Community isolation drives lower fish biomass and species richness, but higher functional evenness, in a river metacommunity

2020 ◽  
Vol 65 (12) ◽  
pp. 2081-2095
Author(s):  
Ana I. Borthagaray ◽  
Franco Teixeira‐de Mello ◽  
Giancarlo Tesitore ◽  
Esteban Ortiz ◽  
Mariana Illarze ◽  
...  
Keyword(s):  
Species Richness ◽  
Fish Biomass ◽  
Functional Evenness

Functional evenness of bird communities varies along the elevational gradient in Europe: Conservation implications

2019 ◽  
Author(s):  
Federico Morelli ◽  
Yanina
Keyword(s):  
Species Richness ◽  
Elevation Gradient ◽  
Bird Species ◽  
Elevational Gradient ◽  
Negative Association ◽  
Bird Communities ◽  
Breeding Bird ◽  
Bird Species Richness ◽  
Large Spatial Scale ◽  
Functional Evenness

ContextThe negative association between elevation and species richness is a well-recognized pattern in macro-ecology. ObjectivesThe aim of this study was to investigate changes in functional evenness of breeding bird communities along an elevation gradient in Europe. MethodsUsing the bird data from the EBCC Atlas of European Breeding Birds we estimated an index of functional evenness which can be assumed as a measure of the potential resilience of communities.ResultsOur findings confirm the existence of a negative association between elevation and bird species richness in all European eco regions. However, we also explored a novel aspect of this relationship, important for conservation: Our findings provide evidence at large spatial scale of a negative association between the functional evenness (potential community resilience) and elevation, independent of the eco region. We also found that the Natura2000 protected areas covers the territory most in need of protection, those characterized by bird communities with low potential resilience, in hilly and mountainous areas.ConclusionsThese results draw attention to European areas occupied by bird communities characterized by a potential lower capacity to respond to strong ecological changes, and, therefore, potentially more exposed to risks for conservation.

Littoral Fish Communities in Southern Quebec Lakes: Relationships with Limnological and Prey Resource Variables

1994 ◽  
Vol 51 (5) ◽  
pp. 1128-1138 ◽  
Author(s):  
Clay L. Pierce ◽  
Joseph B. Rasmussen ◽  
William C. Leggett
Keyword(s):  
Species Richness ◽  
Fish Species ◽  
Yellow Perch ◽  
Fish Communities ◽  
Principal Component ◽  
Lepomis Gibbosus ◽  
Fish Biomass ◽  
Littoral Fish ◽  
Total Fish ◽  
Invertebrate Biomass

We assessed species richness, biomass, and community type of littoral fish in 10 southern Quebec lakes in relation to several limnological and prey resource variables. Lake, yearly, and seasonal variation in biomass was evaluated by quantitative, replicated seining. Species richness averaged 12.8 in our lakes, and 24 species were collected overall. Total littoral fish biomass averaged 13.5 g∙m−2 overall and varied significantly among lakes (range 6.1–26.9 g∙m−2) and between early and late summer. Yellow perch (Perca flavescens), golden shiner (Notemigonus crysoleucas), and pumpkinseed (Lepomis gibbosus) occurred in all lakes and were the most abundant species overall, averaging 57% of the total fish biomass. Principal component ordination of littoral fish communities showed little evidence for aggregation of community types. Species richness was positively correlated with lake surface area (r2 = 0.62), as has been shown in other studies. Total fish biomass was positively correlated with biomass of chironomids (r2 = 0.57), which constituted 24% of the littoral invertebrate biomass in our lakes and are important prey of many fish species. We found no significant correlation between total fish biomass and total invertebrate biomass or between biomass of any of the dominant fish species and limnological or prey variables.

scholarly journals Biodiversity–ecosystem functioning relationships in fish communities: biomass is related to evenness and the environment, not to species richness

2019 ◽  
Vol 286 (1906) ◽  
pp. 20191189 ◽  
Author(s):  
Aurore Maureaud ◽  
Dorothee Hodapp ◽  
P. Daniël van Denderen ◽  
Helmut Hillebrand ◽  
Henrik Gislason ◽  
...  
Keyword(s):  
Species Richness ◽  
Ecosystem Functioning ◽  
Structural Equation ◽  
Fish Assemblages ◽  
Current Knowledge ◽  
Marine Ecosystem ◽  
Experimental Studies ◽  
Fish Communities ◽  
Trophic Levels ◽  
Fish Biomass

The relationship between biodiversity and ecosystem functioning (BEF) is a topic of considerable interest to scientists and managers because a better understanding of its underlying mechanisms may help us mitigate the consequences of biodiversity loss on ecosystems. Our current knowledge of BEF relies heavily on theoretical and experimental studies, typically conducted on a narrow range of spatio-temporal scales, environmental conditions, and trophic levels. Hence, whether a relationship holds in the natural environment is poorly understood, especially in exploited marine ecosystems. Using large-scale observations of marine fish communities, we applied a structural equation modelling framework to investigate the existence and significance of BEF relationships across northwestern European seas. We find that ecosystem functioning, here represented by spatial patterns in total fish biomass, is unrelated to species richness—the most commonly used diversity metric in BEF studies. Instead, community evenness, differences in species composition, and abiotic variables are significant drivers. In particular, we find that high fish biomass is associated with fish assemblages dominated by a few generalist species of a high trophic level, who are able to exploit both the benthic and pelagic energy pathway. Our study provides a better understanding of the mechanisms behind marine ecosystem functioning and allows for the integration of biodiversity into management considerations.

scholarly journals Common latitudinal gradients in functional richness and functional evenness across marine and terrestrial systems

2019 ◽  
Vol 286 (1908) ◽  
pp. 20190745 ◽  
Author(s):  
M. Schumm ◽  
S. M. Edie ◽  
K. S. Collins ◽  
V. Gómez-Bahamón ◽  
K. Supriya ◽  
...  
Keyword(s):  
Species Richness ◽  
Functional Groups ◽  
Functional Diversity ◽  
Skewed Distribution ◽  
Model Systems ◽  
Latitudinal Gradients ◽  
Ecological Specialization ◽  
Functional Richness ◽  
The Tropics ◽  
Functional Evenness

Functional diversity is an important aspect of biodiversity, but its relationship to species diversity in time and space is poorly understood. Here we compare spatial patterns of functional and taxonomic diversity across marine and terrestrial systems to identify commonalities in their respective ecological and evolutionary drivers. We placed species-level ecological traits into comparable multi-dimensional frameworks for two model systems, marine bivalves and terrestrial birds, and used global species-occurrence data to examine the distribution of functional diversity with latitude and longitude. In both systems, tropical faunas show high total functional richness (FR) but low functional evenness (FE) (i.e. the tropics contain a highly skewed distribution of species among functional groups). Functional groups that persist toward the poles become more uniform in species richness, such that FR declines and FE rises with latitude in both systems. Temperate assemblages are more functionally even than tropical assemblages subsampled to temperate levels of species richness, suggesting that high species richness in the tropics reflects a high degree of ecological specialization within a few functional groups and/or factors that favour high recent speciation or reduced extinction rates in those groups.

scholarly journals The importance of sponges and mangroves in supporting fish communities on degraded coral reefs in Caribbean Panama

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4455 ◽  
Author(s):  
Janina Seemann ◽  
Alexandra Yingst ◽  
Rick D. Stuart-Smith ◽  
Graham J. Edgar ◽  
Andrew H. Altieri
Keyword(s):  
Species Richness ◽  
Coral Reefs ◽  
Trophic Structure ◽  
Small Body ◽  
Fish Communities ◽  
Trophic Levels ◽  
Fish Biomass ◽  
Seagrass Meadows ◽  
Total Fish ◽  
The Caribbean

Fish communities associated with coral reefs worldwide are threatened by habitat degradation and overexploitation. We assessed coral reefs, mangrove fringes, and seagrass meadows on the Caribbean coast of Panama to explore the influences of their proximity to one another, habitat cover, and environmental characteristics in sustaining biomass, species richness and trophic structure of fish communities in a degraded tropical ecosystem. We found 94% of all fish across all habitat types were of small body size (≤10 cm), with communities dominated by fishes that usually live in habitats of low complexity, such as Pomacentridae (damselfishes) and Gobiidae (gobies). Total fish biomass was very low, with the trend of small fishes from low trophic levels over-represented, and top predators under-represented, relative to coral reefs elsewhere in the Caribbean. For example, herbivorous fishes comprised 27% of total fish biomass in Panama relative to 10% in the wider Caribbean, and the small parrotfishScarus isericomprised 72% of the parrotfish biomass. We found evidence that non-coral biogenic habitats support reef-associated fish communities. In particular, the abundance of sponges on a given reef and proximity of mangroves were found to be important positive correlates of reef fish species richness, biomass, abundance and trophic structure. Our study indicates that a diverse fish community can persist on degraded coral reefs, and that the availability and arrangement within the seascape of other habitat-forming organisms, including sponges and mangroves, is critical to the maintenance of functional processes in such ecosystems.

Fish of channelized and unchannelized sections of the Bunyip River, Victoria

1983 ◽  
Vol 34 (3) ◽  
pp. 441 ◽  
Author(s):  
KG Hortle ◽  
PS Lake
Keyword(s):  
Species Richness ◽  
Native Fish ◽  
Suitable Habitat ◽  
Numerical Density ◽  
Fish Biomass ◽  
Introduced Fish ◽  
Slack Water ◽  
Total Fish ◽  
The Common ◽  
Australian Grayling

The distribution and abundance of fish at three channelized and three unchannelized sites on the Bunyip River in southern Victoria were investigated. Ten species of native fish, including the Australian grayling (Prototroctes maraena), and two species of introduced fish were collected in three sets of seasonal samples by electrofishing. The unchannelized sites and a channelized site directly above a small weir had significantly higher species richness, total fish biomass, numerical density and standing crop (P<0.05) than the other two channelized sites. Ammocoete lamprey larvae, short-finned eels, southern pigmy perch and brown trout were most abundant at the unchannelized sites, whereas the common jollytail was most abundant at the channelized sites. Total numbers and biomass of fish and species richness were all positively correlated (P<0.01) with the area of snags present, and species richness and fish biomass correlated positively (P<0.01) with the area of slack water. It appears that the absence of suitable habitat (viz, area of snags, area of slack water, length of bank fringed with vegetation) accounts for the lower abundance and lower species richness of fish after channelization. A small weir at one of the channelized sites ameliorated partly the effects of channelization.

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.

Plant diversity and species richness of Ljubljana marsh grasslands under the influence of different cutting and fertilizing regimes

2009 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
T. Sinkovč
Keyword(s):  
Species Richness ◽  
Plant Diversity ◽  
Grassland Management ◽  
Botanical Composition ◽  
Significant Negative Effect ◽  
Negative Effect ◽  
Cutting Regimes ◽  
N Rates ◽  
Exploitation Intensity ◽  
Plot Design

The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).

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