86 Works

Data from: Functional MRI in the Nile crocodile: a new avenue for evolutionary neurobiology

Mehdi Behroozi, Brendon K. Billings, Xavier Helluy, Paul R. Manger, Onur Güntürkün & Felix Ströckens
Crocodilians are important for understanding the evolutionary history of amniote neural systems as they are the nearest extant relatives of modern birds and share a stem amniote ancestor with mammals. Although the crocodilian brain has been investigated anatomically, functional studies are rare. Here we employed fMRI, never tested in poikilotherms, to investigate crocodilian telencephalic sensory processing. Juvenile Crocodylus niloticus were placed in a 7T MRI scanner to record BOLD signal changes during presentation of visual...

Quality of Life Survey I 2009

Reasons for extreme Th/U zoning of zircon in magmatic rocks: examples from the Bushveld Complex

Armin Zeh , Dominik Gudelius & Allan H Wilson
Zircons of magmatic rocks can show enormous variations in Th/U ratios (0.2 to 100) and extreme Th/U zoning. We present data from felsic and mafic rocks of the Bushveld Complex in South Africa. Zircon grains in mafic cumulate rocks reveal Th/U ratios up to 70, those in felsic rocks barely exceed 1.0. In mafic rocks zircon mostly occur together with Rt-Bt-Kfs-Qtz in intercumulus domains, and crystallized during final magma cooling between 900 and 700°C, after...

Data from: Continent-level drivers of African pyrodiversity

Gareth P. Hempson, Catherine L. Parr, Sally Archibald, T. Michael Anderson, Colin J. Courtney Mustaphi, Andrew P. Dobson, Jason E. Donaldson, Thomas A. Morrison, James Probert & Colin M. Beale
Pyrodiversity, which describes fire variability over space and time, is believed to increase habitat heterogeneity and thereby promote biodiversity. However, to date there is no standardised metric for quantifying pyrodiversity, and so broad geographic patterns and drivers of pyrodiversity remain unexplored. We present the first generalizable method to quantify pyrodiversity, and use it to address the fundamental questions of what drives pyrodiversity, which fire attributes constrain pyrodiversity under different conditions, and whether pyrodiversity is spatial...

Data from: Interactive effects of exogenous and endogenous factors on demographic rates of an African rodent

Chloé R. Nater, Cindy I. Canale, Koen J. Van Benthem, Chi-Hang Yuen, Ivana Schoepf, Neville Pillay, Arpat Ozgul & Carsten Schradin
Exogenous and endogenous environmental factors can have simultaneous additive as well as interacting effects on life-history traits. Ignoring such interactions can lead to a biased understanding of variability in demographic rates and consequently population dynamics. These interactions have been the focus of decades-long debates on the mechanisms underlying small mammal population fluctuations. They have often been studied indirectly through seasonal effects, but studies considering them directly and more mechanistically are rare. We investigated the joint...

Data from: Fire frequency drives habitat selection by a diverse herbivore guild impacting top–down control of plant communities in an African savanna

Deron E. Burkepile, Dave I. Thompson, Richard W. S. Fynn, Sally E. Koerner, Stephanie Eby, Navashni Govender, Nicole Hagenah, Nathan P. Lemoine, Katherine J. Matchett, Kevin R. Wilcox, Scott L. Collins, Kevin P. Kirkman, Alan K. Knapp & Melinda D. Smith
In areas with diverse herbivore communities such as African savannas, the frequency of disturbance by fire may alter the top–down role of different herbivore species on plant community dynamics. In a seven year experiment in the Kruger National Park, South Africa, we examined the habitat use of nine common herbivore species across annually burned, triennially burned and unburned areas. We also used two types of exclosures (plus open access controls) to examine the impacts of...

Data from: The Triassic Mesophlebiidae, a little closer to the crown of the Odonata (Insecta) than other ‘triassolestids’

Ayla Tierney, Isabelle Deregnaucourt, John M. Anderson, Paul Tierney, Torsten Wappler & Olivier Béthoux
Two new, subcomplete forewings belonging to the ‘triassolestid assemblage’, a group of Triassic stem-relatives of dragon- and damselflies (Odonata), are described. One, recovered from Australia (Aranbanga Volcanic Group), belongs to Mesophlebia antinodalis Tillyard, 1916, previously documented on the basis of two very incomplete wings. The other, recovered from South Africa (Molteno Formation), is assigned to a new species, Mesophlebia elegans sp. nov. The new data allow a reconsideration of the diagnosis of the genus Mesophlebia...

Rethinking megafauna

Marcos Moleón, José Sánchez-Zapata, José Donázar, Eloy Revilla, Berta Martín-López, Cayetano Gutiérrez-Cánovas, Wayne Getz, Zebensui Morales-Reyes, Ahimsa Campos-Arceiz, Larry Crowder, Mauro Galetti, Manuela González-Suárez, Fengzhi He, Pedro Jordano, Rebecca Lewison, Robin Naidoo, Norman Owen-Smith, Nuria Selva, Jens-Christian Svenning, José Tella, Christiane Zarfl, Sonja Jähnig, Matt Hayward, Søren Faurby, Nuria García … & Klement Tochner
Concern for megafauna is increasing among scientists and non-scientists. Many studies have emphasized that megafauna play prominent ecological roles and provide important ecosystem services to humanity. But, what precisely are “megafauna”? Here we critically assess the concept of megafauna and propose a goal-oriented framework for megafaunal research. First, we review definitions of megafauna and analyze associated terminology in the scientific literature. Second, we conduct a survey among ecologists and paleontologists to assess the species traits...

Presents-absents of woody species on termite mounds and the savanna matrix in Africa

Justice Muvengwi & Ed Witkowski
Questions: Although the biogeography of plant communities has been well studied, mechanisms controlling plant community diversity are still poorly understood. Stochastic and deterministic processes are hotly debated as being key in structuring communities across taxa. Here we ask, to what extent are plant communities on termite mounds shaped by either stochastic or deterministic processes within and between regions on the African continent? Methods: We performed a meta-analysis on 23 studies that satisfied our selection criteria...

Data from: The role of browsers in maintaining the openness of savanna grazing lawns

Michael Voysey, Michelle Greve, Sally Archibald, William Bond, Carla Staver & Jason Donaldson
1. In savannas, ruminant herbivores can have divergent impacts on tree recruitment and resulting woody cover. Heavy grazing by cattle results in woody thickening, whereas intensive grazing by wildlife instead tends to be associated with lower woody cover. 2. To disentangle why woody cover is low in areas heavily grazed by wildlife, we tested (I) whether short-grass environments attract indigenous mammalian browsers; (II) whether preference for short grass decreases with browser body mass because of...

Datasets for phylogenetic analyses of Pavlomulina ranunculiformis

Ryoma Kamikawa, Masanobu Kawachi, Takuro Nakayama, Motoki Kayama, Mami Nomura, Hideaki Miyashita, Othman Bojo, Lesley Rhodes, Stuart Sym, Richard Pienaar, Ian Probert & Isao Inouye
Rapidly accumulating genetic data from environmental sequencing approaches have revealed an extraordinary level of unsuspected diversity within marine phytoplankton, which is responsible for around 50% of global net primary production. However, the phenotypic identity of many of the organisms distinguished by environmental DNA sequences remains unclear. The rappemonads are a plastid-bearing protistan lineage that to date has only been identified by environmental plastid 16S rRNA sequences. The phenotypic identity of this group, which does not...

Data from: Interspecific variation in post-disturbance growth responses of a savanna tree community and its implications for escaping the fire trap

Julienne E. NeSmith, Wayne Twine & Ricardo M. Holdo
Vegetation states in savannas are highly sensitive to tree growth rates, which determine whether individual trees can ‘escape’ periodic disturbances. Resprouting trees have lopsided shoot:root ratios and are often multi-stemmed, and these variables can modify post-disturbance growth rates and therefore the probability of escape. To date, few studies have systematically examined the implications of interspecific variation in these factors for escape. We conducted a two-year field experiment in lowveld savanna in South Africa and quantified...

Data from: Malar stripe size and prominence in peregrine falcons vary positively with solar radiation: Support for the solar glare hypothesis

Michelle Vrettos, Chevonne Reynolds & Arjun Amar
Many falcons (Falco spp.) exhibit a distinct dark plumage patch below the eye, termed the malar stripe. This stripe is hypothesised to reduce the amount of solar glare reflected into the eyes while foraging, thereby increasing hunting efficiency in bright conditions. Here, we use a novel, global-scale correlative approach to test this “solar glare hypothesis” in peregrine falcons (Falco peregrinus), the most widespread falcon species, using web-sourced photographs from across the species’ global range. We...

Data from: Fuelwood sustainability revisited: integrating size structure and resprouting into a spatially realistic fuelshed model

Wayne C. Twine & Ricardo M. Holdo
Much concern has been expressed about the sustainability of fuelwood harvesting in Africa. Most models predict that demand will outstrip supply within a few decades, resulting in severe deforestation. However, despite substantial impacts of harvesting on woody vegetation structure, the ‘fuelwood crisis’ predicted since the 1970s has not materialized. We propose that this is at least partially because regeneration through coppicing has been poorly accounted for in most models. We developed a local fuelwood model...

Data from: Revisiting the link between breeding effort and oxidative balance through field evaluation of two sympatric sibling insect species

Benjamin Rey, Pierre-François Pélisson, Marie-Claude Bel-Venner, Yann Voituron & Samuel Venner
The idea that oxidative stress could be a major force governing evolutionary trade-offs has recently been challenged by experimental approaches in laboratory conditions triggering extensive debates centered on theoretical and methodological issues. Here, we revisited the link between oxidative stress and reproduction by measuring multiple antioxidant and oxidative damages in wild-caught females of two sibling weevil species (Curculio elephas, C. glandium). The strength of our study arises from: (1) studied species are sympatric and exploit...

Data from: Evidence of large-scale range shift in the distribution of a Palaearctic migrant in Africa

Caroline Howes, Craig T. Symes & Patrik Byholm
Aim: Long-distance Palaearctic migrant birds are declining at a faster rate than short-distance migrant or resident species. This is often attributed to changes on their non-breeding grounds and along their migratory routes. The European Honey-buzzard (Pernis apivorus) is a scarce migrant in southern Africa that is declining globally. This study assessed the distribution and abundance of honey-buzzards in southern Africa over the past four decades and compared it to trends in the East African population...

Data from: A new species of burnetiid (Therapsida, Burnetiamorpha) from the early Wuchiapingian of South Africa and implications for the evolutionary ecology of the family Burnetiidae.

Michael O. Day, Roger M. H. Smith, Julien Benoit, Vincent Fernandez & Bruce S. Rubidge
Burnetiidae is a family of basal therapsids that is known from late Permian-aged (Lopingian) sequences from southern and eastern Africa and European Russia. Recent discoveries of related genera within the broader clade Burnetiamorpha have added to our understanding of morphological variation in the group but have eroded the list of characters defining the family Burnetiidae. We describe a new burnetiid taxon, Leucocephalus wewersi gen. et sp. nov., and argue that Burnetiidae can be defined by,...

Data from: An ambusher’s arsenal: chemical crypsis in the puff adder (Bitis arietans)

Ashadee Kay Miller, Bryan Maritz, Shannon McKay, Xavier Glaudas & Graham J. Alexander
Ambush foragers use a hunting strategy that places them at risk of predation by both visual and olfaction-oriented predators. Resulting selective pressures have driven the evolution of impressive visual crypsis in many ambushing species, and may have led to the development of chemical crypsis. However, unlike visual crypsis, few studies have attempted to demonstrate chemical crypsis. Field observations of puff adders (Bitis arietans) going undetected by several scent-orientated predator and prey species lead us to...

Grazing lawns and overgrazing in frequently grazed grass communities

Gareth Hempson, Kate Parr, Caroline Lehmann & Sally Archibald
Frequent grazing can establish high forage value grazing lawns supporting high grazer densities, but can also produce overgrazed grass communities with unpalatable or low grass basal cover, supporting few grazers. Attempts to create grazing lawns via concentrated grazing, with a goal to increase grazer numbers, are thus risky without knowing how environmental conditions influence the likelihood of each outcome. We collected grass species and trait data from 33 frequently grazed grass communities across eastern South...

Data from: Drought-induced starvation of aardvarks in the Kalahari: an indirect effect of climate change

Benjamin Rey, Andrea Fuller, Duncan Mitchell, Leith C.R. Meyer, Robyn S. Hetem & Leith C. R. Meyer
Aardvarks (Orycteropus afer) are elusive burrowing mammals, predominantly nocturnal and distributed widely throughout Africa except for arid deserts. Their survival may be threatened by climate change via direct and indirect effects of increasing heat and aridity. To measure their current physiological plasticity, we implanted biologgers into six adult aardvarks resident in the semi-arid Kalahari. Following a particularly dry and hot summer, five of the study aardvarks and 11 other aardvarks at the study site died....

Data from: Revisiting the measurement of anomie

Ali Teymoori, Jolanda Jetten, Brock Bastian, Amarina Ariyanto, Frédérique Autin, Nadia Ayub, Constantina Badea, Tomasz Besta, Fabrizio Butera, Rui Costa-Lopes, Lijuan Cui, Carole Fantini, Gillian Finchilesc, Lowell Gaertner, Mario Gollwitzer, Ángel Gómez, Roberto González, Ying Yi Hong, Dorthe Høj Jensen, Minoru Karasawa, Thomas Kessler, Olivier Klein, Marcus Lima, Tuuli Anna Mähönen, Laura Megevand … & Gillian Finchilescu
Sociologists coined the term "anomie" to describe societies that are characterized by disintegration and deregulation. Extending beyond conceptualizations of anomie that conflate the measurements of anomie as 'a state of society' and as a 'state of mind', we disentangle these conceptualizations and develop an analysis and measure of this phenomenon focusing on anomie as a perception of the 'state of society'. We propose that anomie encompasses two dimensions: a perceived breakdown in social fabric (i.e.,...

Data from: Delays and loss to follow up before treatment of drug-resistant TB following implementation of Xpert MTB/RIF in South Africa: a retrospective cohort study

Helen Cox, Lindy Dickson-Hall, Norbert Ndjeka, Anja Van't Hoog, Alison Grant, Frank Cobelens, Wendy Stevens, Mark Nicol & Anja Van’t Hoog
Background: South Africa has a large burden of rifampicin-resistant tuberculosis (RR-TB), with 18,734 patients diagnosed in 2014. The number of diagnosed patients has increased substantially with the introduction of the Xpert MTB/RIF test, used for TB diagnosis for all patients with presumptive TB. Routine aggregate data suggest a large treatment gap (pre-treatment loss to follow up) between the numbers of laboratory confirmed RR-TB patients and those reported to have started second-line treatment. We aimed to...

Data from: Functional attributes of savannah soils: contrasting effects of tree canopies and herbivores on bulk density, nutrients and moisture dynamics

Ricardo M. Holdo & Michelle C. Mack
1. Savannahs are highly heterogeneous tree-grass mixtures, and the structural variation imposed by a discontinuous canopy cover results in spatial variation in soil properties such as plant-available nutrients, temperature and soil moisture. Many savannahs are also dominated by large vertebrate herbivores, which impose a different suite of effects on soil properties related to consumption, excretion and physical disturbance. 2. In nutrient-poor, water-limited systems, variation in soil resource availability may play a fundamental role in structuring...

Data from: Herbivore size matters for productivity-richness relationships in African savannas

Deron E. Burkepile, Richard W. S. Fynn, Dave I. Thompson, Nathan P. Lemoine, Sally E. Koerner, Stephanie Eby, Nicole Hagenah, Kevin R. Wilcox, Scott L. Collins, Kevin P. Kirkman, Alan K. Knapp & Melinda D. Smith
1.Productivity and herbivory often interact to shape plant community composition and species richness with levels of production mediating the impact of herbivory. Yet, differences in herbivore traits such as size, feeding guild, and dietary requirements may result in different impacts of diverse herbivore guilds across productivity gradients. 2.We used size-selective herbivore exclosures to separate the effects of herbivory by larger herbivores, such as elephant, Burchell's zebra, and blue wildebeest from those of medium/smaller herbivores, such...

Data from: Accounting for differences in species frequency distributions when calculating beta diversity in the fossil record

Neil Brocklehurst, Michael O. Day & Jörg Fröbisch
1. Beta diversity is a measure of the taxonomic differentiation between habitats/localities within an assemblage, and is normally calculated as a set of pairwise taxonomic “distances” between the localities. 2. Due to the incomplete sampling, beta diversity estimates for fossil assemblages will always be higher than the true value. However, the difference between the observed and true distances will vary greatly depending on differences in the shape of the relative abundance distribution. 3. Using simulations,...

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