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INTERCOAST

Project hindcast and forecast - A report by Anja Singer IC 6

Predictive modelling of macrofauna species in the Jade Bay (North Sea, Germany) and Tauranga Harbour (Bay of Plenty, New Zealand)

End of January 2015 my 5 months research stay at the University of Waikato (Centre of Biodiversity and Ecology Research, CBER) began, supervised by Prof. Dr. Conrad Pilditch and Prof. Dr. Chris Battershill. The main target of my research stay in New Zealand is to apply my Species Distribution Model (SDM), which I developed during the last two years for my primary study area (Jade Bay, North Sea, Germany), on a comparable data set for Tauranga Harbour (Bay of Plenty, New Zealand).

SDMs are useful tools to predict potential suitable species habitats, built on statistical relations between species presences (here: characteristic macrofauna species) and environmental variables (here: high-resolution grids). Since the last decades, characteristic macrofauna species of both tidal flat ecosystems are facing strong climatic- and environmental changes, such as sea-level rise, temperature increase or harbour constructions (http://www.boprc.govt.nz, Schückel & Kröncke, 2013). The key question for this comparative study is, if characteristic species of both study areas show similar range shifts under future climatic- and environmental conditions?

Figure I: Map of Tauranga Harbour showing the 75 sampling sites (macrofauna data and environmental data for heavy metals, sediment grain size, chlorophyll-a and nutrients) (Ellis et al., 2013)

Figure 2: Northern Tauranga Harbour showing the presence of seagrass (Zostera ssp.) in 1959 (red) and 1996 (blue) (Park, 1999).

During my first month abroad I collected species- and environmental data for Tauranga Harbour (e.g. for sediment grain size, heavy metals, chlorophyll-a, nutrients or seagrass beds - figure 1), at the Coastal Marine Field Station and the Bay Of Plenty Regional Council in Tauranga. I will process the data during the next months and run my SDM on them. In addition, I continued writing my results for the Jade Bay about hindcasting species distribution and evaluating model predictions with historical macrofauna data from the 1970s and 1930s. This work will result in a scientific publication that will be published later on this year. Furthermore, I

took the opportunity to talk with experts in my field, e.g. at NIWA (National Institute of Water and Atmospheric Research) or the Faculty of Science in Hamilton.

Besides the work on my own PhD project, I gained additional field work experience. Together with my (guest) working group from the University of Waikato I set up crab experiments on sandflats in order to investigate organic decomposition as a result of different treatments (Tairua, Coromandel Peninsula). Furthermore, I assisted IC5 PhD student Manuela Biondo with her survey at Tauranga Harbour, where we took grab sediment samples and recorded transects along different bio substrates with a drop camera.

Joint working group activity (University of Waikato): Setting up crab experiments in Tairua for the PhD work of Rebecca Gladstone-Gallagher; photo: Rebecca Gladstone-Gallagher.

Joint INTERCOAST activity: Sediment grab sampling and drop camera transects in Tauranga Harbour, as part of the IC5 project of Manuela Biondo (from left to right: Florian Boxberg-IC3, Anja Singer-IC6, Manuela Biondo-IC5, Tobias Kulgemeyer-IC8); photo: Anja Singer.

Additional research that I will carry out after my research stay at the University of Waikato will be to 1) forecast suitable species habitats for characteristic macrofauna species for the Jade Bay using an “ensemble” approach (‘biomod2’ R package), which compares multiple modelling algorithms and 2) to compare the model results of the Jade Bay with those of Tauranga Harbour.

References:

Schückel, U.; Kröncke, I. (2013): Temporal changes in intertidal macrofauna communities over eight decades: A result of eutrophication and climate change. Estuarine, Coastal and Shelf Science, 117, 210-218.

Ellis, J.; Clark, D.; Hewitt, J.; Taiapa, C; Sinner, J.; Patterson M.; Hardy D.; Parks, S., Gardners, B.; Morrison, A.; Culliford, D.; Battershill, C.; Hancock, N.; Hale, L.; Asher, R.; Gower, F.; Brown, E.; McCallion, A.; (2013): Ecological Survey of Tauranga Harbour, MTM report No. 13.

Park S.G. (1999): Changes in Abundance of Seagrass (Zostera ssp.) in Tauranga Harbour from 1959-96; Environment BOP, Environmental Report 99/30, Nov. 1999.

Bay of Plenty Regional Council: http://www.boprc.govt.nz/sustainable-communities/climate-change/ (12.03.15).