Using UAS to aid in Ecological Restoration

Ecological restoration and land management is an evolving field necessary to combat the effects of global climate change, human impact, and sea level rise. Natural systems have shown that they serve as a buffer to rising temperatures, sea level rise, and storm impacts. However, over the course of human history, these systems have become degraded or lost entirely. Restorations occur over a wide variety of environmental habitats ranging from urban/nature interface to extremely remote tundra wetlands.
Scientific monitoring is a crucial step in adapting restoration design and efforts to changes in the system.
Traditional monitoring techniques, such as boots on the ground vegetation surveys, are often difficult to complete, time consuming, and expensive to fund. UAS can provide cost efficient and easily repeatable environmental monitoring surveys. These, either stand alone or combined with other survey techniques, can improve our ability to capture data in real time and make meaningful changes to our restoration programs.
Ecological restoration has become widespread over the past twenty years. In the San Francisco Bay, salt marsh restorations continue to undo years of human influence dating back to the gold rush.
Prior to modern expansion into California, the San Francisco bay front consisted of a mosaic of natural transitional ecosystems lining the shoreline. Much of this historic wetland buffer has been lost, becoming more susceptible to the effects of sea level rise.
The implementation of targeted tidal wetland restoration aims to reverse these losses. (Murphy et al., 2018). Scientific monitoring allows us to evaluate the effectiveness of our restorations and to adapt our management for omnipresent change (Zedler et al., 2012). Traditionally, monitoring is conducted by scientist in person collecting data about the local physical condition (Campbell et al., 2017).
Remote sensing is the distanced practice of gathering and analyzing aerial data to inform on characteristics present on the planet's surface. Remote sensing practices can produce cost­ effective monitoring data over large spatial extents. (Yeo et al., 2020, Chapple & Dronova, 2017). A benefit to remote sensed data collection is that aerial imagery can be taken over restoration sites where physical conditions hinder traditional monitoring techniques. In the case of SF Bay salt marshes, soft substrates make human traverse difficult at best and often impossible.
UAS can provide high spatial resolution while allowing for repeatability and efficiency, relative low cost, and ease of use. Advantages of high-resolution imagery leads UAS to be an advantageous tool for small fine scale salt marsh monitoring. Low cost repeatability allows for repeated monitoring when physical events would otherwise be limited (Hassler & Baysal-Gurel, 2019, Boon et al., 2016). In addition, UAS can generate continuous results across the study area unlike manually collected data which typically use statistical models to infer conditions over the site (DiGiacomo et al., 2020).
UAS technology is advancing quickly and can be implemented effectively in environmental monitoring. Traditional Light Detection and Ranging (LiDAR) surveys can be replaced by advances in photogrammetry, where UAS can extract three-dimensional data (DiGiacomo et al., 2020). Utilizing this technology, digital surface models (DSM) can be developed to aid in the monitoring of landscape level change such as ice cap recession and vegetation cover evolution (Lamsters et al., 2020).

The publication of primary literature studying UAS technology in the environmental field has gained momentum in the past five years. The technology is advancing at such a rate where new studies highlight novel ways to interpret these data. An area of study where UAS technology has not been explored in detail is the implementation of this technology as a practical tool for ecological restoration. Land managers and restoration practitioners can greatly benefit from research that provides basis and justification for the use of UAS technology in the practical realm of restoration ecology.