By Liz Langley
Green spaces within cities can lessen the impact of artificial light on bats, a new study says.
YOU’D THINK HALLOWEEN would be the battiest time of the year, but these winged mammals merit a second annual celebration.
In honor of National Bat Appreciation Day, we’re taking a look at urban bats and how they manage to live among us. (Get the truth behind six bat myths.)
Excessive artificial lighting, also called light pollution, can have a negative effect on many nocturnal animals, for instance by disorienting them or interfering with their reproduction.
But that hasn’t stopped bats from making their homes in cities. For instance, 18 of Germany’s 25 bat species live in Berlin, which is also made up of 20 percent forest.
“Trees provide a lot of benefits for bats,” including roosts, shelter from wind and predators, and better foraging opportunities, says Tanja M. Straka, a researcher at the Leibniz Institute for Zoo and Wildlife Research.
Recent research has shown that plants help themselves grow by releasing volatile organic compounds. These chemicals form a mist of aerosols above the vegetation that blocks some of the direct light but enhances diffuse light. This boosts the solar radiation reaching the forest understory and increases growth.
Alexandru Rap from the University of Leeds, UK, and colleagues assessed the impact of plant volatiles on primary productivity by using atmospheric and vegetation models along with measurements of aerosols and plant productivity. Their findings, published in Nature Geoscience, show that globally plant volatiles boost vegetation productivity by around 1.23 Pg of carbon per year — equivalent to around 10% of the world’s fossil fuel carbon emissions.
“Amazingly we found that by emitting volatile gases, forests are altering the Earth’s atmosphere in a way which benefits the forests themselves,” says Rap. “While emitting volatile gases costs a great deal of energy, we found that the forests get back more than twice as much benefit through the effect the increased diffuse light has on their photosynthesis.”
Collecting dust isn’t usually considered a good thing.
But dust from as close as California’s Central Valley and as far away as Asia’s Gobi Desert provides nutrients, especially phosphorus, to vegetation in the Sierra Nevada Mountains, a team of scientists has found. Their study, published in the journal Nature Communications, highlights the importance of dust and the phosphorus it carries in sustaining plant life.
The researchers examined soil samples from four sites at the National Science Foundation (NSF) Southern Sierra Critical Zone Observatory (SSCZO) in the Sierra National Forest, at elevations from 1,300 feet to 8,800 feet. The SSCZO is part of a network of nine NSF Critical Zone Observatories across the United States and the U.S. territory of Puerto Rico.
The critical zone — Earth’s living environment — is the region between the top of the forest canopy and the base of weathered rock.
The zone consists of multiple interactive processes, including the water cycle, the breakdown of rocks and the formation of soil, the evolution of rivers and valleys, the patterns of vegetation, and the form and function of the Earth. Scientists at all nine CZO sites study this zone and its response to climate and land use changes.
“The CZO network was set up to carry out research that integrates physical, geochemical and biological measurements from the subsurface through the land surface, giving us the ability to improve management of these rapidly changing landscapes,” said University of California, Merced scientist Roger Bales, who leads the SSCZO.
The research team — including geochemists, a geomorphologist, ecosystem ecologists and microbial ecologists from UC Merced, UC Riverside, the University of Michigan and University of Wyoming — worked to quantify the importance of transoceanic and regional dust as a nutrient source to Sierra Nevada ecosystems. They used household items — for example, Bundt pans filled with marbles attached to wooden posts — to capture dust. They also studied microbes hitchhiking on dust particles to pinpoint the dust’s origins.
“Dust provides important inputs of phosphorus to Sierra Nevada ecosystems,” said UC Merced scientist Stephen Hart, a co-author of the paper. “The dust brings critical nutrients [such as phosphorus] for maintaining plant productivity in these mountain environments. Dust inputs may increase as land use in the Central Valley intensifies and as the climate changes in the future.”