scholarly journals Late Miocene origin and recent population collapse of the Malagasy savanna olive tree (Noronhia lowryi)

2019 ◽  
Vol 129 (1) ◽  
pp. 227-243 ◽  
Author(s):  
Jordi Salmona ◽  
Jill K Olofsson ◽  
Cynthia Hong-Wa ◽  
Jacqueline Razanatsoa ◽  
Franck Rakotonasolo ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Abiotic Factors ◽  
Demographic History ◽  
Olive Tree ◽  
Nuclear Data ◽  
Chloroplast Microsatellites ◽  
Population Genetic Analysis ◽  
Central Plateau ◽  
Habitat Mosaics

Abstract Debates regarding the origin of tropical savannas have attempted to disentangle the role of human, biotic and abiotic factors. Understanding the origins of savanna remains essential to identifying processes that gave rise to habitat mosaics, particularly those found in the Central Plateau of Madagascar. Documenting the evolutionary history and demography of native trees occurring in open habitats may reveal footprints left by past and recent environmental changes. We conducted a population genetic analysis of an endangered Malagasy shrub (Noronhia lowryi, Oleaceae) of the Central Plateau. Seventy-seven individuals were sampled from three sites and genotyped at 14 nuclear and 24 chloroplast microsatellites. We found a highly contrasting nuclear and plastid genetic structure, suggesting that pollen-mediated gene flow allows panmixia, while seed-based dispersal may rarely exceed tens of metres. From a phylogeny based on full plastomes, we dated the surprisingly old crown age of maternal lineages back to ~6.2 Mya, perhaps co-occurring with the global expansion of savanna. In contrast, recent demographic history inferred from nuclear data shows a bottleneck signature ~350 generations ago, probably reflecting an environmental shift during the Late Pleistocene or the Holocene. Ancient in situ adaptation and recent demographic collapse of an endangered woody plant highlight the unique value and vulnerability of the Malagasy savannas.

scholarly journals Quaternary climate changes as speciation drivers in the Amazon floodplains

2020 ◽  
Vol 6 (11) ◽  
pp. eaax4718 ◽  
Author(s):  
Gregory Thom ◽  
Alexander T. Xue ◽  
André O. Sawakuchi ◽  
Camila C. Ribas ◽  
Michael J. Hickerson ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Demographic History ◽  
Secondary Contact ◽  
Phylogenomic Analysis ◽  
Population Isolation ◽  
Quaternary Climate ◽  
Species Complexes ◽  
Historical Processes ◽  
Quaternary Climate Changes

The role of climate as a speciation driver in the Amazon has long been discussed. Phylogeographic studies have failed to recover synchronous demographic responses across taxa, although recent evidence supports the interaction between rivers and climate in promoting speciation. Most studies, however, are biased toward upland forest organisms, while other habitats are poorly explored and could hold valuable information about major historical processes. We conducted a comparative phylogenomic analysis of floodplain forest birds to explore the effects of historical environmental changes and current connectivity on population differentiation. Our findings support a similar demographic history among species complexes, indicating that the central portion of the Amazon River basin is a suture zone for taxa isolated across the main Amazonian sub-basins. Our results also suggest that changes in the fluvial landscape induced by climate variation during the Mid- and Late Pleistocene drove population isolation, leading to diversification with subsequent secondary contact.

scholarly journals Demographic history and genomic response to environmental changes in a rapid radiation of wild rats

2021 ◽  
Author(s):  
Deyan Ge ◽  
Anderson Feijó ◽  
Zhixin Wen ◽  
Alexei V Abramov ◽  
Liang Lu ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Demographic History ◽  
Terrestrial Ecosystems ◽  
Tibet Plateau ◽  
Global Changes ◽  
Rapid Radiation ◽  
Protein Functions ◽  
Wild Rats ◽  
Qinghai Tibet Plateau ◽  
Genomic Response

Abstract For organisms to survive and prosper in a harsh environment, particularly under rapid climate change, poses tremendous challenges. Recent studies have highlighted the continued loss of megafauna in terrestrial ecosystems and the subsequent surge of small mammals, such as rodents, bats, lagomorphs, and insectivores. However, the ecological partitioning of these animals will likely lead to large variation in their responses to environmental change. In the present study, we investigated the evolutionary history and genetic adaptations of white-bellied rats (Niviventer Marshall, 1976), which are widespread in the natural terrestrial ecosystems in Asia but also known as important zoonotic pathogen vectors and transmitters. The southeastern Qinghai-Tibet Plateau (QHTP) was inferred as the origin center of this genus, with parallel diversification in temperate and tropical niches. Demographic history analyses from mitochondrial and nuclear sequences of Niviventer demonstrated population size increases and range expansion for species in Southeast Asia, and habitat generalists elsewhere. Unexpectedly, population increases were seen in N. eha, which inhabits the highest elevation among Niviventer species. Genome scans of nuclear exons revealed that among the congeneric species, N. eha has the largest number of positively selected genes. Protein functions of these genes are mainly related to olfaction, taste and tumor suppression. Extensive genetic modification presents a major strategy in response to global changes in these alpine species.

scholarly journals Cytotype distribution and chloroplast phylogeography of the Actinidia chinensis complex

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhi Wang ◽  
Caihong Zhong ◽  
Dawei Li ◽  
Chunlin Yan ◽  
Xiaohong Yao ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Demographic History ◽  
Wide Distribution ◽  
Historical Demography ◽  
Actinidia Chinensis ◽  
Ecological Niche Models ◽  
Subtropical China ◽  
Modeling Tools ◽  
Climatic Fluctuations ◽  
Ploidy Levels

Abstract Background Plant phylogeographic studies of species in subtropical China have mainly focused on rare and endangered species, whereas few studies have been conducted on taxa with relatively wide distribution, especially polyploid species. We investigated the cytotype and haplotype distribution pattern of the Actinidia chinensis complex, a widespread geographically woody liana with variable ploidy in subtropical China comprising two varieties, with three chloroplast fragments DNA (ndhF-rpl132, rps16-trnQ and trnE-trnT). Macroevolutionary, microevolutionary and niche modeling tools were also combined to disentangle the origin and the demographic history of the species or cytotypes. Results The ploidy levels of 3338 individuals from 128 populations sampled throughout the species distribution range were estimated with flow cytometry. The widespread cytotypes were diploids followed by tetraploids and hexaploids, whereas triploids and octoploids occurred in a few populations. Thirty-one chloroplast haplotypes were detected. The genetic diversity and genetic structure were found to be high between varieties (or ploidy races) chinensis and deliciosa. Our results revealed that these two varieties inhabit significantly different climatic niche spaces. Ecological niche models (ENMs) indicate that all varieties’ ranges contracted during the Last Inter Glacial (LIG), and expanded eastward or northward during the Last Glacial Maximum (LGM). Conclusions Pliocene and Plio-Pleistocene climatic fluctuations and vicariance appear to have played key roles in shaping current population structure and historical demography in the A. chinensis complex. The polyploidization process also appears to have played an important role in the historical demography of the complex through improving their adaptability to environmental changes.

scholarly journals Testing the spatial and temporal framework of speciation in an ancient lake species flock: the leech genus <i>Dina</i> (Hirudinea: Erpobdellidae) in Lake Ohrid

2010 ◽  
Vol 7 (11) ◽  
pp. 3387-3402 ◽  
Author(s):  
S. Trajanovski ◽  
C. Albrecht ◽  
K. Schreiber ◽  
R. Schultheiß ◽  
T. Stadler ◽  
...  
Keyword(s):  
Molecular Clock ◽  
Abiotic Factors ◽  
Time Frame ◽  
Recent Common Ancestor ◽  
Species Flock ◽  
Ancient Lake ◽  
Lake Ohrid ◽  
Most Recent Common Ancestor ◽  
Extant Species

Abstract. Ancient Lake Ohrid on the Balkan Peninsula is considered to be the oldest ancient lake in Europe with a suggested Plio-/Pleistocene age. Its exact geological age, however, remains unknown. Therefore, molecular clock data of Lake Ohrid biota may serve as an independent constraint of available geological data, and may thus help to refine age estimates. Such evolutionary data may also help unravel potential biotic and abiotic factors that promote speciation events. Here, mitochondrial sequencing data of one of the largest groups of endemic taxa in the Ohrid watershed, the leech genus Dina, is used to test whether it represents an ancient lake species flock, to study the role of potential horizontal and vertical barriers in the watershed for evolutionary events, to estimate the onset of diversification in this group based on molecular clock analyses, and to compare this data with data from other endemic species for providing an approximate time frame for the origin of Lake Ohrid. Based on the criteria speciosity, monophyly and endemicity, it can be concluded that Dina spp. from the Ohrid watershed, indeed, represents an ancient lake species flock. Lineage sorting of its species, however, does not seem to be complete and/or hybridization may occur. Analyses of population structures of Dina spp. in the Ohrid watershed indicate a horizontal zonation of haplotypes from spring and lake populations, corroborating the role of lake-side springs, particularly the southern feeder springs, for evolutionary processes in endemic Ohrid taxa. Vertical differentiation of lake taxa, however, appears to be limited, though differences between populations from the littoral and the profundal are apparent. Molecular clock analyses indicate that the most recent common ancestor of extant species of this flock is approximately 1.99 ± 0.83 million years (Ma) old, whereas the split of the Ohrid Dina flock from a potential sister taxon outside the lake is estimated at 8.30 ± 3.60 Ma. Comparisons with other groups of endemic Ohrid species indicated that in all cases, diversification within the watershed started ≤2 Ma ago. Thus, this estimate may provide information on a minimum age for the origin of Lake Ohrid. Maximum ages are less consistent and generally less reliable. But cautiously, a maximum age of 3 Ma is suggested. Interestingly, this time frame of approximately 2–3 Ma ago for the origin of Lake Ohrid, generated based on genetic data, well fits the time frame most often used in the literature by geologists.

ROLE OF ABIOTIC FACTORS IN GOVERNING SUSCEPTIBILITY TO INVASION: A TEST WITH ARGENTINE ANTS

Ecology ◽  
2002 ◽  
Vol 83 (6) ◽  
pp. 1610-1619 ◽  
Author(s):  
David A. Holway ◽  
Andrew V. Suarez ◽  
Ted J. Case
Keyword(s):  
Abiotic Factors ◽  
Argentine Ants

The Colorado potato beetle in movement

2003 ◽  
Vol 135 (1) ◽  
pp. 1-22 ◽  
Author(s):  
G. Boiteau ◽  
A. Alyokhin ◽  
D.N. Ferro
Keyword(s):  
Colorado Potato Beetle ◽  
Leptinotarsa Decemlineata ◽  
Recent Literature ◽  
Abiotic Factors ◽  
Orientation Process ◽  
Potato Beetle ◽  
Host Habitat ◽  
Subject Areas ◽  
Refuge Areas

AbstractThe recent introduction of the concept of refuge areas for the management of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera : Chrysomelidae), on resistant potato highlighted the existence of important gaps in our knowledge and understanding of this pest's movement within and between habitats. The objective of this review is to synthesize the information available for the benefit of crop managers and to identify subject areas in need of additional research. A traditional, somewhat encyclopedic, review of the old and recent literature on research methods, basics of flight and walking, as well as abiotic and biotic conditions for dispersal, revealed a considerable volume of information accumulated since the early 1900s. There is a consensus on the role of abiotic factors on flight and walking, but a better understanding of the biotic factors will be required before the variability of the dispersal response can be fully explained or predicted. Cybernetic models of orientation proposed in the literature were pulled together into a schematic representation of the orientation process in walking L. decemlineata. The model begins the integration of the different conditions and underlying suggested mechanisms responsible for the orientation of the walking beetle. There is remarkably little information on the orientation of potato beetles during flight. Finally, the seasonality of walking and flight dispersal is reviewed in relation to the host habitat and overwintering sites.

Centering microbes in the emerging role of integrative biology in understanding environmental change

2021 ◽  
Author(s):  
Ebony I Weems ◽  
Noé U de la Sancha ◽  
Laurel J Anderson ◽  
Carlos Zambrana-Torrelio ◽  
Ronaldo P Ferraris
Keyword(s):  
Infectious Disease ◽  
Gut Microbiome ◽  
Environmental Changes ◽  
Scale Effects ◽  
Environmental Pollutants ◽  
Data Sets ◽  
Integrative Biology ◽  
Concerted Effort ◽  
Ecosystem Disturbance

Synopsis We argue that the current environmental changes stressing the Earth’s biological systems urgently require study from an integrated perspective to reveal unexpected, cross-scale interactions, particularly between microbes and macroscale phenomena. Such interactions are the basis of a mechanistic understanding of the important connections between deforestation and emerging infectious disease, feedback between ecosystem disturbance and the gut microbiome, and the cross-scale effects of environmental pollutants. These kinds of questions can be answered with existing techniques and data, but a concerted effort is necessary to better coordinate studies and data sets from different disciplines to fully leverage their potential.

scholarly journals The Protective Role of Butyrate against Obesity and Obesity-Related Diseases

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 682
Author(s):  
Serena Coppola ◽  
Carmen Avagliano ◽  
Antonio Calignano ◽  
Roberto Berni Canani
Keyword(s):  
Metabolic Diseases ◽  
Environmental Changes ◽  
Short Chain Fatty Acids ◽  
Protective Role ◽  
Health Concern ◽  
Predisposing Factor ◽  
Alcoholic Fatty Liver ◽  
Beneficial Effects ◽  
The Individual

Worldwide obesity is a public health concern that has reached pandemic levels. Obesity is the major predisposing factor to comorbidities, including type 2 diabetes, cardiovascular diseases, dyslipidemia, and non-alcoholic fatty liver disease. The common forms of obesity are multifactorial and derive from a complex interplay of environmental changes and the individual genetic predisposition. Increasing evidence suggest a pivotal role played by alterations of gut microbiota (GM) that could represent the causative link between environmental factors and onset of obesity. The beneficial effects of GM are mainly mediated by the secretion of various metabolites. Short-chain fatty acids (SCFAs) acetate, propionate and butyrate are small organic metabolites produced by fermentation of dietary fibers and resistant starch with vast beneficial effects in energy metabolism, intestinal homeostasis and immune responses regulation. An aberrant production of SCFAs has emerged in obesity and metabolic diseases. Among SCFAs, butyrate emerged because it might have a potential in alleviating obesity and related comorbidities. Here we reviewed the preclinical and clinical data that contribute to explain the role of butyrate in this context, highlighting its crucial contribute in the diet-GM-host health axis.

scholarly journals Monitoring studies should consider temporal variability to reveal relations between cyanobacterial abundance and environmental variables

2015 ◽  
Vol 87 (3) ◽  
pp. 1717-1726 ◽  
Author(s):  
JULIANA WOJCIECHOWSKI ◽  
ANDRÉ A. PADIAL
Keyword(s):  
Temporal Variability ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Time Lag ◽  
Cyanobacteria Blooms ◽  
Environment Variables ◽  
Sampling Points ◽  
The Relationship

One of the main goals of monitoring cyanobacteria blooms in aquatic environments is to reveal the relationship between cyanobacterial abundance and environmental variables. Studies typically correlate data that were simultaneously sampled. However, samplings occur sparsely over time and may not reveal the short-term responses of cyanobacterial abundance to environmental changes. In this study, we tested the hypothesis that stronger cyanobacteria x environment relationships in monitoring are found when the temporal variability of sampling points is incorporated in the statistical analyses. To this end, we investigated relationships between cyanobacteria and seven environmental variables that were sampled twice yearly for three years across 11 reservoirs, and data from an intensive monitoring in one of these reservoirs. Poor correlations were obtained when correlating data simultaneously sampled. In fact, the 'highly recurrent' role of phosphorus in cyanobacteria blooms is not properly observed in all sampling periods. On the other hand, the strongest correlation values for the total phosphorus x cyanobacteria relationship were observed when we used the variation of sampling points. We have also shown that environment variables better explain cyanobacteria when a time lag is considered. We conclude that, in cyanobacteria monitoring, the best approach to reveal determinants of cyanobacteria blooms is to consider environmental variability.

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