Potential distribution prediction of Amaranthus palmeri S. Watson in China under current and future climate scenarios

The vicious invasive alien plant Amaranthus
palmeri poses a serious threat to ecological security and food
security due to its strong adaptability,
competitiveness, and herbicide resistance. Predicting its potential
habitats under current and future climate change is critical for
monitoring and early warning. In this study, we used two sets of climate
data, namely, WorldClim1.4 and RCPs (the historical climate data of
WorldClim version 1.4 and future climate data of RCPs), WorldClim2.1 and
SSPs (the historical climate data of WorldClim version 2.1 and future
climate data of SSPs), to analyze the dominant environmental variables
affecting the habitat suitability and predict the potential distribution
of A. palmeri to climate change in China based on the
MaxEnt model. The results show that (i) Temperature has a greater impact
on the distribution of A. palmeri. The relative contributions of
temperature-related variables count to 70 % or more, and the annual mean
temperature (bio1) reached more than 40 %. (ii) At present, the
potentially suitable area is widely distributed in the central-east and
parts of southwest China, and the high suitable area is focused on the
North China Plain. The potential suitable area predicted by
WorldClim1.4 and WorldClim2.1 both accounts for about 31% of China's
total land area. (iii) Future climate change will expand the suitable
habitats to high latitudes and altitudes. The overall suitable area
maximum increased to 44.93% under SSPs and 38.91% under RCPs. We
conclude that climate change would increase the risk of A.
palmeri expanding to high latitudes and altitudes, the results
have practical implications for the effective long-term management in
response to the global warming of A. palmeri.