Trophic position and potential food sources of 2 species of unionid bivalves (Mollusca:Unionidae) in 2 small Ohio streams

The fast increase in temperature on the Tibetan Plateau, with anticipated future changes in aquatic ecosystems and biodiversity, highlights the urgent need for ecological data on the sparsely studied Tibetan running waters. In the present study we surveyed eight Tibetan streams to obtain data on densities, feeding selectivity and trophic position of the stone loach Triplophysa. Benthic algae, detritus, macroinvertebrates and fish were quantified and collected for stable isotope and stomach content analysis. Triplophysa density (mean 0.70 individuals m–2, maximum 1.6 individuals m–2) decreased with altitude and increased with the percentage cover of fine substratum. Glacier-fed sites tended to have the lowest fish densities, whereas the highest densities were found near lakes. Mean fish length (4.1–9.6cm) was positively related to the percentage cover of coarse substratum. Triplophysa was omnivorous, but the composition of the stomach contents varied greatly between sites and among individuals. Algal matter was ingested at most sites, but macroinvertebrates (Chironomidae, Baetidae and Simuliidae) dominated the ingestion (average 50–100%). The trophic position of Triplophysa, identified from δ15N (‰) of the biota, varied between 2.6 and 4.2 among localities (mean 3.6) and was inversely related to the biomass of benthic algae, but unrelated to quantities of other potential food sources.

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Effects of Cyclone Waka on flying foxes (Pteropus tonganus) in the Vava'u Islands of Tonga

Journal of Tropical Ecology ◽

10.1017/s0266467404001804 ◽

2004 ◽

Vol 20 (5) ◽

pp. 555-561 ◽

Cited By ~ 23

Author(s):

Kim R. McConkey ◽

Donald R. Drake ◽

Janet Franklin ◽

Filipe Tonga

Keyword(s):

Secondary Forest ◽

Vegetation Type ◽

Cocos Nucifera ◽

Absolute Number ◽

Food Sources ◽

Primary Forest ◽

Flying Foxes ◽

Pteropus Tonganus ◽

Potential Food ◽

Flying Fox

Severe tropical cyclones are a major cause of episodic mortality for Pacific Island flying foxes (large fruit bats). Many flying foxes starve after forests are stripped of food sources, and hunting by humans may also increase in the post-cyclone period. In December 2001, Cyclone Waka passed directly over the Vava'u Islands in the Kingdom of Tonga, western Polynesia. We visited the islands 6 mo later to survey the flying fox (Pteropus tonganus) population and assess availability of potential food items (fruit and flower) in primary, secondary and plantation forests. Less than 20% of the pre-cyclone bat population (surveyed in 1999–2001) remained 6 mo after the storm. The density of potential food trees in flower or fruit at this time was only 15% of pre-cyclone density, and the main species available were different in the two time periods. The highest density of potential food trees occurred in secondary forest (26 flowering or fruiting trees ha−1) and plantations (23 ha−1); primary forest offered the least food (18 ha−1). Since 65–70% of the land area has been converted to agricultural plantations, this vegetation type had the highest absolute number of food-bearing trees – almost seven times that of primary forest. Flowering coconuts (Cocos nucifera) were the most abundant food source overall and we suggest that this species may be important in sustaining flying foxes following severe storms.

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CONSUMO DE RESÍDUOS AGRÍCOLAS E URBANOS PELO DIPLÓPODE Trigoniulus corallinus

Nativa ◽

10.31413/nativa.v7i2.6192 ◽

2019 ◽

Vol 7 (2) ◽

pp. 162

Author(s):

Luiz Fernando De Sousa Antunes ◽

Rafael Nogueira Scoriza ◽

Dione Galvão da Silva ◽

Maria Elizabeth Fernandes Correia

Keyword(s):

Organic Matter ◽

Organic Agriculture ◽

Food Preferences ◽

Dry Mass ◽

Food Sources ◽

Banana Tree ◽

Consumption Rates ◽

Potential Food

Os diplópodes são capazes de ingerir serapilheira parcialmente decomposta, transformando-a em matéria orgânica que enriquece o solo. Este trabalho objetivou avaliar potenciais fontes alimentares dos diplópodes da espécie Trigoniulus corallinus em laboratório fornecendo diferentes resíduos na forma de serrapilheira não decomposta, por um período de dez dias. Os resíduos utilizados neste experimento (todos senescentes) foram: aparas de grama batatais; folhas de gliricídia; de flemingia; de pata de vaca; de bananeira, além de um resíduo industrializado, neste caso, pedaços de papelão picado. O delineamento utilizado foi inteiramente casualizado, com dez repetições. Ao final de dez dias foram avaliados os seguintes parâmetros: massa seca do resíduo restante da alimentação dos diplópodes, massa seca dos coprólitos e mortalidade dos diplópodes. A mensuração das taxas de consumo dos diplópodes mostraram-se diferentes entre os tratamentos, sendo as maiores taxas observadas para as folhas de flemingia (25,4 %) seguido pelas folhas de gliricídia (21,2 %). A massa de coprólitos gerados foi maior a partir dos resíduos de flemingia (0,214 g) e foi ausente na presença de papelão e gliricídia. Observou-se 100% de mortalidade dos diplópodes após o consumo de folhas de gliricídia. Depreende-se dos resultados que diplópodes da espécie T. corallinus são capazes de ingerir resíduos pobres em nutrientes, porém exibem nitidamente preferência alimentar por resíduos que contenham maiores teores de nutrientes.Palavras-chave: gongolos, compostagem, agricultura orgânica. CONSUMPTION OF AGRICULTURAL AND URBAN WASTES BY THE DIPLOPODA Trigoniulus corallinus ABSTRACT: Diplopods are able to ingest litter partially decomposed, transforming them into organic matter that enrich the soil. This work aimed to evaluate potential food sources of the dipropods of the specie Trigoniulus corallinus in the laboratory providing different residues in the form of non - decomposed litter for a period of ten days. The residues used in this experiment (all senescent) were: batatais grass cuttings; Gliricidia leaves; of Flemingia; of cow's foot; of banana tree, in addition to an industrialized residue, in this case pieces of cardboard. The design was completely randomized, with ten replications. At the end of ten days, the following parameters were evaluated: dry mass of the remaining diplopods feed, dry mass of coprolites and mortality of diplopods. The measurement of the consumption rates of the diplopods were different among the treatments, with the highest rates observed for the leaves of flemingia (25.4%) followed by the leaves of gliricidia (21.2%). The mass of generated coprolites was higher from the flemingia residues (0.214 g) and was absent in the presence of cardboard and gliricidia. It was observed 100% mortality of the diplopods after consumption of gliricidia leaves. It appears from the results that dipropods of T. corallinus species are able to ingest nutrient-poor residues, but clearly exhibit their food preferences for residues containing higher nutrient contents.Keywords: millipedes, composting, organic agriculture.

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Plastic and unpredictable responses of stream invertebrates to leaf pack patches across sandy-bottomed streams

Marine and Freshwater Research ◽

10.1071/mf10314 ◽

2011 ◽

Vol 62 (4) ◽

pp. 394 ◽

Cited By ~ 14

Author(s):

Barbara J. Downes ◽

Jill Lancaster ◽

Robin Hale ◽

Alena Glaister ◽

William D. Bovill

Keyword(s):

Food Sources ◽

Stream Invertebrates ◽

Patch Use ◽

Leaf Pack ◽

Bare Sand ◽

Eastern Australia ◽

Type Ii Errors ◽

Potential Food ◽

Power Analyses

Detrital inputs to ecosystems provide potential food sources and can produce trophic cascades, but this effect is influenced by whether species specialise in consuming or inhabiting accumulations of detritus. To test whether species are differentially associated with leaves or sand, we compared densities of stream invertebrate species in patches of leaves and bare sand in two sandy-bed creeks in south-eastern Australia, in summer and spring. We also assessed the quality of information on diet and substrate association in the literature. Most species showed no density differences between leaf and sand patches (‘microhabitat generalists’), but categorisation as generalists, leaf or sand species differed between datasets. We developed a method for identifying important effect sizes; power analyses showed that many species were true generalists, but many non-significant results were potentially Type II errors. The literature provided information that was broadly consistent with our data, but few studies publish reliable information about either diet or patch use. Our results support a contention that few Australian stream invertebrates are obligate shredders, and this may also be true for streams elsewhere. Predicting and detecting the responses of such generalist taxa to detrital inputs will be very challenging.

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EFFECTS OF DIFFERENT POTENTIAL FOOD SOURCES ON UPPER-BATHYAL BENTHIC FORAMINIFERA: AN EXPERIMENT WITH PROPAGULES

The Journal of Foraminiferal Research ◽

10.2113/gsjfr.44.4.416 ◽

2014 ◽

Vol 44 (4) ◽

pp. 416-433 ◽

Cited By ~ 10

Author(s):

C. J. Duffield ◽

B. Edvardsen ◽

W. Eikrem ◽

E. Alve

Keyword(s):

Benthic Foraminifera ◽

Food Sources ◽

Potential Food

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Mercury Contamination in Riverine Sediments and Fish Associated with Artisanal and Small-Scale Gold Mining in Madre de Dios, Peru

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph15081584 ◽

2018 ◽

Vol 15 (8) ◽

pp. 1584 ◽

Cited By ~ 20

Author(s):

Gerardo Martinez ◽

Stephen McCord ◽

Charles Driscoll ◽

Svetoslava Todorova ◽

Steven Wu ◽

...

Keyword(s):

Gold Mining ◽

Trophic Position ◽

Mercury Contamination ◽

Food Sources ◽

Small Scale ◽

Habitat Conditions ◽

Ecological Processes ◽

Madre De Dios ◽

Fish Samples ◽

Δ15n And Δ13c

Artisanal and small-scale gold mining (ASGM) in Madre de Dios, Peru, continues to expand rapidly, raising concerns about increases in loading of mercury (Hg) to the environment. We measured physicochemical parameters in water and sampled and analyzed sediments and fish from multiple sites along one ASGM-impacted river and two unimpacted rivers in the region to examine whether Hg concentrations were elevated and possibly related to ASGM activity. We also analyzed the 308 fish samples, representing 36 species, for stable isotopes (δ15N and δ13C) to estimate their trophic position. Trophic position was positively correlated with the log-transformed Hg concentrations in fish among all sites. There was a lack of relationship between Hg concentrations in fish and either Hg concentrations in sediments or ASGM activity among sites, suggesting that fish Hg concentrations alone is not an ideal bioindicator of site-specific Hg contamination in the region. Fish Hg concentrations were not elevated in the ASGM-impacted river relative to the other two rivers; however, sediment Hg concentrations were highest in the ASGM-impacted river. Degraded habitat conditions and commensurate shifts in fish species and ecological processes may influence Hg bioaccumulation in the ASGM-impacted river. More research is needed on food web dynamics in the region to elucidate any effects caused by ASGM, especially through feeding relationships and food sources.

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