Discussion
The takin is a large montane species with a seasonal migration (Guan et
al.,2013), and preference for habitat with forest cover and low human
disturbance (Guan et al., 2015). The previously published species
distribution map used in the threat classification in the IUCN Red List
includes large areas of distribution in the Sichuan Basin plain,
characterized by relatively low elevation and a high density of human
disturbances, where no suitable takin habitat exists. Our analysis,
based on readily available environmental data and a standard habitat
suitability modeling approach, indicate that the CDR in Sichuan is
substantially larger than its likely realized distribution(Figure 2).
Our informed prediction of the total area of habitat available was only
19% of the area used to determine its threat classification,
potentially vastly underestimating their extinction risk. Therefore, we
suggest two steps to adjust Sichuan takin CDR and improve the accuracy
of the IUCN Red List assessment. First, eliminate patch B and C where
there is no effective habitat for takin. Second, shrink the east range
of area A based on the boundary of these results and the known elevation
lower limits (1,000m).
Our approach in this study was conservative. In reality, takin
populations are sensitive to intense human disturbances (Zeng et al,
2008, Guan et al.,2015) and their populations are strongest within the
nature reserve network and nearby forests that are protected by rangers
from extensive human activities. This is supported by both the species
distribution model results of this study, which indicated that more than
40% suitable habitat was located within PAs, and our previously
published distribution, in which we found 77% of suitable takin habitat
was located within 3km from the border of PAs in northern Minshan (Guan
et al.,2015). It is likely that further species distribution models,
with additional habitat disturbance variables, would indicate that the
real world distribution of takins would be much smaller than current
maps.
The IUCN Red List assessment is the most widely applied standard and
reference for wildlife conservation used to determine priorities for
conservation and ecological studies (Pimm et al., 2014). Thus, the
accuracy of Red List assessments has global impact. The distribution of
takin in our reassessment makes a clear case for the use of basic
occurrence data to reduce inaccuracy, as about 40% of the CDR was
outside of their possible distribution area. By contrast, giant panda
distribution range in the same region is much more elaborate in shape
and closer to their real world distribution (Tang et al., 2020), as the
result of enormous monitoring and focal surveys (Zheng et
al.,2012;Foretry Department of Sichuan Province,2015 ). Such condition
demonstrate that the accuracy of estimats are highly varied among
species, even those that are sympatric.
Species distributions are extremely important topics in both biology and
ecology (Jetz & Guralnick, 2012; Pimm et al., 2014; Schluter& Pennell,
2017), since they evolve through both long-term evolutionary pressures
and interactions with contemporary environmental and anthropogenic
impacts. Thus, they are also a primary concern in wildlife conservation.
For many common species on Red List, the occurrence data for
distribution assessments and population estimates are still lacking
(Roberts et al., 2016; Ocampo-Peñuela et al., 2016; Popov et al.,2017).
To date, there are 17,878 species assessed by IUCN classified as “Data
Deficient”, though comprising only 17.8% of all assessed species (IUCN
2020). As more research is done this percentage decreases, supporting
more reliability in conservation assessments and more effective
planning. We recognize that the data for species assessments often
originate from widespread and long-term surveys, which are dependent on
numerous factors, including the number of individuals participating in
the research, support from pertinent stakeholders, and funding
availability. However, as even the most conservative estimates indicate
that the rate of extinction is 100 times higher than the normal
background rate between the Earth’s six mass extinction events
(Ceballos, et al., 2015). It is imperative that more targeted studies
and surveys are completed to rapidly produce the critical data for
conservation. Our results are likely true for numerous species, and
there are significant opportunities for IUCN Red List species
distribution estimates to be improved by including even basic biological
limits and conservation dependencies (e.g. takin are not found within
cities or other densely populated areas or below 1000m asl) into
distribution maps (Sillero et al.,2014; Syfert et al.,2014; Ramesh et
al.,2017;Gomes et al.,2018).
Biodiversity conservation has often been seen to conflict with economic
development, lead to relatively limited conservation-related investment
from governments, particularly those of developing countries. With the
global economy growth and poverty reductions, long term monitoring and
survey work in large areas become more affordable and feasible (Cordero
et al., 2020); the body of related data is growing. For example, a
recently deployed widespread infrared camera monitoring network in China
has contributed national species distribution data (Li, 2020). However,
the practical use of these data into species assessments and
conservation actions remain to be seen. As data becomes increasingly
available, it is absolutely essential that ecologists, biologist,
conservation scientists and other organizations share data through
transparent collaborations to improve our capacity to assess and protect
wildlife.
Conclusion
By using the takin as a case study, we found significant disparities
between their current published range in the IUCN Red List based on
basic habitat requirements of the species. These differences can have
substantial implications on the conservation of the species, including
its threat classification, prioritization for funding and research,
political and public attention, and more. Our findings related to the
takin are likely exemplary of numerous species, even those not
classified as “Data Deficient.” We strongly encourage an increased
emphasis on widespread assessment of species ranges, even with only the
most basic and intuitive data, to increase their accuracy and efficacy
in conservation planning.
Acknowledgment: This work was funded by National Natural
Science Foundation of China (31300319). We are grateful for the support
from the Forestry Department of Sichuan Province, including data, and
extend our thanks those who conducted field surveys and persistent
monitoring in takin range for years, constructing the very foundation of
our study.