scholarly journals A novel approach to quantifying trophic interaction strengths and impact of invasive species in food webs

2021 ◽  
Author(s):  
Edoardo Calizza ◽  
Loreto Rossi ◽  
Giulio Careddu ◽  
Simona Sporta Caputi ◽  
Maria Letizia Costantini
Keyword(s):  
Invasive Species ◽  
Food Web ◽  
Food Webs ◽  
Fish Species ◽  
Trophic Interaction ◽  
Coregonus Lavaretus ◽  
Commercial Fish ◽  
Novel Approach ◽  
Allochthonous Species ◽  
The Impact

AbstractMeasuring ecological and economic impacts of invasive species is necessary for managing invaded food webs. Based on abundance, biomass and diet data of autochthonous and allochthonous fish species, we proposed a novel approach to quantifying trophic interaction strengths in terms of number of individuals and biomass that each species subtract to the others in the food web. This allowed to estimate the economic loss associated to the impact of an invasive species on commercial fish stocks, as well as the resilience of invaded food webs to further perturbations. As case study, we measured the impact of the invasive bass Micropterus salmoides in two lake communities differing in food web complexity and species richness, as well as the biotic resistance of autochthonous and allochthonous fish species against the invader. Resistance to the invader was higher, while its ecological and economic impact was lower, in the more complex and species-rich food web. The percid Perca fluviatilis and the whitefish Coregonus lavaretus were the two species that most limited the invader, representing meaningful targets for conservation biological control strategies. In both food webs, the limiting effect of allochthonous species against M. salmoides was higher than the effect of autochthonous ones. Simulations predicted that the eradication of the invader would increase food web resilience, while that an increase in fish diversity would preserve resilience also at high abundances of M. salmoides. Our results support the conservation of biodiverse food webs as a way to mitigate the impact of bass invasion in lake ecosystems. Notably, the proposed approach could be applied to any habitat and animal species whenever biomass and diet data can be obtained.

scholarly journals Invasion in An Omnivorous Food Web: The Impact of Roles and Different Trophic Levels

2021 ◽  
Author(s):  
Duojie Jiabu ◽  
Weide Li
Keyword(s):  
Invasive Species ◽  
Food Web ◽  
Food Webs ◽  
Habitat Loss ◽  
Habitat Destruction ◽  
Trophic Levels ◽  
Theoretical Research ◽  
Model Framework ◽  
Habitat Loss And Fragmentation ◽  
The Impact

Abstract In the field of ecology, habitat loss and fragmentation are the two main characteristic forms of habitat destruction and the main drivers of species extinction, resulting in the gradual loss of biodiversity. So far, many scholars have made some progress in the theoretical research of the spatial food web, but research on the effect of introducing an invasive species in an omnivorous food web is very rare. In order to explore the impact of invader on the persistence of species in omnivorous food webs, we constructed a model framework to describe the patch occupation of each species in omnivorous systems. Our model results show that invasive species is a prey of species in omnivorous food webs is easier to invade than invasive species is a predator of species in original omnivorous food webs on habitat loss and fragmentation. One conclusion also can be drawn is that when an invasive species is a prey of species in omnivorous food webs, no matter what trophic level the invasive species is invade, it is more successful. But when invasive species is a predator of species in different trophic levels on omnivorous food webs, they show different coexistence patterns. The invasion of a species has little effect upon the stability of original omnivorous food web for habitat loss and fragmentation, and will only make the original omnivorous food web more stable and more complicated. Therefore, we have proved that the omnivorous food web is stable and is not easy to destroy this ecological fact. Some examples to illustrate the reliability of our model results are discussed.

scholarly journals Mapping and Assessing Commercial Fisheries Services in the Lithuanian Part of the Curonian Lagoon

Fishes ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 19
Author(s):  
Edgaras Ivanauskas ◽  
Andrius Skersonas ◽  
Vaidotas Andrašūnas ◽  
Soukaina Elyaagoubi ◽  
Artūras Razinkovas-Baziukas
Keyword(s):  
Spatial Distribution ◽  
Residence Time ◽  
Fish Species ◽  
Circulation Model ◽  
Curonian Lagoon ◽  
Water Residence Time ◽  
Total Catch ◽  
Catch Per Unit Effort ◽  
Commercial Fish ◽  
The Impact

The spatial distribution of biomass of main commercial fish species was mapped to estimate the supply of a provisioning fishery service in the Curonian lagoon. Catch per unit effort (CPUE) was used as a proxy to estimate the efficiency of commercial fishing and, subsequently, the potential biomass of fishes. The relationship between distinctive characteristics of the fishing areas and corresponding commercial catches and CPUE was analyzed using multivariate analysis. The total catch values and CPUE used in the analyses were derived from the official commercial fishery records. RDE analysis was used to assess the variation of both catch and CPUE of commercial fish species, while the percentages of bottom sediment type coverage, average depth, annual salinity, and water residence time in each of the fishing squares were used as explanatory variables. This distance e-based redundancy analysis allowed for the use of non-Euclidean dissimilarity indices. Fisheries data spatial distribution map indicated the lack of coherence between the spatial patterns of commercial catches and CPUE distribution in the northern part of the lagoon. Highest CPUE values were estimated in the central-eastern part of the lagoon as compared to the western part of the lagoon where CPUE values were substantially lower. Both total catch and CPUE appeared not to be related to the type of bottom habitats statistically while being spatially correlated in-between. However, the impact of salinity and water residence time calculated using the 3D hydraulic circulation model on the distribution of both CPUE and commercial catches was statistically significant.

scholarly journals Untangling the roles of parasites in food webs with generative network models

2015 ◽  
Author(s):  
Abigail Z. Jacobs ◽  
Jennifer A. Dunne ◽  
Cristopher Moore ◽  
Aaron Clauset
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Statistical Physics ◽  
Network Models ◽  
Food Web Structure ◽  
Free Living ◽  
Web Structure ◽  
Living Species ◽  
Parasitic Interactions ◽  
The Impact

Food webs represent the set of consumer-resource interactions among a set of species that co-occur in a habitat, but most food web studies have omitted parasites and their interactions. Recent studies have provided conflicting evidence on whether including parasites changes food web structure, with some suggesting that parasitic interactions are structurally distinct from those among free-living species while others claim the opposite. Here, we describe a principled method for understanding food web structure that combines an efficient optimization algorithm from statistical physics called parallel tempering with a probabilistic generalization of the empirically well-supported food web niche model. This generative model approach allows us to rigorously estimate the degree to which interactions that involve parasites are statistically distinguishable from interactions among free-living species, whether parasite niches behave similarly to free-living niches, and the degree to which existing hypotheses about food web structure are naturally recovered. We apply this method to the well-studied Flensburg Fjord food web and show that while predation on parasites, concomitant predation of parasites, and parasitic intraguild trophic interactions are largely indistinguishable from free-living predation interactions, parasite-host interactions are different. These results provide a powerful new tool for evaluating the impact of classes of species and interactions on food web structure to shed new light on the roles of parasites in food webs.

scholarly journals Regime shifts in marine communities: a complex systems perspective on food web dynamics

2016 ◽  
Vol 283 (1825) ◽  
pp. 20152569 ◽  
Author(s):  
Johanna Yletyinen ◽  
Örjan Bodin ◽  
Benjamin Weigel ◽  
Marie C. Nordström ◽  
Erik Bonsdorff ◽  
...  
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Regime Shift ◽  
Relative Strength ◽  
Regime Shifts ◽  
Exponential Random Graph ◽  
Novel Approach ◽  
Before And After ◽  
Dynamic Perspective ◽  
The Baltic

Species composition and habitats are changing at unprecedented rates in the world's oceans, potentially causing entire food webs to shift to structurally and functionally different regimes. Despite the severity of these regime shifts, elucidating the precise nature of their underlying processes has remained difficult. We address this challenge with a new analytic approach to detect and assess the relative strength of different driving processes in food webs. Our study draws on complexity theory, and integrates the network-centric exponential random graph modelling (ERGM) framework developed within the social sciences with community ecology. In contrast to previous research, this approach makes clear assumptions of direction of causality and accommodates a dynamic perspective on the emergence of food webs. We apply our approach to analysing food webs of the Baltic Sea before and after a previously reported regime shift. Our results show that the dominant food web processes have remained largely the same, although we detect changes in their magnitudes. The results indicate that the reported regime shift may not be a system-wide shift, but instead involve a limited number of species. Our study emphasizes the importance of community-wide analysis on marine regime shifts and introduces a novel approach to examine food webs.

Biological Effects of Oil Pollution

1982 ◽  
Vol 14 (9-11) ◽  
pp. 1185-1194 ◽  
Author(s):  
R B Clark
Keyword(s):  
Fish Species ◽  
Deleterious Effect ◽  
Oil Pollution ◽  
Biological Effects ◽  
Detectable Effect ◽  
Commercial Catch ◽  
Commercial Fish ◽  
The Impact ◽  
Biological Context ◽  
Heavy Mortality

Pollution is defined as environmental contamination which has a deleterious effect, and in a biological context it is only mortality which has some impact at the level of the population or community that is important. Thus, very heavy mortality of the eggs and fry of commercial fish species may have no detectable effect on the commercial catch in future years. A reduction in the population of a species which is dominant in its community, on the other hand is likely to result in major ecological adjustment. Oil pollution does not appear to have reduced populations of commercial fish species or seabirds, the two groups of animals about which most fears have been expressed. The marine environment is subject to wide and erratic fluctuations which make it difficult to detect the impact of oil pollution unless the cause is obvious, even then some caution is necessary before attributing environmental change to pollution.

scholarly journals Mercury source changes and food web shifts alter contamination signatures of predatory fish from Lake Michigan

2019 ◽  
Vol 116 (47) ◽  
pp. 23600-23608 ◽  
Author(s):  
Ryan F. Lepak ◽  
Joel C. Hoffman ◽  
Sarah E. Janssen ◽  
David P. Krabbenhoft ◽  
Jacob M. Ogorek ◽  
...  
Keyword(s):  
Invasive Species ◽  
Great Lakes ◽  
Food Web ◽  
Lake Michigan ◽  
Lake Trout ◽  
Mitigation Strategies ◽  
Predatory Fish ◽  
Isotopic Analyses ◽  
C And N ◽  
The Impact

To understand the impact reduced mercury (Hg) loading and invasive species have had on methylmercury bioaccumulation in predator fish of Lake Michigan, we reconstructed bioaccumulation trends from a fish archive (1978 to 2012). By measuring fish Hg stable isotope ratios, we related temporal changes in Hg concentrations to varying Hg sources. Additionally, dietary tracers were necessary to identify food web influences. Through combined Hg, C, and N stable isotopic analyses, we were able to differentiate between a shift in Hg sources to fish and periods when energetic transitions (from dreissenid mussels) led to the assimilation of contrasting Hg pools (2000 to present). In the late 1980s, lake trout δ202Hg increased (0.4‰) from regulatory reductions in regional Hg emissions. After 2000, C and N isotopes ratios revealed altered food web pathways, resulting in a benthic energetic shift and changes to Hg bioaccumulation. Continued increases in δ202Hg indicate fish are responding to several United States mercury emission mitigation strategies that were initiated circa 1990 and continued through the 2011 promulgation of the Mercury and Air Toxics Standards rule. Unlike archives of sediments, this fish archive tracks Hg sources susceptible to bioaccumulation in Great Lakes fisheries. Analysis reveals that trends in fish Hg concentrations can be substantially affected by shifts in trophic structure and dietary preferences initiated by invasive species in the Great Lakes. This does not diminish the benefits of declining emissions over this period, as fish Hg concentrations would have been higher without these actions.

Nutrient inputs versus piscivore biomass as the primary driver of reservoir food webs

2013 ◽  
Vol 70 (3) ◽  
pp. 367-380 ◽  
Author(s):  
Bryan T. Kinter ◽  
Stuart A. Ludsin
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Striped Bass ◽  
Gizzard Shad ◽  
Hybrid Striped Bass ◽  
Top Predator ◽  
Nutrient Inputs ◽  
Food Web Structure ◽  
Introduced Predators ◽  
The Impact

We used an ecosystem-based modeling approach, Ecopath with Ecosim, to explore the relative importance of a top-down biotic management lever (top predator introduction) versus a bottom-up abiotic management lever (alteration of nutrient inputs) in regulating biomass in reservoir food webs. To do so, we modeled three Ohio reservoirs that varied in ecosystem productivity. For each, we simulated five hybrid striped bass (Morone chrysops × Morone saxatilis) (introduced top predator) biomass levels at three nutrient input levels (n = 15 simulations per reservoir). Nutrient inputs influenced the food web more than introduced predators within each reservoir. Further, across all three reservoirs, the impact of stocked hybrid striped bass on the equilibrium biomass of phytoplankton, prey fish (gizzard shad, Dorosoma cepedianum), and native top predators (e.g., largemouth bass, Micropterus salmoides) was <3%, <14%, and <20%, respectively, of the maximum impact of changes in nutrient inputs on these components. Thus, in mesotrophic to hypereutrophic reservoirs that are dominated by omnivorous gizzard shad, manipulating allochthonous inputs of nutrients offers agencies a more powerful means to regulate food web structure than manipulation of top predator biomass.

scholarly journals Comparative assessment of amateur fishing influence on water bioresources of Lake Tsatsa in Volgograd region

2021 ◽  
Vol 0 (4) ◽  
pp. 57-62
Author(s):  
Nikolai Vladimirovich Kutsenko ◽  
Yulia Nikolaevna Grozesku ◽  
Anton Alexeyevich Filipenko
Keyword(s):  
Fish Species ◽  
Field Studies ◽  
Quantitative Composition ◽  
Production Volume ◽  
Total Allowable Catch ◽  
Commercial Fish ◽  
Volgograd Region ◽  
The Impact ◽  
Total Stock ◽  
Observation Period

The paper presents the results of research conducted in 2020 on the impact of amateur fishing on the aquatic bioresources of Lake Tsatsa, which is part of the Sarpin Lakes located in the Volgograd region. On the basis of field studies (direct accounting), the number of amateur fishermen who visited the lake, as well as the qualitative and quantitative composition of their catches, was established. According to the data obtained, the total catch of fish by amateur fishermen, as well as the average catch per fisherman, was estimated. The size and weight composition of amateur fishing catches was determined based on the analysis of 2912 fish species. During the observation period 9 fish species were marked as part of amateur fishermen’s catches. The assessment of compliance of aquatic biological resources catch by amateur fishermen with the norms of the current Fishing Regulations was carried out. An assessment of the scale of amateur fishing impact on the aquatic bioresources of Lake Tsatsa is given, according to the analysis of the collected data. The catch of amateur fishermen in 2020 in Lake Tsatsa is amounted to 8.8232 tons, which can account for up to 15% (about 65-70 tons) of the total stock of commercial fish species in the lake. The forecast values of the production volume for industrial fisheries, for which the total allowable catch (TAC) is established and the species for which the recommended catch is determined, are 5.9 and 18.6 tons, respectively. Out of the forecast volumes amateur fishermen additionally catch fish species for which the total allowable catch (TAC) is established (carp, bream, pike) in the amount of 2.858 tons, and species for which the recommended catch value is determined as 5.643 tons.

scholarly journals Seasonal food webs with migrations: multi-season models reveal indirect species interactions in the Canadian Arctic tundra

2020 ◽  
Vol 378 (2181) ◽  
pp. 20190354 ◽  
Author(s):  
Chantal Hutchison ◽  
Frédéric Guichard ◽  
Pierre Legagneux ◽  
Gilles Gauthier ◽  
Joël Bêty ◽  
...  
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Ecosystem Functioning ◽  
Species Interactions ◽  
Multiple Equilibria ◽  
Community Dynamics ◽  
Static Model ◽  
Predator Prey ◽  
Summer Time ◽  
The Impact

Models incorporating seasonality are necessary to fully assess the impact of global warming on Arctic communities. Seasonal migrations are a key component of Arctic food webs that still elude current theories predicting a single community equilibrium. We develop a multi-season model of predator–prey dynamics using a hybrid dynamical systems framework applied to a simplified tundra food web (lemming–fox–goose–owl). Hybrid systems models can accommodate multiple equilibria, which is a basic requirement for modelling food webs whose topology changes with season. We demonstrate that our model can generate multi-annual cycling in lemming dynamics, solely from a combined effect of seasonality and state-dependent behaviour. We compare our multi-season model to a static model of the predator–prey community dynamics and study the interactions between species. Interestingly, including seasonality reveals indirect interactions between migrants and residents not captured by the static model. Further, we find that the direction and magnitude of interactions between two species are not necessarily accurate using only summer time-series. Our study demonstrates the need for the development of multi-season models and provides the tools to analyse them. Integrating seasonality in food web modelling is a vital step to improve predictions about the impacts of climate change on ecosystem functioning. This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning’.

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