Scavenger or predator? Examining a potential predator–prey relationship between crayfish and benthic fish in stream food webs

2013 ◽  
Vol 32 (4) ◽  
pp. 1309-1317 ◽  
Author(s):  
Claire L. Thomas ◽  
Christopher A. Taylor
Keyword(s):  
Food Webs ◽  
Benthic Fish ◽  
Potential Predator ◽  
Predator Prey ◽  
Stream Food Webs

scholarly journals Taxonomic Compositions and Co-occurrence Relationships of Protists in Bulk Soil and Rhizosphere of Soybean Fields in Different Regions of China

2021 ◽  
Vol 12 ◽  
Author(s):  
Jun Zhang ◽  
Pengcheng Xing ◽  
Mengyu Niu ◽  
Gehong Wei ◽  
Peng Shi
Keyword(s):  
High Throughput Sequencing ◽  
Niche Overlap ◽  
Spatial Location ◽  
Bulk Soil ◽  
Community Structures ◽  
Potential Predator ◽  
Predator Prey ◽  
Soybean Plants ◽  
Bacteria And Fungi ◽  
Potential Interactions

As the main consumers of bacteria and fungi in farmed soils, protists remain poorly understood. The aim of this study was to explore protist community assembly and ecological roles in soybean fields. Here, we investigated differences in protist communities using high-throughput sequencing and their inferred potential interactions with bacteria and fungi between the bulk soil and rhizosphere compartments of three soybean cultivars collected from six ecological regions in China. Distinct protist community structures characterized the bulk soil and rhizosphere of soybean plants. A significantly higher relative abundance of phagotrophs was observed in the rhizosphere (25.1%) than in the bulk soil (11.3%). Spatial location (R2 = 0.37–0.51) explained more of the variation in protist community structures of soybean fields than either the compartment (R2 = 0.08–0.09) or cultivar type (R2 = 0.02–0.03). The rhizosphere protist network (76 nodes and 414 edges) was smaller and less complex than the bulk soil network (147 nodes and 880 edges), indicating a smaller potential of niche overlap and interactions in the rhizosphere due to the increased resources in the rhizosphere. Furthermore, more inferred potential predator-prey interactions occur in the rhizosphere. We conclude that protists have a crucial ecological role to play as an integral part of microbial co-occurrence networks in soybean fields.

scholarly journals What drives interaction strengths in complex food webs? A test with feeding rates of a generalist stream predator

2018 ◽  
Author(s):  
Daniel L. Preston ◽  
Jeremy S. Henderson ◽  
Landon P. Falke ◽  
Leah M. Segui ◽  
Tamara J. Layden ◽  
...  
Keyword(s):  
Food Webs ◽  
Body Mass ◽  
Prey Density ◽  
Scaling Laws ◽  
Community Dynamics ◽  
Abiotic Factors ◽  
Interaction Strength ◽  
Feeding Rates ◽  
Predator Prey ◽  
Mass Ratios

AbstractDescribing the mechanisms that drive variation in species interaction strengths is central to understanding, predicting, and managing community dynamics. Multiple factors have been linked to trophic interaction strength variation, including species densities, species traits, and abiotic factors. Yet most empirical tests of the relative roles of multiple mechanisms that drive variation have been limited to simplified experiments that may diverge from the dynamics of natural food webs. Here, we used a field-based observational approach to quantify the roles of prey density, predator density, predator-prey body-mass ratios, prey identity, and abiotic factors in driving variation in feeding rates of reticulate sculpin (Cottus perplexus). We combined data on over 6,000 predator-prey observations with prey identification time functions to estimate 289 prey-specific feeding rates at nine stream sites in Oregon. Feeding rates on 57 prey types showed an approximately log-normal distribution, with few strong and many weak interactions. Model selection indicated that prey density, followed by prey identity, were the two most important predictors of prey-specific sculpin feeding rates. Feeding rates showed a positive, accelerating relationship with prey density that was inconsistent with predator saturation predicted by current functional response models. Feeding rates also exhibited four orders-of-magnitude in variation across prey taxonomic orders, with the lowest feeding rates observed on prey with significant anti-predator defenses. Body-mass ratios were the third most important predictor variable, showing a hump-shaped relationship with the highest feeding rates at intermediate ratios. Sculpin density was negatively correlated with feeding rates, consistent with the presence of intraspecific predator interference. Our results highlight how multiple co-occurring drivers shape trophic interactions in nature and underscore ways in which simplified experiments or reliance on scaling laws alone may lead to biased inferences about the structure and dynamics of species-rich food webs.

Predator Ecology

2021 ◽  
Author(s):  
John P. DeLong
Keyword(s):  
Food Webs ◽  
Functional Response ◽  
Behavioral Ecology ◽  
Evolutionary Dynamics ◽  
Ecological Systems ◽  
Ecological Communities ◽  
Functional Responses ◽  
Predator Prey ◽  
Top Predators ◽  
Integrative Science

Predator-prey interactions form an essential part of ecological communities, determining the flow of energy from autotrophs to top predators. The rate of predation is a key regulator of that energy flow, and that rate is determined by the functional response. Functional responses themselves are emergent ecological phenomena – they reflect morphology, behavior, and physiology of both predator and prey and are both outcomes of evolution and the source of additional evolution. The functional response is thus a concept that connects many aspects of biology from behavioral ecology to eco-evolutionary dynamics to food webs, and as a result, the functional response is the key to an integrative science of predatory ecology. In this book, I provide a synthesis of research on functional responses, starting with the basics. I then break the functional response down into foraging components and connect these to the traits and behaviors that connect species in food webs. I conclude that contrary to appearances, we know very little about functional responses, and additional work is necessary for us to understand how environmental change and management will impact ecological systems

scholarly journals Flow intermittency influences the trophic base, but not the overall diversity of alpine stream food webs

Ecography ◽  
2019 ◽  
Vol 42 (9) ◽  
pp. 1523-1535 ◽  
Author(s):  
Andre R. Siebers ◽  
Amael Paillex ◽  
Christopher T. Robinson
Keyword(s):  
Food Webs ◽  
Alpine Stream ◽  
Flow Intermittency ◽  
Stream Food Webs

Impacts of aquatic invasive species and land use on stream food webs in Kaua’i, Hawai’i.

2014 ◽  
Vol 20 (3) ◽  
pp. 252 ◽  
Author(s):  
Megan Layhee ◽  
Michael P. Marchetti ◽  
Sudeep Chandra ◽  
Tag Engstrom ◽  
Daniel Pickard
Keyword(s):  
Invasive Species ◽  
Food Webs ◽  
Introduced Species ◽  
Human Disturbance ◽  
Habitat Degradation ◽  
Community Change ◽  
Ecological Communities ◽  
Native Populations ◽  
Niche Area ◽  
Stream Food Webs

Anthropogenic disturbance is restructuring ecosystems and changing interactions within ecological communities. On the Hawaiʼian Islands, habitat degradation is linked to the establishment of invasive species; and together these stressors may lead to declining native populations and changes in food webs. In this study we employed stable isotopes to examine the structure of multiple Hawaiʼian stream food webs with varying levels of these stressors to illustrate interactions between native and non-native organisms that may represent drivers of community change. Limahuli stream contains all five species of native Hawaiʼian gobies, has a small number of introduced species, and minimal human disturbance. ʻOpaekaʼa, Hul¯eʼia and Kapaʼa streams are more heavily invaded than Limahuli and have greater human influence. We found increased species richness, increased trophic diversity, and increased total niche area in the more heavily invaded stream food webs relative to Limahuli. We also found non-native predatory species inhabiting top trophic positions in the three more heavily invaded streams and isotope mixing model estimates suggest that several species of non-natives have overlapping prey sources with native gobies in these sites. Lastly, we found that native stream organisms were nearly absent in ʻOpaekaʼa stream which also had the highest percent urban development of the streams sampled. Our results suggest significant trophic changes have occurred as the result of introduced species and possibly related to increased human disturbance.

scholarly journals Anthropogenic land-use signals propagate through stream food webs in a California, USA, watershed

Limnologica ◽  
2014 ◽  
Vol 46 ◽  
pp. 124-130 ◽  
Author(s):  
Jonathan W. Moore ◽  
Timothy D. Lambert ◽  
Walter N. Heady ◽  
Susanna E. Honig ◽  
Ann-Marie K. Osterback ◽  
...  
Keyword(s):  
Land Use ◽  
Food Webs ◽  
Anthropogenic Land Use ◽  
Stream Food Webs

Methylmercury Bioaccumulation in Stream Food Webs Declines with Increasing Primary Production

2015 ◽  
Vol 49 (13) ◽  
pp. 7762-7769 ◽  
Author(s):  
David M. Walters ◽  
David F. Raikow ◽  
Chad R. Hammerschmidt ◽  
Molly G. Mehling ◽  
Amanda Kovach ◽  
...  
Keyword(s):  
Primary Production ◽  
Food Webs ◽  
Methylmercury Bioaccumulation ◽  
Stream Food Webs

scholarly journals The importance of high-quality algal food sources in stream food webs - current status and future perspectives

2016 ◽  
Vol 61 (6) ◽  
pp. 815-831 ◽  
Author(s):  
Fen Guo ◽  
Martin J. Kainz ◽  
Fran Sheldon ◽  
Stuart E. Bunn
Keyword(s):  
Food Webs ◽  
Food Sources ◽  
Current Status ◽  
Future Perspectives ◽  
High Quality ◽  
Algal Food ◽  
Stream Food Webs
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