Laminaria hyperborea records in Ireland
In November 2019, the written records of phycologists and old texts were accessed in the Linnaean Society of London to investigate the study ofL. hyperborea from 1700 to present day. National herbaria were visited to examine kelp voucher specimens from Ireland over the same time period, though we must note that there are, in general, very few records of large brown algae in these herbaria: National University of Ireland Galway (M. Guiry, 1 record, Finavarra County Clare), The National Botanic Gardens of Ireland (2 records, Clifden County Galway), Trinity College (0 records), and Natural History Museum of London (3 records, Clare Island). The lack of voucher specimens is likely due to the difficulty in preserving thick thalli on paper and many specimens were likely jellied rather than pressed for preservation (Tsuda & Abbott, 1985). Precise collection details were not noted on many herbarium sheets making it difficult to ascertain the location of collection, therefore herbarium data were not included when mapping kelp records along the coastline through time. Site records for L. hyperborea were downloaded or donated from the Global Biodiversity Information Facility (January10th, 2020, gbif.org), Ocean Biogeographic Information System (January 10th, 2020, obis.org), National Biodiversity Data Centre (September 19th, 2019, biodiversityireland.ie), and the Environmental Protection Agency (September 17th, 2019). All data were concatenated, and quality filtered for duplicate records (i.e., same coordinates, same date) and correct geographical location (i.e., points on land were removed). Data were then sorted by year of recording and number of years recorded to highlight sites accessed earliest within the country (‘period of first record’; Figure 1) and of great interest (‘number of years recorded’; Figure 2). Overall, recording effort increased as we approach the present day, with a boom in the 1990s, however few sites were recorded multiple times (Table 2).
Records for kelp forests were provided through recreational Comhairle Fo-Thuinn (CFT) dive clubs throughout the country, the BIOMAR data set (Picton & Morrow, 2006), and recent Irish Research Council and Environmental Protection Agency projects (K. Schoenrock, personal communication), and these were analysed separately as the distribution of kelp ecosystems (not just individual kelp sightings or drift algae). Kelp ecosystems (including survey data) have significantly fewer records (Figure 3) in comparison to kelp records (Figure 1), however there is some overlap. We hope that future observations of L. hyperboreawill include more metadata, such as whether the kelp was found in situ, and whether it was in a kelp forest, park, or other habitat, or on a strandline (as beach wrack). The difference between a kelp forest or park is generally described as a reduced density of large kelp individuals, generally adjacent to a kelp forest, although there is no ecological distinction to date (Parr, 2020).