Human activity in Antarctica may cause disturbances to its natural environment and organisms. These include, among others, the direct physical alteration of habitat, the introduction of non-native species, and pollution. Here we specifically refer to human disturbance that may cause stress responses in wildlife, particularly on large mammals and birds (seals, penguins, seabirds and cetaceans). Since such situations may incur a stress response from wildlife, negative impacts may be expected in certain circumstances, depending on the strength and frequency of exposure to disturbance. Such human disturbance to Antarctic wildlife can take many forms, ranging from the physical presence of people and their equipment to pedestrian approaches to wildlife, handling of animals for research purposes, and disturbance arising from airplanes, boats and land vehicles. Research, tourist and logistical activities tend to cluster around the coastal ice-free areas of Antarctica, which are often important areas for breeding wildlife.
Human disturbance to Antarctic wildlife can cause declines in breeding success (1, 2, 3), and induce physiological stress (3, 4) which can cause behavioural changes (5, 6), and could be the cause of direct mortality (8). In some cases, wildlife can become accustomed to human activity and be relatively unaffected by it. Some well-studied populations show no major observable changes following disturbance (9). In other cases, human activities have been shown to cause significant disturbance to wildlife (8, 10, 11). Banding of king penguins (Aptenodytes patagonicus) impairs both their survival and reproduction, ultimately affecting their population growth rate (10) and the death of almost 7000 penguins after a stampede on a sub-Antarctic island was argued to be due to a single airplane overpass (8, 11).
An individual animal's response to stress can vary widely as a function of extrinsic factors such as the type of disturbance, its form and its magnitude. Disturbance also varies with intrinsic factors such as the species, colony size and breeding stage, and different individual responses. Few studies (but see 4) have considered all of these factors, making it difficult to draw conclusions or conduct a meta-analysis of the results across the diverse range of studies (12).
Research to date likely underestimates the potential impacts of human disturbance to wildlife as behavioural responses may obscure more subtle and potentially severe physiological responses (13, 14). Most research has focused on the short-term behavioural or physiological impacts of disturbance. Such studies continue to be required, as well as longer-term studies on behavioural and physiological responses to assess the effects of disturbance on populations, although it is exceedingly difficult to link these to long-term population trends. There is comparatively little research on disturbance effects to cetaceans in Antarctica, although studies from the region(15) and elsewhere (16), suggest that impacts are both context and species dependent, and that there are considerable knowledge gaps.
Scientists, managers and policy-makers have long recognized the pressures from human disturbance on Antarctic wildlife (for a review see (12)). Earlier work focussed on aircraft disturbance to wildlife, which culminated in the adoption of the Guidelines for the Operation of Aircraft near Concentrations of Birds in Antarctica at Antarctic Treaty Consultative Meeting XXVII. Many National Antarctic programs have guidelines to minimize disturbance to wildlife. Concerns about the potential disturbance of birds by tourists resulted in the International Association of Antarctica Tour Operators (IAATO) developing the ‘Guidelines for approaching wildlife’ (17).At its 10th meeting (2007), the Committee for Environmental Protection (CEP) commissioned the Scientific Committee on Antarctic Research (SCAR) to provide a report on the current state of knowledge with respect to human disturbance on wildlife. SCAR’s report was provided to CEP XI (2008) (12). The CEP endorsed SCAR's recommendations (CEP XI Report Para 110).
Following the IPCC guidelines on descriptions of uncertainty (18), there is currently high agreement with medium evidence, leading tomedium confidence, that human disturbance can cause significant negative impacts to Antarctic wildlife. However, because of the variability in responses between animals and regions, it is unlikely that a single set of guidelines would be suitable for all regions, for all species and for all situations. The CEP has recognised that minimum approach distance recommendations for different sites requires a precautionary approach and would need to be developed on a case-by-case basis (12, CEP XI Report Para 110). Future work could usefully address the potential synergistic impacts of human disturbance with other factors that influence wildlife such as climate change and non-native species introductions, since disturbance could exacerbate their effects.