Abstract:
Climate
changes has been shown to be related to the changes in the distributions
of migratory species, which irreparably harms biodiversity.
In
this study, we evaluated the habitat change and population centroid
shift for 7 orders and 23 different species on the IUCN (International
Union for the Conservation of Nature and Natural Resources) Red List of
migratory birds from 2014-2017 in current to mid-21st (2041-2700)
century by Maximum Entropy method (MaxEnt)
model.
We
found striking spatial variation in the suitability in geography, with
Yangtze River basin losing 9.74% of suitable habitat and Pearl River
basin losing 13% of
habitat.
The
area of suitable habitat decreases over 3% of total habitat area in
China under the RCP2.6, and decreases about 10% of total habitat area
in China under RCP8.5 scenario, with the population centroid of habitat
moving about 50 km to northeast on average. Furthermore, the suitability
of migratory birds will decrease over 3% in future, which will be
difficult for migratory birds to survive. The direction and distance of
population centroid are different for every species. Most of the
individual species in the study will move over 50 km and all the species
will move towards to places with higher suitability. For the whole of
China, the constraint for migratory birds is \(t_{\min}\).
The
dominant variable in southeast China is NDVI, and the northern China is
altitude
(alt).
The
decline in suitable habitat area and shift in population centroid will
lead to the changes in the time and distance of migration process,
resulting in more adverse conditions for the survival of migratory
birds.
Our
study proves the adverse role of climate change in species distribution
which is a prerequisite for protecting species in future.
Introduction
The
number of migratory birds has declined dramatically worldwide since 1970
(Ims et al., 2019; Spooner et al., 2018).
Key
driver of the abundance decline is that climate change exacerbates the
survival pressure of migratory birds (Jacome et al., 2019; Jetz et al.,
2007; Lehikoinen et al., 2019; Mammola et al., 2018; Pearson et al.,
2013; Russell et al., 2015; Saino et al., 2011; Spooner et al., 2018;
Wilson et al., 2019; Yalcin & Leroux, 2018; Yu et al., 2019),which
will
result in the ecological imbalance and the absence of ecological
function (Cohen et al., 2018; Hewson et al., 2016; Keogan et al.,
2018).
It
is critical to understand
how
species spatial distribution changes under the changing climate for
protecting biodiversity and formulating the effective policies (Northrup
et al., 2019; Vickery et al., 2014).
In
past decades, bird populations have declined and habitat has changed a
lot.
Roberts
et al.(2019)
assessed
the change of avian spatial regimes and population in 46 years but did
not explain the reason (Roberts et al., 2019). Previous studies have
made great progress in studying the correlation between habitat
distribution and climate change. Brawn et
al.(2017)illustrated
that
the
population of tropical birds was closely
correlated
to the climate in rainfall (Brawn et al., 2017). Climate change damages
the region’s suitable environmental conditions for certain species
(Sanchez-Bayo & Wyckhuys, 2019; Title & Bemmels,
2018),which
leads to change in their geographic range (Keogan et al., 2018; Saino et
al.,
2011).
Climate
change makes that the growth cycle of migratory birds
hardly keep the match between the
feeding time and the period of rich food resources (Bowler et al., 2019;
Fecchio et al., 2019; Jetz et al., 2007; Kentie et al., 2018; Wilson et
al., 2019).
Bowler
et al.(2019)
corroborated
the general trend that European insectivorous birds communities
was
confirmed to be the same as insect (Bowler et al., 2019).
Saino
et al.(2011) confirmed the reason
of the population decline of European migratory birds was that their
migration phenology mismatches the climate (Saino et al.,
2011).
Despite these lines of evidence, little research has been done to
identify the effects of individual climate variables on species
distribution. Better identification of major climate variables can help
to establish effective policies, which is one of the urgent needs for
biodiversity conservation (Beringer et al., 2011; Both et al., 2010;
Cohen et al., 2018; Dugger et al., 2016; Hoffmann & Sgro, 2011).
Theoretical
research on the correlation between species distribution and climate
change is meaningful to protect biodiversity. To understand the effect
of climate change on the potential distribution pattern of species,
research model has become an important means. Saupe et
al.(2019)
demonstrated
the
MaxEnt model performed well for evaluating the changes in the
distribution of birds at the geographical level (Saupe et al., 2019).
The presence data is widely used in the species distribution model
combing with climate data and proved to be feasible (Finch et al., 2017;
Jacome et al., 2019; Roberts et al., 2019; Saupe et al., 2019).
In
this study, we combined bird sample data and China national scale
climate data to build the species distribution models(SDMs) for 7orders
of migratory birds and 23species in different level on the IUCN red list
(Moran & Kanemoto, 2017). In the study , we explored the current
distribution and the drivers by MaxEnt, and discussed where and how the
distribution may change in the 2050s. Firstly, we used the model to
simulate the current distribution of migratory birds and predicted their
distribution under the future scenarios. Secondly, based on the
simulation of birds’ distribution, we quantified the movement trend by
calculating the species population centroid and identified the
individual contribution of environmental variables. Lastly, we compared
the differences between the distribution and the protected areas to
discuss the effective methods for reducing the biodiversity loss.
Material and methods
Species data
Migratory
birds transport the energy and nutrients within and between the
ecosystems, which is the largest population movement in the world,
connecting the world into a huge ecosystem (Bauer & Hoye, 2014; Russell
et al., 2015). The population of
migratory birds passing through the major flyways dropped by half over
the past 30 years (Runge et al., 2015) and migratory birds got into an
unfavorable position in
Asia
(Kirby et al., 2008).
China is the largest country in Asia lying in
East
Asian-Australasian flyways with high biodiversity (Ma et al., 2019).We
compiled migratory bird data from
2014–2017
Bird
Report(http://www.birdreport.cn/).
The
Bird Report is the most complete and effective summary by bird watchers
in China, accounting for 80% of all bird species,
and
each birdwatching record is sorted up and reviewed by experts to ensure
accuracy. The latitude and longitude of the location were determined by
comparing the geographical locations in Google Earth. We recorded the
bird presence data in ArcGIS10.2, and selected 7 orders of migratory
birds, including 115 species, covering 12156 geographical records. 23
species are endangered species on the IUCN red list(Fig1) (Garnett et
al., 2003; Young et al., 2014). After deleting the duplicate invalid
data, we modelled the potential distribution of both 7 orders of
migratory birds and 23 different IUCN categories species, including 3
critically endangered (CR) species, 5 endangered (EN) species, 9
vulnerable(VU) species and 6 near threatened(NR) species(Table S1). The
locations of migratory birds is showed in Fig.1.