Using photogrammetry to create virtual permanent plots in rare and threatened plant communities

Area of Science:

• Ecology
• Environmental Monitoring
• Geospatial Analysis

Background:

• Plant communities face threats from climate change and human activity, necessitating effective monitoring.
• Traditional permanent vegetative plots are not always feasible for tracking community-level changes.
• Developing alternative, non-invasive monitoring techniques is crucial for long-term ecological studies.

Purpose of the Study:

• To evaluate photogrammetry, specifically structure-from-motion (SfM) derived digital surface models (DSMs), as a method for establishing virtual permanent plots.
• To compare plant species presence and percent coverage estimates derived from DSMs with traditional field estimates.
• To assess the feasibility of using photogrammetry for long-term monitoring of plant communities where physical plots are impractical.

Main Methods:

• Utilized iPhone photography to capture 1-m² plots in northeastern United States alpine communities in 2021 and 2022.
• Generated digital surface models (DSMs) from photographs using structure-from-motion (SfM) software.
• Compared field-based estimations of species percent coverage with those derived from the DSMs.

Main Results:

• Digital surface models (DSMs) provide effective, minimally invasive, and permanent records of plant species presence.
• Percent coverage estimations from DSMs showed no significant difference compared to field estimates for most species and substrates.
• Virtual plots established via photogrammetry allow for precise virtual marking of survey locations for future monitoring.

Conclusions:

• Photogrammetry and SfM offer a low-cost, accurate method for surveying and recording sensitive plant communities over time.
• This approach is particularly valuable in areas where traditional permanent plot establishment is not feasible.
• Virtual permanent plots using DSMs enable continuous and accurate ecological surveying efforts.