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https://www.readbyqxmd.com/read/28434541/phytoliths-indicate-significant-arboreal-cover-at-sahelanthropus-type-locality-tm266-in-northern-chad-and-a-decrease-in-later-sites
#1
Alice Novello, Doris Barboni, Florence Sylvestre, Anne-Elisabeth Lebatard, Christine Paillès, Didier L Bourlès, Andossa Likius, Hassane Taisso Mackaye, Patrick Vignaud, Michel Brunet
We analyzed phytolith and diatom remains preserved at 45 Miocene and Pliocene localities dated between 8 and 1 Ma in northern Chad (16-17°N). Some of these localities yielded cranial remains, lower jaws, and teeth of the hominin species Australopithecus bahrelghazali (∼3.6 Ma) and Sahelanthropus tchadensis (∼7 Ma). Of the 111 sediment samples analyzed, 41 yielded phytoliths, 20 yielded diatoms, and seven yielded both phytoliths and diatoms. Freshwater planktonic and tychoplanktonic diatom species, indicative of lacustrine conditions, are dominant (>91%) in the samples...
May 2017: Journal of Human Evolution
https://www.readbyqxmd.com/read/28425424/spatial-distribution-of-batrachochytrium-dendrobatidis-in-south-american-caecilians
#2
Carolina Lambertini, C Guilherme Becker, Cecilia Bardier, Domingos da Silva Leite, Luís Felipe Toledo
The amphibian-killing fungus Batrachochytrium dendrobatidis (Bd) is linked to population declines in anurans and salamanders globally. To date, however, few studies have attempted to screen Bd in live caecilians; Bd-positive caecilians have only been reported in Africa and French Guiana. Here, we performed a retrospective survey of museum preserved specimens to (1) describe spatial patterns of Bd infection in Gymnophiona across South America and (2) test whether areas of low climatic suitability for Bd in anurans predict Bd spatial epidemiology in caecilians...
April 20, 2017: Diseases of Aquatic Organisms
https://www.readbyqxmd.com/read/28425026/photosynthetic-responses-to-temperature-across-leaf-canopy-ecosystem-scales-a-15-year-study-in-a-californian-oak-grass-savanna
#3
Siyan Ma, Jessica L Osuna, Joseph Verfaillie, Dennis D Baldocchi
Ecosystem CO2 fluxes measured with eddy-covariance techniques provide a new opportunity to retest functional responses of photosynthesis to abiotic factors at the ecosystem level, but examining the effects of one factor (e.g., temperature) on photosynthesis remains a challenge as other factors may confound under circumstances of natural experiments. In this study, we developed a data mining framework to analyze a set of ecosystem CO2 fluxes measured from three eddy-covariance towers, plus a suite of abiotic variables (e...
April 19, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28414784/savanna-elephant-numbers-are-only-a-quarter-of-their-expected-values
#4
Ashley S Robson, Morgan J Trimble, Andrew Purdon, Kim D Young-Overton, Stuart L Pimm, Rudi J van Aarde
Savannas once constituted the range of many species that human encroachment has now reduced to a fraction of their former distribution. Many survive only in protected areas. Poaching reduces the savanna elephant, even where protected, likely to the detriment of savanna ecosystems. While resources go into estimating elephant populations, an ecological benchmark by which to assess counts is lacking. Knowing how many elephants there are and how many poachers kill is important, but on their own, such data lack context...
2017: PloS One
https://www.readbyqxmd.com/read/28403506/parasite-responses-to-large-mammal-loss-in-an-african-savanna
#5
Sara Weinstein, Georgia Titcomb, Bernard Agwanda, Corinna Riginos, Hillary Young
Biodiversity loss can alter disease transmission; however, the magnitude and direction of these effects vary widely across ecosystems, scales, and pathogens. Here we experimentally examine the effects of one of the most globally pervasive patterns of biodiversity decline, the selective loss of large wildlife, on infection probability, intensity and population size of a group of common rodent-borne parasites - macroparasitic helminths. Consistent with previous work on vector-borne pathogens, we found that large wildlife removal causes strong and systematic increases of rodent-borne parasites, largely due to increases in rodent density, as rodents are released from competition with larger herbivores...
April 12, 2017: Ecology
https://www.readbyqxmd.com/read/28396440/floodplains-as-an-achilles-heel-of-amazonian-forest-resilience
#6
Bernardo M Flores, Milena Holmgren, Chi Xu, Egbert H van Nes, Catarina C Jakovac, Rita C G Mesquita, Marten Scheffer
The massive forests of central Amazonia are often considered relatively resilient against climatic variation, but this view is challenged by the wildfires invoked by recent droughts. The impact of such fires that spread from pervasive sources of ignition may reveal where forests are less likely to persist in a drier future. Here we combine field observations with remotely sensed information for the whole Amazon to show that the annually inundated lowland forests that run through the heart of the system may be trapped relatively easily into a fire-dominated savanna state...
April 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28394937/the-brazilian-freshwater-wetscape-changes-in-tree-community-diversity-and-composition-on-climatic-and-geographic-gradients
#7
Florian Wittmann, Márcia C M Marques, Geraldo Damasceno Júnior, Jean Carlos Budke, Maria T F Piedade, Astrid de Oliveira Wittmann, Juan Carlos Montero, Rafael L de Assis, Natália Targhetta, Pia Parolin, Wolfgang J Junk, J Ethan Householder
Wetlands harbor an important compliment of regional plant diversity, but in many regions data on wetland diversity and composition is still lacking, thus hindering our understanding of the processes that control it. While patterns of broad-scale terrestrial diversity and composition typically correlate with contemporary climate it is not clear to what extent patterns in wetlands are complimentary, or conflicting. To elucidate this, we consolidate data from wetland forest inventories in Brazil and examine patterns of diversity and composition along temperature and rainfall gradients spanning five biomes...
2017: PloS One
https://www.readbyqxmd.com/read/28390027/insects-associated-with-pig-carrion-in-two-environments-of-the-brazilian-savanna
#8
L S de Faria, M L Paseto, M S Couri, C A Mello-Patiu, J Mendes
Studies of carrion fauna have increased in Brazil and have contributed to the knowledge of this fauna in the national territory. Brazil has continental dimensions and presents various biomes in its territorial area. Most of the carrion fauna have seldom been studied, and this is especially true for the Savanna or "Cerrado." The present research examined the fauna visiting carrion in two environments and two seasons in a rural area situated in a region of Cerrado in southeastern Brazil. The two environments studied were a pasture and a fragment of semi-deciduous forest...
April 8, 2017: Neotropical Entomology
https://www.readbyqxmd.com/read/28388640/a-savanna-response-to-precipitation-intensity
#9
Ryan S Berry, Andrew Kulmatiski
As the atmosphere warms, precipitation events are becoming less frequent but more intense. A three-year experiment in Kruger National Park, South Africa, found that fewer, more intense precipitation events encouraged woody plant encroachment. To test whether or not these treatment responses persisted over time, here, we report results from all five years of that experiment. Grass growth, woody plant growth, total fine root number and area and hydrologic tracer uptake by grasses and woody plants were measured in six treated plots (8 m by 8 m) and six control plots...
2017: PloS One
https://www.readbyqxmd.com/read/28369906/the-effects-of-ant-nests-on-soil-fertility-and-plant-performance-a-meta-analysis
#10
Alejandro G Farji-Brener, Victoria Werenkraut
Ants are recognized as one of the major sources of soil disturbance worldwide. However, this view is largely based on isolated studies and qualitative reviews. Here, for the first time, we quantitatively determined whether ant nests affect soil fertility and plant performance, and identified the possible sources of variation of these effects. Using Bayesian mixed-models meta-analysis we tested the hypotheses that ant effects on soil fertility and plant performance depend on the substrate sampled, ant feeding type, latitude, habitat and the plant response variable measured...
March 31, 2017: Journal of Animal Ecology
https://www.readbyqxmd.com/read/28369733/feeding-in-fear-how-adult-male-western-chimpanzees-pan-troglodytes-verus-adjust-to-predation-and-savanna-habitat-pressures
#11
Stacy Lindshield, Brent J Danielson, Jessica M Rothman, Jill D Pruetz
OBJECTIVES: We evaluated risk-sensitive foraging in adult male western chimpanzees (Pan troglodytes verus) occupying a savanna environment at Fongoli, Senegal. The aim of this study was to determine how the risks of predation and heat stress influenced their behavior while feeding on a key food, fruit of the baobab tree (Adansonia digitata). MATERIALS AND METHODS: Proximity of fruiting baobab trees to anthropogenic landmarks were compared to food intake, feeding rate, and behavioral indicators of fear in adult males (N = 11) at Fongoli...
March 28, 2017: American Journal of Physical Anthropology
https://www.readbyqxmd.com/read/28357641/-distribution-of-species-and-kdr-gene-frequency-among-anopheles-gambiae-s-s-and-anopheles-coluzzii-populations-in-five-agricultural-sites-in-c%C3%A3-te-d-ivoire
#12
E Tia, M Chouaibou, C N G Gbalégba, A M O Boby, M Koné, A K Kadjo
The resistance of Anopheles gambiae s.l. to insecticides constitutes a concern for the programs of malaria control because it can be an obstacle to effective control of the vectors. The follow-up of this resistance is a priority to work out strategies of management and to preserve the means of that major malaria vector control activities. The general objective of this study is to identify the species within An. gambiae s.l., and to determine the frequency of the Kdr gene in An. gambiae s.s. and An. coluzzii in five agricultural sites in Ivory Coast: an urban site, two semirural sites (coffee-trees/cacao-trees, orchard) and two rural sites (rice site and a traditional village without agricultural insecticide)...
March 29, 2017: Bulletin de la Société de Pathologie Exotique
https://www.readbyqxmd.com/read/28355387/effects-of-soil-and-space-on-the-woody-species-composition-and-vegetation-structure-of-three-cerrado-phytophysiognomies-in-the-cerrado-amazon-transition
#13
L Maracahipes-Santos, E Lenza, J O Santos, H A Mews, B Oliveira
The Cerrado Biome is considered one of the world's biodiversity hotspots because of its rich biodiversity, the high level of endemism and the increasing threat. The Cerrado is composed by a mosaic of different vegetation types, including physiognomies that vary from grasslands (campo limpo) to savannas (typical cerrado or cerrado sensu stricto) and cerrado woodlands (cerradão). However, the factors that determine the composition of the Cerrado's flora and the structure of the physiognomies that compose this biome are still poorly understood...
March 16, 2017: Brazilian Journal of Biology, Revista Brasleira de Biologia
https://www.readbyqxmd.com/read/28355223/pre-control-relationship-of-onchocercal-skin-disease-with-onchocercal-infection-in-guinea-savanna-northern-nigeria
#14
Michele E Murdoch, Ian E Murdoch, Jennifer Evans, Haliru Yahaya, Ngozi Njepuome, Simon Cousens, Barrie R Jones, Adenike Abiose
BACKGROUND: Onchocerca volvulus infection can result in blindness, itching and skin lesions. Previous research concentrated on blindness. METHODS: A clinical classification system of the cutaneous changes in onchocerciasis was used for the first time in this study within the context of an early ivermectin drug trial in the savanna region of Kaduna State, northern Nigeria. Skin examinations were performed in 6,790 individuals aged 5+ years in endemic communities and 1,343 individuals in nonendemic communities...
March 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28342277/climatic-variation-modulates-the-indirect-effects-of-large-herbivores-on-small-mammal-habitat-use
#15
Ryan A Long, Alois Wambua, Jacob R Goheen, Todd M Palmer, Robert M Pringle
Large mammalian herbivores (LMH) strongly shape the composition and architecture of plant communities. A growing literature shows that negative direct effects of LMH on vegetation frequently propagate to suppress the abundance of smaller consumers. Indirect effects of LMH on the behaviour of these consumers, however, have received comparatively little attention despite their potential ecological significance. We sought to understand (i) how LMH indirectly shape small-mammal habitat use by altering the density and distribution of understory plants; (ii) how these effects vary with climatic context (here, seasonality in rainfall); and (iii) the extent to which behavioural responses of small mammals are contingent upon small-mammal density...
March 25, 2017: Journal of Animal Ecology
https://www.readbyqxmd.com/read/28334265/evaluation-of-malaise-and-yellow-pan-trap-performance-to-assess-velvet-ant-hymenoptera-mutillidae-diversity-in-a-neotropical-savanna
#16
C R Vieira, C Waichert, K A Williams, J P Pitts
Given the global biodiversity crisis, it is crucial to identify methods best suited for conducting inventories. We evaluated the relative merits of Malaise traps (MT) and ground-level yellow pan traps (YPT) to sample male velvet ants (Hymenoptera: Mutillidae) in a Neotropical savanna biodiversity hotspot. We compared richness, number of captures, evenness, composition, and body size of male velvet ants (Hymenoptera: Mutillidae) sampled with both methods in four sites at Parque Nacional da Chapada dos Veadeiros, central Brazil, during 19 d...
April 1, 2017: Environmental Entomology
https://www.readbyqxmd.com/read/28323541/3d-technology-of-sony-bloggie-has-no-advantage-in-decision-making-of-tennis-serve-direction-a-randomized-placebo-controlled-study
#17
Sicong Liu, Jason Ritchie, Camilo Sáenz-Moncaleano, Savanna K Ward, Cody Paulsen, Tyler Klein, Oscar Gutierrez, Gershon Tenenbaum
This study aimed at exploring whether 3D technology enhances tennis decision-making under the conceptual framework of human performance model. A 3 (skill-level: varsity, club, recreational) × 3 (experimental condition: placebo, weak 3D [W3D], strong 3D [S3D]) between-participant design was used. Allocated to experimental conditions by a skill-level stratified randomization, 105 tennis players judged tennis serve direction from video scenarios and rated their perceptions of enjoyment, flow, and presence during task performance...
March 21, 2017: European Journal of Sport Science
https://www.readbyqxmd.com/read/28303013/addressing-rainfall-data-selection-uncertainty-using-connections-between-rainfall-and-streamflow
#18
Morgan C Levy, Avery Cohn, Alan Vaz Lopes, Sally E Thompson
Studies of the hydroclimate at regional scales rely on spatial rainfall data products, derived from remotely-sensed (RS) and in-situ (IS, rain gauge) observations. Because regional rainfall cannot be directly measured, spatial data products are biased. These biases pose a source of uncertainty in environmental analyses, attributable to the choices made by data-users in selecting a representation of rainfall. We use the rainforest-savanna transition region in Brazil to show differences in the statistics describing rainfall across nine RS and interpolated-IS daily rainfall datasets covering the period of 1998-2013...
March 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28301475/multiple-ecosystem-services-in-a-working-landscape
#19
Danny J Eastburn, Anthony T O'Geen, Kenneth W Tate, Leslie M Roche
Policy makers and practitioners are in need of useful tools and models for assessing ecosystem service outcomes and the potential risks and opportunities of ecosystem management options. We utilize a state-and-transition model framework integrating dynamic soil and vegetation properties to examine multiple ecosystem services-specifically agricultural production, biodiversity and habitat, and soil health-across human created vegetation states in a managed oak woodland landscape in a Mediterranean climate. We found clear tradeoffs and synergies in management outcomes...
2017: PloS One
https://www.readbyqxmd.com/read/28295840/climatic-changes-can-drive-the-loss-of-genetic-diversity-in-a-neotropical-savanna-tree-species
#20
Jacqueline S Lima, Liliana Ballesteros-Mejia, Matheus S Lima-Ribeiro, Rosane G Collevatti
The high rates of future climatic changes, compared with the rates reported for past changes, may hamper species adaptation to new climates or the tracking of suitable conditions, resulting in significant loss of genetic diversity. Trees are dominant species in many biomes and because they are long-lived, they may not be able to cope with ongoing climatic changes. Here, we coupled Ecological Niche Modelling (ENM) and genetic simulations to forecast the effects of climatic changes on the genetic diversity and the structure of genetic clusters...
March 13, 2017: Global Change Biology
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