Emma Sumner has recently completed her honours under John Morgan with the RCAAE at La Trobe University. Emma studied the biotic and abotic factors that affect local distributions of a model alpine plant, Alpine Podolepis (Podolepis robusta). This was investigated using various field and laboratory experiments designed to understand what controls the local distribution of this plant.
Emma found that Alpine Podolepis has a far greater fundamental niche than is currently realised at Mt Hotham, with facilitative interactions playing a strong role across range edges. A transplant experiment along a temperature and moisture gradient found that close interspecific neighbours significantly increased survival and growth of planted seedlings, compared with seedlings planted in canopy gaps. This pattern was found to be consistent, even below the current distribution of Alpine Podolepis where it was expected that close interspecific neighbours would result in stronger competitive interactions.
Emma’s thesis highlight the importance of facilitative interactions at the seedling stage in the alpine zone, demonstrating that biotic factors act to constrain or widen the theoretical niche. Emma argues that biotic interactions, dispersal limitation, and recruitment processes may enforce stronger limits to geographic distribution than climatic tolerances per se and that predictions on how plant species may respond to climate change would benefit from incorporating these factors.
Two new Honours students have recently joined the RCAAE under the supervision of Dr John Morgan and Dr Susanna Venn.
Lauren is investigating the potential for alpine herbs and grasses to disperse. Currently there is almost no field data on seed dispersal, but it is an important research topic given the need for species to disperse to track their changing climate envelope. Using a series of novel seed traps (that capture seeds dispersing at 30 cm and 1.8 m above the ground), she will quantify seed rain and the seed traits that help predict dispersal.
Aviya is investigating long-term change in alpine and sub-alpine treelines in the Bogong High Plains area. Treelines are susceptible to movement as climate warming occurs, but there have been no recent assessments of this phenomenon in Australia. Using permanent transects established in 1999-2002, she will examine evidence for treeline movement and how recent fires have impacted on the position of the treeline.
Left photo: Lauren testing her novel seed traps at Falls Creek. Right photo: Aviya and supervisor John Morgan examining treelines on the Bogong High Plains.
John Morgan & Susanna Venn have modelled the dispersal capacity of most of the alpine flora of Kosciuszko (198 species). They found that most species are predicted to have short-distance dispersal (<10m). This highlights the limited ability of Australian alpine flora to disperse and track rapid climate change.
Morgan, J. W., & Venn, S. E. (2017). Alpine plant species have limited capacity for long-distance seed dispersal. Plant Ecology, 218(7), 813-819.
The RCAAE recently hosted a National Expert Elicitation Workshop at La Trobe University (19-21 June 2017) examining the adaptive capacity and functional importance of alpine flora in the face of climate change.
Lead by an expert elicitation facilitator (Anca Hanea, University of Melbourne), workshop participants scored a range of alpine species for their present (2017) and future (2050) vegetative cover, a surrogate for functional importance and adaptive capacity. Participants also began the process of assembling a long-term alpine plot database that could be used to track change in species distribution and cover.
The Research Centre for Applied Alpine Ecology and two of its members, Dick Williams and John Morgan, recently featured in an article in TERN Newsletter (June 2017) announcing that 70-years of long-term monitoring data are now available online via the TERN Data Discovery Portal.
Data supplied by the Research Centre for Applied Alpine Ecology covers 70-years of data from Victorian Alpine Plot Network which has captured a long history of the sites’ vegetation and ground cover condition change, represented by an exceptionally diverse set of population-related observations totaling over 200,000 records.
This data is not only increasing our understanding of impacts such as fire, grazing and exotic species invasions, but also informing land-management decisions by government agencies and private enterprise and helping document a small but important part of the Alps’ natural heritage.
Article in TERN Newsletter, June 2017