## Breadcrumb

-  Publications 
-  Articles 

#           Quantifying plant-soil-nutrient dynamics in rangelands: Fusion of UAV hyperspectral-LiDAR, UAV multispectral-photogrammetry, and ground-based LiDAR-digital photography in a shrub-encroached desert grassland      

      December 8, 2020    

Rangelands cover 70% of the world's land surface, and provide critical ecosystem services of primary production, soil carbon storage, and nutrient cycling. These ecosystem services are governed by very fine-scale spatial patterning of soil carbon, nutrients, and plant species at the centimeter-to-meter scales, a phenomenon known as “islands of fertility”. Such fine-scale dynamics are challenging to detect with most satellite and manned airborne platforms. Remote sensing from unmanned aerial vehicles (UAVs) provides an alternative option for detecting fine-scale soil nutrient and plant species changes in rangelands tn0020 smaller extents. We demonstrate that a model incorporating the fusion of UAV multispectral and structure-from-motion photogrammetry classifies plant functional types and bare soil cover with an overall accuracy of 95% in rangelands degraded by shrub encroachment and disturbed by fire. We further demonstrate that employing UAV hyperspectral and LiDAR fusion greatly improves upon these results by classifying 9 different plant species and soil fertility microsite types (SFMT) with an overall accuracy of 87%. Among them, creosote bush and black grama, the most important native species in the rangeland, have the highest producer's accuracies at 98% and 94%, respectively. The integration of UAV LiDAR-derived plant height differences was critical in these improvements. Finally, we use synthesis of the UAV datasets with ground-based LiDAR surveys and lab characterization of soils to estimate that the burned rangeland potentially lost 1474 kg/ha of C and 113 kg/ha of N owing to soil erosion processes during the first year after a prescribed fire. However, during the second-year post-fire, grass and plant-interspace SFMT functioned as net sinks for sediment and nutrients and gained approximately 175 kg/ha C and 14 kg/ha N, combined. These results provide important site-specific insight that is relevant to the 423 Mha of grasslands and shrublands that are burned globally each year. While fire, and specifically post-fire erosion, can degrade some rangelands, post-fire plant-soil-nutrient dynamics might provide a competitive advantage to grasses in rangelands degraded by shrub encroachment. These novel UAV and ground-based LiDAR remote sensing approaches thus provide important details towards more accurate accounting of the carbon and nutrients in the soil surface of rangelands.

## Citation Information

## Related Content

                  -              Connect           

#### Joel B Sankey, Ph.D.

##### Research Geologist

Southwest Biological Science Center

jsankey@usgs.gov

928-556-7289

#### Joshua Caster

##### Geographer

Southwest Biological Science Center

jcaster@usgs.gov

(928) 556-7129

####             Alan Kasprak (Former Employee)          

##### Research Geologist - Mendenhall Post-Doc

Southwest Biological Science Center

## Related Content

#### Joel B Sankey, Ph.D.

##### Research Geologist

Southwest Biological Science Center

jsankey@usgs.gov

928-556-7289

#### Joshua Caster

##### Geographer

Southwest Biological Science Center

jcaster@usgs.gov

(928) 556-7129

####             Alan Kasprak (Former Employee)          

##### Research Geologist - Mendenhall Post-Doc

Southwest Biological Science Center

### Study Area

### Contact

####               Southwest Biological Science Center - Flagstaff, AZ, Headquarters          

2255 N. Gemini DriveFlagstaff, AZ86001United States

928-556-7094

928-556-7092

### Explore Search

                  - Biology
                  - Ecosystems
                  - United States
                  - Sevilleta National Wildlife Refuge
                  - new mexico

View All **