Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Population pressure shapes urban parks

26.02.2007
A study of 10 Northeastern urban forests shows no sign that there is a common urban park plant complex, but does show that population levels affect both native and nonnative species diversity, according to a Penn State study.

"Less than 1 percent of species were common among all 10 parks," says Robert Loeb, associate professor of biology and forestry at Penn State's DuBois Campus. "This is evidence that common urban park flora does not exist and demonstrates that a diverse flora can be maintained in urban parks."

The parks studied were in Boston, New York, Philadelphia, Baltimore and Washington. All of the parks are more than 100 years old except for the three parks in the Gateway National Recreational Area, New York -- Breezy Point, Jamaica Bay, and the Wildlife Refuge which are all less than 60 years old. The other parks are Middlesex Fells, Boston; Pelham Bay and Van Cortland, The Bronx, New York; Pennypack and Wissahickon Creek, Philadelphia; Oregon Ridge, Baltimore and Rock Creek, Washington, D.C.

Loeb looked at populations of native and nonnative vascular plants in existing surveys of these parks and reported on his work in a recent issue of the Journal of the Torrey Botanical Society.

While all the parks have some fresh water habitat, four – Pelham Bay, Breezy Point, Jamaica Bay and Wildlife Refuge – have salt marsh and seashore environments. Loeb suggests that the long history of plantings in the parks appears to have resulted in greater species similarity among the parks in Baltimore, Washington, D.C. and The Bronx than among the parks in the Gateway National Wildlife Refuge, New York and Bronx, New York.

Dividing the 13 species found in all the parks into native and nonnative, 7 were native and 6 nonnative. The native species included red maple, yellow oxalis, and Virginia creeper. The nonnative species, all considered invasive species in the area, included dandelion, Japanese honeysuckle and tree of heaven. Twenty other species existed in 9 of the 10 parks, 13 native and 7 nonnative.

The Penn State researcher believes that at least some of these species do exist in all 10 parks, but were missed during the surveys. The nonnative species in 9 parks include Norway maple, wild garlic, chicory, ground ivy and mulberry. The native species include yarrow, Indian hemp, milkweed, white ash, sedge, Eastern white pine and Eastern poison ivy.

With less than 2.5 percent of plants occurring in 9 of the 10 parks, Loeb concludes that there is no Eastern Park complex of plants, and that the ratio of native to nonnative species is population dependent.

"Increasing human population is significantly related to decreasing native species and increasing nonnative species," says Loeb. "Higher levels of human disturbances such as trampling, air pollution, or arson have more of a destructive effect on native species. Also, large cities have had more money to purchase planting which traditionally have been nonnative."

The Penn State researcher said, "Urban park managers have implemented vegetation restoration programs with mixed success because of the differing abilities of plants to adapt to the harsh growing conditions found in urban parks."

The list of 1391 species reported for the ten parks provides a source to identify native and non-native species, which are growing in urban parks. "The evidence of species survival under the stresses of human use of urban parks is a critical factor for the selection of species for vegetation restoration projects," says Loeb.

"To help further the work of restoring the natural beauty of urban parks, landscape planting stock suppliers can highlight the capacity of horticultural plants, both native and nonnative species, to survive in the harsh growing conditions of the urban environment" he adds.

"The important city park management goals of recreating pre-European settlement plant communities and past landscape design visions of urban parks can have long-term success when species selections are made with consideration of survival in environments with repeated human disturbances," he says.

Vicki Fong | EurekAlert!
Further information:
http://www.psu.edu

More articles from Studies and Analyses:

nachricht New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg

nachricht Disarray in the brain
18.12.2017 | Universität zu Lübeck

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Gran Chaco: Biodiversity at High Risk

17.01.2018 | Ecology, The Environment and Conservation

Only an atom thick: Physicists succeed in measuring mechanical properties of 2D monolayer materials

17.01.2018 | Physics and Astronomy

Fraunhofer HHI receives AIS Technology Innovation Award 2018 for 3D Human Body Reconstruction

17.01.2018 | Awards Funding

VideoLinks
B2B-VideoLinks
More VideoLinks >>>