1. Introduction
Over the years, global ecological changes and environmental devastation
triggered by human-induced activities and climate alteration have
increased globally (Ofori et al., 2017;
Measey et al., 2019). We are now facing
enormous pressures that are driving geographic distribution patterns of
plants and animals (Behroozian et al.,
2020; Gainsbury, 2020), altering
ecological community structure (Zhou et
al., 2017), and impacting ecosystem stability
(Karimi et al., 2021). Such threats have
led to significant animal migration, extinction, and population
reduction in the Quaternary (Chen et al.,
2011; Hoffmann and Sgrò, 2011),
resulting in more than 75% alteration in contemporary terrestrial
ecosystems (Venter et al., 2016),
following extensive agricultural changes and deforestation
(Gries et al., 2019), and accelerated
expansion of urbanization (Eötvös et al.,
2018; Duncan et al., 2020).
Thus, ecological changes and human-induced activities during the
Quaternary, which have remarkably caused climate changes and faunal and
floral geographic alterations, have created unprecedented biodiversity
diminishing and conservation pressures
(Worm et al., 2006;
D’Agata et al., 2016). Changes in
species’ geographical range result in compelled migration towards
suitable habitats, while some species that cannot respond rapidly are
pushed to extinction (Radchuk et al.,
2019; Doherty et al., 2021). Such as,
mountain lions (Puma concolor ) exhibited significant
antipredatory behavior changes in response to habitat alteration,
resulting in a 34% reduction in their distribution
(Suraci et al., 2019), forcing them to
abandon high-risk home ranges (Schuette et
al., 2013). Following global warming, glaciers, and sea ice melting
rapidly, the population of polar bears (Ursus maritimus ) at the
southernmost end of the Arctic region has declined sharply
(Derocher et al., 2004). Such combined
impacts in the 21st century and beyond will further
alter animals’ distribution, causing the extinction of many wildlife
species in the Sixth Mass Extinction
(Struebig et al., 2015;
Gouveia et al., 2016). Such phenomenon
especially applies to
non-human
primates, who are more sensitive to those changes and entirely dependent
on forested ecosystems (Estrada et al.,
2017; Zhang et al., 2019b). That is why
over 60% of extant global species are on the edge of extinction
(Estrada et al., 2017;
Carvalho et al., 2019). Regarding the
situation in mainland East Asia, such a scenario is even more gloomy –
approximately 80% of the 28 primate species are threatened
(Li et al., 2018).
The macaques
(Macaca )
in the subfamily Cercopithecinae have 23 species in Africa and Asia
(Roos et al., 2019). Their dispersal
scenarios from Africa to Asia were driven by the environmental changes
in the Miocene (Zinner et al., 2013;
Roos et al., 2014;
Zhang et al., 2022): they originated in
Africa and started the migration to Europe and Asia following the
collision of the Afro-Arabian plate with Eurasia during the
Oligocene-Miocene (23.8-18 Mya), which created a land connection between
Arabia and Southwest Asia, making many animal taxa migrated from Africa,
via Europe, to Asia since the Miocene
(Roos and Zinner, 2015), including
macaques. In other words, macaques’ evolutionary development and
distribution patterns have been remarkably driven by climate,
ecological, and geographic changes since the Miocene, except for the
Barbary macaques (Macaca sylvanus) left in North Africa. The
other macaque taxa finally settled down in Southwest China during the
Pliocene. They continued distributing to East and South Asia through
alternative dispersal paths during the Quaternary
(Li et al., 2020;
Zhang et al., 2022). Eight extant
species are now distributed in mainland East Asia: rhesus macaques
(Macaca mulatta ), the northern pig-tailed macaque (M.
leonina ), the stump-tailed macaque (M. arctoides ),
Formosan rock macaque (M. cyclopis ) in Taiwan, Assamese macaque(M. assamensis ), the Tibetan macaque (M .thibetana ), the Arunachal macaque (M. munzala ), and the
white-cheeked macaque (M. leucogenys ). They are classified
as Class Ⅱ or Ⅰ of Nationally Protected Wildlife in China and are
included on the IUCN Red List of threatened species
(IUCN, 2022). Over the past two
millennia, global climate change and human activities (including
dramatic population explosion and resource depletion, agricultural
expansion, overexploitation, etc.) have led to severe fragmentation of
suitable habitats and gradual habitat degradation of suitable habitats
for macaque species, resulting in a progressive decline in population
size (Li et al., 2015;
Zhao et al., 2021).
Although some macaque species
have experienced population growth due to effective conservation
measures, others are still on the verge of extinction, with meager
numbers of individuals in the wild and a lack of systematic and
comprehensive data on their status and distribution. Thus, the
conservation of macaques in China faces a significant challenge
(Li et al., 2020;
Huang et al., 2021). It is necessary to
perform further studies on these species to provide scientific and
practical conservation measures referring to their geographical changes
during the Quaternary.
Species Distribution Models (SDMs) are statistical tools based on
environmental and species distribution data to estimate species
preferences for habitat, which are widely used to explore the
trajectories of geographic changes (Guisan
et al., 2013). Some studies based on a few environmental and ecological
variables were made on M. assamensis(Regmi et al., 2018;
Khanal et al., 2019), M .leonina and M . mulatta(Sun et al., 2020). However, using only
current occurrence data to train SDM may reflect incomplete species
ecological niches that cannot match past climatic environments, likely
offering limited information to dynamically identify the drivers of
their early declines leading to their current reduced population status
(Scheele et al., 2017). Paleontological
fossils provide unique perspectives for exploring the past existence of
species in time and space (Lentini et al.,
2018). Until now, relatively few studies have combined fossil data with
SDM to provide a longer time-scale perspective for geographic changes
and management of threatened animals due to difficulties in data
collection and quantification of long-time-scale ecology
(Nogués-Bravo et al., 2016;
Gibson et al., 2019). Establishing
dynamic spatial-temporal distribution models, referring to the
alterations of climate, vegetation types, geological features,
anthropogenic activities, and evolutionary changes, is demanded to make
a tangible conservation strategy, especially in expecting their shifting
direction and survival prospects. Such a model allows us to identify
appropriate possible geographic changes, which can be referred to
conservation measurements in advance. Macaque (Macaca) in
mainland East Asia, including fossil and extant taxa, and their
distribution profiles from the beginning of the Quaternary (Late
Pleistocene) to the present can provide ideal materials for such an
endeavor. Thus, this study’s aims: 1) with the variables relevant to the
changes in the environment, climate, ecology, geography, and
human-induced activities to establish the models reconstructing
macaques’ past, current, and future distributions patterns of suitable
habitats during the Quaternary; 2) identify the significant factors
driving such changes; and 3) establish a database-driven geographic
model for macaques.