Flora

Arid plants are exceptionally well adapted to survive the harsh desert, surviving in nutrient-poor soils, minimal rainfall, and sweltering temperatures

Certain desert plants, like the bluebushes and mulga trees, live in life in the slow lane, taking a  leisurely pace of growth to survive the arid conditions. On the other hand, vibrant annual flowers prefer to live fast and die young. They bloom quickly and produce seeds while the favorable conditions last, living a short but vibrant existence

Arid Recovery is in the driest state in the driest continent in the World, with an average annual rainfall of ~160 mm. The reserve features mainly long sand dunes covered with sandhill wattle (Acacia ligulata), slender-leaved hopbush (Dodonaea viscosa), and various grasses. Between the dunes, you'll find a variety of chenopod plants, including bladder saltbush (Atriplex vesicaria) and low bluebush (Maireana astrotricha).

Arid Recovery boasts a diverse range of plant species, with over 250 identified. Among them is the endangered Atriplex kochiana. The majority of these species are annuals that remain dormant in the seedbank until a rainfall event. Summer showers trigger the growth of annual grasses, while ample winter rains lead to an abundance of wildflowers, such as the poached egg daisy (Polycalymma stuartii), and sturt desert pea (Swainsona formosa).

After the rain, a sea of poached egg daisies appears amongst the chenopods

What has Arid Recovery learnt?

Our reintroduced species are master gardeners 

The greater bilby, burrowing bettong, and Shark Bay bandicoot dig for insects, roots, tubers, and seeds, leaving the ground pockmarked with their diggings. These mini composting holes collect water, nutrients, and seeds. Researchers at Arid Recovery discovered that bilby diggings contain over twice the soil carbonand  significantly more nitrogen  than surface soil. These diggings create a favorable microclimate for seed germination, with a germination rate three times higher than that of rabbit diggings or surface soil. Often called ecosystem engineers, bilbies help regenerate plants by transforming the landscape through their digging and foraging activities. Reintroducing bilbies and other soil-disturbing mammals back to the area supports the natural regeneration of local flora.

Overabundant native herbivores affect native vegetation 

Vegetation recovery at Arid Recovery proved to be more complex than just removing rabbits and reintroducing native mammals. Ten years after burrowing bettongs were reintroduced to the reserve, their population significantly increased. These generalist herbivores can consume most plant species at the reserve. Consequently, some palatable plant species, such as ruby saltbush (Enchylaena tomentosa), became increasingly rare as the bettong population boomed. The recruitment of new seedlings for mulga and callitris stalled, and other plants like the native plum (Santalum acuminatum) suffered from overbrowsing.

To stabilise the bettong population, the western quoll was introduced to the reserve as a native predator. This has reduced the bettong population to a more sustainable level. We are optimistic that our ongoing monitoring program will begin to show positive changes in plant cover and diversity as vegetation recovery resumes.
From left to right: native plum with its bark stripped from bettongs, wattle seetling damaged by bettongs, and a burrowing betong

The removal of introduced predators has had other impacts on vegetation. Native rodents, such as spinifex hopping mice (Notomys alexis), have thrived within the safety of the fence, reaching densities more than 15 times higher than those outside the reserve. These rodents, along with the numerous bettongs, dig through the sand for seeds, altering the vegetation structure. As a result, the dunes inside the reserve are less shrubby than those outside, where the high mammal populations have depleted the seed bank and reduced shrub germination.