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A Multi-Scale Approach to Investigating the Red-Crowned Crane-Habitat Relationship in the Yellow River Delta Nature Reserve, China: Implications for Conservation.

Cao M, Xu H, Le Z, Zhu M, Cao Y - PLoS ONE (2015)

Bottom Line: Landscape factors had the largest total (45.13%) and independent effects (17.42%) at the second level.The hierarchical partitioning results showed that the percentage of seepweed tidal flats were the main limiting factor at the landscape scale.Our study indicates that landscape and plot factors make a relatively large contribution to crane occupancy and that the focus of conservation effects should be directed toward landscape- and plot-level factors by enhancing the protection of seepweed tidal flats, tamarisk-seepweed tidal flats, reed marshes and other natural wetlands.

View Article: PubMed Central - PubMed

Affiliation: Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing City, Jiangsu Province, China.

ABSTRACT
The red-crowned crane (Grus japonensis (Statius Müller, 1776)) is a rare and endangered species that lives in wetlands. In this study, we used variance partitioning and hierarchical partitioning methods to explore the red-crowned crane-habitat relationship at multiple scales in the Yellow River Delta Nature Reserve (YRDNR). In addition, we used habitat modeling to identify the cranes' habitat distribution pattern and protection gaps in the YRDNR. The variance partitioning results showed that habitat variables accounted for a substantially larger total and pure variation in crane occupancy than the variation accounted for by spatial variables at the first level. Landscape factors had the largest total (45.13%) and independent effects (17.42%) at the second level. The hierarchical partitioning results showed that the percentage of seepweed tidal flats were the main limiting factor at the landscape scale. Vegetation coverage contributed the greatest independent explanatory power at the plot scale, and patch area was the predominant factor at the patch scale. Our habitat modeling results showed that crane suitable habitat covered more than 26% of the reserve area and that there remained a large protection gap with an area of 20,455 ha, which accounted for 69.51% of the total suitable habitat of cranes. Our study indicates that landscape and plot factors make a relatively large contribution to crane occupancy and that the focus of conservation effects should be directed toward landscape- and plot-level factors by enhancing the protection of seepweed tidal flats, tamarisk-seepweed tidal flats, reed marshes and other natural wetlands. We propose that efforts should be made to strengthen wetland restoration, adjust functional zoning maps, and improve the management of human disturbance in the YRDNR.

No MeSH data available.


Related in: MedlinePlus

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.
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pone.0129833.g003: 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.

Mentions: Variance partitioning is a quantitative statistical method by which the variation in dependent variables can be decomposed into independent components reflecting the relative importance of different groups of explanatory variables and their joint effects [7, 9]. In this study, variance partitioning was used to decompose the explained variance of the red-crowned crane occurrence data into independent and joint components at two hierarchical levels. The first level of the decomposition was conducted between spatial variables and habitat variables (plot, patch and landscape data sets combined) (Fig 2). At the second level of decomposition, the habitat variables were partitioned into three groups of explanatory variables at the plot, patch and landscape scales. In this analysis, spatial variables were considered as covariables to remove their effects. A series of (partial) binomial logistic regression models were used to calculate the variance decomposition values at the first and second levels using R 2.15 software [32]. This procedure resulted in three fractions at the first level: pure spatial effects, the joint effects of spatial and habitat variables, and pure habitat effects. The second level was decomposed into seven fractions: (a) pure plot-level effects, (b) pure patch-level effects, (c) pure landscape-level effects, combined variation due to the joint effects of (d)plot and patch variables, (e) plot and landscape variables, (f) patch and landscape variables, and (g) plot, patch and landscape variables [11] (Fig 3).


A Multi-Scale Approach to Investigating the Red-Crowned Crane-Habitat Relationship in the Yellow River Delta Nature Reserve, China: Implications for Conservation.

Cao M, Xu H, Le Z, Zhu M, Cao Y - PLoS ONE (2015)

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.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4465972&req=5

pone.0129833.g003: 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.
Mentions: Variance partitioning is a quantitative statistical method by which the variation in dependent variables can be decomposed into independent components reflecting the relative importance of different groups of explanatory variables and their joint effects [7, 9]. In this study, variance partitioning was used to decompose the explained variance of the red-crowned crane occurrence data into independent and joint components at two hierarchical levels. The first level of the decomposition was conducted between spatial variables and habitat variables (plot, patch and landscape data sets combined) (Fig 2). At the second level of decomposition, the habitat variables were partitioned into three groups of explanatory variables at the plot, patch and landscape scales. In this analysis, spatial variables were considered as covariables to remove their effects. A series of (partial) binomial logistic regression models were used to calculate the variance decomposition values at the first and second levels using R 2.15 software [32]. This procedure resulted in three fractions at the first level: pure spatial effects, the joint effects of spatial and habitat variables, and pure habitat effects. The second level was decomposed into seven fractions: (a) pure plot-level effects, (b) pure patch-level effects, (c) pure landscape-level effects, combined variation due to the joint effects of (d)plot and patch variables, (e) plot and landscape variables, (f) patch and landscape variables, and (g) plot, patch and landscape variables [11] (Fig 3).

Bottom Line: Landscape factors had the largest total (45.13%) and independent effects (17.42%) at the second level.The hierarchical partitioning results showed that the percentage of seepweed tidal flats were the main limiting factor at the landscape scale.Our study indicates that landscape and plot factors make a relatively large contribution to crane occupancy and that the focus of conservation effects should be directed toward landscape- and plot-level factors by enhancing the protection of seepweed tidal flats, tamarisk-seepweed tidal flats, reed marshes and other natural wetlands.

View Article: PubMed Central - PubMed

Affiliation: Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing City, Jiangsu Province, China.

ABSTRACT
The red-crowned crane (Grus japonensis (Statius Müller, 1776)) is a rare and endangered species that lives in wetlands. In this study, we used variance partitioning and hierarchical partitioning methods to explore the red-crowned crane-habitat relationship at multiple scales in the Yellow River Delta Nature Reserve (YRDNR). In addition, we used habitat modeling to identify the cranes' habitat distribution pattern and protection gaps in the YRDNR. The variance partitioning results showed that habitat variables accounted for a substantially larger total and pure variation in crane occupancy than the variation accounted for by spatial variables at the first level. Landscape factors had the largest total (45.13%) and independent effects (17.42%) at the second level. The hierarchical partitioning results showed that the percentage of seepweed tidal flats were the main limiting factor at the landscape scale. Vegetation coverage contributed the greatest independent explanatory power at the plot scale, and patch area was the predominant factor at the patch scale. Our habitat modeling results showed that crane suitable habitat covered more than 26% of the reserve area and that there remained a large protection gap with an area of 20,455 ha, which accounted for 69.51% of the total suitable habitat of cranes. Our study indicates that landscape and plot factors make a relatively large contribution to crane occupancy and that the focus of conservation effects should be directed toward landscape- and plot-level factors by enhancing the protection of seepweed tidal flats, tamarisk-seepweed tidal flats, reed marshes and other natural wetlands. We propose that efforts should be made to strengthen wetland restoration, adjust functional zoning maps, and improve the management of human disturbance in the YRDNR.

No MeSH data available.


Related in: MedlinePlus