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.

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 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.

scholarly journals Assessing Suitable Habitats for Treefrog Species after Previous Declines in Costa Rica

Diversity ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 577
Author(s):  
Héctor Zumbado-Ulate ◽  
Catherine L. Searle ◽  
Gerardo Chaves ◽  
Víctor Acosta-Chaves ◽  
Alex Shepack ◽  
...  
Keyword(s):  
Costa Rica ◽  
Sympatric Species ◽  
Costa Rican ◽  
Suitable Habitat ◽  
Minimum Convex Polygon ◽  
Amphibian Species ◽  
Environmental Threats ◽  
The Status ◽  
Suitable Habitats ◽  
Iucn Assessment

Treefrogs represent 22% of amphibian species in Costa Rica, but gaps in the knowledge about this group of amphibians can impede conservation efforts. In this study, we first updated the status of Costa Rican treefrogs and found that a total of 38% of treefrog species are threatened according to the most recent IUCN assessment in 2019. Additionally, 21% of Costa Rican treefrog species have a high vulnerability to extinction according to environmental vulnerability scores. Then, we predicted the historical climatic suitability of eight target species that we expected to have exhibited changes in their ranges in the last 20 years. We assessed the location of new occurrence records since 2000 to identify recovery, range expansion, or previously underestimated ranges due to methodological limitations. We also estimated the area of each species’ suitable habitat with two metrics: extent of suitable habitat (ESH) and area of minimum convex polygon (AMCP). Six declined species exhibited recovery (i.e., new occurrences across historical range after 2000), with the widest recovery found in Agalychnis annae. We also found that Isthmohyla pseudopuma appears to have spread after the decline of sympatric species and that the range of I. sukia was originally underestimated due to inadequate detection. We found that the ESH was 32–49% smaller than the AMCP for species that are slowly recovering; however, the ESH is similar or greater than the AMCP for species that are recovering in most of their ranges, as well as rare species with widespread ranges. Results of this work can be used to evaluate the risk of environmental threats and prioritize regions for conservation purposes.

scholarly journals Fungal infection, decline and persistence in the only obligate troglodytic Neotropical salamander

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9763
Author(s):  
Mizraim Olivares-Miranda ◽  
Vance T. Vredenburg ◽  
Julio C. García-Sánchez ◽  
Allison Q. Byrne ◽  
Erica B. Rosenblum ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Infection Intensity ◽  
Sampling Technique ◽  
Sympatric Species ◽  
Amphibian Declines ◽  
Small Range ◽  
Museum Specimens ◽  
Amphibian Species ◽  
Extant Population ◽  
Epidemic Wave

The fungal pathogen Batrachochytrium dendrobatidis (Bd) is implicated in global mass die-offs and declines in amphibians. In Mesoamerica, the Bd epidemic wave hypothesis is supported by detection of Bd in historic museum specimens collected over the last century, yet the timing and impact of the early stages of the wave remain poorly understood. Chiropterotriton magnipes, the only obligate troglodytic Neotropical salamander, was abundant in its small range in the decade following its description in 1965, but subsequently disappeared from known localities and was not seen for 34 years. Its decline is roughly coincident with that of other populations of Neotropical salamanders associated with the invasion and spread of Bd. To determine the presence and infection intensity of Bd on C. magnipes and sympatric amphibian species (which are also Bd hosts), we used a noninvasive sampling technique and qPCR assay to detect Bd on museum specimens of C. magnipes collected from 1952 to 2012, and from extant populations of C. magnipes and sympatric species of amphibians. We also tested for the presence of the recently discovered Batrachochytrium salamandivorans (Bsal), another fungal chytridiomycete pathogen of salamanders, using a similar technique specific for Bsal. We did not detect Bd in populations of C. magnipes before 1969, while Bd was detected at low to moderate prevalence just prior to and during declines. This pattern is consistent with Bd-caused epizootics followed by host declines and extirpations described in other hosts. We did not detect Bsal in any extant population of C. magnipes. We obtained one of the earliest positive records of the fungus to date in Latin America, providing additional historical evidence consistent with the Bd epidemic wave hypothesis. Genotyping results show that at least one population is currently infected with the Global Panzootic Lineage of Bd, but our genotyping of the historical positive samples was unsuccessful. The lack of large samples from some years and the difficulty in genotyping historical Bd samples illustrate some of the difficulties inherent in assigning causality to historical amphibian declines. These data also provide an important historical baseline for actions to preserve the few known remaining populations of C. magnipes.

Mechanisms of heterospecific recognition in avian mobbing calls

2003 ◽  
Vol 51 (6) ◽  
pp. 577 ◽  
Author(s):  
Frances R. Johnson ◽  
Elisabeth J. McNaughton ◽  
Courtney D. Shelley ◽  
Daniel T. Blumstein
Keyword(s):  
Sympatric Species ◽  
Dominant Frequency ◽  
Playback Experiments ◽  
Broad Bandwidth ◽  
Call Recognition ◽  
Allopatric Species ◽  
Interspecific Recognition ◽  
And Function

Some birds emit special calls, referred to as mobbing calls, when they detect a predator in their area. These calls are easily localisable and function to rally other individuals to help chase out a threatening intruder. Interestingly, individuals may respond to the mobbing calls of other sympatric species. To understand the mechanism underlying interspecific recognition it is essential to determine whether birds also respond to the mobbing calls of allopatric species. If, as has been suggested, learning is important for call recognition, then calls from allopatric species should not evoke mobbing. If, however, there are intrinsic (and possibly convergent) characteristics of mobbing calls, then novel calls from allopatric species should evoke mobbing. We conducted two playback experiments with apostlebirds (Struthidea cinera, Family Corcoracidae), Australian mud-nesters, to understand mechanisms underlying mobbing-call recognition. The first demonstrated that allopatric mobbing calls could elicit a response significantly greater than control stimuli, but less than that elicited by playback of conspecific calls. The second demonstrated that the dominant frequency was critical for eliciting mobbing, rather than the commonly assumed broad bandwidth. Taken together, these results suggest that experience with a particular species' call is not essential to elicit mobbing; rather, intrinsic aspects of the calls themselves may explain heterospecific recognition.

scholarly journals Vocal Communication Within a Forest Bird Community

2021 ◽  
Author(s):  
◽  
Joseph Fawzi Azar
Keyword(s):  
Bird Community ◽  
Song Thrush ◽  
Forest Bird ◽  
Acoustic Adaptation ◽  
Acoustic Niche ◽  
Adaptation Hypothesis ◽  
Acoustic Space ◽  
Acoustic Adaptation Hypothesis ◽  
The Uk ◽  
Study Species

<p><b>This thesis takes a community approach to investigate the acoustics of forest birds in Zealandia sanctuary, Wellington. Initially, the annual changes in vocalisation output of 16 study species and their possible effect on bird conspicuousness were described. Environmental factors that may shape these avian vocalisations were addressed though invoking two key hypotheses, the acoustic adaptation hypothesis, and the acoustic niche hypothesis. In addition, the songs of selected species are investigated: the role of song harmonics in the native North Island saddleback, Philesturnus rufusater, and their role in ranging, change in song dialect through time and space in the introduced song thrush, Turdus philomelos, and temporal change in the song of the native grey warbler, Greygone igata. Vocal activity of the study species varied seasonally, affecting their detectability in bird counts. Some species were mostly first heard rather than seen and viceversa. The results lend support to the acoustic niche hypothesis in that vocalisations within the forest bird community appear to have evolved towards divergence, with native species’ vocalisations being more dispersed within the community acoustic space than those of the introduced species. However, all species concentrated their energy within relatively narrow frequency bands, supporting the predictions of the acoustic adaptation hypothesis. Adaptation to different transmission properties associated with different singing elevations or physiological parameters such as body weight may have an effect on shaping such bird vocalisations.</b></p> <p>Forests provide a complex acoustic space for sound transmission and a “sound window” may not be a constant property of a given forest. The study revealed that a prominent sound window persists in the lower frequency range that is less affected by habitat. Some high frequencies may have similar average attenuation values to those of low frequency, however, with greater fluctuation in attenuation. Ground effect is a further factor in determining how well different frequency ranges transmit and birds may use acoustic characteristics of their habitat to enhance their signal.</p> <p>Harmonics in North Island saddleback chatter song were found to play a potential role in ranging (estimating the distance of signaller), for playback songs with more relative energy within higher harmonics were evidently perceived as coming from a nearby individual.</p> <p>The repertoire size of the song thrush population studied in Zealandia has apparently evolved to become larger and more varied than the source population of song thrushes in the UK, with more syllables delivered with less repetition than the UK song recordings examined.</p> <p>Over a period of 7 years, syllables in grey warbler song have shifted to a higher frequency, but there was no difference in the temporal structure of the song. Habitat effect, competition on the acoustic signal from reintroduced birds and ambient noise level are considered as possible casual factors.</p>

scholarly journals Feature Based Face Recognition using Machine Learning Technniques

2020 ◽  
Vol 8 (6) ◽  
pp. 1313-1317
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Face Recognition ◽  
Euclidean Distance ◽  
Human Face ◽  
Cosine Transformation ◽  
The Face ◽  
Feature Based ◽  
Haar Cascade ◽  
Distinct Features

Human Face has Numerous unique Features to Distinguish between each other. Face can Identified by distinguishing between face and non-face followed by Identification. Traditionally face recognition uses distinct features Comparison to Identify the Faces which is Complex for larger databases and ambiguous in many scenarios. To improve the accuracy and Scalability Proposed method uses machine learning based Haar Cascade technique for face detection and convolutional neural network is used for feature extraction followed by classification using Euclidean distance and cosine transformation to recognize the face. The results demonstrate the work is performed well in recognizing the face efficiently with different variations.

Acoustic niche partitioning in an anuran community inhabiting an Afromontane wetland (Butare, Rwanda)

2012 ◽  
Vol 47 (1) ◽  
pp. 60-73 ◽  
Author(s):  
Ulrich Sinsch ◽  
Katrin Lümkemann ◽  
Katharina Rosar ◽  
Christiane Schwarz ◽  
Maximilian Dehling
Keyword(s):  
Niche Partitioning ◽  
Acoustic Niche

scholarly journals On the brink of extinction: two new species of Anomaloglossus from French Guiana and amended definitions of Anomaloglossus degranvillei and A. surinamensis (Anura: Aromobatidae)

Zootaxa ◽  
2018 ◽  
Vol 4379 (1) ◽  
pp. 1 ◽  
Author(s):  
FOUQUET ANTOINE ◽  
JEAN-PIERRE VACHER ◽  
ELODIE A. COURTOIS ◽  
BENOIT VILLETTE ◽  
HUGO REIZINE ◽  
...  
Keyword(s):  
New Species ◽  
Body Size ◽  
French Guiana ◽  
Small Body ◽  
Morphological Characters ◽  
Dominant Frequency ◽  
Species Group ◽  
Amphibian Species ◽  
North Eastern ◽  
Group A

A large portion of the amphibian species occurring in Amazonia remains undescribed. A recent study on species delineation in Anomaloglossus, a genus endemic to the Guiana Shield, demonstrated the existence of two undescribed species previously identified as A. degranvillei, which we describe herein. In addition to divergence at the molecular level, these two new taxa are also distinguished by subtle morphological characters and substantial differences in the advertisement calls (note length, dominant frequency, note structure). One species occurs in the hilly lowlands of north-eastern French Guiana and is mainly distinguished from its closest relatives by a small body size (15.9–18.8 mm in males) and by vocalisations characterized by the emission of short notes of 0.09 s on average. The other species is only known from the Itoupé Massif in southern French Guiana and is mainly distinguished from its closest relatives by a moderate body size (19.4–20.4 mm in males) and by vocalisations characterized by the emission of long notes of 0.23 s on average. We also provide amended definitions for two previously described species in the A. degranvillei species group: A. degranvillei, which is endemic to a few massifs in central French Guiana, and A. surinamensis, which is distributed throughout Suriname and French Guiana. The new species described here and A. degranvillei have very narrow ranges within French Guiana and seem to have rapidly declined during the last decade. Therefore, we suggest A. degranvillei and A. dewynteri to be considered as “Critically Endangered” and A. blanci as “Vulnerable” according to the IUCN standards. 

Locomotor correlates of ecomorph designation in Anolis: an examination of three sympatric species from Jamaica

1992 ◽  
Vol 70 (4) ◽  
pp. 725-739 ◽  
Author(s):  
G. Lawrence Powell ◽  
Anthony P. Russell
Keyword(s):  
Body Size ◽  
Niche Partitioning ◽  
Sympatric Species ◽  
Limb Length ◽  
Greater Antilles ◽  
Adult Size ◽  
Allometric Models ◽  
Use Patterns ◽  
Interspecific Differences

Scaling of locomotor structures (limb length, scansor area, and intergirdle distance) in three Jamaican Anolis species (A. garmani, A. grahami, and A. opalinus) is examined. Reference to structural-niche use patterns and partitionings typical of these three species is made. Each species represents a separate Anolis ecomorph, differing from the others in adult size, shape, and structural niche. All are part of a single intra-island phyletic radiation. Allometric models indicate that intra- and inter-specific differences in proportion of locomotor structures are not necessarily ontogenetically invariant, but that all three species ontogenetically arrive at, or have attained, the differences in proportion typical of their adult sizes. Differences in adult proportion between two species are not functions of body size alone but are the products of different scaling trajectories. No intraspecific differences in structural-niche use are documented, but interspecific differences are well defined: the greater the number of differences in locomotor scaling between two species, the greater the structural-niche partitioning. We suggest that the locomotor structure scaling patterns observed in these three species are typical of the ecomorphs that they represent. Analogous ontogenetic patterns of development should be displayed by independently derived representatives of these ecomorphs from other Greater Antilles islands.

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