• Energy Research

Table of body mass of Sanderling (Calidris alba) chicks of varying ages (in days) at Zackenberg and Hochstetter Forland (northeast Greenland). Individuals are identified by their ringnumber and the family (NestID). Further information is found in the methods section of the publication.

Table of hatch dates of Sanderling (Calidris alba) clutches in Zackenberg, northeast Greenland. Hatch dates of clutches that successfully hatched are observed hatch dates. Hatch dates of clutches that did not hatch were estimates based on egg flotation, and those of broods are based on the estimated age of the chicks using a species-specific growth curve of body mass. Further information is found in the methods section of the publication.

Table of histories of Sanderling (Calidris alba) clutches in Zackenberg, northeast Greenland, 2007-2013. Columns contain data about (1) “Date found”, the day of the breeding season on which the nest was found; (2) “Date last checked when alive”, the last day the clutch was checked when alive; (3) “Date last checked”, the last day the clutch was checked; (4) “Fate”, the fate of the nest (0 = successfully hatched, 1 = depredated) and (5) “Hatch date”, the date of hatch, which was observed in case the clutch was successful, or estimated based on egg flotation, in case the clutch was not successful. Dates are scaled such that 10 June is day 1, the earliest date at which a clutch was found. Further information is found in the methods section of the publication.

Alpine and arctic lemming populations appear to be highly sensitive to climate change, and when faced with warmer and shorter winters, their well-known high-amplitude population cycles may collapse. Being keystone species in tundra ecosystems, changed lemming dynamics may convey significant knock-on effects on trophically linked species. Here, we analyse long-term (1988–2010), community-wide monitoring data from two sites in high-arctic Greenland and document how a collapse in collared lemming cyclicity affects the population dynamics of the predator guild. Dramatic changes were observed in two highly specialized lemming predators: snowy owl and stoat. Following the lemming cycle collapse, snowy owl fledgling production declined by 98 per cent, and there was indication of a severe population decline of stoats at one site. The less specialized long-tailed skua and the generalist arctic fox were more loosely coupled to the lemming dynamics. Still, the lemming collapse had noticeable effects on their reproductive performance. Predator responses differed somewhat between sites in all species and could arise from site-specific differences in lemming dynamics, intra-guild interactions or subsidies from other resources. Nevertheless, population extinctions and community restructuring of this arctic endemic predator guild are likely if the lemming dynamics are maintained at the current non-cyclic, low-density state.

Gyrfalcon (Falco rusticolus) is the largest falcon in the world. It inhabits a wide range of climate zones in the Northern Hemisphere, from boreal forests in the south of its range to the arid polar deserts of the High Arctic. In Greenland, because of the harsh, remote environments in which gyrfalcons live, research related to the contemporary and pre-modern periods has been limited to the north-west, central west and central east coasts, with no specific investigations being conducted for the north-east. Here, we report the first pre-modern record of a gyrfalcon in north-east Greenland, located at 80.4°N in Kronprins Christian Land. Skin tissue from a decaying gyrfalcon’s body was radiocarbon dated to 769–944 CE (common era) using a terrestrial-only calibration curve, and 1182–1456 CE using a marine-only calibration curve. Since the gyrfalcon has a mixed terrestrial/marine diet, the actual age can be said to belong between these two groups. This limited data, therefore places the presence of the gyrfalcon in north-east Greenland during a period of prolonged elevated temperatures and climate stress associated with the Medieval Climate Anomaly. Whether the gyrfalcon was part of a larger population or a straggler, and whether the species survived the whole of the Medieval Climate Anomaly in north-east Greenland, is unknown. Polar Research, 38 ISSN:0800-0395 ISSN:1751-8369

SummaryClimate change may influence the phenology of organisms unequally across trophic levels and thus lead to phenological mismatches between predators and prey. In cases where prey availability peaks before reproducing predators reach maximal prey demand, any negative fitness consequences would selectively favor resynchronization by earlier starts of the reproductive activities of the predators. At a study site in northeast Greenland, over a period of 17 years, the median emergence of the invertebrate prey of SanderlingCalidris albaadvanced with 1.27 days per year. Yet, over the same period Sanderling did not advance hatching date. Thus, Sanderlings increasingly hatched after their prey was maximally abundant. Surprisingly, the phenological mismatches did not affect chick growth, but the interaction of the annual width and height of the peak in food abundance did. Chicks grew especially better in years when the food peak was broad. Sanderling clutches were most likely to be depredated early in the season, which should delay reproduction. We propose that high early clutch predation may favor a later reproductive timing. Additionally, our data suggest that in most years food was still abundant after the median date of emergence, which may explain why Sanderlings did not advance breeding along with the advances in arthropod phenology.

This paper presents the results of a number of aircraft- and boat-based surveys for seabird breeding colonies in East and North Greenland carried out in the period 2003 to 2018 and gives the first comprehensive overview of the distribution and size of the seabird breeding colonies in this remote and mainly uninhabited region. Seventeen seabird species breed in approximately 800 sites distributed very unevenly along the coasts, with high concentrations at the polynyas and long stretches with very few breeding seabirds. Climate changes are in full progress in East and North Greenland, especially affecting the sea ice regime, and seabirds are expected to respond to these changes in different ways. For example, since the 1980s, Common Eiders (Somateria mollissima) have extended their breeding range more than two latitudinal degrees towards the north, now reaching the northernmost land on Earth. Lesser Black-backed Gulls (Larus fuscus) and Great Cormorants (Phalacrocorax carbo) have immigrated, and Sabine’s Gulls (Xema sabini) have increased and extended their range. Besides presenting survey results, this report may also serve as a baseline for future studies of the abundance of breeding seabirds in East and North Greenland.

Table of arthropod abundance in Zackenberg in the years 1996-2013 (excluding 2010). Columns contain data about Year, Date (day of year), and the number of individual arthropods per pitfall trap per day for the orders Aranea, Diptera, Hemiptera, Hymenoptera, Lepidoptera and Thysanoptera. Further information is found in the methods section of the publication. Data have been collected within the BioBasis programme of the Greenland Ecosystem Monitoring (GEM) and are publicly available via http://data.g-e-m.dk/.