关键词： Mallee   Cenozoic   Mammal   Paleoclimate   Paleobotany  

摘要： Mallee is an endemic Australian woodland and shrubland of semi-arid, summer-dry regions between dry woodland and desert shrubland. In other parts of the world, such as Africa and the Americas, such climatic regions support grassland ecosystems. Using Australian and African climofunctions and models gives very different reconstructions of paleoclimate (subhumid versus perhumid) and paleovegetation (woodland versus rainforest) for North American fossil mammal faunas before Cenozoic evolution of grassland ecosystems. Modern mammal faunas of Africa and Australia have different ecological spectra of taxonomic units, body size, feeding, and locomotion of species of mammals on precipitation gradients. Gradients in proportions of such categories yield transfer functions for mean annual precipitation from percent species of Artiodactyla or Macropodidae, percent species of moderately large animals (45-180 kg), percent species of arboreal mammals, and percent species of grazers. These transfer functions can be applied to fossil mammal faunas to estimate paleoprecipitation in Africa. Australia and North America. Modern transfer functions match well paleoprecipitation estimates based on depth to calcic horizons in paleosols at the same localities in Kenya and inland Australia back through the Miocene. For fossil mammal faunas of the Rocky Mountain region of North America, African transfer functions fail, but Australian transfer functions predict paleoprecipitation back to the Cretaceous-Tertiary boundary (66 Ma). Furthermore, modern mallee soils investigated in this study closely match Cretaceous to Eocene paleosols of the Rocky Mountains. Extinct mallee-like vegetation, such as pori woodlands of Kenya and cunhaka woodlands (newly defined) of the Rocky Mountains better explains the dominance of small, nocturnal, insectivorous, arboreal mammals of Paleogene and Mesozoic mammal faunas, than comparisons with African grassland or rainforest faunas. (c) 2012 Elsevier B.V. All rights

关键词： Cricetidae   Cerrado   Geometric morphometrics   Locomotory mode   Vertical stratification  

摘要： We investigated the relation between the footprint shape of the fore and hind feet of sigmodontine rodents and their levels of arboreal activity. Footprint shape was obtained by analyzing the impressions left by identified animals captured in the field after being forced to pass through ink-tracking tunnels or by pressing their previously inked feet on a paper sheet. We used geometric morphometric techniques that use superimposition of landmarks (centers of the pads) to obtain footprint shape variables, which were reduced using multivariate analysis (principal component analysis). Arboreal activity was inferred on the basis of the proportions of individuals captured in arboreal traps (1.5-2.5 m height). Regression analysis of body size and the variable that best represented the footprint shapes (first principal component-PC1) did not indicate significant allometric effects on such shapes. We did not detect any significant phylogenetic effects on the arboreal activity of the rodents, either. The results indicated that the PC1 concerning footprint shapes of ten sigmodontine rodents efficiently reflects the degree of use of arboreal strata by these animals. The species studied showed different levels of arboreal activity and their hind footprints (r(2) = 0.94) were better indicators of arboreality than the fore footprints (r(2) = 0.53). These findings suggest a likely trade off for the fore feet functions. Such functions are probably not strictly related to locomotion. Other biomechanical functions (e.g., shock absorption) and/or manipulation (e.g., food manipulation and grooming) may exert relatively greater influence on the shape of fore feet.

关键词： biodiversity   cetoniines   faunal lists   new records   protected areas   West Africa  

摘要： The cetoniine fauna of Ghana (Coleoptera: Scarabaeidae: Cetoniinae, excluding the tribes Valgini and Trichiini) is presented based on results from the Ghana Insect Project (GIP). Data from 1,571 specimens including the species and number found at each of 16 collecting sites, collecting methods, months collected, 'common' species and habitat associations are presented. The fauna now consists of 109 species in 51 genera. Previously known distributions and specimen label data are given for 31 species (including Genuchina, a subtribe of Cremastocheilini) recorded from Ghana for the first time. Comparisons with the works of Endrödi (1973, 1976) and Joly (2001) are made and several misidentifications are annotated and corrected. GIP results suggest moist evergreen/semi-deciduous forest and Guinea savanna/semi-deciduous forest are species-rich habitats. Faunal lists for four protected areas (Ankasa Resource Reserve, Atewa Range Forest Reserve, Bia National Park and Mole National Park) sampled by both the GIP and Joly (2001, 2011) are presented. PAST (Hammer et al., 2001) was used to estimate GIP inventory completeness through individual rarefaction. EstimateS (Colwell, 2009) was used to estimate total species richness using several classic nonparametric species richness estimators. Based on a data matrix of species abundances from each of the 16 GIP sites, the Chao 2 estimator stabilizes at ca. 113 taxa, and the jackknife 2 estimator at ca. 130 taxa. Richness estimates based on a broader, incidence-based matrix from all three sources GIP, Endrödi (1973, 1976) and Joly (2001, 2011) were: Chao 2 = 153, jackknife 1 = 157, jackknife 2 = 173. Additional sampling in under-sampled habitats such as wet and moist evergreen forest and Guinea savanna, and during the dry and early wet seasons should yield additional species. [ABSTRACT FROM AUTHOR]

关键词： Anti-predator behavior   Group living   Impala   Patch quality   Vigilance   Visibility  

摘要： Vigilance allows individuals to escape from predators, but it also reduces time for other activities which determine fitness, in particular resource acquisition. The principles determining how prey trade time between the detection of predators and food acquisition are not fully understood, particularly in herbivores because of many potential confounding factors (such as group size), and the ability of these animals to be vigilant while handling food. We designed a fertilization experiment to manipulate the quality of resources, and compared awareness (distinguishing apprehensive foraging and vigilance) of wild impalas () foraging on patches of different grass height and quality in a wilderness area with a full community of predators. While handling food, these animals can allocate time to other functions. The impalas were aware of their environment less often when on good food patches and when the grass was short. The animals spent more time in apprehensive foraging when grass was tall, and no other variable affected apprehensive behavior. The probability of exhibiting a vigilance posture decreased with group size. The interaction between grass height and patch enrichment also affected the time spent in vigilance, suggesting that resource quality was the main driver when visibility is good, and the risk of predation the main driver when the risk is high. We discuss various possible mechanisms underlying the perception of predation risk: foraging strategy, opportunities for scrounging, and inter-individual interference. Overall, this experiment shows that improving patch quality modifies the trade-off between vigilance and foraging in favor of feeding, but vigilance remains ultimately driven by the visibility of predators by foragers within their feeding patches.

关键词： Competitor-free space   Diet breadth   Insect herbivory   Pasture reforestation   Tree diversity  

摘要： Heterospecific neighbors may reduce damage to a focal plant by lowering specialist herbivore loads (associational resistance hypothesis), or enhance damage by increasing generalist herbivore loads (associational susceptibility hypothesis). We tested the associational effects of tree diversity on herbivory patterns of the tropical focal tree in an experimental plantation setup, which contained tree monocultures and mixed stands. We found higher herbivore damage to at higher tree diversity, indicating that did not benefit from associational resistance but rather experienced associational susceptibility. The specific consideration of the two dominant insect herbivore species of , the specialist chrysomelid and the specialist pyralid , facilitated understanding of the detected damage patterns Tree diversity exerted opposite effects on tree infestation by the two herbivores. These findings point to resource concentration effects for the chrysomelid beetle (favored by tree monoculture) and to resource dilution effects for the pyralid caterpillar (favored by tree mixture) as underlying mechanisms of herbivore distribution. A strong contribution of the pyralid to overall damage patterns in diversified stands suggests that associational susceptibility may not necessarily be related to higher abundances of generalist herbivores but may also result from specialized herbivores affected by resource dilution effects. Thus, the identity and biology of herbivore species has to be taken into account when attempting to predict damage patterns in forest ecosystems.

关键词： Mycobacterium avium complex   Mycobacterium tuberculosis   Phylogenetic analysis   Amoebas   Mycobacterium ulcerans   Dictyostelium discoideum   Gene prediction   Legionella pneumophila  

摘要： Free-living protozoa allow horizontal gene transfer with and between the microorganisms that they host. They host mycobacteria for which the sources of transferred genes remain unknown. Using BLASTp, we searched within the genomes of 15 mycobacteria for homologous genes with 34 amoeba-resistant bacteria and the free-living protozoa Dictyostelium discoideum. Subsequent phylogenetic analysis of these sequences revealed that eight mycobacterial open-reading frames (ORFs) were probably acquired via horizontal transfer from beta-and gamma-Proteobacteria and from Firmicutes, but the transfer histories could not be reliably established in details. One further ORF encoding a pyridine nucleotide disulfide oxidoreductase (pyr-redox) placed non-tuberculous mycobacteria in a clade with Legionella spp., Francisella spp., Coxiella burnetii, the ciliate Tetrahymena thermophila and D. discoideum with a high reliability. Co-culturing Mycobacterium avium and Legionella pneumophila with the amoeba Acanthamoeba polyphaga demonstrated that these two bacteria could live together in amoebae for five days, indicating the biological relevance of intra-amoebal transfer of the pyr-redox gene. In conclusion, the results of this study support the hypothesis that protists can serve as a source and a place for gene transfer in mycobacteria.

关键词： elk   plant demography   snowpack   species interactions   Yellowstone  

摘要： Altered species interactions are difficult to predict and yet may drive the response of ecological communities to climate change. We show that declining snowpack strengthens the impacts of a generalist herbivore, elk (Cervus elaphus), on a common tree species. Thick snowpack substantially reduces elk visitation to sites;aspen (Populus tremuloides) shoots in these areas experience lower browsing rates, higher survival and enhanced recruitment. Aspen inside herbivore exclosures have greatly increased recruitment, particularly at sites with thick snowpack. We suggest that long-term decreases in snowpack could help explain a widespread decline of aspen through previously unconsidered relationships. More generally, reduced snowpack across the Rocky Mountains, combined with rising elk populations, may remove the conditions needed for recruitment of this ecologically important tree species. These results highlight that herbivore behavioural responses to altered abiotic conditions are critical determinants of plant persistence. Predictions of climate change impacts must not overlook the crucial importance of species interactions.

关键词： Cretaceous-Tertiary   historical biogeography   lineage diversification   rainforest adaptation   overseas dispersal  

摘要： The geographic and temporal origins of Madagascar's biota have long been in the center of debate. We reconstructed a time-tree including nearly all native nonflying and nonmarine vertebrate clades present on the island, from DNA sequences of two single-copy protein-coding nuclear genes (BDNF and RAG1) and a set of congruent time constraints. Reconstructions calculated with autocorrelated or independent substitution rates over clades agreed in placing the origins of the 31 included clades in Cretaceous to Cenozoic times. The two clades with sister groups in South America were the oldest, followed by those of a putative Asian ancestry that were significantly older than the prevalent clades of African ancestry. No colonizations from Asia occurred after the Eocene, suggesting that dispersal and vicariance of Asian/Indian groups were favored over a comparatively short period during, and shortly after, the separation of India and Madagascar. Species richness of clades correlates with their age but those clades that have a large proportion of species diversity in rainforests are significantly more species-rich. This finding suggests an underlying pattern of continuous speciation through time in Madagascar's vertebrates, with accelerated episodes of adaptive diversification in those clades that succeeded radiating into the rainforests.

关键词： GENOMICS   MOLECULAR genetics   GENOMES   DNA   GENES  

摘要： Phylogenomics offers the potential to fully resolve the Tree of Life, but increasing genomic coverage also reveals conflicting evolutionary histories among genes, demanding new analytical strategies for elucidating a single history of life. Here, we outline a phylogenomic approach using a novel class of phylogenetic markers derived from ultraconserved elements and flanking DNA. Using species-tree analysis that accounts for discord among hundreds of independent loci, we show that this class of marker is useful for recovering deep-level phylogeny in placental mammals. In broad outline, our phylogeny agrees with recent phylogenomic studies of mammals, including several formerly controversial relationships. Our results also inform two outstanding questions in placental mammal phylogeny involving rapid speciation, where species-tree methods are particularly needed. Contrary to most phylogenomic studies, our study supports a first-diverging placental mammal lineage that includes elephants and tenrecs (Afrotheria). The level of conflict among gene histories is consistent with this basal divergence occurring in or near a phylogenetic "anomaly zone" where a failure to account for coalescent stochasticity will mislead phylogenetic inference. Addressing a long-standing phylogenetic mystery, we find some support from a high genomic coverage data set for a traditional placement of bats (Chiroptera) sister to a clade containing Perissodactyla, Cetartiodactyla, and Carnivora, and not nested within the latter clade, as has been suggested recently, although other results were conflicting. One of the most remarkable findings of our study is that ultraconserved elements and their flanking DNA are a rich source of phylogenetic information with strong potential for application across Amniotes.