Niche position and niche breadth effects on population abundances: A case study of New World Warblers (Parulidae).

Species abundance patterns are influenced by a myriad of factors, including habitat availability and ecological niche characteristics. However, the evidence concerning the specific impact factors such as niche position and niche breadth on mean and maximum abundances in vertebrates at a broad geographical scale remains inconclusive. In this study, we investigated the influence of niche position and breadth on the abundance of 47 species of birds belonging to the Parulidae family, commonly known as New World Warblers. We obtained data on abundance and presence records spanning the reproductive distribution of these species and employed the outlying mean index analysis to calculate niche position and niche breadth. We assessed the relationship between abundance metrics and niche descriptors using phylogenetic regressions to account for the non-independence resulting from phylogenetic ancestry. Initially, we developed individual models for each predictor and subsequently formulated a multi-predictor model encompassing niche position, niche breadth, and their interaction. Our findings revealed a negative relationship between niche position and both mean and maximum abundance, while niche breadth exhibited a positive relationship with these niche characteristics. Notably, the results of the multi-predictor models indicated that niche position exerted the most substantial influence on both mean and maximum abundance. Additionally, the interaction between niche position and niche breadth had the most positive and significant contribution to mean population abundance. This study underscores the need for future research in other vertebrates to delve into the mechanisms underlying these patterns. Such endeavors will not only enhance our understanding of ecological dynamics but also equip us with predictive capabilities to anticipate population responses to environmental changes effectively.

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.

Seasonal droughts during the Miocene drove the evolution of Capparaceae towards Neotropical seasonally dry forests / Las sequías estacionales del Mioceno impulsaron la evolución de Capparaceae hacia los bosques neotropicales estacionalmente secos

Abstract Introduction: Neotropical seasonally dry forest (NSDF) climatic constraints increased endemism, and phylogenetic niche conservatism in species that are restricted to this biome. NSDF have a large number of endemic Capparaceae taxa, but it is unknown if phylogenetic niche conservatism has played a role in this pattern. Objective: We carried out an evolutionary analysis of the climatic niche of neotropical species of Capparaceae to identify whether the climatic constraints of NSDF have played a major role throughout the family's evolutionary history. Methods: Using three chloroplastic (ndhF, matK, rbcL) and one ribosomal (rsp3) DNA sequences, we proposed a date phylogeny to reconstruct the evolutionary climatic niche dynamics of 24 Neotropical species of Capparaceae. We tested the relationship between niche dissimilarity and phylogenetic distance between species using the Mantel test. Likewise, we used a set of phylogenetic comparative methods (PGLS) on the phylogeny of Capparaceae to reconstruct the main evolutionary historic events in their niche. Results: Capparaceae originated in humid regions and subsequently, convergent evolution occurred towards humid and dry forest during the aridification phases of the Middle Miocene (16-11 Mya). However, adaptation towards drought stress was reflected only during the precipitation of the coldest quarter, where we found phylogenetic signal (Pagel λ) for gradual evolution and, therefore, evidence of phylogenetic niche conservatism. We found convergent species-specific adaptations to both drought stress and rainfall during the Miocene, suggesting a non-phylogenetic structure in most climatic variables. Conclusions: Our study shows how the Miocene climate may have influenced the Capparaceae speciation toward driest environments. Further, highlights the complexity of climatic niche dynamics in this family, and therefore more detailed analyses are necessary in order to better understand the NSDF climatic constrictions affected the evolution of Capparaceae.

Resumen Introducción: Las limitaciones climáticas del bosque neotropical estacionalmente seco (NSDF) produjeron endemismo y conservadurismo filogenético del nicho en especies restringidas a este bosque. En las Caparáceas neotropicales se ha encontrado endemismo en los NSDF, pero se desconoce si el conservadurismo de nicho filogenético ha influido en su evolución. Objetivos: Se llevó a cabo un análisis evolutivo del nicho climático de las especies neotropicales de Capparaceae para evaluar si las limitaciones climáticas del bosque neotropical estacionalmente seco (NSDF) han jugado un papel importante a lo largo de la historia evolutiva de la familia. Métodos: Usando tres secuencias de ADN cloroplastico (ndhF, matK, rbcL) y una ribosomal (rsp3) se propuso una filogenia datada para reconstruir la dinámica evolutiva del nicho climático de 24 especies Neotropicales de Capparaceae. Utilizando la prueba de Mantel, se realizaron análisis para establecer si hay diferencia de nicho y la distancia filogenética entre especies. Asimismo, se emplearon un conjunto de métodos comparativos filogenéticos sobre la filogenia de la familia para reconstruir los principales eventos históricos evolutivos en su nicho. Resultados: Capparaceae se originó en regiones húmedas y posteriormente se dio una evolución convergente hacia bosque húmedo y seco durante las fases de aridificación del Mioceno Medio (16-11 Ma). Sin embargo, la adaptación al estrés por sequía se reflejó solo en la precipitación del cuarto más frío del año, donde se evidencio señal filogenética, evolución gradual y, por lo tanto, evidencia de conservadurismo de nicho filogenético. También se hallaron especies con adaptaciones convergentes específicas tanto al estrés por sequía como a las lluvias durante el Mioceno, sugiriendo la carencia de estructura filogenética en la mayoría de las variables climáticas. Conclusiones: Este estudio muestra cómo el clima del Mioceno pudo haber influenciado la especiación de Capparaceae hacia ambientes mas secos. Además, la compleja dinámica del nicho climático en esta familia y, por lo tanto, la necesidad de realizar análisis más detallados para comprender mejor como las constricciones climáticas del NSDF afectaron la evolución de Capparaceae.

Toward New Epidemiological Landscapes of Trypanosoma cruzi (Kinetoplastida, Trypanosomatidae) Transmission under Future Human-Modified Land Cover and Climatic Change in Mexico.

Chagas disease, caused by the protozoa Trypanosoma cruzi, is an important yet neglected disease that represents a severe public health problem in the Americas. Although the alteration of natural habitats and climate change can favor the establishment of new transmission cycles for T. cruzi, the compound effect of human-modified landscapes and current climate change on the transmission dynamics of T. cruzi has until now received little attention. A better understanding of the relationship between these factors and T. cruzi presence is an important step towards finding ways to mitigate the future impact of this disease on human communities. Here, we assess how wild and domestic cycles of T. cruzi transmission are related to human-modified landscapes and climate conditions (LUCC-CC). Using a Bayesian datamining framework, we measured the correlations among the presence of T. cruzi transmission cycles (sylvatic, rural, and urban) and historical land use, land cover, and climate for the period 1985 to 2012. We then estimated the potential range changes of T. cruzi transmission cycles under future land-use and -cover change and climate change scenarios for 2050 and 2070 time-horizons, with respect to "green" (RCP 2.6), "business-as-usual" (RCP 4.5), and "worst-case" (RCP 8.5) scenarios, and four general circulation models. Our results show how sylvatic and domestic transmission cycles could have historically interacted through the potential exchange of wild triatomines (insect vectors of T. cruzi) and mammals carrying T. cruzi, due to the proximity of human settlements (urban and rural) to natural habitats. However, T. cruzi transmission cycles in recent times (i.e., 2011) have undergone a domiciliation process where several triatomines have colonized and adapted to human dwellings and domestic species (e.g., dogs and cats) that can be the main blood sources for these triatomines. Accordingly, Chagas disease could become an emerging health problem in urban areas. Projecting potential future range shifts of T. cruzi transmission cycles under LUCC-CC scenarios we found for RCP 2.6 no expansion of favourable conditions for the presence of T. cruzi transmission cycles. However, for RCP 4.5 and 8.5, a significant range expansion of T. cruzi could be expected. We conclude that if sustainable goals are reached by appropriate changes in socio-economic and development policies we can expect no increase in suitable habitats for T. cruzi transmission cycles.

Amphibian Speciation Rates Support a General Role of Mountains as Biodiversity Pumps.

AbstractContinental mountain areas cover <15% of global land surface, yet these regions concentrate >80% of global terrestrial diversity. One prominent hypothesis to explain this pattern proposes that high mountain diversities could be explained by higher diversification rates in regions of high topographic complexity (HTC). While high speciation in mountains has been detected for particular clades and regions, the global extent to which lineages experience faster speciation in mountains remains unknown. Here we addressed this issue using amphibians as a model system (>7,000 species), and we found that families showing high speciation rates contain a high proportion of species distributed in mountains. Moreover, we found that lineages inhabiting areas of HTC speciate faster than lineages occupying areas that are topographically less complex. When comparing across regions, we identified the same pattern in five biogeographical realms where higher speciation rates are associated with higher levels of complex topography. Low-magnitude differences in speciation rates between some low and high complex topographies suggest that high mountain diversity is also affected by low extinction and/or high colonization rates. Nevertheless, our results bolster the importance of mountains as engines of speciation at different geographical scales and highlight their importance for the conservation of global biodiversity.

Ex-post correction of pacemaker mode switch episodes in undersensed atrial fibrillation.

BACKGROUND: Information about short Atrial Fibrillation (AF) episodes can be gathered from the diagnostic records of cardiac implantable electronic devices (CIEDs). CIEDs are not accurate when detecting short arrhythmia episodes. The correlation between mode switching events and AF episodes is significant for long events but prone to errors for short episodes. METHODS: Expectation-maximization algorithms are used to estimate the parameters of a mathematical model from a list of AF episodes produced by the CIED. The durations of some of the episodes may be missing. Abnormal mode changes are detected and short episodes are joined into longer events when appropriate. The proposed method does not require that the sensitivity parameters of the device are altered. Post-processing of the data is limited to the detection of false negatives, thus paroxysmal arrhythmia diagnostic evaluations are safer. RESULTS: A three year-long study was carried out with patients with dual-chamber pacemakers (PM) at the Hospital Universitario Central de Asturias (Spain) between 2012 and 2015. The number of patients in which the proposed algorithm altered the final histogram was 40 out of 76. On average, the algorithm removes 2.79% of episodes shorter than 1 min in length and finds that 1% of the previously unaccounted episodes are longer than 30 min, of which 16% are longer than 24 h. CONCLUSION: The method is stable and guarantees that long arrhythmia episodes are never eliminated, and at the same time it is the most similar to the human expert in finding new long episodes.

Synergistic impacts of global warming and thermohaline circulation collapse on amphibians.

Impacts on ecosystems and biodiversity are a prominent area of research in climate change. However, little is known about the effects of abrupt climate change and climate catastrophes on them. The probability of occurrence of such events is largely unknown but the associated risks could be large enough to influence global climate policy. Amphibians are indicators of ecosystems' health and particularly sensitive to novel climate conditions. Using state-of-the-art climate model simulations, we present a global assessment of the effects of unabated global warming and a collapse of the Atlantic meridional overturning circulation (AMOC) on the distribution of 2509 amphibian species across six biogeographical realms and extinction risk categories. Global warming impacts are severe and strongly enhanced by additional and substantial AMOC weakening, showing tipping point behavior for many amphibian species. Further declines in climatically suitable areas are projected across multiple clades, and biogeographical regions. Species loss in regional assemblages is extensive across regions, with Neotropical, Nearctic and Palearctic regions being most affected. Results underline the need to expand existing knowledge about the consequences of climate catastrophes on human and natural systems to properly assess the risks of unabated warming and the benefits of active mitigation strategies.

Hurricane effects on Neotropical lizards span geographic and phylogenetic scales.

Extreme climate events such as droughts, cold snaps, and hurricanes can be powerful agents of natural selection, producing acute selective pressures very different from the everyday pressures acting on organisms. However, it remains unknown whether these infrequent but severe disruptions are quickly erased by quotidian selective forces, or whether they have the potential to durably shape biodiversity patterns across regions and clades. Here, we show that hurricanes have enduring evolutionary impacts on the morphology of anoles, a diverse Neotropical lizard clade. We first demonstrate a transgenerational effect of extreme selection on toepad area for two populations struck by hurricanes in 2017. Given this short-term effect of hurricanes, we then asked whether populations and species that more frequently experienced hurricanes have larger toepads. Using 70 y of historical hurricane data, we demonstrate that, indeed, toepad area positively correlates with hurricane activity for both 12 island populations of Anolis sagrei and 188 Anolis species throughout the Neotropics. Extreme climate events are intensifying due to climate change and may represent overlooked drivers of biogeographic and large-scale biodiversity patterns.

What drives genetic and phenotypic divergence in the Red-crowned Ant tanager (Habia rubica, Aves: Cardinalidae), a polytypic species?

AIM: The effects of geographic and environmental variables on patterns of genetic and phenotypic differentiation have been thoroughly studied. Ecological speciation involves reproductive isolation due to divergent natural selection that can result in a positive correlation between genetic divergence and adaptive phenotypic divergence (isolation by adaptation, IBA). If the phenotypic target of selection is unknown or not easily measured, environmental variation can be used as a proxy, expecting positive correlation between genetic and environmental distances, independent of geographic distances (isolation by environment, IBE). The null model is that the amount of gene flow between populations decreases as the geographic distance between them increases, and genetic divergence is due simply to the neutral effects of genetic drift (isolation by distance, IBD). However, since phenotypic differentiation in natural populations may be autocorrelated with geographic distance, it is often difficult to distinguish IBA from the neutral expectation of IBD. In this work, we test hypotheses of IBA, IBE, and IBD in the Red-crowned Ant tanager (Habia rubica). LOCATION: Mesoamerica (Mexico-Central America) and South America. TAXON: Habia rubica (Aves: Cardinalidae). METHODS: We compiled genetic data, coloration, and morphometric data from specimens from collections in Mexico and the United States. We used the Multiple Matrix Regression with Randomization (MMRR) approach to evaluate the influence of geographic and environmental distances on genetic and phenotypic differentiation of H. rubica at both phylogroup and population levels. RESULTS: Our results provide strong evidence that geographic distance is the main driver of genetic variation in H. rubica. We did not find evidence that climate variation is driving population differentiation in this species across a widespread geographic region. MAIN CONCLUSIONS: Our data point to geographic isolation as the main factor structuring genetic variation within populations of H. rubica and suggest that climate is not playing a major role in genetic differentiation within this species.

Solitary ecology as a phenomenon extending beyond insular systems: exaptive evolution in Anolis lizards.

The mechanisms driving phenotypic evolution have been of interest to biologists since Darwin. Ecological release-wherein adaptive evolution occurs following relaxation of constraining selective pressures-and environmental filtering-wherein exaptive traits allow colonization of a new area-have been studied in several insular cases. Anolis lizards, which may exist in solitude or sympatry with multiple congeners, are an excellent system for evaluating whether ecological release and environmental filtering are associated with phenotypic shifts across phylogenetic and geographical scales. Insular solitary Anolis exhibit phenotypic differentiation in body size and sexual size dimorphism-SSD-through exaptive and adaptive evolution, respectively. But, the generality of these effects has not yet been addressed. Here, we analyse the evolution of body size and SSD relative to sympatry in mainland Anolis. We found that mainland species co-occurring with few congeners exhibit uniform body size and greater SSD relative to other random mainland assemblages, consistent with the insular solitary pattern. The locations of evolutionary shifts for both traits do not coincide with evolutionary transitions to decreased levels of sympatry. These results are consistent with exaptive environmental filtering but not adaptive ecological release. Future studies should be conducted at local scales to evaluate the role of these factors in the evolution of solitary existence in mainland and island species.

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 Anolisaequatorialis, and it is suggested that previous records of A.aequatorialis in Colombia correspond to the new species described herein.

ResumenDescribimos una nueva especie de Anolis de las estribaciones de los Andes del suroccidente de Colombia y noroccidente de Ecuador, entre los 1187 y 2353 metros de elevación. La nueva especie puede ser distinguida de otros Anolis por caracteres de escamación, osteología craneal, morfología hemipenial, y ADN nuclear y mitocondrial. La nueva especie es hermana de A.aequatorialis, por lo que sugerimos que los registros previos de A.aequatorialis en Colombia corresponden a la nueva especie descrita en este artículo.

Comparative Evolution of an Archetypal Adaptive Radiation: Innovation and Opportunity in Anolis Lizards.

Adaptive radiation is a widely recognized pattern of evolution wherein substantial phenotypic change accompanies rapid speciation. Adaptive radiation may be triggered by environmental opportunities resulting from dispersal to new areas or via the evolution of traits, called key innovations, that allow for invasion of new niches. Species sampling is a known source of bias in many comparative analyses, yet classic adaptive radiations have not been studied comparatively with comprehensively sampled phylogenies. In this study, we use unprecedented comprehensive phylogenetic sampling of Anolis lizard species to examine comparative evolution in this well-studied adaptive radiation. We compare adaptive radiation models within Anolis and in the Anolis clade and a potential sister lineage, the Corytophanidae. We find evidence for island (i.e., opportunity) effects and no evidence for trait (i.e., key innovation) effects causing accelerated body size evolution within Anolis. However, island effects are scale dependent: when Anolis and Corytophanidae are analyzed together, no island effect is evident. We find no evidence for an island effect on speciation rate and tenuous evidence for greater speciation rate due to trait effects. These results suggest the need for precision in treatments of classic adaptive radiations such as Anolis and further refinement of the concept of adaptive radiation.

A Phylogenetic, Biogeographic, and Taxonomic study of all Extant Species of Anolis (Squamata; Iguanidae).

Anolis lizards (anoles) are textbook study organisms in evolution and ecology. Although several topics in evolutionary biology have been elucidated by the study of anoles, progress in some areas has been hampered by limited phylogenetic information on this group. Here, we present a phylogenetic analysis of all 379 extant species of Anolis, with new phylogenetic data for 139 species including new DNA data for 101 species. We use the resulting estimates as a basis for defining anole clade names under the principles of phylogenetic nomenclature and to examine the biogeographic history of anoles. Our new taxonomic treatment achieves the supposed advantages of recent subdivisions of anoles that employed ranked Linnaean-based nomenclature while avoiding the pitfalls of those approaches regarding artificial constraints imposed by ranks. Our biogeographic analyses demonstrate complexity in the dispersal history of anoles, including multiple crossings of the Isthmus of Panama, two invasions of the Caribbean, single invasions to Jamaica and Cuba, and a single evolutionary dispersal from the Caribbean to the mainland that resulted in substantial anole diversity. Our comprehensive phylogenetic estimate of anoles should prove useful for rigorous testing of many comparative evolutionary hypotheses. [Anoles; biogeography; lizards; Neotropics; phylogeny; taxonomy].

Morphometric analysis of the Rio Apaporis Caiman (Reptilia, Crocodylia, Alligatoridae).

Caiman crocodilus apaporiensis has been considered by several authors as an extreme of morphological variation within the Caiman crocodilus complex. Here, we evaluate its position in the Caiman crocodilus complex morphospace using morphological traits from head shape. We examined the holotype and seventeen paratypes of Caiman crocodilus apaporiensis Medem 1955 deposited at the Field Museum of Natural History. We performed multivariate morphometric analyses: principal component analysis (PCA) and discriminant function analysis (DFA), based on 21 cranial traits of of C. c. apaporiensis, C. yacare and the C. crocodilus complex (C. c. chiapasius, C. c. fuscus andC. c. crocodilus). We find a notable separation of C.c. apaporiensis from C. yacare and C. crocodilus complex in the morphospace. We suggest that geographic isolation might have driven this morphological separation from the C. crocodilus complex, but further analysis are necessary to confirm whether these differences are related with genetic differentiation within the complex. In addition, we suggest that environmental heterogeneity might drive the evolution of independent lineages within the C. crocodilus complex.

A new green anole lizard of the "Dactyloa" clade (Squamata: Dactyloidae) from the Magdalena river valley of Colombia .

We describe a new species of Anolis from the Magdalena river valley in Colombia. The new species is morphologically similar to Anolis ibanezi and A. chocorum, but differs in body and dewlap color, and head scalation. We performed an exploratory multivariate analysis based on 15 morphological characteristics of the new species and A chocorum and found that differences between both species are mainly associated with head dimensions. A phylogenetic analysis based on morphological characters suggests that the new species is nested within the "Dactyloa" clade of Anolis. Finally, we discuss phylogenetic relationships and biogeographical affinities based in its distribution. 

Finite element approximation of a population spatial adaptation model.

In [18], Sighesada, Kawasaki and Teramoto presented a system of partial differential equations for modeling spatial segregation of interacting species. Apart from competitive Lotka-Volterra (reaction) and population pressure (cross-diffusion) terms, a convective term modeling the populations attraction to more favorable environmental regions was included. In this article, we study numerically a modification of their convective term to take account for the notion of spatial adaptation of populations. After describing the model, in which a time non-local drift term is considered, we propose a numerical discretization in terms of a mass-preserving time semi-implicit finite element method. Finally, we provied the results of some biologically inspired numerical experiments showing qualitative differences between the original model of [18] and the model proposed in this article.

¿Puede sustituir la prueba de brucellacapt® a la prueba de coombs en el diagnóstico de la brucelosis humana? / Brucellacapt® test to replace Coombs test in the serological diagnosis of human brucellosis?

FUNDAMENTOS. En este trabajo hemos estudiado la capacidad de la prueba Brucellacapt® para sustituir a la prueba de Coombs en el diagnóstico de la brucelosis humana. MÉTODOS. Se estudiaron sueros de 66 pacientes de brucelosis. Los pacientes se dividieron en dos grupos: grupo 1 (42 pacientes primoinfectados) y grupo 2 (24 pacientes con antecedentes de la enfermedad). Como población complementaria se utilizaron 100 sueros de individuos de población general para el grupo 1, y 28 sueros de individuos sanos con antecedentes de brucelosis para el grupo 2. A todos los sueros se les practicaron las pruebas de Coombs y Brucellacapt®, y se estudió el rendimiento diagnóstico de ambas en los dos grupos mediante la elaboración de curvas ROC (receiver operating characteristic).A 397 sueros de 66 pacientes con brucelosis se les practicaron las pruebas de Coombs y Brucellacapt® y los resultados obtenidos se compararon mediante una prueba no paramétrica. RESULTADOS. En el grupo 1 ambas pruebas mostraron una sensibilidad de 1 y especificidades de 0,98 (Coombs) y 0,95 (Brucellacapt®). En el grupo 2 las sensibilidades fueron de 1 (Coombs) y 0,95 (Brucellacapt®), y las especificidades de 0,80 (Coombs) y 0,74 (Brucellacapt®). En dicho grupo las áreas bajo la curva fueron de 0,950 (Coombs) y 0,904 (Brucellacapt®) .Al comparar los resultados de ambas pruebas mediante la prueba de Wilcoxon no se observaron diferencias estadísticamente significativas (Z= -0,213; p= 0,8). CONCLUSIONES. Los resultados obtenidos en las pruebas de Brucellacapt® y Coombs, empleando sueros en diferentes fases de la enfermedad, pueden considerarse intercambiables ya que ofrecen un rendimiento diagnóstico similar (AU)