The study, published in the September issue of Ecology and Society, examined a combination of 15 social and ecological variables -- from tourism and per capita gross domestic product to water stress and political stability.
Then researchers analyzed their correlations with invasive and endangered birds and mammals, which are two indicators of what conservationist Aldo Leopold termed "land sickness," the study said.
Human life expectancy, which is rarely included among indexes that examine human impacts on the environment, surfaced as the key predictor of global invasions and extinctions.
"It's not a random pattern," said lead author Aaron Lotz, a postdoctoral scholar in the Department of Wildlife, Fish and Conservation Biology when the study was conducted. "Out of all this data, that one factor -- human life expectancy -- was the determining factor for endangered and invasive birds and mammals."
The study analyzed data from 100 countries, which included roughly 87 percent of the world's population, 43 percent of global GDP per capita, and covered 74 percent of the Earth's total land area. Additional factors considered were agricultural intensity, rainfall, pesticide regulation, energy efficiency, wilderness protection, latitude, export-import ratio, undernourishment, adult literacy, female participation in government, and total population.
The findings include:
New Zealand, the United States and the Philippines had among the highest percentages of endangered and invasive birds.
New Zealand had the highest percentage of all endangered and invasive species combined, largely due to its lack of native terrestrial mammals. The study said that in the past 700 to 800 years since the country was colonized, it has experienced massive invasion by nonindigenous species, resulting in catastrophic biodiversity loss.
African countries had the lowest percentage of invasive and endangered birds and mammals. These countries have had very little international trade, which limits opportunities for biological invasion.
As GDP per capita -- a standard measure of affluence -- increased in a country, so did the percentage of invasive birds and mammals.
As total biodiversity and total land area increased in a country, so did the percentage of endangered birds. (Biodiversity in this context is not a measure of health but refers to the number of species in an area.)
Lotz said the study's results indicate the need for a better scientific understanding of the complex interactions among humans and their environment.
"Some studies have this view that there's wildlife and then there's us," said Lotz. "But we're part of the ecosystem. We need to start relating humans to the environment in our research and not leave them out of the equation. We need to realize we have a direct link to nature."
The study was co-authored by Craig Allen of the Nebraska Cooperative Fish and Wildlife Research Unit, which provided funding along with the James S. McDonnell Foundation-Studying Complex Systems.About UC Davis
Aaron Lotz | EurekAlert!
Virtual "moonwalk" for science reveals distortions in spatial memory
18.11.2019 | Max-Planck-Institut für Kognitions- und Neurowissenschaften
Autonomous Agriculture in 2045?
15.11.2019 | Fraunhofer-Institut für Experimentelles Software Engineering IESE
Nanooptical traps are a promising building block for quantum technologies. Austrian and German scientists have now removed an important obstacle to their practical use. They were able to show that a special form of mechanical vibration heats trapped particles in a very short time and knocks them out of the trap.
By controlling individual atoms, quantum properties can be investigated and made usable for technological applications. For about ten years, physicists have...
An international team of scientists, including three researchers from New Jersey Institute of Technology (NJIT), has shed new light on one of the central mysteries of solar physics: how energy from the Sun is transferred to the star's upper atmosphere, heating it to 1 million degrees Fahrenheit and higher in some regions, temperatures that are vastly hotter than the Sun's surface.
With new images from NJIT's Big Bear Solar Observatory (BBSO), the researchers have revealed in groundbreaking, granular detail what appears to be a likely...
The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Dresden has succeeded in using Selective Electron Beam Melting (SEBM) to...
Carbon nanotubes (CNTs) are valuable for a wide variety of applications. Made of graphene sheets rolled into tubes 10,000 times smaller than a human hair, CNTs have an exceptional strength-to-mass ratio and excellent thermal and electrical properties. These features make them ideal for a range of applications, including supercapacitors, interconnects, adhesives, particle trapping and structural color.
New research reveals even more potential for CNTs: as a coating, they can both repel and hold water in place, a useful property for applications like printing,...
If you've ever tried to put several really strong, small cube magnets right next to each other on a magnetic board, you'll know that you just can't do it. What happens is that the magnets always arrange themselves in a column sticking out vertically from the magnetic board. Moreover, it's almost impossible to join several rows of these magnets together to form a flat surface. That's because magnets are dipolar. Equal poles repel each other, with the north pole of one magnet always attaching itself to the south pole of another and vice versa. This explains why they form a column with all the magnets aligned the same way.
Now, scientists at ETH Zurich have managed to create magnetic building blocks in the shape of cubes that - for the first time ever - can be joined together to...
15.11.2019 | Event News
15.11.2019 | Event News
05.11.2019 | Event News
19.11.2019 | Life Sciences
19.11.2019 | Physics and Astronomy
19.11.2019 | Health and Medicine