Multivariate analysis and self-organizing mapping applied to analysis of nest-site selection in Black-tailed Gulls

Lee, Who-Seung; Kwon, Young-Soo; Yoo, Jeong‐Chil; Song, Mi‐Young; Chon, Tae‐Soo

doi:10.1016/j.ecolmodel.2005.08.043

Cited by 21 publications

(12 citation statements)

References 33 publications

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“…MDS, PCA and CCA), these results were not presented because they were much less interpretable than those of the ANN; a result similar to that of Olden & Jackson (2002). In addition, comparisons between SOM and traditional multivariate statistics can be found in other papers (Brosse, Giraudel & Lek, 2001; Giraudel & Lek, 2001; Lee et al. , 2006).…”

Section: Discussionsupporting

confidence: 90%

Fish assemblage patterns in the littoral zone of a European reservoir

2007

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1. Although reservoirs are common aquatic habitats in Europe, there is little quantitative information on the spatial organisation of fish assemblages inhabiting their littoral zones. Consequently, we characterised fish assemblage structure in the littoral zone of a reservoir (Lake Pareloup) in SW France during late spring, summer and early autumn (the growing season). 2. We measured the relative abundance of fish, weekly from mid-May to mid-October, using point abundance sampling by electrofishing. We identified temporal patterns in assemblage structure using hierarchical cluster analysis, and then characterised the spatial distribution of 17 defined ecospecies using a Kohonen self-organising map (SOM, an unsupervised Artificial Neural Network). 3. Our analyses revealed three distinct faunal structures within the littoral zone. From midMay to mid-July, adults and young-of-the-year (0+) occupied separate habitats, with most 0+ fish in vegetated habitats and adults in open water. From mid-July to late August, some 0+ co-occurred with adults, but most 0+ fishes remained in vegetated areas. Finally, from late August to mid-October, most fish (both 0+ and adults) left the vegetation for unvegetated littoral habitats, the exception being fish species known to be dependent on macrophytes. 4. Contrary to patterns for adult fishes, the 0+ fish assemblage was dynamic. These dynamics were driven by ontogenetic species-specific habitat changes. Consequently, there was little evidence of stable assemblages or strong assemblage-habitat relationships that would be expected of an 'interactive' assemblage. It is likely that the patterns observed are a result of species-specific response to habitat availability in the lake.

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Section: Discussionsupporting

confidence: 90%

Fish assemblage patterns in the littoral zone of a European reservoir

2007

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“…Although we originally analysed our data using traditional multivariate methods (e.g. CCA, PCA, MDS) the results are not presented because they were less interpretable than those of the SOM; a conclusion similar to that of previous papers comparing SOM and traditional multivariate statistics (Blayo and Demartines 1991;Brosse et al 2001;Giraudel and Lek 2001;Lee et al 2006, Zhang et al 2008.…”

Section: Discussionmentioning

confidence: 71%

Rapid evaluation of threats to biodiversity: human footprint score and large vertebrate species responses in French Guiana

Thoisy¹,

Richard‐Hansen

Goguillon³

et al. 2010

Biodivers Conserv

102

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Although there is an extensive literature demonstrating the impact of human activities on both species extinction risk and local ecological processes, the methodological tools that allow for the visualization and quantification of the intensity of the observed and forthcoming impacts are lacking. Here we propose a Footprint index for French Guiana, (northern Atlantic coast of South America) which sums up the expected and proven disturbances on biodiversity. The index was developed by superimposing geographical and human data, including human population densities, land use, settlements and camps, mining and forest activities, tracks, roads and rivers. The relevance of the index as a general measure of anthropic impact on large terrestrial fauna was estimated by investigating the structure of the large terrestrial vertebrate assemblages, including primates, large frugivorous birds, rodents and ungulates, in relation to the extent of disturbances. The abundance of large terrestrial fauna was assessed using the line-transect sampling method in 34 forest sites facing different disturbance levels, including hunting, logging and B. de Thoisy (&) Association Kwata ''Study and Conservation of French Guianan Wildlife'', BP 672, fragmentation, and consequently different footprint scores. A Self Organizing Map was used to combine species abundances and disturbance scores. It allowed us to rank species in accordance to their sensitivity towards disturbances, identifying the response of fauna to different concomitant threats. The index provided correct identification of sites with similar threats which proves it is a relevant estimator of human disturbance. In addition, the richness of animal communities and abundances of several seed dispersers and predators were negatively correlated to the index (e.g. large monkeys and frugivorous birds, r 2 = 0.49, P \ 0.0001 and r 2 = 0.48, P \ 0.0001, respectively), indicating its reliability in identifying areas where animal communities are disturbed. The index could, therefore, constitute a useful tool to identify areas where ecological processes supported by those species are expected to be disrupted, and where they are already disrupted. Furthermore, the footprint index can deal with lack of field data or with only partially valid information, and so may directly help land managers forecast and, hopefully, mitigate forthcoming impacts resulting from the development of human activities.

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“…The area of the island is 98,380 m 2 , the highest point is about 115 m above sea level, and cliffs with a slope of over 45°surround the coastline. The sedge Carex boottiana, which is used as the most common nesting material to build the nest cup, covers the whole island except the rocky cliffs (Lee et al 2006a). During the study, there was only one breeding species, Black-tailed Gulls, on the island, plus one pair of Peregrine Falcons (Falco peregrinus).…”

Section: Study Species and Areamentioning

confidence: 99%

“…We directly measured vegetation cover (50.3 ± 3.1%) and nest-wall (60.2 ± 2.3%) at the time of clutch completion (22.3 ± 0.4 days; 1 = 1 April) ( Table 1). The detailed descriptions on the characteristics data were reported in Lee et al (2006a).…”

Section: Nest Site Characteristicsmentioning

confidence: 99%

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Egg survival is related to the colour matching of eggs to nest background in Black-tailed Gulls

2010

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A long-standing hypothesis posits that, for species with exposed nests, a close match between the colour of the eggs and that of the nest in which they are laid should enhance egg survival, but this has rarely been tested in a rigorous manner. Here, we demonstrate the effects of egg-nest colour matching on egg survival in Black-tailed Gulls (Larus crassirostris) on Hongdo Island, Korea. We quantified the ground colour of eggshells and that of the nest background using a digital camera and computerized RGB and greyscale colour systems. We show that a close match of eggshell ground colour and nest background colour was associated with increased chances of eggs surviving through to hatching. In particular, there were strong survival advantages for eggs matching the nest colour in sites with poor concealment, whereas there was no effect of eggshell ground colour in nests that were more concealed by vegetation. Our findings support the hypothesis that egg colour functions to make eggs cryptic and that egg colouration may be a significant factor affecting egg loss.

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Multivariate analysis and self-organizing mapping applied to analysis of nest-site selection in Black-tailed Gulls

Cited by 21 publications

References 33 publications

Fish assemblage patterns in the littoral zone of a European reservoir

Fish assemblage patterns in the littoral zone of a European reservoir

Rapid evaluation of threats to biodiversity: human footprint score and large vertebrate species responses in French Guiana

Egg survival is related to the colour matching of eggs to nest background in Black-tailed Gulls

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