Evaluation of the gap intercept method to provide measurements and indicators of rangeland connectivity

Authors: McCord, Sarah; BREHM, JOSEPH - New Mexico State University; CONDON, LEA - Us Geological Survey; DREESMANN, LEAH - University Of Idaho; ELLSWORTH, LISA - Oregon State University; GERMINO, MATTHEW - Us Geological Survey; Herrick, Jeffrey - Jeff; Howard, Brian; KACHERGIS, EMILY - Bureau Of Land Management; KARL, JASON - University Of Idaho; KNIGHT, ANNA - Us Geological Survey; MEADORS, SAVANNAH - New Mexico State University; NAFUS, ALETA - Bureau Of Land Management; Newingham, Beth; Olsoy, Peter; PIETRASIAK, NICOLE - University Of Nevada; PILLIOD, DAVID - Us Geological Survey; SCHAEFER, ANTHONY - New Mexico State University; Webb, Nicholas - Nick; WHEELER, BRANDI - New Mexico State University; Williams, Christopher - Jason; Young, Kristina

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Rangeland researchers and managers have used the gap intercept method as a standardized method to understand rangeland connectivity for over twenty years. Gap data provide critical information about vegetation structure that can be used to understand ecosystem structure and function including soil erosion by wind and water, biocrust community shifts, changes in plant community dynamics, nutrient availability, fire risk due to fuel connectivity, and wildlife habitat. Understanding these ecosystem functions and threats can be used to guide future management decisions and to understand the success of management actions, including restoration treatments. While a substantive body of research has demonstrated the utility of the gap intercept method for characterizing rangeland connectivity, there are many opportunities to address how gap distributions, shifts in gap distributions, and novel gap-based indicators represent rangeland connectivity and respond to land management. There are opportunities to explore the utility of the gap intercept method to understand other ecosystem processes and services, such as carbon dynamics, and microclimate effects. We encourage the community to continue to collect standardized gap data, having highlighted the value of gap metrics here as well as new opportunities for understanding ecosystems through a lens of connectivity by applying gap indicators to other ecosystem processes and by developing new indicators of connectivity leveraging gap data. 

Technical Abstract: Characterizing the connectivity of materials, organisms, and energy on rangelands is critical to understanding and managing for ecosystem response to disturbances. For over twenty years, scientists and rangeland managers have used the gap intercept method to monitor connectivity. However, using gap intercept measurements to infer ecosystem processes or inform management actions and conservation practices on rangelands has been limited because there are few tools and syntheses to help managers pragmatically interpret gap measurements. In this synthesis, we review the different ways the gap intercept method is conducted and highlight considerations when collecting and using gap intercept data. We discuss what is known about how gap intercept data can be used to assess wind and water erosion, biocrust abundance and composition, soil fertility, plant community dynamics, wildlife habitat provisioning, and fuel connectivity and fire behavior. Finally, we identify emerging opportunities regarding the collection and use of gap intercept data to assess rangeland connectivity and ecosystem health. Through this synthesis we demonstrate the value of the gap intercept method, particularly all-plant canopy gap, in supporting assessment of rangeland condition and vulnerability, and in planning future management actions.