Article by James Bevan
Plant species which establish after environmental disturbances events are known as “colonisers” or colonising plant species. Following 2019-20 summer bushfires and floods, colonising plants are germinating from seed into the ground layer vegetation stratum. These autotrophic organisms (which produce their own energy as carbon from photosynthesis) are currently superabundant, capturing carbon for ecological communities across the Blue Mountains. This process is known as secondary ecological succession.
The below photo shows a local example of secondary ecological succession dominated by ground layer species Sigesbeckia orientalis and Australian Basket Grass (Oplismenus aemulus).
Interestingly, many colonising plant species are related members of certain plant families, such as the Grasses (Poaceae), Daisies (Asteraceae), Nightshades (Solanaceae), Peas (Fabaceae), and Mints (Lamiaceae). Some of the colonising species which are currently abundant post-fire and rain are listed in the Table below (Table 1).
Table 1: Examples of Colonising Plant Species
|Poaceae (Grasses)||Right Angle Grass, Wiry Panic (Entolasia marginata)|
|Poaceae (Grasses)||Weeping Grass (Microlaena stipoides)|
|Poaceae (Grasses)||Australian Basket Grass (Oplismenus aemulus)|
|Poaceae (Grasses)||*Panic Veldtgrass (Ehrharta erecta)|
|Asteraceae (Daisies)||Sigesbeckia orientalis|
|Asteraceae (Daisies)||*Fleabane (Conyza spp.)|
|Solanaceae (Nightshades)||Kangaroo Apple (Solanum aviculare)|
|Solanaceae (Nightshades)||*Blackberry Nightshade (Solanum nigrum)|
|Fabaceae (Peas)||Hickory Wattle (Acacia falcata)|
|Fabaceae (Peas)||Dusky Coral Pea (Kennedia rubicunda)|
|Fabaceae (Peas)||*Scotch Broom (Cytisus scoparius)|
|Lamiaceae (Mints)||Cockspur Flower (Plectranthus parviflorus)|
Practical Application – Revegetation
Planted colonising species often have high survivorship rates on revegetation sites. Succession planting describes using colonising plant species during the first stage of revegetation, similar to the process of ecological succession. As our climate continues to change, plantings can expect to be exposed to extreme heat, longer summers and long periods between rain events. Planting colonising plant species with a high survivorship and fecundity may improve the efficiency of long-term ecological restoration.
For example, widely distributed native colonising species that may be suitable for revegetation include Right Angle Grass (Entolasia spp.), Weeping Grass (Microlaena stipoides), Australian Basket Grass (Oplismenus aemulus), Sigesbeckia orientalis, Kangaroo Apple (Solanum aviculare), Hickory Wattle (Acacia falcata), Dusky Coral Pea (Kennedia rubicunda) and Cockspur Flower (Plectranthus parviflorus). The ecological communities found on your local Bushcare site will support locally adapted colonising plant species. Your local Bushcare Officer may be a good source of further advice on this topic.