Predicted declines in suitable habitat for greater one-horned rhinoceros
(Rhinoceros unicornis) under future climate and land use change
scenarios
Abstract
Aim Rapidly changing climate is likely to modify the spatial
distribution of both flora and fauna. Land use change continues to alter
the availability and quality of habitat and further intensifies the
effects of climate change on wildlife species. We used an ensemble
modelling approach to predict changes in habitat suitability for an
iconic wildlife species, greater one-horned rhinoceros due to the
combined effects of climate and land use changes. Location Nepal.
Methods We compiled an extensive database on current rhinoceros
distribution and selected nine ecologically meaningful environmental
variables for developing ensemble models of habitat suitability using
seven different species distribution modelling techniques in the BIOMOD2
R package; and we did this under current climatic conditions and then
projected them onto two possible climate scenarios (SSP1-2.6 and
SSp5-8.5) and two different time frames (2050 and 2070). Results Out of
seven algorithms, random forest performed the best, and four
environmental variables — distance from grasslands, distance from
wetlands, annual precipitation, and slope, contributed the most in the
model. The ensemble model estimated the current suitable habitat of
rhinoceros to be 1,875 km2, about 1.3% of the total area of Nepal. The
future habitat suitability under the lowest and highest emission
scenarios was estimated to be: (1) 1,637 km2 and 1,417 km2 in 2050; and
(2) 1,562 km2 and 1,301 km2 in 2070, respectively. Main conclusions Our
results suggest that nearly one-third of the current rhinoceros habitat
would become unsuitable within a period of 50 years, with the predicted
declines being influenced to a greater degree by climatic changes than
land use changes. We have recommended several measures to moderate these
impacts, including relocation of the proposed Nijgad International
Airport given that a considerable portion of potential rhinoceros
habitat will be lost if the airport is constructed on the currently
proposed site.