Evaluating potential competitive interactions following stocking through trophic niche breadth

2018 ◽  
Vol 69 (10) ◽  
pp. 1614 ◽  
Author(s):  
Matthew D. Taylor ◽  
Michael B. Lowry ◽  
Alistair Becker
Keyword(s):  
Stable Isotope ◽  
Niche Breadth ◽  
Environmental Variability ◽  
Mouth Opening ◽  
Trophic Niche ◽  
Competitive Interactions ◽  
Competing Species ◽  
Competitive Effects ◽  
Run Off ◽  
Trophic Overlap

Responsible fisheries enhancement should include comprehensive monitoring programs to detect ecological effects of fish releases and support adaptive management. Competition for food and shelter is one such impact, and density-dependent effects may occur if release numbers are above levels that the ecosystem can support. Herein we present a novel application of trophic niche breadth estimated from stable isotope data to examine potential competitive interactions arising from eastern king prawn (Melicertus plebejus) stocking. Eastern king prawn and potential competitors (Macrobrachium intermedium, Atherinosoma microstoma, Leptatherina presbyteroides, Ambassis jacksoniensis and Gobiopterus semivestitus) were sampled from two stocked and two reference estuaries, before and after stocking. Stable isotope ratios were measured and used to model trophic overlap and trophic niche breadth. A statistically significant increase in niche breadth was evident for two competing species in one stocked estuary, and one competing species in another. M. intermedium, the species that had the greatest trophic overlap with eastern king prawn, did not show any change in niche breadth. The potential for competition and the role of environmental variability (including rainfall and run-off, mouth opening regime and seasonal changes) in driving the patterns observed are discussed. This approach shows promise for monitoring competitive effects arising from aquaculture-based fisheries enhancements in the future.

scholarly journals Trophic ecology of sea urchins in coral-rocky reef systems, Ecuador

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1578 ◽  
Author(s):  
Nancy Cabanillas-Terán ◽  
Peggy Loor-Andrade ◽  
Ruber Rodríguez-Barreras ◽  
Jorge Cortés
Keyword(s):  
Stable Isotope ◽  
Trophic Ecology ◽  
Habitat Degradation ◽  
Sea Urchins ◽  
Relative Proportion ◽  
Isotope Analysis ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Rocky Reef ◽  
Trophic Overlap

Sea urchins are important grazers and influence reef development in the Eastern Tropical Pacific (ETP).Diadema mexicanumandEucidaris thouarsiiare the most important sea urchins on the Ecuadorian coastal reefs. This study provided a trophic scenario for these two species of echinoids in the coral-rocky reef bottoms of the Ecuadorian coast, using stable isotopes. We evaluated the relative proportion of algal resources assimilated, and trophic niche of the two sea urchins in the most southern coral-rocky reefs of the ETP in two sites with different disturbance level. Bayesian models were used to estimate the contribution of algal sources, niche breadth, and trophic overlap between the two species. The sea urchins behaved as opportunistic feeders, although they showed differential resource assimilation.Eucidaris thouarsiiis the dominant species in disturbed environments; likewise, their niche amplitude was broader than that ofD. mexicanumwhen conditions were not optimal. However, there was no niche overlap between the species. The Stable Isotope Analysis in R (SIAR) indicated that both sea urchins shared limiting resources in the disturbed area, mainlyDictyotaspp. (contributions of up to 85% forD. mexicanumand up to 75% forE. thouarsii). The Stable Isotope Bayesian Ellipses in R (SIBER) analysis results indicated less interspecific competition in the undisturbed site. Our results suggested a trophic niche partitioning between sympatric sea urchin species in coastal areas of the ETP, but the limitation of resources could lead to trophic overlap and stronger habitat degradation.

scholarly journals Trophic niche breadth of pond zooplankton species using stable isotope analysis and the relationship with the abiotic and biotic factors

2019 ◽  
Vol 6 (1) ◽  
pp. 180917 ◽  
Author(s):  
Hideyuki Doi ◽  
Kwang-Hyeon Chang ◽  
Shin-ichi Nakano
Keyword(s):  
Stable Isotope ◽  
Niche Breadth ◽  
Resource Competition ◽  
Feeding Habits ◽  
Zooplankton Biomass ◽  
Trophic Niche ◽  
Zooplankton Species ◽  
Carbon And Nitrogen ◽  
Ecosystem Size ◽  
The Relationship

Zooplankton species have different feeding habits, but the diversity of their food resources and the factors governing them are still largely unknown. We here estimated the differences in the trophic niche breadths of dominant zooplankton species in ponds, using stable isotopes. To understand the differences in trophic niches of different zooplankton species, we measured the carbon and nitrogen stable isotope ratios and calculated the nearest-neighbour distance (NND), and standard deviation of NND (SDNND) of the bi-plot space of stable carbon and nitrogen isotopes in pond zooplankton. We tested the relationship between the NND/SDNND and environmental factors, as well as the zooplankton biomass, using generalized linear models (GLMs). For cladocerans, including Bosmina, Ceriodaphnia and Daphnia, the NNDs were significantly correlated with the biomass, pond morphology (volume and depth), total phosphorous (TP) and fish presence. For copepod species, including Eodiaptomus and cyclopoids, NNDs were significantly correlated with pond morphology, TP and fish presence, but not with biomass. In GLMs of SDNND, significant correlated factors were less than those for NND, and for some species, pond morphology and TP were significantly correlated with SDNND. Here, we found that the NND and SDNND of zooplankton species were related to various factors, including their biomass, predator presence, pond size and water quality. For cladocerans, biomass may be supported by trophic niche breadth, probably because of the consequences of resource competition. Also, predation and ecosystem size may influence trophic niche breadth due to changes in zooplankton behaviours.

scholarly journals Feeding habits and dietary overlap during the larval development of two sandperches (Pisces: Pinguipedidae)

2017 ◽  
Vol 81 (2) ◽  
pp. 195 ◽  
Author(s):  
Javier A. Vera-Duarte ◽  
Mauricio F. Landaeta
Keyword(s):  
Niche Breadth ◽  
Feeding Habits ◽  
Mouth Opening ◽  
Trophic Niche ◽  
Dietary Overlap ◽  
Austral Spring ◽  
Larval Size ◽  
Larval Stages ◽  
Nearshore Environments ◽  
Larval Species

Two species of sandperch (Pinguipedidae: Perciformes), Prolatilus jugularis and Pinguipes chilensis, inhabit the coastal waters of the South Pacific. Both species have pelagic larvae with similar morphology, but their diet preferences are unknown. Diet composition, feeding success, trophic niche breadth and dietary overlap were described during larval stages for both species. In the austral spring, larval P. jugularis (3.83-10.80 mm standard length [SL]) and P. chilensis (3.49-7.71 mm SL) during their first month of life had a high feeding incidence ( > 70%) and fed mostly on copepod nauplii ( > 80% IRI), Rhincalanus nasutus metanauplii and Paracalanus indicus copepodites. The number of prey ingested was low (mean: 4-5 prey per gut) and independent of larval size; total prey volume and maximum prey width increased as larvae grew. Mouth opening and ingested prey were greater in larval P. jugularis than in P. chilensis, leading to significant differences in prey composition among larval species, in terms of prey number and volume. Pearre’s trophic niche breadth was narrow for both species (0.159±0.07 for P. jugularis; 0.156±0.03 for P. chilensis) and independent of larval size. Dietary overlap was high inter- and intra-species in larvae with a mouth gape < 900 μm. These results suggest the relative importance of both larval species as primary consumers of the pelagic web in nearshore environments of rocky temperate areas.

scholarly journals Food Web Structure and Trophic Interactions Revealed by Stable Isotope Analysis in the Midstream of the Chishui River, a Tributary of the Yangtze River, China

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 195
Author(s):  
Qiang Qin ◽  
Fubin Zhang ◽  
Fei Liu ◽  
Chunling Wang ◽  
Huanzhang Liu
Keyword(s):  
Stable Isotope ◽  
Carbon Source ◽  
Food Web ◽  
Food Chain ◽  
Yangtze River ◽  
Trophic Niche ◽  
The Yangtze River ◽  
Food Chain Length ◽  
Trophic Pathways ◽  
Chishui River

Understanding energy flow and nutrient pathways is crucial to reveal the dynamics and functions of riverine ecosystems and develop appropriate conservation strategies. In this study, we utilized stable isotopes of δ13C and δ15N to examine the fundamental characteristics of trophic position, trophic niche, and carbon source for the food web in the midstream of the Chishui River, a tributary to the Yangtze River. Our results showed that stable isotope signatures among different sorts of basal resources and consumers were significantly distinguishable and that the food chain consisted of four trophic levels, indicating the multiple trophic pathways and long food chain length here. The trophic guilds of fish were classified into four categories, in which herbivorous and carnivorous fish showed greater trophic diversity and omnivorous fish had higher trophic redundancy, which meant that there was a stable trophic niche structure in the study area. Phytoplankton and periphyton presented the largest contributions to consumers, indicating that autochthonous productivity was the dominant carbon source in the midstream of the Chishui River. Since the Chishui River is still in a natural condition without any dam constructions, the autochthonous productivity, stable trophic niche structure, multiple trophic pathways and long food chain length found here demonstrate its high conservation value. Therefore, the strategy to refrain from damming on this river should persist into the future.

scholarly journals Ecology of colonizing populations of the figfly Zaprionus indianus (Diptera, Drosophilidae) in Porto Alegre, Southern Brazil

2005 ◽  
Vol 95 (3) ◽  
pp. 233-240 ◽  
Author(s):  
Norma Machado da Silva ◽  
Carina da Conceição Fantinel ◽  
Vera Lucia da Silva Valente ◽  
Vitor Hugo Valiati
Keyword(s):  
Niche Breadth ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Survival Strategies ◽  
Porto Alegre ◽  
Zaprionus Indianus ◽  
Feeding Sites ◽  
Substrate Choice ◽  
Oviposition Substrate ◽  
Feeding Substrate

Ecological parameters such as trophic niche overlap and niche breadth were computed from the frequency of all drosophilid species collected in 2001 and 2002, in the urban area of Porto Alegre city, Brazil. Independently of place, drosophilids community composition and components breeding or feeding sites, the highest frequencies of Zaprionus indianus (Gupta, 1970) were obtained during seasons with higher average temperatures, especially during summer. From a total of the 19,146 individuals of Z. indianus sampled, 80% were found in this season. The data of trophic niche breadth suggest a higher opportunism of adult flies in feeding substrate use, but the females are still selective in oviposition substrate choice. For the values of niche overlap, only for some species, did we find any correlation between these and species richness and/or number of resources, and the most of the correlation values considering breeding and feeding sites were positive. The colonization of Z. indianus in Porto Alegre could be leading to adjustments in the survival strategies of the resident species, but it is possible that many species have conditions for coexisting with the invader.

Managing Centrarchid Fisheries in Rivers and Streams

2019 ◽  
Keyword(s):  
Community Structure ◽  
Stable Isotope ◽  
Prey Availability ◽  
Prey Selection ◽  
Trophic Position ◽  
Trophic Niche ◽  
Smallmouth Bass ◽  
Spatial Differences ◽  
Stream Size ◽  
Diet Analyses

<em>Abstract.</em>—Prey selection and diet are highly plastic and can vary with temporal and spatial differences in competition or prey availability. This study investigated the possibility that the trophic position of Smallmouth Bass <em> Micropterus dolomieu </em>might change in response to systematic, hierarchical variation in community structure in stream networks. We hypothesized that a shift toward increased insectivory and decreased piscivory would be observed in smaller streams, resulting in a lower trophic position of Smallmouth Bass and reflecting differences in community structure and prey availability. We applied a combination of diet analyses and stable isotope methods to compare prey selection and trophic position of Smallmouth Bass across a range of stream sizes. Stable isotope analyses indicated that Smallmouth Bass trophic position was slightly elevated in smaller watersheds, contradicting our initial hypothesis. However, differences in average trophic position in watershed size categories were small (ranging from 3.6 to 3.8) and of limited ecological significance. Isotopic niche width did not vary among stream size categories, and gut content analyses revealed no differences in frequency of occurrence of fish, crayfish, or insects (larvae and adults). Collectively these results indicate that trophic position, and perhaps trophic niche, of Smallmouth Bass are consistent across hierarchical variation in stream size and habitat.

scholarly journals Morphology and stable isotope analysis demonstrate different structuring of bat communities in rainforest and savannah habitats

2018 ◽  
Vol 5 (12) ◽  
pp. 180849 ◽  
Author(s):  
Ara Monadjem ◽  
Adam Kane ◽  
Peter Taylor ◽  
Leigh R. Richards ◽  
Grant Hall ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Niche Breadth ◽  
Isotope Analysis ◽  
Morphological Characters ◽  
Trophic Levels ◽  
Species Packing ◽  
Dietary Niche ◽  
The One ◽  
Ellipse Area

Bats play important ecological roles in tropical systems, yet how these communities are structured is still poorly understood. Our study explores the structure of African bat communities using morphological characters to define the morphospace occupied by these bats and stable isotope analysis to define their dietary niche breadth. We compared two communities, one in rainforest (Liberia) and one in savannah (South Africa), and asked whether the greater richness in the rainforest was due to more species ‘packing’ into the same morphospace and trophic space than bats from the savannah, or some other arrangement. In the rainforest, bats occupied a larger area in morphospace and species packing was higher than in the savannah; although this difference disappeared when comparing insectivorous bats only. There were also differences in morphospace occupied by different foraging groups (aerial, edge, clutter and fruitbat). Stable isotope analysis revealed that the range of δ 13 C values was almost double in rainforest than in savannah indicating a greater range of utilization of basal C 3 and C 4 resources in the former site, covering primary productivity from both these sources. The ranges in δ 15 N, however, were similar between the two habitats suggesting a similar number of trophic levels. Niche breadth, as defined by either standard ellipse area or convex hull, was greater for the bat community in rainforest than in savannah, with all four foraging groups having larger niche breadths in the former than the latter. The higher inter-species morphospace and niche breadth in forest bats suggest that species packing is not necessarily competitive. By employing morphometrics and stable isotope analysis, we have shown that the rainforest bat community packs more species in morphospace and uses a larger niche breadth than the one in savannah.

Assessing the diet and trophic niche breadth of an omnivorous fish (Glanidium ribeiroi) in subtropical lotic environments: intraspecific and ontogenic responses to spatial variations

2019 ◽  
Vol 70 (8) ◽  
pp. 1116 ◽  
Author(s):  
B. C. K. Kliemann ◽  
M. C. Baldasso ◽  
S. F. R. Pini ◽  
M. C. Makrakis ◽  
S. Makrakis ◽  
...  
Keyword(s):  
Forest Cover ◽  
Agricultural Land ◽  
Niche Breadth ◽  
Intraspecific Variability ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Main Channel ◽  
Size Classes ◽  
Intraspecific Variations ◽  
Environmental Variations

The diet of Glanidium ribeiroi was investigated in lotic stretches downstream from a cascade of reservoirs to determine how it responds to intraspecific and environmental variations. Monthly sampling was performed from 2013 to 2016 at sites including the main channel of the Iguaçu River and tributaries in preserved basins and agricultural land. The diet of individuals in the preserved tributaries was primarily associated with allochthonous resources, whereas in the non-preserved tributaries and main channel the diets were primarily associated with autochthonous resources. Trophic niche breadth and intraspecific variability differed significantly among sampling areas and size classes. Trophic niche overlap among size classes and sampling areas was low. Positive and negative relationships between the trophic niche breadth and the standard length of individuals were also found in different sampling areas. Intraspecific and ontogenic variations were strongly and consistently associated with forest cover. Individuals responded differently to local environmental variations due to differences in landscape gradients and life cycle changes. Therefore, the effects of spatial heterogeneity on diet composition and intraspecific variations therein appear to be crucial to the success of the populations evaluated. These results may help with the implementation of conservation measures for this and other endemic species.

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