Scale-area curves: a viable tool for managing invasive species

Scale-area curves have been used in conservation science as an affordable means of identifying shrinking populations that need protection. Invasions are the result of populations of invasive species that are spreading and becoming dominant in areas to which they have been introduced. As population growth is the opposite of population decline, it has been suggested that scale-area curves could be used to identify growing populations of species that may represent a future invasive threat.

In a recent paper published in the journal Biological Invasions, C·I·B researchers examined the idea of using scale-area curves for identifying key aspects of the ecology of emerging invasive species. Due to the substantial literature on Australian Acacia species, it was possible to use scale-area curves to explore differences in the population structure of two species that were introduced for different human uses and which currently occupy very different distributions.

The study showed that scale-area curves can identify “missing links” or gaps that are limiting the spread of invasive Acacia species. Many of these limitations appear to be linked to the reason for introduction with the human-modified landscape playing a role in the population structure. These gaps can be used to inform managers of the most appropriate management interventions. As such, the study showed that scale-area curves are a useful tool to use when looking for affordable ways of identifying the dimensions and components of invasive spread and how best to management particular invasive species.

Read the paper:

Donaldson, JE, Richardson, DM, Wilson, JRU (2014) Scale-area curves: a tool for understanding the ecology and distribution of invasive tree species. Biological Invasions 16: 553-563. DOI 10.1007/s10530-013-0602-0

For more information, contact Jason Donaldson at

Acacia elata and Acacia longifolia: focus species for this study

Acacia elata and Acacia longifolia were the focus species for this study. (a) Acacia elata was introduced throughout South Africa as an ornamental garden plant and has become invasive in areas close to suburban hotspots. (b) Acacia longifolia was introduced for dune stabilization along coastal mobile dune systems and has since spread from those original plantings.

Acacia elata spreading within a residential area

A population of Acacia elata, an ornamental tree spreading within a residential area. The study showed that the way in which trees were planted and the areas into which they were introduced had a substantial influence on the population structure of invasive trees.