Acoustic niche partitioning in five Cuban frogs of the genus Eleutherodactylus

2019 ◽  
Vol 40 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Irelis Bignotte-Giró ◽  
Ansel Fong G. ◽  
Germán M. López-Iborra
Keyword(s):  
Species Coexistence ◽  
Niche Partitioning ◽  
Sympatric Species ◽  
Egg Laying ◽  
Signal Frequency ◽  
Time Signal ◽  
Time Frequency ◽  
Sound Communication ◽  
Acoustic Niche ◽  
Single Genus

Abstract Acoustic segregation is a way to reduce competition and allows for species coexistence within anuran communities. Thus, separation in at least one acoustic niche dimension is expected, which also contributes to achieving effective communication among frogs. Here we studied an assemblage of five terrestrial egg-laying anuran species, all in the genus Eleutherodactylus, in a montane rainforest in eastern Cuba. Our aim was to determine if partitioning exists between these species in any dimension (time, signal frequency or space) of the acoustic niche. The studied assemblage had the following characteristics: (1) there was one diurnal species, two species with calling activity throughout the day and two species that call at night; (2) only two species overlapped in call frequencies and most had different calls, both in terms of dominant frequencies and in temporal characteristics; and (3) males of the species that overlapped in vocalizing time or signal frequency used different calling microhabitats or heights. This study provides evidence for the acoustic niche hypothesis in anurans, showing low probabilities of interference in sound communication among these frogs. The five species were separated in at least one of the three acoustic dimensions (calling time, frequency and site) as it occurs in mainland communities with more sympatric species of several genera. Conversely, species in single-genus communities studied in Puerto Rico overlapped completely in calling times. This seems to be due to the higher number of sympatric species at our site.

scholarly journals Acoustic niche partitioning in an anuran community from the municipality of Floriano, Piauí, Brazil

2019 ◽  
Vol 79 (4) ◽  
pp. 566-576 ◽  
Author(s):  
M. S. C. S. Lima ◽  
J. Pederassi ◽  
R. B. Pineschi ◽  
D. B. S. Barbosa
Keyword(s):  
Euclidean Distance ◽  
Niche Partitioning ◽  
Sympatric Species ◽  
Dominant Frequency ◽  
Amphibian Species ◽  
Acoustic Interference ◽  
Acoustic Niche ◽  
Important Trait ◽  
Acoustic Space ◽  
Distinct Features

Abstract Vocalizations are an important trait for the identification of cryptic and/or closely related amphibian species. Different vocalizations also contribute to partitioning of the acoustic space by sympatric species. This study aimed to describe the advertisement calls of anurans in a pond of the municipality of Floriano, State of Piauí, Brazil, and infer the acoustic niche partitioning of amphibians. Euclidean distance was used in a cluster analysis approach to infer the acoustic similarities among species. Thirteen species were analysed: Boana raniceps, Dendropsophus nanus, D. rubicundulus , D. minutus, Leptodactylus fuscus, L. troglodytes, L. vastus, Pithecopus nordestinus , Physalaemus cuvieri, P. nattereri, Pleurodema diplolister, Proceratophrys cristiceps and Scinax ruber. From these, six showed more than 90% of acoustic overlap: P. nattereri , P. cuvieri, L. fuscus and L. vastus (Leptodactylidae); and, D. nanus and D. rubicundulus (Hylidae). Despite the acoustic similarities among these six species, the acoustic interference was reduced due to the small number of sympatric species and to distinct features on carrier frequency such as dominant frequency and the degree of modulation in the frequency. Environmental factors limit the periods and sites of reproduction respectively, which may maintain the low anuran diversity and consequently reduce acoustic overlap.

scholarly journals Niche partitioning and the role of intraspecific niche variation in structuring a guild of generalist anurans

2017 ◽  
Vol 4 (3) ◽  
pp. 170060 ◽  
Author(s):  
Carl S. Cloyed ◽  
Perri K. Eason
Keyword(s):  
Carbon Isotope ◽  
Intraspecific Variation ◽  
Trophic Level ◽  
Species Coexistence ◽  
Niche Partitioning ◽  
Stomach Contents ◽  
Sympatric Species ◽  
Trophic Levels ◽  
Niche Differences ◽  
Niche Variation

Intra-population niche differences in generalist foragers have captured the interest of ecologists, because such individuality can have important ecological and evolutionary implications. Few researchers have investigated how these differences affect the relationships among ecologically similar, sympatric species. Using stable isotopes, stomach contents, morphology and habitat preference, we examined niche partitioning within a group of five anurans and determined whether variation within species could facilitate resource partitioning. Species partitioned their niches by trophic level and by foraging habitat. However, there was considerable intraspecific variation in trophic level, with larger individuals generally feeding at higher trophic levels. For species at intermediate trophic levels, smaller individuals overlapped in trophic level with individuals of smaller species and larger individuals overlapped with the smallest individuals from larger species. Species varied in carbon isotopes; species with enriched carbon isotope ratios foraged farther from ponds, whereas species with depleted carbon isotope values foraged closer to ponds. Our study shows that these species partition their niches by feeding at different trophic levels and foraging at different distances from ponds. The intraspecific variation in trophic level decreased the number of individuals from each species that overlapped in trophic level with individuals from other species, which can facilitate species coexistence.

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

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.

scholarly journals Foraging niche partitioning in sympatric seabird populations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christina Petalas ◽  
Thomas Lazarus ◽  
Raphael A. Lavoie ◽  
Kyle H. Elliott ◽  
Mélanie F. Guigueno
Keyword(s):  
Interspecific Competition ◽  
Niche Partitioning ◽  
Niche Differentiation ◽  
Sympatric Species ◽  
Foraging Strategies ◽  
Gps Tracking ◽  
Seabird Species ◽  
Foraging Range ◽  
Common Murre ◽  
Prey Items

AbstractSympatric species must sufficiently differentiate aspects of their ecological niche to alleviate complete interspecific competition and stably coexist within the same area. Seabirds provide a unique opportunity to understand patterns of niche segregation among coexisting species because they form large multi-species colonies of breeding aggregations with seemingly overlapping diets and foraging areas. Recent biologging tools have revealed that colonial seabirds can differentiate components of their foraging strategies. Specifically, small, diving birds with high wing-loading may have small foraging radii compared with larger or non-diving birds. In the Gulf of St-Lawrence in Canada, we investigated whether and how niche differentiation occurs in four incubating seabird species breeding sympatrically using GPS-tracking and direct field observations of prey items carried by adults to chicks: the Atlantic puffin (Fratercula arctica), razorbill (Alca torda), common murre (Uria aalge), and black-legged kittiwake (Rissa tridactyla). Although there was overlap at foraging hotspots, all species differentiated in either diet (prey species, size and number) or foraging range. Whereas puffins and razorbills consumed multiple smaller prey items that were readily available closer to the colony, murres selected larger more diverse prey that were accessible due to their deeper diving capability. Kittiwakes compensated for their surface foraging by having a large foraging range, including foraging largely at a specific distant hotspot. These foraging habitat specialisations may alleviate high interspecific competition allowing for their coexistence, providing insight on multispecies colonial living.

A New Method for Phase Difference Estimation Based on Time-Varying Signal Model

2013 ◽  
Vol 333-335 ◽  
pp. 650-655
Author(s):  
Peng Hui Niu ◽  
Yin Lei Qin ◽  
Shun Ping Qu ◽  
Yang Lou
Keyword(s):  
Signal Processing ◽  
Real Time ◽  
Phase Difference ◽  
Time Signal ◽  
Time Interval ◽  
Time Varying ◽  
Signal Model ◽  
Time Frequency ◽  
Mass Flowmeter ◽  
Coriolis Mass Flowmeter

A new signal processing method for phase difference estimation was proposed based on time-varying signal model, whose frequency, amplitude and phase are time-varying. And then be applied Coriolis mass flowmeter signal. First, a bandpass filtering FIR filter was applied to filter the sensor output signal in order to improve SNR. Then, the signal frequency could be calculated based on short-time frequency estimation. Finally, by short window intercepting, the DTFT algorithm with negative frequency contribution was introduced to calculate the real-time phase difference between two enhanced signals. With the frequency and the phase difference obtained, the time interval of two signals was calculated. Simulation results show that the algorithms studied are efficient. Furthermore, the computation of algorithms studied is simple so that it can be applied to real-time signal processing for Coriolis mass flowmeter.

scholarly journals Classification of Emotional States Inparkinson’s Disease Patients Using Time,Frequency and Time-Frequency Analysis

2021 ◽  
Author(s):  
Rejith K.N ◽  
Kamalraj Subramaniam ◽  
Ayyem Pillai Vasudevan Pillai ◽  
Roshini T V ◽  
Renjith V. Ravi ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Classification Accuracy ◽  
Machine Learning Algorithms ◽  
Signal Frequency ◽  
Spectral Energy ◽  
Support Vector ◽  
Svm Classifier ◽  
Time Frequency ◽  
Energy Entropy ◽  
Teager Energy

Abstract In this work, PD patients and healthy individuals were categorized with machine-learning algorithms. EEG signals associated with six different emotions, (Happiness(E1), Sadness(E2), Fear(E3), Anger(E4), Surprise,(E5) and disgust(E6)) were used for the study. EEG data were collected from 20 PD patients and 20 normal controls using multimodal stimuli. Different features were used to categorize emotional data. Emotional recognition in Parkinson’s disease (PD) has been investigated in three domains namely, time, frequency and time frequency using Entropy, Energy-Entropy and Teager Energy-Entropy features. Three classifiers namely, K-Nearest Neighbor Algorithm, Support Vector Machine and Probabilistic Neural Network were used to observethe classification results. Emotional EEG stimuli such as anger, surprise, happiness, sadness, fear, and disgust were used to categorize PD patients and healthy controls (HC). For each EEG signal, frequency features corresponding to alpha, beta and gamma bands were obtained for nine feature extraction methods (Entropy, Energy Entropy, Teager Energy Entropy, Spectral Entropy, Spectral Energy-Entropy, Spectral Teager Energy-Entropy, STFT Entropy, STFT Energy-Entropy and STFT Teager Energy-Entropy). From the analysis, it is observed that the entropy feature in frequency domain performs evenly well (above 80 %) for all six emotions with KNN. Classification results shows that using the selected energy entropy combination feature in frequency domain provides highest accuracy for all emotions except E1 and E2 for KNN and SVM classifier, whereas other features give accuracy values of above 60% for most emotions.It is also observed that emotion E1 gives above 90 % classification accuracy for all classifiers in time domain.In frequency domain also, emotion E1 gives above 90% classification accuracy using PNN classifier.

Reproductive biology of two sympatric colubrid snakes, Chironius flavolineatus and Chironius quadricarinatus, from the Brazilian Cerrado domain

2010 ◽  
Vol 31 (4) ◽  
pp. 463-473 ◽  
Author(s):  
Roberta Richard Pinto ◽  
Otavio Augusto Vuolo Marques ◽  
Ronaldo Fernandes
Keyword(s):  
Reproductive Biology ◽  
Sexual Maturity ◽  
Egg Production ◽  
Sympatric Species ◽  
Egg Laying ◽  
Reproductive Pattern ◽  
Brazilian Cerrado ◽  
Wet Season ◽  
Reproductive Cycles ◽  
First Time

AbstractThe reproductive biology of Chironius flavolineatus and C. quadricarinatus from the Brazilian Cerrado domain is described, including sexual maturity, female fecundity, and reproductive cycles of males and females. Egg-laying is recorded here for the first time for C. quadricarinatus. Males of both species attain sexual maturity with a smaller snout-vent length than females. Females of C. flavolineatus have an extended reproductive cycle with egg production during the wet season, whereas males exhibit year-round sperm production. Chironius quadricarinatus has continuous reproductive cycles in both sexes. Differences in reproductive pattern between these two sympatric species are probably related to phylogenetic constraints on intrageneric lineages of Chironius.

Fault Diagnosis of Rolling Bearing Based on S Transform and Image of Invariant Moments

2013 ◽  
Vol 706-708 ◽  
pp. 798-802 ◽  
Author(s):  
Jun Feng Guo ◽  
Bao Zeng Wang ◽  
Peng Wei ◽  
Xing Chun Wei
Keyword(s):  
Fault Diagnosis ◽  
Rolling Bearing ◽  
Frequency Function ◽  
Time Signal ◽  
Two Dimensional ◽  
Moment Invariant ◽  
Time Frequency ◽  
Bearing Fault ◽  
Two Dimensional Image ◽  
Invariant Moments

According the characteristics of rolling bearing fault information are nonlinear and non-stationary, the method of time-frequency is often used to make the one dimensional time signal map into two dimensional time and frequency function, and describe the energy density of signal at different times and frequency simultaneously. A method of fault diagnosis based on S transformation and image Hu of invariant moments was put forward in this paper. First of all the measured rolling bearing signals have been S transformed, and time-frequency spectrum which is got is expressed as two dimensional image, then Hu geometric moment invariant of the S transformation spectrum is calculated and the simulation research is carried out using invariant moment principle in image processing. The results show that this method can distinguish the inner ring, outer ring and bearing roller fault intuitively and accurately and measure rolling bearing fault diagnosis efficiently.

An Improved Random Decrement Algorithm and Applications

2011 ◽  
Vol 121-126 ◽  
pp. 4372-4376
Author(s):  
Qing Wei Ye ◽  
Zhi Min Feng ◽  
Hai Gang Hu
Keyword(s):  
Response Function ◽  
Vibration Signal ◽  
Recognition Algorithm ◽  
Mode Analysis ◽  
Time Signal ◽  
Signal Acquisition ◽  
Free Response ◽  
Time Frequency ◽  
Random Decrement Technique ◽  
Random Decrement

The free response function is the foundation of mode analysis and recognition of vibration signal, and random decrement algorithm is the commonly used classical algorithm of extracting the free response function. But under the restriction of engineering conditions, it may be impossible for long-time signal acquisition, which makes the number of sample points fail to meet the requirements of the random decrement algorithm, causing the extracted free response signals to contain strong noise and other influencing factors. Aiming at the shortcomings of the existing random decrement technique, this paper proposes an improved random decrement algorithm based on multi-secant method, which can get satisfactory free response signals with short vibration response signals to provide excellent basis of analysis for the vibration mode recognition algorithm of various time-frequency domains. Actual engineering tests confirm that the improved algorithm greatly improves the precision of extracting free response signals while basically keeping the computation speed unchanged, it has high application value.

scholarly journals Species coexistence and overlapping distributions in a metacommunity are compatible with niche differences and competition at a local scale

2020 ◽  
Author(s):  
Maxime Dubart ◽  
Patrice David ◽  
Frida Ben-Ami ◽  
Christoph R. Haag ◽  
V. Ilmari Pajunen ◽  
...  
Keyword(s):  
Species Coexistence ◽  
Scale Up ◽  
Niche Partitioning ◽  
Niche Differentiation ◽  
Apparent Paradox ◽  
Extinction Rates ◽  
Interspecific Differences ◽  
Baltic Coast ◽  
Species Specific

AbstractNiche partitioning is the most studied factor structuring communities of competing species. In fragmented landscapes, however, a paradox can exist: different taxa may competitively dominate different types of habitat patches, resulting in a form of spatial niche partitioning, yet differences in long-term distributions among species can appear surprisingly small. This paradox is illustrated by an emblematic metacommunity - that of Daphnia spp. in rockpools on the Finnish Baltic coast, where three species compete with each other, have distinct ecological preferences, yet largely overlap in long-term distributions. Here we examine how metacommunity models that explicitly estimate species-specific demographic parameters can solve the apparent paradox. Our research confirms previous studies that local extinction rates are influenced by environmental variables in a strong and species-specific way and are considerably increased by interspecific competition. Yet, our simulations show that this situation exists alongside interspecific differences in realized niches that are, overall, small, and identified three main explanations for this compatibility. Our results illustrate how state-space modelling can clarify complex metacommunity dynamics and explain why local competition and niche differentiation do not always scale up to the landscape level.

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