Using broad scale eDNA sampling to identify correlates of platypus occupancy across south eastern Australia

Emily McColl-Gausden¹, Josh Griffiths², Dr Andrew Weeks^1,2, Dr Reid Tingley³

¹The University Of Melbourne, Parkville, Australia, ²EnviroDNA Pty Ltd, Brunswick, Australia, ³Monash University, Clayton, Australia

Abstract:

Species presence-absence data collected over large spatial extents can be time consuming and logistically difficult to obtain. Yet these data are important for ensuring changes in species distributions are accurately monitored and are vital to our understanding of how species respond to global change. Here we demonstrate the use of environmental DNA (eDNA) sampling for collecting species occupancy data across vast spatial scales. We used a systematic environmental DNA sampling regime to survey platypuses at 504 sites across 584,292 km2 of south-eastern Australia. Site occupancy detection models were used to analyse how landscape- and site-level factors affect platypus occupancy, enabling us to incorporate uncertainty at the different levels inherent in eDNA sampling (site, water sample replicate, and qPCR replicate).  Platypuses were more likely to occupy sites in catchments with increased runoff, less zero-flow days, and access to banks suitable for burrowing and were less likely to occupy sites in catchments with a higher proportion of shrubs and grasslands. This study represents the largest spatially scaled eDNA sampling program undertaken to date using a systematic study design. We demonstrate that eDNA sampling can be conducted efficiently over large spatial scales and that this data can be used to understand how landscape or site characteristics affect platypus species occupancy. These methods can be applied to aquatic and semi-aquatic species monitoring globally, providing unprecedented opportunities to understand biodiversity change.

Biography:

I am a PhD student in the Quantitative and Applied Ecology group at The University of Melbourne. I am examining how environmental DNA can be used to gather large scale data and am interested in the effectiveness of novel technologies.