The potential distribution of Chiranthodendron pentadactylon (Malvaceae)
through time: Phylogeography revisited and predicted environmental
suitability under alternative future climate change scenarios.
Abstract
Aim: Mexican hand tree Chiranthodendron pentadactylon is an evergreen
temperate tree species restricted to cloud forests and pine-oak forests
of southern Mexico, Guatemala and possibly Honduras. Climate is believed
to significantly contribute to the species establishment, viability and
distribution. Insights into the impact of climate change on the species
potential distribution throughout time were approached by ecological
niche modeling tools. Location: Southern Mexico, Guatemala and Honduras.
Methods: Past (Last Interglacial 120-140 KA, Last Glacial Maximum 22 KA,
Mid-Holocene 6 KA), historical (1910-2009) and future (2021-2040,
2041-2060, 2061-2080 and 2081-2100) potential distributions and
corresponding environmental suitability were modelled using the Maximum
Entropy algorithm. Current (historical) models were based on the most up
to date historical environmental variables and constituted the baseline
for past and future projections. Past predictions are revisited in a
phylogeographic context. Future predictions were made for four different
emissions scenarios. Results: Increase in potential distribution range
comes about during cold and humid periods but higher suitability
possibly relates to humid conditions. Potential distribution alongside
environmental suitability diminishes during warm and dry periods. Future
climate change implies warmer periods whence environmental suitability
declines following a linear trend. Main conclusions: Future warmer
conditions are predicted to linearly reduce environmental suitability
throughout time. Biotic and anthropogenic factors further threaten the
species distribution. Demographic trends and genetic diversity estimated
through a recent phylogeographic study, complement the statement that
populations viability is increasingly being threatened by current and
future climate change, underscoring the need for the implementation of
conservation actions.