72 research outputs found
Are Historical Biogeographical Events Able to Promote Biological Diversification?
One of the goals of evolutionary biology is understanding how biological diversification change across spatial and temporal scales. Theoretically, it has been established that external (i.e., dispersals) and internal (i.e., origin of a key innovations) factors can modulate shifts in rates of species diversification. However, the role of historical events as trigger of species diversification rates have not been well understood in empirical studies. I reviewed the literature linking historical biogeographic events and species diversification in many groups. Many of studies conclude that dispersals can be associated with exceptional changes in species diversification rates in insular and mainland areas. I discuss the limitations of some approaches used to discover the link between historical biogeography and macroevolution. I propose some predictions under biogeographic scenarios to gain understanding in how historical events promote biological diversification. I suggest that future studies linking biogeography and macroevolution should incorporate ecologically-relevant traits to discern the mechanisms underlying these historical associations. Although new developments in phylogenetic comparative methods have been done, still is necessary more traditional field-based ecological and evolutionary research. The link between biogeography and diversification still remains narrative and a comprehensive approach is necessary to establish how diversification was triggered by historical events
Interaction with touchscreen smartphones in patientswith essential tremor and healthy individuals.
tremorAbstractIntroduction: Smartphone use in biomedical research is becoming more prevalent in differ-ent clinical settings. We performed a pilot study to obtain information on smartphone use bypatients with essential tremor (ET) and healthy controls, with a view to determining whetherperformance of touchscreen tasks is different between these groups and describing touchscreeninteraction factors.Method: A total of 31 patients with ET and 40 sex- and age-matched healthy controls com-pleted a descriptive questionnaire about the use of smartphones. Participants subsequentlyinteracted with an under-development Android application, and performed 4 tests evaluatingtypical touchscreen interaction gestures; each test was performed 5 times.Result: The type of smartphone use and touchscreen interaction were not significantly differ-ent between patients and controls. Age and frequency of smartphone use are key factors intouchscreen interaction.Conclusion: Our results support the use of smartphone touchscreens for research into ET,although further studies are required.pre-print1030 K
Climatic niche attributes and diversification in Anolis lizards
Aim
The aim of this study was to test the link between climatic niche dynamics and species diversification in Anolis on islands and on the mainland. We tested the hypotheses that lineages in warmer climates and with narrow climate niches diversified more than lineages in cold climates and with broad climate niches. We also tested the hypothesis that species-rich clades exhibit greater niche diversity than species-poor clades.
Location
Neotropics.
Methods
We collated occurrence records for 328 Anolis species to estimate niche breadth, niche position and occupied niche space (as a proxy for niche diversity). We compared niche breadth between insular and mainland Anolis species and among Anolis clades, controlling for the potential confounding effect of range size. Using two approaches (clade-based and QuaSSE) we explored the association between niche metrics and diversification rates in Anolis lizards.
Results
We found that Caribbean Anolis had a narrower niche breadth and niche space occupation compared to mainland anoles after controlling for range size differences. There was a significant association between niche traits (mean niche position and niche breadth) and diversification in anoles. Anole lineages with narrow niche breadths and that occupy warmer areas exhibited higher speciation rates than those with broader niche breadths and that occupy cold areas. Similarly, clades with higher total diversification exhibit more niche diversity than clades with lower total diversification.
Main conclusions
Climatic niche attributes play a role in anole diversification with some differences between mainland and insular anole lineages. Climatic niche differences between regions and clades likely are related to differences in niche evolutionary rates. This also suggests that climate plays a strong role in shaping species richness between and within mainland and islands
Patterns and drivers of climatic niche dynamics during biological invasions of island-endemic amphibians, reptiles, and birds
Shifts between native and alien climatic niches pose a major challenge for predicting biological invasions. This is particularly true for insular species because geophysical barriers could constrain the realization of their fundamental niches, which may lead to underestimates of their invasion potential. To investigate this idea, we estimated the frequency of shifts between native and alien climatic niches and the magnitude of climatic mismatches using 80,148 alien occurrences of 46 endemic insular amphibian, reptile, and bird species. Then, we assessed the influence of nine potential predictors on climatic mismatches across taxa, based on species' characteristics, native range physical characteristics, and alien range properties. We found that climatic mismatch is common during invasions of endemic insular birds and reptiles: 78.3% and 55.1% of their respective alien records occurred outside of the environmental space of species' native climatic niche. In comparison, climatic mismatch was evident for only 16.2% of the amphibian invasions analyzed. Several predictors significantly explained climatic mismatch, and these varied among taxonomic groups. For amphibians, only native range size was associated with climatic mismatch. For reptiles, the magnitude of climatic mismatch was higher for species with narrow native altitudinal ranges, occurring in topographically complex or less remote islands, as well as for species with larger distances between their native and alien ranges. For birds, climatic mismatch was significantly larger for invasions on continents with higher phylogenetic diversity of the recipient community, and when the invader was more evolutionarily distinct. Our findings highlight that apparently common niche shifts of insular species may jeopardize our ability to forecast their potential invasions using correlative methods based on climatic variables. Also, we show which factors provide additional insights on the actual invasion potential of insular endemic amphibians, reptiles, and birds
AIRCC-Clim: A user-friendly tool for generating regional probabilistic climate change scenarios and risk measures
Complex physical models are the most advanced tools available for producing realistic simulations of the climate system. However, such levels of realism imply high computational cost and restrictions on their use for policymaking and risk assessment. Two central characteristics of climate change are uncertainty and that it is a dynamic problem in which international actions can significantly alter climate projections and information needs, including partial and full compliance of global climate goals. Here we present AIRCC-Clim, a simple climate model emulator that produces regional probabilistic climate change projections of monthly and annual temperature and precipitation, as well as risk measures, based both on standard and user-defined emissions scenarios for six greenhouse gases. AIRCC-Clim emulates 37 atm-ocean coupled general circulation models with low computational and technical requirements for the user. This standalone, user-friendly software is designed for a variety of applications including impact assessments, climate policy evaluation and integrated assessment modelling
Assessment of Tremor Severity in Patients with Essential Tremor Using Smartwatches
[Abstract] This paper presents a classification model for the automatic quantification of tremor severity in patients with essential tremor (ET). The system is based on the signals measured by two commercial smartwatches that the patients wear on their wrist and ankle. The smartwatches register acceleration and angular velocity in these body segments. A set of nine tremor features were used to train the classification algorithm. The proposed algorithm is based on a C4.5 decision tree classifier. It is able to assess rest and kinetic (postural or action) tremor. The method was evaluated using data collected from thirty-four patients with ET. The algorithm classifies the severity of tremor in five levels 0-4 corresponding to those in the Fahn-Tolosa-Marin tremor rating scale with a 94% accuracy. The method can be implemented in a networked platform for the remote monitoring and assessment of movement disorders such as ET or Parkinson’s disease.Ministerio de Economía, Industria u Competitividad; RTC-2015-3967-1Ministerio de Economía, Industria u Competitividad; DPI2015-68664-C4-1-RMinisterio de Economía, Industria u Competitividad; RTC-2015-4327-
Evaluating Risk and Possible Adaptations to Climate Change Under a Socio-Ecological System Approach
Evidence suggests that climate change could drastically reduce Mexico's agricultural productivity with severe socio-ecological consequences. Population growth and the increasing demand of resources will exacerbate these impacts. Focusing on rainfed maize production, we evaluate the socio-ecological risk that municipalities currently face and how climate change could modify it. Municipalities were classified based on their biophysical and socioeconomic traits like temperature, precipitation, population, gross domestic product, marginalization, and agricultural subsidies. The study identifies municipalities that would face higher risk under climate change conditions, and it evaluates whether increases in agricultural subsidies could be effective for reducing the farmers' future risk. Our results show that during the 2010's, 36.8% of the municipalities and 15% of the population were at very high and high risk, respectively. By 2070, under a high-warming scenario these figures increase to 56.5 and 18.5%. We find that a generalized augment in agricultural subsidies is not enough to compensate for the effects of climate change on the socio-ecological risk of rainfed maize producers. We suggest that transformative adaptation is required for managing the agricultural risk that socio-ecological systems experience under climate change conditions. Such adaptation strategies should include poverty alleviation, promotion of resistant and native varieties of crops, capacity building to improve management and water use, sustainable technification, and soil restoration
A new cryptic species of Anolis lizard from northwestern South America (Iguanidae, Dactyloinae)
A new species of Anolis lizard from the Andean slopes of southwestern Colombia and northwestern Ecuador, from between 1187 and 2353 m in elevation, is described. The new species can be distinguished from other Anolis in squamation, cranial osteology, hemipenial morphology, and nuclear and mitochondrial DNA. The new species is sister to Anolis aequatorialis, and it is suggested that previous records of A. aequatorialis in Colombia correspond to the new species described herein
Climatic and evolutionary factors shaping geographical gradients of species richness in Anolis lizards
Understanding the climatic and historical factors shaping species richness is a major goal of ecology and biogeography. Consensus on how climate affects species richness is still lacking, but four potential and non-exclusive explanations have emerged: water-energy, where diversity is determined by precipitation and/or temperature; seasonality, where diversity is determined by seasonal variation in climate; heterogeneity, where diversity is determined by spatial variability in climate; and historical climatic stability, where diversity is determined by changes in climate through evolutionary time. Climate–richness relationships are also mediated by historical processes such as phylogenetic niche conservatism and lineage diversification across regions. We evaluated the effect of climate on species richness gradients of Anolis lizards and tested the role of phylogenetic niche conservatism (PNC) and regional diversification (RD) in the origin and maintenance of climate-richness relationships. Climate had a strong non-stationary relationship with species richness with strong shared effects among several climate axes. Regional differences in climate–richness relationships suggest different assembly processes between regions. However, we did not find evidence for a role of evolutionary factors such as PNC or RD underlying these relationships. We suggest that evolutionary processes affecting climate-richness relationships in Anolis likely were obscured by high dispersal rates between regions
Climatic and evolutionary factors shaping geographical gradients of species richness in Anolis lizards
Understanding the climatic and historical factors shaping species richness is a major goal of ecology and biogeography. Consensus on how climate affects species richness is still lacking, but four potential and non-exclusive explanations have emerged: water-energy, where diversity is determined by precipitation and/or temperature; seasonality, where diversity is determined by seasonal variation in climate; heterogeneity, where diversity is determined by spatial variability in climate; and historical climatic stability, where diversity is determined by changes in climate through evolutionary time. Climate–richness relationships are also mediated by historical processes such as phylogenetic niche conservatism and lineage diversification across regions. We evaluated the effect of climate on species richness gradients of Anolis lizards and tested the role of phylogenetic niche conservatism (PNC) and regional diversification (RD) in the origin and maintenance of climate-richness relationships. Climate had a strong non-stationary relationship with species richness with strong shared effects among several climate axes. Regional differences in climate–richness relationships suggest different assembly processes between regions. However, we did not find evidence for a role of evolutionary factors such as PNC or RD underlying these relationships. We suggest that evolutionary processes affecting climate-richness relationships in Anolis likely were obscured by high dispersal rates between regions
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