What Can Stable Isotope Analysis of Top Predator Tissues Contribute to Monitoring of Tundra Ecosystems?

Understanding how climate change and increasing human impacts may exert pressure on ecosystems and threaten biodiversity requires efficient monitoring programs. Indicator species have been proposed as useful tools, and predators and their diet may be particularly suitable. The vast and remote arctic tundra represents a good case study as shifts in ecosystem states are presently occurring, and monitoring is a major challenge. Here we assess what stable isotopes reflecting the diet of the arctic fox, a widespread and highly flexible top predator, can contribute to effective monitoring of the vertebrate prey basis of Arctic tundra. We used data collected over 2–5 years from six sites in the Eurasian Arctic and Greenland. Stable isotope signatures of arctic fox winter fur reflected both spatial and temporal variability in the composition of the vertebrate prey basis. Clear contrasts were apparent in the importance of marine resources, as well as of small rodents and their multiannual density fluctuations. Some important resources could however not be separated because of confounding isotopic signatures. Moreover, except for preferred prey, the proportions of prey in the diet may not necessarily reflect the relative importance of species in the community of available prey. Knowing these limitations, we suggest that the arctic fox diet as inferred from stable isotopes could serve as one of several key targets in ecosystem-based monitoring programs.</p

Data file 1 from Taking the beat of the Arctic: are lemming population cycles changing due to winter climate?

Original data file for the analysis of cyclic patterns in lemming population

Data file 2 from Taking the beat of the Arctic: are lemming population cycles changing due to winter climate?

Original data file for the analysis of lemming abundance in relation to snow variable

Supplementary material from Taking the beat of the Arctic: are lemming population cycles changing due to winter climate?

This file contains supplementary Mateiral and Methods, the description of data files, supplementary figures and supplementary table

Harmonizing circumpolar monitoring of Arctic fox: benefits, opportunities, challenges and recommendations

The biodiversity working group of the Arctic Council has developed pan-Arctic biodiversity monitoring plans to improve our ability to detect, understand and report on long-term change in Arctic biodiversity. The Arctic fox (Vulpes lagopus) was identified as a target of future monitoring because of its circumpolar distribution, ecological importance and reliance on Arctic ecosystems. We provide the first exhaustive survey of contemporary Arctic fox monitoring programmes, describing 34 projects located in eight countries. Monitored populations covered equally the four climate zones of the species’ distribution, and there were large differences between populations in long-term trends, multi-annual fluctuations, diet composition, degree of competition with red fox and human interferences. Den density, number of active dens, number of breeding dens and litter size were assessed in almost all populations, while projects varied greatly with respect to monitoring of other variables indicative of population status, ecosystem state or ecosystem function. We review the benefits, opportunities and challenges to increased integration of monitoring projects. We argue that better harmonizing protocols of data collection and data management would allow new questions to be addressed while adding tremendous value to individual projects. However, despite many opportunities, challenges remain. We offer six recommendations that represent decisive progress toward a better integration of Arctic fox monitoring projects. Further, our work serves as a template that can be used to integrate monitoring efforts of other species, thereby providing a key step for future assessments of global biodiversity

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. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective

Harmonizing circumpolar monitoring of Arctic fox: benefits, opportunities, challenges and recommendations

The biodiversity working group of the Arctic Council has developed pan-Arctic biodiversity monitoring plans to improve our ability to detect, understand and report on long-term change in Arctic biodiversity. The Arctic fox (Vulpes lagopus) was identified as a target of future monitoring because of its circumpolar distribution, ecological importance and reliance on Arctic ecosystems. We provide the first exhaustive survey of contemporary Arctic fox monitoring programmes, describing 34 projects located in eight countries. Monitored populations covered equally the four climate zones of the species’ distribution, and there were large differences between populations in long-term trends, multi-annual fluctuations, diet composition, degree of competition with red fox and human interferences. Den density, number of active dens, number of breeding dens and litter size were assessed in almost all populations, while projects varied greatly with respect to monitoring of other variables indicative of population status, ecosystem state or ecosystem function. We review the benefits, opportunities and challenges to increased integration of monitoring projects. We argue that better harmonizing protocols of data collection and data management would allow new questions to be addressed while adding tremendous value to individual projects. However, despite many opportunities, challenges remain. We offer six recommendations that represent decisive progress toward a better integration of Arctic fox monitoring projects. Further, our work serves as a template that can be used to integrate monitoring efforts of other species, thereby providing a key step for future assessments of global biodiversity