Cajanus mareebensis Population Modelling

When the Department of Transport and Main Roads reported several records of the endangered species Cajanus mareebensis within the footprint of their road sealing works area on the Peninsula Developmental Road (PDR) in Cape York, they called on Biotropica Australia to assist them in the management of the plant.

  1. mareebensis is protected as an endangered species under both the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and the Nature Conservation Act 1992 (NC Act). The distribution of this species was not well known and the unobtrusive life form (small ground dwelling vine), together with the frequency and abundance at which it was recorded within the proposed development areas of the PDR, suggested that it was more common than previously thought.

Biotropica Australia was commissioned to complete a predictive habitat distribution modelling exercise using computer algorithms to predict the distribution of the species in geographic space on the basis of a mathematical representation of their known distribution. Biotropica botanists used the initial predictive model to guide a targeted field based survey to confirm the on-ground extent of the species population.  The results of the field survey were used in an iterative process to further refine the proposed distribution model.  The finalised model was used to complete an assessment of predicted impact of the TMR works and formed the basis of an application to downgrade the legal protection of this species based on the known greater population.