Forest ThreatNet

Volume 9, Issue 1 - January/February 2016

Eastern Threat Center Highlights

A Big-Picture View of the Invasive Plant Problem

Invasive plants increasingly alter the structure and function of our natural environment, and now researchers have determined how far-reaching the problem has become. According to a study conducted by Southern Research Station and university scientists and published in the journal NeoBiota, at least one invasive species is present in 39 percent of forested plots sampled nationwide for invasive plants by the Forest Service Forest Inventory and Analysis (FIA) program. Results are provided for all U.S. regions and reveal that a significant portion of the more than 741 million acres of forested land in the United States has been invaded. The researchers created a U.S. map of invasion-intensity to illustrate the extent of the problem and help inform management actions across the landscape. “For this study, our intention was to let people see how large data sets can be used to understand macro-scale issues and monitoring forest invasion. This broad-scale study gives us a wider perspective that one can’t get from local studies,” says Qinfeng Guo, Center research ecologist and a co-author of the study. Read more in CompassLive...

Left: Researchers found that eastern forests have higher invasion-intensity (a higher percentage of FIA sample sites containing invasive plants of concern in the region or individual states within) than western forests. Image by U.S. Forest Service. Click to enlarge.

Scientists Look to Big Data to Address Local Fire Problems

Burned trees with houses in the background The case of the Bastrop County Complex illustrates the need for a new way of thinking about the issue of wildfire. In September 2011, a year of severe drought, a summer of record-breaking heat, winds from a tropical storm, and a few sparks combined to create the fire, which burned through 34,000 acres of southeastern Texas. Two lives were lost and nearly 1,700 homes were destroyed, with property damages totaling $325 million. Four years later, the memory still fresh in the minds of community members, 575 fire scientists and managers from around the world met nearby in San Antonio during the Association for Fire Ecology’s (AFE) Sixth International Congress, an important knowledge sharing event around the role of fire in land management. Scientists from the Eastern Threat Center and partners from Oak Ridge National Laboratory presented a large body of research during a special session focused on leveraging big data to gain insights toward better solutions for living with fire. “By big data we mean the use of large datasets that previously did not exist or that were too cumbersome to process or disseminate efficiently,” says Center research ecologist Steve Norman, who co-organized the special session along with Center Director Danny C. Lee. “Our session explored how technological developments can help us better address fire management and science questions we’ve long had, but have struggled with, as well as ask important questions we never thought to ask before.” Read more in CompassLive...

Right: In Bastrop State Park, snags, surviving pines, aggressively resprouting holly, and clumped pine regeneration are seen four years after the Bastrop County Complex fire with developed areas in the background. Photo by Steve Norman, U.S. Forest Service.

What Drives the Spread of Invasive Plants?

A forest is invaded by many non-native plants. Scientists often measure the number of invasive plant species to assess invasions, but species richness is just one factor that contributes to the spread of invasive plants. To gain insight into the drivers of invasion, university and Forest Service researchers used Forest Inventory and Analysis data to map and compare invasions in eastern and western forests. They modeled richness and prevalence of invasive species and considered habitat quality and invasion vulnerability as well as the number of propagules (reproductive plant material such as seeds, fruits, and root fragments) produced by invasive plants, known as propagule pressure. Study results, recently published in Diversity and Distributions, reveal that eastern forests are more heavily invaded with varying impacts throughout the region and suggest that propagule pressure and habitat invasibility are key drivers whose contributions to large-scale invasions may differ depending on the stage of invasion. Center research ecologist Qinfeng Guo and North Carolina State University cooperating scientist Kevin Potter are among the study's co-authors. Read more in CompassLive...