Is there a median strip on any of your neighborhood’s roadways with a patch of greenery on it? Chances are there is. You may have hardly noticed it or think that something so small makes very little impact, other than providing a pleasing place to glance at as you drive.
But surprisingly, such small green spaces do have an outsize effect. A recent international study of gardens and parks has found that even a modest roadside shoulder or verge plays an important role in the environment and for our health.
Of course, we already know that we find environments such as city parks, meadows and woodlands that contain lots of different types of animals and plants to be more visually pleasing and interesting, as well as more likely to relieve stress. However, we know much less about seashores and whether the animals there generate the same positive feelings that land-based wildlife does, despite almost three-quarters of the world’s population living within 31 miles of the sea.
New research is showing that seeing a larger number of species on urban coastlines—from marine animals to seaweed—is likely to improve the well-being of local people and visitors. It’s further evidence that biodiversity brings wide-ranging benefits, no matter the size of the space we allow for it.
Microbiomes and mini-green spaces
City parks may be artificial, constructed ecosystems, but they are key players for a healthy environment and for our personal health, according to a study published in the journal Science Advances in July 2021. It’s the first global assessment of soil microbiomes in urban green spaces, and the results revealed that even roadside verges contribute a range of important microbial communities that are critical for sustaining productive ecosystem services, such as filtering pollutants and sequestering carbon dioxide.
For the study, researchers gathered soil samples from different types of urban green spaces and comparable neighboring natural ecosystems in 56 cities from 17 countries across six continents, including Beijing Olympic Park in China; the University of Queensland campus in Brisbane, Australia; Retiro in Madrid, Spain; and the park surrounding Uppsala Castle in Uppsala, Sweden. Human exposure to soil microbes has been shown to be beneficial to human health by promoting effective immunoregulation functions and reducing allergies.
The study found green spaces support many fast-growing microbes that use fertilizers and irrigation water and that can colonize bare soils. These included important fungal root pathogens, such as Fusarium—microorganisms capable of removing nitrogen from sewerage and wastewater—and many bacteria-feeding amoebas. The results mirror a 2014 study in Central Park in New York City, which found there was as much microbial diversity in the city park as there is globally. Urban green spaces from all over the world tend to be very similar. They often have lawns and similar management practices, which homogenize the microbes living in different global cities.
Even highway median strips, which we often think of as being barren, were full of important microbes. Some European cities, such as Bern, Switzerland, have a policy to protect the natural vegetation along footpaths and roadsides. These pathways then become mini-green spaces, linking larger ones.
Since we need lots of different microbes to sustain ecosystem services, we need a variety of landscapes, such as median strips, nature reserves and parks. With 68 percent of the global population set to live in cities by 2050, the study suggests that urban green spaces are critically important for promoting mental and physical well-being.
Biodiversity and beneficial breakwaters
While there is lots of recent evidence showing that land-based environments, such as city parks, meadows and woodlands, have health benefits—including relieving stress—we know much less about seashore species and whether they generate the same positive feelings that land-based wildlife does.
Anecdotal evidence suggests that people may associate marine life, such as seaweeds, with unpleasant, slimy textures and smells, or perceive them to be messy additions to coastlines. So, we might assume that having a greater variety of coastal species may not lead to the same positive effects on our well-being as what is observed on land.
This is important because coastal structures, such as breakwaters and seawalls, are becoming increasingly familiar sights as the climate warms, and they can be homes for many different marine species. Many of them now incorporate measures to conserve or promote biodiversity, such as the Mumbles Sea-Hive Project in Swansea, Wales, in the United Kingdom. But just how these structures might affect the perceptions and well-being of beach visitors isn’t well understood.
To learn how biodiversity may shape peoples’ views, scientists at Swansea University undertook a research study. They recruited 937 participants from Ireland and the United Kingdom. They asked them how appealing, calming and interesting they found images of seawalls with different numbers of seaweed and animal species on them.
The images included between zero and eight different marine species, including different types of anemones, barnacles, limpets, mussels and seaweeds.
To determine whether the type of seawall that animals and seaweeds were growing on changed peoples’ views, images also ranged across three different structure types: from regular-shaped, concrete walls to more irregular, boulder—or “riprap”—sea defenses.
The researchers also used two different viewing scales, from the whole structure to close-ups, to see if different perspectives affected people’s perceptions. The survey, published in the journal People and Nature in May 2022, found that:
• Biologically diverse images on irregular structures were rated most favorably.
• Respondents strongly and positively valued scenes that were seen as diverse, deeming them as more calming and interesting.
• The older seawalls and the ripraps were seen as more “natural” and therefore viewed more positively than the more “artificial,” regular seawalls.
• Diversity and naturalness were rated as the most important qualities in participants’ comments.
• This was especially true with the close-up images, which is how people sometimes view coastal habitats; for example, exploring or looking into rock pools or tide pools.
In summary, say the researchers, people found structures that had more species to be more appealing, calming and interesting to look at. This suggests that high numbers of species provide a range of human benefits, despite occasional negative feelings towards certain species. This occurred because structures were perceived to be more “natural” and have greater “biodiversity” when they were home to a wide variety of sea life.
As public awareness about human impacts on the natural world increases, projects to conserve or enhance biodiversity are becoming more common. This study supports the idea that designing seawalls to support biodiversity not only helps wildlife but can also benefit the lives of people who live by or use our urban coastlines.
Momentous matters on land or sea
We can think of green spaces as arenas for our health. They are associated with less cardiovascular disease, better cognitive functioning in children and the elderly, healthier babies, longer life expectancy, fewer mental health problems and lower premature mortality.
And whether those green spaces are small or large, on land or on shore, they have an inordinate and outsize importance.
Here’s to finding your true places and natural habitats,