Role of Predatory Fish in Community Dynamics of an Ephemeral Stream

1992 ◽  
Vol 49 (11) ◽  
pp. 2322-2330 ◽  
Author(s):  
Joseph R. Holomuzki ◽  
R. Jan Stevenson
Keyword(s):  
Community Dynamics ◽  
Structural Complexity ◽  
Benthic Algae ◽  
Fish Predation ◽  
Trophic Levels ◽  
Predatory Fish ◽  
Functional Feeding Groups ◽  
Ephemeral Stream ◽  
Surface Exchange ◽  
Invertebrate Predators

In enclosed runs in a third-order ephemeral stream in west-central Kentucky, the effects of predatory sunfish (Lepomis) on benthic macroinvertebrates, benthic algae, and detritivory were compared (1) before stream intermittence, (2) after stream intermittence when transport was restricted, and (3) between substrata offering differential cover from fish predation. Ambient fish densities had little effect on total macrobenthic densities and processes on lower trophic levels before intermittence. Fish modestly affected macroinvertebrate densities after intermittence, when surface exchange of prey was interrupted by sections of dry stream. Among substrata, fish influenced macroinvertebrates on bedrock, but not on stony, coarse substrata. Densities of two taxa were significantly affected by fish, and this significantly altered the relative abundance of functional feeding groups in enclosures on bedrock by increasing the proportion of invertebrate predators in fish treatments. Macroinvertebrate densities in microhabitats on both substrata were not affected by fish presence. Dense growths of the stalked diatom Cymbella generally covered microhabitats and added structural complexity, particularly to bedrock surfaces. Unobstructed, natural migration of prey in the large (40 m2) fencelike enclosures (versus containers), ample refuge space, and low natural densities of fish were important in minimizing fish effects in enclosures.

Periphyton Responses to Higher Trophic Levels and Light in a Shaded Stream

1990 ◽  
Vol 47 (12) ◽  
pp. 2307-2314 ◽  
Author(s):  
Walter R. Hill ◽  
Bret C. Harvey
Keyword(s):  
Primary Productivity ◽  
Light Availability ◽  
Fish Predation ◽  
Trophic Levels ◽  
Predatory Fish ◽  
Light Limitation ◽  
Ambient Light ◽  
Semotilus Atromaculatus ◽  
Highly Correlated ◽  
Elimia Clavaeformis

The effects of higher trophic levels on benthic primary producers were examined in the context of light limitation in a shaded headwater stream. Abundance (presence or absence) of a predatory fish Semotilus atromaculatus and a grazing snail Elimia clavaeformis were manipulated with in situ Plexiglas channels, while spatial variability in ambient light was related to variability in primary productivity among channels. Indirect effects of fish on periphyton were insignificant, possibly because grazers that are vulnerable to fish predation were scarce during the experiment, or because fish preyed upon other predators of grazers. Snails had compensatory effects within the periphyton: they diminished biomass and productivity in the loosely attached layer, but stimulated productivity in the tightly attached layer. Snails appeared to mitigate shading of the tightly attached layer by the loosely attached layer. Benthic primary productivity was highly correlated with ambient light levels, accounting for 42% of the variability in total (loosely and tightly attached layers combined) primary productivity. Multiple regression analysis indicated that fish and snail effects on total primary productivity were minor compared to light effects. These results suggest that light availability controls realized as well as potential production in this unproductive stream.

Trophic Cascades in Grasslands

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.

scholarly journals The importance of species interactions in eco-evolutionary community dynamics under climate change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Anna Åkesson ◽  
Alva Curtsdotter ◽  
Anna Eklöf ◽  
Bo Ebenman ◽  
Jon Norberg ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Community Dynamics ◽  
Evolutionary Dynamics ◽  
Negative Impact ◽  
Trophic Levels ◽  
Temperature Dependent ◽  
Modeling Framework ◽  
Impact Of Climate Change ◽  
The Impact

AbstractEco-evolutionary dynamics are essential in shaping the biological response of communities to ongoing climate change. Here we develop a spatially explicit eco-evolutionary framework which features more detailed species interactions, integrating evolution and dispersal. We include species interactions within and between trophic levels, and additionally, we incorporate the feature that species’ interspecific competition might change due to increasing temperatures and affect the impact of climate change on ecological communities. Our modeling framework captures previously reported ecological responses to climate change, and also reveals two key results. First, interactions between trophic levels as well as temperature-dependent competition within a trophic level mitigate the negative impact of climate change on biodiversity, emphasizing the importance of understanding biotic interactions in shaping climate change impact. Second, our trait-based perspective reveals a strong positive relationship between the within-community variation in preferred temperatures and the capacity to respond to climate change. Temperature-dependent competition consistently results both in higher trait variation and more responsive communities to altered climatic conditions. Our study demonstrates the importance of species interactions in an eco-evolutionary setting, further expanding our knowledge of the interplay between ecological and evolutionary processes.

Effects of juvenile fish predation (Cyprinus carpio L.) on the composition and diversity of free-living freshwater nematode assemblages

Nematology ◽  
2016 ◽  
Vol 18 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Sebastian Weber ◽  
Walter Traunspurger
Keyword(s):  
Species Composition ◽  
Cyprinus Carpio ◽  
Juvenile Fish ◽  
Natural Habitat ◽  
Fish Predation ◽  
Trophic Levels ◽  
Free Living ◽  
Food Web Ecology ◽  
Freshwater Pond ◽  
Predation Effects

Free-living nematodes are well recognised as an abundant and ubiquitous component of meiobenthic communities, where they serve as a link between microbial production and higher trophic levels. However, the effect of fish predation on nematode assemblages is almost unknown. In this study, the predation effects of the benthivorous juvenile carp (Cyprinus carpio) on nematode abundance, biomass, diversity and species composition in the littoral zone of a natural freshwater pond were examined over 310 days using field enclosures and exclosures. Fish predation altered the abundance and biomass of nematodes, and especially of the dominant species Tobrilus gracilis, Eumonhystera filiformis and Monhystera paludicola/stagnalis. Species richness and species composition, but not the diversity and feeding type of nematode assemblages, were affected by fish predation. Our study provides insights into the food-web ecology of lakes and the first evidence of freshwater fish predation effects on nematode assemblages in a natural habitat.

scholarly journals Fish and seagrass communities vary across a marine reserve boundary, but seasonal variation in small fish abundance overshadows top-down effects of large consumer exclosures

2018 ◽  
Author(s):  
James Douglass ◽  
Richard Paperno ◽  
Eric A. Reyier ◽  
Anson H. Hines
Keyword(s):  
Seasonal Variation ◽  
Trophic Levels ◽  
Fish Abundance ◽  
Predatory Fish ◽  
Gut Contents ◽  
Spatial And Temporal Variation ◽  
Small Fish ◽  
Ecosystem Structure ◽  
Top Down ◽  
Exclusion Experiment

A growing number of examples indicate that large predators can alter seagrass ecosystem structure and processes via top-down trophic interactions. However, the nature and strength of those interactions varies with biogeographic context, emphasizing the need for region-specific investigations. We investigated spatial and temporal variation in predatory fish and seagrass communities across a Marine Protected Area (MPA) boundary in the Banana River Lagoon, Florida (USA), assessing trophic roles of intermediate consumers, and performing a large-consumer exclusion experiment in the MPA. Large, predatory fishes were most abundant within the MPA, while some mid-sized fishes were more abundant outside it. Small, seagrass-resident fishes, epifaunal invertebrates, and macrophytes also differed across the MPA boundary, but varied more among individual sites and seasonally. We cannot conclusively attribute these patterns to MPA status because we lack data from prior to MPA establishment and lack study replication at the level of MPA. Nevertheless, other patterns among our data are consistent with hypothesized mechanisms of top-down control. E.g., inverse seasonal patterns in the abundance of organisms at adjacent trophic levels, coupled with stable C and N isotope and gut contents data, suggest top-down control of crustacean grazers by seasonal recruitment of small fishes. Large-consumer exclosures in the MPA increased the abundance of mid-sized predatory and omnivorous fishes, but had few impacts on lower trophic levels. Results suggest that large-scale variation in large, predatory fish abundance in this system does not strongly affect seagrass-resident fish, invertebrate, and algal communities, which appear to be driven more by habitat structure and seasonal variation in small fish abundance.

scholarly journals The rise of the three-spined stickleback – eco-evolutionary consequences of a mesopredator release

2020 ◽  
Author(s):  
Britas Klemens Eriksson ◽  
Casey Yanos ◽  
Sarah Bourlat ◽  
Serena Donadi ◽  
Michael C. Fontaine ◽  
...  
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Stomach Content ◽  
Ecological Effects ◽  
Trophic Levels ◽  
Predatory Fish ◽  
Series Data ◽  
Food Web Structure ◽  
Benthic Production ◽  
Invertebrate Herbivores

AbstractDeclines of large predatory fish due to overexploitation are restructuring food webs across the globe. It is now becoming evident that restoring these altered food webs requires addressing not only ecological processes, but evolutionary ones as well, because human-induced rapid evolution may in turn affect ecological dynamics. In the central Baltic Sea, abundances of the mesopredatory fish, the three-spined stickleback (Gasterosteus aculeatus), have increased dramatically during the past decades. Time-series data covering 22 years show that this increase coincides with a decline in the number of juvenile perch (Perca fluviatilis), the most abundant predator of stickleback along the coast. We studied the interaction between evolutionary and ecological effects of this mesopredator take-over, by surveying the armour plate morphology of stickleback and the structure of the associated food web. First, we investigated the distribution of different stickleback phenotypes depending on predator abundances and benthic production; and described the stomach content of the stickleback phenotypes using metabarcoding. Second, we explored differences in the relation between different trophic levels and benthic production, between bays where the relative abundance of fish was dominated by stickleback or not; and compared this to previous cage-experiments to support causality of detected correlations. We found two distinct lateral armour plate phenotypes of stickleback, incompletely and completely plated. The proportion of incompletely plated individuals increased with increasing benthic production and decreasing abundances of adult perch. Stomach content analyses showed that the completely plated individuals had a stronger preference for invertebrate herbivores (amphipods) than the incompletely plated ones. In addition, predator dominance interacted with ecosystem production to determine food web structure and the propagation of a trophic cascade: with increasing production, biomass accumulated on the first (macroalgae) and third (stickleback) trophic levels in stickleback-dominated bays, but on the second trophic level (invertebrate herbivores) in perch-dominated bays. Since armour plates are defence structures favoured by natural selection in the presence of fish predators, the phenotype distribution suggest that a novel low-predation regime favours sticklebacks with less armour. Our results indicate that an interaction between evolutionary and ecological effects of the stickleback take-over has the potential to affect food web dynamics.

A study of food chains in seagrass communities. III. Stable carbon isotope ratios

1985 ◽  
Vol 36 (5) ◽  
pp. 683 ◽  
Author(s):  
PD Nichols ◽  
DW Klumpp ◽  
RB Johns
Keyword(s):  
Carbon Isotope ◽  
Opposite Effect ◽  
Stable Carbon Isotope ◽  
Benthic Algae ◽  
Trophic Levels ◽  
Food Chains ◽  
Stable Carbon ◽  
Commercial Fish ◽  
Δ13c Values ◽  
Stable Carbon Isotope Ratios

Stable carbon isotope determinations have been used to obtain a general background to food chains being studied by a range of chemical and biological techniques. δ13C values indicate that animals (δ13CC - 11.4‰ to - 14.9‰), including two locally important commercial fish, Platycephalus laevigatus (rock flathead) and Hyporhamphus melanochir (southern sea garfish), from the Corner Inlet seagrass and non-seagrass communities are dependent to varying degrees upon seagrass (δ13C - 7.0‰ to - 9.3‰) and benthic algae for their carbon source. The largest changes in δ13C values in the food chains is at the point involving seagrasses and their direct herbivores. The latter have more negative δ13C values (H. melanochir - 12.1%o, isopods - 11.4%o). Little or no change in δ13C values is apparent at the higher trophic levels (carnivores - 13 .0‰ to - 14.9‰). Epiphytic material on the fresh leaves of the two seagrass species in the Inlet is depleted in 13C when compared with the seagrass leaves. An opposite effect is observed for epiphytic material on Posidonia australis detritus.

Fisheries

2007 ◽  
Author(s):  
John R. Beddington ◽  
Geoffrey P. Kirkwood
Keyword(s):  
Trophic Level ◽  
Global Scale ◽  
Trophic Levels ◽  
Predatory Fish ◽  
Apex Predators ◽  
The North ◽  
The Mean ◽  
Mean Trophic Level ◽  
Global Statistics ◽  
United Nations Food

The depletion of fish stocks on a global scale is well documented. The United Nations Food and Agriculture Organisation collects statistics on fisheries from all states and, despite obvious shortcomings in the data, a clear picture has been available for some time. Garcia and Grainger (2005) have succinctly documented the position from the latest available date: in 2003, only 3% of stocks were underexploited and 26% moderately exploited, while 52% were fully exploited, 16% were overfished, 7% were depleted, and 1% were recovering from earlier depletion. These global statistics mask two important phenomena. The first, highlighted by Pauly et al. (1998), is that fisheries are increasingly focusing on species lower down in the food-web and the second, highlighted by Myers and Worm (2003, 2005), is that large predatory fish have been particularly reduced in abundance. Both of these analyses are somewhat flawed. In the case of Pauly et al. there are two problems: the first is that the metrics used for the mean trophic level are presented as simple numbers with no estimates of error or indeed sensitivity. In such a situation, the changes in mean trophic levels are hard to interpret, particularly where the mean trophic level changes by at most around 10% over four decades. The second problem has been highlighted by a recent paper by Essington et al. (2006). They point out that in the periods when according to the analysis of Pauly et al. the mean trophic level was declining, in most cases catches of apex predators and indeed all upper trophic levels increased (an exception is the North Atlantic). In the case of the Myers and Worm analysis, they used the catch per unit of effort (CPUE) as an index of abundance. As discussed later in this chapter, there are problems with this, but more importantly for some key apex predators, in particular large tunas, the CPUE declines in the early stages of the fishery, where catches are small, but remains relatively stable under a regime of much higher catches. In such a situation, the interpretation that the CPUE reflects changes in abundance is clearly problematic.

Does the river continuum concept apply on a tropical island? Longitudinal variation in a Puerto Rican stream

2006 ◽  
Vol 63 (1) ◽  
pp. 134-152 ◽  
Author(s):  
Effie A Greathouse ◽  
Catherine M Pringle
Keyword(s):  
Puerto Rico ◽  
Fish Predation ◽  
Functional Feeding Groups ◽  
River Continuum Concept ◽  
Running Waters ◽  
River Continuum ◽  
Feeding Mode ◽  
Continuum Concept ◽  
Basal Resources ◽  
Stream Size

We examined whether a tropical stream in Puerto Rico matched predictions of the river continuum concept (RCC) for macroinvertebrate functional feeding groups (FFGs). Sampling sites for macroinvertebrates, basal resources, and fishes ranged from headwaters to within 2.5 km of the fourth-order estuary. In a comparison with a model temperate system in which RCC predictions generally held, we used catchment area as a measure of stream size to examine truncated RCC predictions (i.e., cut off to correspond to the largest stream size sampled in Puerto Rico). Despite dominance of generalist freshwater shrimps, which use more than one feeding mode, RCC predictions held for scrapers, shredders, and predators. Collector–filterers showed a trend opposite to that predicted by the RCC, but patterns in basal resources suggest that this is consistent with the central RCC theme: longitudinal distributions of FFGs follow longitudinal patterns in basal resources. Alternatively, the filterer pattern may be explained by fish predation affecting distributions of filter-feeding shrimp. Our results indicate that the RCC generally applies to running waters on tropical islands. However, additional theoretical and field studies across a broad array of stream types should examine whether the RCC needs to be refined to reflect the potential influence of top-down trophic controls on FFG distributions.

δ15N in riverine food webs: effects of N inputs from agricultural watersheds

2005 ◽  
Vol 62 (2) ◽  
pp. 333-340 ◽  
Author(s):  
Caroline Anderson ◽  
Gilbert Cabana
Keyword(s):  
Food Webs ◽  
Agricultural Land ◽  
Trophic Levels ◽  
Functional Feeding Groups ◽  
Agricultural Watersheds ◽  
Watershed Scale ◽  
Nitrogen Stable Isotopes ◽  
Piscivorous Fish ◽  
Primary Consumers ◽  
Positive Correlations

We examined the use of the natural abundance of nitrogen stable isotopes (δ15N) as a tracer of anthropo genic perturbations of the nitrogen (N) cycle at the watershed scale in 82 river sites draining 13 watersheds in the St. Lawrence Lowlands in Quebec. Mean δ15N values of aquatic primary consumers varied greatly among sites (+2‰ to +15‰), most of this variation (88%) being attributable to site effects. Variation in δ15N values among functional feeding groups of primary consumers within sites was comparatively lower (<1‰). Within watersheds, δ15N values of primary consumers (and organisms of higher trophic levels) tracked longitudinal changes in the percentage of agricultural area. Overall, the percentage of total watershed area under agriculture explained up to 69% of the variation in mean primary consumer δ15N values. Similar positive correlations were observed for predatory invertebrates and non-piscivorous fish. In general, our results show that δ15N in riverine food webs reacts strongly to spatial patterns in the intensity of N inputs related to agricultural land use.

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