Niche overlap and resource partitioning among five sympatric bufonids (Anura, Bufonidae) from northeastern Argentina
01 Jun 2009-Phyllomedusa: Journal of Herpetology (Melopsittacus Publicações Científicas)-Vol. 8, Iss: 1, pp 27-39
TL;DR: Studying the diet behaviors and trophic parameters of sympatric species provides important data for understanding the community and for the development of conservation guidelines.
Abstract: Niche overlap and resource partitioning among five sympatric bufonids (Anura, Bufonidae) from northeastern Argentina. The niche overlap and resource partitioning were analyzed for five sympatric bufonids from Northeastern Argenti- na: Rhinella schneideri, R. bergi, R. fernandezae, R. granulosa, and Melanophryniscus cupreuscapularis. The primary objectives were to analyze the diet and pattern of coexistence relative to the microhabitats among species. The bufonids, which are primarily terrestrial, exhibited a preference for small, hard prey such as formicids or coleopterans. The smallest species preferably consumed ants, while R. schneideri preferred beetles. Significant differences were detected for the diets of these five species. In addition, significant overlap in the trophic niche was noted for all species except between R. granulosa and R. schneideri. Studying the diet behaviors and trophic parameters of sympatric species provides important data for understanding the community and for the development of conservation guidelines.
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TL;DR: Both toad species targeted specific food items rather than opportunistically consume prey as observed in most anurans which may be a response to high anuran diversity typically found in the tropics or an adjustment to urban habitats.
Abstract: Suitable habitats for anurans can be found in the ever-growing tropical urban environments but anurans' adaptations to urban conditions, including their trophic ecology remain largely unknown. We studied the food habits of two generalist, widespread West African Sclerophrys adult toads: African common (Sclerophrys regularis) and Hallowell's toad (Sclerophrys maculata). The first was studied in Lome (Togo), Cotonou (Benin) and Ikeja (Nigeria), and the second in Port Harcourt and Ikeja (both Nigeria); the latter city represents the only studied sympatric occurrence. Mean dietary overlap between population pairs was relatively high, and diet composition of the two species when sympatric did not differ significantly. Food niche width was significantly positively correlated with local rainfall in both species, and diet composition changed significantly between the dry and wet seasons. Diversity metrics revealed that females had a more diversified diet, with higher evenness and lower dominance index values than males. The diet of both species was not correlated to prey type availability, in both the wet and dry season. Both toad species targeted specific food items rather than opportunistically consume prey as observed in most anurans which may be a response to high anuran diversity typically found in the tropics or an adjustment to urban habitats.
01 Jan 2015
TL;DR: The vocal repertoire of Melanophryniscus cupreuscapularis, a bufonid toad of the Melanophilea stelzneri species group, which has been recently listed as ''Vulnerable'' by the Asociaci on Herpetol ´ ogica Argentina, is described.
Abstract: We describe the vocal repertoire of Melanophryniscus cupreuscapularis, a bufonid toad of the Melanophryniscus stelzneri species group, which has been recently listed as ''Vulnerable'' by the Asociaci ´ on Herpetol ´ ogica Argentina. Recordings were obtained in ''Paraje El Perich ´ on,'' a relict of Schinopsis balansae ''quebracho'' forest near Corrientes City, Argentina, in September 2007. We provide data on the structure and frequency of three kinds of vocalization: the advertisement, the encounter, and the release calls. We found that the advertisement call is formed by two distinct sections: a first segment consisting of short emissions, usually grouped, and a fast trill. We found that the encounter call is also composed of two segments but that the number of simple emissions in the first segment is greater and more variable (6-60) than in the advertisement call, and the emissions are ungrouped. Although the dominant frequency was similar to the advertisement call, the encounter call frequency was 2,184 Hz (range: 1,832-2,482). The release call is composed of isolated emissions emitted at a lower frequency (1,798 Hz, range: 1,712-1,926) than are the other calls. The structure of the advertisement call was similar to that of other species of the stelzneri group.
DOI•
30 Apr 2021
TL;DR: Adenomera et al. as mentioned in this paper proposed a program for Pós-graduação em ecologia e conservação, which is based on the Coleção Zoologica of the Universidade Federal de Mato Grosso do Sul.
Abstract: 1 Mapinguari, Laboratório de Sistemática e Biogeografia de Anfíbios e Répteis, Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Cidade Universitária, 79002-970 Campo Grande, MS, Brazil. 2 Programa de Pós-graduação em Ecologia e Conservação, Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Cidade Universitária, 79002-970 Campo Grande, MS, Brazil 3 Coleção Zoologica, Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Cidade Universitária, 79002-970 Campo Grande, MS, Brazil. *Corresponding author: adenomera@gmail.com DOI: 10.5281/zenodo.4716416
01 Jan 2014
TL;DR: The results show that B melanostictus has the highest food composition compared to B. asper, and most insects eaten by frogs are ordo of Hymenoptera of the family Formicidae.
Abstract: An abiotic factor is one of the different factors in the composition of food, including frogs. The purpose of this research was to determine the composition of the diet or the food and habitat Two Toads Species Bufo (Phrynoides) asper and Bufo (Duttaphrynus) melanostictus in the Highlands and Lowlands of West Sumatra. The sampling used direct collecting method on the site (Ruler and Iskandar, 2003) and research method refers to methods of Sole et.al. (2005) by analyzing the stomach contents of frogs and counting the number and type of animals eaten. Results of the analysis describes the comparison of animals eaten by frog based on the type and location of the research. The results show that the composition of the highest food contained in the stomach B. melanostictus derived from Plateau. Most insects eaten by frogs are ordo of Hymenoptera of the family Formicidae. Food composition ratio between the two frog species show that B melanostictus has the highest food composition compared to B. asper.
TL;DR: The authors explored the feeding habits of two populations of the lizard Aspidoscelis lineattissima from two localities (Cocinas = island and Xametla = mainland) under the hypothesis that in an insular environment, there is less selection of food, because it is a relatively comfortable environment to forage due to the presence of few competitors and predators.
Abstract: We explore the feeding habits of two populations of the lizard Aspidoscelis lineattissima from two localities (Cocinas = island and Xametla = mainland) under the hypothesis that in an insular environment, there is less selection of food, because it is a relatively comfortable environment to forage due to the presence of few competitors and predators. We also examine the predator–prey size relationship in this lizard species with the intention of distinguishing possible ontogenetic changes in the choice of prey sizes in the two localities. In stomach contents of the lizards from mainland, a total of 2,616 prey items were recorded, while on the island, 1,357 prey items were found. This number of prey was divided into 18 categories for the mainland and 20 for the island. In general terms, the most important prey in the diet of lizards from both localities were Isoptera, Coleoptera (adult and larvae), Araneae, Orthoptera, Hymenoptera (ants and others), Blattodea, and Diptera. Island lizards presented a greater amount of plant material in their stomach contents. The breadth of the food niche was greater on the island than on the mainland. Although statistically there were no differences regarding food overlap between localities, the highest overlap values between groups (age classes and sexes) were found on the mainland. We found a positive relationship between morphological variables of the lizards (snout–vent length, head width, and head length) with the maximum and mean values of the prey volume in both localities. This reveals an ontogenetic change that indicates that as lizards grow, they add a greater quantity of large prey to their diet and at the same time eat smaller prey. These results showed that the diet of the lizards from both localities was similar to other species of the genus. The feeding habits of a species in contrasting environments is evidence that is helpful for understanding the foraging patterns more clearly, and the possible connection with its life history characteristics, shedding more light on the hypothesis of niche amplitude and the optimal foraging theory.
References
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Book•
01 Jan 1948
TL;DR: The Mathematical Theory of Communication (MTOC) as discussed by the authors was originally published as a paper on communication theory more than fifty years ago and has since gone through four hardcover and sixteen paperback printings.
Abstract: Scientific knowledge grows at a phenomenal pace--but few books have had as lasting an impact or played as important a role in our modern world as The Mathematical Theory of Communication, published originally as a paper on communication theory more than fifty years ago. Republished in book form shortly thereafter, it has since gone through four hardcover and sixteen paperback printings. It is a revolutionary work, astounding in its foresight and contemporaneity. The University of Illinois Press is pleased and honored to issue this commemorative reprinting of a classic.
10,215 citations
TL;DR: In this article, a new multivariate analysis technique, called canonical correspondence analysis (CCA), was developed to relate community composition to known variation in the environment, where ordination axes are chosen in the light of known environmental variables by imposing the extra restriction that the axes be linear combinations of environmental variables.
Abstract: A new multivariate analysis technique, developed to relate community composition to known variation in the environment, is described. The technique is an extension of correspondence analysis (reciprocal averaging), a popular ordination technique that extracts continuous axes of variation from species occurrence or abundance data. Such ordination axes are typically interpreted with the help of external knowledge and data on environmental variables; this two—step approach (ordination followed by environmental gradient identification) is termed indirect gradient analysis. In the new technique, called canonical correspondence analysis, ordination axes are chosen in the light of known environmental variables by imposing the extra restriction that the axes be linear combinations of environmental variables. In this way community variation can be directly related to environmental variation. The environmental variables may be quantitative or nominal. As many axes can be extracted as there are environmental variables. The method of detrending can be incorporated in the technique to remove arch effects. (Detrended) canonical correspondence analysis is an efficient ordination technique when species have bell—shaped response curves or surfaces with respect to environmental gradients, and is therefore more appropriate for analyzing data on community composition and environmental variables than canonical correlation analysis. The new technique leads to an ordination diagram in which points represent species and sites, and vectors represent environmental variables. Such a diagram shows the patterns of variation in community composition that can be explained best by the environmental variables and also visualizes approximately the "centers" of the species distributions along each of the environmental variables. Such diagrams effectively summarized relationships between community and environment for data sets on hunting spiders, dyke vegetation, and algae along a pollution gradient.
5,689 citations
"Niche overlap and resource partitio..." refers methods in this paper
...Relationships between microhabitat and diet and foraging strategy for these five species were tested through a canonical correspondence analysis (CCA) (Ter Braak 1986, 1987)....
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31 Dec 1968
TL;DR: Professor Levins, one of the leading explorers in the field of integrated population biology, considers the mutual interpenetration and joint evolution of organism and environment, occurring on several levels at once.
Abstract: Professor Levins, one of the leading explorers in the field of integrated population biology, considers the mutual interpenetration and joint evolution of organism and environment, occurring on several levels at once. Physiological and behavioral adaptations to short-term fluctuations of the environment condition the responses of populations to long-term changes and geographic gradients. These in turn affect the way species divide the environments among themselves in communities, and, therefore, the numbers of species which can coexist. Environment is treated here abstractly as pattern: patchiness, variability, range, etc. Populations are studied in their patterns: local heterogeneity, geographic variability, faunistic diversity, etc.
3,628 citations
"Niche overlap and resource partitio..." refers methods in this paper
...For numerical data we calculated niche breadth using the Levins Index (Levins 1968): Nb Pij= ∑ −( )2 1 , where Pij represents the probability of finding the item i in the sample j....
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...For numerical data we calculated niche breadth using the Levins Index (Levins 1968):...
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TL;DR: To conclude with a list of questions appropriate for studies of resource partitioning, questions this article has related to the theory in a preliminary way.
Abstract: To understand resource partitioning, essentially a community phenomenon, we require a holistic theory that draws upon models at the individual and population level. Yet some investigators are still content mainly to document differences between species, a procedure of only limited interest. Therefore, it may be useful to conclude with a list of questions appropriate for studies of resource partitioning, questions this article has related to the theory in a preliminary way. 1) What is the mechanism of competition? What is the relative importance of predation? Are differences likely to be caused by pressures toward reproductive isolation? 2) Are niches (utilizations) regularly spaced along a single dimension? 3) How many dimensions are important, and is there a tendency for more dimensions to be added as species number increases? 4) Is dimensional separation complementary? 5) Which dimensions are utilized, how do they rank in importance, and why? How do particular dimensions change in rank as species nuimber increases? 6) What is the relation of dimensional separation to difference in phenotypic indicators? To what extent does the functional relation of phenotype to resource characteristics constrain partitioning? 7) What is the distance between mean position of niches, what is the niche standard deviation, and what is the ratio of the two? What is the niche shape?
3,626 citations
"Niche overlap and resource partitio..." refers background in this paper
...The degree of niche differentiation among species in the same trophic level depends on many factors, been prey availability one of the most relevant (Pianka 1969, Schoener 1974, 1989)....
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TL;DR: The topic here is the structure of lizard communities in this somewhat loose sense of the word (perhaps assemblage would be a more accurate description), with emphasis on the niche relationships among such sympatric sets of lizard species, especially as they affect the numbers of species that coexist within lizard communities.
Abstract: Strictly speaking, a community is composed of all the organisms that live together in a particular habitat. Community structure concerns all the various ways in which the members of such a community relate to and interact with one another, as well as community-level properties that emerge from these interactions, such as trophic structure, energy flow, species diversity, relative abundance, and community stabil ity. In practice, ecologists are usually unable to study entire communities, but instead interest is often focused on some convenient and tractable subset (usually taxonomic) of a particular community or series of communities. Thus one reads about plant communities, fish communities, bird communities, and so on. My topic here is the structure of lizard communities in this somewhat loose sense of the word (perhaps assemblage would be a more accurate description); my emphasis is on the niche relationships among such sympatric sets of lizard species, especially as they affect the numbers of species that coexist within lizard communities (species den sity). So defined, the simplest (and perhaps least interesting) lizard communities would be those that contain but a single species, as, for instance, northern populations of Eumeces msciatus. At the other extreme, probably the most complex lizard commu nities are those of the Australian sandridge deserts where as many as 40 different species occur in sympatry (20). Usually species densities of sympatric lizards vary from about 4 or 5 species to perhaps as many as 20. Lizard communities in arid regions are generally richer in species than those in wetter areas; therefore, because almost all ecological studies of entire saurofaunas have been in deserts (l8, 20, 25), this paper emphasizes the structure of desert lizard communities. As such, I review mostly my own work. Other studies on lizard communities in nondesert habitats are, however, cited where appropriate. Historical factors such as degree of isolation and available biotic stocks (particu larly the species pools of potential competitors and predators) have profoundly shaped lizard communities. Thus one reason the Australian deserts support such very rich lizard communities may be that competition with, and perhaps predation pressures from, snakes, birds, and mammals are reduced on that continent (20).
2,406 citations
"Niche overlap and resource partitio..." refers methods in this paper
...We calculated dietary overlaps in two ways by considering the food proportions and the volume of each prey with the formula (Pianka 1973): O P P P P jk ij ik i n ij ik i n i n = = == ∑ ∑∑ 1 2 2 11 , where Pij and Pik are the proportions of utilization of the ith food resource by the jth and kth…...
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...We calculated dietary overlaps in two ways by considering the food proportions and the volume of each prey with the formula (Pianka 1973):...
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