Carol Cerda-Peña

The area of habitat patches is a significant factor when determining species‐richness in any given habitat. However, this area effect is not the same for every taxonomic group and can change if is considered together with other habitat variables. The main objective of this study was to identify the importance of wetland area for waterbird species‐richness when it is considered in conjunction with other habitat variables. Studies published in the Scopus and Web of Science databases in marine/coastal and inland wetlands were reviewed. A vote‐counting approach was conducted to evaluate how many studies include area as a major variable, and a meta‐analysis was performed to measure the effect size of the relationship between area and species‐richness. Area was a significant predictor of waterbird species‐richness in most of the studies (28 of 40 studies, 70%) as assessed by the vote‐counting approach, and the mean effect size was high (r = 0.81, n = 1 studies) in the meta‐analysis. Few studies reported the shape of the relationship between habitat area and species‐richness, but most reported a positive correlation. Although the species–area relationship is widely recognized, our review shows that an important proportion of studies (30%) also found that other habitat variables were significant variables when they were considered together with habitat area. Consequently, in the case of wetlands, habitat area should be considered in conservation, but not as the only measure of management and restoration if the objective is to conserve waterbird biodiversity by improving species‐richness.

A. araucana is an endemic species of the temperate forests from Chile and Argentina; protected in both countries and categorized as in danger of extinction. Individuals of this species have begun to show foliar damage (i.e., discoloration) in branches and upper parts. The discoloration begins from the base to the top and from the trunk to the branches with necrotic rings appearing; in some cases causing death; and is currently attributed to an as yet unknown disease. This study focuses on the first protective layer of plants against environmental stress and pathogens; known as leaf waxes. The abundance and distribution of three classes of leaf waxes (long chain fatty acids; alkanes and alcohols) were measured in healthy individuals of A. araucana from different sites and individuals that present foliar damage (sick individuals). In the case of sick individuals; their leaf waxes were measured considering the level of leaf damage; that is; leaves without; medium and full foliar damage. The most abundant class of leaf wax in both sick and healthy individuals was fatty acids; followed by alkanes and then alcohols; with common dominant chains; C₂₈ fatty acid; C₂₉ alkane and C₂₄ alcohol. Sick individuals have higher abundances of alkanes and alcohols than healthy individuals. The leaves of sick individuals have lower values of distribution indices (the carbon preference index of fatty acids and average chain length of alkanes) as foliar damage increases that are interpreted as a reduction of in vivo biosynthesis of waxes. This is the first evidence of A. araucana response to a still unknown disease that is killing individuals of this endemic species.