A framework for monitoring the status of populations: An example from
wader populations in the East Asian–Australasian flyway
Tatsuya Amano
a,b,
*
, Tamás Székely
c
, Kazuo Koyama
d
, Hitoha Amano
e,f
, William J. Sutherland
b
a
Biodiversity Division, National Institute for Agro-Environmental Sciences, 3-1-3, Kannondai, Tsukuba-shi, Ibaraki 305-8604, Japan
b
Conservation Science Group, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
c
Biodiversity Lab, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
d
Japan Bird Research Association, Sumiyoshi-cho 1-29-9, Fuchu-shi, Tokyo 183-0034, Japan
e
Lake Biwa Museum, Oroshimo-cho 1091, Kusatsu-shi, Shiga 525-0001, Japan
f
Center for Ecological Research, Kyoto University, Hirano 2-509-3, Otsu-shi, Shiga 520-2113, Japan
article info
Article history:
Received 2 February 2010
Received in revised form 31 May 2010
Accepted 8 June 2010
Available online 2 July 2010
Keywords:
Agricultural intensification
Hierarchical model
Population decline
Population index
Shorebirds
abstract
The loss of biodiversity is an ongoing problem and it is essential that a framework is established for
revealing the status, identifying threats and monitoring future changes of populations. This study focuses
on wader populations in the East Asian–Australasian flyway, and aims to develop a three-step framework
for monitoring the status of populations. First, population changes of waders are quantified by estimating
population indices from nationwide survey data in Japan between 1975 and 2008. Second, species char-
acteristics shared by declining waders are identified using a phylogenetic comparative method. Finally,
based on the revealed characteristics of declining species, composite indices are created for monitoring
changes in wader communities in the East Asian–Australasian flyway. The estimated population indices
revealed that 12 species out of 41, and 16 out of 42 have declined significantly during spring and autumn
migration, respectively, in at least one of the past 10, 20 or 30 year-periods. Phylogenetic comparative
analysis revealed that both the use of rice fields and dependence on the Yellow Sea negatively affected
the population trends of waders. These results are consistent with the hypothesized negative impact
of agricultural intensification caused by land consolidation in Japanese rice fields, and habitat loss and/
or degradation in the Yellow Sea caused by the rapid growth of populations and economies in China
and South Korea. The framework developed in this study can be applied to a wide range of species,
and should play an important role in monitoring population trends and identifying threats to those spe-
cies in future.
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
The loss of biodiversity is an ongoing problem: of the species
whose status was evaluated in 2008, 22% vertebrates, 41% inverte-
brates and 70% plants are listed by the International Union for Con-
servation of Nature (IUCN) as threatened with extinction (IUCN,
2009). To counter this trend, in 2002, 188 nations signed the Con-
vention on Biological Diversity’s 2010 target of ‘‘achieving ...a sig-
nificant reduction of the current rate of biodiversity loss” (UNEP,
2002). A latest study reported that this target will not be achieved
(Butchart et al., 2010) and thus, measuring trends in the state of
biodiversity, and identifying the threats remains an urgent task
for both global and local conservation (Gregory et al., 2005; Amano
et al., in press).
Earlier studies have revealed population declines (Krebs et al.,
1999; Thomas et al., 2004b), identified potential threats to species
(Donald et al., 2001; Cardillo et al., 2005; Long et al., 2007) or pro-
vided methods for monitoring population changes and the effects
of measures to restore populations in future (Gregory et al.,
2005; Loh et al., 2005). However, most studies have achieved these
three processes separately, using different types of approaches, and
without a common framework for measuring and monitoring the
status of populations. Since there is currently a geographical dis-
parity in the availability of information about the status of biodi-
versity (Collen et al., 2009), attempts to evaluate the status of
biodiversity should target global coverage. Therefore, for a success-
ful conservation strategy, it is essential to establish a framework
for determining conservation status, identifying threats and moni-
toring future population changes.
This study aims to develop such a framework, focusing on wad-
ers in the East Asian–Australasian flyway. Waders (or shorebirds)
have become one of the most threatened bird groups. 48% of
migratory wader populations with sufficient data are declining
0006-3207/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.biocon.2010.06.010
* Corresponding author at: Biodiversity Division, National Institute for Agro-
Environmental Sciences, 3-1-3, Kannondai, Tsukuba-shi, Ibaraki 305-8604, Japan.
Tel./fax: +81 29 838 8245.
E-mail address: amatatsu@affrc.go.jp (T. Amano).
Biological Conservation 143 (2010) 2238–2247
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Biological Conservation
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