Marine Biodiversity - Alison MacDiarmid - Marine Biodiversity of Aotearoa New ZealandPresentation Transcript
Marine Biodiversity of Aotearoa New Zealand Alison MacDiarmid NIWA [email_address] DD 04 386 0370 Mobile: 027 552 7780 Image courtesy of GeoEye/NASA
Number of marine species in NZ
NZ has a particularly rich marine flora and fauna
There are 17,135 known living species in the EEZ
This diversity includes 4,315 known undescribed species in collections
Unknown undescribed species are probably in excess of about 17,000 species
Most diverse groups
Molluscs (bivalves, snails etc) 3,593 species
Arthropods (crabs, lobsters barnacles etc) 2,711 species
Chordates (fish, sharks, mammals, birds) 1,565 species
Sponges 1,435 species
Cnidarians (corals, gorgonians, medusae & hydroids) 1,116 species
Levels of Endemism
Almost half of NZ’s known species are endemic (species not occurring elsewhere)
The level of endemism varies from a high 95% in sponges to low levels among marine mammals
Poorly known groups in New Zealand
Bacteria diversity is poorly known. There are 40 named species of blue-green Cyanobacteria but there have been few studies of marine bacteria in the oceans surrounding New Zealand.
Marine flatworms, nematodes and parasitic protozoan species are particularly poorly known from NZ.
Poorly sampled regions in NZ’s EEZ
Marine shelf habitats along the west coasts of both main islands remain poorly sampled.
So are most deepwater habitats below about 2000m that constitute half NZ’s EEZ.
Reasons for high levels of marine biodiversity and endemism
Isolation in SW Pacific – low gene flow
Particularly rich and varied seascape
Extension over 30 o of latitude
Position on active plate boundaries with consequent folding, faulting and volcanic activity
Position relative to major water masses and current flows
Recent research has identified the top threats across all NZ marine habitats
The top ten are:
Rise in ocean temperatures
Change in current strength
Scallop and oyster dredging
Dumping of dredge spoils
Sea level rise
Note that half of these stem from largely international threats associated with climate change and apart from documenting their impact we are dependent on global initiatives to reverse their effects. The remainder are under NZ’s control.
Implications for management
The large number of species in NZ waters indicates management responsibilities are also great.
The large proportion of still undescribed species underscores the need to fully document NZ’s marine diversity – difficult to achieve this critical diagnostic within current levels of funding and expertise.
The high level of endemism means that NZ cannot rely upon the good stewardship of biodiversity by other countries to maintain our species – we are responsible.
The need for self reliance needs to be translated in policies and actions that maintain the integrity and long-term sustainability of the environments and habitats in which our marine biodiversity occurs.