TDF: A method for estimating stable isotope trophic discrimination in wild populations.

Stable isotope mixing models (SIMMs) are widely used for characterizing wild animal diets. Such models rely upon using accurate trophic discrimination factors (TDFs) to account for the digestion, incorporation, and assimilation of food. Existing methods to calculate TDFs rely on controlled feeding trials that are time-consuming, often impractical for the study taxon, and may not reflect natural variability of TDFs present in wild populations.

Author Correction: Arctic avian predators synchronise their spring migration with the northern progression of snowmelt.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Arctic avian predators synchronise their spring migration with the northern progression of snowmelt.

Migratory species display a range of migration patterns between irruptive (facultative) to regular (obligate), as a response to different predictability of resources. In the Arctic, snow directly influences resource availability. The causes and consequences of different migration patterns of migratory species as a response to the snow conditions remains however unexplored.

Correction to: Status and trends of circumpolar peregrine falcon and gyrfalcon populations.

While collating contributions and comments from 36 researchers, the coordinating authors accidentally omitted Dr. Suzanne Carrière from the list of contributing co-authors. Dr.

Arctic terrestrial biodiversity status and trends: A synopsis of science supporting the CBMP State of Arctic Terrestrial Biodiversity Report.

This review provides a synopsis of the main findings of individual papers in the special issue Terrestrial Biodiversity in a Rapidly Changing Arctic. The special issue was developed to inform the State of the Arctic Terrestrial Biodiversity Report developed by the Circumpolar Biodiversity Monitoring Program (CBMP) of the Conservation of Arctic Flora and Fauna (CAFF), Arctic Council working group. Salient points about the status and trends of Arctic biodiversity and biodiversity monitoring are organized by taxonomic groups: (1) vegetation, (2) invertebrates, (3) mammals, and (4) birds.

Status and trends of tundra birds across the circumpolar Arctic.

Tundra-breeding birds face diverse conservation challenges, from accelerated rates of Arctic climate change to threats associated with highly migratory life histories. Here we summarise the status and trends of Arctic terrestrial birds (88 species, 228 subspecies or distinct flyway populations) across guilds/regions, derived from published sources, raw data or, in rare cases, expert opinion. We report long-term trends in vital rates (survival, reproduction) for the handful of species and regions for which these are available.

Status and trends of circumpolar peregrine falcon and gyrfalcon populations.

The peregrine falcon (Falco peregrinus) and the gyrfalcon (Falco rusticolus) are top avian predators of Arctic ecosystems. Although existing monitoring efforts are well established for both species, collaboration of activities among Arctic scientists actively involved in research of large falcons in the Nearctic and Palearctic has been poorly coordinated. Here we provide the first overview of Arctic falcon monitoring sites, present trends for long-term occupancy and productivity, and summarize information describing abundance, distribution, phenology, and health of the two species.

Documenting lemming population change in the Arctic: Can we detect trends?

Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active.

Precipitation and ectoparasitism reduce reproductive success in an arctic-nesting top-predator.

Indirect impacts of climate change, mediated by new species interactions (including pathogens or parasites) will likely be key drivers of biodiversity reorganization. In addition, direct effects of extreme weather events remain understudied. Simultaneous investigation of the significance of ectoparasites on host populations and extreme weather events is lacking, especially in the Arctic.

Linking pre-laying energy allocation and timing of breeding in a migratory arctic raptor.

For migratory species, acquisition and allocation of energy after arrival on the breeding grounds largely determine reproductive decisions. Few studies have investigated underlying physiological mechanisms driving variation in breeding phenology so far. We linked physiological state to individual timing of breeding in pre-laying arctic-nesting female peregrine falcons (Falco peregrinus tundrius).

The influence of weather and lemmings on spatiotemporal variation in the abundance of multiple avian guilds in the arctic.

Climate change is occurring more rapidly in the Arctic than other places in the world, which is likely to alter the distribution and abundance of migratory birds breeding there. A warming climate can provide benefits to birds by decreasing spring snow cover, but increases in the frequency of summer rainstorms, another product of climate change, may reduce foraging opportunities for insectivorous birds. Cyclic lemming populations in the Arctic also influence bird abundance because Arctic foxes begin consuming bird eggs when lemmings decline.

Heavy rainfall increases nestling mortality of an Arctic top predator: experimental evidence and long-term trend in peregrine falcons.

Although animal population dynamics have often been correlated with fluctuations in precipitation, causal relationships have rarely been demonstrated in wild birds. We combined nest observations with a field experiment to investigate the direct effect of rainfall on survival of peregrine falcon (Falco peregrinus) nestlings in the Canadian Arctic. We then used historical data to evaluate if recent changes in the precipitation regime could explain the long-term decline of falcon annual productivity.

Landscape heterogeneity drives intra-population niche variation and reproduction in an arctic top predator.

While intra-population variability in resource use is ubiquitous, little is known of how this measure of niche diversity varies in space and its role in population dynamics. Here we examined how heterogeneous breeding environments can structure intra-population niche variation in both resource use and reproductive output. We investigated intra-population niche variation in the Arctic tundra ecosystem, studying peregrine falcon (Falco peregrinus tundrius, White) breeding within a terrestrial-marine gradient near Rankin Inlet, Nunavut, Canada.