scholarly journals Late Quaternary Environmental and Human Impacts on the Mitochondrial DNA Diversity of Four Commensal Rodents in Myanmar

2020 ◽  
Author(s):  
San Maung Maung Theint ◽  
Thidalay Thwe ◽  
Khin Myat Myat Zaw ◽  
Tomofumi Shimada ◽  
Saw Bawm ◽  
...  
Keyword(s):  
Human Impacts ◽  
Late Quaternary ◽  
Rattus Rattus ◽  
Rapid Expansion ◽  
Rodent Species ◽  
Bandicota Bengalensis ◽  
Nearby Region ◽  
The Pacific ◽  
Sequence Variations ◽  
Commensal Rodents

Abstract We addressed the spatiotemporal characteristics of four commensal rodent species occurring in Myanmar in comparison with other areas of the Indo-Malayan region. We examined sequence variations of the mitochondrial cytochrome b gene (Cytb) in the Pacific rat (Rattus exulans), roof rat (Rattus rattus complex, RrC), lesser bandicoot rat (Bandicota bengalensis), and house mouse (Mus musculus) using the recently developed time-dependent evolutionary rates of mtDNA. The Cytb sequences of RrC from Myanmar were shown to belong to RrC Lineage II, and their level of genetic diversity was relatively high compared to those of the other three species. RrC was found to have experienced bottleneck and rapid expansion events at least twice in the late Pleistocene period in Myanmar and a nearby region. Accordingly, paleoclimatic environmental fluctuations were shown to be an important factor affecting rodents in the subtropics of the Indo-Malayan region. Our results show that human activities during the last 10,000 years of the Holocene period affected the population dynamics of the rodent species examined, including introducing them to Myanmar from neighboring countries. Further study of these four commensal rodents in other geographic areas of the Indo-Malayan region would allow us to better understand the factors that drove their evolution and their ecological trends.

Identification of Dacitic Tephra by Activation Analysis of their Primary Mineral Phenocrysts

1973 ◽  
Vol 3 (2) ◽  
pp. 307-315 ◽  
Author(s):  
M.J. Dudas ◽  
M.E. Harward ◽  
R.A. Schmitt
Keyword(s):  
Rare Earth ◽  
Activation Analysis ◽  
Pacific Northwest ◽  
Late Quaternary ◽  
Minor Element ◽  
Transition Elements ◽  
Pyroclastic Deposits ◽  
Element Abundances ◽  
The Pacific ◽  
Primary Mineral

AbstractPrimary mineral phenocrysts from eight different late Quaternary pyroclastic deposits were fractionated for neutron-activation analysis with the purpose of characterizing each of the deposits on the basis of trace and minor element compositions. In hornblende separates, contents of several rare earth and transition elements were found to be distinctive for the Mazama, Glacier Peak, and several St. Helens deposits. In magnetites, abundances of transition elements are characteristic and serve as good discriminants for the pyroclastic deposits examined in this investigation. Contents of transition and rare earth elements in hyperthenes also appear useful in distinguishing volcanic ash deposits. Trace and minor element abundances in plagioclase phenocrysts did not appear adequate for identification of pyroclastics due to elemental depletion and similarity of contents for feldspar separates. It was found that contents of Sm and Yb in hornblende phenocrysts would serve to distinguish between several pyroclastic deposits from the Pacific Northwest.

scholarly journals Influence of Quaternary environmental changes on mole populations inferred from mitochondrial sequences and evolutionary rate estimation

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Azusa Nakamoto ◽  
Masashi Harada ◽  
Reiko Mitsuhashi ◽  
Kimiyuki Tsuchiya ◽  
Alexey P. Kryukov ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Environmental Changes ◽  
Late Quaternary ◽  
Population Expansion ◽  
Rapid Expansion ◽  
Dependent Manner ◽  
Distribution Analysis ◽  
Land Bridge ◽  
Mismatch Distribution Analysis ◽  
Expansion Event

AbstractQuaternary environmental changes fundamentally influenced the genetic diversity of temperate-zone terrestrial animals, including those in the Japanese Archipelago. The genetic diversity of present-day populations is taxon- and region-specific, but its determinants are poorly understood. Here, we analyzed cytochrome b gene (Cytb) sequences (1140 bp) of mitochondrial DNA (mtDNA) to elucidate the factors determining the genetic variation in three species of large moles: Mogera imaizumii and Mogera wogura, which occur in central and southern mainland Japan (Honshu, Shikoku, and Kyushu), and Mogera robusta, which occurs on the nearby Asian continent. Network construction with the Cytb sequences revealed 10 star-shaped clusters with apparent geographic affinity. Mismatch distribution analysis showed that modes of pairwise nucleotide differences (τ values) were grouped into five classes in terms of the level, implying the occurrence of five stages for rapid expansion. It is conceivable that severe cold periods and subsequent warm periods during the late Quaternary were responsible for the population expansion events. The first and third oldest events included island-derived haplotypes, indicative of the involvement of land bridge formation between remote islands, hence suggesting an association of the ends of the penultimate (PGM, ca. 130,000 years ago) and last (LGM, ca. 15,000 years ago) glacial maxima, respectively. Since the third event was followed by the fourth, it is plausible that the termination of the Younger Dryas and subsequent abrupt warming ca. 11,500 years ago facilitated the fourth expansion event. The second event most likely corresponded to early marine isotope stage (MIS) 3 (ca. 53,000 years ago) when the glaciation and subsequent warming period were predicted to have influenced biodiversity. Utilization of the critical times of 130,000, 53,000, 15,000, and 11,500 years ago as calibration points yielded evolutionary rates of 0.03, 0.045, 0.10 and 0.10 substitutions/site/million years, respectively, showing a time-dependent manner whose pattern was similar to that seen in small rodents reported in our previous studies. The age of the fifth expansion event was calculated to be 5800 years ago with a rate of 0.10 substitutions/site/million years ago during the mid-Holocene, suggestive of the influence of humans or other unspecified reasons, such as the Jomon marine transgression.

Micromammals and the Late Quaternary of southern Africa

2021 ◽  
Author(s):  
D.M. Avery
Keyword(s):  
Iron Age ◽  
Southern Africa ◽  
Late Quaternary ◽  
Rattus Rattus ◽  
Analytical Techniques ◽  
Small Samples ◽  
Pinnacle Point ◽  
Human Movements ◽  
Geographical Scale ◽  
Land Mammal

Abstract Improvements in excavation methods, dating, analytical techniques and statistical applications have all led to a substantial increase in recoverable environmental evidence from micromammals. Because these animals are so small the information they provide is on a smaller geographical scale than that afforded by most other lines of evidence. However, with increasing amounts of data and greater interpretational precision in all spheres, the chances are improving of being able to mesh information from different scales. Blombos, Pinnacle Point and Klasies River on the southern coast of South Africa have clearly demonstrated that micromammalian data can contribute to multidisciplinary interpretations of past conditions, in this case during MIS 5 and 6. Little attention has been paid to the generally small samples from Iron Age sites but the presence of the House rat Rattus rattus may provide important information about human movements and may also contribute to our understanding of the Anthropocene once this has been formally defined. Micromammals have not yet been used as chronostratigraphic indicators in southern Africa but it may be possible to develop biochronologies using them and to incorporate this material into African Land Mammal Ages.

Paleoecology in the Pacific Northwest I. Late Quaternary vegetation and climate

1981 ◽  
Vol 21 (2) ◽  
pp. 730-737
Author(s):  
Matsuo Tsukada ◽  
Shinya Sugita ◽  
Dennis M. Hibbert
Keyword(s):  
Pacific Northwest ◽  
Late Quaternary ◽  
The Pacific ◽  
Vegetation And Climate

The ecological impacts of commensal species: black rats, Rattus rattus, at the urban–bushland interface

2015 ◽  
Vol 42 (2) ◽  
pp. 86 ◽  
Author(s):  
Peter B. Banks ◽  
Helen M. Smith
Keyword(s):  
Exotic Species ◽  
Urban Areas ◽  
Rattus Rattus ◽  
Research Priorities ◽  
Ecological Impacts ◽  
Black Rat ◽  
Urban Impacts ◽  
Commensal Species ◽  
Commensal Rodents ◽  
Black Rats

Exotic species have had devastating impacts worldwide and are a major threat to native wildlife. Human commensal species (hereafter commensals) are a special class of exotic species that live largely off the resources associated with human activity. The encroachment of commensals from an urban area into surrounding bushland has been frequently overlooked as an important component of urban impacts, even though human-commensals are common to many urban regions globally. In this review, we present theoretical and empirical evidence for the processes and outcomes occurring when exotic commensal species encroach into native bushland. Specifically we ask when, how and why exotic commensal species encroach into bushland, what determines whether they establish, and what are the ecological consequences. We focus on the black rat, Rattus rattus, arguably the archetypal commensal species with a cosmopolitan distribution and the greatest potential for ecological damage of all the commensal rodents. We expect that the processes that we outline apply to other commensal species more broadly. We argue that commensals are in fact natives of the urban milieu and only become alien when they encroach into peri-urban bushland. We propose that the mechanisms of this encroachment will be different from those of other, non-commensal exotic species because urban areas act as dispersal hubs to overcome many of the barriers of invasion that other exotic species face. We suggest that resource supplementation by urban areas creates a great potential for promoting encroachment, invasion as well as impact. However, biotic and abiotic barriers to invasion are still relevant for commensals, highlighting the need to maintain the integrity of ecosystems and wildlife populations in urban edges so as to prevent commensal incursion. We examine how commensal black rats affect wildlife via three fundamental mechanisms, namely, predation, disease transfer and competition for resources, and also consider their possible positive impacts acting as functional replacements for lost natives. We conclude the review with an outline of research priorities and future directions that are essential for progressing our understanding of the ecology of commensal species.

scholarly journals Rapid reorganization in ocean biogeochemistry off Peru towards the end of the Little Ice Age

2009 ◽  
Vol 6 (5) ◽  
pp. 835-848 ◽  
Author(s):  
D. Gutiérrez ◽  
A. Sifeddine ◽  
D. B. Field ◽  
L. Ortlieb ◽  
G. Vargas ◽  
...  
Keyword(s):  
Little Ice Age ◽  
Decadal Variability ◽  
Late Quaternary ◽  
Walker Circulation ◽  
Rapid Expansion ◽  
Ice Age ◽  
Ecosystem Structure ◽  
Ocean Biogeochemistry ◽  
Ocean Ecosystem ◽  
Abrupt Shifts

Abstract. Climate and ocean ecosystem variability has been well recognized during the twentieth century but it is unclear if modern ocean biogeochemistry is susceptible to the large, abrupt shifts that characterized the Late Quaternary. Time series from marine sediments off Peru show an abrupt centennial-scale biogeochemical regime shift in the early nineteenth century, of much greater magnitude and duration than present day multi-decadal variability. A rapid expansion of the subsurface nutrient-rich, oxygen-depleted waters resulted in the present-day higher biological productivity, including pelagic fish. The shift was likely driven by a northward migration of the Intertropical Convergence Zone and the South Pacific Subtropical High to their present day locations, coupled with a strengthening of Walker circulation, towards the end of the Little Ice Age. These findings reveal the potential for large reorganizations in tropical Pacific climate with immediate effects on ocean biogeochemical cycling and ecosystem structure.

scholarly journals Absence of Ship Rat Rattus rattus, and Norway Rat Rattus norvegicus, on Ouvea (Loyalty Islands, New Caledonia): consequences for conservation

1995 ◽  
Vol 2 (4) ◽  
pp. 390 ◽  
Author(s):  
Olivier Robinet ◽  
Michel Salas
Keyword(s):  
Success Rate ◽  
New Caledonia ◽  
Action Plan ◽  
Rattus Rattus ◽  
Indirect Evidence ◽  
Barn Owl ◽  
Norway Rat ◽  
Crop Fields ◽  
The Pacific ◽  
Ship Rat

A rat trapping campaign was conducted from July to December 1994 on Ouvea in the Loyalty Islands, New Caledonia. Locations of rat traps took into account different geographic sectors (North, Centre, South and Islets) and different habitats (forest, crop fields, coconut plantations, houses). The campaign encompassed a total of 1 363 trap nights and autopsy data were collected on rodents that were captured. Vertebrate remains from Barn Owl roosts were also collected and examined to determine which rat species were present. For the whole campaign the corrected trap success rate was 9.5 rodents per 100 trap nights. No significant variations in the trap success rate were observed in relation to geographic sector or habitat. Ninety-eight rodents were captured and 64 identified: six Mus musculus and 58 Rattus exulans. No Rattus rattus and no R. norvegicus were caught. Similarly, the only species identified from material found in Barn Owl roosts were M. musculus and R. exulans. Observation of the fauna and environment on Ouvea provided some indirect evidence to confirm the absence of both R. rattusand R. norvegicus. The history and geographical characteristics of Ouvea, and certainly chance, could explain the fact that these two species never reached the island. With regard to rat species, Ouvea's situation is remarkable and unique in the Pacific for inhabited islands of comparable size and level of development. Considering the dramatic and well known effects resulting from the introduction of rat species such as R. rattus and R. norvegicus on small Pacific Island environments, the authors have alerted local authorities and the population of Ouvea, and have proposed initial measures as part of an action plan.

Late Quaternary Vegetational Changes in a Marsh Forest in Southeastern Brazil with Comments on Prehistoric Human Occupation

Radiocarbon ◽  
2015 ◽  
Vol 57 (5) ◽  
pp. 737-753 ◽  
Author(s):  
Walter Mareschi Bissa ◽  
Mauro B de Toledo
Keyword(s):  
Sediment Core ◽  
Environmental Changes ◽  
Human Impacts ◽  
Late Quaternary ◽  
Southeastern Brazil ◽  
Pollen Record ◽  
Important Indicator ◽  
Climate Conditions ◽  
Ams Radiocarbon Dating ◽  
Se Brazil

This article presents a palynological study carried out on a sediment core from a peat deposit in Serra de Botucatu, in SÃo Paulo State, southeastern Brazilian Plateau. This region has been covered by grassland vegetation and forest patches throughout the recorded period. AMS radiocarbon dating plus palynological analysis of 27 samples from the sediment core allowed the recognition of several environmental changes that took place during the last 33,000 yr recorded in the core. The relationship between sedimentation rates and changes in the abundance of plants recognized through their pollen record, particularly a few important indicator species, provided the paleoenvironmental history for the Serra de Botucatu region, allowing the identification of changes in climate conditions and comparison with other regions in Brazil. One of the most remarkable features of this record is the cold and humid conditions during the Last Glacial Maximum, which diverges from previous interpretations for southeastern and southern Brazil but is in good agreement with paleoclimatic data from trace elements from cave stalagmites in SE Brazil. No indications of human impacts on the vegetation were found in this record.

scholarly journals Efficacy of Germinated Cereals as Bait Carrier for Zinc Phosphide and Bromadiolone against Field and Commensal Rodent Pests: A Laboratory Evaluation

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
P. Sakthivel ◽  
P. Neelanarayanan
Keyword(s):  
Pearl Millet ◽  
Finger Millet ◽  
Rattus Rattus ◽  
Zinc Phosphide ◽  
Field Conditions ◽  
Laboratory Evaluation ◽  
Toxicity Tests ◽  
Mus Booduga ◽  
Bandicota Bengalensis ◽  
Choice Tests

Both sexes of rodent pests such as Bandicota bengalensis, Millardia meltada, Mus booduga, and Rattus rattus were subjected to toxicity tests (acute rodenticide: 1.5% and 2% zinc phosphide and chronic rodenticide: bromadiolone (0.005%), under no-choice and choice tests) by using their preferred germinated cereals, namely, paddy, pearl millet, and finger millet, as bait base, individually. The results indicated that the poison baits in the germinated cereals induced all the chosen four species of rodent pests to consume greater quantities of bait perhaps due to the bait carrier’s palatability and texture. Besides these, the chosen three germinated cereals proved themselves that they are also capable of acting as suitable bait base for both selected rodenticides in bringing maximum mortality among the tested rodent pests under both no-choice and choice tests. Therefore, these germinated cereals may be recommended as a bait carrier for both zinc phosphide (2%) and bromadiolone (0.005%) poisons for the control of all these four species of rodent pests under field conditions. However, this requires field based trials with rodenticides for making a final recommendation.

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