Competition between Brachionus calyciflorus and Brachionus angularis (Rotifera) in relation to algal food level and initial population density

2019 ◽  
Vol 55 ◽  
pp. 2
Author(s):  
Kun Zhang ◽  
Quan Wan ◽  
Yi-Long Xi
Keyword(s):  
Zooplankton Community ◽  
Limited Resource ◽  
Brachionus Calyciflorus ◽  
Food Level ◽  
Initial Population ◽  
High Food ◽  
Initial Population Density ◽  
Population Growth Rates ◽  
Peak Abundance ◽  
Brachionus Angularis

Intensive interspecific competition for limited resource often can result in the exclusion of inferior competitors, decrease the species diversity and alter the structure of the zooplankton community. Competitive experiments between Brachionus calyciflorus and Brachionus angularis were conducted at three Scenedesmus densities (0.5 × 106, 1.0 × 106 and 2.0 × 106 cells ml−1) and four initial inoculation densities (numerically, 100% B. calyciflorus, 75% B. calyciflorus and 25% B. angularis, 50% each of the two species, 25% B. calyciflorus and 75% B. angularis, and 100% B. angularis). The results showed that at the low food level, B. angularis outcompeted B. calyciflorus and vice versa at the high food levels. At the intermediate food level, B. angularis was displaced by B. calyciflorus at nearly all the initial inoculation densities except for 75% B. angularis, at which both species coexisted until the termination of the experiment. When grown alone at 0.5 × 106, 1.0 × 106 and 2.0 × 106 cells ml−1 of Scenedesmus, B. calyciflorus reached the peak abundance values of 34 ± 4, 69 ± 5 and 101 ± 9 individuals ml−1 and had population growth rates of 0.608 ± 0.032, 0.654 ± 0.033 and 0.518 ± 0.039 d−1, respectively. The corresponding values for B. angularis were 265 ± 8, 330 ± 30 and 802 ± 87 individuals ml−1 and 0.623 ± 0.020, 0.770 ± 0.036 and 0.871 ± 0.013 d−1. The results suggest that the outcome of competition depends not only on the size of the competing species and food availability but also on their colonizing density.

The diversity and longitudinal changes of zooplankton in the lower course of a large, regulated European river (the lower Vistula River, Poland)

Biologia ◽  
2013 ◽  
Vol 68 (6) ◽  
Author(s):  
Paweł Napiórkowski ◽  
Teresa Napiórkowska
Keyword(s):  
Species Diversity ◽  
Zooplankton Community ◽  
Abundant Species ◽  
Main Channel ◽  
Brachionus Calyciflorus ◽  
Longitudinal Variation ◽  
Zooplankton Species ◽  
Larval Stages ◽  
Vistula River ◽  
Brachionus Angularis

AbstractThe diversity and longitudinal variation of zooplankton in the lower Vistula River were analyzed. Samples were taken from 40 stations located along a 272-km long section of the lower river course. During the study the unique technique of taking samples from “the same water” was used. The zooplankton community was dominated by rotifers and nauplii — larval stages of copepods. The most abundant species were: Brachionus angularis, Brachionus calyciflorus and Brachionus budapestiensis. The zooplankton species diversity in the main channel of the lower Vistula River was similar to other large European rivers; however, its abundance was lower. The diversity, abundance and biomass of potamoplankton steadily decreased downstream. This could be related both to scarcity of storage zones for potamoplankton development in the river due to the extensive regulation processes, and changes in hydrological conditions of the main channel (by the straightening of riverbed) where the samples were collected.

scholarly journals A theoretical framework for multi-species range expansion in spatially heterogeneous landscapes

2021 ◽  
Author(s):  
Lukas Eigentler ◽  
Nicola R Stanley-Wall ◽  
Fordyce A Davidson
Keyword(s):  
Population Density ◽  
Range Expansion ◽  
Theoretical Framework ◽  
Dominant Mode ◽  
Bacterial Biofilm ◽  
Time Interval ◽  
Initial Population ◽  
Initial Population Density ◽  
Competitive Outcome ◽  
The Impact

Range expansion is the spatial spread of a population into previously unoccupied regions. Understanding range expansion is important for the study and successful manipulation and management of ecosystems, with applications ranging from controlling bacterial biofilm formation in industrial and medical environments to large scale conservation programmes for species undergoing climate-change induced habitat disruption. During range expansion, species typically encounter competitors. Moreover, the environment into which expansion takes place is almost always heterogeneous when considered at the scale of the individual. Despite the ubiquitous nature of these features, the impact of competition and spatial landscape heterogeneities on range expansion remains understudied. In this paper we present a theoretical framework comprising two competing generic species undergoing range expansion and use it to investigate the impact of spatial landscape heterogeneities on range expansion with a particular focus on its effect on competition dynamics. We reveal that the area covered by range expansion during a fixed time interval is highly variable due to the fixed landscape heterogeneities. Moreover, we report significant variability in competitive outcome (relative abundance of a focal species) but determine that this is induced by low initial population densities, independent of landscape heterogeneities. We further show that both area covered by range expansion and competitive outcome can be accurately predicted by a Voronoi tessellation with respect to an appropriate metric, which only requires information on the spatial landscape and the response of each species to that landscape. Finally, we reveal that if species interact antagonistically during range expansion, the dominant mode of competition depends on the initial population density. Antagonistic actions determine competitive outcome if the initial population density is high, but competition for space is the dominant mode of competition if the initial population density is low.

Effect of two microalgae concentrations on body size and egg size of the rotifer Brachionus calyciflorus

Biologia ◽  
2008 ◽  
Vol 63 (3) ◽  
Author(s):  
Abdolmohammad Kennari ◽  
Nasrollah Ahmadifard ◽  
Maryam Kapourchali ◽  
Jafar Seyfabadi
Keyword(s):  
Body Size ◽  
Population Growth ◽  
Egg Size ◽  
Scenedesmus Obliquus ◽  
Exponential Phase ◽  
The Body ◽  
Brachionus Calyciflorus ◽  
Food Level ◽  
Chlorella Sp ◽  
Rotifer Brachionus Calyciflorus

AbstractThe rotifer, Brachionus calyciflorus, was grown with two algae species (Chlorella sp. and Scenedesmus obliquus) at different concentrations (0.1, 1 and 10 × 106 cells ml−1). The body size (lorica biovolume) of individual rotifer and their egg size were measured when the populations were roughly in the exponential phase of population growth. The body size of the rotifers differed significantly (P < 0.05) among the two algae species used, however this effect was not observed for egg size. The body size of rotifers fed on higher densities of Chlorella sp. (10 × 106 cells ml−1) was significantly larger than for those fed on lower and medium densities (0.1 and 1 × 106 cells ml−1). Body size and egg size of rotifers fed with different amounts of Scenedesmus did not differ significantly. The egg size was significantly larger at higher food level of Chlorella. A significantly positive correlation was observed between the adult rotifer body size and their egg size.

The effects of food level on general activity and aggression in dynamic groups of 30 sows

1995 ◽  
Vol 1995 ◽  
pp. 31-31 ◽  
Author(s):  
H.A.M. Spoolder ◽  
J.A. Burbidge ◽  
A.B. Lawrence ◽  
P.H. Simmins ◽  
S.A. Edwards
Keyword(s):  
Skin Lesions ◽  
Food Level ◽  
High Food ◽  
General Activity ◽  
Injury Score ◽  
Feeding Motivation ◽  
Large Groups ◽  
Feeding Systems

Aggression in group housed sows is often related to competition over food. Sequential feeding avoids the confrontations at the trough, but puts them at the feeder entrance. Studies of large groups of dry sows using computerised feeding systems showed that vulva biting was most frequent after visits when only a small amount of food had been dispensed (Buré, 1991). This suggests that frustrated feeding motivation may cause increased aggression. A Swedish survey into group housed sows found a link between sow condition and mean injury scores: farms averaging a high injury score had a larger proportion of thin sows (Svendsen et al., 1990). The present study aimed to investigate the hypothesis that in large dynamic groups of sows a high food level results in lower levels of aggression and associated skin lesions.

scholarly journals Long-term, predation-based control of a central-west North Sea zooplankton community

2003 ◽  
Vol 60 (2) ◽  
pp. 187-197 ◽  
Author(s):  
Robin A Clark ◽  
Chris L.J Frid ◽  
Kirsty R Nicholas
Keyword(s):  
North Sea ◽  
Inverse Relationship ◽  
Climatic Factors ◽  
Zooplankton Community ◽  
Positive Association ◽  
Zooplankton Abundance ◽  
Total Zooplankton ◽  
Population Growth Rates ◽  
North Wall

Abstract Long-term monitoring of the zooplankton community at a station 5.5 miles from the English coast in the central-west North Sea has been performed since 1968. Analyses of these data have revealed an inverse relationship between annual total zooplankton abundance and the position of the Gulf Stream North Wall (GSNW). This long-term relationship is opposite to the long-term positive association observed between the GSNW and total zooplankton abundances throughout most of the oceanic NE Atlantic region and the northern and central North Sea using Continuous Plankton Recorder data. This study investigates the mechanism behind the inverse relationship with the GSNW, focussing on the importance of zooplankton predators in influencing long-term changes in the zooplankton community of the central-west North Sea. The results suggest that the dominant zooplankton predator Sagitta elegans plays a key role in mediating spring copepod population growth rates and thus their maximum and overall productivity during any one particular year. In turn, the abundance of Sagitta during the spring appears to be related to climatic factors. The implications of this on the zooplankton community are discussed.

scholarly journals A Population of Meloidogyne javanica in Spain Virulent to the Mi Resistance Gene in Tomato

Plant Disease ◽  
2001 ◽  
Vol 85 (3) ◽  
pp. 271-276 ◽  
Author(s):  
C. Ornat ◽  
S. Verdejo-Lucas ◽  
F. J. Sorribas
Keyword(s):  
Population Density ◽  
Negative Correlation ◽  
Meloidogyne Javanica ◽  
Initial Population ◽  
Initial Population Density ◽  
Tomato Yield ◽  
Final Population ◽  
Tomato Cultivars ◽  
Mi Gene ◽  
Susceptible Tomato

A population of Meloidogyne javanica virulent to Mi-gene in tomato was identified in Spain. It reproduced similarly on resistant and susceptible tomato cultivars in the greenhouse, microplots, and in the field. In monoxenic cultures, reproduction of the virulent M. javanica was higher than that of an avirulent population on resistant but not on susceptible tomatoes. The virulent population suppressed tomato yield of both resistant and susceptible tomatoes by 29% in microplots. Initial population density (Pi) was inversely correlated with Pf (final population density)/Pi on both resistant and susceptible tomatoes in the field. A negative correlation was found between Pi and tomato yield for the susceptible but not for the resistant cultivar.

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