Analysing patterns of spatial and niche overlap among species at multiple resolutions

The current work investigates dietary overlap and food partitioning among nine abundant carnivorous fishes caught in the shallow waters of the Paraíba do Norte river estuary, Paraíba State, Brazil. Fishes were sampled with a beach seine net between January and December 2008 and a total of 958 specimens had their stomach content analyzed. Crustacea was the dominant food resource for Lutjanus alexandrei, L. jocu and Bathygobius soporator, whereas Telostei were consumed mainly by Centropomus undecimalis and C. parallelus. In contrast, Polychaeta were preyed upon mainly by Diapterus rhombeus, Eucinostomus argenteus, Sciades herzbergii and S. parkeri. Although most species consumed similar food items, they did that in varying proportions and amounts. Overall, the niche overlap among species was low (< 0.60), but there were several cases where pair of species had their feeding niche highly overlapped (between 0.72 and 0.97). These findings corroborate the hypothesis that food resource partitioning determines species coexistence in estuarine tropical environments.

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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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Testing for equality of distributions using the concept of (niche) overlap

Statistical Papers ◽

10.1007/s00362-021-01239-y ◽

2021 ◽

Author(s):

Judith H. Parkinson-Schwarz ◽

Arne C. Bathke

Keyword(s):

Basic Assumption ◽

Type I Error ◽

Test Procedure ◽

Niche Overlap ◽

Relative Effect ◽

Type I ◽

Underlying Distribution ◽

Parametric Test ◽

Higher Power ◽

Non Parametric

AbstractIn this paper, we propose a new non-parametric test for equality of distributions. The test is based on the recently introduced measure of (niche) overlap and its rank-based estimator. As the estimator makes only one basic assumption on the underlying distribution, namely continuity, the test is universal applicable in contrast to many tests that are restricted to only specific scenarios. By construction, the new test is capable of detecting differences in location and scale. It thus complements the large class of rank-based tests that are constructed based on the non-parametric relative effect. In simulations this new test procedure obtained higher power and lower type I error compared to two common tests in several settings. The new procedure shows overall good performance. Together with its simplicity, this test can be used broadly.

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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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Indian Grey Wolf and Striped Hyaena sharing from the same bowl: High niche overlap between top predators in a human-dominated landscape

Global Ecology and Conservation ◽

10.1016/j.gecco.2021.e01682 ◽

2021 ◽

pp. e01682

Author(s):

Tanoy Mukherjee ◽

Ishita Chongder ◽

Shankhamala Ghosh ◽

Akash dutta ◽

Abhishek Singh ◽

...

Keyword(s):

Niche Overlap ◽

Grey Wolf ◽

Top Predators

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Is Over the Top Video Platform the Game Changer over Traditional TV Channels in India? A Niche Analysis

Asia Pacific Media Educator ◽

10.1177/1326365x211009639 ◽

2021 ◽

pp. 1326365X2110096

Author(s):

Hashim Hamza Puthiyakath ◽

Manash Pratim Goswami

Keyword(s):

Video Streaming ◽

Consumer Satisfaction ◽

Niche Overlap ◽

Niche Theory ◽

Substantial Impact ◽

Degree Of Satisfaction ◽

Over The Top ◽

Game Changer

Since the outbreak of COVID-19 and the consequent national lockdown, the usage of over the top (OTT) platforms has significantly increased in India. The growing popularity of video streaming has made a substantial impact on the traditional TV channels during pandemic times. The purpose of this study is to examine the competition, coexistence and competitive superiority of OTT and TV in providing consumer satisfaction. The study adopted the niche theory to empirically measure the degree of gratification fulfilled by OTT and TV, the similarity between OTT and TV and the competitive superiority of OTT and TV across seven micro-dimensions of gratification. The data for the study has been gathered from 223 online users across India. The results of the study reflect that OTT provides a higher degree of satisfaction across all seven dimensions of gratification with the greatest difference manifested in the convenience dimension. The niche overlap measures indicated that the highest level of similarity between TV and OTT is in providing gratification in the relaxation dimension, whereas the least similarity was observed in the convenience dimensions. The competitive superiority of OTT surpassed TV in all dimensions with the greatest difference manifested in relaxation.

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