DOI: 10.5061/dryad.bcc2fqzck
title: Beagle kelp maps from: One of the least disturbed marine coastal ecosystems on Earth: Spatial and temporal persistence of Darwin’s sub-Antarctic giant kelp forests

description: Aim: Marine habitats and their dynamics are difficult to systematically
 monitor, particularly those in remote locations. This is the case with the
 sub-Antarctic ecosystem of the giant kelp Macrocystis pyrifera,
 which was already noted by Charles Darwin in his accounts on
 the Voyage of the Beagle and recorded on the nautical
 charts made during that expedition. We combined these and other nautical
 charts from the 19th and early 20th centuries with surveys conducted in
 the 1970s and 1980s and satellite detection algorithms from 1984 to 2019,
 to analyse kelp distribution through time and the factors that correlate
 with it. Location: Marine ecoregions of Channels and Fjords of Southern
 Chile, Falkland Islands (Malvinas), and the island of South Georgia.
 Taxon: Macrocystis pyrifera. Methods: We characterised
 309 giant kelp forests by their coastal geospatial attributes.
 Statistically significant variables were included in a conditional
 inference tree to predict kelp forest size. Sea surface temperature (SST)
 records were analysed to confirm temperature ranges over the last four
 decades. Nautical charts, historical surveys, aerial photogrammetry,
 unmanned aerial vehicle (UAV) surveys and satellite imagery were overlaid
 to assess spatial distribution of kelp forest canopies, spanning the
 period 1829–2020. Results: Considering the extensive natural and human
 caused changes over the last two centuries, this diverse kelp ecosystem is
 remarkably persistent. We found that the ocean currents and wave exposure,
 combined with the geomorphological settings of the coastline are the most
 critical factors predicting the extent of the kelp forests. Main
 conclusions: We have described the long-term ecological persistence of the
 kelp forests in this vastly under-studied region that offers a conceptual
 biogeographical model supporting the global importance proposed by Charles
 Darwin 200 years ago (Darwin, 1845). In the current context of
 global change, the need for conservation of this persistent and
 well-preserved marine ecosystem has never been more important.
description: <strong>Beagle Kelp project</strong>
 BeagleKelpMaps and supplementary information
 This is the repository of the original code https://biogeoscienceslaboxford.users.earthengine.app/view/beaglekelpcharts You can explore and download the layers of this map here: https://code.earthengine.google.com/6d7a632defb18891908d337fea47746d Kelp polygons (shapefiles) are in the file Beaglekelppolys.rar* Multiyear maps: Agua Fresca: https://code.earthengine.google.com/f22e097ee30487d882469307e31a78da Goree Roads: https://code.earthengine.google.com/ebca06f9e3327d8c9e937a9e211aee54 Laredo: https://code.earthengine.google.com/3b2132982d155e5afc2df4ebae1251a6 Mitre: https://code.earthengine.google.com/7c2f3dc5f6af8658f6a933ca0938cbb2 Packsaddle Bay: https://code.earthengine.google.com/25302ce879990f84a4fd955dfe45f821 Wollaston: https://code.earthengine.google.com/95714101bc740acbb3df117652ea5e37 South Georgia: https://code.earthengine.google.com/b3dcd842b23666132b395f763a0110f4 Falkland Is. https://code.earthengine.google.com/b427f63c568243fbdfbcdb752fbfdf8f Deseado: https://code.earthengine.google.com/adce87e83f2ed4e055da40eadafe57d1   *Beagle Kelp Polygons (shapefile) Shapefile polygons covering the kelp forests drawn on UKHO nautical charts.  Beagle_Key nomenclature:<br> 1) The satellite-detected kelp areas covered the charted kelp in similar form and extent.<br> 2) The satellite-detected kelp areas had spare pixels over the target kelp canopy: this may mean that the forest is small or with sparse fronds, largely undetected by the satellite sensor.<br> 3) The satellite-detected kelp areas showed patterns not associated with kelp forests.<br> 4) No satellite-detected kelp pixels over the targeted kelp.