When botanists who’ve been trying to collect seed for several years from an endangered plant get word that the plant is flowering, the opportunity is not to be lost. The particular plant is Aponogeton queenslandicus, a small aquatic plant known from only one location, an ephemeral swamp west of Bourke. It has a greenish yellow flower spike that emerges from the muddy swamp water when conditions are right.
Scientists do not know exactly what conditions this plant needs to flower, except that there needs to be water in the swamp. In 2020, after rain that broke the severe 2017-2020 drought, botanists from the Australian PlantBank (more about the PlantBank later) went to these ephemeral swamps near Bourke to search for this plant, hoping to collect seeds and some plant specimens. However, they found no trace of it!
In March this year, word came that the plant was in flower and the botanists from the PlantBank headed off again, collaborating with staff from the National Parks and Wildlife Service and other NSW government agencies. With the temperature at Bourke above 35 deg. C and the swamps drying up quickly, the team made their way through the muddy swamp water, sweltering in waders, to find the plants. This time, they managed to successfully collect seed and several plant specimens. They had found the holy grail!
Now that botanists have plant material from Aponogeton queenslandicus, they can carry out research to find the conditions it needs to germinate, flower and fruit and so hopefully give it some protection from future climatic changes, especially increasingly frequent and more severe droughts, which endanger its survival. Ultimately, with knowledge about the growing conditions it needs and available seed, other populations or plantings may be able to be established.
While this quest was successful, there are – unfortunately – many more holy grails for botanists to search for! Australia has around 24,000 species of native plants. Of those, about 1,400 (approximately 6 per cent) are listed as threatened to various degrees. We know very well the risks to survival these plants face, including land clearing, grazing by livestock and feral animals, attack by diseases and pests, competition from weeds, changed fire regimes and the effects of climate change, such as altered temperature and rainfall patterns. None of these factors is getting less severe!
Botanists are continuing their efforts to protect Australia’s native plant species from going extinct. This is where the Australian PlantBank comes in. It’s a major NSW centre of plant conservation research and a storage facility for plant propagation material in the Australian Botanic Garden at Mount Annan. The seed and plant tissue stored there provide insurance against native plant species becoming extinct. You can go on a tour of the PlantBank every Friday to Sunday.
Collecting plant material from threatened species is clearly very costly. How do PlantBank scientists prioritise what plants to collect? Some of the interrelated factors that would give a plant a high priority are:
- whether it occurs in areas where there are “boom” and “bust” periods that depend on climate;
- whether it occurs in very few locations and so has a high risk of extinction;
- whether scientists know very little about how it germinates, reproduces and disperses.
How difficult it can be to collect material from threatened plant species was summed up by Ruby Paroissien, Seedbank Officer at the Australian PlantBank, who was part of the team that travelled to Bourke: “To collect from species like Aponogeton queenslandicus, you must be in the right place at the right time. If we miss it, we may not see if for another 20 years.”
Source article: The holy grail: Scientists collect seeds from rare aquatic plant
by Nathan Emery. 2nd May, 2024.