Dominance determines fish community biomass in a temperate seagrass ecosystem

2019 ◽  
Author(s):  
Aaron Matthius Eger ◽  
Rebecca J. Best ◽  
Julia Kathleen Baum
Keyword(s):  
Species Richness ◽  
Ecosystem Function ◽  
Fish Community ◽  
Prey Capture ◽  
Fish Communities ◽  
Functional Trait ◽  
Ecosystem Functions ◽  
Community Biomass ◽  
Ecosystem Valuation ◽  
Species Abundances

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combined surveys of natural fish communities (conducted in July and August, 2016) with morphological trait data to examine relationships between diversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54° N 130° W). We employed both taxonomic and functional trait measures of diversity to investigate if ecosystem function is driven by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we found that fish community biomass is maximized when taxonomic richness and functional evenness is low, and in communities dominated by species with particular trait values – those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.

scholarly journals Species richness and identity both determine the biomass of global reef fish communities

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jonathan S. Lefcheck ◽  
Graham J. Edgar ◽  
Rick D. Stuart-Smith ◽  
Amanda E. Bates ◽  
Conor Waldock ◽  
...  
Keyword(s):  
Species Richness ◽  
Environmental Factors ◽  
Reef Fish ◽  
Ecosystem Functioning ◽  
Fish Community ◽  
Ecosystem Functions ◽  
Rocky Reef ◽  
Community Biomass ◽  
Number Of Species ◽  
Declining Species

AbstractChanging biodiversity alters ecosystem functioning in nature, but the degree to which this relationship depends on the taxonomic identities rather than the number of species remains untested at broad scales. Here, we partition the effects of declining species richness and changing community composition on fish community biomass across >3000 coral and rocky reef sites globally. We find that high biodiversity is 5.7x more important in maximizing biomass than the remaining influence of other ecological and environmental factors. Differences in fish community biomass across space are equally driven by both reductions in the total number of species and the disproportionate loss of larger-than-average species, which is exacerbated at sites impacted by humans. Our results confirm that sustaining biomass and associated ecosystem functions requires protecting diversity, most importantly of multiple large-bodied species in areas subject to strong human influences.

scholarly journals Influence of Coral Architecture on Species Richness and the Hierarchical Structuration of Species Abundances in Reef Fish Communities: A Case Study in the Eastern Tropical Pacific

2019 ◽  
pp. 1-21
Author(s):  
Jean Béguinot
Keyword(s):  
Species Richness ◽  
Fish Community ◽  
Fish Communities ◽  
Total Species Richness ◽  
Species Abundances ◽  
Hierarchical Structuring ◽  
Complex Architecture ◽  
Total Species

The role of coral reef architecture on species richness and the internal structuration of the associated fish communities has already been addressed several times. The reported results, however, usually remain controversial, possibly because they are based upon incomplete field data issued from partial inventories. Indeed, incomplete samplings are almost unavoidable in practice with such species-rich communities having very uneven distribution of abundances. In this context, the numerical extrapolation of incompletely sampled communities may serve as a reliable surrogate. Accordingly, numerical extrapolations were implemented, here, to compare two fish-communities respectively associated to coral reefs that sharply differ from each-other by their topographic architectures. Both a higher total species richness and a sharper unevenness of species abundances were found to characterize the fish community associated to the more tormented reef habitat exhibiting the more complex architecture. Yet, paradoxically, the true intensity of the underlying process of hierarchical structuring of abundances proves being insensitive to the architecture of coral habitats. This apparent opposition between the unevenness pattern and the underlying structuring process results, in fact, from the additional negative dependence of abundance unevenness upon species richness.

scholarly journals Species richness and food‐web structure jointly drive community biomass and its temporal stability in fish communities

2021 ◽  
Vol 24 (11) ◽  
pp. 2364-2377
Author(s):  
Alain Danet ◽  
Maud Mouchet ◽  
Willem Bonnaffé ◽  
Elisa Thébault ◽  
Colin Fontaine
Keyword(s):  
Species Richness ◽  
Food Web ◽  
Temporal Stability ◽  
Fish Communities ◽  
Food Web Structure ◽  
Community Biomass ◽  
Web Structure

scholarly journals Analyzing the Role of Increasing Water Pollution on Species-Richness, Interspecific-Competition and Abundance-Unevenness in Reef-Associated Fish Communities, off Jakarta Bay (Indonesia)

2021 ◽  
pp. 18-43
Author(s):  
Jean Béguinot
Keyword(s):  
Species Richness ◽  
Interspecific Competition ◽  
Fish Assemblages ◽  
Fish Communities ◽  
Empirical Support ◽  
Feeding Guilds ◽  
Common Trend ◽  
Total Species Richness ◽  
Species Abundances ◽  
The One

Not far from the exceptionally rich ‘Coral Triangle’ on the one hand but, on the other hand, exposed to strongly varying degree of anthropogenic environmental stresses, the reef-associated fish assemblages all along ‘Seribu Islands’ (off Jakarta Bay) are, thus, confronted to both positive and negative ecological influences. As such, these fish assemblages offer especially interesting opportunities to analyze these opposite ecological influences, at both the descriptive and the functional points of views. The least-biased numerical extrapolation of a series of recently reported – yet incomplete – samplings has allowed a sub-exhaustive account of both the estimated total species-richness and the completed distribution of species abundances – including the set of those rarer species which had remained unrecorded. Thanks to this numerically completed information, it became possible to tackle some important issues – which otherwise would have remained difficult to address properly. First, a remarkably good correlation was highlighted between the distance of fish assemblages to Jakarta Bay (distance considered as a reliable surrogate to the improvement of environmental conditions for fish assemblages) and a theoretically derived index characterizing the accommodation capacity of sites for fish assemblages. This good correlation suggests that this index offer a way to reliably accounts for the “environmental quality” of marine waters, as appreciated by fish communities. In quite another respect, comparing primary and secondary-feeding guilds, provides still further empirical support to a seemingly common trend according to which the guild of secondary-feeders features usually more species-rich, while exhibiting less interspecific competition intensity at niche overlaps, than does the primary-feeders guild.

Influence of Tributary Spatial Position on the Structure of Warmwater Fish Communities

1992 ◽  
Vol 49 (4) ◽  
pp. 671-681 ◽  
Author(s):  
Lewis L. Osborne ◽  
Michael J. Wiley
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Fish Species ◽  
Fish Community ◽  
Fish Communities ◽  
Drainage Area ◽  
Physical Habitat ◽  
Drainage Network ◽  
Fish Community Structure ◽  
Stream Size

We found a significant and positive relationship between fish species richness and four measures of stream size (drainage area, stream order, link magnitude, and downstream link) in three Illinois drainage basins. Downstream link (incorporating both stream size and size of stream at the next downstream confluence) explained the greatest portion of the variance. This suggests that downstream processes significantly influence the structure of fish communities inhabiting warmwater streams. Significantly higher numbers of fish species were collected from tributary streams (< 259 km2 drainage area) located lower in a drainage network and connected to a main channel system than from similarly sized streams located in the headwaters of a drainage network. The difference in species richness among station treatments was not due to a difference in the number of individuals collected among treatments. We were unable to accept or reject the hypothesis that differences in fish species richness were due to differences in physical habitat. The immigration–extinction hypothesis appears to provide a plausible explanation for the observed pattern in fish community structure within a drainage. The location of a stream channel within a network may provide a general template for fish community structure in warmwater drainages by regulating potential species richness.

scholarly journals Biogeographical disparity in the functional diversity and redundancy of corals

2018 ◽  
Vol 115 (12) ◽  
pp. 3084-3089 ◽  
Author(s):  
Mike McWilliam ◽  
Mia O. Hoogenboom ◽  
Andrew H. Baird ◽  
Chao-Yang Kuo ◽  
Joshua S. Madin ◽  
...  
Keyword(s):  
Species Richness ◽  
Coral Species ◽  
Multiple Scales ◽  
Functional Trait ◽  
Ecosystem Functions ◽  
Longitudinal Gradients ◽  
Functional Consequences ◽  
Zooxanthellate Coral ◽  
The Persian Gulf ◽  
Trait Space

Corals are major contributors to a range of key ecosystem functions on tropical reefs, including calcification, photosynthesis, nutrient cycling, and the provision of habitat structure. The abundance of corals is declining at multiple scales, and the species composition of assemblages is responding to escalating human pressures, including anthropogenic global warming. An urgent challenge is to understand the functional consequences of these shifts in abundance and composition in different biogeographical contexts. While global patterns of coral species richness are well known, the biogeography of coral functions in provinces and domains with high and low redundancy is poorly understood. Here, we quantify the functional traits of all currently recognized zooxanthellate coral species (n = 821) in both the Indo-Pacific and Atlantic domains to examine the relationships between species richness and the diversity and redundancy of functional trait space. We find that trait diversity is remarkably conserved (>75% of the global total) along latitudinal and longitudinal gradients in species richness, falling away only in species-poor provinces (n < 200), such as the Persian Gulf (52% of the global total), Hawaii (37%), the Caribbean (26%), and the East-Pacific (20%), where redundancy is also diminished. In the more species-poor provinces, large and ecologically important areas of trait space are empty, or occupied by just a few, highly distinctive species. These striking biogeographical differences in redundancy could affect the resilience of critical reef functions and highlight the vulnerability of relatively depauperate, peripheral locations, which are often a low priority for targeted conservation efforts.

scholarly journals Assessing effects of change in land use on size-related variables of fish in subtropical streams

2016 ◽  
Vol 73 (4) ◽  
pp. 547-556 ◽  
Author(s):  
Lluís Benejam ◽  
Franco Teixeira-de Mello ◽  
Mariana Meerhoff ◽  
Marcelo Loureiro ◽  
Erik Jeppesen ◽  
...  
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Species Diversity ◽  
Agricultural Land ◽  
Fish Assemblages ◽  
Fish Communities ◽  
Freshwater Ecosystems ◽  
Ecosystem Functions ◽  
Global Changes ◽  
Fish Length

Transformation of the natural land cover is one of the most important global changes. Changes in land use may strongly affect ecosystem functions and biodiversity by directly or indirectly modifying key structural properties. Here, we examined the effects of land use on the size structure of fish communities in subtropical Uruguayan streams. We analysed the suitability of non-taxonomic, size-related variables as a tool to elucidate shifts in stream fish assemblages along a gradient in land use change. We also tested some taxonomic variables (e.g., species richness and species diversity) to compare their response with size-related variables. In the more anthropogenic disturbed basins (i.e., dominance of urban and agricultural land use), we found higher size diversity, slope of size spectrum (flatter slopes) and total range of fish length, whereas higher species richness, fish abundance and species diversity were detected in more pristine stream basins (i.e., dominance of rangelands). In combination with traditional taxonomic variables, size-related variables of fish communities in streams may be effective tools in evaluating the changes occurring in freshwater ecosystems associated with anthropogenic changes in land use.

scholarly journals Influence of Coral-reef Complexity on Species Richness and the Hierarchical Structuration of Species Abundances in Reef fish Communities: A Case Study in South-east Brazil

2019 ◽  
pp. 1-20
Author(s):  
Jean Béguinot
Keyword(s):  
Species Richness ◽  
Coral Reef ◽  
Reef Fish ◽  
Habitat Complexity ◽  
Fish Communities ◽  
Competitive Intensity ◽  
Total Species Richness ◽  
Species Abundances ◽  
The Mean ◽  
Total Species

Growing complexity of coral habitat is expected to increase resource partitioning among co-occurring reef fish and, thereby, reduce to some extent the mean competitive intensity. This will have associated consequences on the internal structuring of species in reef fish communities, in particular regarding species richness and evenness of species abundances. Accumulating dedicated case studies are necessary, however, to get further empirical confirmations. The present analysis aims to contribute in this respect, comparing reef fish communities associated to two coral-reef settings that markedly differ in their degree of morphological complexity, at Itaipu Sound, Brazil. As the available samplings of these communities remained incomplete, numerical extrapolations were implemented, thereby providing least-bias estimates for both total species richness and the exhaustive distribution of species abundances in both compared reef fish communities. As expected, total species richness increases with greater degree of coral habitat complexity, while the unevenness of species abundances decreases. This decrease in abundance unevenness – reflecting the corresponding relaxation of the mean level of competitive intensity – is partly due to the direct, negative influence of species richness on abundance unevenness, as an overall trend.  Beyond that, however, the relaxation is further strengthened by an additional “genuine” contribution – this time independent from the variation in species richness – and, as such, directly and idiosyncratically attached to the improvement in habitat complexity.

scholarly journals The Who or the How? Species vs. Ecosystem Function Priorities in Conservation Ecology

2021 ◽  
Vol 12 ◽  
Author(s):  
Sebastian Leuzinger ◽  
Boris Rewald
Keyword(s):  
Exotic Species ◽  
Ecosystem Function ◽  
Native Species ◽  
Global Environmental Change ◽  
Target Function ◽  
Functional Trait ◽  
Ecosystem Functions ◽  
Conservation Strategies ◽  
Current Conservation ◽  
Microbial Life

Current conservation strategies are targeted at preserving species, without explicitly aiming at the maintenance of ecosystem functions. In a physically highly connected world, the unintentional relocation of terrestrial, marine, and microbial life is therefore unavoidable and has been an integral part of human evolution for thousands of years. Here, we challenge the default perception often shared among conservation ecologists that preserving native species at all costs and reducing the number of exotic species and their abundance is the only way to conservation and restoration success. While this strategy is valuable in cases where exotic species disrupt ecological function, there are examples where exotic species have similar functional traits to the threatened or extinct native species and can in fact help maintain the overall or target function of an ecosystem. In the race to cope with global environmental change, we argue that ecosystem function and ecosystem services need to be viewed not only through a taxonomic lens, but increasingly also through a functional, trait-based one.

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