Coastal Restoration Trust of New Zealand

Coastal Dune Ecosystem Reference Database

Missing the forest and the trees: utility, limits and caveats for drone imaging of coastal marine ecosystems Technical Report

Author
Tait, L.W.; Orchard, S.; Schiel, D.R.
Year
2021
Journal / Source
Remote Sensing
Volume
13
Number
3136
Pages
15
Keywords
intertidal, seaweed, biodiversity, drone, imaging, monitoring, survey
Summary
Abstract: Coastal marine ecosystems are under stress, yet actionable information about the cumula- tive effects of human impacts has eluded ecologists. Habitat-forming seaweeds in temperate regions provide myriad irreplaceable ecosystem services, but they are increasingly at risk of local and regional extinction from extreme climatic events and the cumulative impacts of land-use change and extractive activities. Informing appropriate management strategies to reduce the impacts of stressors requires comprehensive knowledge of species diversity, abundance and distributions. Remote sensing un- doubtedly provides answers, but collecting imagery at appropriate resolution and spatial extent, and then accurately and precisely validating these datasets is not straightforward. Comprehensive and long-running monitoring of rocky reefs exist globally but are often limited to a small subset of reef platforms readily accessible to in-situ studies. Key vulnerable habitat-forming seaweeds are often not well-assessed by traditional in-situ methods, nor are they well-captured by passive remote sensing by satellites. Here we describe the utility of drone-based methods for monitoring and detecting key rocky intertidal habitat types, the limitations and caveats of these methods, and suggest a standardised workflow for achieving consistent results that will fulfil the needs of managers for conservation efforts.