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Using species combinations in indicator value analyses / Miquel De Cáceres in Methods in ecology and evolution, 3 (2012) 

Public Citation [article]  inMethods in ecology and evolution > 3 (2012) . - 973-982 Titre : Using species combinations in indicator value analyses Type de document : Électronique Auteurs : Miquel De Cáceres ; Pierre Legendre (1946-) ; Susan K. Wiser ; Lluis Brotona Année de publication : 2012 Article en page(s) : 973-982 Langues : Anglais (eng) Résumé : Indicator species are often determined using an analysis of the relationship between the species occurrence or abundance values from a set of sites and the classification of the same sites into site groups (habitat types, community types, disturbance states, etc.). It may happen, however, that a particular site group has no indicator species even if its sites have a community composition that is clearly distinct from the sites of other site groups. This motivates an exploration of the indicator value of not only individual species but also species combinations.Here, we present a novel statistical approach to determine indicators of site groups using species data. Unlike traditional indicator value analysis, we allow indicators to be species combinations in addition to single species. We require that all the species forming the combination must occur in the site to use the combination as an indicator. We present a simple algorithm that identifies the set of indicators (each one being either a single species or a species combination) that show high positive predictive value for the target site group. Moreover, we demonstrate the use of the percentage of sites of the site group where at least one of its valid indicators occurs to determine whether the group can be reliably predicted throughout its range.Using a simulation study, we show that if two species are not strongly correlated and their frequency in the data set is larger than the frequency of sites belonging to the site group, the joint occurrence of the two species has higher positive predictive value for the site group than the two species taken independently.We illustrate the proposed method by determining which combinations of vascular plants can be used as indicators for 29 shrubland and forest vegetation types of New Zealand.The proposed methodology extends traditional indicator value analyses and will be useful to develop multispecies ecological or environmental indicators. Further, it will allow newly surveyed sites to be reliably assigned to previously defined vegetation types. Lien pérenne : DOI : 10.1111/j.2041-210X.2012.00246.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=142970 De Cáceres, Miquel, Legendre, Pierre (1946-), Wiser, Susan K., Brotona, Lluis 2012 Using species combinations in indicator value analyses. Methods in ecology and evolution, 3: 973-982.

Documents numériques

Consultable Article (2012) URL

Assessing biodiversity in forests using very high-resolution images and unmanned aerial vehicles / Stephan Getzin in Methods in ecology and evolution, 3 (2012) 

Public Citation [article]  inMethods in ecology and evolution > 3 (2012) . - 397-404 Titre : Assessing biodiversity in forests using very high-resolution images and unmanned aerial vehicles Type de document : Imprimé Auteurs : Stephan Getzin ; Kerstin Wiegand ; Ingo Schöning Année de publication : 2012 Article en page(s) : 397-404 Catégories : [CBNPMP-Thématique] Télédétection Résumé : Structural diversity and niche differences within habitats are important for stabilizing species coexistence. However, land-use change leading to environmental homogenization is a major cause for the dramatic decline of biodiversity under global change. The difficulty in assessing large-scale biodiversity losses urgently requires new technological advances to evaluate land-use impact on diversity timely and efficiently across space. While cost-effective aerial images have been suggested for potential biodiversity assessments in forests, correlation of canopy object variables such as gaps with plant or animal diversity has so far not been demonstrated using these images. Here, we show that aerial images of canopy gaps can be used to assess floristic biodiversity of the forest understorey. This approach is made possible because we employed cutting-edge unmanned aerial vehicles and very high-resolution images (7 cm pixel−1) of the canopy properties. We demonstrate that detailed, spatially implicit information on gap shape metrics is sufficient to reveal strong dependency between disturbance patterns and plant diversity (R2 up to 0·74). This is feasible because opposing disturbance patterns such as aggregated and dispersed tree retention directly correspond to different functional and dispersal traits of species and ultimately to different species diversities. Our findings can be used as a coarse-filter approach to conservation in forests wherever light strongly limits regeneration and biodiversity. Lien pérenne : DOI : 10.1111/j.2041-210X.2011.00158.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=151520 Getzin, Stephan, Wiegand, Kerstin, Schöning, Ingo 2012 Assessing biodiversity in forests using very high-resolution images and unmanned aerial vehicles. Methods in ecology and evolution, 3: 397-404.

Documents numériques

Consultable Article (2012) URL