A study comparing urban greenspaces with natural areas reveals they鈥檙e contributing a lot more to ecosystems than previously thought.
Could urban parks be offering as much to the health of our ecosystems as natural, pristine reserves do? This is a question a global team of ecologists tackled in a recent study, with the answer coming back 鈥 they were surprised to find 鈥 as yes.
In research published recently in the journal , researchers from UNSW Sydney and multiple institutions described how they compared 56 greenspaces from around the world with nearby natural environments. They were looking specifically at 23 different 鈥榮ervices鈥 the soil and plants from each space offered the surrounding ecosystems such as water retention, carbon capture, nutrient recycling, and pathogen control.
Study lead author Dr David Eldridge from UNSW鈥檚 School of Biological, Earth & Environmental Science says beneath the manicured lawns, mulch and flowerbeds, parks are teaming with life in a very similar way to natural reserves.聽
鈥淲hen we think of parks and ovals we generally think they鈥檙e reclaimed drainage areas, or they鈥檙e old rubbish dumps that have got some topsoil put on them,鈥 he says.
鈥淥ften they are areas that aren鈥檛 much good for anything else, and we say 'Let鈥檚 turn them into a park', or an oval, or a golf course, or something like that. But in fact, when you look at the soils, you find that soils are in good condition. They鈥檙e pretty functionally similar, in most respects to natural systems.鈥
We should think of [greenspaces] as the lungs of the city.
In fact, of the 23 benefits to ecosystem compared, six of them were better in urban greenspaces. These were: available phosphorus, water holding capacity, water respiration, plant cover, arbuscular mycorrhizal fungi (that help plants capture nutrients) and arachnid diversity.
鈥淚t鈥檚 really great to see that greenspace soils were also respiring more,鈥 Dr Eldridge says.
鈥淩espiration is basically the production of CO2. And that means that there are more bugs in the soil that are respiring, they鈥檙e breathing, and that鈥檚 a measure of microbial activity that all life depends on.
鈥淲hen you look at all of these measures of function that we normally think about in soil 鈥 how stable the soil is, how the water is regulated, water infiltration, nutrients, plant symbiosis, decomposition making nutrients available to plants 鈥 mostly, green spaces aren鈥檛 that different to natural systems.鈥
More than social well-being
Normally we think of green urban spaces as land belonging to the public that provides a vital connection with nature and contributes to our social well-being. But the most recent study shows that these spaces are giving us more benefits than we thought.
鈥淓very time we put concrete over soil, or construct pathways through our parks and natural spaces, we鈥檙e making it more and more difficult for water to get into the soil. This gives us more runoff, often taking pollutants out to the sea,鈥 Dr Eldridge says.
鈥淏ut in fact, what these parks are doing is that they鈥檙e providing a place where we can get water into the soil where we can stop that water running off into the sea taking all the litter, plastic and crap with it. I think drainage and water management is an underestimated service that our parks are providing.鈥
Another benefit greenspaces offer are opportunities for people to come into contact with soil microbes.
鈥淭his exposure is really beneficial to human health by promoting effective immunoregulation and reducing allergies,鈥 Dr Eldridge says.
Greenspaces will become more important as our climate gets drier and hotter, providing respite from the sun and a place to hang out. Urban greenspaces are critical for all of us, and should not be underestimated, he says.
鈥淲e should think of them as the lungs of the city.鈥
