The surface areas of 12 subtidal seagrass Zostera muelleri beds at the islands and adjacent mainland shores of the eastern Bay of Islands (35° 12′ S, 174° 10′ E), New Zealand were estimated from aerial images. It appears that little subtidal seagrass existed until after the early-1950s, so significant beds here may be a relatively recent biome. Possible explanations for recent emergence of subtidal seagrass include that debilitating periods of turbid water and pulses of sedimentation associated with the land clearances of the late 1800s had worked through the marine ecosystem. An overall peak in seagrass-cover in the 1960s to 1980s was followed by declines in several beds in the 1990s to 2000s, with recovery since. The temporal presence of seagrass was well-correlated among the three mainland beds, and moderately well among the south-facing beds on the islands, consistent with mechanisms driving seagrass establishment and persistence operating at reasonably broad scales.
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How to cite
Researchers should cite this work as follows:
Booth J (2024). Recent (post-1930) changes in the extent of subtidal seagrass (Zostera muelleri) beds of the eastern Bay of Islands, New Zealand. Version 1.4. Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node. Occurrence dataset. https://nzobisipt.niwa.co.nz/resource?r=zostrea_boi_nz&v=1.4
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The publisher and rights holder of this work is Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node. This work is licensed under a Creative Commons Attribution (CC-BY 4.0) License.
This resource has been registered with GBIF, and assigned the following GBIF UUID: a8786b61-49b6-4d45-afc1-4d50bc434e50. Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node publishes this resource, and is itself registered in GBIF as a data publisher endorsed by Ocean Biodiversity Information System.
- Metadata Provider ●
- Originator ●
- Point Of Contact
Bay of Islands, New Zealand
|South West [-35.236, 174.161], North East [-35.212, 174.262]
|Zostrea muelleri (Seagrass)
|Start Date / End Date
|1935-01-01 / 2017-12-31
Interpretation from aerial photography
|Bay of Islands, New Zealand
Method step description:
- Aerial images useful in defining the extent of the main subtidal seagrass beds over time were scanned/downloaded, with particular focus on early (pre-satellite) ones. The aim was to acquire a time-series, with at least one image every decade through to the present, that could be used to identify any large-scale (on the order of ≥20%) changes in the seagrass footprint. High-resolution imagery spanning multiple beds was particularly useful because such depictions typically included well-established beds that provided reference for smaller and less well-known ones. Images taken at intervals shorter than a decade – even those separated by a year – were also useful because they could potentially indicate how much the surface manifestation of the seagrass beds changed over short timeframes. (Although plant-condition is important in the dynamics of seagrass, this is not readily assessed from aerial imagery. As it turned out, almost all images were from spring and summer, when this seagrass is typically most lush.
- Booth, J.D., 2019. Recent (post-1930) changes in the extent of subtidal seagrass (Zostera muelleri) beds of the eastern Bay of Islands, New Zealand. New Zealand Journal of Marine and Freshwater Research, 53(1), pp.113-127. https://doi.org/10.1080/00288330.2018.1513409
marine, harvested by iOBIS