A team of scientists has discovered that human-introduced, invasive species of plants can have positive ecological effects. Toms Carlo, an assistant professor of biology at Penn State University, and Jason Gleditsch, a graduate student in the Department of Biology, have studied how invasive fruiting plants affect ecosystems and how those effects, contrary to prevailing ideas, sometimes can be beneficial to an ecological community. The team's research, which will be published in the journal Diversity and Distributions, is expected to affect the way environmental resource managers respond to ecosystem maintenance.
"Among conservation biologists, ecologists, and managers, the default approach is to try to eliminate and root out non-native, invasive shrubs -- anything that seems to change an ecosystem," Carlo said. "The fundamental goal is to return a natural area to its original, pristine state, with the native species occupying the dominant position in the community. But the problem is that most native communities already have been changed beyond recognition by humans, and many native species are now rare." Carlo explained that his team wanted to test whether certain well-established, invasive fruiting species have negative or positive effects on bird and fruiting-plant communities. "We wondered: Are we sometimes doing more harm than good when we eradicate plants that, despite being introduced recently, have formed positive relationships with native animals?" To be considered invasive, a species of plant must have been introduced by humans, and it must be dominant numerically in the new environment.
To test the impact of an invasive fruiting-plant species on native bird communities, Carlo and Gleditsch sectioned off an area of central Pennsylvania known as the Happy Valley region, where honeysuckle -- a non-native fruiting plant that is considered invasive -- grows in abundance. They then assessed the abundance of bird species and fruit
|Contact: Barbara Kennedy|