Geographic patterns of crayfish symbiont diversity persist over half a century despite seasonal fluctuations

2016 ◽  
Vol 22 (1) ◽  
pp. 9-18
Author(s):  
James Skelton ◽  
Robert P. Creed ◽  
Lukas Landler ◽  
Kevin M. Geyer ◽  
Bryan L. Brown
Keyword(s):  
Species Composition ◽  
Census Data ◽  
Mountain Lake ◽  
Ecological Processes ◽  
Spatial And Temporal Scales ◽  
Host Fidelity ◽  
Habitat Gradients ◽  
Geographic Patterns ◽  
The Stability ◽  
Species Occurrences

Abstract We analyzed historical data from 1961-1965 for species occurrences of branchiobdellidans and their crayfish hosts throughout the Mountain Lake Region of southwestern Virginia, USA to quantify geographic variability in species composition and identify patterns in host and symbiont diversity. We collected contemporary census data of branchiobdellidan assemblages from the same region in 2011-2014 for intra-annual variation in symbiont abundance and species composition. We compared historical and contemporary records to assess the stability of geographic patterns in symbiont diversity over decadal timescales. Branchiobdellidan assemblages followed a hump-shaped relationship with Strahler stream order. Much of the geographic variation in symbiont species composition was explained by host species composition, despite low host fidelity in branchiobdellidans. There were strong seasonal cycles in branchiobdellidan abundance and species composition. A comparison of historical and contemporary records revealed little change in species distributions over 50 years. Thus, branchiobdellidan species composition changes predictably along habitat gradients, tracks variation in host composition, is repeatable across decadal timescales, and follow strong cyclic seasonal changes in total and relative abundances. These results suggest that complex but deterministic ecological processes drive symbiont population dynamics at multiple spatial and temporal scales.

scholarly journals Temporal Stability and Biodiversity of Two Complex Antilisterial Cheese-Ripening Microbial Consortia

2003 ◽  
Vol 69 (7) ◽  
pp. 4012-4018 ◽  
Author(s):  
Ariel Maoz ◽  
Ralf Mayr ◽  
Siegfried Scherer
Keyword(s):  
Species Composition ◽  
Bacterial Species ◽  
Temporal Stability ◽  
Individual Characteristics ◽  
Microbial Consortia ◽  
Cheese Ripening ◽  
Safe Food ◽  
The Stability ◽  
The Individual ◽  
First Time

ABSTRACT The temporal stability and diversity of bacterial species composition as well as the antilisterial potential of two different, complex, and undefined microbial consortia from red-smear soft cheeses were investigated. Samples were collected twice, at 6-month intervals, from each of two food producers, and a total of 400 bacterial isolates were identified by Fourier-transform infrared spectroscopy and 16S ribosomal DNA sequence analysis. Coryneform bacteria represented the majority of the isolates, with certain species being predominant. In addition, Marinolactobacillus psychrotolerans, Halomonas venusta, Halomonas variabilis, Halomonas sp. (106 to 107 CFU per g of smear), and an unknown, gram-positive bacterium (107 to 108 CFU per g of smear) are described for the first time in such a consortium. The species composition of one consortium was quite stable over 6 months, but the other consortium revealed less diversity of coryneform species as well as less stability. While the first consortium had a stable, extraordinarily high antilisterial potential in situ, the antilisterial activity of the second consortium was lower and decreased with time. The cause for the antilisterial activity of the two consortia remained unknown but is not due to the secretion of soluble, inhibitory substances by the individual components of the consortium. Our data indicate that the stability over time and a potential antilisterial activity are individual characteristics of the ripening consortia which can be monitored and used for safe food production without artificial preservatives.

A Geographical Information System (GIS) study of Triassic vertebrate biochronology

2005 ◽  
Vol 142 (4) ◽  
pp. 327-354 ◽  
Author(s):  
E. J. RAYFIELD ◽  
P. M. BARRETT ◽  
R. A. McDONNELL ◽  
K. J. WILLIS
Keyword(s):  
Spatial Data ◽  
Geographical Information Systems ◽  
Western Europe ◽  
Temporal Distribution ◽  
Geographical Information ◽  
Late Triassic ◽  
Spatial And Temporal Scales ◽  
Potential Index ◽  
The Stability ◽  
Land Vertebrate

Geographical Information Systems (GIS) have been applied extensively to analyse spatial data relating to varied environmental issues, but have not so far been used to address biostratigraphical or macroevolutionary questions over extended spatial and temporal scales. Here, we use GIS techniques to test the stability, validity and utility of proposed Middle and Late Triassic ‘Land Vertebrate Faunachrons’ (LVFs), a global biostratigraphical framework based upon terrestrial/freshwater tetrapod occurrences. A database of tetrapod and megafloral localities was constructed for North America and Western Europe that also incorporated information on relevant palaeoenvironmental variables. This database was subjected to various spatial analysis techniques. Our GIS analysis found support at a global level for Eocyclotosaurus as an Anisian index taxon and probably Aetosaurus as a Norian indicator. Other tetrapod taxa are useful biostratigraphical/biochronological markers on a regional basis, such as Longosuchus and Doswellia for Late Carnian time. Other potential index fossils are hampered, however, by taxonomic instability (Mastodonsaurus, Metoposaurus, Typothorax, Paleorhinus, Pseudopalatus, Redondasaurus, Redondasuchus) and/or are not clearly restricted in temporal distribution (Paleorhinus, Angistorhinus, Stagonolepis, Metoposaurus and Rutiodon). This leads to instability in LVF diagnosis. We found only in the western Northern Hemisphere is there some evidence for an Anisian–Ladinian biochronological unit amalgamating the Perovkan and Berdyankian LVFs, and a possible late Carnian unit integrating the Otischalkian and Adamanian.Megaplants are generally not useful for biostratigraphical correlation in the Middle and Upper Triassic of the study area, but there is some evidence for a Carnian-age floral assemblage that corresponds to the combined Otischalkian and Adamanian LVFs. Environmental biases do not appear to strongly affect the spatial distribution of either the tetrapods or megaplants that have been proposed as index taxa in biostratigraphical schemes, though several examples of apparent environmental bias were detected by the analysis. Consequently, we argue that further revision and refinement of Middle and Late Triassic LVFs is needed before they can be used to support global or multi-regional biostratigraphical correlations. Caution should therefore be exercised when using the current scheme as a platform for macroevolutionary or palaeoecological hypotheses. Finally, this study demonstrates the potential of GIS as a powerful tool for tackling palaeontological questions over extended timescales.

scholarly journals Fishing effects on elasmobranchs from the Pacific Coast of Colombia

2016 ◽  
Vol 21 (1) ◽  
pp. 9 ◽  
Author(s):  
Andrés Felipe Navia ◽  
Paola Andrea Mejía-Falla
Keyword(s):  
Species Composition ◽  
Pacific Coast ◽  
Trophic Levels ◽  
Functional Level ◽  
The Pacific ◽  
The Mean ◽  
The Stability ◽  
Large Predators ◽  
Average Catch ◽  
Index Of Diversity

<p>During 1995, 2001, 2003, 2004 and 2007; we studied the temporal variation in the structure of the elasmobranch assemblage along the Colombian Pacific coast using: the community index of diversity, heterogeneity, equitability, species composition, average catch sizes, and mean trophic levels. A total of 1 711 specimens from 19 species<br />(7 sharks and 12 rays) were collected during the 90 trawling operations. The number of species captured varied between 7 (1995) and 12 (2007) demonstrating a trend towards an imbalance in the assemblage attributes. In 1995, the mean trophic level (TLm) of the assemblage was 3.60, but in 2007 it decreased to 3.55 when the functional level of large predators was absent (TL ≥ 4). These results suggest changes in species composition, structural attributes, and a reduction of the highest functional level. Alterations to the catch proportions were also found: i.e. a greater abundance of rays of lower trophic levels. This study suggests an effect of trawling on the stability of this tropical coastal ecosystem.</p>

scholarly journals Habitats and Diversity of Subterranean Macroscopic Freshwater Invertebrates: Main Gaps and Future Trends

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2170
Author(s):  
Elzbieta Dumnicka ◽  
Tanja Pipan ◽  
David Culver
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Habitat Size ◽  
Tropical Regions ◽  
High Productivity ◽  
Local Diversity ◽  
Geographic Patterns ◽  
Temperature Oscillations ◽  
Subterranean Species

Caves are the best studied aquatic subterranean habitat, but there is a wide variety of these habitats, ranging in depth below the surface and size of the spaces (pore or habitat size). Both factors are important in setting limits to species composition and richness. In addition to caves, among the most important shallow aquatic subterranean habitats are the hyporheal (underflow of rivers and streams), the hypotelminorheal (very superficial drainages with water exiting in seeps), epikarst, and calcrete aquifers. Although it is little studied, both body size and species composition in the different habitats is different. Because of high levels of endemism and difficulty in access, no subterranean habitats are well sampled, even caves. However, there are enough data for robust generalizations about some geographic patterns. Individual hotspot caves are concentrated in the Dinaric region of southern Europe, and overall, tropical regions have fewer obligate aquatic cave dwellers (stygobionts). In all subterranean aquatic habitats, regional diversity is much higher than local diversity, but local diversity (especially single cave diversity) may be a useful predictor of regional species richness. In Europe there is a ridge of high aquatic subterranean species richness basically extending east from the French–Spanish border. Its cause may be either high productivity or that long-term temperature oscillations are at a minimum. With increased collecting and analysis, global and continental trends should become clearer.

Environmental flow requirements in arid zone rivers – a case study from the Lake Eyre Basin, central Australia

2003 ◽  
Vol 48 (7) ◽  
pp. 65-72 ◽  
Author(s):  
J.F. Costelloe ◽  
J.T. Puckridge ◽  
J.R.W. Reid ◽  
J. Pritchard ◽  
P. Hudson ◽  
...  
Keyword(s):  
Arid Zone ◽  
Environmental Flow ◽  
Environmental Drivers ◽  
Ecological Processes ◽  
Discharge Data ◽  
Spatial And Temporal Scales ◽  
Biological Responses ◽  
Key Drivers ◽  
Real Flow

The ARIDFLO project takes a multi-disciplinary approach to the collection and analysis of data required to formulate appropriate environmental flow requirements for rivers in the Lake Eyre Basin. The key drivers of the ecological processes underpinning the health of these rivers are identified by modelling whole-of-ecosystem biological responses to hydrological events over a range of spatial and temporal scales. First, the hydrology of these poorly gauged (often ungauged) rivers needs to be modelled and validated to mimic real flow and inundation patterns at the catchment, reach and waterbody scale. Modelled and actual discharge data are then used to provide a suite of hydrological predictor variables which, in conjunction with other environmental variables, are used to model observed biotic responses. The key hydrologic and environmental drivers identified by the statistical models need to be taken into account when determining environmental flow requirements for these river systems. Further work is required to assess the predictive power of the models in the highly variable, complex systems of the Lake Eyre Basin rivers.

scholarly journals The results of the introduction of Juglans mandshurica Maxim. into the oak-woods of the Khopyor region

2018 ◽  
Vol 11 ◽  
pp. 00030
Author(s):  
Anastasia Ovcharenko ◽  
Alevtina Ovcharenko
Keyword(s):  
Species Composition ◽  
Environmental Conditions ◽  
Flood Plain ◽  
Distribution Area ◽  
Juglans Mandshurica ◽  
Ecological Functions ◽  
Natural Distribution ◽  
The Stability ◽  
Selection Of Species ◽  
Selection Of

An analysis of the results of the introduction of Juglans mandshurica Maxim. into the flood-plain oak-woods of the Khopyor is conducted. The total bioecological assessment and prospects of the introduction into the natural flood-plain oak-woods of the Middle Khopyor region for the enrichment of their species composition with the aim of enhancing the sustainability of these ecosystems and optimization of their ecological functions are given. The compliance of the environmental conditions of the growth of introduced stands in the middle reaches of the Khopyor River, original within the natural distribution area is found. Alongside with the identified typical directions of reduction in the indicators of the stability and productivity of this breed in introduced centres in comparison with the natural areas there detected trends in increasing the resistance of the species in the succeeding generations, as a result of clone variability, a selection of species with a high vital potential and adaptive capacity.

scholarly journals Learning, Host Fidelity, and the Stability of Host‐Parasitoid Communities

1999 ◽  
Vol 153 (3) ◽  
pp. 295-301 ◽  
Author(s):  
Alan Hastings ◽  
H. C. J. Godfray
Keyword(s):  
Host Fidelity ◽  
The Stability

scholarly journals Cyanobacteria bloom: selective filter for zooplankton?

2015 ◽  
Vol 75 (1) ◽  
pp. 165-174 ◽  
Author(s):  
NAST Mello ◽  
PM Maia-Barbosa
Keyword(s):  
Species Composition ◽  
Hydrological Cycle ◽  
Diversity Index ◽  
Zooplankton Community ◽  
Distribution Patterns ◽  
Distinct Species ◽  
Zooplankton Community Structure ◽  
Β Diversity ◽  
Cyanobacteria Blooms ◽  
The Stability

The Ibirité reservoir is an urban and eutrophic environment, with regular occurrences of cyanobacteria blooms. The reservoir is warm monomict and remains stratified most of the year, circulating in the dry season (winter). During the hydrological cycle of October/07 to October/08 there were four scenarios with different environmental conditions, which influenced the structure of the zooplankton community, as confirmed in a previous study. Changes in the zooplankton community structure between the scenarios were studied, aiming at analyzing the stability and persistence of this community. The Spearman’s coefficient of correlation was used to measure the stability; the persistence was evaluated through a cluster analysis and changes in community composition were estimated by the "temporal" β diversity index. Considering the distribution patterns of abundance, the community was stable only in the transition between scenarios 1 and 2 (n = 30, r = 0.71, p = 0.00001), when there were no cyanobacteria blooms. The persistence of zooplankton between the scenarios was low, showing a distinct species composition for each scenario. The highest variations in species composition, observed by the values of temporal β diversity index, were the transitions between scenarios 3-0 (1.45) and 0-1 (1.05), and the lowest variations occurred in the transition between scenarios 1-2 (0.57). The results suggest that the cyanobacteria blooms at Ibirité reservoir are be acting as "selective filters", and are, thus, disturbances with sufficient ability to change the structure of the zooplankton community. Keywords Urban Reservoir, zooplankton, bloom of cyanobacteria, stability, persistence.

scholarly journals Variation in Seagrass-Associated Macroinvertebrate Communities Along the Gulf Coast of Peninsular Florida: An Exploration of Patterns and Ecological Consequences

2021 ◽  
Vol 8 ◽  
Author(s):  
Savanna C. Barry ◽  
A. Challen Hyman ◽  
Charles A. Jacoby ◽  
Laura K. Reynolds ◽  
Michal Kowalewski ◽  
...  
Keyword(s):  
Species Composition ◽  
Gulf Coast ◽  
Single Species ◽  
Common Species ◽  
Phosphorus Concentration ◽  
Spatial Gradient ◽  
Macroinvertebrate Communities ◽  
Spatial And Temporal Scales ◽  
Seagrass Meadows ◽  
Estuarine Systems

Seagrasses form vast meadows of structurally complex habitat that support faunal communities with greater numbers of species and individuals than nearby unstructured habitats. The Gulf coast of peninsular Florida represents a natural laboratory ideally suited to the study of processes that shape seagrass-associated invertebrate and fish communities within meadows of a single species of seagrass, Thalassia testudinum. This suitability arises from a pronounced structural and chemical gradient that exists over ecologically relevant spatial and temporal scales, as revealed by extensive monitoring of water quality and seagrass. We hypothesized that seagrass-associated invertebrate communities would vary across five estuarine systems spread along a spatial gradient in phosphorus concentration, an important driver of seagrass and phytoplankton growth in this region. The quantitative results based on data acquired at 25 stations (75 samples, 52,086 specimens, and 161 taxa) indicated that each of the five estuarine systems were distinct with regard to species composition and differences among systems were driven by abundant or relatively common species. In addition, we found evidence to indicate food webs in seagrass meadows along this gradient may differ, especially in the relative dominance of algal grazers and predatory invertebrates. These changes in species composition and trophic roles could be driven by phosphorus directly, through increases in rates of primary production with higher concentrations of phosphorus, or indirectly, through nutrient-mediated changes in the physical structure of the seagrass canopy. Our results suggest that differences in the habitat created by T. testudinum under differing phosphorus supplies lead to ecologically significant shifts in macroinvertebrate communities.

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