An island expedition

two dolphins seen from the deck of the ferry

Santa Cruz Island Reserve, Sept. 25-29, 2018

The CHI team headed to the NRS’s Santa Cruz Island Reserve, located on California’s largest island, for our next site field scouting trip. On the third site visit in our series of 12, we are continuing to try to understand patterns and connections between freshwater availability and the health and distribution of vegetation. Santa Cruz Island is really a special place that we all felt fortunate to explore new research opportunities and collect data.

We spent quite a bit of time with Lynn McLaren-Dewey of the NRS and David Dewey of TNC who shared their years of Island wisdom, stories, insight, and great cooking. One particular observation that we all found interesting was that the Bishop Pine mortality in the last two years on the Island has been absolutely staggering to the point where there is 90% mortality in most areas. At the same time, there seems to have been an observed (by David) increase in the base flow of the creek next to Christy despite the last two years being poor rain years begging the question if large-scale Bishop Pine mortality may have led to more water in downstream channels.

While wind and fog grounded us the first two days, we hiked for several miles to install and survey semi-permanent ground control points (GCPs) to more accurately tie the UAV based imagery to the land and reduce the amount of time spent in the field in the future.

Brief windows of good weather let us capture some data over the following two days. Jim and I used a DJI M100 quadcopter equipped with a Micasense RedEdge multispectral sensor to capture some of the dead standing stands of Bishop Pine to help efforts to map patterns in mortality across the Island. Meanwhile, Kerri and Jacob flew another similarly equipped DJI M100 on a ridgeline in the West End where Kerri has long time series soil moisture data. The hope is to use these field sensors along with our newly captured UAV imagery to understand how patterns in microtopography (derived from the UAV imagery) and fog influence patterns of soil-plant moisture in a generally water-limited environment. Finally, on our way to the boat the last day we flew a 300-acre area near the main ranch that burned in March 2018, since most of the Island has not burned since the 1930s, this became a unique chance to study Island pyrogeography and post-fire vegetation recovery.

All in all we captured about 1,000 acres of data in RGB and multispectral with GCPs and laid out a great permanent plot to revisit seasonally.

I’m really proud that we captured a lot of good data under some tenuous conditions. A huge thank you to Lynn, David, and Lyndall for helping us pull it all off!  Now we have lots of data to process and even more to continue talking about. Attached is a timelapse of one of our drives so those who couldn’t be there can spend ~30 seconds bouncing along the roads with us.


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