scholarly journals Relationships between latitude and environmental conditions and the species richness, abundance and composition of tropical fish assemblages over soft substrata

2012 ◽  
Vol 446 ◽  
pp. 221-241 ◽  
Author(s):  
MJ Travers ◽  
IC Potter ◽  
KR Clarke ◽  
SJ Newman
Keyword(s):  
Species Richness ◽  
Environmental Conditions ◽  
Fish Assemblages ◽  
Tropical Fish

Effects of an anti-salt intrusion dam on tropical fish assemblages

2010 ◽  
Vol 61 (3) ◽  
pp. 288 ◽  
Author(s):  
Tuantong Jutagate ◽  
Amonsak Sawusdee ◽  
Thanitha Thapanand-Chaidee ◽  
Sovan Lek ◽  
Gaël Grenouillet ◽  
...  
Keyword(s):  
Species Richness ◽  
Chlorophyll A ◽  
Environmental Conditions ◽  
Fish Assemblages ◽  
Diversity Index ◽  
Tropical Fish ◽  
Food Sources ◽  
Salt Intrusion ◽  
Open Phase ◽  
Salinity Gradients

Following the construction of an anti-salt intrusion dam in Pak Panang River, Thailand, changes in the environmental conditions and fish assemblages were monitored both in the estuary and in the river. The present study was conducted during two different phases: when the sluices were open; and when they were closed. Salinity in the estuary declined (P < 0.001), but increased in the river during the open phase (P = 0.002). In the river, the pH increased (P < 0.001) during the closed phase, but was relatively constant in the estuary. No differences were found for water temperatures, chlorophyll a and abundance of phytoplankton. During the closed phase, the abundance of zooplankton was higher in the estuary, but the abundance of benthos in the river declined. Ninety-four fish species were collected. Species richness and the diversity index did not differ in the estuary, but were significantly different in the river; abundance was higher during the open phase. Fish moved between the two systems during the open phase and changes in fish assemblages correlated with salinity gradients and food sources. Sluice regulation to allow fish to move between the river and the estuary is recommended.

Distribution, abundance, and diversity of stream fishes under variable environmental conditions

2006 ◽  
Vol 63 (1) ◽  
pp. 43-54 ◽  
Author(s):  
Christopher M Taylor ◽  
Thomas L Holder ◽  
Riccardo A Fiorillo ◽  
Lance R Williams ◽  
R Brent Thomas ◽  
...  
Keyword(s):  
Species Richness ◽  
Environmental Conditions ◽  
Community Dynamics ◽  
Local Community ◽  
Fish Assemblages ◽  
Fish Distribution ◽  
Stream Fish ◽  
Spatial And Temporal Variability ◽  
Regional Patterns ◽  
Abundance And Diversity

The effects of stream size and flow regime on spatial and temporal variability of stream fish distribution, abundance, and diversity patterns were investigated. Assemblage variability and species richness were each significantly associated with a complex environmental gradient contrasting smaller, hydrologically variable stream localities with larger localities characterized by more stable flow regimes. Assemblages showing the least variability were the most species-rich and occurred in relatively large, stable environments. Theory suggests that species richness can be an important determinant of assemblage variability. Although this appears to be true in our system, we suggest that spatial and temporal heterogeneity in the environment largely determines both assemblage richness and variability, providing a more parsimonious explanation for the diversity–variability correlation. Changes in species richness of local assemblages across time were coordinated across the landscape, and assemblages formed spatially and temporally nested subset patterns. These results suggest an important link between local community dynamics and community-wide occurrence. At the species level, mean local persistence was significantly associated with regional occurrence. Thus, the more widespread a species was, the greater its local persistence. Our results illustrate how the integrity of local stream fish assemblages is dependent on local environmental conditions, regional patterns of species distribution, and landscape continuity.

scholarly journals Seagrass Structural Traits Drive Fish Assemblages in Small-Scale Fisheries

2021 ◽  
Vol 8 ◽  
Author(s):  
Benjamin L. Jones ◽  
Lina M. Nordlund ◽  
Richard K. F. Unsworth ◽  
Narriman S. Jiddawi ◽  
Johan S. Eklöf
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Fish Assemblages ◽  
Human Impacts ◽  
Structural Complexity ◽  
Tropical Fish ◽  
Small Scale ◽  
Seagrass Species ◽  
Seagrass Meadows ◽  
Seagrass Cover

Seagrasses – a group of foundation species in coastal ecosystems – provide key habitat for diverse and abundant faunal assemblages and support numerous ecosystem functions and services. However, whether the habitat role of seagrasses is influenced by seagrass diversity, by dominant species or both, remains unclear. To that end, we sought to investigate the specific seagrass characteristics (e.g., species diversity, seagrass traits) that influence tropical fish assemblages, and place this in the context of small-scale fishery use. We surveyed seagrass variables at 55 plots, nested within 12 sites around Zanzibar (Tanzania) in the Western Indian Ocean, and used Baited Remote Underwater Video (BRUV) systems to assess fish assemblages across plots. Using linear mixed models, we reveal that seagrass structural complexity and depth were the best predictors of fish abundance, with higher abundance occurring in deeper meadows or meadows with high canopy, leaf length and number of leaves per shoot. Moreover, an interaction between seagrass cover and land-use was the best predictor of fish species richness, where sites closer to human impacts were less affected by cover than sites with lower human impact. Overall, models with seagrass species richness or functional diversity as predictors poorly explained fish assemblages. Fish taxa that were important for small-scale fishery sectors (e.g., emperors, snappers, rabbitfish, and parrotfish) were primarily driven by seagrass structural complexity. Our results provide a unique analysis of the relationship between seagrass habitat and its associated fish assemblages in that we show that seagrass species diversity had little effect on seagrass fish assemblages, which instead appear driven by specific seagrass traits and seagrass cover. If conserving high value species that support adjacent fisheries is the priority for protecting seagrass meadows, then seagrass areas should be chosen with high cover and structural complexity that are in deeper waters. Any conservation measures also need to balance the needs of fishers that use the resources supported by seagrasses.

Cyprinid distributions in Northeast U.S.A. lakes: evidence of regional-scale minnow biodiversity losses

1997 ◽  
Vol 54 (7) ◽  
pp. 1593-1607 ◽  
Author(s):  
T R Whittier ◽  
D B Halliwell ◽  
S G Paulsen
Keyword(s):  
New York ◽  
Species Richness ◽  
New England ◽  
Fish Assemblages ◽  
Regional Scale ◽  
Median Number ◽  
Southern New England ◽  
Sample Data ◽  
Golden Shiner ◽  
Northern New England

Fish assemblages were sampled in 195 randomly selected lakes in the northeastern United States during the summers of 1991-1994. Most lakes in northern Maine had three to seven minnow species, constituting 40-80% of species in each lake. Lakes in New Jersey, southern New York, and southern New England rarely had minnows, other than golden shiner (Notemigonus crysoleucas). Lakes in the Adirondacks and the remainder of northern New England had intermediate numbers. We examined minnow native ranges and autecology and evaluated species richness related to littoral predators and human disturbance. Sample data suggested alteration in the minnow assemblages over much of the region. The most consistent factor related to minnow species richness was the presence of littoral predators. Median number of minnow species was two in lakes lacking predators and zero in lakes with predators. Non-native predators, especially Micropterus spp., have been introduced throughout the Northeast; 69% of the sampled lakes had non-native predators. In the absence of predators, minnow species declined with increased human activity in the watershed and along lake shorelines. Only in northern Maine did lake minnow assemblages seem relatively intact.

scholarly journals Diversité des insectes floricoles de Abelmoschus esculentus (Malvaceae) et leur impact sur les rendements fruitier et grainier à Maroua-Cameroun.

2020 ◽  
Vol 43:1 ◽  
pp. 7350-7365
Author(s):  
Joseph Blaise Pando ◽  
Denis Djonwangwé ◽  
Olivier Balti Moudelsia ◽  
Fernand-Nestor Tchuenguem Fohouo ◽  
Joseph Lebel Tamesse
Keyword(s):  
Species Richness ◽  
Environmental Conditions ◽  
Relative Frequency ◽  
Positive Impact ◽  
Abelmoschus Esculentus ◽  
Flowering Period ◽  
Flower Buds ◽  
Protection Contre ◽  
Pollinating Insects ◽  
Number Of Seeds

Pour déterminer la richesse spécifique, la fréquence relative, les produits alimentaires recherchés, les insectes pollinisateurs et l’impact de ces insectes sur les rendements, deux traitements ont été formés à partir du marquage de 240 boutons floraux en 2015 et 2017 chacun selon la présence ou l’absence de protection contre les insectes. Les observations ont été faites sur les fleurs de Abelmoschus esculentus en libre pollinisation du 11 au 22 septembre 2015 et du 7 au 19 septembre 2017 à Wourndé et Palar respectivement. La diversité spécifique des insectes floricoles de gombo était de 17 et 20 espèces respectivement à Wourndé et à Palar. L’indice de Jacard (J = 0,15) révèle une similarité entre les deux sites, preuve que les conditions environnementales sont similaires dans les deux habitats. Les insectes butinaient les fleurs du gombo de 8 h à 13 h, avec le pic de l’activité de l’ensemble de visites de ceux-ci situé entre 10 h et 11 h. Les insectes développaient un comportement très élaboré lors de la récolte du nectar et/ou du pollen et la consommation du pétale. On peut regrouper ces insectes en pollinisateur majeur (Lipotriches collaris), pollinisateurs mineurs [Sphecodes albilabris, Camponotus flavomarginatus, le Vespidae (1 sp.), Lasioglossum albilabris, Seladonia sp., Lasioglossum albipes, Lipotriches pulchriventris et le Formicidae (1 sp.)] et pollinisateurs occasionnels. La comparaison des rendements des fleurs non protégées à celui des fleurs protégées des insectes ont montré que les insectes ont un impact positif sur ce rendement. L’influence de ces insectes est estimée à 9,57%, 7,18% et 4,34% pour le taux de fructification, le nombre de graines/capsule et le pourcentage de graines normales respectivement. Afin d’améliorer le rendement de A. esculentus, il est conseillé de préserver les insectes floricoles non nuisibles dans les champs de gombo en évitant les traitements aux pesticides pendant la période de floraison lorsqu’ils ne se justifient pas. ABSTRACT To determine the species richness, the relative frequency, desired food products, the pollinating insects and impact of these insects on the yields, two treatments were formed from the marking of 240 flower buds in 2015 and 2017, differentiated according to the presence or absence of protection against insect’s activities. Observations were made on free-pollinated Abelmoschus esculentus flowers from 11 to 22 September 2015 and from 7 to 19 September 2017 in Wourndé and Palar respectively. The specific diversity of the flowering insects of okra was 17 and 20 species respectively in Wourndé and Palar. The Jacard index (J = 0.15) reveals a similarity between the two sites, proof that the environmental conditions are similar in both habitats. The insects foraged the flowers of the okra from 8h to 13h, with the peak of the activity of the set of visits of them located between 10 h and 11 h. The insects developed a much elaborated behaviour during the harvest of the nectar and / or the pollen and the consumption of petal. These insects can be grouped into major pollinators (Lipotriches collaris), minor pollinators [Sphecodes albilabris, Camponotus flavomarginatus, Vespidae (1 sp.), Lasioglossum albilabris, Seladonia sp., Lasioglossum albipes, Lipotriches pulchriventris and Formicidae (1 sp.)).] and occasional pollinators. By comparing the yield of unprotected flowers to that of insect-protected flowers, it appeared that insects have a positive impact on this yield. The influence of these insects is estimated at 9.57 %, 7.18 % and 4.34 % for the fruiting rate, the number of seeds / capsule and the percentage of normal seeds respectively. To improve the yield of A. esculentus, it is advisable to preserve the flower-dwelling insects in okra fields by avoiding pesticide treatments during the flowering period when they are not justified.

scholarly journals Using Biogeography to Assess Key Adaptation Strength in Two Bird Families

2017 ◽  
Author(s):  
Abdel H. Halloway ◽  
Christopher J. Whelan ◽  
Çağan H. Şekercioğlu ◽  
Joel S. Brown
Keyword(s):  
Species Richness ◽  
Environmental Conditions ◽  
New World ◽  
Extreme Environments ◽  
The Other ◽  
Latitudinal Gradients ◽  
Old World ◽  
Extended Range

AbstractAdaptations can be thought of as evolutionary technologies which allow an organism to exploit environments. Among convergent taxa, adaptations may be largely equivalent with the taxa operating in a similar set of environmental conditions, divergent with the taxa operating in different sets of environmental conditions, or superior with one taxon operating within an extended range of environmental conditions than the other. With this framework in mind, we sought to characterize the adaptations of two convergent nectarivorous bird families, the New World hummingbirds (Trochilidae) and Old World sunbirds (Nectariniidae), by comparing their biogeography. Looking at their elevational and latitudinal gradients, hummingbirds not only extend into but also maintain species richness in more extreme environments. We suspect that hummingbirds have a superior key adaptation that sunbirds lack, namely a musculoskeletal architecture that allows for hovering. Through biogeographic comparisons, we have been able to assess and understand adaptations as evolutionary technologies among two convergent bird families, a process that should work for most taxa.

How does the taxonomic status of allopatric populations influence species richness within African cichlid fish assemblages?

2003 ◽  
Vol 31 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Martin J. Genner ◽  
Ole Seehausen ◽  
Daniel F.R. Cleary ◽  
Mairi E. Knight ◽  
Ellinor Michel ◽  
...  
Keyword(s):  
Species Richness ◽  
Fish Assemblages ◽  
Cichlid Fish ◽  
Taxonomic Status ◽  
African Cichlid ◽  
Allopatric Populations

Relation between species richness and stream slope in riffle fish assemblages is dependent on spatial scale

2016 ◽  
Vol 99 (8-9) ◽  
pp. 603-612 ◽  
Author(s):  
Mateus Camana ◽  
Renato Bolson Dala-Corte ◽  
Fernando Gertum Becker
Keyword(s):  
Species Richness ◽  
Spatial Scale ◽  
Fish Assemblages

Effects of Urbanization on Stream Ecosystems

2005 ◽  
Keyword(s):  
Species Richness ◽  
Fish Species ◽  
Endemic Species ◽  
Largemouth Bass ◽  
Fish Assemblage ◽  
Life Histories ◽  
Fish Assemblages ◽  
Habitat Alterations ◽  
Intensity Index ◽  
Specialist Species

<em>Abstract.</em>—We examined fish assemblage responses to urban intensity gradients in two contrasting metropolitan areas: Birmingham, Alabama (BIR) and Boston, Massachusetts (BOS). Urbanization was quantified by using an urban intensity index (UII) that included multiple stream buffers and basin land uses, human population density, and road density variables. We evaluated fish assemblage responses by using species richness metrics and detrended correspondence analyses (DCA). Fish species richness metrics included total fish species richness, and percentages of endemic species richness, alien species, and fluvial specialist species. Fish species richness decreased significantly with increasing urbanization in BIR (<em>r </em>= –0.82, <EM>P </EM>= 0.001) and BOS (<em>r </em>= –0.48, <EM>P </EM>= 0.008). Percentages of endemic species richness decreased significantly with increasing urbanization only in BIR (<em>r </em>= – 0.71, <EM>P </EM>= 0.001), whereas percentages of fluvial specialist species decreased significantly with increasing urbanization only in BOS (<em>r </em>= –0.56, <EM>P </EM>= 0.002). Our DCA results for BIR indicate that highly urbanized fish assemblages are composed primarily of largescale stoneroller <em>Campostoma oligolepis</em>, largemouth bass <em>Micropterus salmoides</em>, and creek chub <em>Semotilus atromaculatus</em>, whereas the highly urbanized fish assemblages in BOS are dominated by yellow perch <em>Perca flavescens</em>, bluegill <em>Lepomis macrochirus</em>, yellow bullhead <em>Ameiurus natalis</em>, largemouth bass, pumpkinseed <em>L. gibbosus</em>, brown bullhead <em>A. nebulosus</em>, and redfin pickerel <em>Esox americanus</em>. Differences in fish assemblage responses to urbanization between the two areas appear to be related to differences in nutrient enrichment, habitat alterations, and invasive species. Because species richness can increase or decrease with increasing urbanization, a general response model is not applicable. Instead, response models based on species’ life histories, behavior, and autecologies offer greater potential for understanding fish assemblage responses to urbanization.

scholarly journals Seascape context modifies how fish respond to restored oyster reef structures

2019 ◽  
Vol 76 (4) ◽  
pp. 1131-1139 ◽  
Author(s):  
Ben L Gilby ◽  
Andrew D Olds ◽  
Christopher J Henderson ◽  
Nicholas L Ortodossi ◽  
Rod M Connolly ◽  
...  
Keyword(s):  
Species Richness ◽  
Fish Species ◽  
Fish Assemblages ◽  
Oyster Reef ◽  
Pivotal Role ◽  
Oyster Reefs ◽  
Total Abundance ◽  
Fish Recruitment ◽  
Abundance And Diversity ◽  
Species Specific

Abstract The seascape context of coastal ecosystems plays a pivotal role in shaping patterns in fish recruitment, abundance, and diversity. It might also be a principal determinant in structuring the recruitment of fish assemblages to restored habitats, but the trajectories of these relationships require further testing. In this study, we surveyed fish assemblages from 14 restored oyster reefs and 14 control sites in the Noosa River, Queensland, Australia, that differed in the presence or absence of seagrass within 500 m, over four periods using baited cameras. Fish assemblages at oyster reefs differed from those at control sites, with higher species richness (1.4 times) and more individuals of taxa that are harvested by fishers (1.8 times). The presence or absence of seagrass nearby affected the abundance of a key harvestable fish species (yellowfin bream Acanthopagrus australis) on oyster reefs, but not the overall composition of fish assemblages, species richness, or the total abundance of harvestable fishes overall. These findings highlight the importance of considering species-specific patterns in seascape utilization when selecting restoration sites and setting restoration goals, and suggest that the effects of restoration on fish assemblages might be optimized by focusing efforts in prime positions in coastal seascapes.

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