Quantifying components of risk for European woody species under climate change

Estimates of species extinction risk under climate change are generally based on differences in present and future climatically suitable areas. However, the locations of potentially suitable future environments (affecting establishment success), and the degree of climatic suitability in already occupied and new locations (affecting population viability) may be equally important determinants of risk. A species considered to be at low risk because its future distribution is predicted to be large, may actually be at high risk if these areas are out of reach, given the species' dispersal and migration rates or if all future suitable locations are only marginally suitable and the species is unlikely to build viable populations in competition with other species. Using bioclimatic models of 17 representative European woody species, we expand on current ways of risk assessment and suggest additional measures based on (a) the distance between presently occupied areas and areas predicted to be climatically suitable in the future and (b) the degree of change in climatic suitability in presently occupied and unoccupied locations. Species of boreal and temperate deciduous forests are predicted to face higher risk from loss of climatically suitable area than species from warmer and drier parts of Europe by 2095 using both the moderate B1 and the severe A1FI emission scenario. However, the average distance from currently occupied locations to areas predicted suitable in the future is generally shorter for boreal species than for southern species. Areas currently occupied will become more suitable for boreal and temperate species than for Mediterranean species whereas new suitable areas outside a species' current range are expected to show greater increases in suitability for Mediterranean species than for boreal and temperate species. Such additional risk measures can be easily derived and should give a more comprehensive picture of the risk species are likely to face under climate change.     

Characterization of Rhodanese from Cassava Leaves and Tubers

Rhodanese activity has been established in the leaves, in thepeel, and in the flesh of the tuberous part of Manihot esculentaCrantz. The pattern of distribution of enzyme activity is shownto follow that of the concentration of the cyanogenic glucosideestimated on the basis of HCN released. For the first time,the presence of rhodanese is reported in higher plant tissuesother than the leaves. Identity has been established betweenrhodanese from peel, leaves, and flesh of the cassava plant.The enzyme is inhibited by cyanide in the absence of thiosuiphateor cysteine. Rhodanese is suggested to play a role in the detoxificationof cyanide in cassava.     

Phylogeny,classification and evolution of the water scavenger beetle tribe Hydrobiusini inferred from morphology and molecules (Coleoptera: Hydrophilidae: Hydrophilinae)

The water scavenger beetle tribe Hydrobiusini contains 47 species in eight genera distributed worldwide. Most species of the tribe are aquatic, although several species are known to occur in waterfalls or tree mosses. Some members of the tribe are known to communicate via underwater stridulation. While recent morphological and molecular‐based phylogenies have affirmed the monophyly of the tribe as currently circumscribed, doubts remain about the monophyly of included genera. Here we use morphological and molecular data to infer a species‐level phylogeny of the Hydrobiusini. The monophyly of the tribe is decisively supported, as is the monophyly of most genera. The genus Hydrobius was found to be polyphyletic, and as a result the genus Limnohydrobius stat. rev. is removed from synonymy with Hydrobius, yielding three new combinations: L. melaenus comb.n. , L. orientalis comb.n. , and L. tumbius comb.n. Recent changes to the species‐level taxonomy of Hydrobius are reviewed. The morphology of the stridulatory apparatus has undergone a single remarkable transformation within the lineage, from a simple, unmodified pars stridens to one that is highly organized and complex. We present an updated key to genera, revised generic diagnoses and a list of the known distributions for all species within the tribe.     

Evolution of the tooth enamel microstructure in the earliest proboscideans (Mammalia)

Microstructural features of the mammalian tooth enamel are rarely used to construct phylogenies, although macromorphological characters of the dentition figure prominently in phylogenetic analysis. In order to test the phylogenetic significance of the enamel microstructures, we investigate here the earliest proboscideans recently found in the Early Palaeogene of Africa (e.g. Phosphatherium , Daouitherium , Khamsaconus , and Numidotherium ). The results are discussed in the light of the recent advances concerning the intra- and interordinal relationships of the Proboscidea. We also consider other basal paenungulates such as 'anthracobunids', embrithopods, and hyraxes. The analysed microstructures suggest that the enamel ancestral morphotype of paenungulates was primitive for eutherian mammals, consisting in radial enamel. Some basal proboscideans developed decussations of prisms in Hunter-Schreger bands (HSB), as did most of the medium to large-sized mammals. More evolved proboscideans developed very complex enamel, the 3-D enamel, which represents an apomorphy for the group. The three-layered Schmelzmuster, typical of the elephantoids (3-D enamel, HSB, and radial enamel), is acquired during the late Eocene with the enigmatic ' Numidotherium ' savagei . This species is here considered as an advanced proboscidean along with Moeritherium -Deinotheriidae-Elephantiformes. The peculiar enamel of elephantoids arose step by step. Although homoplasy and mosaic evolution occur, the enamel microstructures represent an important source of new dental characters for phylogenetic reconstructions. As macromorphological characters testified, the diversity of the enamel microstructures observed in the various basal proboscideans illustrates an unexpected early diversity of the order in Africa.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 149 , 611–628.     

Brain size of the lion (Panthera leo) and the tiger (P. tigris): implications for intrageneric phylogeny, intraspecific differences and the effects of captivity

Intraspecific encephalization of the lion and the tiger is investigated for the first time using a very large sample. Using cranial volume as a measure of brain size, the tiger has a larger brain relative to greatest length of skull than the lion, the leopard and the jaguar. The Asian lion has a relatively much smaller brain compared with those of sub-Saharan lions, between which there are few differences. The Balinese and Javan tigers had relatively larger brains compared with those of Malayan and Sumatran tigers, even although these four putative subspecies occupy adjacent ranges in south-eastern Asia. Differences in brain size do not appear to correlate with any known differences in behaviour and ecology and, therefore, may reflect only chance differences in intrageneric and intraspecific phylogeny. However, captive-bred big cats generally have a reduced brain size compared with that of wild animals, so that an animal's life history and living conditions may affect brain size and, hence, functional or environmental explanations should be considered when linking brain size differences to intraspecific phylogenies.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 85–93.     

Parallel changes in genetic diversity and species diversity following a natural disturbance

We examined the spatial and temporal variation of species diversity and genetic diversity in a metacommunity comprising 16 species of freshwater gastropods. We monitored species abundance at five localities of the Ain river floodplain in southeastern France, over a period of four years. Using 190 AFLP loci, we monitored the genetic diversity of Radix balthica , one of the most abundant gastropod species of the metacommunity, twice during that period. An exceptionally intense drought occurred during the last two years and differentially affected the study sites. This allowed us to test the effect of natural disturbances on changes in both genetic and species diversity. Overall, local (alpha) diversity declined as reflected by lower values of gene diversity H _S and evenness. In parallel, the among-sites (beta) diversity increased at both the genetic ( F _ST) and species ( F _STC) levels. These results suggest that disturbances can lead to similar changes in genetic and community structure through the combined effects of selective and neutral processes.     

Partial Purification and Characterization of Polyphenol Oxidase from Cocoyam, Xanthosoma sagittifolium

Polyphenol oxidase has been partially purified from Xanthosomasagittifolium. The enzyme showed activity towards pyrogallol,DL-ß-3,4-dihydroxyphenylalanine (DOPA) and catechol.Of these three, pyrogallol was the best substrate. The effectsof various compounds as inhibitors of the reaction catalysedby the enzyme were tested. p-Nitrophenol competitively inhibitedthe binding of both catechol and pyrogallol to the enzyme. Inhibitionby the substrate analogue, p-cresol was of the mixed type whilethiourea and diethyldithiocarbamate inhibited the enzyme uncompetitively.The approximate molecular weight of the enzyme determined bygel filtration was 47 000.     

Wildlife–water quality interactions in the Serengeti National Park, Tanzania

Surveys of water quality in the surface waters in the Serengeti National Park were undertaken in both the wet and dry seasons of 1996. Most rivers were ponded, with ponds having a flushing time of 1 month in the wet season and zero flushing in the dry season. pH values varied spatially from extremely alkaline conditions (pH>10) in the southern plains to acidic conditions in the northern region (pH=5·9). In the southern plains at the end of the dry season the salinity of surface waters was high (5–17‰) while there was abundant surface water and the zebras and wildebeest had started to migrate away, a finding suggesting excessive salinity may be the trigger initiating the annual migration. Most surface waters were heavily eutrophicated as a result of animal dung. As a result, the dissolved oxygen concentration near the surface fluctuated widely between 1 and 200% of saturation, smaller values occurring deeper in the water column. Stirring and mechanical aeration by hippos, crocodiles and mammals crossing the rivers prevented the formation of anoxic conditions. The oxygen stress was measurably lessened in wetland‐fringed water bodies as a result of filtering. Light penetration was high (≥10 cm) in saline waters as a result of flocculation enhanced by bacteria and vegetation detritus, elsewhere the euphotic zone was less than 1 cm thick and the waters generally inhospitable to aquatic life. The discontinuity between wooded savanna and grassland coincides with the occurrence of alkaline, high salinity waters in the dry season.