Response curves of environmental variables with highest contribution to occurrence of Scaly-sided Merganser.

<p>Solid line is the mean response curve and dotted lines are ±1 SD.</p

The study area in Yuan River and its location within the Yangtze River Basin in China.

<p>The study area in Yuan River and its location within the Yangtze River Basin in China.</p

Kruskal-Wallis test of the effects of development stage and habitat type on Siberian crane activity time.

***<p>p<0.001;</p>**<p>p<0.01;</p>*<p>p<0.05; and</p>n.s<p> = not significant (p>0.05);</p

Map of Poyang lake (light blue colored area) and its five major tributaries.

<p>Map of Poyang lake (light blue colored area) and its five major tributaries.</p

Plants of vegetation survey.

<p>A: <i>Vallisneria spiralis</i> and B: <i>Potentilla limprichtii</i>.</p

Map of Poyang Lake National Natural Reserve in winter season.

<p>The blue colored area shows shallow water habitat, light blue belt around the shallow water area is mudflats and red area is wet meadow.</p

Using Species Distribution Model to Estimate the Wintering Population Size of the Endangered Scaly-Sided Merganser in China

<div><p>Scaly-sided Merganser is a globally endangered species restricted to eastern Asia. Estimating its population is difficult and considerable gap exists between populations at its breeding grounds and wintering sites. In this study, we built a species distribution model (SDM) using Maxent with presence-only data to predict the potential wintering habitat for Scaly-sided Merganser in China. Area under the receiver operating characteristic curve (AUC) method suggests high predictive power of the model (training and testing AUC were 0.97 and 0.96 respectively). The most significant environmental variables included annual mean temperature, mean temperature of coldest quarter, minimum temperature of coldest month and precipitation of driest quarter. Suitable conditions for Scaly-sided Merganser are predicted in the middle and lower reaches of the Yangtze River, especially in Jiangxi, Hunan and Hubei Provinces. The predicted suitable habitat embraces 6,984 km of river. Based on survey results from three consecutive winters (2010–2012) and previous studies, we estimated that the entire wintering population of Scaly-sided Merganser in China to be 3,561 ± 478 individuals, which is consistent with estimate in its breeding ground.</p></div

Nonparametric MANOVA of development stage and habitat type on Siberian crane activity time.

***<p>p<0.001;</p>**<p>p<0.01;</p>*<p>p<0.05; and</p>n.s<p> = not significant (p>0.05).</p><p>Stage refers to development stage (juvenile or adult). The coefficients are the standardized canonical correlation coefficient for individual activities.</p

The density of <i>vallisineria spiralis</i> tuber (ind/m²) in different year.

A<p>: The highest water level in summer at XZHS;</p>B<p>: Days of water level ≥17 m in previous growing season.</p

Summary of GLMs (predictor variables restricted to three or less) supported by survey data.

<p>* See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0127387#pone.0127387.t001" target="_blank">Table 1</a> for definition of terms</p><p>^# interaction term</p><p>^ Maximum likelihood pseudo <i>R</i>^<i>2</i></p><p>Summary of GLMs (predictor variables restricted to three or less) supported by survey data.</p