Using terrestrial laser scanning to support ecological research in the rocky intertidal zone

Scale-appropriate, foundational datasets are necessary for ecological analyses of the rocky intertidal ecosystem. We used terrestrial laser scanning (TLS) to characterize and quantify the rocky intertidal zone topography at a western U.S. coastal site (Rabbit Rock, Oregon) to support ecological research relating to potential climate-induced changes in distribution and abundance of intertidal invertebrates and a large-bodied shorebird, the Black Oystercatcher (Haematopus bachmani). Alternate available data (e.g., aerial photography, airborne LIDAR) proved inadequate or infeasible for development of a topographic surface model inclusive of intertidal area from Mean Lower Low Water to Mean Higher High Water tidal elevation. Our TLS-derived topographic surface model competently supported development of an invertebrate distribution model relative to tidal elevation and topography. Using the developed model, we estimated current and future aerial extent of the intertidal zone and potential foraging habitat for Black Oystercatcher in our study area. Intertidal zone area decreased from 7,194 m2 to 6,409 m2 and 3,070 m2 with 1 and 2 m sea-level rise, respectively. Surprisingly, due to the configuration of site substrate, potential foraging habitat for Black Oystercatcher increased from 5,658 to 5,903 m2 with 1 m sea-level rise, but declined to 3,068 m2 with 2 m sea-level rise. Our results demonstrate the utility of TLS for ecological research in the rocky intertidal zone. They further illustrate that climate change effects on ecological conditions may vary considerably depending on local configurations.