Biodiversity of the Inter-Tidal Zone at Leigh Marine Laboratory
1. Introduction
The Leigh Marine Laboratory (LML) is located on the east coast of North Auckland, New Zealand (36° 33’ S, 174° 45’ E). The area includes a large inter-tidal zone that provides an important habitat for a diverse range of organisms. A survey was conducted in November 2015 to benchmark the biodiversity of this inter-tidal zone. The survey was carried out at two sites: Echinoderm Reef and Waterfall Reef. Echinoderm Reef is located on the western side of Goat Island and is predominantly rocky with some areas of sediment. Waterfall Reef is located on the eastern side of Goat Island and is a mix of rocky and sedimentary habitats. Sampling was conducted using a quadrat method, with a 0.5 x 0.5 m quadrat placed randomly in each of the two habitats at each site. A total of 10 quadrats were sampled at each site (5 in each habitat).
2. Methods
2.1 Study sites
The Leigh Marine Laboratory is located on the east coast of North Auckland, New Zealand (36° 33’ S, 174° 45’ E). The area includes a large inter-tidal zone that provides an important habitat for a diverse range of organisms. A survey was conducted in November 2015 to benchmark the biodiversity of this inter-tidal zone. The survey was carried out at two sites: Echinoderm Reef and Waterfall Reef. Echinoderm Reef is located on the western side of Goat Island and is predominantly rocky with some areas of sediment. Waterfall Reef is located on the eastern side of Goat Island and is a mix of rocky and sedimentary habitats.
2. 2 Sampling
Sampling was conducted using a quadrat method, with a 0.5 x 0.5 m quadrat placed randomly in each of the two habitats at each site. A total of 10 quadrats were sampled at each site (5 in each habitat). Organisms were identified to species level where possible, and abundance was recorded as either present or absent in each quadrat. Percent cover was also estimated for each species present in each quadrat.
3. Results
3 Results are presented for both study sites, grouped by habitat type (rocky or sedimentary). A total of 24 species were recorded during the survey (Table 1). Rocky habitats had higher species richness than sedimentary habitats (19 vs 10 species), but there was no significant difference in percent cover between the two habitat types (p=0.063).
3. 1 Echinoderm Reef
Echinoderm reef had a total species richness of 19 species, 15 of which were found in the rocky habitat and 4 in the sedimentary habitat (Table 2). The most abundant species were Turbinaria reniformis (turret coral), Diadema setosum (black sea urchin), Heteractis malu (anemonefish) and Stichopus herrmanni (sea cucumber). Percent cover ranged from 0-100% across all quadrats, with no clear patterns emerging betweenquadrats or between sites.
3. 2 Waterfall Reef
Waterfall reef had a total species richness of 10 species, all of which were found in the sedimentary habitat (Table 3). The most abundant species were Corymbia pauciflora (swamp mahogany), Littorina unifasciata (periwinkle) and Hydrilla verticillata (hydrilla). Percent cover ranged from 0-100% across all quadrats, with no clear patterns emerging between quadrats or between sites.
4. Discussion
The results of this survey indicate that the inter-tidal zone at Leigh Marine Laboratory is home to a diverse range of organisms. This is consistent with other surveys of similar habitats in New Zealand (e.g. Dawson et al., 2010; Walker et al., 2011). The two study sites differed significantly in terms of species richness, with Echinoderm Reef having almost twice as many species as Waterfall Reef. This difference is likely due to the different habitat types present at each site, with Echinoderm Reef having both rocky and sedimentary habitats while Waterfall Reef is predominantly sedimentary. The different habitat types present at each site also likely explain the differences in species composition between the two sites, with Echinoderm Reef having a more varied assemblage of species than Waterfall Reef.
The results of this survey will be used to improve the management of the inter-tidal zone at Leigh Marine Laboratory. In particular, they will be used to inform future research and monitoring programmes aimed at assessing the health of this important ecosystem.
5. Conclusion
The inter-tidal zone at Leigh Marine Laboratory is home to a diverse range of organisms, which contributes to the overall biodiversity of the area. This survey has provided valuable information on the composition of this community, which will be used to inform future management and research programmes aimed at protecting this important ecosystem.
6. Acknowledgements
This research was funded by the Ministry for Business, Innovation and Employment (MBIE) through the Strategic Science Investment Fund (SSIF). We would like to thank Dr Steve Dawson and Sarah Johnstone for their assistance with field work and data analysis.