Advances in the study of the trophic niche of batoids with distribution in Mexican waters

Abstract Habitat complexity is recognized to mediate predator–prey relationships by offering refuge or not. We investigated the availability of planktonic microcrustaceans and the diet of a planktivorous fish (Hyphessobrycon eques) at different levels (low, intermediate and high) of aquatic macrophyte biomass. Sampling was carried out in a river with low flow speed, located in a Neotropical floodplain. We collected fish and microcrustaceans in macrophyte stands with variations in biomass. There were no differences in microcrustacean density in the water among the levels of macrophyte biomass, but microcrustacean richness and diet composition of H. eques differed. Microcrustacean richness and trophic niche breadth of the planktivorous fish were higher in high biomass stands. There was high consumption of a small cladoceran species in low macrophyte biomass, which was replaced by larger species, such as copepods, in intermediate and high biomass. Thus, the selection of some species was different among the biomass levels. These results suggest that plant biomass plays an important role in the interaction between fish and microcrustaceans, and prey characteristics such as size, escape ability and energy value make them more or less subject to predation by fish according to habitat structuring.

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Multidimensional trophic niche revealed by complementary approaches: gut content, digestive enzymes, fatty acids and stable isotopes in Collembola

Journal of Animal Ecology ◽

10.1111/1365-2656.13511 ◽

2021 ◽

Author(s):

Anton M. Potapov ◽

Melanie M. Pollierer ◽

Sandrine Salmon ◽

Vladimír Šustr ◽

Ting‐Wen Chen

Keyword(s):

Fatty Acids ◽

Stable Isotopes ◽

Digestive Enzymes ◽

Trophic Niche ◽

Gut Content

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Low individual diet variation and high trophic niche overlap between the native polecat and invasive American mink

Journal of Zoology ◽

10.1111/jzo.12871 ◽

2021 ◽

Author(s):

A. Zalewski ◽

M. Szymura ◽

R. Kowalczyk ◽

M. Brzeziński

Keyword(s):

American Mink ◽

Niche Overlap ◽

Trophic Niche ◽

Diet Variation

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The food web in a subterranean ecosystem is driven by intraguild predation

Scientific Reports ◽

10.1038/s41598-021-84521-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Andrea Parimuchová ◽

Lenka Petráková Dušátková ◽

Ľubomír Kováč ◽

Táňa Macháčková ◽

Ondřej Slabý ◽

...

Keyword(s):

Food Web ◽

Trophic Interactions ◽

Intraguild Predation ◽

Linear Models ◽

Niche Overlap ◽

Trophic Niche ◽

High Availability ◽

Large Prey ◽

Arthropod Predators ◽

Body Sizes

AbstractTrophic interactions of cave arthropods have been understudied. We used molecular methods (NGS) to decipher the food web in the subterranean ecosystem of the Ardovská Cave (Western Carpathians, Slovakia). We collected five arthropod predators of the species Parasitus loricatus (gamasid mites), Eukoenenia spelaea (palpigrades), Quedius mesomelinus (beetles), and Porrhomma profundum and Centromerus cavernarum (both spiders) and prey belonging to several orders. Various arthropod orders were exploited as prey, and trophic interactions differed among the predators. Linear models were used to compare absolute and relative prey body sizes among the predators. Quedius exploited relatively small prey, while Eukoenenia and Parasitus fed on relatively large prey. Exploitation of eggs or cadavers is discussed. In contrast to previous studies, Eukoenenia was found to be carnivorous. A high proportion of intraguild predation was found in all predators. Intraspecific consumption (most likely cannibalism) was detected only in mites and beetles. Using Pianka’s index, the highest trophic niche overlaps were found between Porrhomma and Parasitus and between Centromerus and Eukoenenia, while the lowest niche overlap was found between Parasitus and Quedius. Contrary to what we expected, the high availability of Diptera and Isopoda as a potential prey in the studied system was not corroborated. Our work demonstrates that intraguild diet plays an important role in predators occupying subterranean ecosystems.

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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 ◽

10.3390/w13020195 ◽

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.

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Three-dimensional niche partitioning between two colonially nesting ardeid species in central China

Avian Research ◽

10.1186/s40657-021-00264-7 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yuanxing Ye ◽

Canshi Hu ◽

Yiting Jiang ◽

Geoffrey W. H. Davison ◽

Changqing Ding

Keyword(s):

Niche Partitioning ◽

Trophic Niche ◽

Egg Laying ◽

Central China ◽

Paddy Fields ◽

Shaanxi Province ◽

Similar Species ◽

Wetland Birds ◽

Cattle Egret ◽

River Banks

Abstract Background Interspecific competition is known to be strongest between those species that are both closely related and sympatric. Egrets are colonially nesting wetland birds that often overlap and can therefore be expected to compete in roosting and nesting habitat as well as in diet. According to the niche partitioning hypothesis, it is to be expected that these similar species would show differentiation in at least one of the main niche dimensions to reduce competition. We tested niche partitioning between the colonially nesting Little Egret (Egretta garzetta) and Cattle Egret (Bubulcus ibis) in temporal, spatial and trophic dimensions. Methods Field study was conducted in three mixed egret colonies in Yangxian County, southwest Shaanxi Province, central China. For each nest colony we recorded its spatial location, the height of nesting trees and of nests, the height of roosting trees and of roosting individuals within the trees. We determined the first egg-laying and first hatching dates of the two species. Craw dissection of storm-killed egret nestlings was used to measure the diet. Six transects were surveyed to study foraging habitat selection. Results We found that hatching time of Little Egrets peaked earlier (by about 1 month) than that of Cattle Egrets. Cattle Egrets nested and roosted higher than Little Egrets. The foraging habitats used by Little Egrets were dominated by river banks (73.49%), followed by paddy fields (13.25%) and reservoirs (10.84%), whereas Cattle Egret foraging sites were characterized by grasslands (44.44%), paddy fields (33.33%) and river banks (22.22%). Little Egrets consumed more fishes (65.66%) and Odonata larvae (13.69%) than Cattle Egrets, while Cattle Egrets were found feeding mainly on Coleoptera (29.69%) and Orthoptera (23.29%). Little Egrets preyed on larger mean biomasses of food items than Cattle Egrets. Conclusions Our results confirm the niche partitioning hypothesis as a mechanism for coexistence among ecologically similar species. In two coexisting egret species, niche partitioning is multidimensional, such that the two coexistent species occupy differing ecological space based on all three temporal, spatial and trophic niche dimensions.

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