scholarly journals Resource use and coexistence of two syntopic hylid frogs (Anura, Hylidae)

2005 ◽  
Vol 22 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Marcelo Menin ◽  
Denise de C. Rossa-Feres ◽  
Ariovaldo A. Giaretta
Keyword(s):  
Resource Use ◽  
Resource Partitioning ◽  
Niche Breadth ◽  
Reproductive Season ◽  
Seasonal Occurrence ◽  
Temporary Pond ◽  
Site Characteristics ◽  
Structural Differences ◽  
Time Periods

The objectives of this study were to measure and compare niche breadth and overlap of males of Hyla nana Boulenger, 1889 and Hyla sanborni Schmidt, 1944 in three neighboring ponds. The measured niche dimensions were seasonal occurrence, call site, and diet. The reproductive season of H. sanborni was longer in permanent ponds, whereas H. nana had a longer reproductive season in the temporary pond. Call site characteristics were similar for both species, however H. sanborni called from higher perches than H. nana. Diptera (Nematocera) were the most consumed item by both species in the three ponds but, in general, H. nana ingested larger prey than H. sanborni. For both species, the consumption of prey types was correlated with the availability in the environment. The multidimensional overlap between H. nana and H. sanborni was higher in the permanent ponds than the temporary pond, in which H. sanborni was rare. These species differed in abundance among ponds, consumed prey of different sizes, and probably fed in different time periods. Moreover, the data obtained suggest that structural differences in the ponds may modify the dynamics of resource partitioning between the two species. Beside the great overlap found in the major niche dimensions analyzed the detected differences may be great enough to allow their coexistence.

Resource partitioning along three niche dimensions in a size-structured tropical fish assemblage

1999 ◽  
Vol 56 (7) ◽  
pp. 1241-1254 ◽  
Author(s):  
G J Piet ◽  
J S Pet ◽  
WAHP Guruge ◽  
J Vijverberg ◽  
WLT Van Densen
Keyword(s):  
Resource Use ◽  
Resource Partitioning ◽  
Niche Breadth ◽  
Niche Overlap ◽  
Three Dimensions ◽  
Tropical Fish ◽  
Tropical Reservoir ◽  
Temporal Dimension ◽  
Before And After ◽  
Important Fish

In Tissawewa, a tropical reservoir, the size-specific resource use of the 10 most important fish species was determined along three dimensions: trophic, spatial, and temporal. During this study, a drought occurred distinguishing two periods before and after the drought that differed markedly in availability of resources and fish biomass. In this study, differences in resource use between the two periods are presented together with their consequence on the partitioning of resources. A different approach is introduced into the calculation of niche breadth and niche overlap incorporating size-specific differences in resource use and interactions between resource dimensions. Comparison with conventional measures of niche breadth and niche overlap shows that conventional measures often misrepresent interactions between species. Condition and biomass were used as indicators of a species' fitness, and it is shown that fitness of most species is governed by the availability of resources and partitioning of these resources is an important mechanism allowing potential competitors to coexist. Resource partitioning along the trophic dimension was more important than along the spatial or temporal dimension.

scholarly journals Damming in the Madeira River modifies the food spectrum of piscivorous and affects their resource partitioning

2021 ◽  
Vol 19 (3) ◽  
Author(s):  
Alessandra Pasian Lonardoni ◽  
Cristhiana Paula Röpke ◽  
Taís Melo ◽  
Gislene Torrente-Vilara
Keyword(s):  
Resource Partitioning ◽  
Species Coexistence ◽  
Niche Breadth ◽  
Interspecific Interactions ◽  
Species Abundance ◽  
Hydroelectric Power Plant ◽  
Hydroelectric Power ◽  
Stomach Fullness ◽  
Congeneric Species ◽  
Madeira River

Abstract Phylogenetic proximity suggests some degree of diet similarity among species. Usually, studies of diet show that species coexistence is allowed by partitioning food resources. We evaluate how visually oriented piscivorous fishes (Characiformes) share prey before and after building the Santo Antônio Hydroelectric Power Plant (HPP) in the Madeira River (Brazil), the largest muddy-water tributary of the Amazon River. Piscivorous species (Acestrorhynchus falcirostris, Acestrorhynchus heterolepis, Hydrolycus scomberoides, and Rhaphiodon vulpinus) were sampled under pristine (pre-HPP) and disturbed (post-HPP) environmental conditions. We analyzed species abundance and stomach contents for stomach fullness and prey composition to check variations between congeneric and non-congeneric species. The percent volume of prey taxa was normalized by stomach fullness and grouped into the taxonomic family level to determine diet, niche breadth, and overlap. Only R. vulpinus abundance increased in post-HPP. There was no significant variation in niche breadth between the periods, while niche overlap decreased in congeneric and non-congeneric species. Our results indicate that river impoundment affected piscivorous fishes in distinct ways and modified their resource partitioning. Therefore, evaluate interspecific interactions is a required tool to understand how fishes respond to river damming.

scholarly journals Species-Specific Traits Rather Than Resource Partitioning Mediate Diversity Effects on Resource Use

PLoS ONE ◽  
2009 ◽  
Vol 4 (10) ◽  
pp. e7423 ◽  
Author(s):  
Jasmin A. Godbold ◽  
Rutger Rosenberg ◽  
Martin Solan
Keyword(s):  
Resource Use ◽  
Resource Partitioning ◽  
Species Specific ◽  
Diversity Effects

scholarly journals Resource use by two electric fishes (Gymnotiformes) of the National Forest Saracá-Taquera, Oriximiná, Pará

2017 ◽  
Vol 15 (2) ◽  
Author(s):  
Bruno E. Soares ◽  
Daniela C. O. Rosa ◽  
Nathália C. S. Silva ◽  
Miriam P. Albrecht ◽  
Érica P. Caramaschi
Keyword(s):  
Resource Use ◽  
Niche Breadth ◽  
Feeding Strategy ◽  
Stomach Contents ◽  
Niche Overlap ◽  
Feeding Strategies ◽  
National Forest ◽  
Microhabitat Use ◽  
Use Patterns ◽  
Head Morphology

ABSTRACT Fishes of the order Gymnotiformes have high diversity of oral and head morphology, which suggests trophic specializations within each clade. The aim of this study was to describe resource use patterns by two fish species (Gymnorhamphichthys rondoni and Gymnotus coropinae) in the National Forest Saracá-Taquera, Oriximiná - Pará, analyzing microhabitat use, diet composition, feeding strategies, niche breadth and niche overlap. Stomach contents of 101 individuals (41 G. rondoni and 60 G. coropinae), sampled in 23 headwater streams were analyzed and volume of food items was quantified to characterize their feeding ecology. Gymnorhamphichthys rondoni was captured mainly on sandy bottoms, whereas G. coropinae in crevices. Both species had a zoobenthivorous diet and consumed predominantly Sediment/Detritus and Diptera larvae, but also included allochthonous prey in their diet. These species had high niche overlap, with small variations related to the higher consumption of Ceratopogonidae larvae by G. rondoni and of Chironomidae larvae by G. coropinae. Both species had a generalist feeding strategy, but G. coropinae had a broader niche breadth. Our results demonstrate that G. rondoni and G. coropinae occupy different microhabitats but rely on similar food resources.

Resource partitioning within a browsing guild in a key habitat, the Chobe Riverfront, Botswana

2005 ◽  
Vol 21 (6) ◽  
pp. 641-649 ◽  
Author(s):  
Shimane W. Makhabu
Keyword(s):  
Plant Species ◽  
Resource Use ◽  
Resource Partitioning ◽  
Woody Species ◽  
Food Resources ◽  
Dry Season ◽  
Population Increase ◽  
Species Identity ◽  
Plant Parts ◽  
Elephant Population

Resource partitioning between elephant, giraffe, kudu and impala was assessed. This was to address concerns that elephant population increase adversely affects other species through depleting their food in key areas close to permanent water. Resources considered were woody species browsed, height browsed and plant parts browsed. Animals were observed as they browsed and the plant species, browsing heights and plant parts browsed were recorded. Observations were made over 1 y and the data were divided between wet and dry season. Schoener's index of resource use overlap was calculated for plant species, browsing heights and plant parts eaten and differences in overlap between wet and dry season were tested. Levin's measure of niche breadth in plant species utilized by the different browsers was calculated. Woody species identity was the main separator between food resources that elephant used and those giraffe, impala and kudu used. Giraffe, kudu and impala mainly browsed the same species and plant parts but browsed at different heights. There was no difference in resource use overlap between seasons with different resource availability. Since elephant browsed different woody species from those browsed by the others, it is unlikely that the increasing elephant population will deplete food resources for the other browsers.

Resource use within the crab-eating guild of the upper Kairezi River, Zimbabwe

1996 ◽  
Vol 12 (4) ◽  
pp. 475-490 ◽  
Author(s):  
James R. A. Butler ◽  
Brian E. Marshall
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Resource Use ◽  
Intraguild Predation ◽  
Aquatic Insects ◽  
Prey Item ◽  
Resource Partitioning ◽  
Food Resource ◽  
Dry Season ◽  
Invertebrate Drift

ABSTRACTCape clawless otters Aonyx capensis and African mottled eels Anguilla bengalensis were suspected of reducing numbers of rainbow trout Oncorhynchus mykiss in the upper Kairezi River, Zimbabwe, by preying on them and competing for the river crab Potamon perlatus. The analysis of otter, eel and trout diets showed that this is unlikely. Trout was an unimportant prey item for otters, none were found in the stomachs of 13 large eels, and any predation was probably minimised by the low densities of these predators. Some competition was probably present because crabs occurred in the diets of otters (relative occurrence 41.9%), eels (63.2%) and trout (7.4%), but it was impossible to quantify. Since these predators shared the crab food resource, the guild concept provided the basis for an analysis of their potential competitive relationships. Comparisons between the sizes of crabs selected and those available suggested that resource partitioning was occurring. Trout selected small crabs from the invertebrate drift, and because they were restricted by their mouth gapes. Otters and large eels ate larger, more abundant crab sizes; it is proposed that they instead partition resources spatially by feeding in separate micro-habitats. Intraguild predation by otters on eels may benefit trout by reducing competition for aquatic insects. Competition within the guild probably recedes in the dry season, when eels become inactive.

scholarly journals Intraspecific Competition and the Promotion of Ecological Specialization

2021 ◽  
Author(s):  
Abdel H. Halloway ◽  
Joel S. Brown
Keyword(s):  
Resource Use ◽  
Intraspecific Competition ◽  
Niche Breadth ◽  
Evolutionary Model ◽  
Ecological Specialization ◽  
Secondary Resources ◽  
Cast Doubt ◽  
The Face ◽  
Game Theoretic ◽  
Diversification Hypothesis

AbstractThe evolution of ecological specialization can be summed up in a single question: why would a species evolve a more-restricted niche space? Various hypotheses have been developed to explain the promotion or suppression of ecological specialization. One hypothesis, competitive diversification, states that increased intraspecific competition will cause a population to broaden its niche breadth. With individuals alike in resource use preference, more individuals reduce the availability of preferred resources and should grant higher fitness to those that use secondary resources. However, recent studies cast doubt on this hypothesis with increased intraspecific competition reducing niche breadth in some systems. We present a game-theoretic evolutionary model showing greater ecological specialization with intraspecific competition under specific conditions. This is in contrast to the competitive diversification hypothesis. Our analysis reveals that specialization can offer a competitive advantage. Largely, when facing weak competition, more specialized individuals are able to acquire more of the preferred resources without greatly sacrificing secondary resources and therefore gain higher fitness. Only when competition is too great for an individual to significantly affect resource use will intraspecific competition lead to an increased niche breadth. Other conditions, such as a low diversity of resources and a low penalty to specialization, help promote ecological specialization in the face of intraspecific competition. Through this work, we have been able to discover a previously unseen role that intraspecific competition plays in the evolution of ecological specialization.

Ecology of Euphausiids in the Gulf of St. Lawrence

1976 ◽  
Vol 33 (9) ◽  
pp. 1894-1905 ◽  
Author(s):  
F. Berkes
Keyword(s):  
Resource Partitioning ◽  
Phytoplankton Bloom ◽  
Distribution Patterns ◽  
Reproductive Season ◽  
The Other ◽  
Species Pairs ◽  
Vertical Distributions ◽  
Oceanic Species ◽  
Food And Feeding ◽  
Meganyctiphanes Norvegica

Geographical and vertical distributions, reproduction, growth and maturity, food and feeding of Meganyctiphanes norvegica, Thysanoessa raschii, T. inermis, and T. longicaudata in the Gulf of St. Lawrence were studied, based on plankton samples from 10 cruises, largely from 2 consecutive yr. Adults of the first three species occurred most abundantly in the western Gulf and their larvae in the Magdalen Shallows. By contrast, T. longicaudata, an oceanic species, occurred mainly in the eastern Gulf year-round. All four species reached reproductive maturity at 1 yr of age; all but T. longicaudata populations contained at least two breeding year-classes. The three Thysanoessa species started spawning in April at the time of the phytoplankton bloom; M. norvegica was a summer breeder. All four species were omnivorous, but M. norvegica and T. longicaudata stomachs contained relatively more animal matter than those of the other two. These findings were supported by studies on the morphology of feeding appendages.Thysanoessa longicaudata was differentiated from the other species mainly on the basis of distribution patterns, and M. norvegica from the remaining two mainly on the basis of differences in feeding and reproductive season. In contrast to relatively clear resource partitioning in five of the six species pairs, only relatively small differences in the stomach content composition in winter samples, the spacing of setules, and the length of the breeding season differentiated T. inermis from T. raschii.

Resource partitioning among African savanna herbivores in North Cameroon: the importance of diet composition, food quality and body mass

2011 ◽  
Vol 27 (5) ◽  
pp. 503-513 ◽  
Author(s):  
H. H. de Iongh ◽  
C. B. de Jong ◽  
J. van Goethem ◽  
E. Klop ◽  
A. M. H. Brunsting ◽  
...  
Keyword(s):  
Body Mass ◽  
Diet Quality ◽  
Resource Partitioning ◽  
Diet Composition ◽  
Niche Breadth ◽  
Dry Season ◽  
Niche Separation ◽  
Wet Season ◽  
Herbivore Species ◽  
The Relationship

Abstract:The relationship between herbivore diet quality, and diet composition (the range of food plants consumed) and body mass on resource partitioning of herbivores remains the subject of an ongoing scientific debate. In this study we investigated the importance of diet composition and diet quality on resource partitioning among eight species of savanna herbivore in north Cameroon, with different body mass. Dung samples of four to seven wild herbivore and one domesticated species were collected in the field during the dry and wet period. Diet composition was based on microhistological examination of herbivore droppings, epidermis fragments were identified to genus or family level. In addition, the quality of the faecal droppings was determined in terms of phosphorus, nitrogen and fibre concentrations. The results showed that there was no significant correlation between body mass and (differences in) diet composition for wet and dry season. When all species are considered, only significant relationships are found by the Spearman rank correlation analyses during the wet season between body mass and phosphorus and nitrogen, but this relationship did not exist during the dry season. When the analyses focuses on ruminants only (thus leaving out hippo), none of the relationships between body mass and diet quality was significant in either season. During the dry season the proportion of graminoids ranged between 10% (small unidentified herbivore species) to 90% (hippopotamus), during the wet season this proportion ranged from 60% (zebu) to 90% (hippopotamus). All species but zebu had more graminoids in their dung during wet season compared with dry season. However all species but hartebeest had more graminoids old stems in their dung during the dry season, compared with the wet season. The niche breadth for food categories consumed by kob (0.300), hippo (0.090), hartebeest (0.350), roan (0.510) and zebu (0.300) was much greater in the dry season than in the wet season for kob (0.120), hippo (0.020), hartebeest (0.190), roan (0.090) and zebu (0.200). When looking at grass taxa consumed, the niche breadth of kob (0.220), hartebeest (0.140), and roan (0.250) was also greater in the dry season when compared with the wet season for kob (0.050), hartebeest (0.120) and roan (0.120). The opposite was found for zebu and hippo. Comparison of the species’ diet compositions with randomized data showed that dietary overlap between different herbivore species was much higher than what would be expected on the basis of chance, demonstrating surprisingly limited niche separation between species. This offers potential for competition, but it is more likely that the high niche overlap indicates absence of competition, due to low herbivore densities and abundant food resources, permitting species to share non-limiting resources. With increasing herbivore densities and subsequent increasing scarcity of resources, the relationship between diet quality and body mass in combination with increased niche separation is expected to become more visible.

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