GIS data of urchin barren mapping in Northeastern New Zealand
Data files
Feb 05, 2024 version files 30.06 MB
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Northland_Urchin_Barren_Studies_GIS_Data.zip
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README.md
Abstract
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 (<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 <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.
README: GIS data of urchin barren mapping in Northeastern New Zealand
https://doi.org/10.5061/dryad.8gtht76w3
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 vince@kerrandassociates.co.nz 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:
https://kerrandassociates.co.nz/completed-works.html (Download archive)
The New Zealand National Library digital library, ISBN 978-0-473-56131-4, Download link https://natlib-primo.hosted.exlibrisgroup.com/primo-explore/fulldisplay?docid=NLNZ_ALMA11357892150002836&context=L&vid=NLNZ&search_scope=NLNZ&tab=catalogue&lang=en_US
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:
https://kerrandassociates.co.nz/completed-works.html (Download archive)
The New Zealand National Library digital library, ISBN, 978-0-473-69908-6 Download link https://natlib-primo.hosted.exlibrisgroup.com/permalink/f/1s57t7d/NLNZ_ALMA11403906010002836
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:
https://kerrandassociates.co.nz/completed-works.html (Download archive)
The New Zealand National Library digital library, ISBN 978-0-473-34573- Download link https://natlib-primo.hosted.exlibrisgroup.com/permalink/f/1s57t7d/NLNZ_ALMA11271126390002836
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:
https://kerrandassociates.co.nz/completed-works.html (Download archive)
The New Zealand National Library digital library, ISBN 978-0-473-39499-8, Download link https://natlib-primo.hosted.exlibrisgroup.com/permalink/f/1s57t7d/NLNZ_ALMA11287730400002836
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:
https://kerrandassociates.co.nz/completed-works.html (Download archive)
Department of Conservation, New Zealand ISSN 1176 8886 ISBN 0478226780 Download link https://www.doc.govt.nz/about-us/science-publications/series/doc-research-and-development-series/
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. https://doi.org/10.1016/j.biocon.2012.05.009
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)\
https://www.doc.govt.nz/documents/conservation/marine-and-coastal/northland-marine-habitat-map-report-1.pdf
https://www.doc.govt.nz/about-us/science-publications/conservation-publications/marine-and-coastal/marine-protected-areas/marine-habitat-map-of-northland-mangawhai-to-ahipara/
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.
Methods
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.