DOI: 10.5061/dryad.zgmsbccdm
title: Diet composition based on stable isotopic analysis of fecal samples revealed the preference of Black-faced Spoonbill (Platalea minor) for natural wetlands and fishponds

description: Background: Black-faced spoonbill (BFS) is a global endangered species,
 distributed only in the coastal zones of East Asia. Xinghua Bay is one of
 the main wintering sites and migration stopovers of BFS in mainland China.
 However, with the reduction and degradation of natural wetlands, it is
 uncertain whether the constructed wetland can provide habitat for the
 endangered BFS. Research on diet of BFS will help to understand their
 preference between natural and artificial wetlands, and also provide
 reference for their conservation and habitat restoration. Results: In the
 early winter, the proportion of Palaemonidae in BFS’s food was as high as
 74.4%, while that of other food was only 3.0% to 6.0%. In the late winter,
 the food contribution of BFS was as follow: Portunidae 39.3% &gt;
 Palaemonidae 26.1% &gt; Cyprinidae 8.8% &gt; Mugilidae 8.5%
 &gt; Gobiidae 7.3% &gt; Crucian 5.1% &gt; Whiteshrimp 4.8%.
 The proportion of Portunidae exceeded that of Palaemonidae, and together
 with Palaemonidae, it has become the main food of BFS in late winter.
 Conclusion: The diet composition of BFS between the early and late winter
 was significantly different, which may be due to seasonal changes in food
 resources. Natural wetlands are the main feeding grounds of BFS, but
 artificial wetlands also provide them with supplementary feeding grounds
 and resting places. Aquaculture ponds play an important ecological
 function in maintaining the overwintering population of BFS in Xinghua
 Bay.
description: From December 2017 to February
 2020, 45 potential food samples and 199 fecal samples of BFS were
 collected during six sampling period, of which Cyprinidae, Mugilidae,
 Portunidae, Gobiidae and Palaemonidae were collected from natural wetlands
 and Crucian (Carassius auratus) and Whiteshrimp (Litopenaeus Vannamei)
 were collected from artificial wetland. Their stable isotope values (δ13C,
 δ15N) were measured to obtain the food composition information of
 BFS. The mean and standard deviation of stable
 isotope values of samples were calculated, and the outliers that deviated
 from the mean by more than twice the standard deviation were screened out.
 The 14 potential food sources were divided into 7 groups, of which
 Cyprinidae, Mugilidae, Portunidae, Gobiidae and Palaemonidae were
 collected from natural wetlands and Crucian and Whiteshrimp were collected
 from artificial wetland. The
 differences of δ13C and δ15N values between fecal samples and potential
 food samples were compared by One-Way ANOVA analysis. All isotope data
 were expressed as Mean± standard deviation (Mean ± SE), and p &lt;
 0.05 was considered as significant difference. 
 The
 most commonly used model to study food composition by stable isotopic
 analysis is Bayesian mixing model. It can take into account the variable
 nondeterministic factors with relatively high accuracy and a wide range of
 application. We used the R package simmr, which can be used to process the
 mixing equations of stable isotope data within the framework of the
 bayesian mixing model (Parnell, Inger, Bearhop, & Jackson, 2010;
 Parnell et al., 2013). Fecal values were calibrated by the discrimination
 factors (δ13C=1.15‰, δ15N=2.91‰), which were estimated for fecal samples
 of birds in general (Caut, Angulo, & Courchamp,
 2009).
description: Fecal values were calibrated
 by the discrimination factors (δ13C=1.15‰, δ15N=2.91‰), which were
 estimated for fecal samples of birds in general (Caut, Angulo, &
 Courchamp, 2009.
 doi:10.1111/j.1365-2664.2009.01620.x).