Visualizing Intertidal Monitoring Using Photo Transects and Discrete Ecological Data 

Siomara Zendejas and Dr. Geoffrey Dilly


Photo transects are information-rich swath surveys used to document inventory of flora and fauna at research sites. They can be used for longitudinal comparisons of shifts in species richness and abundance over time. Technological advances have made it possible for photo transects to be readily employed at all scales and in habitats ranging from coral reefs to boreal forests. In intertidal research, photo transects are mostly based off of aerial drones, permanent point-intercept photo plots, and fixed camera rigs; these are used to monitor both long-term species composition and experimental manipulations. Due to the importance of the intertidal community to overall ocean health, it is imperative to find new ways to utilize photo transects in long term monitoring efforts to better quantify and visualize changes in intertidal communities. Here we match photo transect imagery with discrete transect line biological data as well as co-located temperature loggers to visualize long term species composition changes caused by temperature fluctuations in the rocky intertidal.
Data was collected in the rocky intertidal zone of Santa Rosa Island, California, at two sites: Skunk Point and Bechers Bay. A total of eleven line transect lines were laid out along a 30 m base line 3 m apart and 25 m long. Sessile species within 1 cm² were identified and recorded every 0.25 m. Photo transects were performed on these same lines using a 1 m² photo rig. Photos were taken every 0.65m and assembled using Microsoft Image Composite Editor to build a single swath-survey of the transect line. Temperature data was collected using 20 iButtons permanently deployed at each site. The photos were stitched up and different cover types were estimated as percentages using pixel measurements. Temperature data was averaged out across each zone (splash, high, mid, low) and was then analyzed along with the line transect data using JMP to explore the relationship between cover type and temperature.


Session 2 – 3:00p.m. – 4:15p.m.

Room B – Sierra 1422 

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