulative effects of warming on the dynamics and turnover of forest ant communities that were warmed as part of a 5-year climate manipulation experiment at two sites in eastern North America.

Extreme large-scale North American cold events are associated with strong undulations in the tropospheric jet stream which bring cold polar air southward over the continent. Here we propose that these jet undulations are associated with the North American part of the Circumglobal Teleconnection Pattern—a pair of zonally oriented waves of zonal wave number 5 which are in zonal quadrature with each other. While the Pacific/North American pattern is associated with the first circumglobal wave pattern, North American extreme cold events are associated with the second pattern.