21 |
Influences of a <i>Cladophora</i> Bloom on the Diets of <i>Amblema Plicata </i>and <i>Elliptio Dilatata</i> in the Upper Green River, KentuckyYates, Jennifer Maria 01 December 2012 (has links)
Freshwater mussels are the most imperiled group of freshwater invertebrates globally. Recent research suggests a better understanding of mussel feeding ecology may facilitate and improve conservation efforts. The use of stable isotopes is becoming an increasingly common method to study aquatic food webs. Carbon (C) and nitrogen (N) are two of the most frequently employed elements in food web studies. Differences in natural abundance of 13C/12C can indicate which food sources are the basal sources of carbon incorporated into a consumer’s tissue, while the ratio of 15N /14N provides a method of assessing trophic position within a food web. Attached macroalgae, including the genus Cladophora, may be the dominant primary producers in running water systems. Cladophora, however, has not yet been indicated as a prominent assimilated food source for freshwater mussels. The overall purpose of this study was to assess if the diet of two common Green River mussel species, Amblema plicata (Say) and Elliptio dilatata (Rafinesque) were influenced by the seasonal change in availability of Cladophora during a summer-autumn rapid growth period. Two specific questions were asked: 1) Are the assimilated diets different between control and treatment areas, and 2) are the assimilated diets influenced by differing Cladophora levels across the study period? A mesocosm approach was employed in order to manipulate Cladophora levels within a treatment area. Seventy-two mussels, 36 each species, were sampled across four months,twice between control (= reach-scale, heavy Cladophora cover) and treatment (= localscale removal of Cladophora) areas. The freeware program, IsoSource, a concentration weighted linear mixing model, was used to determine the potential contribution of potential food sources to the diet of both mussel species. IsoSource revealed that Cladophora was the primary assimilated food source for both species across the study period. Although assimilated diets were not different between control and treatment areas, diets were, however, influenced by Cladophora availability across time. The results of this study indicate that, during bloom conditions, Cladophora is the primary carbon source for both A. plicata and E. dilatata and may form the base of food webs in the upper Green River.
|
22 |
Ecologia Trófica de Pimelodella lateristriga (Osteichthyes, Siluriformes) do rio Mato Grosso, Saquarema - RJ / Trophic ecology of Pimelodella lateristriga (Osteichthyes, Siluriformes) do rio Mato Grosso, Saquarema - RJ.Maíra Moraes Pereira 24 February 2010 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Este trabalho teve como objetivo descrever variações espaço-temporais e ontogenéticas na dieta de Pimelodella lateristriga Lichtenstein 1823) no rio Mato Grosso, Saquarema RJ. Os trechos de coleta foram escolhidos pelas suas diferenças na conservação da vegetação ripária, sendo as coletas realizadas bimestralmente de março/2006 a janeiro/2007, utilizando pesca-elétrica e arrastinho. A dissertação foi dividida em dois capítulos. O primeiro capítulo referiu-se a variações espaço-temporais da dieta, onde constataram-se diferenças no número (maior na localidade fechada) e tamanho (maior na localidade aberta) dos itens consumidos pela espécie nas localidades de estudo. Na localidade fechada a espécie se alimentou de um maior número de itens, porém menores quanto na localidade aberta a espécie se alimentou de um menor número de itens, porém maiores. Apesar dessas diferenças o hábito alimentar (onívoro com tendência a insetivoria) se manteve, independentemente da localidade e da época do ano. O segundo capítulo referiu-se a variação ontogenética na
dieta da espécie. Foram encontradas diferenças em relação ao comprimento do intestino, ao uso de recursos alóctones e autóctones por jovens e adultos, com o predomínio no consumo de itens autóctones pelos jovens, e em relação ao tamanho
dos itens ingeridos, onde os jovens consumiram itens menores do que os adultos. Concluiu-se que P. lateristriga do rio Mato Grosso possui dieta onívora com tendência a insetivoria, possui variação espacial na dieta em relação ao número e tamanho dos
itens consumidos, não possui variação sazonal na dieta, pois não encontrou-se padrão na utilização de itens de diferentes natureza em relação aos meses de estudo e também que a espécie possui variação ontogenética na dieta. / This work aims to describe various aspects of the feeding ecology of Pimelodella lateristriga (Lichtenstein 1823) related to the spatial and temporal variations and ontogenetic on Mato Grosso stream, Saquarema - RJ. The collecting sites were
according to their different degrees of conservation of riparian vegetation. Samples were collected bimonthly from March/2006 to January 2007, using electricfishing and sieves.The dissertation was divided into two chapters, where each one deals with one aspect of the diet of the species. The first chapter deals with spatial and temporal variations of the diet, where we found differences in the number and size of items consumed by the species in two separate locations, but the feeding habits of the species omnivorous with a tendency to insectivory) was maintained regardless of location. The second chapter deals with ontogenetic shifts in the diet of the species. Differences in intestine length were observed, also in the use of allochthonous and autochthonous resources by young and adults individuals, with predomination of autochthonus items for young. The size of ingested items, was also different, with the young consuming smaller items than adults. We conclude that P. lateristriga of Mato Grosso stream has an omnivorous diet, with a tendency to insectivory, has spatial variation in diet in relation to the number and size of items consumed, has no seasonal variation in diet, since we found no pattern of use of items of different nature in relation to months of study and that the species has ontogenetic diet shifts.
|
23 |
Padrões de distribuição e organização trófica da assembleia de peixes no estuário do Rio Mamanguape, Paraíba, BrasilMedeiros, Aline Paiva Morais de 12 February 2016 (has links)
Submitted by João Henrique Costa (henrique@biblioteca.ufpb.br) on 2016-12-19T14:32:19Z
No. of bitstreams: 1
Arquivototal.pdf: 2635026 bytes, checksum: 13eda8fbce0b59e5bba1b505be4cfed4 (MD5) / Made available in DSpace on 2016-12-19T14:32:19Z (GMT). No. of bitstreams: 1
Arquivototal.pdf: 2635026 bytes, checksum: 13eda8fbce0b59e5bba1b505be4cfed4 (MD5)
Previous issue date: 2016-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The present study aimed to characterize a fish assemblage along a mangrove-reef gradient at Barra do Rio Mamanguape Environmental Protected Area, Paraíba, Brazil, according to the following parameters: spatial distribution, habitat use, feeding ecology and trophic guilds. This dissertation is divided in two chapters: the first one aims to describe the spatial and seasonal distribution, habitat use and ontogenetic shifts on estuary usage; the second one registers fish diet according to region, season and size classes of most abundant species as well as the trophic. Fish samples were gathered using three types of nets along seventeen sites, grouped in four regions according to salinity range: Reefs, Low, Middle and Upper estuaries. Most abundant species were Atherinela brasiliensis and Sphoeroides testudineus. Among the guilds, piscivores were the most abundant, followed by crab eaters. Herbivores were found with higher abundance in reefs. We registered differences in guilds distribution along the mangrove-reef gradient and according to seasons (dry and rainy). Caranx latus, Oligoplites palometa and Mugil curema occupied different regions in different life stages. We registered differences in guilds distribution along the mangrove-reef gradient and according to seasons (dry and rainy). / O presente trabalho objetivou caracterizar a ictiofauna ao longo de um gradiente estuarino-recifal na APA Barra do Rio Mamanguape, Paraíba, Brasil, utilizando os seguintes parâmetros: distribuição espacial, uso do habitat, dieta e formação de grupos tróficos. O trabalho foi dividido em dois capítulos, onde o primeiro trata da distribuição espaço-temporal, uso do habitat e mudanças ontogenéticas no uso do estuário; o segundo, descreve a dieta das espécies e registra a formação de grupos tróficos, bem como a dieta das espécies abundantes de acordo com o local e estação em que foram coletadas e pelas classes de tamanho. Foram utilizados arrastos, tarrafas e agulheiras a fim de coletar os peixes e a dieta foi determinada a partir da análise dos conteúdos gástricos. As coletas foram realizadas ao longo de 17 pontos, divididos em quatro regiões a partir do gradiente de salinidade: Recifes, Baixo Estuário, Estuário Médio e Alto Estuário. As espécies mais abundantes foram Atherinela brasiliensis e Sphoeroides testudineus. A maior média de tamanho dos indivíduos foi registrada para a zona recifal, a qual apresentou uma maior contribuição de herbívoros em relação às regiões do estuário. Espécies como Caranx latus, Oligoplites palometa e Mugil curema apresentaram diferenças na preferência do habitat ao conforme ontogenia. A maior parte das espécies registradas no presente estudo foi considerada de origem marinha, podendo depender direta ou indiretamente do estuário. Em relação aos grupos tróficos, o grupo com maior número de representantes foram os Piscívoros, seguidos pelos que se alimentaram de Brachyura. A distribuição dos grupos tróficos também apresentou entre as regiões amostradas e também sazonalmente.
|
24 |
Ecologia Trófica de Pimelodella lateristriga (Osteichthyes, Siluriformes) do rio Mato Grosso, Saquarema - RJ / Trophic ecology of Pimelodella lateristriga (Osteichthyes, Siluriformes) do rio Mato Grosso, Saquarema - RJ.Maíra Moraes Pereira 24 February 2010 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Este trabalho teve como objetivo descrever variações espaço-temporais e ontogenéticas na dieta de Pimelodella lateristriga Lichtenstein 1823) no rio Mato Grosso, Saquarema RJ. Os trechos de coleta foram escolhidos pelas suas diferenças na conservação da vegetação ripária, sendo as coletas realizadas bimestralmente de março/2006 a janeiro/2007, utilizando pesca-elétrica e arrastinho. A dissertação foi dividida em dois capítulos. O primeiro capítulo referiu-se a variações espaço-temporais da dieta, onde constataram-se diferenças no número (maior na localidade fechada) e tamanho (maior na localidade aberta) dos itens consumidos pela espécie nas localidades de estudo. Na localidade fechada a espécie se alimentou de um maior número de itens, porém menores quanto na localidade aberta a espécie se alimentou de um menor número de itens, porém maiores. Apesar dessas diferenças o hábito alimentar (onívoro com tendência a insetivoria) se manteve, independentemente da localidade e da época do ano. O segundo capítulo referiu-se a variação ontogenética na
dieta da espécie. Foram encontradas diferenças em relação ao comprimento do intestino, ao uso de recursos alóctones e autóctones por jovens e adultos, com o predomínio no consumo de itens autóctones pelos jovens, e em relação ao tamanho
dos itens ingeridos, onde os jovens consumiram itens menores do que os adultos. Concluiu-se que P. lateristriga do rio Mato Grosso possui dieta onívora com tendência a insetivoria, possui variação espacial na dieta em relação ao número e tamanho dos
itens consumidos, não possui variação sazonal na dieta, pois não encontrou-se padrão na utilização de itens de diferentes natureza em relação aos meses de estudo e também que a espécie possui variação ontogenética na dieta. / This work aims to describe various aspects of the feeding ecology of Pimelodella lateristriga (Lichtenstein 1823) related to the spatial and temporal variations and ontogenetic on Mato Grosso stream, Saquarema - RJ. The collecting sites were
according to their different degrees of conservation of riparian vegetation. Samples were collected bimonthly from March/2006 to January 2007, using electricfishing and sieves.The dissertation was divided into two chapters, where each one deals with one aspect of the diet of the species. The first chapter deals with spatial and temporal variations of the diet, where we found differences in the number and size of items consumed by the species in two separate locations, but the feeding habits of the species omnivorous with a tendency to insectivory) was maintained regardless of location. The second chapter deals with ontogenetic shifts in the diet of the species. Differences in intestine length were observed, also in the use of allochthonous and autochthonous resources by young and adults individuals, with predomination of autochthonus items for young. The size of ingested items, was also different, with the young consuming smaller items than adults. We conclude that P. lateristriga of Mato Grosso stream has an omnivorous diet, with a tendency to insectivory, has spatial variation in diet in relation to the number and size of items consumed, has no seasonal variation in diet, since we found no pattern of use of items of different nature in relation to months of study and that the species has ontogenetic diet shifts.
|
25 |
Ecologia alimentar de Zoanthus sociatus e Protopalythoa variabilis (Cnidaria: Zoantharia) no litotal de Pernambuco, BrasilALVES, Amanda Lacerda 26 March 2015 (has links)
Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-08-09T13:09:24Z
No. of bitstreams: 1
Amanda Lacerda Alves.pdf: 932884 bytes, checksum: f27ca0558b921d57172b3fae91cc1191 (MD5) / Made available in DSpace on 2016-08-09T13:09:24Z (GMT). No. of bitstreams: 1
Amanda Lacerda Alves.pdf: 932884 bytes, checksum: f27ca0558b921d57172b3fae91cc1191 (MD5)
Previous issue date: 2015-03-26 / This study investigated the feeding ecology of zoanthids Zoanthus sociatus and Protopalythoa variabilis. Colonies of this species were sampled in the infralittoral zone of reefs in northeastern Brazil (may/2013 to february/2014). Polyps (n = 400) were examined the gastric cavity and prey found were counted, measured and identified. We calculated the richness and total abundance of prey items. The GLM test two-way ANOVA was used to compare the abundance and ricness between period and species. The biovolume of preys were calculated to characterize the most important food items in terms of their biomasses. To evaluate the selectivity, zoanthid and plankton samples were collected in the dry season and rainy. The results revealed the occurrence of seven taxa of phytoplankton and zooplankton three, and particulate organic matter. Pennales diatoms were the most abundant and most frequent prey and, together with invertebrate eggs, constituted the most important food items in terms of their biomasses. There were significant differences in abundance and richness among the species and between periods, with a significant interaction between these factors, only for abundance. The mean size of prey items within the polyps of Z. sociatus (26.35 ± 59.10 μm) and polyps of P. variabilis (26.56 ± 54.71 μm) was significantly smaller than in the plankton (54,14 ± 107,25 μm). As for the type prey, Zoanthus sociatus and Protopalythoa variabilis feed predominantly diatoms. The results, the two species are suspensívoras, feeding mainly on small phytoplankton. These results corroborate those previously found for the zoanthid P. caribaeorum in the same place, showing that this group has an important role in energy flow in reefs, transferring biomass of plankton to superiroes groups of the chain. This is fundamental to the Brazilian reefs where coverage of other suspensívoros as coral, is very low. / Este trabalho objetivou estudar a ecologia alimentar dos zoantídeos Zoanthus sociatus e Protopalythoa variabilis. Foram amostradas trimestralmente (maio/2013 a fevereiro/2014) colônias das espécies no infralitoral nos recifes da Praia de Porto de Galinhas (8º 33’ 00’’ a 8°33’33” S ; 35º 00’27’’ a 34º 59’ 00’’ W). Os pólipos (n=400) tiveram a cavidade gástrica examinada e as presas encontradas foram contabilizadas, medidas e identificadas. Foram calculadas a riqueza e abundância total dos itens de presas. O teste GLM two-way ANOVA foi usado para comparar a abundância e riqueza entre período e espécies. A partir das medições das presas, foi calculado o biovolume para caracterizar as presas com maior importância no aporte de biomassa. Para análise de seletividade foram coletadas amostras das espécies de zoantídeos e do plâncton no período seco e chuvoso. Os resultados revelaram a ocorrência de sete taxons do fitoplâncton e três do zooplâncton, além de matéria orgânica particulada. As diatomáceas pennales foram as presas mais abundantes e, juntamente, com ovos de invertebrados constituíram as presas mais importantes no aporte de biomassa. Houve diferença significativa na abundância e riqueza entre as espécies e entre os períodos, havendo interação significativa entre estes fatores, apenas para a abundância. O tamanho médio das presas presentes nos pólipos de Z. sociatus (26,35 ± 59,10 μm) e nos pólipos de P. variabilis (26,56 ± 54,71 μm) foi menor do que no plâncton (54,14 ± 107,25 μm). Quanto ao tipo de presa, Zoanthus sociatus e Protopalythoa variabilis se alimentam predominantemente de diatomáceas. Pelos resultados obtidos, as duas espécies são suspensívoras, alimentando-se principalmente de fitoplancton de pequeno porte. Esses resultados corroboram os anteriormente encontrados para o zoantídeo P. caribaeorum no mesmo local, demonstrando que este grupo tem um papel importantíssimo no fluxo de energia nos recifes, transferindo biomassa do plâncton para elos superiroes da cadeia. Isto é fundamental para os recifes brasileiros onde a cobertura de outros suspensívoros, como corais, é muito baixa.
|
26 |
Feeding Ecology and Habitat Utilization of the Great Barracuda Sphyraena barracuda (Edwards 1771) in Southeast FloridaHansen, Noah R. 01 January 2015 (has links)
Great barracuda Sphyraena barracuda is a large predatory teleost found circumglobally, other than the Eastern Pacific Ocean. The species is commonly caught by both recreational and commercial fishermen as bycatch while targeting other, more economically or recreationally valuable fishes. This species also exhibits an ontogenetic shift in habitat, with juveniles inhabiting mangrove and seagrass habitats, while adults live near offshore reefs and associated structure.
This thesis consists of two separate studies of S. barracuda: 1) feeding ecology along an ontogenetic gradient and 2) habitat utilization of as derived through electronic tagging. The first chapter of this thesis describes the feeding ecology of great barracuda in South Florida, with an emphasis on the determination of when the ontogenetic shift in diet occurs between habitats and individual fish sizes. Specimens were collected primarily by seine net and hook-and-line fishing. The specimens were then dissected with the stomach contents examined. This study found that the ontogenetic diet shift in great barracuda begins around the second year, and that juveniles and adults are opportunistic predators with a wide diversity of teleost and crustacean prey items within the selected habitat. The second chapter of this thesis describes the habitat utilization and vertical movements of two great barracuda off of South Florida interpreted from data acquired from pop-up satellite archival tags (PSATs). This study found that large (>100 cm) great barracuda are capable of travelling hundreds of kilometers over a period of days to weeks. The results show that large great barracuda can tolerate temperatures ranging from 17.8° C to 31.3° C, and are capable of diving to depths greater than 175 m. It was also found that there was a significant difference in time spent at depth, with greater depths being inhabited more frequently at night.
|
27 |
Diet of the Antillean Manatee (Trichechus manatus manatus) in Belize, Central AmericaAllen, Aarin Conrad 01 January 2014 (has links)
Belize has been identified as an important location for Antillean manatees (Trichechus manatus manatus), harboring the highest known population density of this subspecies. Information about their dietary habit is important in determining habitat requirements and aiding in conservation efforts. The main objective of this study was to identify the key plant species consumed by manatees in Belize and to establish differences in diet based on location, sex, size classification, and season. Samples were collected from two different locations within Belize where manatees are known to aggregate: Southern Lagoon and the Drowned Cayes off of Belize City. The contents of thirteen mouth, six digestive tract (stomach, duodenum and colon), and 124 fecal samples were analyzed. Five species of seagrasses (Halodule wrightii, Thalassia testudinum, Ruppia maritima, Syringodium filiforme, and Halophila sp.) made up the highest percentage of plants consumed; undigested rhizome was most prevalent. A vascular plant, the red mangrove (Rhizophora mangle), was identified as an important food item of manatees in Belize. Algae (Chara sp., Lyngbia sp., and Ulvasp.) and invertebrates (diatoms and sponges) were represented as well. These items are comparable to other reports of manatee diets in areas near Belize and areas with similar habitat. Variation in the percentage of seagrass, mangrove, and algae consumption was analyzed as a 4-factor factorial Analysis of Variance (ANOVA) with main effects and interactions for locality (Southern Lagoon and the Drowned Cayes), sex, size classification (>245 cm & ˂245 cm), and season (December – May and June – November). Sex and season did not influence diet composition; differences for locality and size classification were observed. Seagrass was more often consumed in Southern Lagoon (P = 0.03), whereas mangroves and algae were more prevalent in the Drowned Cayes (P = 0.03). No differences among size classifications in consumption of seagrasses or mangroves were observed. A significantly higher number of samples from adults (>245 cm) than juveniles (˂245 cm) contained algae (P = 0.04). This is most likely attributed to inexperience in foraging. Findings from these results suggest that diet composition analysis can be used to interpret Antillean manatee habitat and resource utilization and can aid in the conservation of this endangered species.
|
28 |
Impacts of a specialist diet on aardwolf ecologyDe Vries, J.L. 07 1900 (has links)
The diet of an animal plays a fundamental role in its ecology, and the consequence of a specific diet may be more pronounced in mammals with a specialised diet that are more reliant on a specific food type. This can have a dramatic effect on its activity patterns, home range size and the interaction with heterospecifics. Investigating the diet of specialist mammals and the subsequent effects it will have on their ecology is thus vital to the management and subsequent conservation of the species, and crucial to our understanding of how the animal can survive and reproduce. In this thesis I investigate the effect that the diet of the aardwolf, a highly specialised myrmecophage, has on its ecology. Aardwolves feed predominantly on one genus of termite, Trinervoides spp., and are thus extremely dependent on the abundance and distribution of this arthropod. I firstly investigated the effect of temperature and rainfall on arthropod abundance and diversity, and further investigated the variation of arthropod abundance and diversity across the four habitat types at study site. This is one of a few studies that have been conducted on arthropod abundance and diversity in an arid environment and the findings show that in an arid environment arthropods are mainly influenced by temperature rather than rainfall. This is in contrast to studies in temperate and forest habitats where rainfall is the most important abiotic factor determining the abundance and diversity of arthropod assemblages. Habitat type still plays a major role in the abundance and diversity of arthropods, and habitat types that are more complex and diverse have both a higher diversity, and abundance of arthropods than other habitats. Due to the absence of prey items during the colder months of the year I investigated the diet of aardwolves to see if they display a switch in diet. This included an investigation into the seasonal variation of diet from a detailed scat analysis, using a newly developed method to assess scat content. The analysis of scats revealed that, contrary to previous studies, aardwolves showed no switch in diet and continued to feed on Trinervitermes. Using the data from the scat analyses and the information from the abundance and diversity of arthropods at the study site I expanded the study to investigate the functional responses of the aardwolf to change in prey abundance at the locality. Aardwolves demonstrate a Type I functional response to changes in prey abundance, a response that is normally found in plankton feeders. The expected functional response for specialist animals would be Type II response, and I propose that the Type I response seen in aardwolves is probably as a result of a limited handling time which reduces time spent foraging. The abundance of termites thus had a clear effect on the diet of aardwolves, showing that they feed on fewer when they are unavailable, and as such I investigated the effect of termite densities on home range sizes. The number of termite mounds in a home range influenced the size of the home range, and aardwolves with larger home ranges had a lower density of termite mounds. In contrast to previous studies, large overlaps between neighbouring individuals were recorded and indeed three male aardwolves shared a common den. I propose that the reason behind the overlap of home ranges is that a higher prey abundance during my study period occurred and as a consequence aardwolves did not need to defend an area to protect this resource. T. trinervoides has thus played a keystone role in driving the biology of the aardwolf and shaping many aspects of its ecology. / Thesis (PhD)--University of Pretoria, 2021. / South African Research Chair Initiative chair of Mammal Behavioural Ecology and Physiology / Zoology and Entomology / PhD / Unrestricted
|
29 |
Using faecal DNA to investigate the diet of the snakes, Psammophis crucifer and Psammophylax rhombeatusScholtz, Kim Jennilee January 2022 (has links)
>Magister Scientiae - MSc / Knowledge of the feeding ecology of an organism helps us to better understand predator-prey relationships and aspects of species biology, ecology and life-history traits. Understanding the feeding ecologies of snakes is challenging because snakes are generally secretive and often difficult to observe when foraging in the wild. Traditionally, studies attempting to quantify the diets of snakes relied on observing direct predation events, dissecting dead specimens, or microscopy of gut and stomach contents to identify prey species. However, investigations using traditional methods can result in an incomplete understanding of prey utilised by particular snakes. Analysis of prey DNA in snake faeces is a useful method to obtain accurate information on diet.
|
30 |
Aspects of the Feeding Ecology of the Bonneville Cisco of Bear Lake, Utah-IdahoLentz, David C. 01 May 1986 (has links)
The Bonneville cisco (Prosopium gemmiferum), a small planktivorous whitefish, is an important part of the distinctive fish community of Bear Lake, Utah-Idaho. The Bonneville cisco plays a key role in the trophic structure by converting zooplankton to fish biomass and providing a major forage sour ce for cutthroat and lake trout. Aspects of cisco feeding ecology studied include characterization of the zooplankton community composition and dynamics and cisco feeding habits and prey select ion.
|
Page generated in 0.0815 seconds