scholarly journals Relating trophic resources to community structure: a predictive index of food availability

2017 ◽  
Vol 4 (2) ◽  
pp. 160515 ◽  
Author(s):  
Valerio Zupo ◽  
Timothy J. Alexander ◽  
Graham J. Edgar
Keyword(s):  
Trophic Group ◽  
Food Abundance ◽  
Trophic Groups ◽  
Predictive Index ◽  
Food Items ◽  
Natural Factors ◽  
Trophic Resources ◽  
Ecological Theories ◽  
Resource Conditions ◽  
Natural Communities

The abundance and the distribution of trophic resources available for consumers influence the productivity and the diversity of natural communities. Nevertheless, assessment of the actual abundance of food items available for individual trophic groups has been constrained by differences in methods and metrics used by various authors. Here we develop an index of food abundance, the framework of which can be adapted for different ecosystems. The relative available food index (RAFI) is computed by considering standard resource conditions of a habitat and the influence of various generalized anthropogenic and natural factors. RAFI was developed using published literature on food abundance and validated by comparison of predictions versus observed trophic resources across various marine sites. RAFI tables here proposed can be applied to a range of marine ecosystems for predictions of the potential abundance of food available for each trophic group, hence permitting exploration of ecological theories by focusing on the deviation from the observed to the expected.

Arthropods in the nests of lesser spotted eagle (Aquila pomarina)

Biologia ◽  
2009 ◽  
Vol 64 (5) ◽  
Author(s):  
Ján Krištofík ◽  
Peter Mašán ◽  
Zbyšek Šustek ◽  
Dušan Karaska
Keyword(s):  
Trophic Group ◽  
Trophic Groups ◽  
Significant Component ◽  
Free Living ◽  
Parasitic Species ◽  
Number Of Species ◽  
Aquila Pomarina ◽  
Investigation Period ◽  
First Time

AbstractIn 2001–2007, altogether 57 nests of lesser spotted eagle were collected in the Orava region in northwestern Slovakia and four groups of arthropods were extracted from them. Richest in number of species and individuals were mites (23 species, 17,500 ind.), followed by beetles (12 species, 725 ind.), whereas pseudoscorpions were represented only by Pselaphochernes scorpioides (39 ind.) and fleas by Ceratophyllus garei (3 ind.). Unlike nests of other birds, free-living mites predominated in the nests fauna (83% of individuals), followed by nidicolous species with more or less free relationship to the nests, while parasitic species represented only a negligible part of the fauna. For the first time we observed phoresy of Nenteria pandioni, a specific and abundant mite in the eagles’ nests, on the nidicolous staphylinid Haploglossa puncticollis. The beetle fauna in the nests was much poorer than in nests of other birds. The predatory H. puncticollis was dominant in the nests (83%) and occurred continuously during the whole investigation period. Other beetles, even the widely distributed nidicols such as the histerid Gnathoncus buyssoni, were found rarely in nests. Predators were also the only abundant trophic group of beetles in the nests, while other trophic groups of beetles abundantly co-occur in nests of majority of other birds. The occurrence of all beetles was very unevenly distributed during the investigation period, but was positively correlated with occurrence of mites. The relatively low number of species and individuals of mites and beetles in the lesser spotted eagle nests resulted from their position on tree tops, at a height of 20–30 m and their quick drying out by sun and wind. It was also indicated by an enormously low number of species and individuals of mycetophagous beetles, which represent a significant component of the fauna in nests of other birds.

Impact of biochar amendment on soil nematode communities in a West African rain-fed rice cropland

Nematology ◽  
2021 ◽  
pp. 1-12
Author(s):  
Segun O. Oladele ◽  
Adebayo Adeyemo ◽  
Moses Awodun ◽  
Ajoke Adegaye ◽  
Mariko Ingold
Keyword(s):  
Trophic Group ◽  
West African ◽  
Nematode Population ◽  
Available Phosphorus ◽  
Soil Nematode ◽  
Trophic Groups ◽  
Nematode Communities ◽  
Study Results ◽  
Inorganic Fertiliser ◽  
Plant Parasitic

Summary Nematode population and diversity in a West African rain-fed rice cropland amended with biochar (B), biochar plus inorganic fertiliser (B + NPK), inorganic fertiliser (NPK) and control (CK) without amendments were investigated in a 3-year field study. Results demonstrated that significant differences exist between treatments and years of study for total nematode population and nematode trophic groups. Total nematode density, nematode trophic group (bacterivore and plant-parasitic) density were increased and dominant in B + NPK compared with CK after 3 years. Relative abundance of nematode genera according to trophic group across treatments showed Hirschmanniella (23%) as the dominant plant parasites in NPK, and Heterocephalobus (27%), Aphelenchoides (22%) and Eudorylaimus (9%) as dominant bacterivores, fungivores and omnivores-predators, respectively, in B + NPK. Trophic group indicators showed that the fungivore plus bacterivore to plant-parasitic ratio (73%) was significantly increased by B + NPK treatment in comparison to CK. Conversely, treatments exerted no significant effect on the fungivore to bacterivore ratio (F/B) throughout the period of study, which implies less disturbance and adverse impact of biochar on nematode communities. Apart from treatments and environmental factors, changes in nematode trophic groups were strongly related to soil chemical properties, such as soil pH, total nitrogen and available phosphorus, which shows their influence on soil nematode community. Our result shows the positive effect of integrated addition of biochar and inorganic fertiliser in balancing nematode diversity and building a resilient soil ecosystem in a low input rain-fed rice cropping system.

Intraspecific variation in opportunistic use of trophic resources by the lizard Ameiva corax (Squamata: Teiidae)

2016 ◽  
Vol 37 (3) ◽  
pp. 331-334 ◽  
Author(s):  
Grace Garrison ◽  
Mia Phillips ◽  
Maria Eifler ◽  
Douglas Eifler
Keyword(s):  
Social Network ◽  
Intraspecific Variation ◽  
Foraging Strategy ◽  
Small Island ◽  
Food Items ◽  
Trophic Resources ◽  
Present Information ◽  
The Social

Ameiva corax is restricted to a small island (<2 ha), off the coast Anguilla. We present information on intraspecific variation in its diet, based on observations of 190 marked individuals. Larger individual were more likely to attempt to enter active seabird nests and only large males were observed to successfully enter a nest and break open an egg. Flower eating was commonly observed and its occurrence was not related to lizard size or sex. More than half the population was observed visiting areas where fisherman mixed their bait, a foraging strategy also unrelated to lizard size or sex. Ameiva corax is known to socially feed at large food items such as seabird eggs. The individuals that can initially access these food items may occupy key roles in the social network.

scholarly journals Habitat diversity and benthic functional trophic groups at Serra do Cipó, Southeast Brazil

2001 ◽  
Vol 61 (2) ◽  
pp. 259-266 ◽  
Author(s):  
M. CALLISTO ◽  
P. MORENO ◽  
F. A. R. BARBOSA
Keyword(s):  
Riparian Vegetation ◽  
Aquatic Macrophytes ◽  
Mesh Size ◽  
Habitat Diversity ◽  
Trophic Groups ◽  
Macroinvertebrate Communities ◽  
Lotic Ecosystems ◽  
Serra Do Cipó ◽  
Trophic Resources ◽  
Doce River

The assessment of the diversity of habitats and the characterisation of the functional trophic groups of benthic macroinvertebrate communities of some rivers of Serra do Cipó (MG) were the main objectives of this study. The available trophic resources and the types of substrata were characterised along with the structure and composition of their using functional trophic groups. Serra do Cipó is a watershed divisor of the São Francisco and Doce River basins, including a series of streams and rivers, of good water quality and well preserved ecological characteristics. Samples were collected in Cipó, Peixe and Preto do Itambé rivers, besides the Indaiá and Capão da Mata streams at 26 sampling stations, during the rainy (February) and dry (October) seasons of 1998, using "Kicking nets" of 0.125 mm mesh size. The group of collectors (Baetidae, Leptophlebiidae and Leptohyphidae) was the most abundant, followed by collector-predators (Hydrophilidae, Ceratopogonidae, Chironomidae-Tanypodinae), and detritivorous-herbivores (Oligochaeta). The riparian vegetation, together with the aquatic macrophytes, are the substrata containing the highest richness of functional trophic groups and the higher habitat diversity. The results suggest that the use of functional trophic groups, together with habitat evaluation, are efficient tools in the evaluation of the diversity of benthic macroinvertebrates, particularly in altitudinal lotic ecosystems.

scholarly journals Predicting the sign of trophic effects: individual-based simulation versus loop analysis

2021 ◽  
Vol 22 (3) ◽  
pp. 441-451
Author(s):  
Virág Fábián
Keyword(s):  
Food Web ◽  
Interaction Strength ◽  
Trophic Group ◽  
Structural Features ◽  
Trophic Levels ◽  
Trophic Groups ◽  
Analysis Model ◽  
Natural Ecosystems ◽  
Loop Analysis ◽  
Simple Loop

AbstractFood web research needs to be predictive in order to support decisions system-based conservation. In order to increase predictability and applicability, complexity needs to be managed in such a way that we are able to provide simple and clear results. One question emerging frequently is whether certain perturbations (environmental effects or human impact) have positive or negative effects on natural ecosystems or their particular components. Yet, most of food web studies do not consider the sign of effects. Here, we study 6 versions of the Kelian River (Borneo) food web, representing six study sites along the river. For each network, we study the signs of the effects of a perturbed trophic group i on each other j groups. We compare the outcome of the relatively complicated dynamical simulation model and the relatively simple loop analysis model. We compare these results for the 6 sites and also the 14 trophic groups. Finally, we see if sign-agreement and sign-determinacy depend on certain structural features (node centrality, interaction strength). We found major differences between different modelling scenarios, with herbivore-detritivore fish behaving in the most consistent, while algae and particulate organic matter behaving in the least consistent way. We also found higher agreement between the signs of predictions for trophic groups at higher trophic levels in sites 1–3 and at lower trophic levels in site 4–6. This means that the behaviour of predators in the more natural sections of the river and that of producers at the more human-impacted sections are more consistently predicted. This suggests to be more careful with the less consistently predictable trophic groups in conservation management.

scholarly journals Phenotypic Plasticity in Vertebrate Dentitions

2020 ◽  
Vol 60 (3) ◽  
pp. 608-618
Author(s):  
Nidal Karagic ◽  
Axel Meyer ◽  
C Darrin Hulsey
Keyword(s):  
Phenotypic Plasticity ◽  
Potential Role ◽  
Tooth Structure ◽  
Food Items ◽  
Trophic Resources ◽  
Genetic Mechanisms

Synopsis Vertebrates interact directly with food items through their dentition, and these interactions with trophic resources could often feedback to influence tooth structure. Although dentitions are often considered to be a fixed phenotype, there is the potential for environmentally induced phenotypic plasticity in teeth to extensively influence their diversity. Here, we review the literature concerning phenotypic plasticity of vertebrate teeth. Even though only a few taxonomically disparate studies have focused on phenotypic plasticity in teeth, there are a number of ways teeth can change their size, shape, or patterns of replacement as a response to the environment. Elucidating the underlying physiological, developmental, and genetic mechanisms that generate phenotypic plasticity can clarify its potential role in the evolution of dental phenotypes.

scholarly journals Chironomidae larvae (Diptera) of Neotropical floodplain: overlap niche in different habitats

2014 ◽  
Vol 74 (2) ◽  
pp. 363-370 ◽  
Author(s):  
CMM. Butakka ◽  
FH. Ragonha ◽  
AM. Takeda
Keyword(s):  
Organic Matter ◽  
Alimentary Canal ◽  
Food Resource ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Trophic Groups ◽  
Food Items ◽  
Trophic Networks ◽  
Chironomidae Larvae ◽  
Neotropical Floodplain

The niche overlap between trophic groups of Chironomidae larvae in different habitats was observed between trophic groups and between different environments in Neotropical floodplain. For the evaluation we used the index of niche overlap (CXY) and analysis of trophic networks, both from the types and amount of food items identified in the larval alimentary canal. In all environments, the larvae fed on mainly organic matter such as plants fragments and algae, but there were many omnivore larvae. Species that have high values of food items occurred in diverse environments as generalists with great overlap niche and those with a low amount of food items with less overlap niche were classified as specialists. The largest number of trophic niche overlap was observed among collector-gatherers in connected floodplain lakes. The lower values of index niche overlap were predators. The similarity in the diet of different taxa in the same niche does not necessarily imply competition between them, but coexistence when the food resource is not scarce in the environment even in partially overlapping niches.

scholarly journals To feed or to breed: morphological constraints of mouthbrooding in coral reef cardinalfishes

2012 ◽  
Vol 279 (1737) ◽  
pp. 2426-2432 ◽  
Author(s):  
Andrew S. Hoey ◽  
David R. Bellwood ◽  
Adam Barnett
Keyword(s):  
Evolutionary History ◽  
Reproductive Potential ◽  
Trophic Group ◽  
Functional Coupling ◽  
Trophic Groups ◽  
Feeding Apparatus ◽  
Evolutionary Diversification ◽  
Trophic Morphology ◽  
Ideal System ◽  
Tightly Coupled

Functionally coupled biomechanical systems are widespread in nature and are viewed as major constraints on evolutionary diversification, yet there have been few attempts to explore the implications of performing multiple functions within a single anatomical structure. Paternally mouthbrooding cardinalfishes present an ideal system to investigate the constraints of functional coupling as the oral jaws of male fishes are directly responsible for both feeding and reproductive functions. To test the effects of (i) mouthbrooding on feeding and (ii) feeding on reproductive potential we compared the feeding apparatus between sexes of nine species of cardinalfish and compared brood characteristics among species from different trophic groups, respectively. Mouthbrooding was strongly associated with the morphology of the feeding apparatus in males. Male cardinalfishes possessed longer heads, snouts and jaws than female conspecifics irrespective of body size, trophic group or evolutionary history. Conversely, reproductive potential also appeared to be related to trophic morphology. Piscivorous cardinalfishes produced larger, but fewer eggs, and had smaller brood volumes than species from the two invertebrate feeding groups. These interrelationships suggest that feeding and reproduction in the mouth of cardinalfishes may be tightly coupled. If so this may, in part, have contributed to the limited morphological diversification exhibited by cardinalfishes.

scholarly journals Functional trophic groups and spatial variation of aquatic insects in a hydrographic basin of Southern Brazil

2018 ◽  
Vol 5 (3) ◽  
pp. 50
Author(s):  
Mario Arthur Favretto ◽  
Elton Orlandin ◽  
Emili Bortolon Dos Santos ◽  
Osvaldo Onghero-Jr.
Keyword(s):  
Spatial Variation ◽  
Aquatic Insects ◽  
Human Impacts ◽  
Trophic Group ◽  
Environmental Conservation ◽  
Trophic Groups ◽  
Southern Brazil ◽  
Heterogeneous Distribution ◽  
Environmental Evaluation ◽  
Hydrographic Basin

In Brazil hydrographic basins are geographical unities used to environmental and hydric resources management, but few studies focus in the biodiversity variation within these unities. Here we present the results of spatial variation of aquatic insects in streams of a hydrographic basin in Southern Brazil. The insect composition was analyzed in relation to abundance of the families, functional trophic group and environmental evaluation indexes proposed by literature. The insects had a heterogeneous distribution in the sampling areas of the hydrographic basin. The most abundant families were Hydropsychidae, Philopotamidae and Leptophlebiidae, which demonstrate a good oxygenation of the water in the sampling streams. The most abundant functional trophic groups were gatherer-collector (20%) and scraper (18.92%). The indexes demonstrated the riverbeds of the streams are stable, with a high presence of fine particulate organic matter and they were considered heterotrophic. However, they also indicated a low abundance of shredders, which may be related to poor environmental conditions in the riparian forests. Therefore, here we found spatial variation of aquatic insects and indexes performed indicated the main human impacts as deforestation and inadequate land use. The data obtained also contributed to reinforce the importance of hydrographic basin as geographical unities for environmental conservation.

scholarly journals Nematode communities in greenhouse soil of different ages from Shenyang suburb

2006 ◽  
Vol 43 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Y. Liu ◽  
J. Hua ◽  
Y. Jiang ◽  
Q. Li ◽  
D. Wen
Keyword(s):  
Community Structure ◽  
Organic Carbon ◽  
Soil Depth ◽  
Trophic Group ◽  
Trophic Groups ◽  
Total Abundance ◽  
Greenhouse Soil ◽  
Nematode Communities ◽  
Plant Parasite ◽  
Different Ages

AbstractThe distribution of nematode communities with depth in greenhouse soil of different ages from Shenyang suburb was investigated in October 2004. Thirteen families and 23 genera were observed in our study. Heterocephalobus was dominant genus in all treatments. The numbers of total nematodes and trophic groups declined with soil depth but increased with greenhouse age. Bacterivores were the most abundant trophic group in all treatments, followed by plant parasites and omnivores-predators, while fungivores were the least, only accounted for less than 4 % of the total abundance. Maturity index (MI) and plant parasite index (PPI) were effective in distinguishing differences in nematode community structure in different ages of greenhouses. The numbers of total nematodes were positively correlated with soil organic carbon, total nitrogen, nitrate, and electrolytic conductivity, but negatively with soil pH.

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