What makes KI reefs unique?
Reef environments around Kangaroo Island are highly diverse due to the island’s unique and varied coastal geomorphology, complex oceanography and central position, where the distribution of many eastern, western and southern Australian marine species overlap. The more sheltered north coast experiences strong tidal currents through the constriction of Backstairs Passage and Investigator Strait, while the southern coastline is exposed to the constant and unimpeded weather systems of the Southern Ocean. As a consequence KI boasts highly varied coastal environments and a rich marine biological diversity.
Biodiversity and condition of subtidal reefs
On healthy temperate reefs, marine algae dominate, providing complex habitats and the foundations to many food webs through primary production. KI’s reefs are known to support in excess of 600 species of marine algae, making the island, for its size, richer in number of species than most other parts of Australia. Relatively low human impacts mean that species such as Western Blue Groper (Achoerodus gouldii), Weedy and Leafy Sea Dragons (Phyllopteryx taeniolatus and Phycodurus eques), Blue Devil (Paraplesiops meleagris) and Harlequin Fish (Othos dentex), whose numbers have declined significantly elsewhere are present in high abundances around the island.
How is reef biodiversity assessed?
KI NRM in partnership with Reef Life Survey (RLS) and community volunteers has surveyed subtidal reef sites around the island. RLS is a program that links volunteer divers, scientists and natural resource managers and uses standardised monitoring techniques to assess subtidal reefs which can better inform marine research and conservation strategies. In 2005 and 2006, baseline biodiversity data was collected from eight representative subtidal reef sites. A total of 41 fish species comprising almost 6,000 individuals was recorded.
In 2013 RLS returned to the island to repeat and expand the monitoring program, surveying 10 additional sites representative of the subtidal reef found on the northern coast of KI. This survey documented 142 species of fish and invertebrates and nearly 14,900 individuals. See report here.
Just like subtidal reefs around the island, KI’s intertidal reefs are highly varied and diverse, supporting complex communities of algae and invertebrates. The condition of intertidal reefs is related to remoteness and a range of direct and indirect pressures. Situated between the high and low water mark, intertidal reefs are easily accessed and for this reason are completely protected from human harvesting in South Australia under the Fisheries Management Act 2007. Despite this protected status, intertidal reefs are still subject to human impacts such as illegal harvesting, trampling by beachcombers, and also the effects of excessive nutrients or sediments entering the marine environment as terrigenous runoff.
To better understand the condition of KI’s intertidal reefs five sites were monitored in 2006 with the aim of benchmarking biodiversity and identifying indicator species for long-term intertidal reef health. A total of 150 species from five major taxa were recorded during the survey. There were distinct differences in biodiversity between monitoring sites. The details of this survey can be found here .
Community partners and participation
Friends of the Sea (FOTS) is the first underwater nature club on KI and has more than 40 members. The group has attracted funds from both federal Caring for Our Country and state NRM Community grants to help conduct RLS and reef monitoring events all around the coast of KI. FOTS volunteer divers and snorkelers were instrumental in collecting data for the 2013-14 Diving Deeper: expanding community stewardship of Kangaroo Island’s rocky reefs project, which aimed to increase our knowledge of KI’s reef biodiversity by engaging community members and fostering public stewardship of KI’s marine environment.
Natural Resources KI also collaborates with South Australian Conservation Research Divers (SACReD). SACReD is a marine citizen science group founded and managed by marine ecologist Janine Baker. SACReD was formed in 2007 to enable divers to participate in grant-assisted, field-based voluntary research on uncommonly recorded, cryptic and endemic marine fishes and invertebrates. You can view SACReD reports on Kangaroo Island marine fishes and invertebrates .
Natural Resources KI can connect you with the FOTS volunteer group, who are always looking for new members to be trained and involved in dive or snorkel fish counts. If you would like to be involved please contact Natural Resources Kangaroo Island on 8553 4444, or email email@example.com