Jan Esefeld’s research while affiliated with Friedrich Schiller University Jena and other places

Despite the sensitivity of ecosystems in extreme conditions, only 0.029% of the Antarctic continent is currently granted special protection as Antarctic Specially Protected Area (ASPA). Additionally, protected areas are unevenly distributed and unrepresentative of the biodiversity of Antarctica. The Antarctic Treaty Consultative Parties are thus striving to establish a more coherent network of protected areas. In this context, the Otto-von-Gruber-Gebirge was identified as an area highly worthy of protection due to its unique ecosystem including one of the largest snow petrel breeding sites, and relative pristine nature. However, in the process of designation, an update of knowledge, particularly of the population status of snow petrel in the area, was recognized to be needed. This study was aimed at estimating a population census of snow petrel breeding pairs in the Lake Untersee catchment, an important subarea of the potentially protected area. Investigations were severely limited by the remoteness and harsh conditions of the area, enabling only a short fieldwork period with limited resources. Thus, a combination of remote sensing and traditional methods was applied. We conducted a ground survey of a smaller reference area, including locating nest sites and assessing nest site characteristics. Snow petrels usually nest in the cavities of large boulders and we thus classified habitat suitability based on boulder presence. To do so, the study area was remotely surveyed by unpiloted aerial vehicles to gain orthophotomosaics in sufficient resolution to distinguish on-ground conditions for breeding. We then calculated nest site densities for the reference area. We also studied nest site data such as nest cavity depth, orientation, and attendance to gain basic knowledge of the characteristics of the breeding site. Finally, we measured a sample of four live snow petrels to determine which morph was present at the site. We were able to obtain nest site data and to extrapolate it, which produced population numbers of 11,765 breeding pairs for the whole study area. This underpins the size of the breeding site and thereby its importance for the species.

The Antarctic and the surrounding Southern Ocean are currently subject to rapid environmental changes and increasing anthropogenic impacts. Seabird populations often reflect those changes and so act as indicators of environmental variability. Their population trends may provide information on a variety of environmental parameters on the scale of years or decades. We therefore provide long-term data on the cape petrel ( Daption capense ) population from a long-term monitoring program on Fildes Peninsula, South Shetland Islands, Maritime Antarctic, an area of considerable human activity. Our data, covering a period of 36 years, indicate some variability, but no clear trend in the number of breeding pairs between the breeding seasons 1985 and 2006. However, beginning in the 2008 season, the population decreased significantly and reached a minimum in the 2020 season. The mean annual decrease between 2008 and 2020 was 10.6%. We discuss possible causes of this strong negative population trend. Anthropogenic disturbance only affects a few breeding sites in the area and is therefore unable, on its own, to explain the consistent population decline at all the breeding sites studied. We think it more likely that reduced food availability was the main cause of the drastic decline in the cape petrel population.

The use of unmanned aerial vehicles (UAVs) increased during the last decade worldwide and in the pristine wilderness of the Antarctic continent. They are used by scientists from diverse fields, television and film crews, tourists, and station personnel. To protect Antarctic wildlife from potential disturbance, policy makers and national authorities require scientific information on the vulnerability of such species. Our study provides knowledge on the behavioural reaction to UAV overflights of emperor penguins (Aptenodytes forsteri) during crèche and fledge phase. We investigated three main questions: what is the influence of flight height, do two different UAV models (a quadcopter and a fixed-wing UAV) have different effects, and what is the influence of different times during the season. For adult penguins we found no differences between flight heights of 70 m or higher and control situations when flying with the quadcopter. Such a flight height without significant change in reactions in comparison to control couldn’t be found for neither chicks (with both UAV models tested) nor adults during fixed-wing flights. In general, the behavioural reaction to the quadcopter was higher than to the fixed-wing UAV regarding proportions of individuals. The comparison of two times revealed a stronger reaction on the later time (end of December) than on the earlier (mid of November). In general, the reaction was not very intense with only small proportions of individuals changing their behaviour.

The use of UAVs has greatly increased in recent years, worldwide and in the Antarctic. Their use has recently increased even in very remote and pristine regions of the Antarctic. There is, however, very little information on the sensitivity of Antarctic species to such disturbance. In particular, there is nothing on the emperor penguin (Aptenodytes forsteri), a flagship species of the region. We therefore, during November 2019, tested the responses of emperor penguins at the Atka Bay colony (Queen Maud Land). We video recorded the behaviour of adults and chicks during multirotor UAV activity and human approach. There were, in general, only moderate responses with distinct reactions in fewer than 20% of individuals observed. Chicks increased vigilance behaviour during UAV activity but both adults and chicks did so during human approach. We saw the greatest reaction in chicks during vertical UAV approach. Adults showed intermediate reactions to vertical UAV approach but only very few reactions to horizontal flights.

The complete genome sequence of a novel megrivirus of the family Picornaviridae was determined from nucleic acid extracted from a pool of six faecal specimens of Adélie penguins. The samples were collected near Bellingshausen Station, King George Island of the South Shetland Islands, Antarctica. Penguin megrivirus is the first megrivirus with a predicted L protein. It has an L-3-5-4 genome layout, a type IV IRES, and a long 3’ untranslated region of 668 nt.

In recent years Unmanned Aerial Vehicles (UAVs) became a fast-developing technology with manifold fields of application. In the field of wildlife biology, it offers the opportunity to quantify populations, to map the spatial distribution of species and to observe the behavior of animals with no or low disturbance. Moreover, UAV based mapping allows to obtain data from sites which are hardly or not accessible and to cover much larger areas than by traditional ground based methods. The advantages of UAV based mapping are of particular relevance under the harsh conditions of Antarctic fieldwork. Whether certain species qualify for UAV based monitoring depends on their detectability from the distance and the distinctiveness of their characteristics in comparison to other species, which has not been studied for Antarctic species in detail so far. This study aims to evaluate how and under which conditions, particularly flight height, Antarctic flying seabird and seal species are detectable in aerial imagery. A trial was conducted comparing the detection rate of different observers for several Antarctic species in aerial images of different ground sample distances. Descriptions of individual appearance as well as body size dimensions are delivered for all species. For most of the investigated species, monitoring proves to be possible from practical flight heights, while others are still very hard to detect even in low altitudes. A concluding table is given aiming to provide a guide for future surveys on which flight altitudes to chose and how to identify focal study objects.

A recent increase in the use of unmanned aerial vehicles (UAVs)—also known as remotely piloted aircraft (RPA)—in the Antarctic in private, commercial and scientific sectors suggests that operational guidelines are urgently needed. One of the factors inhibiting adoption of such guidelines is the lack of knowledge about the impact of UAVs on wildlife. During the austral summer field season of 2014/15, data were gathered on the behavioural reactions to UAVs of Gentoo (Pygoscelis papua) and Adélie penguins (Pygoscelis adeliae), both resident breeding species on Ardley Island, King George Island, South Shetland Islands. A series of overflights at different altitudes above the nesting penguins were conducted with a small octocopter UAV, and their behaviour was recorded by video. Penguin behaviour altered as a result of the UAV flights, and behavioural reactions were more pronounced when the UAV was flown at lower altitudes. In Adélie penguins, behavioural reactions caused by the UAV were evident at the highest tested altitude of 50 m, while in Gentoo penguins reactions were evident from 30 m downwards. For both species, the reactions increased markedly when the UAV was flown at low altitudes of 10–20 m. Gentoo penguins showed significant reactions when the UAV was launched at distances closer than 20 m. There was some evidence of habituation to the UAV at some altitudes for horizontal flights, but no evidence of habituation in vertical flights.

In the present paper, we compare how the kelp gull, Larus dominicanus, utilizes various nest building materials, particularly vascular plants, bryophytes, lichens and other components, in the Fildes Peninsula area (King George Island) and on the Argentine Islands area. In both areas, nest material primarily consisted of the Antarctic hairgrass (Deschampsia antarctica), bryophytes, lichens, feathers, limpets, and algae. Our study reveals area-specific differences in the utilization of plants for nest building related to local conditions during the nesting season. In the Fildes area, vegetation emerges from under the winter snow cover earlier in the spring, giving the gulls greater choice locally, meaning that the gulls need not resort to long distance material transfer. Here, mosses and lichens dominate in the nest material, likely collected from the nearby vegetation formations. The Antarctic hairgrass in these conditions is mostly found in nests located directly within hairgrass formations. However, on the more southern Argentine Islands, kelp gulls routinely use D. antarctica and some mosses, transferring them from coastal hill tops where snow generally disappears earlier. Here, the gulls appear to be selective still, as they rarely use some mosses, such as Polytrichum strictum, that are abundant near the nesting locations. In the Argentine Islands area, we documented long-range transfer of the Antarctic hairgrass and some other vegetation materials from places of abundance to bare rocks of low islands lacking developed vegetation. This demonstrates the potential of the gulls to serve as dispersal and gene pool exchange agents for the local terrestrial biota in the maritime Antarctic, especially between highly isolated populations from small islands and ice-free areas.

Tardigrada in Antarctic regions are poorly known. The aim of this study was to examine for tardigrades the nests material of the kelp gull (Larus dominicanus Lichtenstein, 1823) in maritime Antarctic and discuss the possible ways of migration and dispersion of tardigrades by birds. We also discuss the influence of bird’s guano on the communities of microscopic invertebrates (mainly tardigrades). In the positive samples (mainly bryophytes and lichens) of seven Larus dominicanus nests, collected on Ardley Island (near Fildes Peninsula) and Argentine Islands, ca. 850 tardigrades and their eggs were found. In total, 13 taxa (including Ramajendas sp.) were identified, and four are new to science: Bryodelphax olszanowskii sp. nov., Diphascon puchalskii sp. nov., D. rudnickii sp. nov. and Hypsibius conwentzii sp. nov.. Bryodelphax olszanowskii sp. nov. differs from known Bryodelphax species in the weglarskae group mainly by having a different ventral plate configuration. Belonging to the pingue group, D. puchalskii sp. nov. differs from other species by some quantitative characters and D. rudnickii sp. nov. by having the first and second macroplacoids situated very close to each other. Hypsibius conwentzii sp. nov. differs from other species of the genus Hypsibius, with two macroplacoids and septulum, by some morphological and morphometric characters. Summarizing, Antarctic tardigrades are a very diverse group, and birds can be responsible for translocation of small invertebrates (including tardigrades) inside of various parts of plants and lichens. They also deposit large amounts of guano, which provides a lot of nutrients for poor tundra ecosystems and support small invertebrate communities.