Predicting future distribution patterns of Jatropha gossypiifolia L. in South Africa in response to climate change

Abstract

Invasive alien species such as Bellyache bush (Jatropha gossypiifolia L.) pose immense threats to global food security, biodiversity, ecosystem integrity and provision of ecosystem services. The Bellyache bush has generally been naturalised in Africa but poses vast management challenges in the African Savannah, yet there is little knowledge of its spatial distribution and future potential invasion risk.

In this study, we modelled the spatial distribution of Bellyache bush in South Africa as a function of key biophysical factors using maximum entropy (MaxEnt) and estimated its potential invasion risk into native environments because of climate change.

Results show that temperature seasonality, mean annual temperature range and mean temperature of the coldest month are the key factors explaining Bellyache bush distribution in South Africa.

The response of the occurrence of Bellyache bush to the temperature variables demonstrated that the suitable habitat for Bellyache bush ranged between 10° and 30 °C while the tolerance to precipitation range is very wide (400 mm – > 2500 mm/year−1). The total area suitable for Bellyache bush propagation in South Africa is ∼129 034 km2 (10% of the total land area of South Africa) in the current and will increase because of climate change to ∼510 914 km2 (40% of the total land area of South Africa).

Our results suggest that we can estimate the spatial distribution and Bellyache bush invasion risk areas in South Africa. This implies that policies and management strategies for further Bellyache bush invasions in South Africa can now informatively be targeted to high priority areas.