This greatly increases the risk that a new wave of invasives will overrun native ecosystems in the way kudzu, Oriental bittersweet and purple loosestrife have in the past, members of the international team say.
The kudzu invasion of the past few decades saw whole forests overgrown in the Southeast, along with hedgerows, power lines and even houses. In wetlands across the nation, purple loosestrife is crowding out native marsh plants, and Oriental bittersweet, if left unchecked, shades and chokes out native trees, bushes and shrubs along streams, forest and field edges.
Bradley and colleagues recommend that U.S. authorities adopt proactive management practices, in particular pre-emptive screening of nursery stock before new plants are imported, to prevent such an explosion of new invasives. Their conclusions appear in an early online edition of the Feb. 1 issue of Frontiers in Ecology and the Environment.
As the UMass Amherst environmental conservationist and lead author explains, the U.S. Department of Agriculture (USDA) has proposed the Not Authorized Pending Pest Risk Analysis (NAPPRA) rule to regulate the industry. The rule would require importers to notify the USDA of proposed imports. USDA scientists would then conduct a timely risk assessment and issue a recommendation to allow or curtail the import.
“Our study identifies climate change as a risk, which combined with other factors is likely to increase demand for imported heat- and drought-tolerant plants, but this emerging threat is one that policy can effectively address,” Bradley says. “The USDA has tools to reduce import risk and we advocate that now is the time put them in place. Pre-import screening has been tested in Australia for about 10 years now and it’s not foolproof, but it seems to have done a good job of separating the really bad import ideas from more benign introductions.”
Not all imported plants become invasive, but those that do can become a significant threat to native plants and we should not be complacent about the current situation, she says. About 60 percent of plants now considered invasive were introduced deliberately through the plant trade. The other 40 percent are human-related accidental introductions such as seeds stuck in cargo or shipping containers. Only a tiny fraction of non-native introductions are from natural causes such as blowing in with a hurricane, Bradley says.
She and colleagues point out that rising average temperatures in certain regions of the U.S. are already shifting plant hardiness zones northward and the trend is expected to continue globally. Their study suggests that with the earlier onset of spring, warmer winters, economic globalization and increased trade with emerging economies in Asia and Africa, we may face a significant new wave of invasive plant introductions.
For this analysis of the intersection of global trade and climate change, the ecologists used import values from 1989 to 2010 to identify emerging trade partners, because earlier studies had established a clear link between increased trade and the number of invasive species. They found 42 emerging trade partners poised to supply new nursery plant varieties including Thailand, Egypt, Saudi Arabia, Ecuador, Argentina and several in equatorial Africa.
The rate of introduction is steepest in the early stages of new trade relationships, the authors say. “Unfortunately, increasing the variety and availability of non-native, drought-tolerant species could also increase the probability of introducing species capable of invading dryland regions.” Bradley adds, “In the desert Southwest this has already been happening with xeriscaping, which is becoming more and more popular.” Xeriscaping refers to gardening with low or no need for watering.
Bradley and colleagues’ work focuses on introduction, the first of three stages of invasion, because “stopping invasions before they start is the most effective way of preventing widespread ecological and economic impacts,” she says. “Globalization has accelerated the rate of introduction from a few species at the first colonization of North America to now, when we probably see thousands of new species each year. All we need is another kudzu to have a big impact.”
This work was supported by the National Science Foundation's National Center for Ecological Analysis and Synthesis.
Bethany Bradley | Newswise Science News
Urban growth causes more biodiversity loss outside of cities
10.12.2019 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Wie ganze Ökosysteme langfristig auf die Erderwärmung reagieren
10.12.2019 | Universität Wien
In a joint experimental and theoretical work performed at the Heidelberg Max Planck Institute for Nuclear Physics, an international team of physicists detected for the first time an orbital crossing in the highly charged ion Pr⁹⁺. Optical spectra were recorded employing an electron beam ion trap and analysed with the aid of atomic structure calculations. A proposed nHz-wide transition has been identified and its energy was determined with high precision. Theory predicts a very high sensitivity to new physics and extremely low susceptibility to external perturbations for this “clock line” making it a unique candidate for proposed precision studies.
Laser spectroscopy of neutral atoms and singly charged ions has reached astonishing precision by merit of a chain of technological advances during the past...
The ability to investigate the dynamics of single particle at the nano-scale and femtosecond level remained an unfathomed dream for years. It was not until the dawn of the 21st century that nanotechnology and femtoscience gradually merged together and the first ultrafast microscopy of individual quantum dots (QDs) and molecules was accomplished.
Ultrafast microscopy studies entirely rely on detecting nanoparticles or single molecules with luminescence techniques, which require efficient emitters to...
Graphene, a two-dimensional structure made of carbon, is a material with excellent mechanical, electronic and optical properties. However, it did not seem suitable for magnetic applications. Together with international partners, Empa researchers have now succeeded in synthesizing a unique nanographene predicted in the 1970s, which conclusively demonstrates that carbon in very specific forms has magnetic properties that could permit future spintronic applications. The results have just been published in the renowned journal Nature Nanotechnology.
Depending on the shape and orientation of their edges, graphene nanostructures (also known as nanographenes) can have very different properties – for example,...
Using a clever technique that causes unruly crystals of iron selenide to snap into alignment, Rice University physicists have drawn a detailed map that reveals...
University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making
In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...
03.12.2019 | Event News
15.11.2019 | Event News
15.11.2019 | Event News
11.12.2019 | Life Sciences
11.12.2019 | Health and Medicine
11.12.2019 | Earth Sciences