Community Ecology of Stream Fishes: Concepts, Approaches, and Techniques

2010 ◽  
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Community Ecology ◽  
Community Dynamics ◽  
Spatial Scales ◽  
River Mouth ◽  
Extrinsic Factors ◽  
Local Species Richness ◽  
Community Convergence ◽  
Local Filters

<em>Abstract</em>.—Community ecology increasingly seeks to integrate the influences of regional and historical processes with species interactions within local habitats. This broadened perspective is largely based on comparative approaches that employ “natural experiments” to identify factors shaping community structure. Because coastal rivers are separated from one another by insurmountable barriers (oceans or land), freshwater fishes are particularly well suited for comparative analyses of factors that influence fish community organization. In this chapter, we review how this comparative approach shed light on large-scale biodiversity gradients, community saturation, community convergence, density compensation, and the role of intrinsic and extrinsic factors in community dynamics. The main factors (e.g., river mouth discharge and history) empirically related to species richness of a river are well identified, and metacommunity ecology provides a fruitful conceptual framework for understanding how regional (river) species richness translates into local species richness. Much work remains to identify factors explaining differences among whole river basin assemblages with regard to ecological traits (e.g., trophic status and life history) composition and to assess whether trait-related environmental and biotic local filters act similarly over large spatial scales. One important conclusion that can be drawn from the studies reviewed here is that history cannot be neglected whatever the scale of investigation (global, river, or site). A second conclusion is that historical effects are not strong enough to blur the occurrence of qualitatively repeatable patterns of community structure over large spatial scale, which is encouraging because it suggests development of general predictive models of community structure is an attainable goal.

scholarly journals Responses of community structure and diversity to nitrogen deposition and rainfall addition in contrasting steppes are ecosystem-dependent and dwarfed by year-to-year community dynamics

2019 ◽  
Vol 124 (3) ◽  
pp. 461-469 ◽  
Author(s):  
Xuejun Yang ◽  
Zhenying Huang ◽  
Ming Dong ◽  
Xuehua Ye ◽  
Guofang Liu ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Global Change ◽  
Nitrogen Deposition ◽  
Community Composition ◽  
Community Dynamics ◽  
Environmental Variability ◽  
The Other ◽  
Desert Steppe ◽  
Typical Steppe

Abstract Background and Aims Long-term studies to disentangle the multiple, simultaneous effects of global change on community dynamics are a high research priority to forecast future distribution of diversity. Seldom are such multiple effects of global change studied across different ecosystems. Methods Here we manipulated nitrogen deposition and rainfall at levels realistic for future environmental scenarios in three contrasting steppe types in Mongolia and followed community dynamics for 7 years. Key Results Redundancy analyses showed that community composition varied significantly among years. Rainfall and nitrogen manipulations did have some significant effects, but these effects were dependent on the type of response and varied between ecosystems. Community compositions of desert and meadow steppes, but not that of typical steppe, responded significantly to rainfall addition. Only community composition of meadow steppe responded significantly to nitrogen deposition. Species richness in desert steppe responded significantly to rainfall addition, but the other two steppes did not. Typical steppe showed significant negative response of species richness to nitrogen deposition, but the other two steppes did not. There were significant interactions between year and nitrogen deposition in desert steppe and between year and rainfall addition in typical steppe, suggesting that the effect of the treatments depends on the particular year considered. Conclusions Our multi-year experiment thus suggests that responses of community structure and diversity to global change drivers are ecosystem-dependent and that their responses to experimental treatments are dwarfed by the year-to-year community dynamics. Therefore, our results point to the importance of taking annual environmental variability into account for understanding and predicting the specific responses of different ecosystems to multiple global change drivers.

scholarly journals The Best of All Worlds: Streptococcus pneumoniae Conjunctivitis through the Lens of Community Ecology and Microbial Biogeography

2019 ◽  
Vol 8 (1) ◽  
pp. 46 ◽  
Author(s):  
Lawson Ung ◽  
Paulo J. M. Bispo ◽  
Noelle C. Bryan ◽  
Camille Andre ◽  
James Chodosh ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Community Ecology ◽  
Disease Transmission ◽  
Community Dynamics ◽  
Spatial Scales ◽  
Microbial World ◽  
Next Generation Sequencing Technology ◽  
Microbial Biogeography ◽  
Ecological Principles ◽  
Population Structures

The study of the forces which govern the geographical distributions of life is known as biogeography, a subject which has fascinated zoologists, botanists and ecologists for centuries. Advances in our understanding of community ecology and biogeography—supported by rapid improvements in next generation sequencing technology—have now made it possible to identify and explain where and why life exists as it does, including within the microbial world. In this review, we highlight how a unified model of microbial biogeography, one which incorporates the classic ecological principles of selection, diversification, dispersion and ecological drift, can be used to explain community dynamics in the settings of both health and disease. These concepts operate on a multiplicity of temporal and spatial scales, and together form a powerful lens through which to study microbial population structures even at the finest anatomical resolutions. When applied specifically to curious strains of conjunctivitis-causing, nonencapsulated Streptococcus pneumoniae, we show how this conceptual framework can be used to explain the possible evolutionary and disease-causing mechanisms which allowed these lineages to colonize and invade a separate biogeography. An intimate knowledge of this radical bifurcation in phylogeny, still the only known niche subspecialization for S. pneumoniae to date, is critical to understanding the pathogenesis of ocular surface infections, nature of host-pathogen interactions, and developing strategies to curb disease transmission.

scholarly journals Variation of plant species richness at different spatial scales

2018 ◽  
Vol 11 ◽  
pp. 49-62 ◽  
Author(s):  
Khem Raj Bhattarai
Keyword(s):  
Species Richness ◽  
Spatial Scales ◽  
Local Scale ◽  
Explanatory Variables ◽  
Local Species Richness ◽  
Β Diversity ◽  
Historical Processes ◽  
Α Diversity ◽  
Local Species ◽  
Broad Scale

 It is now realized that the variation in species richness is influenced by spatial and temporal scales. Pattern and scale are a central focus in ecology and biogeography. The species richness relationship depends on the scale of study and their correlated factors. The broad objective of this review is to elucidate how different scales are correlated with different explanatory variables to generate patterns of species richness. Addressing the problem of scale has both fundamental and applied importance in understanding variation in species richness along gradients. The understanding of pattern, its causes, and consequences is central to our understanding of processes such as succession, community development, and the spread and persistence of species. According to the hierarchical theory of species diversity there are mainly three categories of scales: local, landscape and regional. The local species richness or α-diversity is the diversity of individual stands. The β-diversity or species change is turnover between two elevational bands or between two plots or two sites. The regional or γ-diversity is the total richness of whole mountains or study systems and it has a combined influence from α- and β-diversity. The local species richness is affected by both local-scale processes (e.g., internal interactions) and broad-scale processes (e.g., evolutionary). Different explanatory variables according to the scales of study are necessary to explain variation at different spatial scales. Local factors (e.g., disturbance, grazing and tree cover) have been used to detect variation at a local scale. Generally, topographical factors are used to detect variation in species richness at a landscape scale; whereas climate, water-energy dynamics and historical processes are used to detect variation at a regional scale. However, it is not easy to separate strictly one scale from other because there is no clear boundary between them. The study of the whole elevation gradient from tropical to alpine zone or long latitude is a broad-scale study. The intermediate scale is a study on a local mountain, which covers the subtropical to warm temperate zones. To explain patterns of species richness, a pluralistic body of hypotheses, which incorporates historical, biological and climatic factors, is needed. This is depicted by the strong relationship between climate, biological interactions, and historical processes in influencing variation in species richness at different spatial scales.Botanica Orientalis – Journal of Plant Science (2017) 11: 49–62

Variation in the components of Benthic community structure in a Coastal Lagoon as a function of Spatial Scale

1989 ◽  
Vol 40 (1) ◽  
pp. 79 ◽  
Author(s):  
A Hatcher
Keyword(s):  
Community Structure ◽  
Community Composition ◽  
Coastal Lagoon ◽  
Benthic Community ◽  
Spatial Scales ◽  
Small Scale ◽  
Benthic Community Structure ◽  
Extrinsic Factors ◽  
Sessile Invertebrates ◽  
Community Types

The perception of community structure is strongly related to the spatial resolution of data collection. To quantify variation in community structure at several spatial scales, the benthos was examined on the limestone substratum in a nearshore coastal lagoon. Community structure was described using a form of pattern analysis called correspondence analysis. Variance at three spatial scales was measured. These scales were described as: (I) between offshore and nearshore reefs (kilometres); (2) among areas on the nearshore reef-line (< 1 km); and (3) between community types on the nearshore reef-line (tens of metres and less). Organisms were classified according to higher taxa/functional classes. Parameters which varied between reef-lines included: (i) community composition determined using multivariate ordination, (ii) cover by calcareous and filamentous algae and (iii) abundance of seagrass and juvenile kelp (Ecklonia radiata). Among the areas on the nearshore reef-line, variance in community composition was due to the distribution of animals. There was a south to north gradient of increasing cover by encrusting animals and abundance of ascidians. Within the areas on the nearshore reef-line, there were two distinct community types characterized by macrophytic plants or sessile invertebrates. The major potential controls of the variation in benthic community structure were different at each of the spatial scales examined. The strong relationships between extrinsic factors and components of the communities suggested that the major potential controls were: (a) exposure to swell at the large scale (between reef-lines), (b) availability of food at the medium scale (within areas on the nearshore reef-line) and (c) biological interactions or responses to microtopography and light climate at the small scale (between and within communities on the nearshore reef-line).

scholarly journals Fine-Scale Mapping of Mega-Epibenthic Communities and Their Patch Characteristics on Two New Zealand Seamounts

2021 ◽  
Vol 8 ◽  
Author(s):  
Savannah L. Goode ◽  
Ashley A. Rowden ◽  
David A. Bowden ◽  
Malcolm R. Clark ◽  
Fabrice Stephenson
Keyword(s):  
Community Structure ◽  
New Zealand ◽  
Environmental Variables ◽  
Community Dynamics ◽  
Spatial Scales ◽  
Benthic Communities ◽  
Environmental Drivers ◽  
Fine Scale ◽  
Patch Characteristics ◽  
Epibenthic Communities

Seamounts are common features of the deep seafloor that are often associated with aggregations of mega-epibenthic fauna, including deep-sea corals and sponges. Globally, many seamounts also host abundant fish stocks, supporting commercial bottom trawl fisheries that impact non-target benthic species through damage and/or removal of these non-target species. However, the effects of bottom trawling on seamount benthic communities, as well as their recovery potential, will vary over the total seamount area because of differences in within seamount habitat and community structure. It is therefore important to understand fine-scale community dynamics, community patch characteristics, and the environmental drivers contributing to these patterns to improve habitat mapping efforts on seamounts and to determine the potential for benthic communities on seamounts to recover from fishing disturbances. Here we analysed the structure and distribution of mega-epibenthic communities on two New Zealand seamounts with different physical environments to determine which environmental variables best correlated with variation in community structure within each seamount. We used the identified environmental variables to predict the distribution of communities beyond the sampled areas, then described the spatial patterns and patch characteristics of the predicted community distributions. We found the environmental variables that best explained variations in community structure differed between the seamounts and at different spatial scales. These differences were reflected in the distribution models: communities on one seamount were predicted to form bands with depth, while on the other seamount communities varied mostly with broadscale aspect and the presence of small pinnacles. The number and size of community patches, inter-patch distances, and patch connectedness were found to differ both within and between seamounts. These types of analyses and results can be used to inform the spatial management of seamount ecosystems.

scholarly journals Saproxylic species are linked to the amount and isolation of dead wood across spatial scales in a beech forest

2020 ◽  
Author(s):  
Elena Haeler ◽  
Ariel Bergamini ◽  
Stefan Blaser ◽  
Christian Ginzler ◽  
Karin Hindenlang ◽  
...  
Keyword(s):  
Species Richness ◽  
Spatial Scale ◽  
Beta Diversity ◽  
Dead Wood ◽  
Spatial Scales ◽  
Beech Forest ◽  
Habitat Amount ◽  
Alpha And Beta Diversity ◽  
Local Species Richness ◽  
Saproxylic Species

Abstract Context Dead wood is a key habitat for saproxylic species, which are often used as indicators of habitat quality in forests. Understanding how the amount and spatial distribution of dead wood in the landscape affects saproxylic communities is therefore important for maintaining high forest biodiversity. Objectives We investigated effects of the amount and isolation of dead wood on the alpha and beta diversity of four saproxylic species groups, with a focus on how the spatial scale influences results. Methods We inventoried saproxylic beetles, wood-inhabiting fungi, and epixylic bryophytes and lichens on 62 plots in the Sihlwald forest reserve in Switzerland. We used GLMs to relate plot-level species richness to dead wood amount and isolation on spatial scales of 20–200 m radius. Further, we used GDMs to determine how dead wood amount and isolation affected beta diversity. Results A larger amount of dead wood increased beetle richness on all spatial scales, while isolation had no effect. For fungi, bryophytes and lichens this was only true on small spatial scales. On larger scales of our study, dead wood amount had no effect, while greater isolation decreased species richness. Further, we found no strong consistent patterns explaining beta diversity. Conclusions Our multi-taxon study shows that habitat amount and isolation can strongly differ in the spatial scale on which they influence local species richness. To generally support the species richness of different saproxylic groups, dead wood must primarily be available in large amounts but should also be evenly distributed because negative effects of isolation already showed at scales under 100 m.

Savanna fires govern community structure of ungulates in Bénoué National Park, Cameroon

2008 ◽  
Vol 24 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Erik Klop ◽  
Janneke van Goethem
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Body Mass ◽  
National Park ◽  
Virtual Communities ◽  
Spatial Scales ◽  
West African ◽  
Species Density ◽  
Savanna Fires ◽  
Occurrence Patterns

Abstract:We studied the effects of savanna fires on the structure of local ungulate communities in a West African woodland savanna. The distribution of 11 ungulate species over 9−15 burned sites (the number of which increased as burning activity continued during the dry season) and 7−13 unburned sites was compared with a variety of null models or randomized ‘virtual communities’. Five different parameters of community structure were examined: body mass distribution, co-occurrence patterns, species richness, species density and guild dominance. Overall, ungulate species were not randomly distributed over burned and unburned sites. The regular spacing of body masses in the set of species recorded on burned and unburned sites indicated competition, since species similar in body mass are more likely to compete than species of different size. However, co-occurrence patterns on burned sites were random, indicating absence of competition at fine spatial scales due to differential habitat use within the burned landscape. Although the attractiveness of the regrowth on burned sites resulted in higher numbers of ungulates compared with unburned sites, species richness was not different. Grazers were the dominant guild on burned sites, but there were no differences in species richness or species density between grazers and browsers on unburned sites.

scholarly journals Nutrients and herbivores impact grassland stability across multiple spatial scales through different pathways

2021 ◽  
Author(s):  
Q. Q. Chen ◽  
Shaopeng Wang ◽  
Eric Seabloom ◽  
Andrew MacDougall ◽  
Elizabeth Borer ◽  
...  
Keyword(s):  
Species Richness ◽  
Local Community ◽  
Spatial Scales ◽  
Temporal Stability ◽  
Local Communities ◽  
Nutrient Addition ◽  
Local Species Richness ◽  
Herbivore Exclusion ◽  
Local Species ◽  
Independent Effects

Nutrients and herbivores have independent effects on the temporal stability of aboveground biomass in grasslands; however, their joint effects may not be additive and may also depend on spatial scales. In an experiment adding nutrients and excluding herbivores in 34 globally distributed grasslands, we found that nutrients and herbivores mainly had additive effects. Nutrient addition consistently reduced stability at the local and larger spatial scales (aggregated local communities), while herbivore exclusion weakly reduced stability at these scales. Moreover, nutrient addition reduced stability primarily by causing changes in local community composition over time and by reducing local species richness and evenness. In contrast, herbivore exclusion weakly reduced stability at the larger scale mainly by decreasing asynchronous dynamics among local communities, but also by weakly decreasing local species richness. Our findings indicate disentangling the influences of processes operating at different spatial scales may improve conservation and management in stabilizing grassland biomass.

scholarly journals Mapping differences in mammalian distributions and diversity using environmental DNA from rivers

2021 ◽  
Author(s):  
Holly A. Broadhurst ◽  
Luke M. Gregory ◽  
Emma K. Bleakley ◽  
Joseph C. Perkins ◽  
Jenna V. Lavin ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Dynamics ◽  
Spatial Scales ◽  
Environmental Dna ◽  
Community Diversity ◽  
Individual Species ◽  
Sampling Effort ◽  
Mammal Species ◽  
Terrestrial Mammals ◽  
Β Diversity

AbstractAimFinding more efficient ways to monitor, and estimate the diversity of, mammalian communities is a major step towards their management and conservation. Environmental DNA (eDNA) from river water has recently been shown to be a viable method for biomonitoring mammalian communities. Yet, most of the studies to date have focused on the potential for eDNA to detect individual species, with little focus on describing patterns of community diversity and structure. In this study, we focus on the sampling effort required to reliably map the diversity and distribution of semi-aquatic and terrestrial mammals and allow inferences of community structure surrounding rivers.LocationSoutheastern EnglandMethodsWe used eDNA metabarcoding on water samples collected along two rivers and a beaver enclosure over two days, targeting terrestrial and semi-aquatic mammals. Mammalian community diversity and composition was assessed based on species richness and β-diversity. Differences between river communities were calculated and partitioned into nestedness and turnover, and the sampling effort required to rapidly detect semi-aquatic and terrestrial species was evaluated based on species accumulation curves and occupancy modelling.ResultseDNA metabarcoding efficiently detected 25 wild mammal species from five orders in two days of sampling, representing the vast majority (82%) of the species expected in the area. The required sampling effort varied between orders, with common species (generally rodents, deer and lagomorph species) more readily detected, with carnivores detected less frequently. Measures of species richness differed between rivers (both overall and within each mammalian order) and patterns of β-diversity revealed the importance of species replacement in sites within each river, against a pattern of species loss between the two rivers.Main conclusionseDNA metabarcoding demonstrated its capability to rapidly detect mammal species, allowing inferences of community composition that will better inform future sampling strategies for this Class. Importantly, this study highlights the potential use of eDNA data for investigating mammalian community dynamics over different spatial scales.

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