Miss Ualani Miller1,2,3, Dr Sally Maxwell1,2, Dr Aleicia Holland1,3, Dr Ewen Silvester1,3, Dr Michael Shackleton1,2,3

1La Trobe University, Albury Wodonga, Australia, 2Centre for Fresh Water Ecosystems – La Trobe University, Albury Wodonga, Australia, 3Research Centre for Applied Alpine Ecology, Australia

Biography:

Ualani Miller is a freshwater ecologist and recent graduate of the La Trobe Bachelor of Science (Honours) program. Her research focuses on the impacts of climate change on Australian alpine ecosystems, with a specific emphasis on trichopteran.

Ualani attained hands-on experience through an internship at the Centre for Freshwater Ecosystems, La Trobe University, building her skills in aquatic invertebrate identification, environmental DNA extraction and field data collection. Her research during her honours has earned her a City of Wodonga prize for her outstanding contribution to the environment.

With her keen interest in ecological management and science communication, Ualani aspires to pursue further studies or embark on a career in the environmental research sector. Outside of academia, she enjoys birdwatching, delicious cuisine, and exploring nature with friends.

Abstract:

The Australian Alps are a globally unique environment at the forefront of the most profound and substantial consequences of climate change. Australian alpine streams are increasing in temperature and are predicted to increase by 3℃ by the end of the century. As ectotherms, invertebrates are intrinsically linked with temperature; increases in temperature are known to drive changes in invertebrate development and size. This study contributes to our understanding of how climate change is impacting alpine streams and their aquatic invertebrate species. Endemic alpine caddisflies, Archaeophylax ochreus, were reared at four temperatures (9℃, 12℃, 15℃ and 18℃) to investigate their effects on time until pupation, pupation duration, and emergence times (full development).

This study found that individuals reared at the coolest temperature treatment took the least number of days and Cumulative Degree Days (CDDs) to reach pupation, indicating a different biological process such as diapause. Pupation duration decreased as temperature increased and could be quantified using CDDs. Full development was substantially influenced by time to pupation, and no difference in full development was found amongst treatments.

While changes in temperature do not appear to have a significant effect on timing of emergence for this species, warmer temperatures were found to reduce larvae survival rates. This study concludes that, while it is unlikely that increasing temperatures under climate change will have a substantial impact on timing of invertebrate influxes into the terrestrial environment, it will likely lead to an overall reduction of the biomass entering the terrestrial landscape.