Bogong Moth Aestivation Sites as an Archive for Understanding the Floral, Faunal and Indigenous History of the Northern Australian Alps

The research detailed in this dissertation focuses on plant and faunal remains preserved in the accumulating sediments at aestivation sites of the Bogong Moth (Agrotis infusa), in the crevices of granite tors in the northern Australian Alps. Analyses have confirmed the preservation of a diverse range of fossil material, including bird feathers, hairs of small marsupials occupying the rock crevice niche, fossil pollen and spores derived from the summit vegetation, and charcoal from fires in the immediate vicinity of the aestivation sites. The fieldwork focused on the sampling of deposits at various aestivation sites representative of different biogeographical areas to ascertain the sedimentary characteristics of each region. Three aestivation study areas were located and sampled for the study, the Brindabella Ranges, the Bogong Peaks and the Tinderry Range in NSW. The Tinderry Range sites represent the most easterly geographical region, while the Bogong Peaks site and Brindabella Ranges sites represent, respectively, the western and central aestivation site regions of the northern Australian Alps area. Since preservation of organic material typically occurs in a stable low oxygen environment, investigation into the depositional environment is an important aspect of the study to taphonomically contextualise the environmental proxies. The palynological preparation of material from the three regions revealed abundant pollen derived from local vegetation. A rich assemblage of mammal hair was found in the Bogong Peaks and Mt Gingera sediments. This record provides a unique faunal proxy of sub-alpine ecosystems. Levels of charcoal in the sediments reflect past fire frequency, and are presented in both micro- and macro-charcoal graphs. Aestivation site deposits are a unique terrestrial archive recording ecological change in the montane and sub-alpine environments for over 1000 years. Despite some chronometric difficulties, they provide an excellent record of the effects of local disturbance, such as fires, on the biome and provide insights into the impact of European settlement, on both vegetation structure and faunal biodiversity. The study provides evidence of massive cultural, ecological and climatic upheaval at sub-alpine elevations in the northern Australian Alps from the late Holocene up to the present, and illustrates the great value that aestivation sites hold as terrestrial archives, signalling a need for further utilisation and investigation in light of rapid human induced climate change

Endangered Bogong moths (Agrotis infusa) forage from local flowers after annual mass migration to alpine sites

Migration plays an important role in the life cycle of many insect species, allowing them to escape unfavourable seasonal conditions. The Bogong moth (Agrotis infusa) is a keystone species that undertakes a long-distance annual migration, with billions of individuals aestivating in summer in the Australian Alps. This species has undergone drastic population declines in the past five years, with steady long-term declines also recorded since the 1980s, and has recently been recognised as Endangered by the IUCN. Despite the role of Bogong moths as a keystone species in the Australian sub-alpine and alpine zones, their feeding habits during their time in the mountains remain understudied, although earlier research suggested that they do not feed during their summer aestivation. To examine whether Bogong moths visit flowers during the summer, we collected pollen from moths caught at a high elevation site in the Australia Alps over the 2021/22 summer period and then identified and counted pollen using light microscopy. We show for the first time that Bogong moths visit a broad range of plant species during their summer activity period and characterise the plant assemblage visited. Almost all the 129 moths sampled carried pollen in large quantities, with a mean of 521 grains per moth. Individual moths varied considerably in pollen load and species composition, suggesting generalist flower visitation. The pollen taxa present on moths indicates local flower feeding at high elevation sites, rather than pollen carried from the lowland origins of migrants. The presence of pollen throughout summer indicates continual flower feeding activity. These results provide important new insights into the ecology of Bogong moths and suggest they could play a previously unrecognised role in pollination in sub-alpine and alpine ecosystems

The AusPollen partnership project: Allergenic airborne grass pollen seasonality and magnitude across temperate and subtropical eastern Australia, 2016–2020

Background: Allergic rhinitis affects half a billion people globally, including a fifth of the Australian population. As the foremost outdoor allergen source, ambient grass pollen exposure is likely to be altered by climate change. The AusPollen Partnership aimed to standardize pollen monitoring and examine broad-scale biogeographical and meteorological factors influencing interannual variation in seasonality of grass pollen aerobiology in Australia. Methods: Daily airborne grass and other pollen concentrations in four eastern Australian cities separated by over 1700 km, were simultaneously monitored using Hirst-style samplers following the Australian Interim Pollen and Spore Monitoring Standard and Protocols over four seasons from 2016 to 2020. The grass seasonal pollen integral was determined. Gridded rainfall, temperature, and satellite-derived grassland sources up to 100 km from the monitoring site were analysed. Results: The complexity of grass pollen seasons was related to latitude with multiple major summer-autumn peaks in Brisbane, major spring and minor summer peaks in Sydney and Canberra, and single major spring peaks occurring in Melbourne. The subtropical site of Brisbane showed a higher proportion of grass out of total pollen than more temperate sites. The magnitude of the grass seasonal pollen integral was correlated with pasture greenness, rainfall and number of days over 30 °C, preceding and within the season, up to 100 km radii from monitoring sites. Conclusions: Interannual fluctuations in Australian grass pollen season magnitude are strongly influenced by regional biogeography and both pre- and in-season weather. This first continental scale, Southern Hemisphere standardized aerobiology dataset forms the basis to track shifts in pollen seasonality, biodiversity and impacts on allergic respiratory diseases.</p