Incorporation of soft-sediment systems into a model of marine benthic community regulation

1998 ◽  
Vol 49 (8) ◽  
pp. 817 ◽  
Author(s):  
R. D. Seitz
Keyword(s):  
Interspecific Competition ◽  
Resource Availability ◽  
Trophic Position ◽  
Harsh Environments ◽  
Soft Sediment ◽  
Stress Model ◽  
Relative Importance ◽  
Potential Utility ◽  
Physical Disturbance ◽  
Community Regulation

This review (1) describes important regulating forces in soft-sediment systems, (2) outlines existing models of community regulation, and (3) revises a model of community regulation to incorporate soft-sediment systems. The Menge and Sutherland (MS) model of community regulation and its refinements were developed for hard-bottom habitats, but can be modified for soft-sediment systems. This ‘consumer stress model’ posits that mobile consumers feed ineffectively in harsh environments, and that the relative importance of physical disturbance, interspecific competition and predation varies predictably with the magnitude of recruitment, environmental conditions, productivity and trophic position. The MS model predicts that interspecific competition for a resource depends directly upon the level of recruitment, though it does not explicitly address the joint effects of recruitment and resource availability, which are important in soft-sediment communities. The model is here revised to incorporate hard-bottom and soft-sediment systems by changing the recruitment axis to a ‘recruitment:resource ratio’, whereby the effect of a given level of recruitment depends on resource availability. The potential utility of the revised model is illustrated in a hypothetical contrast of the effect of recruitment:resource ratios on community regulation for a mussel-dominated assemblage in hard-bottom habitats and an infaunal clam-dominated system in soft sediments.

scholarly journals Trophic Trait Evolution Explains Variation in Nutrient Excretion Stoichiometry among Panamanian Armored Catfishes (Loricariidae)

Diversity ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 88
Author(s):  
Eric K. Moody ◽  
Fernando Alda ◽  
Krista A. Capps ◽  
Oscar Puebla ◽  
Benjamin L. Turner
Keyword(s):  
Significant Variation ◽  
Trophic Position ◽  
Nutrient Recycling ◽  
Trophic Niche ◽  
Relative Importance ◽  
Closely Related Species ◽  
Trait Evolution ◽  
Nutrient Excretion ◽  
Nutrient Mineralization ◽  
Excretion Rates

Variation in nutrient excretion rates and stoichiometric ratios (e.g., nitrogen to phosphorus) by consumers can have substantial effects on aquatic ecosystem function. While phylogenetic signals within an assemblage often explain variation in nutrient recycling rates and stoichiometry, the phylogenetically conserved traits that underlie this phenomenon remain unclear. In particular, variation in nutrient excretion stoichiometry across a phylogeny might be driven by phylogenetic patterns in either diet or body stoichiometry. We examined the relative importance of these traits in explaining variation in nutrient recycling rates and stoichiometry in a diverse family of Neotropical-armored catfishes, Loricariidae, in Panamanian streams. We found significant variation in nutrient mineralization traits among species and subfamilies, but variation in nutrient excretion stoichiometry among species was best explained by trophic position rather than body stoichiometry. The variation in trophic position among Panamanian species was consistent with variation in the trophic niche of their genera across South America, suggesting that phylogenetic patterns underpin the evolution of trophic and nutrient excretion traits among these species. Such geographical variation in nutrient mineralization patterns among closely related species may be common, given that trophic variation in fish lineages occurs widely. These results suggest that information on trophic trait evolution within lineages will advance our understanding of the functional contribution of animals to biogeochemical cycling.

Resource matching across habitats is limited by competition at patch scales in an estuarine-opportunist fish

2005 ◽  
Vol 62 (4) ◽  
pp. 913-924 ◽  
Author(s):  
Karl M Polivka
Keyword(s):  
Interspecific Competition ◽  
Resource Availability ◽  
Large Scale ◽  
Substantial Reduction ◽  
Fish Growth ◽  
Matching Theory ◽  
Temporal Scales ◽  
Specific Effects ◽  
Resource Matching ◽  
Number Of Individuals

I used field observations, assays, and experiments with the euryhaline cottid Cottus aleuticus to evaluate the extent to which average resource availability drives the large-scale distribution of these fish among upstream and estuarine habitats and how interspecific competition from a congener affects its performance in the estuary. Population densities of C. aleuticus were only consistent with resource densities across years during two of five study years, indicating a lack of resource matching at large temporal scales. On shorter temporal scales, fish growth rates that were two to three times higher in the estuary compared with the stream were inconsistent with the predictions of resource matching theory. A manipulation of C. aleuticus density showed that the estuary could support at least twice the number of individuals that occurred there; thus, the profitable estuary is underutilized. Interspecific competition with Cottus asper was partially responsible for this underutilization as indicated by a substantial reduction in growth and condition among C. aleuticus individuals in experimental manipulations that compared intra- and inter-specific effects. Observed spatial overlap between these two cottids combined with the results of the competition experiment suggests that C. aleuticus is more strongly limited in its ability to use estuarine habitats opportunistically by interspecific competition than by intraspecific competition.

scholarly journals What Drives Life-History Variation in the Livebearing Fish Poeciliopsis prolifica? An Assessment of Multiple Putative Selective Agents

2021 ◽  
Vol 8 ◽  
Author(s):  
Andrea J. Roth-Monzón ◽  
Mark C. Belk ◽  
J. Jaime Zúñiga-Vega ◽  
Jerald B. Johnson
Keyword(s):  
Life History ◽  
Population Density ◽  
Interspecific Competition ◽  
Resource Availability ◽  
Life History Traits ◽  
Life History Evolution ◽  
Embryo Size ◽  
Selective Pressures ◽  
Selective Agents ◽  
Livebearing Fish

Life-history traits are directly linked to fitness, and therefore, can be highly adaptive. Livebearers have been used as models for understanding the evolution of life histories due to their wide diversity in these traits. Several different selective pressures, including population density, predation, and resource levels, can shape life-history traits. However, these selective pressures are usually considered independently in livebearers and we lack a clear understanding of how they interact in shaping life-history evolution. Furthermore, selective pressures such as interspecific competition are rarely considered as drivers of life-history evolution in poeciliids. Here we test the simultaneous effects of several potential selective pressures on life-history traits in the livebearing fish Poeciliopsis prolifica. We employ a multi-model inference approach. We focus on four known agents of selection: resource availability, stream velocity, population density, and interspecific competition, and their effect on four life-history traits: reproductive allocation, superfetation, number of embryos, and individual embryo size. We found that models with population density and interspecific competition alone were strongly supported in our data and, hence, indicated that these two factors are the most important selective agents for most life-history traits, except for embryo size. When population density and interspecific competition increase there is an increase in each of the three life-history traits (reproductive allocation, superfetation, and number of embryos). For individual embryo size, we found that all single-agent models were equivalent and it was unclear which selective agent best explained variation. We also found that models that included population density and interspecific competition as direct effects were better supported than those that included them as indirect effects through their influence on resource availability. Our study underscores the importance of interspecific competitive interactions on shaping life-history traits and suggests that these interactions should be considered in future life-history studies.

Recovery of soft sediment communities and habitats following physical disturbance

2003 ◽  
Vol 285-286 ◽  
pp. 415-434 ◽  
Author(s):  
K.M Dernie ◽  
M.J Kaiser ◽  
E.A Richardson ◽  
R.M Warwick
Keyword(s):  
Soft Sediment ◽  
Physical Disturbance

Feeding ecology of the piked spurdog Squalus megalops (Chondrichthyes: Squalidae) in the Gulf of Gabès (central Mediterranean Sea)

2018 ◽  
Vol 69 (1) ◽  
pp. 48
Author(s):  
Sondes Marouani ◽  
Hasna Kadri ◽  
Sami Karaa ◽  
Mohamed Nejmeddine Bradai
Keyword(s):  
Feeding Ecology ◽  
Trophic Position ◽  
Stomach Contents ◽  
Size Class ◽  
Relative Importance ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Index Of Relative Importance ◽  
Three Factor

The present study investigated the feeding ecology of the piked spurdog (Squalus megalops) in the Gulf of Gabès (Tunisia) with regard to sex, size class and season. A study of stomach contents from the 630 individuals examined showed that the species consumed teleosts (percentage index of relative importance (%IRI)=80.32), cephalopods (%IRI=11.96) and crustaceans (%IRI=7.68). A three-factor multivariate analysis of variance (MANOVA) demonstrated significant differences in diet related to size, season and sex. Trophic position analysis revealed that S. megalops is a secondary consumer throughout its life. Quantitative analysis indicated that the species is a generalist feeder with an ontogenetic change in preferred prey from crustaceans to teleosts. The niche breadths of S. megalops in both sexes were broad.

scholarly journals Differential effects of conspecific and heterospecific density on the development of Aedes aegypti and Aedes albopictus larvae

2018 ◽  
Author(s):  
Robert S Paton ◽  
Katherine Heath ◽  
Anthony J Wilson ◽  
Michael B Bonsall
Keyword(s):  
Aedes Aegypti ◽  
Interspecific Competition ◽  
Resource Availability ◽  
Larval Density ◽  
Single Species ◽  
List Type ◽  
Contest Competition ◽  
Species Competition ◽  
Demographic Stochasticity ◽  
Successful Development

AbstractBetween-species competition shapes the distribution and abundance of populations. Aedes aegypti and Ae. albopictus are vectors of pathogens such as dengue and are known to compete at the larval stage.The outcome of this inter-species competition has been found to be context dependent, with the strength and direction changing with resource availability and type. We were motivated by this uncertainty, and aimed to elucidate the magnitude and mechanism of competition.We manipulated the larval density of mixed and single species cohorts of larvae, measuring the effects on survivorship and development time. Unlike other related studies, we adjusted the feeding regime so that the per-capita resource availability was kept constant across all density treatments, at a level sufficient for successful development. This ensured that each larvae at least had the opportunity to gain the requisite resources for pupation.Our analysis found that Ae. aegypti suffered notably less mortality due to intra- and interspecific competition. For both species, intra- and interspecific competition led to the survival of faster developing individuals, with the exception that slower developing Ae. albopictus larvae survived when exposed a combination of both high con- and heterospecific densities.These results show that the competition between Ae. aegypti and Ae. albopictus can still occur even when resources are theoretically adequate for development. This suggests that larvae can alter resource seeking and consumption parameters when exposed to high densities of conspecifics and heterospecifics, leading to contest competition. Evidence for resource-independent mechanisms of competition such as crowding are also found, as is evidence for the importance of demographic stochasticity in population processes.

Sign in / Sign up

Export Citation Format

Share Document