ASU research plays key role in lower Salt River restoration

Recently published study uses drone data to identify and 3D map invasive vegetation species with unprecedented detail

June 2, 2021

Along the lower banks of the Salt River, dense thickets of tall, weedlike invasive saltcedar and giant reed threaten native vegetation vital to preserving the biodiversity of one of the few remaining low elevation desert riparian vegetation communities in the state.

Accurately mapping species level vegetation is an essential step in managing invasion risk, guiding remediation efforts and intervention strategies and ultimately understanding what processes are facilitating invasive species growth or expansion.  the Salt River running along the base of a mountainous terrain The Salt River in Arizona. Photo courtesy of Depositphotos.

However, mapping large areas of vegetation manually from the ground is both labor- and time-intensive, and using traditional satellite platform imagery is difficult due to its coarse spatial resolution. Unmanned aircraft systems (UAS), or drones, provide a largely new opportunity for high-resolution remote sensing and capturing this critical data. 

Recently published research led by Arizona State University Master of Advanced Study in Geographic Information Systems (MAS-GIS) alumnus Arnold Chi Kedia and co-authored by Amy Frazier, assistant professor in the School of Geographical Sciences and Urban Planning, uses drone-sensed data to spatially map vegetation along the lower Salt River and distinguish native and non-native vegetation species.

In their paper, “An Integrated Spectral-Structural Workflow for Invasive Vegetation Mapping in an Arid Region Using Drones,” published in Drones, the researchers develop a new mapping process combining structural data with spectral data to three-dimensionally model the lower Salt River landscape with precise resolution within 3-5 centimeters.

“Not only do we have the spectral reflectance, how different vegetation species are reflecting light, but we also have their structure in terms of how tall they are or how voluminous they are,” said Frazier, who also is the associate director of ASU’s Geospatial Research and Solutions. “Both of those data streams came from drone data, and the combination of adding the structure actually made our accuracy for figuring out where things were much higher.” 

The researchers found that including spectral and three-dimensional structural layers in their classification, as opposed to just using spectral data, improved overall vegetation species identification accuracy from 80% to 93%. 

“Using terrain data and canopy height were actually very important characteristics to identify these plant species,” Kedia said. “Most research just uses spectral data, but structural data controls how plant species are distributed in their natural habitat. This is what makes our paper unique; this method of combining both structural and spectral information has not been used before.”

The three structural layers, including (a) digital terrain model (DTM), (b) canopy height model (CHM) and (c) flow accumulation.

With a more accurate and detailed picture of what’s happening, land managers can use the information to better develop strategies to monitor and control invasive vegetation in the lower Salt River.  

The research was conducted in collaboration with local drone company Green Drone AZ, and the data from the study is now being used in the continuing Lower Salt River Restoration Project

Additional co-authors of the research include ASU MAS-GIS graduates Brandi Kapos and Songmei Liao, and Green Drone AZ team members Jacob Draper, Justin Eddinger and Christopher Updike.

David Rozul

Media Relations Officer, Media Relations and Strategic Communications


Improving a virus’s cancer-killing potency

June 2, 2021

In recent years, an unusual new domain in cancer research has opened up. The idea is to use infectious pathogens to attack and kill cancerous cells. So-called oncolytic viruses, in particular, have shown great promise for targeting cancer cells while leaving normal, healthy cells intact.

In new research, Rahman Masmudur and his colleagues describe a method for improving the effectiveness of a powerful oncolytic virus known as myxoma virus.  ASU researcher Rahman Masmudur smiling in front of some cacti, wearing glasses and a button down shirt Rahman Masmudur is a researcher with the Biodesign Center for Immunotherapy, Vaccines and Virotherapy at ASU. Download Full Image

A member of the pox family of viruses, myxoma virus has some highly unusual properties. It has long been recognized as lethal to European rabbits, producing an invariably fatal disease known as myxomatosis, while appearing harmless to other species, including humans. Remarkably, myxoma virus has more recently been shown to display an insatiable appetite for cancer cells, attacking and killing them. 

“We are trying to improve myxoma virus’s ability for infection, replication and killing different types of human cancer cells,” Masmudur said. “We are doing it by identifying and targeting the cellular proteins that restrict myxoma virus replication in human cancer cells.”

Masmudur is a researcher with the Biodesign Center for Immunotherapy, Vaccines and Virotherapy at ASU. The new study was spearheaded by co-corresponding author Grant McFadden, who directs the center and is a leading authority on the myxoma virus and its oncolytic potential.

The new research appears in the Journal of Virology, which has highlighted the new study in its Spotlight section, reserved for especially meritorious articles.

Antiviral granules (seen in red) sprayed into the cytoplasm by the protein DHX9. These granules act to inhibit the virus-fighting capacity of the myxoma virus, which is being explored as a therapy to treat cancer.

Scientists are hoping to design a range of new cancer therapies, based on oncolytic viruses such as myxoma. One challenge in advancing such research is the fact that certain cancers, known for their many-faceted efforts to resist effective therapy, can outwit myxoma virus by using an anti-viral cellular component called RNA helicase A/DHX9.

RNA helicases are members of a large family of proteins considered crucial for RNA metabolism and gene expression. RNA helicase A/DHX9 has been shown to reduce the effectiveness of myxoma virus against cancer cells. It does this by forming anti-viral granules in the cancer cell’s cytoplasm, inhibiting the myxoma virus’s ability to replicate.

The new research identifies the RNA helicase A/DHX9 protein as a potential target for new therapies that could neutralize its antiviral properties, thus improving the cancer-fighting potential of myxoma and other oncolytic viruses.

Richard Harth

Science writer, Biodesign Institute at ASU