DOI: 10.5061/dryad.8gtht76w3
title: GIS data of urchin barren mapping in Northeastern New Zealand

description: On shallow rocky reefs in northeastern Aotearoa, New Zealand, urchin
 barrens are recognised as indicators of the ecosystem effects of
 overfishing reef predators. Yet, information on their extent and
 variability is lacking. We use aerial imagery to map the urchin barrens
 and kelp forests on reefs (&lt;30 m depth) across seven locations,
 including within two long-established marine reserves and a marine
 protected area that allows recreational fishing. Urchin barrens were
 present in all locations and were restricted to reefs &lt;10-16 m
 deep. This archive contains ArcGIS shapefiles and layer files for all of
 the maps used in this study. The study area extends from Cape Reinga in
 the far north of the North Island to Tawharanui in the Hauraki Gulf near
 Auckland. Regional scale base maps of the prominent marine habitats were
 included along with the seven fine-scale maps where the kelp forests and
 urchin barrens were mapped.
description: The GIS shapefiles produced in this study were hand-drawn over
 layers of low-level aerial photography taken in specific conditions, which
 maximised the visible depth observable to create polygons to depict the
 habitat boundaries of the shallow reef. Of particular interest was the
 mapping of urchin barrens. Ground truthing surveys creating point data and
 underwater imagery were also brought into the GIS project to assist in
 drawing the reef habitat polygons. Arc layer files contain a common
 symbology across the seven study maps to aid the interpretation of the
 mapping. Further information on the methodology used in the mapping can be
 found in two published papers and four technical reports corresponding to
 the maps. The Readme file details where technical reports and published
 reports can be downloaded from the internet.
description: # GIS data of urchin barren mapping in Northeastern New Zealand
 GIS mapping resources
 supporting the research article: Kerr, V.C. Grace R.V. (deceased), and
 Shears N.T., 2004. Estimating the extent of urchin barrens and kelp forest
 loss in northeastern Aotearoa, New Zealand. Kerr and Associates,
 Whangarei, New Zealand. ## Description of the data and file structure Four
 folders in this archive contain ArcGIS shapefiles with the extension
 (.shp). The shapefiles can be uploaded to ArcGIS or any ArcGIS-compatible
 software to view and access the files' spatial data and habitat
 attributes. It is essential to retain the associated files in each folder
 as these are system files required by ArcGIS to open and use the
 shapefiles. Each shapefile has six associated files with extensions: .avi,
 .CPG, .dbf, .prf, .sbn, and .sbx. In this archive are maps based on
 polygons drawn to depict habitat boundaries of biological and physical
 habitats in the shallow coastal areas of Northeastern New Zealand. Seven
 study areas, which feature urchin barrens and kelp forest habitats, are
 mapped at fine scales. Also in the archive are two Regional scale habitat
 maps of the coastal area created at a larger scale, providing full spatial
 coverage of the Northeast Region. The Regional scale maps provide spatial
 area data of shallow rocky reefs and other prominent habitats. Details of
 additional GIS resources to assist the use of the habitat maps are listed
 for each folder below:  1)      Folder: /*7 Habitat maps full data 2023*.
 Includes the seven fine-scale habitat maps drawn at a scale allowing for
 mapping urchin barrens. The locations are Maitai Bay, Doubtless Bay,
 Waewaetoria Island, Maunganui Bay, Mimiwhangata, Leigh Marine Reserve and
 Tawharanui Marine Reserve. Each mapping file has the location name in the
 file name. For each of these map shapefiles, there is a layer file (extn:
 .lyr). The layer file is a GIS format file that should be kept in the same
 folder as the mapping shapefiles. The layer file contains a symbology that
 can be applied to the open map shapefile to display the different habitats
 (polygons) in a colour scheme, which aids the interpretation of the
 habitat mapping data.  2)      *Folder: /Associated Mapping resources* has
 a large-scale GIS shapefile (extn: shp) of the New Zealand coast and a GIS
 shapefile (extn: shp) of the Marine Protection Area boundaries for
 Mimiwhangata Marine Park, Leigh Marine Reserve and Tawharanui Marine
 Reserve. These two files add a useful context to the display and
 interpretation of the mapping files.  3)      *Folder: /Regional scale
 base maps* have the shapefiles (extn: .shp) for the two base maps used in
 the study for the Northland East and North coast and a Northern section of
 the Hauraki Gulf where the Leigh and Tawharanui areas are located. The
 file names include these location names. The base maps entirely cover
 shallow reefs in the Regional study area but were not mapped at a scale
 that allowed for the mapping of urchin barrens. Both of these shapefiles
 for the Regional maps have associated layer files (extn: .lyr), which can
 be used to display a suggested symbology for the habitat polygons, making
 it easier to interpret the maps.  4) *Folder: /Time series analysis* has
 the shape files (extn: .shp) of habitat boundaries (polygons) for two
 locations at Maitai Bay and Mimiwhangata where urchin barrens and kelp
 forest were mapped using aerial phtography for years ranging from 1944 to
 2023 creating an opportunity to analyse loss of kelp forests over time due
 to the expansion of urchin barrens. ## Sharing/Access information The
 collection of GIS files of the mapping studies archived here, except for
 the Tawharanui Marine Reserve and the Regional Base map for Hauraki Gulf,
 have either published articles detailing the methods used or have
 unpublished technical reports with details of the fieldwork supporting the
 mapping process. Researchers are welcome to contact the Author, Vince
 Kerr, at for queries about these
 resources. Access links to these mapping studies are listed below. Kerr,
 V.C., Rutene, W., Bone, O., 2020. Marine habitats of Maitai Bay and the
 exposed coast of the Karikari Peninsula. A report prepared for Te Whānau
 Moana/Te Rorohuri, Maitai Bay, Karikari Peninsula, Northland and the
 Mountains to Sea Conservation Trust. Available online from:
 (Download
 archive) The New Zealand National Library digital library, ISBN
 978-0-473-56131-4, Download link
 Grace, R.V., Kerr, V.C., 2005. Intertidal and subtidal habitats of Doubtless Bay, Northland, N.Z. Contract report for the Department of Conservation, Northland Conservancy, Whangarei. Available online from: (Download archive) The New Zealand National Library digital library, ISBN, 978-0-473-69908-6 Download link Kerr, V.C., Grace, R.V., 2015. Marine habitats of the proposed Waewaetorea Marine Reserve. A report prepared for Fish Forever, Bay of Islands Maritime Park Inc. Available online from: (Download archive) The New Zealand National Library digital library, ISBN 978-0-473-34573- Download link Kerr, V.C., 2016. Marine habitats of the proposed Maunganui Bay Marine Reserve. A report prepared for Fish Forever, Bay of Islands Maritime Park Inc. Available online from: (Download archive) The New Zealand National Library digital library, ISBN 978-0-473-39499-8, Download link Kerr, V.C., Grace, R.V., 2005. Intertidal and subtidal habitats of Mimiwhangata Marine Park and adjacent shelf. Department of Conservation Research and Development Series 201, 55 p. Available online from: (Download archive) Department of Conservation, New Zealand ISSN 1176 8886 ISBN 0478226780 Download link Leleu, K., Remy-Zephir, B., Grace, R., & Costello, M. J. (2012). Mapping habitats in a marine reserve showed how a 30-year trophic cascade altered ecosystem structure. Biological Conservation, 155, 193-201. Regional Base Map Kerr, V.C., 2010. Marine Habitat Map of Northland: Mangawhai to Ahipara Vers. 1. Technical Report, Department of Conservation, Northland Conservancy, Whangarei, New Zealand. Department of Conservation ISBN: 978-0-478-14789-6 (Printed copy) ISBN: 978-0-478-14790-2 (Web PDF)\ ## Code/Software The ArcGIS format shapefiles and layer files in this archive were created in ArcGIS 10.3. These files are compatible with all ArcGIS and ArcPro software and other third-party GIS applications that can use ArcGIS format files.