scholarly journals The evolution of quantitative sensitivity

2021 ◽  
Vol 377 (1844) ◽  
Author(s):  
Margaret A. H. Bryer ◽  
Sarah E. Koopman ◽  
Jessica F. Cantlon ◽  
Steven T. Piantadosi ◽  
Evan L. MacLean ◽  
...  
Keyword(s):  
Random Effect ◽  
Weber Fraction ◽  
Discrimination Performance ◽  
Quantity Discrimination ◽  
Mammal Species ◽  
Systems Neuroscience ◽  
Proximate Mechanisms ◽  
Neuron Density ◽  
Phylogenetic Regression ◽  
Species Specific

The ability to represent approximate quantities appears to be phylogenetically widespread, but the selective pressures and proximate mechanisms favouring this ability remain unknown. We analysed quantity discrimination data from 672 subjects across 33 bird and mammal species, using a novel Bayesian model that combined phylogenetic regression with a model of number psychophysics and random effect components. This allowed us to combine data from 49 studies and calculate the Weber fraction (a measure of quantity representation precision) for each species. We then examined which cognitive, socioecological and biological factors were related to variance in Weber fraction. We found contributions of phylogeny to quantity discrimination performance across taxa. Of the neural, socioecological and general cognitive factors we tested, cortical neuron density and domain-general cognition were the strongest predictors of Weber fraction, controlling for phylogeny. Our study is a new demonstration of evolutionary constraints on cognition, as well as of a relation between species-specific neuron density and a particular cognitive ability. This article is part of the theme issue ‘Systems neuroscience through the lens of evolutionary theory’.

Analog Numerical Representations in Rhesus Monkeys: Evidence for Parallel Processing

2004 ◽  
Vol 16 (5) ◽  
pp. 889-901 ◽  
Author(s):  
Andreas Nieder ◽  
Earl K. Miller
Keyword(s):  
Rhesus Monkeys ◽  
Neuronal Response ◽  
Weber Fraction ◽  
Discrimination Performance ◽  
Model Organisms ◽  
Response Latencies ◽  
Numerosity Discrimination ◽  
Numerical Information ◽  
Match To Sample ◽  
Numerical Representations

Monkeys have been introduced as model organisms to study neural correlates of numerical competence, but many of the behavioral characteristics of numerical judgments remain speculative. Thus, we analyzed the behavioral performance of two rhesus monkeys judging the numerosities 1 to 7 during a delayed match-to-sample task. The monkeys showed similar discrimination performance irrespective of the exact physical appearance of the stimuli, confirming that performance was based on numerical information. Performance declined smoothly with larger numerosities, and reached discrimination threshold at numerosity “4.” The nonverbal numerical representations in monkeys were based on analog magnitudes, object tracking process (“subitizing”) could not account for the findings because the continuum of small and large numbers shows a clear Weber fraction signature. The lack of additional scanning eye movements with increasing set sizes, together with indistinguishable neuronal response latencies for neurons with different preferred numerosities, argues for parallel encoding of numerical information. The slight but significant increase in reaction time with increasing numerosities can be explained by task difficulty and consequently time-consuming decision processes. The behavioral results are compared to single-cell recordings from the prefrontal cortex in the same subjects. Models for numerosity discrimination that may account for these results are discussed.

Response of wildlife to forest herbicide applications in northern coniferous ecosystems

1993 ◽  
Vol 23 (10) ◽  
pp. 2286-2299 ◽  
Author(s):  
R.A. Lautenschlager
Keyword(s):  
Small Mammal ◽  
Growing Season ◽  
Sampling Techniques ◽  
Mammal Species ◽  
Growing Seasons ◽  
Disturbed Areas ◽  
Herbicide Treatments ◽  
Species Specific ◽  
Small Mammal Species ◽  
Coniferous Ecosystems

Reviewed studies of the effects of forest herbicide applications on wildlife often lacked replication, pretreatment information, and (or) were conducted for only one or two growing seasons after treatment. Because of these problems, as well as the use of dissimilar sampling techniques, study conclusions have sometimes been contradictory. A review of eight studies of the effects of herbicide treatments on northern songbird populations in regenerating clearcuts indicates that total songbird populations are seldom reduced during the growing season after treatment. Densities of species that use early successional brushy, deciduous cover are sometimes reduced, while densities of species which commonly use more open areas, sometimes increase. A review of 14 studies of the effects of herbicide treatments on small mammals indicates that like songbirds, small mammal responses are species specific. Some species are unaffected, while some select and others avoid herbicide-treated areas. Only studies that use kill or removal trapping to study small mammal responses show density reductions associated with herbicide treatment. It seems that some small mammal species may be reluctant to venture into disturbed areas, although residents in those areas are apparently not affected by the disturbance. Fourteen relevant studies examined the effects of conifer release treatments on moose and deer foods and habitat use. Conifer release treatments reduce the availability of moose browse for as long as four growing seasons after treatment. The degree of reduction during the growing season after treatment varies with the herbicide and rate used. Deer use of treated areas remains unchanged or increases during the first growing season after treatment. Eight years after treating a naturally regenerated spruce–fir stand browse was three to seven times more abundant on treated than on control plots (depending on the chemical and rate used). Forage quality (nitrogen, ash, and moisture) of crop trees increased one growing season after the soil-active herbicide simazine was applied to control competition around outplanted 3-year-old balsam fir seedlings.

scholarly journals Numerosity representations in crows obey the Weber–Fechner law

2016 ◽  
Vol 283 (1827) ◽  
pp. 20160083 ◽  
Author(s):  
Helen M. Ditz ◽  
Andreas Nieder
Keyword(s):  
Weber Fraction ◽  
Discrimination Performance ◽  
Brain Structures ◽  
Number System ◽  
Number Line ◽  
Just Noticeable Difference ◽  
Match To Sample ◽  
Close Phylogenetic Relationship ◽  
The One ◽  
Numerical Representations

The ability to estimate number is widespread throughout the animal kingdom. Based on the relative close phylogenetic relationship (and thus equivalent brain structures), non-verbal numerical representations in human and non-human primates show almost identical behavioural signatures that obey the Weber–Fechner law. However, whether numerosity discriminations of vertebrates with a very different endbrain organization show the same behavioural signatures remains unknown. Therefore, we tested the numerical discrimination performance of two carrion crows ( Corvus corone ) to a broad range of numerosities from 1 to 30 in a delayed match-to-sample task similar to the one used previously with primates. The crows' discrimination was based on an analogue number system and showed the Weber-fraction signature (i.e. the ‘just noticeable difference’ between numerosity pairs increased in proportion to the numerical magnitudes). The detailed analysis of the performance indicates that numerosity representations in crows are scaled on a logarithmically compressed ‘number line’. Because the same psychophysical characteristics are found in primates, these findings suggest fundamentally similar number representations between primates and birds. This study helps to resolve a classical debate in psychophysics: the mental number line seems to be logarithmic rather than linear, and not just in primates, but across vertebrates.

scholarly journals Identifing priority ecoregions for rodent conservation at the genus level

Oryx ◽  
2001 ◽  
Vol 35 (2) ◽  
pp. 158-165 ◽  
Author(s):  
Giovanni Amori ◽  
Spartaco Gippoliti
Keyword(s):  
The Philippines ◽  
Conservation Priorities ◽  
Horn Of Africa ◽  
Mammal Species ◽  
Genus Level ◽  
Eastern Brazil ◽  
Western Sahel ◽  
High Species Richness ◽  
Species Specific ◽  
First Time

AbstractRodents account for 40 per cent of living mammal species. Nevertheless, despite an increased interest in biodiversity conservation and their high species richness, Rodentia are often neglected by conservationists. We attempt for the first time a world-wide evaluation of rodent conservation priorities at the genus level. Given the low popularity of the order, we considered it desirable to discuss identified priorities within the framework of established biodiversity priority areas of the world. Two families and 62 genera are recognized as threatened. Our analyses highlight the Philippines, New Guinea, Sulawesi, the Caribbean, China temperate forests and the Atlantic Forest of south-eastern Brazil as the most important (for their high number of genera) ‘threat-spots’ for rodent conservation. A few regions, mainly drylands, are singled out as important areas for rodent conservation but are not generally recognized in global biodiversity assessments. These are the remaining forests of Togo, extreme ‘western Sahel’, the Turanian and Mongolian-Manchurian steppes and the desert of the Horn of Africa. Resources for conservation must be allocated first to recognized threat spots and to those restricted-range genera which may depend on species-specific strategies for their survival.

scholarly journals Millennial-scale faunal record reveals differential resilience of European large mammals to human impacts across the Holocene

2016 ◽  
Vol 283 (1827) ◽  
pp. 20152152 ◽  
Author(s):  
Jennifer J. Crees ◽  
Chris Carbone ◽  
Robert S. Sommer ◽  
Norbert Benecke ◽  
Samuel T. Turvey
Keyword(s):  
Large Scale ◽  
Temporal Dynamics ◽  
Human Impacts ◽  
Biodiversity Loss ◽  
Mammal Species ◽  
The Holocene ◽  
Range Change ◽  
Spatio Temporal ◽  
Patterns And Processes ◽  
Species Specific

The use of short-term indicators for understanding patterns and processes of biodiversity loss can mask longer-term faunal responses to human pressures. We use an extensive database of approximately 18 700 mammalian zooarchaeological records for the last 11 700 years across Europe to reconstruct spatio-temporal dynamics of Holocene range change for 15 large-bodied mammal species. European mammals experienced protracted, non-congruent range losses, with significant declines starting in some species approximately 3000 years ago and continuing to the present, and with the timing, duration and magnitude of declines varying individually between species. Some European mammals became globally extinct during the Holocene, whereas others experienced limited or no significant range change. These findings demonstrate the relatively early onset of prehistoric human impacts on postglacial biodiversity, and mirror species-specific patterns of mammalian extinction during the Late Pleistocene. Herbivores experienced significantly greater declines than carnivores, revealing an important historical extinction filter that informs our understanding of relative resilience and vulnerability to human pressures for different taxa. We highlight the importance of large-scale, long-term datasets for understanding complex protracted extinction processes, although the dynamic pattern of progressive faunal depletion of European mammal assemblages across the Holocene challenges easy identification of ‘static’ past baselines to inform current-day environmental management and restoration.

scholarly journals Hunter-gatherers in context: Mammal community composition in a northern Tanzania landscape used by Hadza foragers and Datoga pastoralists

2020 ◽  
Author(s):  
Brian Wood ◽  
Riccardo S. Millar ◽  
Nicholas Wright ◽  
Joshua Baumgartner ◽  
Hannah Holmquist ◽  
...  
Keyword(s):  
Community Composition ◽  
Camera Traps ◽  
Sub Saharan Africa ◽  
Sampling Effort ◽  
Mammal Species ◽  
Hunter Gatherers ◽  
Wild Mammals ◽  
Northern Tanzania ◽  
Mammal Community ◽  
Species Specific

In many regions of sub Saharan Africa large mammals occur in human-dominated areas, yet their community composition and species-specific densities have rarely been described in areas occupied by traditional hunter-gatherers and pastoralists. Surveys of mammal populations in such areas provide important measures of biodiversity and provide ecological context for understanding hunting practices. Using a sampling grid centered on a Hadza hunter-gatherer camp and covering 36 km² of semi-arid savannah in northern Tanzania, we assessed mammals using camera traps (n = 19 stations) for c. 5 months (2,182 trap nights). In the study area (Tli’ika in the Hadza language), we recorded 36 wild mammal species, resembling a near complete mammal community. Rarefaction curves suggest that sampling effort was sufficient to capture mammal species richness. Species-specific densities were estimated using a random encounter model and site- and species’ body mass- specific estimates of the area sampled at each camera; confidence intervals were estimated using bootstrapping. Point estimates of densities varied by c. four orders of magnitude, from 0.003 ind./km² (African wild dog) to 27.5 ind./km² (Kirk’s dik dik). Densities of livestock (cattle, donkey, sheep and goat) were high, particularly when estimated using directly observed herd sizes. Cumulative biomass density of herbivorous livestock species exceeded that of all wild mammals by a factor of 3.3-38.7. We compare our study’s data to camera trap rates recorded in a fully protected area of northern Tanzania with similar precipitation (Lake Manyara National Park), revealing that abundance indices of most wildlife species in Tli’ika were much lower. We discuss how these data inform studies of Hadza hunting and models of hunter-gatherer foraging ecology and diet.

scholarly journals In situnovel environment assay reveals acoustic exploration as a repeatable behavioral response in migratory bats

2020 ◽  
Author(s):  
Theresa Schabacker ◽  
Oliver Lindecke ◽  
Sofia Rizzi ◽  
Lara Marggraf ◽  
Gunārs Pētersons ◽  
...  
Keyword(s):  
Behavioral Response ◽  
Mammal Species ◽  
Echolocation Call ◽  
Spatial Activity ◽  
Novel Environment ◽  
Exploration Behavior ◽  
Specific Variation ◽  
Species Specific

AbstractIntegrating information on species-specific sensory perception together with spatial activity provides a high-resolution understanding of how animals explore environments, yet frequently used exploration assays commonly ignore sensory acquisition as a measure for exploration. Echolocation is an active sensing system used by hundreds of mammal species, primarily bats. As echolocation call activity can be reliably quantified, bats present an excellent animal model to investigate intra-specific variation in environmental cue sampling. Here, we developed anin situroost-like novel environment assay for tree-cave roosting bats. We repeatedly tested 52 individuals of the migratory bat species,Pipistrellus nathusii, across 24 hours, to examine the role of echolocation when crawling through a maze-type arena and test for consistent intra-specific variation in sensory-based exploration. We reveal a strong correlation between echolocation call activity and spatial activity. Moreover, we show that during the exploration of the maze, individuals consistently differed in spatial activity as well as echolocation call activity given their spatial activity, a behavioral response we term ‘acoustic exploration’. Acoustic exploration was correlated with other exploratory behaviors, but not with emergence latency. We here present a relevant new measure for exploration behavior and provide evidence for consistent (short-term) intra-specific variation in the level at which wild bats collect information from a novel environment.

The long-term effects of logging for woodchips on small mammal populations

2009 ◽  
Vol 36 (8) ◽  
pp. 691 ◽  
Author(s):  
Daniel Lunney ◽  
Alison Matthews ◽  
Peggy Eby ◽  
Angela M. Penn
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Sustainable Forest Management ◽  
Long Term Effects ◽  
Mammal Species ◽  
North West ◽  
South Wales ◽  
Study Sites ◽  
Species Specific

Context. Long-term studies are internationally recognised as an essential component of achieving ecologically sustainable forest management with respect to fauna. Aims. This study aimed to assess longer-term responses of small mammals to logging by returning in 1998 to our 1980–83 study sites in south-eastern New South Wales, Australia. Methods. Three age-classes of forest were surveyed: unlogged; 18–19-year-old regrowth; and 26–34-year-old regrowth. Key results. Rattus fuscipes remained affected by logging, and there were significantly fewer R. fuscipes males in logged, north-west-facing sites than at other sites, although the effect was less pronounced in 1998 than in 1980–83. Antechinus agilis females were significantly less numerous in south-east-facing, unlogged forest. This was not expected from the 1980–83 results. Antechinus swainsonii, which had disappeared following a fire in 1980, had returned to the forest by 1998. A. swainsonii females showed a significant preference for south-east-facing slopes and this relationship was consistent between logged and unlogged forest. No members of Mus musculus or Sminthopsis leucopus, which were present in 1980–83, were caught in 1998. Conclusions. As in the 1980s study, the responses of small mammal species to logging history were varied and species specific. Implications. In our study area, we predict that sustained logging for woodchips will continue to deplete its populations of small mammals. This adds to the case for a more robust and sustained approach to researching and managing our forest fauna.

scholarly journals In situ novel environment assay reveals acoustic exploration as a repeatable behavioral response in migratory bats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Theresa Schabacker ◽  
Oliver Lindecke ◽  
Sofia Rizzi ◽  
Lara Marggraf ◽  
Gunārs Pētersons ◽  
...  
Keyword(s):  
Intraspecific Variation ◽  
Behavioral Response ◽  
Mammal Species ◽  
Echolocation Call ◽  
Spatial Activity ◽  
Novel Environment ◽  
Specific Variation ◽  
Species Specific

AbstractIntegrating information on species-specific sensory perception with spatial activity provides a high-resolution understanding of how animals explore environments, yet frequently used exploration assays commonly ignore sensory acquisition as a measure for exploration. Echolocation is an active sensing system used by hundreds of mammal species, primarily bats. As echolocation call activity can be reliably quantified, bats present an excellent model system to investigate intraspecific variation in environmental cue sampling. Here, we developed an in situ roost-like novel environment assay for tree-roosting bats. We repeatedly tested 52 individuals of the migratory bat species, Pipistrellus nathusii, across 24 h, to examine the role of echolocation when crawling through a maze-type arena and test for consistent intraspecific variation in sensory-based exploration. We reveal a strong correlation between echolocation call activity and spatial activity. Moreover, we show that during the exploration of the maze, individuals consistently differed in spatial activity as well as echolocation call activity, given their spatial activity, a behavioral response we term ’acoustic exploration’. Acoustic exploration was correlated with other exploratory behaviors, but not with emergence latency. We here present a relevant new measure for exploration behavior and provide evidence for consistent (short-term) intra-specific variation in the level at which wild bats collect information from a novel environment.

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