Native plant species are reclaiming their territory as they bounce back in habitats that we’ve disturbed. This is the heartening finding from University of New South Wales researcher, Ms Susan Everingham.
Ecologists have mostly investigated the impact of introduced species that invade natural ecosystems, but Susan Everingham, a PhD candidate at the Evolution and Ecology Research Centre, University of New South Wales, has turned invasion biology upside down. She is interested in which native plants can grow in areas that have been affected by human activity. She surveyed different regions of New South Wales to determine which types of native species could colonise disturbed habitats – from urban nature strips and road shoulders, to railway embankments, to fire trails in bushland.
Ms Everingham found a number of native species among the many non-native plant species present in all areas. More native plants were found in less disturbed habitats, such as fire trails. Greater urbanisation reduces the number of native species present. The native plants found in highly urban areas (on nature strips and off roads) are shorter, and have small seeds and faster life cycles, such as grasses and shrubs.
‘The survival of these smaller plants is a stepping stone for other plants, such as taller, native trees to get in there. Over time, there could be more recruitment and growth of native plants,’ said Ms Everingham. Although most plants in highly disturbed areas were smaller plants, such as grasses, she still found some seedlings of larger trees, leaving hope that they might come back too.
In over 200 years since European settlement, there have been significant changes to the way native vegetation is managed. Clearing for agriculture and urban development, and the introduction of non-native plant species have drastically affected the survival of many of our native species. The depletion and degradation of native vegetation ecosystems threaten the long-term health of Australian landscapes.
The presence of native plants in our ecosystems increases biodiversity and reduces invasion by non-native species. Native vegetation in urban areas is also essential for the conservation of native pollinators, and small native mammals and birds that may otherwise become endangered.
‘Population growth has increased, and is predicted to increase into the future. We’re clearing more land to build more cities, roads and infrastructure. The disturbance to natural habitats can have a detrimental impact on native species.’
Ms Everingham’s study has launched a new area of research for ecologists – because if some native species can pop up in urban areas, perhaps we may see an increase in others too. With the pressure of a growing population, we can’t stop building infrastructure to support it. We therefore have to think of other solutions to protect Australian landscapes and biodiversity. ‘As we create more disturbed environments, knowing which native plants can adapt to living in urban areas is important for informing decisions about how we design the ecosystems that we live in’.
Ms Suz Everingham recently published her findings in the Journal Austral Ecology.