Global patterns of evolutionary distinct and globally endangered amphibians and mammals.

BACKGROUND: Conservation of phylogenetic diversity allows maximising evolutionary information preserved within fauna and flora. The "EDGE of Existence" programme is the first institutional conservation initiative that prioritises species based on phylogenetic information. Species are ranked in two ways: one according to their evolutionary distinctiveness (ED) and second, by including IUCN extinction status, their evolutionary distinctiveness and global endangerment (EDGE). Here, we describe the global patterns in the spatial distribution of priority ED and EDGE species, in order to identify conservation areas for mammalian and amphibian communities. In addition, we investigate whether environmental conditions can predict the observed spatial pattern in ED and EDGE globally. METHODS AND PRINCIPAL FINDINGS: Priority zones with high concentrations of ED and EDGE scores were defined using two different methods. The overlap between mammal and amphibian zones was very small, reflecting the different phylo-biogeographic histories. Mammal ED zones were predominantly found on the African continent and the neotropical forests, whereas in amphibians, ED zones were concentrated in North America. Mammal EDGE zones were mainly in South-East Asia, southern Africa and Madagascar; for amphibians they were in central and south America. The spatial pattern of ED and EDGE was poorly described by a suite of environmental variables. CONCLUSIONS: Mapping the spatial distribution of ED and EDGE provides an important step towards identifying priority areas for the conservation of mammalian and amphibian phylogenetic diversity in the EDGE of existence programme.

Understanding global patterns of mammalian functional and phylogenetic diversity.

Documenting and exploring the patterns of diversity of life on Earth has always been a central theme in biology. Species richness despite being the most commonly used measure of diversity in macroecological studies suffers from not considering the evolutionary and ecological differences among species. Phylogenetic diversity (PD) and functional diversity (FD) have been proposed as alternative measures to overcome this limitation. Although species richness, PD and FD are closely related, their relationships have never been investigated on a global scale. Comparing PD and FD with species richness corroborated the general assumptions of surrogacy of the different diversity measures. However, the analysis of the residual variance suggested that the mismatches between the diversity measures are influenced by environmental conditions. PD increased relative to species richness with increasing mean annual temperature, whereas FD decreased with decreasing seasonality relative to PD. We also show that the tropical areas are characterized by a FD deficit, a phenomenon, that suggests that in tropical areas more species can be packed into the ecological space. We discuss potential mechanisms that could have resulted in the gradient of spatial mismatch observed in the different biodiversity measures and draw parallels to local scale studies. We conclude that the use of multiple diversity measures on a global scale can help to elucidate the relative importance of historical and ecological processes shaping the present gradients in mammalian diversity.

Effect of marine bacterial isolates on the growth and morphology of axenic plantlets of the green alga Ulva linza.

The green marine macroalga, Ulva linza, adopts an "atypical" form when grown in the absence of bacteria. Twenty unique strains of periphytic bacteria, isolated from three species of Ulva, were identified by 16S rDNA sequencing. These isolates were assessed for their effect on the growth and morphological development of axenic plantlets of U. linza. Results showed that the effect of bacterial strains was strain- but not taxon-specific. Thirteen isolates returned the aberrant morphology to normal and of these, five also significantly increased growth rate. One isolate increased growth, but had no effect on morphology. Biofilms of some of these isolates stimulated the settlement of Ulva zoospores but there was no correlation between bacterial isolates that stimulated zoospore settlement and those that initiated changes in morphology and/or growth of the cultured alga.

Perception of temporal order and the identification of components in taste mixtures.

The capacity of humans to identify the components of taste mixtures is limited to 3 for most people [D.G. Laing, C. Link, A. Jinks, I. Hutchinson, The limited capacity of humans to identify the components of taste mixtures and taste-odor mixtures. Perception 31 (2002) 617-635]. Here, the hypothesis that temporal processing differences have a major role in limiting capacity is investigated. Thirty two subjects were trained to identify sucrose, sodium chloride and citric acid at FIVE concentration levels and were then required to indicate (1) which tastant was perceived first and (2) the identity of each component, in binary and ternary mixtures. Within each mixture set, e.g. sucrose-citric acid, the concentrations of components were adjusted to provide some conditions where intensities and time differences in processing the individual components were minimized. With binary mixtures, changes in intensity resulted in identification of only one component when the differences were largest, and both being identified when intensities were similar. In contrast, subjects found it difficult to indicate which component was perceived first when the intensities were similar and easy when they were substantially different. The most profound effects occurred with ternary mixtures. With each of the three sets, there were several where subjects could not indicate which component was perceived first, and in 13/18 mixtures not all components were identified above chance. Indeed, the most common number of components identified was 2. However, although perception of order was lost in a number of mixtures, this did not preclude identification of one or all three components. This result contrasts with the finding with odors where total loss of order resulted in loss of identity of all components in ternary mixtures [A. Jinks, D.G. Laing, Temporal processing reveals a mechanism for limiting the capacity of humans to analyze mixtures. Cognitive Brain Res. 8 (1999) 311-325]. Thus, loss of identity with taste mixtures seems to occur to a lesser degree. Indeed suppression rather than temporal effects may be the main cause of the loss of identity of components with ternary taste mixtures.