File Geodatabase Feature Class
Tags
The Nature Conservancy, University of California, Los Angeles, Hakai Institute, Northern California, Kelp, Classification, Remote Sensing, Unoccupied Aerial Vehicles, UAV, Mendocino County
This dataset was processed by The University of California, Los Angeles (UCLA) and The Nature Conservancy, California (TNC) and is used to assess emergent kelp canopy area at priority sites, established by the Sonoma-Mendocino Bull Kelp Recovery Plan (1), along the North Coast of California. Imagery was collected by unoccupied aerial vehicle (UAV) pilots from TNC, UCLA, and the Hakai Institute. This is a simplified and lower resolution version of the data for quicker visualization and should not be used for analysis. The higher resolution data will be downloaded in tandem with this version in BIOS.
This dataset derived from mosaicked RGB imagery, targeting only exposed kelp in priority sites along the California coastline in Mendocino County. The imagery was acquired using DJI Phantom series UAVs with the standard RGB sensor; sensor resolution ranged from 12.4 - 20.8 megapixels. The ground sampling distance ranged from 2.5-3.8 cm. Pilots aimed for 75-80% front/side overlap at 400ft (120m) altitude. Flights were coordinated to coincide with annual, peak biomass of Nereocystis luetkeana and the lowest tide of the month as tidal height and surface currents have been shown to impact the amount of kelp canopy exposed on the water surface (2), and these impacts can vary regionally (3). Imagery was mosaicked using a standard mapping software (i.e. DroneDeploy, Pix4D, and Agisoft Metashape).
Emergent kelp pixels were identified in each UAV image using a deep learning algorithm (KelpOMatic v2) (4). This method does not require any additional masking and provides an efficient and accurate method for extracting kelp extent form UAV imagery which can take into account radiometric and spectral variability present in the imagery. The output from the KelpOMatic is a raster of pixels classified as emergent kelp; pixel classification of emergent kelp is not species-specific. This raster is converted to a vector shapefile, features less than 0.2 m2 are removed, and the rest of the scene is manually edited by expert analysts to increase accuracy.
The imagery for these sites was collected between September 14 - September 15, 2022. The date of imagery collection, UAV launch, and UAV land times for each site are included below:
|
Site |
Date |
LaunchTime |
LandTime |
|
Mendocino Noyo Bay (MNB) |
20220914 |
7:46 AM |
8:21 AM |
|
Mendocino Caspar Cove (MCC) |
20220914 |
8:21 AM |
8:50 AM |
|
Mendocino Frolic Cove (MFC) |
20220914 |
9:36 AM |
9:51 AM |
|
Mendocino Big River (MBR) - south |
20220915 |
8:12 AM |
8:47 AM |
|
Mendocino Big River (MBR) - center |
20220915 |
9:09 AM |
9:36 AM |
|
Mendocino Albion Cove (MALC) |
20220914 |
7:50 AM |
8:21 AM |
|
Mendocino Greenwood Creek (MGC) |
20220915 |
8:53 AM |
10:10 AM |
|
Mendocino Dark Gulch (MDG) |
20220915 |
7:34 AM |
7:44 AM |
|
Mendocino Van Damme (MVD) |
20220915 |
8:32AM |
10:13 AM |
|
Mendocino Saunders Reef (MSR) |
20220915 |
8:31 AM |
9:28 AM |
Attributes:
SurveyID: priority site surveyed by UAV. Sites were established by the Sonoma-Mendocino Bull Kelp Recovery Plan (1) .
Type: denotes whether a pixel was classified as kelp or no data, as well as the extent of the UAV survey (i.e. Survey Extent). Pixels within the survey extent classified as No Data were visually obstruc ted (e.g. by sun glint) and were unable to be classified. Pixels within the survey extent not classified as Kelp nor No Data are by default not kelp pixels (e.g. open water, coastal rocks, etc.)
TNC, UCLA, and GFA must be credited with the distribution of these data. Suggested citation: The Nature Conservancy, University of California, Los Angeles, and Greater Farallones Association. (2022). Emergent kelp canopy pixel classifications of North Coast priority kelp forest sites. https://apps.wildlife.ca.gov/bios6/ Contacts: University of California, Los Angeles: Dr. Kyle Cavanaugh, kcavanaugh@geog.ucla.edu The Nature Conservancy, California: Vienna Saccomanno, v.r.saccomanno@tnc.org (1) Hohman, R., Hutto, S., Catton, C. and F. Koe. 2019. Sonoma-Mendocino Bull Kelp Recovery Plan. Plan for the Greater Farallones National Marine Sanctuary and the California Department of Fish and Wildlife. San Francisco, CA. 166 (2) Britton-Simmons, K., Eckman, J. E. and Duggins, D. O. Effect of tidal currents and tidal stage on estimates of bed size in the kelp Nereocystis luetkeana. Marine Ecology Progress Series vol. 355 95-105 (2008) (3) Cavanaugh, K. C., Cavanaugh, K. C., Bell, T. W., and Hockridge, E. G. (2021). An Automated Method for Mapping Giant Kelp Canopy Dynamics from UAV. Front. Environ. Sci, 8, 587354. (4) https://hakai-segmentation.readthedocs.io/en/latest/
This is a simplified and lower resolution version of the data for quicker visualization and should not be used for analysis. The higher resolution data will be downloaded in tandem with this version in BIOS.
DISCLAIMER: (1) Timing of the survey is important, particularly with respect to peak kelp biomass, conditions in the ocean (e.g. tides and currents), and storms. Seasonal variability may account for differences in surveys which may not reflect a change in the kelp bed's extent or productivity. (2) Statistical significance in change of area should be evaluated. (3) Survey sensors across time and space may not be consistent. (4) Because wind and weather conditions varied significantly throughout the data collection process, surveys were not restricted to a specific tidal height or current speed - and data were collected when field conditions allowed for stable UAV launch and landing. While this limitation may introduce bias into area estimates, these data still inform the location of kelp canopy on fine spatial scales.
Extent
| West | -123.834144 | East | -123.650379 |
| North | 39.436966 | South | 38.847453 |
| Maximum (zoomed in) | 1:5,000 |
| Minimum (zoomed out) | 1:150,000,000 |
This is a simplified and lower resolution version of the data for quicker visualization and should not be used for analysis. The higher resolution data will be downloaded in tandem with this version in BIOS.
DISCLAIMER: (1) Timing of the survey is important, particularly with respect to peak kelp biomass, conditions in the ocean (e.g. tides and currents), and storms. Seasonal variability may account for differences in surveys which may not reflect a change in the kelp bed's extent or productivity. (2) Statistical significance in change of area should be evaluated. (3) Survey sensors across time and space may not be consistent. (4) Because wind and weather conditions varied significantly throughout the data collection process, surveys were not restricted to a specific tidal height or current speed - and data were collected when field conditions allowed for stable UAV launch and landing. While this limitation may introduce bias into area estimates, these data still inform the location of kelp canopy on fine spatial scales.