Trait-based predation suitability offers insight into effects of changing prey communities

Increasing environmental pressures and human impacts are reshaping community structures and species interactions throughout all trophic levels. The morphological and behavioural characteristics of species communities contain key ecological information on why prey species appear attractive to predators but are rarely applied when exploring predator-prey (PP) relationships. Expanding our knowledge on how changing prey communities can alter the food resource suitability (RS) for predators is vital for understanding PP dynamics in changing ecosystems. Detailed predator diet data are commonly restricted to commercially important species and often not available over long temporal scales. To find out whether structural changes of prey communities impact the food RS for predator communities over space and time, we apply a novel framework to describe and interpret changes in predator diet-suitability based on predation-relevant traits of prey. We use information on described feeding links from the literature to compile the prey spectrum for each predator and subsequently translate the prey-species into a prey-trait spectrum. For each predator, we then calculate a frequency-based prey-trait affinity score and relate it to the available food resource pool, the community weighted means of prey traits, resulting in a prey-suitability measure. We aim to reveal whether a described multi-decadal change in the community structure of zoobenthos had an impact on the food suitability for the benthic-feeding fish in a coastal system of the Baltic Sea. We assess the direction of change in resource quality from the perspective of benthic-feeding fish and describe predator-specific responses to examine which species are likely to profit or be disadvantaged by changes in their prey spectrum. Furthermore, we test the relationship between functional diversity of prey communities and food suitability for predators, and whether predation linkage-structures are affected through prey community-changes. Our results show that changes in zoobenthic communities had a positive effect on the food suitability for most benthic-feeding fish, implying more suitable food resources. Species-specific responses of predators suggest varying plasticity to cope with prey assemblages of different trait compositions. Additionally, the functional diversity of zoobenthos had a positive effect on the food suitability for predator fish. The changing trait compositions of prey influenced the PP linkage-structure, indicating varying specialisation of benthic feeding fish towards available food resources. Our findings suggest that changing morphological characteristics of prey can impact food RS features for its predators. This approach enables long-term evaluation of prey quality characteristics where no detailed diet data is available and allows for cross-system comparison as it is not relying on taxonomic identities per se.

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Trophic Cascades in Grasslands

10.1093/oso/9780198744511.003.0005 ◽

2018 ◽

Author(s):

Brian J. Wilsey

Keyword(s):

Indirect Effects ◽

Prey Species ◽

Trophic Levels ◽

Herbaceous Plant ◽

Direct Effects ◽

Temperate Grasslands ◽

Cascading Effect ◽

Top Predators ◽

Invertebrate Predators ◽

Ecology Of Fear

Top predators have effects that can ‘cascade down’ on lower trophic levels. Because of this cascading effect, it matters how many trophic levels are present. Predators are either ‘sit and wait’ or ‘active’. Wolves are top predators in temperate grasslands and can alter species composition of smaller-sized predators, prey, and woody and herbaceous plant species, either through direct effects or indirect effects (‘Ecology of Fear’). In human derived grasslands, invertebrate predators fill a similar ecological role as wolves. Migrating populations of herbivores tend to be more limited by food than non-migratory populations. The phenology and synchrony of births vary among prey species in a way that is consistent with an adaptation to predation. Precocious species have highly synchronous birth dates to satiate predators. Non-precocious species (‘hiders’) have asynchronous births. Results from studies that manipulate both predators and food support the hypothesis that bottom-up and top-down effects interact.

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Functional diversity alters the effects of a pulse perturbation on the dynamics of tritrophic food webs

10.1101/2021.03.22.436420 ◽

2021 ◽

Author(s):

Ruben Ceulemans ◽

Laurie Anne Myriam Wojcik ◽

Ursula Gaedke

Keyword(s):

Food Web ◽

Food Webs ◽

Functional Diversity ◽

Feedback Loop ◽

Environmental Changes ◽

Biodiversity Loss ◽

Trophic Levels ◽

Nutrient Pulse ◽

Trade Offs ◽

Food Web Model

Biodiversity decline causes a loss of functional diversity, which threatens ecosystems through a dangerous feedback loop: this loss may hamper ecosystems' ability to buffer environmental changes, leading to further biodiversity losses. In this context, the increasing frequency of climate and human-induced excessive loading of nutrients causes major problems in aquatic systems. Previous studies investigating how functional diversity influences the response of food webs to disturbances have mainly considered systems with at most two functionally diverse trophic levels. Here, we investigate the effects of a nutrient pulse on the resistance, resilience and elasticity of a tritrophic---and thus more realistic---plankton food web model depending on its functional diversity. We compare a non-adaptive food chain with no diversity to a highly diverse food web with three adaptive trophic levels. The species fitness differences are balanced through trade-offs between defense/growth rate for prey and selectivity/half-saturation constant for predators. We showed that the resistance, resilience and elasticity of tritrophic food webs decreased with larger perturbation sizes and depended on the state of the system when the perturbation occured. Importantly, we found that a more diverse food web was generally more resistant, resilient, and elastic. Particularly, functional diversity dampened the probability of a regime shift towards a non-desirable alternative state. In addition, despite the complex influence of the shape and type of the dynamical attractors, the basal-intermediate interaction determined the robustness against a nutrient pulse. This relationship was strongly influenced by the diversity present and the third trophic level. Overall, using a food web model of realistic complexity, this study confirms the destructive potential of the positive feedback loop between biodiversity loss and robustness, by uncovering mechanisms leading to a decrease in resistance, resilience and elasticity as functional diversity declines.

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Diet seasonality and food overlap of the fish assemblage in a pantanal pond

Neotropical Ichthyology ◽

10.1590/s1679-62252008000400004 ◽

2008 ◽

Vol 6 (4) ◽

pp. 567-576 ◽

Cited By ~ 61

Author(s):

Gisele Caroline Novakowski ◽

Norma Segatti Hahn ◽

Rosemara Fugi

Keyword(s):

Fish Assemblage ◽

Food Resource ◽

Fish Fauna ◽

Diet Breadth ◽

Food Resources ◽

Dry Season ◽

Trophic Guilds ◽

Trophic Specialization ◽

Mato Grosso ◽

Mean Values

We assessed the trophic structure of the fish fauna in Sinhá Mariana pond, Mato Grosso State, from March 2000 to February 2001. The aim was to determine the feeding patterns of the fish species during the rainy and dry seasons. The diets of 26 species (1,294 stomach contents) were determined by the volumetric method. Insects and fish were the most important food resources: insects were the dominant food of 23% and 27% of the species, respectively, in the rainy and dry season, and fish was the dominant item for 31% of the species in both seasons. Cluster analysis (Euclidean Distance) identified seven trophic guilds in the rainy season (detritivores, herbivores, insectivores, lepidophages, omnivores, piscivores and planktivores), and five trophic guilds in the dry season (detritivores, insectivores, lepidophages, omnivores and piscivores). The smallest mean values of diet breadth were observed for the specialist guilds (detritivores, lepidophages and piscivores), in both seasons. The widest means for diet breadth were observed for the omnivores, regardless of the season. In general, there was no seasonal variation in feeding overlap among the species studied. At the community level, diet overlap values between species were low (< 0.4) for 80% of the pairs in each season, suggesting wide partitioning of the food resource. The fish assemblage showed a tendency toward trophic specialization, regardless of the season, although several species changed their diets. We might consider two non-excludent hypothesis: that there is no pattern on the use of seasonal food resources and/or probably there are several patterns, because each one is based on characteristics of the studied site and the taxonomic composition of the resident species.

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A First Glimpse on Cold-Adapted PCB-Oxidizing Bacteria in Edmonson Point Lakes (Northern Victoria Land, Antarctica)

Water ◽

10.3390/w14010109 ◽

2022 ◽

Vol 14 (1) ◽

pp. 109

Author(s):

Maria Papale ◽

Angelina Lo Giudice ◽

Alessandro Ciro Rappazzo ◽

Maurizio Azzaro ◽

Carmen Rizzo

Keyword(s):

Human Impacts ◽

Current Knowledge ◽

Freshwater Ecosystems ◽

Trophic Levels ◽

Cold Adapted ◽

Remote Areas ◽

Victoria Land ◽

Long Lifetime ◽

Aroclor 1242 ◽

Edmonson Point

Antarctic freshwater ecosystems are especially vulnerable to human impacts. Polychlorobiphenyls (PCBs) are persistent organic pollutants that have a long lifetime in the environment. Despite their use having either been phased out or restricted, they are still found in nature, also in remote areas. Once in the environment, the fate of PCBs is strictly linked to bacteria which represent the first step in the transfer of toxic compounds to higher trophic levels. Data on PCB-oxidizing bacteria from polar areas are still scarce and fragmented. In this study, the occurrence of PCB-oxidizing cold-adapted bacteria was evaluated in water and sediment of four coastal lakes at Edmonson Point (Northern Victoria Land, Antarctica). After enrichment with biphenyl, 192 isolates were obtained with 57 of them that were able to grow in the presence of the PCB mixture Aroclor 1242, as the sole carbon source. The catabolic gene bphA, as a proxy for PCB degradation potential, was harbored by 37 isolates (out of 57), mainly affiliated to the genera Salinibacterium, Arthrobacter (among Actinobacteria) and Pusillimonas (among Betaproteobacteria). Obtained results enlarge our current knowledge on cold-adapted PCB-oxidizing bacteria and pose the basis for their potential application as a valuable eco-friendly tool for the recovery of PCB-contaminated cold sites.

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Microbial bioenergetics of coral-algal interactions

PeerJ ◽

10.7717/peerj.3423 ◽

2017 ◽

Vol 5 ◽

pp. e3423 ◽

Cited By ~ 18

Author(s):

Ty N.F. Roach ◽

Maria L. Abieri ◽

Emma E. George ◽

Ben Knowles ◽

Douglas S. Naliboff ◽

...

Keyword(s):

Power Output ◽

Energy Use ◽

Human Impacts ◽

Global Scale ◽

Trophic Levels ◽

Maximal Power Output ◽

Bioenergetic Analysis ◽

Lower Oxygen ◽

Thermodynamic Mechanism ◽

Oxygen Concentrations

Human impacts are causing ecosystem phase shifts from coral- to algal-dominated reef systems on a global scale. As these ecosystems undergo transition, there is an increased incidence of coral-macroalgal interactions. Mounting evidence indicates that the outcome of these interaction events is, in part, governed by microbially mediated dynamics. The allocation of available energy through different trophic levels, including the microbial food web, determines the outcome of these interactions and ultimately shapes the benthic community structure. However, little is known about the underlying thermodynamic mechanisms involved in these trophic energy transfers. This study utilizes a novel combination of methods including calorimetry, flow cytometry, and optical oxygen measurements, to provide a bioenergetic analysis of coral-macroalgal interactions in a controlled aquarium setting. We demonstrate that the energetic demands of microbial communities at the coral-algal interaction interface are higher than in the communities associated with either of the macroorganisms alone. This was evident through higher microbial power output (energy use per unit time) and lower oxygen concentrations at interaction zones compared to areas distal from the interface. Increases in microbial power output and lower oxygen concentrations were significantly correlated with the ratio of heterotrophic to autotrophic microbes but not the total microbial abundance. These results suggest that coral-algal interfaces harbor higher proportions of heterotrophic microbes that are optimizing maximal power output, as opposed to yield. This yield to power shift offers a possible thermodynamic mechanism underlying the transition from coral- to algal-dominated reef ecosystems currently being observed worldwide. As changes in the power output of an ecosystem are a significant indicator of the current state of the system, this analysis provides a novel and insightful means to quantify microbial impacts on reef health.

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Context-dependency in biodiversity-multifunctionality relationships is driven by nitrogen availability and plant functional composition

10.1101/2020.08.17.254086 ◽

2020 ◽

Author(s):

Noémie A. Pichon ◽

Seraina L. Cappelli ◽

Santiago Soliveres ◽

Tosca Mannall ◽

Thu Zar Nwe ◽

...

Keyword(s):

Species Richness ◽

Plant Species ◽

Functional Diversity ◽

Experimental Studies ◽

Plant Species Richness ◽

Trophic Levels ◽

Context Dependency ◽

Composition Gradient ◽

Nitrogen Enrichment ◽

Functional Composition

SummaryThe ability of an ecosystem to deliver multiple functions at high levels (multifunctionality) typically increases with biodiversity but there is substantial variation in the strength and direction of biodiversity effects, suggesting context-dependency. However, the drivers of this context dependency have not been identified and understood in comparative meta-analyses or experimental studies. To determine how different factors modulate the effect of diversity on multifunctionality, we conducted a large grassland experiment with 216 communities, crossing a manipulation of plant species richness (1-20 species) with manipulations of resource availability (nitrogen enrichment), plant functional composition (gradient in mean specific leaf area [SLA] to manipulate abundances of fast vs. slow species), plant functional diversity (variance in SLA) and enemy abundance (fungal pathogen removal). We measured ten functions, above and belowground, related to productivity, nutrient cycling and energy transfer between trophic levels, and calculated multifunctionality. Plant species richness and functional diversity both increased multifunctionality, but their effects were context dependent. Species richness increased multifunctionality, but only when communities were assembled with fast growing (high SLA) species. This was because slow species were more redundant in their functional effects, whereas fast species tended to promote different functions. Functional diversity also increased multifunctionality but this effect was dampened by nitrogen enrichment, however, unfertilised, functionally diverse communities still delivered more functions than low diversity, fertilised communities. Our study suggests that a shift towards exploitative communities will not only alter ecosystem functioning but also the strength of biodiversity-functioning relationships, which highlights the potentially complex effects of global change on multifunctionality.

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Gut content analysis of cattle egrets (Bubulcus ibis) in Asam Kumbang Crocodile Park, North Sumatra

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/912/1/012105 ◽

2021 ◽

Vol 912 (1) ◽

pp. 012105

Author(s):

E Jumilawaty ◽

N Namira ◽

A Anggelicha ◽

A Hartanto

Keyword(s):

Content Analysis ◽

Prey Species ◽

Prey Availability ◽

Biological Control Agent ◽

Food Resource ◽

Control Agent ◽

Gut Content Analysis ◽

Gut Content ◽

Dominant Group ◽

Bubulcus Ibis

Abstract Cattle egret (Bubulcus ibis) is a widespread avian species inhabiting a variety of natural and artificial sites. Asam Kumbang Crocodile Park is one of establishments that occupied some portions of B. ibis habitat with no recent information on the food resource and prey availability for the viability of B. ibis. To this aim, we collected 10 random individuals of B. ibis to be sacrificed for gut content analysis of prey species. A total of 19 taxa was found as prey items in the gut of B. ibis with the dominant group from insects (Orthoptera, Scolopendromorpha). The diversity of prey species was categorized as moderate with intraspecific diet variation which formed four guilds that fed on specific taxa namely Group 1 (Haplotaxida, Lepidoptera, Anurans), Group 2 (Blattodea, Coleoptera, Araneae), Group 3 (Orthoptera, Scolopendromorpha); and Group 4 (Dermaptera, Squamata). Oxya chinensis and Oxya velox are important rice grasshopper pests that were also found in the gut of B. ibis reflecting their potential function as biological control agent.

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The freshwater mysid Mysis diluviana (Audzijonyte & Väinölä, 2005) (Mysida: Mysidae) consumes detritus in the presence of Daphnia (Cladocera: Daphniidae)

Journal of Crustacean Biology ◽

10.1093/jcbiol/ruaa053 ◽

2020 ◽

Vol 40 (5) ◽

pp. 520-525

Author(s):

Jessica E Griffin ◽

Brian P O’Malley ◽

Jason D Stockwell

Keyword(s):

Food Resources ◽

Trophic Levels ◽

Arctic Lakes ◽

Mysis Relicta ◽

Combination Treatments ◽

Mysis Diluviana ◽

Benthic Food ◽

Benthic Resources ◽

Trophic Role

Abstract Freshwater mysids of the Mysis relicta group are omnivorous macroinvertebrates that form an important link between fishes and lower trophic levels in many north temperate to Arctic lakes, where they exhibit diel vertical migration (DVM) to exploit subsurface food-rich layers at night. Benthic food resources have been assumed to be less important for mysid diets than pelagic zooplankton. Studies have nevertheless indicated that mysids consume benthic sedimented detritus, calling this assumption into question. We conducted a food-choice experiment to evaluate the feeding preferences of Mysis diluviana (Audzijonyte & Väinölä, 2005) by presenting field-caught specimens in individual foraging arenas with multiple choices of food. Experimental food treatments included a preferred pelagic prey (Daphnia), a presumed less desirable benthic resource (detritus), and a combination of both. We hypothesized that M. diluviana 1) prefers Daphnia over detritus and consumes only Daphnia in combination treatments, and 2) would not consume detritus except when detritus was the only food source available. Contrary to our hypothesis, M. diluviana readily consumed detritus in the presence of Daphnia. Mysis diluviana unexpectedly consumed more individuals of Daphnia in the presence rather than in the absence of detritus. Our results demonstrate that mysids take advantage of benthic food resources even in the presence of a presumably preferred zooplankton prey, calling to question the long-held assumption that benthic resources are unimportant when considering the trophic role of freshwater mysids of the M. relicta group.

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Freshwater Mussels as a Prehistoric Food Resource

American Antiquity ◽

10.2307/279431 ◽

1974 ◽

Vol 39 (3) ◽

pp. 421-434 ◽

Cited By ~ 70

Author(s):

Paul W. Parmalee ◽

Walter E. Klippel

Keyword(s):

Mississippi River ◽

Freshwater Mussels ◽

Food Resource ◽

Food Resources ◽

Archaeological Sites ◽

Eastern North America ◽

Subsistence Economies ◽

Level Data ◽

Food Potential ◽

Prehistoric Subsistence

AbstractThe explication of prehistoric subsistence economies has been of increasing interest to archaeologists. This emphasis is reflected, in part, by the considerable attention afforded faunal analyses in the recent archaeological literature. However, little effort has been made toward developing methods that permit meaningful comparisons of food resources at the interspecies level. Data pertinent to the calculation of both quantitative and qualitative food potential of many of the vertebrate animals represented in archaeological contexts are extant. These data are lacking for freshwater mussels, frequently found in archaeological sites in eastern North America. Information relevant to determining the food energy provided by freshwater mussels common to much of the Mississippi River drainage is presented. Results are applicable to more credible interpretations of prehistoric subsistence as related to animal food resources.

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Aquatic insects as the main food resource of fish the community in a Neotropical reservoir

Neotropical Ichthyology ◽

10.1590/s1679-62252009000400020 ◽

2009 ◽

Vol 7 (4) ◽

pp. 701-708 ◽

Cited By ~ 23

Author(s):

Ana Paula Vidotto-Magnoni ◽

Edmir Daniel Carvalho

Keyword(s):

Aquatic Insects ◽

Food Resource ◽

Gravimetric Method ◽

Stomach Contents ◽

Food Resources ◽

Food Category ◽

Main Food ◽

Tietê River ◽

Two Samples ◽

Terrestrial Insects

We evaluated the feeding of fish species of the Nova Avanhandava Reservoir, low Tietê River, São Paulo State, Brazil. Fishes were collected in two stretches of the reservoir: Santa Bárbara (14 samples) and Bonito (two samples) between September 2002 and March 2004, using gill and seining nets. The results of stomach contents analysis were expressed with the frequency of occurrence and gravimetric method, combined in the Alimentary Index (AI). The 20 species studied consumed 52 food items, grouped in 10 food categories: aquatic insects, terrestrial insects, crustaceans, fish, macroinvertebrates, microcrustaceans, algae, vegetal matter, detritus/sediment and scales. The aquatic insects (mainly Chironomidae, Odonata and Ephemeroptera) were the most common food resources, consumed by 18 species. The diet composition of the community (species grouped) indicated that the dominant food category in the diet of fishes was aquatic insects (AI = 77.6%), followed by crustaceans (AI = 7.1%). Four trophic guilds were identified according a cluster analysis (Pearson distance): insectivorous (10 species), omnivorous (4 species), detritivorous (3 species) and piscivorous/carcinophagous (3 species). Despite the highest number of species, the insectivorous guild was responsible for more than 80% in captures in number and biomass (CPUEn and CPUEb). The low values of niche breadth presented by all species, along with the low values of diet overlap between species pairs indicate a high degree of food resources partitioning among species. The aquatic insects, despite being the main food resource of insectivorous fishes, also complemented the diet of other species, which demonstrate the importance of this food resource for the fish community, sustaining a high diversity, abundance and biomass of fishes.

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