US cities host more regionally unique species than previously thought

Citizen science data offers novel comparison of flora and fauna between metropolitan areas

Date:  April 30, 2019

Source:  California Academy of Sciences 

Scientists are analyzing a rare snapshot in time of urban plants and animals. To better understand whether rapidly growing cities are hosting the same species, a concept known as urban homogenization, a team from the California Academy of Sciences analyzed an immense volume of data gathered by citizen scientists during the four-day global City Nature Challenge. The 14 U.S. cities included in the study amassed more than 65,0000 wildlife observations identified to species level through the mobile app iNaturalist. Study findings suggest that despite similarities across cities, urban biodiversity still strongly reflects the species that are native to a region. However, observations of shared "cosmopolitan" species like pigeons, white-tailed deer, and dandelions were more numerous than locally occurring species. The study, published today in the journal PeerJ: Life & Environment, highlights the value of citizen science data in addressing complex questions about rapid changes in urban ecology.

Continued

Cities can serve as a refuge for insect pollinators

Date: October 3, 2016

Source: Plymouth University

Residents living in towns and cities can play a major role in ensuring insect pollinators survive and thrive around them, a team of international scientists has said.

With global bee and butterfly populations in decline, the nature of cities is shifting so that they often contain more diverse and abundant populations of native bees than nearby rural landscapes.

However, urban conservation programmes are largely lagging behind, in that they continue to invest in education and outreach rather than programs designed to achieve high-priority species conservation.

In an essay to be published in Conservation Biology, the academics -- including researchers from the University of Northampton and the University of Plymouth -- said new research into urban ecology is changing how we view the biological value and ecological importance of cities globally.

But in order to ensure this has a recognisable effect on issues such as global food security and ecosystem service provision, policies now need to be better aligned with this newly unfolding image of urban landscapes.

Jeff Ollerton, Professor of Biodiversity at the University of Northampton, and Dr Mick Hanley, Reader in Plant-Animal Interactions at the University of Plymouth, were among the report's authors.

Dr Hanley said: "Previous work conducted in Plymouth has shown that urban gardens in the UK are increasingly being recognised for their potential to maintain or even enhance biodiversity. And by growing a variety of plants from around the world, gardeners can play an important role in ensuring that a range of food sources is available for many different pollinators. This international collaboration demonstrates those theories can also be applied globally, to the potential benefits of people and communities across the world."

Read on 

No junk-food diet: Even in cities, bees find flowers and avoid processed sugars

Date: May 18, 2016

Source: North Carolina State University

New research from North Carolina State University finds that bees in urban areas stick to a flower-nectar diet, steering clear of processed sugars found in soda and other junk food.

"Urban habitats are growing, as is urban beekeeping, and we wanted to see if bee diets in cities are different from those in rural areas," says Clint Penick, a postdoctoral researcher at NC State and lead author of a paper on the study. "For example, we wanted to know if there are even enough flowers in urban areas to support bee populations, or if bees are turning to human sugar sources, like old soda."

To find out, the researchers collected worker honey bees (Apis mellifera) from 39 colonies across rural and urban areas within 30 miles of Raleigh, North Carolina. Twenty-four of the colonies were managed by beekeepers; the remaining 15 colonies were feral.

The researchers then analyzed the carbon isotopes in the bee samples to determine what proportion of their diet came from processed sugars -- like table sugar and corn syrup -- as opposed to flower nectar.

Animals, including bees, incorporate the carbon from food into their bodies. One type of carbon, carbon-13, is associated with grasses such as corn and sugar cane. Researchers can tell how much processed sugar bees consume by measuring each bee's carbon-13 levels. The researchers took a similar approach in a previous study that evaluated the diet of ants in New York City.

Continued ...

Minding the gap: City bats won't fly through bright spaces

Date:

June 4, 2015

Source:

University of Birmingham

Summary:

Researchers have discovered that bats living in a city are less likely to move from tree to tree in brightly lit areas. The bats studied in this experiment emerge in the evening from their roosts, often within residential housing areas, to feed on small insects in gardens, streams and other green spaces. To reach these feeding areas they often "commute" along lines of trees, which are thought to provide protection from predators and high winds.

Read more ...

In the city, rabbits build more densely

Date:

February 18, 2015

Source:

Goethe-Universität Frankfurt am Main

Summary:

European wild rabbits (Oryctolagus cuniculus) not only achieve high population densities in the city, their burrows are also built more densely and on a smaller external scale. As researchers report, small burrow structures with fewer entrances and exits predominate in Frankfurt's inner city. These structures are inhabited by few animals - often only pairs or single wild rabbits. In contrast to this, the structural systems in the rural environs of Frankfurt are substantially larger and are also inhabited by larger social rabbit groups.

Read more ...

Cities Affect Temperatures for Thousands of Miles – via Herp Digest

Jan. 27, 2013 — Even if you live more than 1,000 miles from the nearest large city, it could be affecting your weather.

In a new study that shows the extent to which human activities are influencing the atmosphere, scientists have concluded that the heat generated by everyday activities in metropolitan areas alters the character of the jet stream and other major atmospheric systems. This affects temperatures across thousands of miles, significantly warming some areas and cooling others, according to the study this week in Nature Climate Change.

The extra "waste heat" generated from buildings, cars, and other sources in major Northern Hemisphere urban areas causes winter warming across large areas of northern North America and northern Asia. Temperatures in some remote areas increase by as much as 1 degree Celsius (1.8 degrees Fahrenheit), according to the research by scientists at the Scripps Institution of Oceanography; University of California, San Diego; Florida State University; and the National Center for Atmospheric Research.

At the same time, the changes to atmospheric circulation caused by the waste heat cool areas of Europe by as much as 1 degree C (1.8 degrees F), with much of the temperature decrease occurring in the fall.

The net effect on global mean temperatures is nearly negligible -- an average increase worldwide of just 0.01 degrees C (about 0.02 degrees F). This is because the total human-produced waste heat is only about 0.3 percent of the heat transported across higher latitudes by atmospheric and oceanic circulations.

However, the noticeable impact on regional temperatures may explain why some regions are experiencing more winter warming than projected by climate computer models, the researchers conclude. They suggest that models be adjusted to take the influence of waste heat into account.

"The burning of fossil fuel not only emits greenhouse gases but also directly affects temperatures because of heat that escapes from sources like buildings and cars," says NCAR scientist Aixue Hu, a co-author of the study. "Although much of this waste heat is concentrated in large cities, it can change atmospheric patterns in a way that raises or lowers temperatures across considerable distances."

Distinct from urban heat island effect

The researchers stressed that the effect of waste heat is distinct from the so-called urban heat island effect. Such islands are mainly a function of the heat collected and re-radiated by pavement, buildings, and other urban features, whereas the new study examines the heat produced directly through transportation, heating and cooling units, and other activities.

The study, "Energy consumption and the unexplained winter warming over northern Asia and North America," appeared online January 27. It was funded by the National Science Foundation, NCAR's sponsor, as well as the Department of Energy and the National Oceanic and Atmospheric Administration.

Hu, along with lead author Guang Zhang of Scripps and Ming Cai of Florida State University, analyzed the energy consumption -- from heating buildings to powering vehicles -- that generates waste heat release. The world's total energy consumption in 2006 was equivalent to a constant-use rate of 16 terawatts (1 terawatt, or TW, equals 1 trillion watts). Of that, an average rate of 6.7 TW was consumed in 86 metropolitan areas in the Northern Hemisphere.

Using a computer model of the atmosphere, the authors found that the influence of this waste heat can widen the jet stream.

"What we found is that energy use from multiple urban areas collectively can warm the atmosphere remotely, thousands of miles away from the energy consumption regions," Zhang says. "This is accomplished through atmospheric circulation change."

The release of waste heat is different from energy that is naturally distributed in the atmosphere, the researchers noted. The largest source of heat, solar energy, warms Earth's surface and atmospheric circulations redistribute that energy from one region to another. Human energy consumption distributes energy that had lain dormant and sequestered for millions of years, mostly in the form of oil or coal.

Though the amount of human-generated energy is a small portion of that transported by nature, it is highly concentrated in urban areas. In the Northern Hemisphere, many of those urban areas lie directly under major atmospheric troughs and jet streams.

"The world's most populated and energy-intensive metropolitan areas are along the east and west coasts of the North American and Eurasian continents, underneath the most prominent atmospheric circulation troughs and ridges," Cai says. "The release of this concentrated waste energy causes the noticeable interruption to the normal atmospheric circulation systems above, leading to remote surface temperature changes far away from the regions where waste heat is generated."

City songbirds victims of noise

PUEBLA, Mexico, Nov. 21 (UPI) -- Noise pollution reduces the presence of songbirds in cities and must be considered when analyzing urban biodiversity, Mexican and Spanish researchers say.
A study by the University of the Americas in Mexico and the Basque Institute for Agricultural Research and Development, carried out in the metropolitan area of Puebla-Cholula in Mexico, revealed green zones most affected by noise have fewer bird species, basqueresearch.com reported Monday.

Among the birds better adapted to urban conditions that are being affected by noise pollution are various species of finches, sparrows and thrushes, the researchers said.

The green spaces studied for the frequency of occurrence of 38 songbirds species included urban parks, main squares, university campuses, natural reserves close to the city and even cemeteries.
Squares and urban parks were the noisiest sites among those studied and, in turn, the ones with a small number of species, researchers said.

The next challenge is to discover what levels of noise can be tolerated by each of the species of birds inhabiting urban environments, they said.

Read more: http://www.upi.com/Science_News/2011/11/21/Study-City-songbirds-victims-of-noise/UPI-50401321913546/#ixzz1eWxCt5q1