Under pressure: Why are ecological communities under threat and what's being done to help them?
While you may know several species of native plants and animals under threat, did you know that ecological communities can be classified as threatened too?
By definition, an ecological community is a naturally occurring and interactive group of native plants, animals and other organisms that live in the same location. By studying the group as a collective, scientists, ecologists and citizen scientists can gain a better understanding of how the species benefit from their relationships with each other.
When a large proportion of an ecological community is lost through threatening processes like habitat damage or destruction, scientists can apply for it to be listed as ‘threatened’ under the National Environment Protection and Biodiversity Conservation Act. In this instance, each plant, animal or fungi in that ecosystem is treated as threatened and is legally protected, even if it is otherwise common elsewhere.
In this blog, we look at 2 threatened ecological communities in the Murraylands and Riverland region and explore why they are under threat, and what’s being done to try and help them recover.
Once abundant in South Australia, Iron-grass Natural Temperate Grasslands (INTG) were attractive to the first European settlers, offering year-round grazing for livestock. Overgrazing, and the conversion of grasslands for cropping, virtually decimated this ecosystem and today only 1% of the original area of INTG remain.
As diverse as a rainforest, INTG are dominated by 2 species of iron-grass - scented iron-grass (Lomandra effusa) and hard mat-rush (Lomandra multiflora ssp. dura) - both of which are members of the asparagus family. These grasslands also feature a mix of shrubs, lilies, grasses and wildflowers including herbs and orchids. Iron grasses are the largest plants in iron-grass grasslands and act as the skeleton of the ecosystem. As a spiky, tufted plant they provide crucial habitat in an exposed and treeless ecosystem, trapping and protecting seeds during droughts – leading to natural restoration when the rains come. There is a misconception that the iron-grass plants themselves are endangered but this is not the case. Iron-grasses are found in other ecosystems, including woodlands and mallee.
Like many native grasslands, iron-grass natural temperate grasslands are carbon sinks with healthy nitrogen and carbon cycling, and provide habitat to insects, birds, reptiles, bats and fungi. They live for hundreds of years and are adapted to persevere through varying weather conditions, including droughts and fire.
Since 2018, the Murraylands and Riverland Landscape Board has worked with landholders, surveying more than 56,000 hectares of iron-grass grassland country. Ten long-term monitoring sites have been set up to monitor vegetation health over time and, in conjunction with First Nation’s communities, we’re also undertaking grazing trials and a Yarluwar Ruwe assessment.
Over the next few years, landscape ecologists will continue to work with landholders and the community to protect the last remaining areas of iron-grass grasslands. By reducing the impacts of pest animals and plants and the effects of overgrazing, this remarkable and unique ecological community will remain for generations to come.
Find out more about Iron-Grass Natural Temperate Grasslands.
The Mallee Bird Threatened Ecological Community is a group of 21 native birds that were traditionally found in mallee ecosystems across south east Australia. In the Murraylands and Riverland region, the largest expanse of mallee exists in the South Olary Plain, a vast landscape to the north of the Riverland.
For a greater part of the 20th century, this land was used to graze livestock, and the effects of grazing altered the way that local ecological communities existed. Contributing to overgrazing, a network of man-made dams was created to provide livestock with year-round water. Although sheep are long gone from this part of the South Olary Plain, other herbivores including rabbits, goats and kangaroos persist in unsustainable numbers because of these water points, putting significant pressure on surrounding vegetation. This has impacted on food and habitat for birds, resulting in declines in many of the species that comprise the Mallee Bird Threatened Ecological Community.
Over the past 5 years, the landscape board’s landscape ecology team has been working in partnership with like-minded organisations to help improve the health of South Olary Plain landscapes. A number of the dams have been filled in with earthmoving machinery to prevent overgrazing of local vegetation by animals attracted to the watering point. Despite being in the early days of recovery, landscapes are quickly showing encouraging signs with new shrubs and trees emerging, and numbers of grazing animals reducing to more sustainable levels.
To find out more about the restoration of the South Olary Plain, read our blog post Breathing New Life into Little Oak Dam.
The Irongrass Natural Temperate Grasslands project is supported by the Murraylands and Riverland Landscape Board with funding from the landscape levies. Restoring Functionality to the South Olary Plain is supported by the Murraylands andRiverland Landscape Board with funding from the Landscape Priorities Fund.
