Combining scientific and fishers’ knowledge to co-create indicators of food web structure and function

2019 ◽  
Author(s):  
Jacob W Bentley ◽  
David E Hines ◽  
Stuart R Borrett ◽  
Natalia Serpetti ◽  
Gema Hernandez-Milian ◽  
...  
Keyword(s):  
Food Web ◽  
Integrated Management ◽  
Irish Sea ◽  
Food Web Structure ◽  
Predator Prey ◽  
Before And After ◽  
Commercial Species ◽  
Ecosystem Level ◽  
The Irish Sea ◽  
And Function

Abstract In this study, we describe the approach taken by the International Council for the Exploration of the Seas Irish Sea benchmark working group (WKIrish), to co-create diet information for six commercial species using fishers' and scientists knowledge and incorporate it into an existing Ecopath food web model of the Irish Sea. To understand how the co-created diet information changed the model we compared a suite of food web indicators before and after the addition of fishers' knowledge (FK). Of the 80 predator–prey interactions suggested by fishers during workshops, 50 were already included in the model. Although the small number of changes made to the model structure had an insignificant impact on the ecosystem-level indicators, indicators of species hierarchical importance and mixed trophic impacts were significantly changed, particularly for commercial species. FK heightened the importance of discards as a source of food for rays, plaice, and whiting and reduced the importance of cod, toothed whales, and plaice as structural components of the food web. FK therefore led to changes which will influence pairwise advice derived from the model. We conclude by providing lessons from WKIrish which we believe were key to the positive co-production experience and development of integrated management.

scholarly journals Seasonal Food Web Dynamics in the Antarctic Benthos of Tethys Bay (Ross Sea): Implications for Biodiversity Persistence Under Different Seasonal Sea-Ice Coverage

2020 ◽  
Vol 7 ◽  
Author(s):  
Simona Sporta Caputi ◽  
Giulio Careddu ◽  
Edoardo Calizza ◽  
Federico Fiorentino ◽  
Deborah Maccapan ◽  
...  
Keyword(s):  
Sea Ice ◽  
Food Web ◽  
Ross Sea ◽  
Food Web Structure ◽  
Ice Dynamics ◽  
Web Architecture ◽  
Sea Ice Dynamics ◽  
Before And After ◽  
Basal Resources ◽  
Break Up

Determining food web architecture and its seasonal cycles is a precondition for making predictions about Antarctic marine biodiversity under varying climate change scenarios. However, few scientific data concerning Antarctic food web structure, the species playing key roles in web stability and the community responses to changes in sea-ice dynamics are available. Based on C and N stable isotope analysis, we describe Antarctic benthic food webs and the diet of species occurring in shallow waters (Tethys Bay, Ross Sea) before and after seasonal sea-ice break-up. We hypothesized that the increased availability of primary producers (sympagic algae) following sea-ice break-up affects the diet of species and thus food web architecture. Basal resources had distinct isotopic signatures that did not change after sea-ice break-up, enabling a robust description of consumer diets based on Bayesian mixing models. Sympagic algae had the highest δ13C (∼−14‰) and red macroalgae the lowest (∼−37‰). Consumer isotopic niches and signatures changed after sea-ice break-up, reflecting the values of sympagic algae. Differences in food web topology were also observed. The number of taxa and the number of links per taxon were higher before the thaw than after it. After sea-ice break-up, sympagic inputs allowed consumers to specialize on abundant resources at lower trophic levels. Foraging optimization by consumers led to a simpler food web, with lower potential competition and shorter food chains. However, basal resources and Antarctic species such as the bivalve Adamussium colbecki and the sea-urchin Sterechinus neumayeri were central and highly connected both before and after the sea-ice break-up, thus playing key roles in interconnecting species and compartments in the web. Any disturbance affecting these species is expected to have cascading effects on the entire food web. The seasonal break-up of sea ice in Antarctica ensures the availability of resources that are limiting for coastal communities for the rest of the year. Identification of species playing a key role in regulating food web structure in relation to seasonal sea-ice dynamics, which are expected to change with global warming, is central to understanding how these communities will respond to climate change.

Predator kairomones change food web structure and function, regardless of cues from consumed prey

Oikos ◽  
2015 ◽  
Vol 125 (7) ◽  
pp. 1017-1026 ◽  
Author(s):  
Nicholas A. C. Marino ◽  
Diane S. Srivastava ◽  
Vinicius F. Farjalla
Keyword(s):  
Food Web ◽  
Structure And Function ◽  
Food Web Structure ◽  
Web Structure ◽  
And Function

Biochemical polymorphism in bass, Dicentrarchus labrax, in the waters around the British Isles

1992 ◽  
Vol 72 (2) ◽  
pp. 357-364 ◽  
Author(s):  
A.R. Child
Keyword(s):  
Dicentrarchus Labrax ◽  
Irish Sea ◽  
Detailed Knowledge ◽  
British Isles ◽  
Stock Management ◽  
Eastern Atlantic Ocean ◽  
Commercial Species ◽  
The Irish Sea ◽  
Southern Norway ◽  
The Uk

The bass Dicentrarchus labrax is found in the eastern Atlantic Ocean from Morocco (30°N) to southern Norway (60°N) and in the Mediterranean and Black Seas (Whitehead et al., 1986). Throughout its range the bass is an important commercial species and in the waters around the British Isles it is exploited both by commercial fishermen and by sport anglers.Since the early 1970s the recorded landings of bass have increased considerably (Pickett & Pawson, 1991). The increased exploitation and the conflict of interest between sport fishermen and commercial bass fishermen have been the subject of a multitude of articles in the fishing press calling for greater stock management. Detailed knowledge of the stock structure was required to provide advice on the management of the UK bass fishery (Pawson & Pickett, 1987).Prior to 1980, tagging studies were conducted off the southern coast of Ireland (Kennedy & Fitzmaurice, 1972), the south-west of England (Holden & Williams, 1974) and in the Irish Sea (Kelley, 1979).

scholarly journals Size-dependent functional response of Xenopus laevis feeding on mosquito larvae

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5813 ◽  
Author(s):  
Corey J. Thorp ◽  
Mhairi E. Alexander ◽  
James R. Vonesh ◽  
John Measey
Keyword(s):  
Xenopus Laevis ◽  
Functional Response ◽  
Handling Time ◽  
Mosquito Larvae ◽  
Agricultural Pests ◽  
Food Web Structure ◽  
Predator Prey ◽  
Predator Attack ◽  
Considerable Individual Variation ◽  
And Function

Predators can play an important role in regulating prey abundance and diversity, determining food web structure and function, and contributing to important ecosystem services, including the regulation of agricultural pests and disease vectors. Thus, the ability to predict predator impact on prey is an important goal in ecology. Often, predators of the same species are assumed to be functionally equivalent, despite considerable individual variation in predator traits known to be important for shaping predator–prey interactions, like body size. This assumption may greatly oversimplify our understanding of within-species functional diversity and undermine our ability to predict predator effects on prey. Here, we examine the degree to which predator–prey interactions are functionally homogenous across a natural range of predator body sizes. Specifically, we quantify the size-dependence of the functional response of African clawed frogs (Xenopus laevis) preying on mosquito larvae (Culex pipiens). Three size classes of predators, small (15–30 mm snout-vent length), medium (50–60 mm) and large (105–120 mm), were presented with five densities of prey to determine functional response type and to estimate search efficiency and handling time parameters generated from the models. The results of mesocosm experiments showed that type of functional response of X. laevis changed with size: small predators exhibited a Type II response, while medium and large predators exhibited Type III responses. Functional response data showed an inversely proportional relationship between predator attack rate and predator size. Small and medium predators had highest and lowest handling time, respectively. The change in functional response with the size of predator suggests that predators with overlapping cohorts may have a dynamic impact on prey populations. Therefore, predicting the functional response of a single size-matched predator in an experiment may misrepresent the predator’s potential impact on a prey population.

scholarly journals Southern Ocean Food Web Modelling: Progress, Prognoses, and Future Priorities for Research and Policy Makers

2021 ◽  
Vol 9 ◽  
Author(s):  
Stacey A. McCormack ◽  
Jessica Melbourne-Thomas ◽  
Rowan Trebilco ◽  
Gary Griffith ◽  
Simeon L. Hill ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Food Web ◽  
Alternative Energy ◽  
Food Web Structure ◽  
Policy Makers ◽  
Web Structure ◽  
Pelagic Food Webs ◽  
Graphical Summary ◽  
And Function ◽  
Research And Policy

Graphical AbstractGraphical summary of multiple aspects of Southern Ocean food web structure and function including alternative energy pathways through pelagic food webs, climate change and fisheries impacts and the importance of microbial networks and benthic systems.

Large-scale responses of nematode communities to chronic otter-trawl disturbance

2008 ◽  
Vol 65 (4) ◽  
pp. 723-732 ◽  
Author(s):  
Hilmar Hinz ◽  
Jan G Hiddink ◽  
James Forde ◽  
Michel J Kaiser
Keyword(s):  
Food Web ◽  
North Sea ◽  
Large Scale ◽  
Life Cycles ◽  
Irish Sea ◽  
Otter Trawl ◽  
Food Web Structure ◽  
Nematode Communities ◽  
The North ◽  
The North Sea

Nematodes, because of their small size and short life cycles, are thought to be less affected by direct trawling mortality compared with the larger macrofauna. However, nematodes may still be indirectly affected by the physical disturbance of trawling through changing sediment characteristics and food web structure. We determined whether nematode communities on two muddy fishing grounds located in the North Sea and Irish Sea were affected by chronic otter-trawl disturbance and quantified these effects. Nematode abundance, production, and genus richness declined in response to trawling within both areas. Nematode biomass did not respond to trawling intensity. Genus composition was affected by trawling only in the North Sea. The responses in abundance of individual nematode genera to increasing trawling intensity were negative as well as positive. These results indicate that despite their size and fast life cycle, nematodes are affected by intensive trawling on muddy fishing grounds. The loss in secondary production from nematodes can have far-reaching consequences for the integrity of the benthic food web. As bottom trawl fisheries are expanding into ever deeper muddy habitats, the results presented here are an important step towards understanding the global ecosystem effects of bottom trawling.

Impacts of macrozoobenthic invasions on a temperate coastal food web

2020 ◽  
Vol 653 ◽  
pp. 19-39
Author(s):  
AS Jung ◽  
HW van der Veer ◽  
CJM Philippart ◽  
AM Waser ◽  
BJ Ens ◽  
...  
Keyword(s):  
Food Web ◽  
Native Species ◽  
Wadden Sea ◽  
Marine Species ◽  
Trophic Levels ◽  
Food Web Structure ◽  
Total Consumption ◽  
Predator Prey ◽  
Carbon Transfer ◽  
The Impact

Invasions of marine species are changing coastal food webs worldwide, impacting on trophic interactions between native species (e.g. predator-prey relationships). Here, the impact of 3 macrozoobenthic invasive species on food web structure and functioning at Balgzand (western Wadden Sea) is quantified by using ecological network analysis (ENA). The bivalves Ensis leei and Magallana gigas were observed for the first time in 1984 and 2001, respectively, and the polychaete Marenzelleria viridis appeared in 1989. Although E. leei and M. viridis reached similar peak biomasses in the 2000s (ca. 1700 and 2000 mg C m-2, respectively), the bivalve consumption was higher (>45% of total consumption) than that of the polychaete (<10%). Biomass and impact of M. gigas remained relatively low. E. leei occupied an ecological niche that was relatively unoccupied, which led to competitive advantage with respect to other suspension feeders. Increasing biomass of E. leei coincided with a 70% increase of trophic carbon transfer from primary to secondary producers and an 80% increase from secondary producers to detritus. Carbon flows from secondary producers to higher trophic levels were reduced by more than 60%. These shifts in trophic transfer were stronger than those observed during the invasion of M. gigas in the NE Wadden Sea. At Balgzand, biomass of M. gigas and M. viridis rapidly declined to low values in the 2010s, implying a temporally limited impact. In the 2010s, E. leei was still responsible for 30% of the total consumption in the 2010s, indicating a longer-term impact.

Exploratory data analysis of the interactions among physics, food web structure, and function in two Arctic polynyas

2008 ◽  
Vol 65 (6) ◽  
pp. 1036-1046 ◽  
Author(s):  
Olivier F. Berreville ◽  
Alain F. Vézina ◽  
Keith R. Thompson ◽  
Bert Klein
Keyword(s):  
Food Web ◽  
Seasonal Pattern ◽  
Principal Component ◽  
Open Water ◽  
Seasonal Development ◽  
New Production ◽  
Food Web Structure ◽  
Web Structure ◽  
North Water ◽  
And Function

Polynyas are areas of open water in ice-covered seas, characterized by high biological productivity. The NEW (Northeast Water) and NOW (North Water) polynyas, located off the east and west coasts of Greenland, were extensively sampled in 1993 and 1998, respectively. We used principal component analysis to explore the seasonal covariations among physical, chemical, and ecological characteristics in these polynyas. In both polynyas, the most explanatory eigenvector revealed the expected seasonal development of the bloom (nutrient consumption and biomass increases) associated with declining ice cover, warming, and mixed-layer shallowing. This seasonal pattern, however, was much weaker in NEW than in NOW. No connections between the structure of the food web and recycling processes were apparent in either polynya. The analysis points to much stronger and richer interactions between the mesoplankton (i.e., diatoms–zooplankton) and microbial food webs in NOW than in NEW. The differences between the polynyas may be explained in part by differences in their longevity, with the longer-lived NOW polynya having more time to develop complex trophic interactions. The results also indicate that the connections between food web structure and ecosystem function (i.e., new production versus recycling), at least at the seasonal scale, are weaker than expected.

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