Developing a screening tool to determine the impact of climate change on seed germination in threatened native plant species – Progress Report

Progress report on the grant:

Philip Ainsley and Jenny Guerin, Botanic Gardens of Adelaide

December 2009

Funding was awarded to the Botanic Gardens of Adelaide to determine if it is possible to develop a screening tool to identify threatened plant species that maybe impacted by environmental changes associated with climate change, using seed germination as an indicator.

The project is now well underway at the South Australian Seed Conservation Centre (Botanic Gardens of Adelaide), and on track in accordance with the work schedule that was provided in the grant application. Additional funding to assist with delivery of the project has been secured through the Native Vegetation Council (South Australia).

Over the last 12 months the following objectives have been achieved:

• A list of threatened plant species identified as being at potential risk form the impact of climate change was developed. A range of plant forms (trees, mid-storey and understorey species) were included to cover a diverse representation of plant forms and vegetation profiles. Two key criteria were used to identify plant species for the research project. The criteria were:
o listed as threatened (endangered, vulnerable and/or rare) under the South Australian National Parks and Wildlife Act, 1972;
o limited distribution within a submontane environment (the focus for this project).

• During the 2008/2009 seed collection season, 14 species (Table 1) were located in their native environment and had seed of a suitable quantity and quality (deemed as viability > 75%) collected and made available for the project.

TABLE 1: Species collected for research project

Genus Species Rating† Plant Form Collection Region
*°Acacia gunnii Rare Shrub Mount Lofty Ranges
*°Acacia spooneri Rare Shrub Southern Flinders Ranges
Billardiera uniflora Uncommon Climber Mount Lofty Ranges
*°Brachyscome diversifolia Endangered Forb Mount Lofty Ranges
*°Derwentia decorosa Rare Forb Southern Flinders Ranges
*°Derwentia derwentiana ssp
Endangered Forb Mount Lofty Ranges
*°Eucalyptus dalrympleana Rare Tree Mount Lofty Ranges
*°Eucalyptus globulus ssp
Vulnerable Tree Mid North
*°Festuca benthamiana Rare Grass Southern Flinders Ranges
*°Oreomyrrhis eriopoda Endangered Forb Mount Lofty Ranges
*°Pultenaea graveolens Uncommon Shrub Mount Lofty Ranges
°Veronica gracilis Vulnerable Forb South East
°Veronica parnkalliana Endangered Forb Southern Flinders Ranges
°Wurmbea uniflora Endangered Forb Mount Lofty Ranges

†Rating as per the South Australian National Parks and Wildlife Act, 1972

• Seed embryos have been located and classified for all 14 species, and provided useful information in determining what treatments would be tested to promote germination.

• Testing of germinability has been initiated for all 14 plant species, and methods including seed coat scarification, cold/warm stratification, dry after-ripening and the use of chemicals (gibberellic acid, potassium nitrate and smoked water) to facilitate germination rates greater than 75% within 6 weeks have been developed for 10 of the collected species (indicated by * in Table 1). Germination research is on-going for the remaining 4 species.

• Research experiments to generate temperature profiles using a purpose built thermogradient plate testing a range of constant temperatures along a temperature gradient with a lower limit of 5°C and upper limit of 40°C are nearing completion. Profiles collecting data on germination rate, frequency and seedling vigour have been completed for 13 species to date (indicated by ? in Table 1). Different germination trends were observed for different species, with some species able to germinate over a wide range of temperatures, whilst others were much more specific.

• Experiments using the thermogradient plate in ‘2-way’ mode have commenced. This will allow a range of diurnal temperature combinations (between 5 and 40°C) to be tested, and determine if testing static temperatures is sufficient to identify species with a narrow climatic envelope relating to germination temperature.

• The modelling component of the project will be undertaken on completion of the germination research.

• Expenditure of grant money: The first instalment ($5,175) has been fully expended, being used towards the salary of the seed research officer (Dr Jenny Guerin) to run the experiments.

Dr Phil Ainsley Dr Jenny Guerin
Manager, SA Seed Conservation Centre Seed Research Officer
6.i.2010 6.i.2010