scholarly journals Quality or quantity: small-scale patch structure affects patterns of biodiversity in a sublittoral blue mussel community

2011 ◽  
Vol 12 (3) ◽  
pp. 261-270 ◽  
Author(s):  
M Koivisto ◽  
M Westerbom ◽  
A Arnkil
2021 ◽  
Vol 168 (3) ◽  
Author(s):  
Rosyta Andriana ◽  
Friederike G. Engel ◽  
Joao B. Gusmao ◽  
Britas Klemens Eriksson

AbstractMigrating diatoms are microscopic ecosystem engineering organisms that have functional consequences on the seascape scale by significantly contributing to the microphytobenthos biofilm. The microphytobenthos biofilm is a thin photosynthesising layer that covers the sediment on intertidal flats. It fuels the food web, increases sediment stability, and enhances the deposition of particles, providing ecosystem services to coastal communities. Here we tested the effect of another ecosystem engineering habitat, intertidal blue mussel reefs, on the composition and properties of migrating diatom communities. Small-scale reefs constructed in the intertidal mimicked and reinforced the natural pattern in diatom community composition and function that we documented in the field. The field experiment adding small reefs to the intertidal ran from 30 April to 10 June 2015 and the field samples were collected around a natural blue mussel bed on the same tidal flat on 7 October 2015 (N 53.489°, E 6.230°). Both the constructed small-scale reefs and the natural reef changed the community composition of diatoms in the biofilm by promoting higher numbers of smaller-sized cells and species. Small diatoms have higher growth and gross photosynthesis rates, indicating that this explains the higher production and chlorophyll-a concentration of the biofilm measured on natural intertidal shellfish reefs. Our results showed that shellfish reefs have a large impact on biofilm functioning. However, biofilms are also fuel for the shellfish, indicating that the two very different ecosystem engineers may facilitate coexistence on tidal flats through a positive feedback loop.


Ecology ◽  
1995 ◽  
Vol 76 (4) ◽  
pp. 1195-1205 ◽  
Author(s):  
E. M. Steinauer ◽  
S. L. Collins

2021 ◽  
Vol 8 ◽  
Author(s):  
Julia Meyer ◽  
Ingrid Kröncke ◽  
Alexander Bartholomä ◽  
Mathias Heckroth ◽  
Gregor Scheiffarth

The cockle Cerastoderma edule is one of the most common macrofauna species in the Wadden Sea areas of the North Sea. Cockle population dynamics are influenced by various abiotic and biotic factors such as temperature, food availability, and inter- and intraspecific competition. Cockles play an important role in the food web of the Wadden Sea, for instance, large shellfish-eating birds, such as oystercatchers and common eiders, use the cockle C. edule and the blue mussel Mytilus edulis as a main diet component. However, the populations of shellfish-eating bird species have been declining dramatically across the Wadden Sea since the beginning of the 21st century. While there are detailed monitoring programs in blue mussels due to commercial interests, little information is known about the stocks and long-term dynamics of cockles in the German Wadden Sea. To fill this gap, in 2005 a local conservation society (“Der Mellumrat e.V.”) initiated a study to sample cockles at one transect per year south of the island of Mellum, which was extended by 5 more transects in 2011. In addition to the spatial analysis, we analyzed the long-term variability in cockle population dynamics. Min/max autocorrelation factor analysis (MAFA) revealed a decline in cockle abundance, while no clear length trends were found. Canonical and spearman correlation analyses exposed significant correlations between cockle abundance and length and chlorophyll a, mussel bank area as well as oystercatcher and common eider populations. This study clearly shows that there is an urgent need for comprehensive time series of cockle data to analyze and explain ecological long-term changes in cockle population dynamics in relation to environmental changes and to point out how parts of the Wadden Sea food web, such as shellfish-eating birds are affected by these changes.


2010 ◽  
Vol 135 (1-2) ◽  
pp. 34-41 ◽  
Author(s):  
François Gillet ◽  
Florian Kohler ◽  
Charlotte Vandenberghe ◽  
Alexandre Buttler

2021 ◽  
Author(s):  
Liam Butler ◽  
Roy Sanderson

Aims Vegetation sampling typically involves the use of quadrats, often 1m2, to estimate species cover-abundance. Such surveys do not generally record small-scale vegetation patch structure at sub-quadrat scales, for example 10 cm2. Here we test a simple method to quantify patch structure that complements conventional techniques. We compare the two methods, and analyse metrics derived from small-scale patch surveys with environment / management data. Location Northumberland, United Kingdom Methods We recorded cover-abundance of all species in an upland moor with 1m2 quadrats. These were divided into 100 'sub-quadrats', 10 x 10 cm, and the dominant and subdominant species identified. Patch metrics (number, area and shape) for individual species recorded as dominant or subdominant in the sub-quadrat survey were analysed using multivariate generalised linear models with environmental and management data. Sub-quadrat data were also aggregated for each quadrat, to create species composition data. The two sets of compositional data, from whole-quadrat and sub-quadrat aggregations, were compared via Procrustes rotation of ordination scores. Results Patch number, area and shape for dominant and subdominant species were all significantly affected by soil pH, soil water content, slope and elevation. Effects of proximity to sheep tracks and drainage ditches were less consistent amongst species. Ordinations of vegetation data from conventional and sub-quadrats were similar, with significant Procrustes R-squared of 67% and 70% for dominant and subdominant species respectively. Conclusions Sub-quadrat surveys can easily be used to complement existing whole-quadrat surveys at little cost in time or resources. Their patch metrics can provide additional insights into the environmental and management drivers that may affect the growth of individual plants or clumps, potentially in relation to plant traits, and thus alter the overall community composition. The methods we describe can readily be adapted to other sizes of quadrats and sub-quadrats in a wide range of vegetation communities.


2019 ◽  
Vol 42 ◽  
Author(s):  
William Buckner ◽  
Luke Glowacki

Abstract De Dreu and Gross predict that attackers will have more difficulty winning conflicts than defenders. As their analysis is presumed to capture the dynamics of decentralized conflict, we consider how their framework compares with ethnographic evidence from small-scale societies, as well as chimpanzee patterns of intergroup conflict. In these contexts, attackers have significantly more success in conflict than predicted by De Dreu and Gross's model. We discuss the possible reasons for this disparity.


2000 ◽  
Vol 179 ◽  
pp. 403-406
Author(s):  
M. Karovska ◽  
B. Wood ◽  
J. Chen ◽  
J. Cook ◽  
R. Howard

AbstractWe applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.


Author(s):  
CE Bracker ◽  
P. K. Hansma

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.


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