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The virus, natural areas & urban people

United Nations Secretary General Antonio Guterres calls the COVID-19 pandemic "the most challenging crisis we have faced since the Second World War." Public health experts call it the worst pandemic since the H1N1 pandemic of 1918-1919.   

On 8 April 2020, IUCN issued a Statement on the COVID-19 Pandemic. It focuses on sources of zöonotic diseases, diseases caused by a pathogen that has jumped from non-human animals to humans. COVID-19 is caused by a newly discovered coronavirus called SARS-CoV-2 that is found in bats; the intermediate host may be pangolins. As drivers of zöonotic diseases, the statement mentions the illegal wildlife trade and land-use change, including deforestation and habitat fragmentation. In land-use change, the key factor is disturbance of the equilibrium between certain hosts and parasites. 

The flagship publication of the IUCN WCPA Urban Conservation Strategies Specialist Group, Urban Protected Areas: Profiles and Best Practice Guidelines, covers land-use change in the form of urbanization in several of its guidelines, and a separate guideline (printed below) deals with emerging infectious diseases.  

Over the longer term, our specialist group needs to work with others on these issues. Right now, however, we must focus our attention on a problem that isn't mentioned in these guidelines because it hasn't arisen on a global scale for over a century: the need to close urban nature reserves and trails to stop the rapid spread of a fatal disease, and the issues involved in reopening such places. 

Closing & reopening urban protected areas & trails


Beginning in March of 2020, people in many parts of the world were under stay-at-home orders or more limited travel restrictions to stop the spread of the coronavirus SARS-CoV-2. Along with schools, shops, and many other kinds of places, protected areas were temporarily closed to the public. This has been done in different ways, as has reopening protected areas, but the basic issues involved tend to be the same.   

To provide some background and start a discussion, here are excerpts from an article Specialist Group Chair Ted Trzyna wrote from the perspective of where he lives, metropolitan Los Angeles, in the U.S. state of California. Los Angeles is one of the 15 places profiled in our IUCN publication Urban Protected Areas. These are his personal views, not necessarily endorsed by IUCN.

It’s too soon to reopen most of our mountain parks and trails 

Ted Trzyna, 12 May 2020 

Note: Many of these parks and trails were reopened in late May 2020, but the issues remain.

On weekends in normal times, Southern California’s mountain parks and trails are full of hikers and picnickers, but for over a month now most of these places have been closed to stop the spread of COVID-19. Staff, as well as visitors, are at risk. ... 

Pressure to reopen these places is increasing. When can our mountain parks and trails be reopened safely, and on what basis?   

In sorting out public policy issues, it helps to start out by defining terms. In this case, “parks” is a word that is easily misunderstood. On one hand it refers to conventional city parks with lawns, flower gardens, playgrounds, and sports fields. On the other hand, it is used for natural and wilder areas such as national parks; officially these are called “protected areas,” but “nature reserves” serves just as well.


This is a crucial distinction when considering how the coronavirus that causes COVID-19 spreads in public spaces. To control it, the U.S. Centers for Disease Control and Prevention specifies social distancing along with wearing a cloth face cover: “Stay at least 6 feet [2 m] from other people; do not gather in groups; stay out of crowded places and avoid mass gatherings.” 

But activity is a lot harder to monitor in nature reserves than in conventional city parks, where visitors are more visible and can be discouraged from gathering. 

Joe Edmiston,* longtime executive director of the Santa Monica Mountains Conservancy, a state agency responsible for some of the most popular nature reserves in Southern California, told me, “People don’t go to these places to distance themselves; they’re nothing but gathering spots. On our narrow trails, I’ve often seen groups of hikers passing each other within sneezing distance. What we’re working against here is the notion of the freedom of the hills.” 

Managers of heavily visited public lands are looking at introducing one-way trails, mandatory distancing and face covering, and even limiting the number of people allowed on certain trails. 

Many of the world’s gems of urban nature are closed because of stay-at-home orders. Examples are Table Mountain National Park in Cape Town, South Africa, which usually has around 4 million visits a year; and Brazil’s Tijuca National Park, the forested backdrop to Rio de Janeiro. How can such places be reopened safely to protect both locals and foreign visitors? 


Hong Kong is an exception and a lesson: It has kept its extensive nature reserves and trails open to the public during the COVID-19 emergency. In one of the world’s most densely populated cities, a remarkable 40 percent of the land is protected in natural Country Parks.

My friend Fook Yee Wong,* a former director of the parks, wrote to me about the current situation: “In Hong Kong people consider natural places safer, healthier, and more hygienic than urban areas.” Social distancing is required, but “this will depend very much on visitors’ self-regulation and discipline.” I can attest to such behavior because in better times I’ve observed it as Fook Yee showed me around many of the Country Parks. Another thing: Hong Kong’s leaders responded quickly to COVID-19 because they had recent experience with another pandemic, the 2003 SARS outbreak, and knew the parks would be a necessary escape from crowded neighborhoods. ... 


Aside from the benefits of exercise, spending time in nature improves physical and mental health; plenty of scientific evidence backs this up. However, in the time of the virus, what is gained by spending time in nature needs to be weighed against the very real risk of exposure leading to serious illness and death. I’ve been surprised to find some public health professionals arguing for reopening parks without specifying what kinds of parks or seriously considering all the risks. One article is headed, “If we can safely distance at the grocery store, surely we can do the same at parks.” This may work in Hong Kong, but will it work on our mountain trails? For many of us the first whiff of chaparral or pine needles seems to give us permission to ignore the rules.  

To go back to the question I asked at the top: When can our mountain parks and trails be reopened safely? For most of them, it’s too soon, but planning and public discussion need to start right away and include all the agencies responsible.         

Decisions about protecting people from the coronavirus are often described as being about science versus politics, which is a way of saying science has the answers if only politicians would listen. Science is essential to understanding COVID-19, but it can’t tell us what is right or wrong. 

What must guide us here are basic human values represented by two powerful and widely accepted ideas. One is the medical doctrine, “First, do no harm,” sometimes recast as “First, do no harm; then try to prevent it.” The other is the precautionary principle, which can be summed up as “Better safe than sorry,” or a little more formally as “Scientific certainty is not required before taking preventive measures.”

In deciding when and how to reopen our mountain parks and trails, these ideas are a good place to start. 

*Both Edmiston and Wong are Deputy Chairs of the Specialist Group. 


Observe wildlife rules ... but with people! [U.S. National Park Service]

Emerging infectious diseases & protected areas

From Urban Protected Areas: Profiles and best practice guidelines. Best Practice Protected Area Guidelines Series No. 22. Gland: IUCN, 2015. Pages 65, 67.

Guideline 9. Reduce human-wildlife interaction and conflict; keep aware of emerging infectious diseases

To reduce hazards resulting from the interaction between wildlife and people in and near their parks, managers of urban protected areas should: …

Be aware of the potential danger to people of emerging infectious diseases in wildlife and the natural environment; and

• Educate decision-makers about the value of keeping habitat as natural as possible to control such emerging infectious diseases. …

9.6 Emerging infectious diseases

Infectious diseases that have newly appeared in a human population or have been known for some time but are rapidly increasing in incidence or geographic range, are called ‘emerging infectious diseases’. Most of them are zöonotic, that is, they are transmitted between other animals and humans. Examples are malaria, dengue, yellow fever, plague and leishmaniasis.

Degradation of wildlife habitat, increased edge effect and increased human-wildlife interaction are all major drivers of zöonotic diseases, as is human interaction with domestic and farm animals. The key factor is disturbance of the equilibrium between certain hosts and parasites. A good illustration is Lyme disease, first described in 1977 in the northeastern United States, which has since been found in other parts of North America, as well as parts of Europe, Asia and Australia. Lyme disease is caused by a bacterium, Borrelia burgdorferi, which is transmitted to humans by bites from ticks [above: deer tick, Ixodes scapularis]. If it is treated early, the infection is eliminated by antibiotics. If untreated, it can lead to meningitis, heart disorders and severe arthritis. In eastern North America, the white-footed mouse (Peromyscys leucopus) is an important reservoir of the Lyme disease pathogen. In intact habitats, mouse populations are controlled by owls, hawks, snakes, foxes, weasels and other species. In fragmented or degraded habitats, such predators are fewer in number or may not exist. 

Globally, the generally warmer and wetter conditions resulting from climate change, combined with habitat changes, are expected to encourage the conditions in which the spread of infectious diseases (including entirely new diseases) occurs, thus increasing the danger of transmission to humans. 

Urban protected areas have a dual role here. When they protect natural ecosystems that are more or less intact, they tend to keep the ecology of microorganisms in balance. But when they are degraded, such as around roads, along boundaries and in heavily visited locations, they may facilitate the interaction among pathogens, vectors and hosts, and thus create the conditions in which disease is spread. These are good reasons for maintaining urban protected areas in as natural a state as possible.

The links between loss of wildlife habitat and emerging infectious diseases are receiving increased attention from scientific researchers and public health professionals. Managers of protected areas should keep abreast of what is happening in their regions and cooperate with those involved. They should also educate governmental decision-makers about the value of keeping wildlife habitat as natural as possible so as to control emerging infectious diseases—in addition to many other reasons. 

Deer tick, Ixodes

Deer tick, Ixodes scapularis