Testing a relict distributional pattern of fen plant and terrestrial snail species at the Holocene scale: a null model approach

AbstractRecent studies showing bias in the measurement of density dependence have the potential to sow confusion in the field of ecology. We provide clarity by elucidating key conceptual and statistical errors with the null-model approach used in Detto et al. (2019). We show that neither their null model nor a more biologically-appropriate null model reproduces differences in density-dependent recruitment between forests, indicating that the latitudinal gradient in negative density dependence is not an artefact of statistical bias. Finally, we suggest a path forward that combines observational comparisons of density dependence in multiple fitness components across localities with mechanistic and geographically-replicated experiments.

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Preliminary malacological investigation on the loess profile at Zmajevac, Croatia

Open Geosciences ◽

10.2478/v10085-009-0045-0 ◽

2010 ◽

Vol 2 (1) ◽

Cited By ~ 7

Author(s):

David Molnár ◽

Júlia Hupuczi ◽

Lidija Galović ◽

Pál Sümegi

Keyword(s):

Initial Phase ◽

Middle Pleistocene ◽

Snail Species ◽

Terrestrial Snail ◽

Loess Profile

AbstractMore than 5 500 specimens of 37 terrestrial snail species were collected from a loess paleosol section at Zmajevac village, Croatia. The presence of Ena montana, Mastus bielzi, Cochlodina laminata, Macrogastra ventricosa, Clausilia pumila, Clausilia dubia, Pseudofusulus varians, Trichia unidentata and Trichia edentula species from the lower paleosol layer suggests that this malacological zone formed during the initial phase of a Middle Pleistocene interglacial cycle.

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Combined Stochastic and Deterministic Processes Drive Community Assembly of Anaerobic Microbiomes During Granule Flotation

Frontiers in Microbiology ◽

10.3389/fmicb.2021.666584 ◽

2021 ◽

Vol 12 ◽

Author(s):

Anna Christine Trego ◽

Paul G. McAteer ◽

Corine Nzeteu ◽

Therese Mahony ◽

Florence Abram ◽

...

Keyword(s):

Community Assembly ◽

Null Model ◽

Amplicon Sequencing ◽

Dairy Wastewater ◽

Rrna Gene ◽

Primary Mechanism ◽

Process Failure ◽

Deterministic Processes ◽

Process Disturbances ◽

Model Approach

Advances in null-model approaches have resulted in a deeper understanding of community assembly mechanisms for a variety of complex microbiomes. One under-explored application is assembly of communities from the built-environment, especially during process disturbances. Anaerobic digestion for biological wastewater treatment is often underpinned by retaining millions of active granular biofilm aggregates. Flotation of granules is a major problem, resulting in process failure. Anaerobic aggregates were sampled from three identical bioreactors treating dairy wastewater. Microbiome structure was analysed using qPCR and 16S rRNA gene amplicon sequencing from DNA and cDNA. A comprehensive null-model approach quantified assembly mechanisms of floating and settled communities. Significant differences in diversity were observed between floating and settled granules, in particular, we highlight the changing abundances of Methanosaeta and Lactococcus. Both stochastic and deterministic processes were important for community assembly. Homogeneous selection was the primary mechanism for all categories, but dispersal processes also contributed. The lottery model was used to identify clade-level competition driving community assembly. Lottery “winners” were identified with different winners between floating and settled groups. Some groups changed their winner status when flotation occurred. Spirochaetaceae, for example, was only a winner in settled biomass (cDNA-level) and lost its winner status during flotation. Alternatively, Arcobacter butzerli gained winner status during flotation. This analysis provides a deeper understanding of changes that occur during process instabilities and identified groups which may be washed out—an important consideration for process control.

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Are there multiple scaling regimes in Holocene temperature records?

Earth System Dynamics ◽

10.5194/esd-7-419-2016 ◽

2016 ◽

Vol 7 (2) ◽

pp. 419-439 ◽

Cited By ~ 9

Author(s):

Tine Nilsen ◽

Kristoffer Rypdal ◽

Hege-Beate Fredriksen

Keyword(s):

Radiative Forcing ◽

Ice Core ◽

Null Model ◽

Ice Cores ◽

Internal Variability ◽

Observation Data ◽

The Holocene ◽

Temperature Records ◽

Glacial Time ◽

Scale Break

Abstract. The concept of multiple scaling regimes in temperature time series is examined, with emphasis on the question whether or not a monoscaling model with one single scaling regime can be rejected from observation data from the Holocene. A model for internal variability with only one regime is simpler and allows more certain predictions on timescales of centuries when combined with existing knowledge of radiative forcing. Our analysis of spectra from stable isotope ratios from Greenland and Antarctica ice cores shows that a scale break around centennial timescales is evident for the last glacial period, but not for the Holocene. Spectra from a number of late Holocene multiproxy temperature reconstructions, and one from the entire Holocene, have also been analysed, without identifying a significant scale break. Our results indicate that a single-regime scaling climate noise, with some non-scaling fluctuations on a millennial timescale superposed, cannot be rejected as a null model for the Holocene climate. The scale break observed from the glacial time ice-core records is likely caused by the influence of Dansgaard–Oeschger events and teleconnections to the Southern Hemisphere on centennial timescales. From our analysis we conclude that the two-regime model is not sufficiently justified for the Holocene to be used for temperature prediction on centennial timescales.

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A glacial refugium and zoogeographic boundary in the Slovak eastern Carpathians

Quaternary Research ◽

10.1017/qua.2018.68 ◽

2018 ◽

Vol 91 (1) ◽

pp. 383-398 ◽

Cited By ~ 1

Author(s):

Lucie Juřičková ◽

Jitka Horáčková ◽

Anna Jansová ◽

Jiří Kovanda ◽

Ján Harčár ◽

...

Keyword(s):

Late Glacial ◽

Glacial Refugium ◽

Small Scale ◽

Snail Species ◽

The Holocene ◽

Eastern Carpathians ◽

Molluscan Fauna ◽

Fossil Records ◽

Glacial Periods ◽

First Time

AbstractAlthough the Carpathians in Europe have often been considered a glacial refugium for temperate plants, vertebrates, and molluscs, the fossil records, the only indisputable evidence surviving glacial periods, are as yet scarce. Moreover, the distribution of fossil records is uneven, and some areas have remained unstudied. We present here three molluscan successions from such an area—the border between the western and eastern Carpathians. This area is not only a geographic border but also a border between the oceanic and continental climate in Europe, and the molluscan fauna reflects this. We found a fluctuation of this zoogeographical border during the late glacial period and the Holocene for several snail species with their easternmost or westernmost distribution situated at this border. Such a fluctuation could reflect a small-scale shifting of climate character during the Holocene. For the first time, we recorded the fossil shells of three local endemics, Carpathica calophana, Petasina bielzi, and Perforatella dibothrion. We also found a fully developed woodland snail fauna radiocarbon dated to the Bølling period. This early occurrence of canopy forest snails indicates a possible eastern Carpathian glacial refugium for them, including local endemics, and may reflect a more moderate glacial impact on local biota than expected.

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