A Multi-scale Approach to Investigating the Wintering Habitat Selection of Red-crowned Cranes in the Yancheng Nature Reserve, China

A B S T R A C T The red-crowned crane (Grus japonensis) is a rare and endangered species that lives in wetland habitats. In this study, we first compared crane habitat selection in December, 2013 and January, 2014 using the Neu method in the Yancheng National Reserve (YNR). We then explored the relative importance of habitats (plot, landscape) and spatial factors on red-crowned crane abundance at multiple scales using regression models and variation partitioning approaches. Our results indicated that seepweed (Suaeda salsa) tidal flats and reed ponds were the favored habitats by cranes in December and January, respectively. The variation partitioning results indicated that plot and landscape factors were the determining factors of crane abundance in December, but plot features were more important in January. Furthermore, the pure and total effects of plot factors, and the combined effects of plot, landscape and spatial factors, increased significantly from December to January. At plot scale, vegetation coverage and road distance were the crucial variables that determine crane abundance in both months. At landscape scale, percentage of reed ponds and percentage of seepweed tidal flats showed a positive independent effect on crane abundance in both months. Percentage of paddy fields was also a significant variable in December, whereas percentage of fishponds was in January. Our study indicated that crane habitat selection and the determining factors changed over time due to food availability and human disturbance (e.g., reed pond and fishpond harvests). Our results encourage the application of partitioning methods in avian ecology because they provide a more in-depth understanding of the importance of different explanatory variables over traditional regression methods. Efforts should be made to strengthen wetland restoration and improve the mitigation of human disturbance in the YNR

Percentages of the total variance in red-crowned crane occurrence data explained by plot, patch, and landscape variables at the second hierarchical level; a, b, c are unique effects of plot, patch and landscape variables, respectively; d, e, f, g are fractions indicating their combined effects.

<p>Percentages of the total variance in red-crowned crane occurrence data explained by plot, patch, and landscape variables at the second hierarchical level; a, b, c are unique effects of plot, patch and landscape variables, respectively; d, e, f, g are fractions indicating their combined effects.</p

The landscape index of red-crowned crane suitable habitat in the YRDNR.

<p>North: northern part of the YRDNR; South: southern part of the YRDNR; Total: the entire reserve; CA: total suitable habitat area; PLAND: proportion of suitable habitat area; AREA_MN: average patch area of suitable habitat; PG: protection gap area in the YRDNR; PPG: percentage of protection gap area with total suitable habitat in the YRDNR.</p><p>The landscape index of red-crowned crane suitable habitat in the YRDNR.</p

Percentages of the total variance in red-crowned crane occurrence data explained by habitat and spatial variables at the first hierarchical level.

<p>(a) The variance explained by habitat variables; (b) the variance explained by spatial variables; and (c) the variance explained by combination of habitat and spatial variables.</p

Habitat suitability map and protection gap for red-crowned cranes used by the final autologistic model.

<p>Red: suitable habitat for the red-crowned crane in the core zone of the YRDNR. Green: suitable habitat for the red-crowned crane outside the core zone of the YRDNR. Blue: Yellow River in the YRDNR. Light gray: experimental zones of the YRDNR. Gray: buffer zones of the YRDNR. Dark gray: core zones of the YRDNR.</p

Location of the Yellow River Delta Nature Reserve in China.

<p>'Absence' and 'presence' indicate the absence and presence sampling points of red-crowned cranes. Blue: Yellow River in the YRDNR. Light gray: experimental zones of the YRDNR. Light green: buffer zones of the YRDNR. Dark green: core zones of the YRDNR.</p

Variable parameters for the final autologistic model with a neighborhood size of 8 km.

<p>**: p-value<0.01;</p><p>***: p-value <0.001</p><p>Variable parameters for the final autologistic model with a neighborhood size of 8 km.</p

Design and implementation of a C++ toolkit for integrated medical image processing and analyzing

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Intermolecular Oxidative Radical Addition to Aromatic Aldehydes: Direct Access to 1,4- and 1,5-Diketones via Silver-Catalyzed Ring-Opening Acylation of Cyclopropanols and Cyclobutanols

A novel silver-catalyzed ring-opening acylation of cyclopropanols and cyclobutanols is described. The reaction proceeds under mild and neutral conditions and provides a facile access to nonsymmetric 1,4- and 1,5-diketones in promising yields with broad substrate scope. Mechanistic studies including DFT calculations suggest the involvement of an uncommon water-assisted 1,2-HAT process, which is strongly exothermic and thus promotes addition of carbon radicals to aldehydes. In contrast to traditional reductive radical addition protocols, this work represents the first example of the intermolecular oxidative radical addition to aldehydes, thus offering a novel strategy for the direct synthesis of acyclic ketones from readily accessible aldehydes