Some species, such as peregrine falcons, have higher survival rates or higher reproductive success in cities than in rural areas. Some even prefer urban landscapes. A 2017 analysis of the 529 bird species globally, 66 were found only in urban areas, including not only classic urban birds such as wild pigeons, but also various species native to their regions, such as owls and black-and-pink finches. According to another review, diverse communities of indigenous bee species still exist in cities around the world, and in several cases more diverse and abundant populations of indigenous bees live in cities than in nearby rural landscapes. In Australia, researchers recently identified 39 endangered “last chance” species that survive only in small parts of the city’s habitat, including trees, shrubs, turtles, snails, and even orchids.
For centuries, urbanization has resulted in the removal and shredding of natural vegetation in bulk. After the initial onslaught, a complex mosaic of new habitats emerged consisting of indigenous, alien and invasive plants, dominated by buildings, roads and other impermeable surfaces and polluted by pollution.
Urban ecologists see them as a series of “filters” that make it difficult for many species to survive in cities, especially those with specific habitat requirements. Myla Aronson, an urban ecologist at Rutgers University, pointed out, for example, that so-called lean plants like blueberries and rhododendrons, which need acidic soil, are disappearing from cities. One of the probable causes, she said, is that concrete has increased the alkalinity of urban areas.
Although urbanization continues to pose a significant threat to species and ecosystems, cities abound in a “wonderfully diverse” set of unconventional habitats “that can provide important habitat or resources for domestic biodiversity”. wrote Scientists from the University of Melbourne in their work from 2018 Conservation Biology. They range from remnants of indigenous ecosystems such as forests, wetlands and grasslands, to traditional urban green spaces such as parks, yards and cemeteries, as well as golf courses, urban farms and community gardens. In addition, as cities invest in green infrastructure to mitigate environmental damage, wildlife is increasingly occupying new niches, including green roofs and built-up wetlands, colonizing former brownfield fields and vacant lands. And the positive roles that cities play in nurturing biodiversity “can be strengthened by deliberate design,” the authors write. BioScience an article on the “delusion of biological deserts.”
In recent years, urban ecologists have created a new niche in the field of conservation biology. One fundamental paper, published in 2014, analyzed 110 cities in a range of biogeographical regions with comprehensive inventories of plant life and 54 with complete inventories of birds. According to study, cities have retained most of their natural biodiversity. Aronson, the lead author of the paper, and her colleagues also found that plants and birds in the cities they studied became much smaller, losing 75 percent and 92 percent of their suburban density, respectively.
Another establishment paper on urban conservation biology, published two years later, was written by Australian scientists who found that cities hold 30 percent of the country’s endangered plants and animals, including Carnaby’s black cockatoo, a large, old-fashioned cockatoo that lives only in southwestern Australia. cultivation has fragmented most of its habitat. In fact, they found that cities contain significantly more endangered species per square kilometer than non-urban areas. “Australian cities are important for the conservation of endangered species,” they wrote.
Scientists are described several ways in which urban areas can benefit from regional biodiversity. For example, cities can provide refuge to pressures such as competition or predation that indigenous species face in the surrounding landscape. The higher density of prey in cities has been linked to the success of several urban predators, including Cooper’s hawks, peregrine falcons, hawk hawks, and Mississippi dragons. Cities also serve as stopping places where migratory birds can rest and refuel. Large city parks, such as Highbanks Park in Columbus, Ohio, provide critical habitat for thrushes, ashtrays and other migratory birds.