Data from: Distributions of mammals in Southeast Asia: the role of the legacy of climate and species body mass

Aim: Current species distributions are shaped by present and past biotic
and abiotic factors. Here we assessed whether abiotic factors (habitat
availability) in combination with past connectivity and a biotic factor
(body mass) can explain the unique distribution pattern of Southeast Asian
mammals, which are separated by the enigmatic biogeographic transition
zone, the Isthmus of Kra (IoK), for which no strong geophysical barrier
exists. Location: Southeast Asia Taxon: Mammals Methods: We projected
habitat suitability for 125 mammal species using climate data for the
present period and for two historic periods: mid-Holocene (6 kya) and last
glacial maximum (LGM 21 kya). Next, we employed a phylogenetic linear
model to assess how present species distributions were affected by the
suitability of areas in these different periods, habitat connectivity
during LGM and species body mass. Results: Our results show that cooler
climate during LGM provided suitable habitat south of IoK for species
presently distributed north of IoK (in mainland Indochina). However, the
potentially suitable habitat for these Indochinese species did not stretch
very far southwards onto the exposed Sunda Shelf. Instead, we found that
the emerged landmasses connecting Borneo and Sumatra provided suitable
habitat for forest dependent Sundaic species. We show that for species
whose current distribution ranges are mainly located in Indochina, the
area of the distribution range that is located south of IoK is explained
by the suitability of habitat in the past and present in combination with
the species body mass. Main conclusions: We demonstrate that a strong
geophysical barrier may not be necessary for maintaining a biogeographic
transition zone for mammals, but that instead a combination of abiotic and
biotic factors may suffice.