scholarly journals Effects of time and isolation on plant diversity: testing island biogeography theory with an eco-evolutionary model

2017 ◽  
Author(s):  
Juliano Sarmento Cabral ◽  
Robert J. Whittaker ◽  
Kerstin Wiegand ◽  
Holger Kreft
Keyword(s):  
Species Richness ◽  
Endemic Species ◽  
Island Biogeography ◽  
Temporal Trends ◽  
Evolutionary Model ◽  
Simulation Models ◽  
Population Level ◽  
Species Number ◽  
Dispersal Ability ◽  
Extinction Rates

abstractAimsThe General Dynamic Model of oceanic island biogeography (GDM) predicts how biogeographical rates, species richness, and endemism vary depending on island age, area, and isolation, based on the interplay of colonization, extinction, and speciation. Here, we used a simulation model to test whether GDM predictions may arise from individual- and population-level processes.LocationHypothetical hotspot islands.MethodsOur model (i) considers an idealized island ontogeny, (ii) metabolic constraints, and (iii) stochastic, spatially-explicit, and niche-based processes at the level of individuals and populations (plant demography, dispersal, competition, mutation, and speciation). Isolation scenarios involved varying dispersal ability and distances to mainland.ResultsHumped temporal trends were obtained for species richness, endemic richness, proportion of cladogenetic endemic species, number of radiating lineages, number of species per radiating lineage, and biogeographical rates. The proportion of anagenetic endemics and of all endemics steadily increased over time. Extinction rates of endemic species peaked later than for non-endemic species. Species richness and the number of anagenetic endemics decreased with isolation as did rates of colonization, anagenesis, and extinction. The proportion of all endemics and of cladogenetic endemics, the number of cladogenetic endemics, of radiating lineages, and of species per radiating lineage, and the cladogenesis rate all increased with isolation.Main conclusionsThe results confirm most GDM predictions related to island ontogeny and isolation, but predict an increasing proportion of endemics throughout the experiment: a difference attributable to diverging assumptions on late island ontogeny. New insights regarding the extinction trends of endemics further demonstrate how simulation models focusing on low ecological levels provide tools to test biogeographical-scale predictions and to develop more detailed predictions for further empirical tests.

Boreal ground-beetle (Coleoptera: Carabidae) assemblages of the mainland and islands in Lac la Ronge, Saskatchewan, Canada

2017 ◽  
Vol 149 (4) ◽  
pp. 491-503 ◽  
Author(s):  
Aaron J. Bell ◽  
Iain D. Phillips ◽  
Scott E. Nielsen ◽  
John R. Spence
Keyword(s):  
Species Richness ◽  
Island Biogeography ◽  
Passive Sampling ◽  
Unit Area ◽  
Ground Beetle ◽  
Small Islands ◽  
Island Size ◽  
Extinction Rates ◽  
Theory Of Island Biogeography ◽  
Species Area

AbstractWe tested the applicability of the “passive sampling” hypothesis and theory of island biogeography (TIB) for explaining the diversity of forest-dwelling carabid assemblages (Carabidae: Coleoptera) on 30 forested islands (0.2–980.7 ha) in Lac la Ronge and the adjacent mainland in Saskatchewan, Canada. Species richness per unit area increased with distance to mainland with diversity being highest on the most isolated islands. We detected neither a positive species-area relationship, nor significant differences in species richness among island size classes, or between islands and the mainland. Nonetheless, carabid assemblages distinctly differed on islands <1 ha in area and gradually approached the structure of mainland assemblages as island area increased. Small islands were characterised by abundant populations of small-bodied, winged species and few if any large-bodied, flightless species like Carabus taedatus Fabricius. Our findings suggest that neither the “passive sampling” hypothesis nor the theory of island biogeography adequately explain carabid beetle diversity patterns observed among islands in Lac la Ronge. Instead, we hypothesise that population processes such as higher extinction rates of large-bodied, flightless species and the associated release of smaller-bodied, flying species from intra-guild predation on small islands contribute to observed differences in the structure of carabid assemblages between islands.

scholarly journals New distributional records for ants and the evaluation of ant species richness and endemism patterns in Mexico

2021 ◽  
Vol 9 ◽  
Author(s):  
Mario J. Aguilar-Méndez ◽  
Madai Rosas-Mejía ◽  
Miguel Vásquez-Bolaños ◽  
Gloria Angélica González-Hernández ◽  
Milan Janda
Keyword(s):  
Species Richness ◽  
Endemic Species ◽  
Service Providers ◽  
Species Number ◽  
Sampling Effort ◽  
Ecological Significance ◽  
Species Richness Estimation ◽  
Narrow Endemic ◽  
Atta Texana ◽  
First Time

Ants (Formicidae) in Mexico have usually been undersampled despite their ecological significance and their utility as environmental service providers and bioindicators. This study estimates the species richness and the narrow endemic species number of ants across Mexico. It also documents the presence of one species newly recorded in Mexico and 19 new state-based records of 14 species from central and north Mexico. No surveys have been performed in most of the localities where we report those records, suggesting the need for a higher sampling effort across the country. We present an ant species richness estimation and a narrow endemic ant species estimation in a grid of 0.5 degrees in Mexico. Stenamma schmitii is recorded for the first time from Mexico. Additionally, new state-based records of Azteca velox, Dorymyrmex insanus, Camponotus coruscus, Camponotus striatus, Formica propatula, Lasius latipes, Neivamyrmex melanocephalus, Neivamyrmex rugulosus, Syscia augustae, Atta texana, Cephalotes scutulatus, Crematogaster crinosa and Temnothorax andrei are recorded.

Diversity-dependent species dynamics: incorporating the effects of population-level processes on species dynamics

Paleobiology ◽  
1989 ◽  
Vol 15 (2) ◽  
pp. 133-146 ◽  
Author(s):  
Brian A. Maurer
Keyword(s):  
Hierarchical Model ◽  
Hierarchical Models ◽  
Logistic Model ◽  
Energy Use ◽  
Population Level ◽  
Species Number ◽  
Data Set ◽  
Extinction Rates ◽  
Species Dynamics ◽  
Biological Hierarchy

A general model of species dynamics must incorporate the effects of species number on the processes of speciation and extinction. Previous models make specific assumptions about these effects, but do not consider the effects of dynamics of lower level entities on speciation and extinction rates. A hierarchical model is developed which explicitly describes the effects of energy use by species on speciation and extinction rates. The effects of energy use are represented by parameters that characterize the average effects of energy use by each species in the biota on speciation and extinction rates. The dynamics of the model describe a sigmoidal increase in species number over time, as does the logistic model of species dynamics. However, the mechanisms of those dynamics are assumed to be different in the two models. Empirical analysis of a data set on the diversification of fossil Miocene horses suggests that the logistic and hierarchical models have similar descriptive power. The hierarchical model incorporates insights from recent considerations of the nature of a hierarchical theory of biology. Further progress in developing such a theory will depend on the success with which relationships among levels in the biological hierarchy are able to be defined.

A population-based analysis in 375,233 cases of heart failure stages A, B and C. Real world epidemiology of prevalence and temporal trends in South-European populations

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S Jimenez ◽  
M Cainzos-Achirica ◽  
D Monterde ◽  
L Garcia-Eroles ◽  
C Enjuanes ◽  
...  
Keyword(s):  
Heart Failure ◽  
Chronic Conditions ◽  
Temporal Trends ◽  
Population Level ◽  
Population Based ◽  
Relative Increase ◽  
Funding Source ◽  
Private Company ◽  
Healthcare Database ◽  
Evolutionary Changes

Abstract Background Prevalence of congestive heart failure (CHF) and predisposing conditions has described previously. Most of these studies evaluated centre-European or north-American populations. However, the prevalence and evolutionary changes of Heart Failure stages A, B and C has not been fully elucidated in Mediterranean cohorts. Purpose To estimate the prevalence of CHF (HF Stage C) and four additional key chronic cardiovascular, metabolic and renal conditions predisposing to the development of CHF (HF Stages A and B) at a population level in a south-European healthcare area. We analysed the evolutionary changes in the prevalence in these five conditions. Methods In a healthcare area of 1,3Millions inhabitants, we extracted health related information of all individuals ≥55 years old. We analysed data of 375,233 individuals included in the population-based healthcare database of a public Institute of Health between 2015 and 2017. The conditions of interest were CHF, chronic kidney disease (CKD), diabetes mellitus (DM), ischemic heart disease (IHD) and hypertension (HTN). Results The prevalence of chronic conditions was high, particularly of HTN (48.2–48.9%) and DM individuals (14.6–14.8%). The other conditions were less frequent, with prevalence around 2–4% for IHD, 5–9% for CKD and 2–4% for CHF (Table). However, the less frequent conditions had a striking upward trend with over 1,500 new prevalent cases per year between 2015 and 2017 for CHF (45% relative increase), more than 2,500 new prevalent cases for IHD (67% relative increase) and more than 4,000 new prevalent cases per year for CKD (44% relative increase). Conclusion In this south European cohort, there were a high prevalence of HTN and DM as risk factors and a significant trend of increasing prevalence in high cost chronic conditions such as CHF, IHD and CKD. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): The present study was funded by an unrestricted research grant from Vifor Pharma.

scholarly journals Spatio-temporal impacts of aerial adulticide applications on populations of West Nile virus vector mosquitoes

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Karen M. Holcomb ◽  
Robert C. Reiner ◽  
Christopher M. Barker
Keyword(s):  
West Nile Virus ◽  
Temporal Trends ◽  
Larval Habitat ◽  
Post Treatment ◽  
Additive Models ◽  
Dispersal Ability ◽  
Stochastic Variation ◽  
West Nile ◽  
Spatial Coverage ◽  
Spatio Temporal

Abstract Background Aerial applications of insecticides that target adult mosquitoes are widely used to reduce transmission of West Nile virus to humans during periods of epidemic risk. However, estimates of the reduction in abundance following these treatments typically focus on single events, rely on pre-defined, untreated control sites and can vary widely due to stochastic variation in population dynamics and trapping success unrelated to the treatment. Methods To overcome these limitations, we developed generalized additive models fitted to mosquito surveillance data collected from CO2-baited traps in Sacramento and Yolo counties, California from 2006 to 2017. The models accounted for the expected spatial and temporal trends in the abundance of adult female Culex (Cx.) tarsalis and Cx. pipiens in the absence of aerial spraying. Estimates for the magnitude of deviation from baseline abundance following aerial spray events were obtained from the models. Results At 1-week post-treatment with full spatial coverage of the trapping area by pyrethroid or pyrethrin products, Cx. pipiens abundance was reduced by a mean of 52.4% (95% confidence intrval [CI] − 65.6, − 36.5%) while the use of at least one organophosphate pesticide resulted in a mean reduction of 76.2% (95% CI − 82.8, − 67.9%). For Cx. tarsalis, at 1-week post-treatment with full coverage there was a reduction in abundance of 30.7% (95% CI − 54.5, 2.5%). Pesticide class was not a significant factor contributing to the reduction. In comparison, repetition of spraying over three to four consecutive weeks resulted in similar estimates for Cx. pipiens and estimates of somewhat smaller magnitude for Cx. tarsalis. Conclusions Aerial adulticides are effective for achieving a rapid short-term reduction of the abundance of the primary West Nile virus vectors, Cx. tarsalis and Cx. pipiens. A larger magnitude of reduction was estimated in Cx. pipiens, possibly due to the species’ focal distribution. Effects of aerial sprays on Cx. tarsalis populations are likely modulated by the species’ large dispersal ability, population sizes and vast productive larval habitat present in the study area. Our modeling approach provides a new way to estimate effects of public health pesticides on vector populations using routinely collected observational data and accounting for spatio-temporal trends and contextual factors like weather and habitat. This approach does not require pre-selected control sites and expands upon past studies that have focused on the effects of individual aerial treatment events.

An island biogeography model for beta diversity and endemism: The roles of speciation, extinction and dispersal

2015 ◽  
Vol 08 (01) ◽  
pp. 1550011 ◽  
Author(s):  
Youhua Chen
Keyword(s):  
Numerical Simulation ◽  
Community Composition ◽  
Beta Diversity ◽  
Island Biogeography ◽  
Positive Relationship ◽  
Community Patterns ◽  
Speciation Rate ◽  
Immigration Rate ◽  
Extinction Rates

A community composition island biogeography model was developed to explain and predict two community patterns (beta diversity and endemism) with the consideration of speciation, extinction and dispersal processes. Results showed that rate of speciation is positively and linearly associated with beta diversity and endemism, that is, increasing species rates typically could increase the percentage of both endemism and beta diversity. The influences of immigration and extinction rates on beta diversity and endemism are nonlinear, but with numerical simulation, I could observe that increasing extinction rates would lead to decreasing percentage of endemism and beta diversity. The role of immigration rate is very similar to that of speciation rate, having a positive relationship with beta diversity and endemism. Finally, I found that beta diversity is closely related to the percentage of endemism. The slope of this positive relationship is determined jointly by different combinations of speciation, extinction and immigration rates.

scholarly journals PRESERVATION OF PRIMARY FOREST CHARACTERISTICS DESPITE FRAGMENTATION AND ISOLATION IN A FOREST REMNANT FROM VIÇOSA, MG, BRAZIL1

2015 ◽  
Vol 39 (6) ◽  
pp. 985-994 ◽  
Author(s):  
Markus Gastauer ◽  
Marcos Eduardo Guerra Sobral ◽  
João Augusto Alves Meira-Neto
Keyword(s):  
Species Richness ◽  
Endemic Species ◽  
Tree Species ◽  
Primary Forest ◽  
Forest Patch ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Forest Remnant ◽  
Primary Forests ◽  
Biotic Resources

According to its owners, the Forest of Seu Nico (FSN) from the Viçosa municipality, Minas Gerais, Brazil, never has been logged and is therefore considered a primary forest. Nevertheless, the forest patch suffered impacts due to selective wood and non-timber extraction, fragmentation and isolation. Aim of this study was to test if the FSN, despite impacts, preserved characteristics of primary forests, which are elevated percentages of non-pioneer (>90%), animal-dispersed (>80 %), understory (>50%) and endemic species (~40%). For that, all trees with diameter at breast height equal or major than 3.2 cm within a plot of 100 x 100 m were identified. With 218 tree species found within this hectare, the FSN's species richness is outstanding for the region. The percentages of non-pioneer (92 %), animal-dispersed (85 %), understory (55 %) and endemic species (39.2 %) from the FSN fulfill the criteria proposed for primary forest. Therefore, we conclude that the FSN maintained its characteristics as a primary forest which highlights its importance for the conservation of biotic resources in the region, where similar fragments are lacking or not described yet.

scholarly journals Anurans of the Parque Estadual do Mirador, a remnant of Cerrado in the state of Maranhão, Northeastern Brazil

2017 ◽  
Vol 17 (4) ◽  
Author(s):  
Etielle Barroso de Andrade ◽  
Luiz Norberto Weber ◽  
José Roberto de Souza Almeida Leite
Keyword(s):  
Species Richness ◽  
Central Region ◽  
Wide Distribution ◽  
The State ◽  
Northeastern Brazil ◽  
Species Number ◽  
Sampling Effort ◽  
The South ◽  
Cerrado Biome ◽  
South Central

Abstract The Cerrado is one of the most threatened biomes in Brazil. It is estimated that much of its original vegetation has been replaced by some type of human use. This is quite worrying, mainly in the northern part where the number of wildlife inventories is insufficient and creates the false impression of low diversity in the region. The Parque Estadual do Mirador-PEM, located in the south-central region of the state of Maranhão, presents vegetation typical of the Cerrado biome and corresponds to one of 46 priority areas for conservation in the state. Herein, we describe the species richness and composition of the anurofauna from the PEM and analyze the influence of different types of vegetation in its formation. Our inventory was conducted from December 2013 to February 2015, using the active search and auditory census methods on breeding sites in different water bodies of the park. We recorded 31 anuran species belonging to five families (species number in parentheses): Leptodactylidae (14), Hylidae (12), Bufonidae (3), Microhylidae (1) and Phyllomedusidae (1). The rarefaction curve and species richness estimators indicated that the sampling effort was enough to record most of the species in the region. The richness of anurans in the PEM was higher than reported by other authors for several areas of Cerrado. Most species have a wide distribution in Brazil or are strongly associated with the Caatinga or Amazon biomes. Only about 19% are endemic to the Cerrado biome. This study is the first to inventory the anurans species of the south-central region of state of Maranhão and provides important data on amphibian communities from the northern part of the Brazilian Cerrado.

scholarly journals The role of dispersal for shaping phylogeographical structure of flightless beetles from the Andes

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7226 ◽  
Author(s):  
Sofia I. Muñoz-Tobar ◽  
Michael S. Caterino
Keyword(s):  
Mitochondrial Gene ◽  
Ground Beetle ◽  
Population Level ◽  
Population Subdivision ◽  
Dispersal Ability ◽  
Population Isolation ◽  
Small Areas ◽  
Maximum Entropy Models ◽  
The Andes

Background Páramo is a tropical alpine ecosystem present in the northern Andes. Its patchy distribution imposes limits and barriers to specialist inhabitants. We aim to assess the effects of this habitat distribution on divergence across two independently flightless ground beetle lineages, in the genera Dyscolus and Dercylus. Methods One nuclear and one mitochondrial gene from 110 individuals from 10 sites across the two lineages were sequenced and analyzed using a combination of phylogenetics, population genetic analyses, and niche modeling methods. Results The two lineages show different degrees of population subdivision. Low levels of gene flow were found in Dyscolus alpinus, where one dominant haplotype is found in four out of the six populations analyzed for both molecular markers. However, complete population isolation was revealed in species of the genus Dercylus, where high levels of differentiation exist at species and population level for both genes. Maximum entropy models of species in the Dercylus lineage show overlapping distributions. Still, species distributions appear to be restricted to small areas across the Andes. Conclusion Even though both beetle lineages are flightless, the dispersal ability of each beetle lineage appears to influence the genetic diversity across fragmented páramo populations, where Dyscolus alpinus appears to be a better disperser than species in the genus Dercylus.

Temporal Trends in the Microbiological Characteristics of Sepsis in the United States: A Population Based Study

2021 ◽  
pp. 088506662110537
Author(s):  
Po-Yang Tsou ◽  
Chia-Hung Yo ◽  
Yenh-Chen Hsein ◽  
Gregory Yungtum ◽  
Wan-Ting Hsu ◽  
...  
Keyword(s):  
United States ◽  
Temporal Trends ◽  
Population Level ◽  
The United States ◽  
Population Based ◽  
Epidemiologic Studies ◽  
Annual Increase ◽  
Gram Negative ◽  
Nationwide Inpatient Sample Database ◽  
Incidence And Mortality

Background Epidemiologic studies are needed for monitoring population-level trends in sepsis. This study examines sepsis-causing microorganisms from 2006 to 2014 in the United States using data from the Nationwide Inpatient Sample database. Methods 7 860 686 adults hospitalized with sepsis were identified using a validated ICD-9 coding approach. Associated microorganisms were identified by ICD-9 code and classified by major groups (Gram-positive, Gram-negative, fungi, anaerobes) and specific species for analysis of their incidence and mortality. Results The rate of sepsis incidence has increased for all four major categories of pathogens, while the mortality rate decreased. In 2014, Gram-negative pathogens had a higher incidence than Gram-positives. Anaerobes increased the fastest with an average annual increase of 20.17% (p < 0.001). Fungi had the highest mortality (19.28%) and the slowest annual decrease of mortality (−2.31%, p = 0.006) in 2013, while anaerobic sepsis had the highest hazard of mortality (adjusted HR 1.60, 95% CI 1.53-1.66). Conclusions Gram-negative pathogens have replaced Gram-positives as the leading cause of sepsis in the United States in 2014 during the study period (2006-2014). The incidence of anaerobic sepsis has an annual increase of 20%, while the mortality of fungal sepsis has not decreased at the same rate as other microorganisms. These findings should inform the diagnosis and management of septic patients, as well as the implementation of public health programs.

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