scholarly journals Differences in the macrozoobenthic fauna colonising empty bivalve shells before and after invasion by Corbicula fluminea

2015 ◽  
Vol 66 (6) ◽  
pp. 549 ◽  
Author(s):  
M. I. Ilarri ◽  
A. T. Souza ◽  
V. Modesto ◽  
L. Guilhermino ◽  
R. Sousa
Keyword(s):  
Species Richness ◽  
Native Species ◽  
Benthic Communities ◽  
Corbicula Fluminea ◽  
Freshwater Bivalve ◽  
Before And After ◽  
Size And Morphology ◽  
Density And Biomass ◽  
Macrozoobenthic Community ◽  
Bivalve Shells

Bivalve shells can potentially alter the structure of aquatic benthic communities. However, little is known about the effect that different shell morphologies have on their associated fauna. This study aimed to understand how empty shells, from four different freshwater bivalve species, affect macrozoobenthic communities, using the River Minho (Iberian Peninsula) as a study area. Three native (Anodonta anatina, Potomida littoralis, Unio delphinus) and one non-indigenous (Corbicula fluminea) species were used for this research. Comparisons among species and between scenarios (i.e. before and after invasion by C. fluminea) were performed. Our results suggest that macrozoobenthic community structure did not vary among treatments, with the exception of species richness, which was higher on shells of native species. Furthermore, little difference was detected when comparing scenarios with and without C. fluminea shells, despite dissimilarities in size and morphology between species. The empty shells of C. fluminea partially (in terms of density and biomass, but not in species richness) replaced the role of empty shells of native species as a physical substratum for the associated macrozoobenthic community.

scholarly journals The influence of fish cage culture on δ13C and δ15N of filter-feeding Bivalvia (Mollusca)

2013 ◽  
Vol 73 (4) ◽  
pp. 743-746
Author(s):  
E. Benedito ◽  
L. Figueroa ◽  
A.M Takeda ◽  
GI. Manetta
Keyword(s):  
Food Web ◽  
Native Species ◽  
Corbicula Fluminea ◽  
Cage Culture ◽  
Aquatic Food Web ◽  
Δ13c And Δ15n ◽  
Value Analysis ◽  
Fine Powders ◽  
Before And After ◽  
Aquatic Food

The objective of this study was to evaluate the effect of Oreochromis niloticus cage culture promoted variations in the δ13C and δ15N in Corbicula fluminea (Mollusca; Bivalvia) and in the sediment of an aquatic food web. Samples were taken before and after net cage installation in the Rosana Reservoir (Paranapanema River, PR-SP). Samples of specimens of the bivalve filterer C. fluminea and samples of sediment were collected using a modified Petersen grab. All samples were dried in an oven (60 °C) for 72 hours, macerated to obtain homogenous fine powders and sent for carbon (δ13C) and nitrogen (δ15N) isotopic value analysis in a mass spectrometer. There were significant differences in the δ13C and δ15N values of the invertebrate C. fluminea between the beginning and the end of the experiment. There were no differences between the δ13C and δ15N values of sediment. These results indicate that the installation of fish cage culture promoted impacts in the isotopic composition of the aquatic food web organisms, which could exert influence over the native species and the ecosystem.

Evaluating the efficacy of removal treatments on wavyleaf basketgrass (Oplismenus undulatifolius)

2020 ◽  
Vol 13 (3) ◽  
pp. 176-188
Author(s):  
Anna K. M. Bowen ◽  
Vanessa B. Beauchamp ◽  
Martin H. H. Stevens
Keyword(s):  
Species Richness ◽  
Native Species ◽  
Invasive Plant ◽  
Percent Cover ◽  
Ecosystem Recovery ◽  
Advantages And Disadvantages ◽  
Hand Weeding ◽  
Density And Biomass ◽  
Native Species Richness ◽  
Wavyleaf Basketgrass

AbstractWith the spread of a new invasive plant species, it is vital to determine the effectiveness of removal strategies as well as their advantages and disadvantages before attempting widespread removal. While thousands of dollars have been spent to curtail the spread of wavyleaf basketgrass [Oplismenus undulatifolius (Ard.) P. Beauv.], a relatively new invasive species, the lack of a cohesive management plan and funding has made controlling this species especially difficult. We assessed the efficacy of a variety of chemical control methods and hand weeding for this species and followed select methods over time. We also assessed the potential for ecosystem recovery following removal by measuring total and native species richness in response to treatments. Our pilot study revealed a wide breadth of responses to our eight herbicides, with fluazifop plus fenoxaprop, imazapic, quizalofop, and sulfometuron methyl being the least effective. In our follow-up experiments, hand weeding, glyphosate, and clethodim treatments were effective at reducing O. undulatifolius percent cover, density, and biomass, with an average reduction of at least 48% in the first year. However, we found substantial variation in the effectiveness of clethodim between our two experiments, which was likely driven by site differences. We also found that all three of these removal methods were effective at reducing the number of O. undulatifolius flowering stems and the height of those stems, which will likely reduce the spread of this species to new areas. Finally, we found that these methods have the potential to restore total and native species richness, but that glyphosate-treated plots did not fully recover until 2 yr after treatment.

Ecological improvement by restoration on the Jialu River: water quality, species richness and distribution

2020 ◽  
Vol 71 (12) ◽  
pp. 1602 ◽  
Author(s):  
Xiangshi Kong ◽  
Kai Tian ◽  
Yanyan Jia ◽  
Zaihua He ◽  
Siyuan Song ◽  
...  
Keyword(s):  
Water Quality ◽  
Species Richness ◽  
Native Species ◽  
Oxygen Demand ◽  
Distribution Patterns ◽  
Ammonium Nitrogen ◽  
Space And Time ◽  
Before And After ◽  
Water Quality Deterioration ◽  
Ecological Improvement

The Jialu River has experienced serious water quality deterioration and biodiversity decline. An ecological restoration project was undertaken. We investigated water quality, species richness and distribution before and after restoration to describe ecological improvements on the Jialu River. After the project, total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD) and ammonium nitrogen (NH4+-N) decreased by 38.69, 40.52, 39.06 and 45.07% respectively. Concentrations of these indices were maintained at steady levels after restoration, indicating stable purification capacity had been established. However, TN, TP and NH4+-N concentrations were still higher than Level V of the Chinese surface water standards. In all, 155 species, belonging to 94 families, were found, with shore plants accounting for the largest proportion (26.53%). The biota showed different distribution patterns over space and time, except for species of zooplankton and phytoplankton, which were evenly distributed over space and time. Most species (71.71%) occurred in only one or two sites. Compared with July 2013, by July 2015 species richness had increased, on average, 65.61%. Furthermore, 31 novel native species were found in July 2015, covering the main functional groups (hydrophytes, zoobenthos and fishes). The recovery of an intact food chain as a result of the project facilitated water purification in the short term and the return of birds to the Jialu River in the long term. This study evaluated the recovery of the Jialu River and the results will inform future ecosystem restoration projects.

Partial cutting reduces species richness of fungi on woody debris in oak-rich forests

2008 ◽  
Vol 38 (7) ◽  
pp. 1807-1816 ◽  
Author(s):  
Björn Nordén ◽  
Frank Götmark ◽  
Martin Ryberg ◽  
Heidi Paltto ◽  
Johan Allmér
Keyword(s):  
Species Richness ◽  
Woody Debris ◽  
Basal Area ◽  
Fruiting Bodies ◽  
Partial Cutting ◽  
Total Species Richness ◽  
Before And After ◽  
Closed Canopy ◽  
And Control ◽  
Total Species

Partial cutting is increasingly applied in European temperate oak-dominated forests for biofuel harvesting, and to counteract succession in protected stands. Effects on biodiversity of these measures need to be carefully evaluated, and species-rich but neglected taxa such as fungi should be considered. We studied the effects of partial cutting on fungal fruiting bodies on woody debris. In 21 closed canopy forests rich in large oaks in Sweden, on average 25%–30% of the basal area was cut. Fruiting bodies were counted and some were collected in treated and control plots before and after treatment. We found 334 basidiomycete and 47 ascomycete species. Species richness of basidiomycetes declined significantly more in treated plots (on average 26%) than in control plots (on average 13%) between seasons. Species richness of ascomycetes increased by 17% in control plots and decreased by 2% in treated plots. Total species richness was significantly reduced on fine woody debris (1–10 cm in diameter), but not on coarse woody debris (>10 cm). Overall species composition did not change significantly as a result of partial cutting, but red-listed species tended to decrease more in treated plots. We suggest that approximately 30% of the stands should not be thinned, and dead stems and fallen branches should not be removed, to favor saproxylic fungi and their associated fauna.

Detonation Consolidation of NiFe/SiO2 and Co/SiO2 nanocomposites

2002 ◽  
Vol 759 ◽  
Author(s):  
Xinqing Ma ◽  
Y. D. Zhang ◽  
S. Hui ◽  
Mingzhong Wu ◽  
Shihui Ge ◽  
...  
Keyword(s):  
Magnetic Particles ◽  
Oxygen Mixture ◽  
Full Density ◽  
Magnetic Studies ◽  
Powder Morphology ◽  
Hypersonic Propulsion ◽  
Operation Conditions ◽  
Before And After ◽  
Propulsion Force ◽  
Size And Morphology

ABSTRACTConsolidation of nanostructure magnetic particles is required not only for manufacturing bulk component, it is actually a fundamental requirement for obtaining novel magnetic properties from the material. Consolidation (assembly) of nanoparticles to full density without deteriorating their nanostructure (size and morphology) is a big challenge. Here we present the consolidation experiments of NiFe/SiO2 and Co/SiO2 nanocomposites via detonation consolidation. This approach is based on the explosive pressure created when an acetylene and oxygen mixture gas fires in a sample containing tube, the very high hypersonic propulsion force makes nanoparticles deposit onto the target. Depending on the powder morphology and operation conditions, the density of the consolidated sample can reach over 91% of the theoretical density of the bulk materials. X-ray diffraction experiments on the samples before and after consolidation indicate that the denotation consolidations can be optimized such that it does not cause any phase transition. However, a particle size increase was observed. Static magnetic studies carried out on the samples before and after detonation operation shows that the saturation magnetization does not. This indicates that the operation does not cause an oxidation of the nanopowders. These experiments show that detonation approach is a good candidate for consolidating magnetic nanoparticles.

scholarly journals Habitat, food, and small mammal community structure in Namaqualand

Koedoe ◽  
2006 ◽  
Vol 49 (1) ◽  
Author(s):  
M. Van Deventer ◽  
J.A.J. Nel
Keyword(s):  
Species Richness ◽  
Food Availability ◽  
Small Mammal ◽  
Plant Cover ◽  
Plant Litter ◽  
Shrub Cover ◽  
Habitat Features ◽  
Habitat Differences ◽  
Elephant Shrew ◽  
Density And Biomass

The effect of habitat differences and food availability on small mammal (rodent and elephant shrew) species richness, diversity, density and biomass was investigated in Namaqualand, South Africa. Species richness in the three habitats sampled, namely Upland Succulent Karoo, Dry Riverine Shrub and North-western Mountain Renosterveld was low, with only 2–4 species per habitat. Rodents trapped were predominantly Gerbillurus paeba and Aethomys namaquensis, with fewer Mus minutoides and Petromyscus sp. The only non-rodent was the elephant shrew Elephantulus edwardii. Ten habitat features, the percentage of total plant cover, tree cover, shrub cover, grass cover, plant litter, total basal cover, sand, gravel or rock cover, and the dominant plant height were recorded at 30 randomly chosen points on five sampling grids in each habitat. Small mammal density and biomass was significantly correlated with food availability (green foliage cover, seeds, and relative density and biomass of insects). Species richness and diversity of small mammals were significantly correlated with shrub cover. Numbers and biomass of specific species correlated significantly with different habitat features in each case.

scholarly journals Impacts of non-native Norway spruce plantation on abundance and species richness of ground beetles (Coleoptera: Carabidae)

Web Ecology ◽  
2001 ◽  
Vol 2 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Z. Elek ◽  
T. Magura ◽  
T. Tóthmérész
Keyword(s):  
Species Richness ◽  
Norway Spruce ◽  
Native Species ◽  
Detrimental Effect ◽  
Deciduous Forest ◽  
Management Practice ◽  
Beech Forest ◽  
Nature Management ◽  
Native Forest ◽  
Active Nature

Abstract. The impacts of non-native Norway spruce plantation on the abundance and species richness of carabids were studied in the Bükk National Park in Hungary, central Europe. Pitfall catches from recently established (5 yr old), young (15 yr after planting), middle-aged (30 yr after planting), old Norway spruce Picea abies plantation (50 yr after planting), and a native submontane beech forest (Fagetum sylvaticae) as a control stand were compared. Our results showed that deciduous forest species decreased significantly in abundance in the plantations, and appeared in high abundance only in the native beech forest. Furthermore, open habitat species increased remarkably in abundance in the recently established plantation. Carabids were significantly more abundant and species rich in the native forest than in the plantations, while differences were not significant among the plantations. Multiple regression between the abundance and species richness of carabids and twelve environmental measurements showed that pH of the soil, herb cover and density of the carabids’ prey had a significant effect in determining abundance and species richness. Our results showed that plantation of non-native Norway spruce species had a detrimental effect on the composition of carabid communities and no regeneration could be observed during the growth of plantations even 50 yr after the establishment. This emphasises the importance of an active nature management practice to facilitate the recolonization of the native species.

scholarly journals Heavy metals concentration in “etak” tissue at different processing stages.

2019 ◽  
Vol 7 (1) ◽  
pp. 36-39
Author(s):  
Dee Koh Han ◽  
Faizuan Abdullah ◽  
Idanne Adilla Ibrahim ◽  
Nurul Inani Rozaki ◽  
Siti Nor Aini Md Nasir ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Corbicula Fluminea ◽  
Atomic Absorption Spectrometer ◽  
Acid Digestion ◽  
Sample Collection ◽  
Freshwater Bivalve ◽  
Metal Determination ◽  
Permissible Limits ◽  
Local Newspapers ◽  
Heavy Metal Determination

Corbicula fluminea, known as “etak” in Kelantan, Malaysia is a freshwater bivalve. This clam is widely consumed as traditional snack by the locals. However, lately there are numerous reports in local newspapers that claim “etak” to cause health effects due to eating contaminated “etak”. Hence, this study aims to determine the heavy metals concentration in fresh, smoked and exposed “etak” sold at the stall as a baseline study in order to develop a method for removing the heavy metals content in its tissues. This study involves sample collection in the stalls around Kelantan, sample preparations via acid digestion and heavy metal determination using Perkin Elmer PinAAcle 900F Atomic Absorption Spectrometer. The results showed the heavy metals (Cr, Zn, Mn and Cu) concentrations (µg/g) in all “etak” tissue were at different level for fresh (Cr: 1.02±0.35ppm, Zn: 74.57±2.76ppm, Mn: 40.22±9.96ppm and Cu: 15.27±1.41ppm), smoked (Cr: 0.42±0.02ppm, Zn: 54.62±17.83ppm, Mn: 50.13±2.31ppm and Cu: 20.94±8.81ppm) and exposed (Cr: 0.53±0.08ppm, Zn: 63.07±8.44ppm, Mn: 50.41±6.92ppm and Cu: 12.80±0.40ppm) samples. The results obtained were compared with the permissible limits set by Malaysian Food Regulations 1985 (Cu: 30.0ppm and Zn: 100.0ppm), FAO/WHO 1984 (Mn: 5.4ppm) and IAEA – 407 (Cr: 0.75ppm). For fresh “etak”, Zn and Cu concentration were below the standards, while Mn and Cr were exceeded the permissible limits. For smoked “etak” and exposed “etak” at stall, all heavy metals concentration were within the permissible limits, except Mn contents. This study successfully determine the baseline concentration of the heavy metals in “etak”.

scholarly journals Influence of chemosynthetic ecosystems on nematode community structure and biomass in the deep eastern Mediterranean Sea

2012 ◽  
Vol 9 (12) ◽  
pp. 18131-18173
Author(s):  
N. Lampadariou ◽  
V. Kalogeropoulou ◽  
K. Sevastou ◽  
K. Keklikoglou ◽  
J. Sarrazin
Keyword(s):  
Species Richness ◽  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Nematode Community ◽  
Cold Seep ◽  
Mud Volcanoes ◽  
Mussel Bed ◽  
Remotely Operated Vehicle ◽  
Eastern Mediterranean Sea ◽  
Density And Biomass

Abstract. Mud volcanoes are a special type of cold seeps where life is based on chemoautotrophic processes. They are considered as extreme environments and are characterised by unique megafaunal and macrofaunal communities. However, very few studies on mud volcanoes taking into account the smaller meiobenthic communities have been carried out. Two mud volcanoes were explored during the MEDECO cruise (2007) with the Remotely Operated Vehicle (ROV) Victor-6000; Amsterdam, located south of Turkey between 1700 and 2000 m depth (Anaximander mud field) and Napoli, south of Crete, located along the Mediterranean Ridge at about 2000 m depth (Olimpi mud field). The major aim of this study was to describe distributional patterns of meiofaunal communities and nematode assemblages from different seep microhabitats. Meiofaunal taxa and nematode assemblages at both mud volcanoes differed significantly from other Mediterranean sites in terms of standing stocks, dominance and species diversity. Density and biomass values were significantly higher at the seep sites, particularly at Amsterdam. Nematodes, the dominant meiofaunal taxon, displayed deeper penetration vertically into the sediment at the seep areas, indicating that biological rather than physicochemical factors are responsible for their vertical distribution. Patterns of nematode diversity varied, displaying both very high or very low species richness and dominance, depending on the habitat studied. The Lamellibrachia periphery and mussel bed of Napoli exhibited the highest species richness while the reduced sediments of Amsterdam yielded a species-poor nematode community, dominated by two successful species; one belonging to the genus Aponema and the other to the genus Sabatieria. Analysis of β-diversity showed that habitat heterogeneity of mud volcanoes contributed substantially to the total nematode species richness in the eastern Mediterranean Sea. These observations indicate a strong influence of mud volcanoes and cold-seep ecosystems on the meiofaunal communities and nematode assemblages.

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