scholarly journals MURAWY PIASKOWE ZE ZWIĄZKU SILENO CONICAE-CERASTION SEMIDECANDRI KORNECK 1974 NA TERENIE KAMPUSU UAM MORASKO W POZNANIU

1970 ◽  
Vol 65 ◽  
pp. 39-76
Author(s):  
Andrzej Brzeg ◽  
Tomasz Szygendowski
Keyword(s):  
Environmental Gradients ◽  
Field Studies ◽  
Cca Ordination ◽  
Ordination Methods ◽  
Table Analysis ◽  
Adam Mickiewicz

Field studies on anthropogenic psammophilous swards of the Sileno conicae-Cerastion semidecandri alliance were carried out in the years 2015–2016 in the area of the Adam Mickiewicz University Morasko campus in Poznań, Poland. As a result of a classical table analysis of phytosociological data, five associations were distinguished. The relevés have been arranged with the use of PCA and CCA ordination methods to study the overall variability of the examined communities and their position along some environmental gradients. In the paper, issues concerning successional dynamics and the synsystematical position of swards of the studied type, are also raised.

scholarly journals Mixotrophy in nanoflagellates across environmental gradients in the ocean

2019 ◽  
Vol 116 (13) ◽  
pp. 6211-6220 ◽  
Author(s):  
Kyle F. Edwards
Keyword(s):  
Competitive Ability ◽  
Resource Competition ◽  
Environmental Gradients ◽  
Light Availability ◽  
Field Studies ◽  
Heterotrophic Nanoflagellates ◽  
Coastal Environments ◽  
Unicellular Eukaryotes ◽  
Theoretical Predictions ◽  
Trophic Strategy

Mixotrophy, the combination of autotrophic and heterotrophic nutrition, is a common trophic strategy among unicellular eukaryotes in the ocean. There are a number of hypotheses about the conditions that select for mixotrophy, and field studies have documented the prevalence of mixotrophy in a range of environments. However, there is currently little evidence for how mixotrophy varies across environmental gradients, and whether empirical patterns support theoretical predictions. Here I synthesize experiments that have quantified the abundance of phototrophic, mixotrophic, and heterotrophic nanoflagellates, to ask whether there are broad patterns in the prevalence of mixotrophy (relative to pure autotrophy and heterotrophy), and to ask whether observed patterns are consistent with a trait-based model of trophic strategies. The data suggest that mixotrophs increase in abundance at lower latitudes, while autotrophs and heterotrophs do not, and that this may be driven by increased light availability. Both mixotrophs and autotrophs increase greatly in productive coastal environments, while heterotrophs increase only slightly. These patterns are consistent with a model of resource competition in which nutrients and carbon can both limit growth and mixotrophs experience a trade-off in allocating biomass to phagotrophy vs. autotrophic functions. Importantly, mixotrophy is selected for under a range of conditions even when mixotrophs experience a penalty for using a generalist trophic strategy, due to the synergy between photosynthetically derived carbon and prey-derived nutrients. For this reason mixotrophy is favored relative to specialist strategies by increased irradiance, while at the same time increased nutrient supply increases the competitive ability of mixotrophs against heterotrophs.

scholarly journals Density of intertidal barnacles along their full elevational range of distribution conforms to the abundant-centre hypothesis

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6719 ◽  
Author(s):  
Ricardo A. Scrosati ◽  
Matthew J. Freeman
Keyword(s):  
Vertical Distribution ◽  
Environmental Gradients ◽  
Field Studies ◽  
Distribution Range ◽  
Sampling Effort ◽  
Predictive Tool ◽  
Distribution Centre ◽  
Substrate Properties ◽  
Elevational Range ◽  
High Elevations

The abundant-centre hypothesis (ACH) predicts that the density of a species should peak at its distribution centre and decrease similarly towards distribution margins. The ACH has been deduced from a theory that postulates that environmental conditions should be most favourable for a species at the centre of its distribution. This idealised density pattern, however, has been supported by limited field studies, as natural patterns are often more complex. It is thus of interest to examine under what conditions compliance with the ACH could be favoured. Such conditions could be smooth environmental gradients with limited habitat patchiness throughout the distribution range of a species. Thus, we tested the ACH by measuring the density of an intertidal barnacle (Semibalanus balanoides) across its full vertical distribution range (from low to high elevations) on a rocky shore with similar substrate properties across elevations. To do a reliable test, we surveyed eight elevation zones applying an equal sampling effort in each zone. Average barnacle density conformed to the ACH, as it peaked at the middle of the vertical distribution range of this species. The same underlying theory predicts a similar unimodal pattern for maximum body size, but this trait was decoupled from density, as maximum barnacle size increased from low to high elevations. Overall, although the ACH is not a universal predictive tool as once envisioned, it may predict some cases well, as shown by this study. Therefore, the ACH should not be discarded completely, and its domain of application should be further evaluated.

Community ecology’s roots

2019 ◽  
pp. 1-8
Author(s):  
Gary G. Mittelbach ◽  
Brian J. McGill
Keyword(s):  
Ecological Niche ◽  
Environmental Gradients ◽  
Field Studies ◽  
Community Diversity ◽  
Exclusion Principle ◽  
Limiting Similarity ◽  
Competitive Exclusion Principle ◽  
Animal Populations ◽  
New Directions ◽  
Natural Communities

This chapter introduces the field of community ecology and reviews its history. The first community ecologists were botanists who noted what appeared to be repeated associations between plant species along environmental gradients. From these studies arose the concept of ecological succession. Laboratory and field studies of animal populations generated the important concepts of density-dependence, the competitive exclusion principle, and the ecological niche. The idea that interspecific competition limited the membership of communities to certain kinds of species produced the historically important theory of limiting similarity, which specified how different species must be in their niche in order to coexist. This theory appeared to provide a framework for predicting both the number and types of species found in natural communities, however, it failed to deliver on its promise. The failure of simple competition-based models to explain community diversity led to important new directions that continue to influence how ecologists study communities today.

scholarly journals Dung beetle–mammal associations: methods, research trends and future directions

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182002 ◽  
Author(s):  
Elizabeth H. Raine ◽  
Eleanor M. Slade
Keyword(s):  
Ecosystem Functioning ◽  
Environmental Gradients ◽  
Association Studies ◽  
Terrestrial Ecosystems ◽  
Dung Beetle ◽  
Field Studies ◽  
Dung Beetles ◽  
Mammal Species ◽  
Wide Range ◽  
Species Richness And Abundance

Dung beetles are increasingly used as a study taxon—both as bioindicators of environmental change, and as a model system for exploring ecosystem functioning. The advantages of this focal taxon approach are many; dung beetles are abundant in a wide range of terrestrial ecosystems, speciose, straightforward to sample, respond to environmental gradients and can be easily manipulated to explore species-functioning relationships. However, there remain large gaps in our understanding of the relationship between dung beetles and the mammals they rely on for dung. Here we review the literature, showing that despite an increase in the study of dung beetles linked to ecosystem functioning and to habitat and land use change, there has been little research into their associations with mammals. We summarize the methods and findings from dung beetle–mammal association studies to date, revealing that although empirical field studies of dung beetles rarely include mammal data, those that do, indicate mammal species presence and composition has a large impact on dung beetle species richness and abundance. We then review the methods used to carry out diet preference and ecosystem functioning studies, finding that despite the assumption that dung beetles are generalist feeders, there are few quantitative studies that directly address this. Together this suggests that conclusions about the effects of habitat change on dung beetles are based on incomplete knowledge. We provide recommendations for future work to identify the importance of considering mammal data for dung beetle distributions, composition and their contributions to ecosystem functioning; a critical step if dung beetles are to be used as a reliable bioindicator taxon.

Empty visual field studies: Some effects of corrective lenses, filters, and structure.

1964 ◽  
Author(s):  
Milton S. Katz ◽  
Paul A. Cirincione ◽  
William Metlay
Keyword(s):  
Visual Field ◽  
Field Studies

Vocal signaling among male northern elephant seals: Behavioral field studies of honesty vs. associative learning

2012 ◽  
Author(s):  
Colleen Reichmuth ◽  
Caroline Casey ◽  
Isabelle Charrier ◽  
Nicolas Mathevon ◽  
Brandon Southall
Keyword(s):  
Associative Learning ◽  
Field Studies ◽  
Elephant Seals ◽  
Northern Elephant Seals ◽  
Vocal Signaling

Penggunaan Media Pembelajaran Berbasis Android untuk Meningkatkan Hasil Belajar Kognitif Siswa

2019 ◽  
Vol 5 (2) ◽  
pp. 104-111
Author(s):  
Dian Puspita Eka Putri
Keyword(s):  
High School Students ◽  
Learning Outcomes ◽  
Multimedia Learning ◽  
Cognitive Learning ◽  
Field Studies ◽  
Research Subjects ◽  
School Students ◽  
Increase Student Achievement ◽  
Post Test ◽  
Test Result

This study aims to review  the effectiveness of using android-based multimedia learning  to improve achievement cognitive learning outcome of students. The research method is the analysis of field studies. The focus in this research is Multimedia which can influence cognitive learning outcomes of students. data obtained in this study from the literature and direct field observations. The research subjects were high school students in Yogyakarta. The result of analysis and discussion of research indicate that there is the influence of multimedia learning to increase student achievement, which is indicated by increasing post-test result  than before  not using multimedia learning. Posttest value is greater than pretest.

EMPIRICAL SUPPORT FOR THE POSSIBLE APPLICATION OF MODIFIED ELLENBERG INDICES TO THE STUDY OF ENVIRONMENTAL GRADIENTS ON DYNAMIC IRISH WETLANDS— EVIDENCE FROM SKEALOGHAN TURLOUGH, COUNTY MAYO

2011 ◽  
Vol 111 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Christopher D. Williams ◽  
Boudewijn Beltman ◽  
James Moran ◽  
Micheline Sheehy Skeffington ◽  
Michael J. Gormally
Keyword(s):  
Environmental Gradients ◽  
Empirical Support ◽  
County Mayo
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