scholarly journals Evidence from South Africa for a protracted end-Permian extinction on land

2021 ◽  
Vol 118 (17) ◽  
pp. e2017045118
Author(s):  
Pia A. Viglietti ◽  
Roger B. J. Benson ◽  
Roger M. H. Smith ◽  
Jennifer Botha ◽  
Christian F. Kammerer ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Terrestrial Ecosystems ◽  
Faunal Assemblage ◽  
Karoo Basin ◽  
Extinction Rates ◽  
Occurrence Data ◽  
Permian Extinction ◽  
Assemblage Zone ◽  
Long Term Trend

Earth’s largest biotic crisis occurred during the Permo–Triassic Transition (PTT). On land, this event witnessed a turnover from synapsid- to archosauromorph-dominated assemblages and a restructuring of terrestrial ecosystems. However, understanding extinction patterns has been limited by a lack of high-precision fossil occurrence data to resolve events on submillion-year timescales. We analyzed a unique database of 588 fossil tetrapod specimens from South Africa’s Karoo Basin, spanning ∼4 My, and 13 stratigraphic bin intervals averaging 300,000 y each. Using sample-standardized methods, we characterized faunal assemblage dynamics during the PTT. High regional extinction rates occurred through a protracted interval of ∼1 Ma, initially co-occurring with low origination rates. This resulted in declining diversity up to the acme of extinction near the Daptocephalus–Lystrosaurus declivis Assemblage Zone boundary. Regional origination rates increased abruptly above this boundary, co-occurring with high extinction rates to drive rapid turnover and an assemblage of short-lived species symptomatic of ecosystem instability. The “disaster taxon” Lystrosaurus shows a long-term trend of increasing abundance initiated in the latest Permian. Lystrosaurus comprised 54% of all specimens by the onset of mass extinction and 70% in the extinction aftermath. This early Lystrosaurus abundance suggests its expansion was facilitated by environmental changes rather than by ecological opportunity following the extinctions of other species as commonly assumed for disaster taxa. Our findings conservatively place the Karoo extinction interval closer in time, but not coeval with, the more rapid marine event and reveal key differences between the PTT extinctions on land and in the oceans.

scholarly journals Long-Term Adaptation of Acidophilic Archaeal Ammonia Oxidisers Following Different Soil Fertilisation Histories

2021 ◽  
Author(s):  
Jun Zhao ◽  
Baozhan Wang ◽  
Xue Zhou ◽  
Mohammad Saiful Alam ◽  
Jianbo Fan ◽  
...  
Keyword(s):  
Community Composition ◽  
High Throughput Sequencing ◽  
Environmental Changes ◽  
Agricultural Soils ◽  
Terrestrial Ecosystems ◽  
Low Ph ◽  
Ph Change ◽  
Monooxygenase Gene ◽  
Ammonia Oxidising Archaea

AbstractAmmonia oxidising archaea (AOA) are ecologically important nitrifiers in acidic agricultural soils. Two AOA phylogenetic clades, belonging to order-level lineages of Nitrososphaerales (clade C11; also classified as NS-Gamma-2.3.2) and family-level lineage of Candidatus Nitrosotaleaceae (clade C14; NT-Alpha-1.1.1), usually dominate AOA population in low pH soils. This study aimed to investigate the effect of different fertilisation histories on community composition and activity of acidophilic AOA in soils. High-throughput sequencing of ammonia monooxygenase gene (amoA) was performed on six low pH agricultural plots originating from the same soil but amended with different types of fertilisers for over 20 years and nitrification rates in those soils were measured. In these fertilised acidic soils, nitrification was likely dominated by Nitrososphaerales AOA and ammonia-oxidising bacteria, while Ca. Nitrosotaleaceae AOA activity was non-significant. Within Nitrososphaerales AOA, community composition differed based on the fertilisation history, with Nitrososphaerales C11 only representing a low proportion of the community. This study revealed that long-term soil fertilisation selects for different acidophilic nitrifier communities, potentially through soil pH change or through direct effect of nitrogen, potassium and phosphorus. Comparative community composition among the differently fertilised soils also highlighted the existence of AOA phylotypes with different levels of stability to environmental changes, contributing to the understanding of high AOA diversity maintenance in terrestrial ecosystems.

TESTING THE DAPTOCEPHALUS AND LYSTROSAURUS ASSEMBLAGE ZONES IN A LITHOSTRATOGRAPHIC, MAGNETOSTRATIGRAPHIC, AND PALYNOLOGICAL FRAMEWORK IN THE FREE STATE, SOUTH AFRICA

Palaios ◽  
2019 ◽  
Vol 34 (11) ◽  
pp. 542-561 ◽  
Author(s):  
ROBERT A. GASTALDO ◽  
JOHANN NEVELING ◽  
JOHN W. GEISSMAN ◽  
CINDY V. LOOY
Keyword(s):  
Terrestrial Ecosystems ◽  
Free State ◽  
Eastern Cape ◽  
Zone Boundary ◽  
Data Set ◽  
Karoo Basin ◽  
Stratigraphic Position ◽  
Marine Realm ◽  
Normal Polarity ◽  
Assemblage Zone

ABSTRACT The vertebrate-fossil record in the Karoo Basin has served as the accepted model for how terrestrial ecosystems responded to the end-Permian extinction event. A database of several hundred specimens, placed into generalized stratigraphies, has formed the basis of a step-wise extinction scenario interpreted by other workers as spanning the upper Daptocephalus (=Dicynodon) to Lystrosaurus Assemblage Zones (AZ). Seventy-three percent of specimens used to construct the published model originate from three farms in the Free State: Bethel, Heldenmoed, and Donald 207 (Fairydale). The current contribution empirically tests: (1) the stratigraphic resolution of the vertebrate record on these farms; (2) whether a sharp boundary exists that delimits the vertebrate assemblage zones in these classic localities; and (3) if the Lystrosaurus AZ is of early Triassic age. We have used a multi-disciplinary approach, combining lithostratigraphy, magnetostratigraphy, vertebrate biostratigraphy, and palynology, to test these long-held assumptions. Previously reported vertebrate-collection sites have been physically placed into a litho- and magnetostratigraphic framework on the Bethel and Heldenmoed farms. The reported assemblage-zone boundary is used as the datum against which the stratigraphic position of vertebrates is compared and a preliminary magnetostratigraphy constructed. We find specimens of the Daptocephalus AZ originate in the Lystrosaurus AZ (as currently defined) and vice versa, and discrepancies between reported and field-checked stratigraphic positions below or above the assemblage-zone boundary often exceed 30 m. Hence, the utility of the data set in defining a sharp or abrupt biozone boundary is questionable. We further demonstrate the presence of a stratigraphically thick reverse polarity magnetozone that encompasses the reported assemblage-zone boundary, implying that these rocks are not correlative with the end-Permian event, which is reported to lie in a normal polarity chron. A latest Permian age is supported by palynological data from the Lystrosaurus AZ on the Donald 207 (Fairydale) farm, with equivalence to Australian (APP602) and Eastern Cape Province assemblages. We conclude that the turnover from the Daptocephalus to Lystrosaurus Assemblage Zones is more protracted than envisioned, it is not coincident with the end-Permian event as recognized in the marine realm, and little evidence exists in support of a three-phased extinction model based on vertebrate assemblages in the Karoo Basin.

scholarly journals Evolutionary rates of mid-Permian tetrapods from South Africa and the role of temporal resolution in turnover reconstruction

Paleobiology ◽  
2018 ◽  
Vol 44 (3) ◽  
pp. 347-367 ◽  
Author(s):  
Michael O. Day ◽  
Roger B. J. Benson ◽  
Christian F. Kammerer ◽  
Bruce S. Rubidge
Keyword(s):  
South Africa ◽  
Species Richness ◽  
High Resolution ◽  
Strong Support ◽  
Data Set ◽  
Terrestrial Vertebrates ◽  
Karoo Basin ◽  
Extinction Rates ◽  
Assemblage Zone ◽  
Important Time

AbstractThe Main Karoo Basin of South Africa contains a near-continuous sequence of continental deposition spanning ~80 Myr from the mid-Permian to the Early Jurassic. The terrestrial vertebrates of this sequence provide a high-resolution stratigraphic record of regional origination and extinction, especially for the mid–late Permian. Until now, data have only been surveyed at coarse stratigraphic resolution using methods that are biased by nonuniform sampling rates, limiting our understanding of the dynamics of diversification through this important time period. Here, we apply robust methods (gap-filler and modified gap-filler rates) for the inference of patterns of species richness, origination rates, and extinction rates to a subset of 1321 reliably-identified fossil occurrences resolved to approximately 50 m stratigraphic intervals. This data set provides an approximate time resolution of 0.3–0.6 Myr and shows that extinction rates increased considerably in the upper 100 m of the mid-Permian Abrahamskraal Formation, corresponding to the latest part of theTapinocephalusAssemblage Zone (AZ). Origination rates were only weakly elevated in the same interval and were not sufficient to compensate for these extinctions. Subsampled species richness estimates for the lower part of the overlying Teekloof Formation (corresponding to thePristerognathusandTropidostomaAZs) are low, showing that species richness remained low for at least 1.5–3 million years after the main extinction pulse. A high unevenness of the taxon abundance–frequency distribution, which is classically associated with trophically unstable postextinction faunas, in fact developed shortly before the acme of elevated extinction rates due to the appearance and proliferation of the dicynodontDiictodon. Our findings provide strong support for a Capitanian (“end-Guadalupian”) extinction event among terrestrial vertebrates and suggest that further high-resolution quantitative studies may help resolve the lack of consensus among paleobiologists regarding this event.

scholarly journals A case of long-term herbivory: specialized feeding trace on Parrotia (Hamamelidaceae) plant species

2020 ◽  
Vol 7 (10) ◽  
pp. 201449
Author(s):  
Benjamin Adroit ◽  
Xin Zhuang ◽  
Torsten Wappler ◽  
Jean-Frederic Terral ◽  
Bo Wang
Keyword(s):  
Western Europe ◽  
Environmental Changes ◽  
Terrestrial Ecosystems ◽  
Insect Damage ◽  
Ecosystem Structure ◽  
Biogeographic History ◽  
Fossil Leaves ◽  
Continuous Presence ◽  
Insect Interactions

Interactions between plants and insects evolved during millions of years of coevolution and maintain the trophic balance of terrestrial ecosystems. Documenting insect damage types (DT) on fossil leaves is essential for understanding the evolution of plant–insect interactions and for understanding the effects of major environmental changes on ecosystem structure. However, research focusing on palaeoherbivory is still sparse and only a tiny fraction of fossil leaf collections have been analysed. This study documents a type of insect damage found exclusively on the leaves of Parrotia species (Hamamelidaceae). This DT was identified on Parrotia leaves from Willershausen (Germany, Pliocene) and from Shanwang (China, Miocene) and on their respective endemic modern relatives: Parrotia perisca in the Hyrcanian forests (Iran) and Parrotia subaequalis in the Yixing forest (China). Our study demonstrates that this insect DT persisted over at least 15 Myr spanning eastern Asia to western Europe. Against expectations, more examples of this type of herbivory were identified on the fossil leaves than on the modern examples. This mismatch may suggest a decline of this specialized plant–insect interaction owing to the contraction of Parrotia populations in Eurasia during the late Cenozoic. However, the continuous presence of this DT demonstrates a robust and long-term plant–herbivore association, and provides new evidence for a shared biogeographic history of the two host plants.

NAEP Trends: Main NAEP vs. Long-Term Trend

2010 ◽  
Author(s):  
Albert E. Beaton ◽  
James R. Chromy
Keyword(s):  
Term Trend ◽  
Long Term Trend

Designing a CRM Framework for online & offline sports footwear retailers

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Rodrigo Cueva ◽  
Guillem Rufian ◽  
Maria Gabriela Valdes
Keyword(s):  
Environmental Changes ◽  
Customer Relationship ◽  
Business Strategies ◽  
Economic Sectors ◽  
Running Shoes ◽  
Brick And Mortar ◽  
Key Factor ◽  
On Line ◽  
The Impact

The use of Customer Relationship Managers to foster customers loyalty has become one of the most common business strategies in the past years.  However, CRM solutions do not fill the abundance of happily ever-after relationships that business needs, and each client’s perception is different in the buying process.  Therefore, the experience must be precise, in order to extend the loyalty period of a customer as much as possible. One of the economic sectors in which CRM’s have improved this experience is retailing, where the personalized attention to the customer is a key factor.  However, brick and mortar experiences are not enough to be aware in how environmental changes could affect the industry trends in the long term.  A base unified theoretical framework must be taken into consideration, in order to develop an adaptable model for constructing or implementing CRMs into companies. Thanks to this approximation, the information is complemented, and the outcome will increment the quality in any Marketing/Sales initiative. The goal of this article is to explore the different factors grouped by three main domains within the impact of service quality, from a consumer’s perspective, in both on-line and off-line retailing sector.  Secondly, we plan to go a step further and extract base guidelines about previous analysis for designing CRM’s solutions focused on the loyalty of the customers for a specific retailing sector and its product: Sports Running Shoes.

Institutionalizing the Liberal Creed

2017 ◽  
Author(s):  
Ronen Mandelkern
Keyword(s):  
Political Influence ◽  
Institutional Entrepreneurship ◽  
Political Decision ◽  
Economic Liberalism ◽  
Market Economic ◽  
Ministry Of Finance ◽  
Political Entrepreneurs ◽  
Long Term Trend ◽  
Political Decision Making

This chapter analyzes the role Israeli economists have played as purveyors of pro-market economic ideas and political entrepreneurs of economic liberalization in Israel. Israeli economists were strongly committed to economic liberalism already in the 1950s, but they were lacking decisive political influence. Two mechanisms increased their power over policy. First, long-term institutional changes gradually eroded “political” decision-making mechanism and opened the way to greater involvement of professional economists. This long-term trend was joined and reinforced by economists’ institutional entrepreneurship at the height of the 1980s economic crisis, when they initiated changes of macroeconomic governance. These changes enhanced the political power of the Ministry of Finance and the Bank of Israel and supported the institutionalization of neoliberalism in Israel.

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.

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