As the world becomes increasingly urbanized, researchers and mayors - from Baltimore to the United Kingdom - recognize the importance of providing an urban habitat that favors biodiversity, which could be the beginning of an urban movement in favor of wild flora and fauna.
A few years ago, in the independent city of Baltimore, Maryland, environmental staff weighed the proposal to plant trees from a local group of citizens. They asked for five trees each of 13 different species, as an arboretum, on the grounds of an elementary school in a neighborhood with a high population density.
It seemed a commendable plan, both for the efforts of the volunteers and for the expected benefits for the environment and the beautification of the place. But someone warned that there was almost no oak on the list, even though the 22 species of oak typical of the area are known for their benefits for flora and fauna. Local foresters, let alone wildlife, could not recognize almost any of the species that had been proposed instead. And to make clear the inconsistency of this logic, the school and the neighborhood were named for oaks. Someone said: "Why do we do this?"
This type of epiphany occurs quite frequently lately in metropolitan areas around the world, as people must cope with the spectacular growth of urbanized areas and the corresponding loss of wild flora and fauna. The part of the planet classified as urban is on its way to tripling from 2000 to 2030 — that is, we are almost halfway there. Meanwhile, 17% of the approximately 800 North American bird species are being reduced, and all of the 20 species on the Audubon Society's list of "Common birds in decline" have lost at least half of their population since 1970
These devastating figures, which are repeated throughout the world, have alarmingly evidenced that it is not enough to plant a million trees in the cities, sing the excellencies of the home gardens or build green roofs and elegant streets. The trees, shrubs and flowers in that seemingly green infrastructure should also benefit birds, butterflies and other animals. They must provide them with a habitat to reproduce, shelter and food. Whenever possible, the habitat should be arranged in corridors where wild flora and fauna can move safely.
Although perhaps it is still too early to be considered an urban movement in favor of wild flora and fauna, initiatives focused on urban biodiversity seem to be becoming fashionable. The US Forest Service, which once joked about the idea that something urban could be wild, now supports an increasingly wider urban forest program. Programs in favor of urban ecology and urban flora and fauna are also proliferating on university campuses. There is the blog "Nature of Cities", which was launched in 2012. Researchers at the University of Virginia have recently announced the emergence of a network of biophilic cities dedicated to integrating nature into urban life, which has Singapore, Oslo and Phoenix among its founding partners. Research has shown that oaks are beneficial for everyone, from caterpillars to songbirds.
And in the independent city of Baltimore, officials now establish that canopy trees, rather than specimen or ornamental trees, must account for 80% of any plantation on city land, and that half of them should be oaks. In an area where previously local nurseries had almost never had stocks of oaks, people sometimes resist, until the city's natural resources manager, Don Outen, explains his logic: research has shown that oaks They are beneficial for everyone, from caterpillars to songbirds. Even fish are favored, because aquatic invertebrates feed on oak leaves from the bottom of streams. At that time, says Outen, the reaction of people is usually "And why haven't we done it before?"
One of the reasons is that researchers have barely thought about what fauna and flora still exist in the city, or how to encourage more. The importance of oaks in the North American states of the Mid-Atlantic, for example, shocked most people in 2009, when Douglas Tallamy, an entomologist at the University of Delaware, published a ranking of trees and shrubs in function of how many species of caterpillars they harbored. (The Royal Horticultural Society has published an analogous list for the United Kingdom.) Unlike oak, which houses 537 species, says Tallamy, the Gingko, a tree typical of the streets of many cities, hosts only three. "But there is the myth that a tree has to come from China to survive in the cities, " he adds. Tallamy likes to point out that a single pair of coal miners in Carolina have to carry between 6, 000 and 9, 000 caterpillars to raise a nest of half a dozen chicks. Black-headed charcoals probably need more. If you love birds, he says, you need caterpillars, and to get the caterpillars you need the right trees. "Not all plants have been created to be the same, " he says. "The natives are surely more beneficial than those that are not, but even among the natives there are differences." For example, although tuliperos are without a doubt majestic, 50 meters high are stingy with wild flora and fauna, since they only house 21 species of caterpillars. Cities concentrate about 20% of avian biodiversity, according to a researcher.
At the National Center for Ecological Analysis and Synthesis (NCEAS), based at the University of California, in Santa Barbara, researchers have begun to complete a much more detailed photograph of what wild flora and fauna mean. Since the study data of wild flora and fauna often ends up geographically dispersed and recorded in different formats, they are making a unified database, with lists of species, abundance, and, in some cases, types of flora habitats. and urban wildlife in 156 cities around the world so far.
The first tests may be more favorable than one might expect, says Madhusudan Kattiel, an ecologist at Fresno State University. Although pigeons, starlings, sparrows and common swallows tend to increase in cities around the world, these four cosmopolitan species do not necessarily indicate that wild flora and fauna have been completely homogenized. Cities also concentrate around 20% of avian biodiversity, according to Katti, but warns that this figure could be upwardly distorted because younger cities tend to have more native birds, so it could be a transitory effect. However, understanding what is happening before species begin to disappear offers the opportunity to carry out interventions and carry out designs in cities so that this does not happen.
A new study published in the journal Landscape and Urban Planning also raises better ways of understanding the combination between urban flora and fauna and habitat. The study uses birds as bioindicators for other types of fauna and flora because they are easier to account for than mammals, mostus and often nocturnal, and because in general they are You are more familiar with people. They are active during the day, brightly colored and singing, says Susannah Lerman, an ornithologist at the University of Massachusetts, and lead author of the new study. So even though most people don't know anything about fauna and flora, they do know something about birds.
Scientists have evaluated not only which trees characterize the neighborhoods, but also how good they are as habitats for birds.
The study proposes a marriage between i-Tree and eBird, two current methods to keep a record of the natural environment. Designed by the US Forest Service, i-Tree is software used by organizations around the world to record tree cover data, from a single tree to entire forests. Its equivalent eBird, from the Cornell Lab of Ornithology, is a system based on a checklist that allows thousands of ornithologists worldwide to record their observations in a central database. The combination of the two allows researchers not only to assess which trees characterize a neighborhood, but also how good they are as a habitat for birds, and what Birds use them.
To demonstrate the usefulness of this methodology, the study co-authors looked at 10 municipalities in the northeastern United States, in which data on trees were available. They aimed to demonstrate that technology can work in a wide variety of communities. So they included municipalities from Moorestown, New Jersey, a dormitory community in Philadelphia with a population of approximately 20, 000, to New York City, with 8.3 million people. They aimed to provide a quick tool for urban planners to assess how a development proposal would affect local fauna and flora, or which neighborhood could benefit more from improvements in the Habitat
Hosting wild fauna and flora in cities does not necessarily require a large investment, according to Lerman. You can bring more birds, he says, just by dividing vast expanses of grass with the right kind of bushes, to create structure and variety. Cutting these grasses less often - every two or three weeks instead of each week - increases the population of native bees and other pollinators. And regarding bird feeders, these do not necessarily increase the population of birds as a whole, but they do present a significant danger: they can become ecological traps., attracting birds to death in a kind of buffet for cats. Just keeping cats indoors, says Lerman, could prevent the loss of billions of birds across the United States every year.
In the United Kingdom, community gardens make a big difference to pollinating insects. In the United Kingdom, adds Mark Goddard, from the University of Leeds, plots, or community gardens, in urban areas make a big difference to pollinating insects, probably because they tend to choose Fruit trees and shrubs and because weed-covered corners tend to be a little more tolerant of insects than private gardens. Concern about the number of pollinator species has also led to the recent proliferation of 60 wild flower meadows in the cities of the United Kingdom, inspired by the extensive meadows planted around the area of the 2012 London Olympics.
The new study by Lerman and his co-authors could have involuntarily found an unlikely source of hope for urban flora and fauna: civic pride and competitive spirit. His study looked at the relative tolerance to wild flora and fauna in 10 cities shows and reduced the differences to a series of figures that indicated how well each city housed nine representative species. While the study expressly avoided making a general ranking of cities, it would be very easy for local supporters to look at the figures and make odious comparisons. For example, among the big cities, Philadelphia was the first in biodiversity, followed by Washington DC Boston was far behind, but ahead of New York, and it surpassed its neighbor from the Hudson River, New Jersey.
There is no formal competition of "green cities" in this country, at least yet. But the "Britain in Bloom" contest, sponsored by the Royal Horticultural Society, increasingly focuses on pollinators and other environmental criteria. Together with a certain municipal rimbombancia, it makes the cities and towns of the United Kingdom strive to plant plantations year after year.
Maybe it's a fantasy to think that something like this could happen in the United States, but imagine: right now, mayors are verbally confronted by meaningless strife between teams with names simply taken from the flora and fauna — Chicago Cubs vs. St. Louis Cardinals, Anaheim Ducks against San Jose Sharks, Atlanta Hawks against Charlotte Bobcats, etc., in what is an entire zoo of rivalries.
If these mayors had to fight for what really matters - "My city has more flora and fauna than yours", "My city has more green spaces than yours", "My city is a better place to live for birds, butterflies and people ”- it would be a competition that would be worth witnessing.
* Richard Coniff is a writer who won the National Magazine Award, whose articles have appeared in the scientific journals Time, Smithsonian, The Atlantic, National Geographic, as well as in other publications. He has written several books, including The Species Seekers: Heroes, Fools, and the Mad Pursuit of Life on Earth. In previous articles for Yale Environment 360, he has written about the price of ecosystem services and about new developments that could help produce food crops that could thrive despite climate changes.
Source: http: //www.ecoportal.net/Temas_Especiales/Habitat_Urbano/Naturaleza_urbana_como_fomentar_la_biodiversidad_en_las_ciudades_de_todo_el_mundo
Urban nature: how to promote biodiversity in cities around the world
