Dr Konstanze Steiner1, Dr Georgia Thomson-Laing1, Mr Jacob Thomson-Laing1, Dr Marcus Vandergoes2, Dr Tom Drinan3, Dr Anastasija Zaiko4, Dr Susie Wood5,1
1Cawthron Institute, Nelson, New Zealand, 2GNS, Wellington, New Zealand, 3Waters of LIFE, Croom, Ireland, 4Sequench, Nelson, New Zealand, 5Waterways Centre, Lincoln University, Lincoln, New Zealand
Biography:
Konstanze Steiner is a molecular scientist, who has been working at the Cawthron Institute in Nelson for 6 years. She has a background in environmental toxicology, looking at the updated mechanisms of toxins in aquatic animals. Her focus has now shifted to using eDNA methods in aquatic environments. She is involved in research programs, such as the biodiversity critical step of the MBIE program "Our lakes, our future", as well as in the commercial development of targeted eDNA assays at Cawthron, such as kākahi, kōura or Asian Clam.
Abstract:
Knowledge on the current and historical distribution of taonga species such as kākahi (freshwater mussel; Echyridella) and kōura (crayfish; Paranephrops) is crucial as they are of high cultural significance, and they play important roles in freshwater ecosystems. Traditional monitoring is often time-consuming and costly, which limits the number of sites where surveys can be undertaken. We recently developed a droplet digital PCR assay to detect and distinguish the three species kākahi present in Aotearoa. We then applied this to (1) water samples from Ō Tū Wharekai (Ashburton Lakes) to compare the occurrence and concentration of eDNA with density data obtained from diver surveys and to use a statistical approach to determine the optimal number of samples required when establishing a monitoring programme, and (2) nine lake sediment cores to investigate the historical presence of kākahi. In the water samples eDNA was detected at most sites where kākahi was present and eDNA occupancy was 79%. Modelling suggested that 4 sampling sites are necessary for a detection probability of 99%. Kākahi eDNA was detected from sediment layers in seven of the nine sediment cores, however, it was only consistently identified in three lakes and only in sediment less than about 500 years old. We were unable to elucidate the reason for these non- or poor detections but speculate it may be due to proximity to source populations, the ability of the sediment to absorb and facilitate preservation of DNA or abiotic and biotic factors.