comment COVID-19 lockdown allows researchers to quantify the efects of human activity on wildlife Reduced human mobility during the pandemic will reveal critical aspects of our impact on animals, providing important guidance on how best to share space on this crowded planet. Christian Rutz, Matthias-Claudio Loretto, Amanda E. Bates, Sarah C. Davidson, Carlos M. Duarte, Walter Jetz, Mark Johnson, Akiko Kato, Roland Kays, Thomas Mueller, Richard B. Primack, Yan Ropert-Coudert, Marlee A. Tucker, Martin Wikelski and Francesca Cagnacci ver the past few months, many Unprecedented circumstances countries around the world went Box 1 | Introducing ‘anthropause’ As expanding human populations Ointo lockdown to control the are transforming environments at spread of COVID-19. Brought about by the We noticed that people started referring to unprecedented rates, understanding the most tragic circumstances, this period of the lockdown period as the ‘Great Pause’, linkages between human and animal unusually reduced human mobility — which but felt that a more precise term would behaviour is of critical importance. It is we suggest be coined ‘anthropause’ (see be helpful. We propose ‘anthropause’ to key to preserving global biodiversity, to Box 1) — may provide important insights refer specifcally to a considerable global maintaining the integrity of ecosystems, into human–wildlife interactions in the slowing of modern human activities, and to predicting global zoonoses and twenty-first century. Anecdotal observations notably travel. We are aware that the environmental change5. This knowledge is indicate that many animal species are correct prefx is ‘anthropo-’ (for ‘human’) not only worth billions of dollars, but it is enjoying the newly afforded peace and quiet, but opted for the shortened form, which also vital for shaping a sustainable future. while others, surprisingly, seem to have is easier to remember and use, and where So far, however, researchers have had come under increased pressure. the missing ‘po’ is still echoed in the to rely predominantly on purely Here, we highlight how the pronunciation of ‘pause’ (pɔːz). observational approaches. international research community can Scientists have long sought to quantify use these extraordinary circumstances how humans impact various aspects of to gain unprecedented mechanistic following reductions in vessel traffic and animal biology, such as population levels, insight into how human activity affects noise-pollution levels1. reproductive and mortality rates, movement wildlife. We outline urgent steps different But for some species, the pandemic may and activity patterns, foraging behaviour, stakeholder groups need to take to ensure have created new challenges. For example, and stress responses1,6–8. Studies usually this opportunity is not missed, and various urban-dwelling animals, like rats, employ one of two main approaches — introduce global collaborative research gulls or monkeys, have become so reliant on spatial comparisons or temporal analyses. initiatives that are currently forming food discarded or provided by humans that The first involves comparing a species’ to facilitate coordination. Scientific they may struggle to make ends meet under biology across areas that differ in human knowledge gained during this devastating current conditions. Interestingly, in some activity. Such differences occur, for example, crisis will allow us to develop innovative countries where lockdowns allow outdoor along urban gradients, with increasing strategies for sharing space on this exercise, humans are flocking to green distance from coastlines, or between increasingly crowded planet, with benefits spaces in or near metropolitan areas (see protected and unprotected areas. The second for both wildlife and humans. Fig. 1), potentially disturbing resident approach documents how animals respond wildlife2. At the same time, reduced to temporal changes in human activity in Possible efects on wildlife human presence in more remote areas may a given locality, which may be short-term6 Social media abound with posts sharing potentially expose endangered species, such (for example, holiday periods, or natural surprising wildlife encounters during as rhinos or raptors, to increased risk of or human-made disasters) or longer-term lockdown. As we gaze out of our windows, poaching or persecution3. Finally, concerns (for example, changes in protection status, or relish a brief walk in the park, nature have been raised that, in low-income or land- or seascape modification through appears to have changed, especially in urban countries, economic hardship may force construction). environments. There not only seem to be increased exploitation of natural resources4. The reduction in human mobility on more animals than usual, but there are At present, it is impossible to say which land and at sea during the anthropause is also some unexpected visitors. People have observations have been hyped by social unparalleled in recent history9,10. Lockdown reported sightings of pumas in downtown media, and which expert predictions about effects have been drastic, sudden, and Santiago, Chile, of dolphins in untypically global animal responses will hold true. But widespread. Countries have also responded calm waters in the harbour of Trieste, what is clear is that humans and wildlife in broadly similar ways across large parts of Italy, and of jackals in broad daylight in have become more interdependent than ever the world, presenting invaluable replicates urban parks in Tel Aviv, Israel. Hidden before, and that now is the time to study of this perturbation. So, how exactly can from view, animals may also start roaming this complex relationship. A quantitative we make the most of these exceptional more freely across the world’s oceans, scientific investigation is urgently needed. circumstances? NATURE ECOLOGY & EVOLUTION | www.nature.com/natecolevol comment While every field study has value in its own right, the pandemic affords an opportunity to build a global picture of animal responses by pooling large numbers of datasets. Such collaborative projects can integrate the spatial and temporal approaches outlined above, in an attempt to uncover causal relationships. Aspects of animals’ biology can be compared Humans per km2 across sites that vary in COVID-19-related 0 26 to 250 1 251 to 1,000 restrictions and resultant changes in human 2 to 5 >1,000 mobility, and across different time periods, 6 to 25 spanning from before until after changes Subsample of bio-logging studies occurred. Taking into account additional Avian data from unaffected ‘control’ sites11, such Marine as particularly remote or inaccessible areas, Terrestrial researchers will be able to examine if, and how, animals responded to reductions in human activity. Baseline data from similar time periods in prior years, and from years following the COVID-19 pandemic, will considerably strengthen inferences, helping to disentangle anthropause effects from natural seasonal variation in animal biology. Finally, we wish to share a very important sentiment. While this is no doubt a valuable research opportunity, it is one that has only come about through tragic circumstances. % change in humans visiting parks Scientists who prepare to study lockdown No data 1 to 25 effects on wildlife, and on the environment –100 to –76 26 to 50 more generally, should be sensitive to –75 to –51 51 to 75 the immense human suffering caused by –50 to –26 76 to 100 –25 to –1 >100 COVID-19 and use appropriate language to 0 describe their work. Mobilizing the community Fig. 1 | Illustrating the research potential of the recently launched COVID-19 Bio-Logging Initiative. Top: locations of a subsample of active animal tracking (‘bio-logging’) studies superimposed on human General insights about animal responses — population density. Data sources: 801 publicly visible animal tracking studies from the Movebank across different species, geographic regions, research platform (www.movebank.org) that are likely to contain data overlapping with the COVID-19 ecosystems, and levels of human activity period (data extracted 18 May 2020). ‘Marine’ includes seabirds and other marine species, ‘avian’ — will only be possible if researchers pool refers to all other bird species, and ‘terrestrial’ are non-avian species living mostly on land. Population their data and expertise. Several initiatives density data sourced from ref. 15 (data accessed 15 May 2020). Bottom: median percentage of change are busy preparing global-scale collaborative based on daily values (with reference to the data provider’s default baseline from the five-week period research projects to achieve exactly this. between 3 January and 6 February 2020) in visits to places like local parks, national parks, public One of them — the COVID-19 beaches, marinas, dog parks, plazas and public gardens for the month of April 2020. Data are plotted Bio-Logging Initiative (www.bio-logging. for 900 subregions within 131 countries (note that for 1.6% of the subregions fewer than 5 daily values net) — recently formed under the umbrella were available for April 2020). This information should be interpreted cautiously, and is shown here of the International Bio-Logging Society, in merely to provide a preliminary, coarse-scale illustration of some recent changes in human mobility; collaboration with the Movebank research scientific analyses will require higher-resolution, calibrated data. Data sourced from ref. 16 (data platform, and the Max Planck–Yale Center