scholarly journals An ecological network approach to predict ecosystem service vulnerability to species losses

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Aislyn A. Keyes ◽  
John P. McLaughlin ◽  
Allison K. Barner ◽  
Laura E. Dee
Keyword(s):  
Ecosystem Services ◽  
Food Web ◽  
Food Webs ◽  
Trophic Level ◽  
Ecosystem Service ◽  
Critical Role ◽  
Network Approach ◽  
Ecological Network ◽  
Additional Species ◽  
Highly Correlated

AbstractHuman-driven threats are changing biodiversity, impacting ecosystem services. The loss of one species can trigger secondary extinctions of additional species, because species interact–yet the consequences of these secondary extinctions for services remain underexplored. Herein, we compare robustness of food webs and the ecosystem services (hereafter ‘services’) they provide; and investigate factors determining service responses to secondary extinctions. Simulating twelve extinction scenarios for estuarine food webs with seven services, we find that food web and service robustness are highly correlated, but that robustness varies across services depending on their trophic level and redundancy. Further, we find that species providing services do not play a critical role in stabilizing food webs – whereas species playing supporting roles in services through interactions are critical to the robustness of both food webs and services. Together, our results reveal indirect risks to services through secondary species losses and predictable differences in vulnerability across services.

scholarly journals Stable Isotope Food Web Analysis of a Large Subtropical Lake: Alternative Explanations for15N Enrichment of Pelagic vs. Littoral Fisheries

2003 ◽  
Vol 3 ◽  
pp. 613-622 ◽  
Author(s):  
Karl E. Havens ◽  
Binhe Gu ◽  
Brian Fry ◽  
Carol Kendall
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Food Webs ◽  
Trophic Level ◽  
Stable Isotope Ratio ◽  
Pelagic Zone ◽  
Primary Producers ◽  
Subtropical Lake ◽  
Primary Consumers ◽  
Habitat Enrichment

The food webs of littoral, pelagic, and littoral-pelagic ecotone (interface) regions of a large subtropical lake were investigated using stable isotope ratio methods, expanding the focus of a previous fish-only study to include other food web components such as primary producers and invertebrates. In these food webs, δ13C increased ~4o/oo and δ15N increased ~10o/oo from primary producers to fish. The δ15N of fish was ~9o/oo in the littoral zone, ~10 o/oo in the ecotone, and ~12o/oo in the pelagic zone. The cross-habitat enrichment in fish15N corresponded with both an increase in the size of fish and an increase in the δ15N of primary consumers (mollusks). Despite larger body size in the pelagic zone, fish in all three habitats appear to occur at the same average trophic level (TL = 4), assuming an enrichment factor of 3.4o/oo per trophic level, and normalizing to the δ15N of primary consumers.

scholarly journals Connecting governance interventions to ecosystem services provision: A social‐ecological network approach

2020 ◽  
Author(s):  
Jean Paul Metzger ◽  
Pedro Fidelman ◽  
Claudia Sattler ◽  
Barbara Schröter ◽  
Martine Maron ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Network Approach ◽  
Ecological Network ◽  
Social Ecological

scholarly journals Top predators govern multitrophic diversity effects in tritrophic food webs

2020 ◽  
Author(s):  
Ruben Ceulemans ◽  
Christian Guill ◽  
Ursula Gaedke
Keyword(s):  
Temporal Variation ◽  
Food Web ◽  
Food Webs ◽  
Functional Diversity ◽  
Trophic Level ◽  
Ecosystem Functioning ◽  
Initial Conditions ◽  
Trophic Levels ◽  
Natural Food ◽  
Model Parameters

AbstractIt is well known that functional diversity strongly affects ecosystem functioning. However, even in rather simple model communities consisting of only two or, at best, three trophic levels, the relationship between multitrophic functional diversity and ecosystem functioning appears difficult to generalize, due to its high contextuality. In this study, we considered several differently structured tritrophic food webs, in which the amount of functional diversity was varied independently on each trophic level. To achieve generalizable results, largely independent of parametrization, we examined the outcomes of 128, 000 parameter combinations sampled from ecologically plausible intervals, with each tested for 200 randomly sampled initial conditions. Analysis of our data was done by training a Random Forest model. This method enables the identification of complex patterns in the data through partial dependence graphs, and the comparison of the relative influence of model parameters, including the degree of diversity, on food web properties. We found that bottom-up and top-down effects cascade simultaneously throughout the food web, intimately linking the effects of functional diversity of any trophic level to the amount of diversity of other trophic levels, which may explain the difficulty in unifying results from previous studies. Strikingly, only with high diversity throughout the whole food web, different interactions synergize to ensure efficient exploitation of the available nutrients and efficient biomass transfer, ultimately leading to a high biomass and production on the top level. The temporal variation of biomass showed a more complex pattern with increasing multitrophic diversity: while the system initially became less variable, eventually the temporal variation rose again due to the increasingly complex dynamical patterns. Importantly, top predator diversity and food web parameters affecting the top trophic level were of highest importance to determine the biomass and temporal variability of any trophic level. Overall, our study reveals that the mechanisms by which diversity influences ecosystem functioning are affected by every part of the food web, hampering the extrapolation of insights from simple monotrophic or bitrophic systems to complex natural food webs.

scholarly journals Author Correction: An ecological network approach to predict ecosystem service vulnerability to species losses

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Aislyn A. Keyes ◽  
John P. McLaughlin ◽  
Allison K. Barner ◽  
Laura E. Dee
Keyword(s):  
Ecosystem Service ◽  
Network Approach ◽  
Ecological Network

scholarly journals Stable Isotope Analyses of Multiple Tissues of Great Shearwaters (Ardenna Gravis) Reveals Long-Term Dietary Stability, Short-Term Changes in Diet, and Can be Used as a Tool to Monitor Food Webs

Diversity ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 163 ◽  
Author(s):  
Hong ◽  
Wiley ◽  
Powers ◽  
Michener ◽  
Kaufman ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Food Webs ◽  
Trophic Level ◽  
Isotope Analysis ◽  
Diet Shift ◽  
Turnover Rates ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Over Time

The great shearwater (Ardenna gravis) is a common pelagic bird with a distribution that spans almost the entire Atlantic basin, which in conjunction with its relatively high abundance, makes great shearwaters an effective bio indicator. We compared δ13C and δ15N values from the feathers, red blood cells (RBCs), and plasma of great shearwaters collected in 2014 and 2015 from the waters off Massachusetts and Cape Cod. The δ13C and δ15N values of RBCs were quite constant between sampling periods and years, suggesting a generally stable food web over that time period. However, the δ13C of plasma indicates a small seasonal change in diet between July and September for both years, with plasma δ15N values suggesting a slight increase in trophic level late in summer. Comparison of the δ15N of RBCs and plasma indicates that great shearwaters experienced a diet shift during the first few weeks of summer 2014, but not in 2015. Comparisons with other studies suggest that these shearwaters feed at a lower trophic level than great shearwaters sampled in the Bay of Fundy and that there is a decrease in δ13C with increasing latitude, which could indicate a more pelagic diet in northern waters. Stable isotope analysis of the sixth primary feathers provided evidence that these feathers are molted in the Northern Hemisphere and that the diet of great shearwaters shortly after arrival was different in 2014 and 2015. This study demonstrates that within species comparisons of tissue isotopic signatures over time and comparisons of isotopic signatures of tissues with different turnover rates, can detect changes in diet and be used as a tool to monitor for changes in marine food webs over time and space. The relevant signals remain informative even in the absence of species-specific data on tissue-diet discrimination factors, tissue turnover rates, or knowledge of dietary components and their stable isotopic signatures, suggesting dietary changes indicative of a corresponding change in the food web.

scholarly journals Phenotypic variation explains food web structural patterns

2017 ◽  
Vol 114 (42) ◽  
pp. 11187-11192 ◽  
Author(s):  
Jean P. Gibert ◽  
John P. DeLong
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Trophic Level ◽  
Phenotypic Variation ◽  
Structural Features ◽  
Trophic Levels ◽  
Intake Rate ◽  
Food Web Structure ◽  
Total Food Intake ◽  
Variation Sets

Food webs (i.e., networks of species and their feeding interactions) share multiple structural features across ecosystems. The factors explaining such similarities are still debated, and the role played by most organismal traits and their intraspecific variation is unknown. Here, we assess how variation in traits controlling predator–prey interactions (e.g., body size) affects food web structure. We show that larger phenotypic variation increases connectivity among predators and their prey as well as total food intake rate. For predators able to eat only a few species (i.e., specialists), low phenotypic variation maximizes intake rates, while the opposite is true for consumers with broader diets (i.e., generalists). We also show that variation sets predator trophic level by determining interaction strengths with prey at different trophic levels. Merging these results, we make two general predictions about the structure of food webs: (i) trophic level should increase with predator connectivity, and (ii) interaction strengths should decrease with prey trophic level. We confirm these predictions empirically using a global dataset of well-resolved food webs. Our results provide understanding of the processes structuring food webs that include functional traits and their naturally occurring variation.

scholarly journals Interplay between the paradox of enrichment and nutrient cycling in food webs

2018 ◽  
Author(s):  
Pierre Quévreux ◽  
Sébastien Barot ◽  
Élisa Thébault
Keyword(s):  
Nutrient Cycling ◽  
Food Web ◽  
Food Webs ◽  
Trophic Level ◽  
Temporal Variability ◽  
Ecosystem Functioning ◽  
Nutrient Inputs ◽  
Primary Producers ◽  
Paradox Of Enrichment ◽  
Food Web Dynamics

AbstractNutrient cycling is fundamental to ecosystem functioning. Despite recent major advances in the understanding of complex food web dynamics, food web models have so far generally ignored nutrient cycling. However, nutrient cycling is expected to strongly impact food web stability and functioning. To make up for this gap, we built an allometric and size structured food web model including nutrient cycling. By releasing mineral nutrients, recycling increases the availability of limiting resources for primary producers and links each trophic level to the bottom of food webs. We found that nutrient cycling can provide a significant part of the total nutrient supply of the food web, leading to a strong enrichment effect that promotes species persistence in nutrient poor ecosystems but leads to a paradox of enrichment at high nutrient inputs. The presence of recycling loops linking each trophic level to the basal resources weakly affects species biomass temporal variability in the food web. Recycling loops tend to slightly dampen the destabilising effect of nutrient enrichment on consumer temporal variability while they have opposite effects for primary producers. By considering nutrient cycling, this new model improves our understanding of the response of food webs to nutrient availability and opens perspectives to better link studies on food web dynamics and ecosystem functioning.

scholarly journals Fuzzy cognitive mapping of Baltic Archipelago Sea food webs reveals no cliqued views of the system structure between stakeholder groups

2020 ◽  
Vol 2 ◽  
pp. 16343
Author(s):  
Laura Uusitalo ◽  
Susanna Jernberg ◽  
Patrik Korn ◽  
Riikka Puntila-Dodd ◽  
Annaliina Skyttä ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Food Web ◽  
Food Webs ◽  
Cognitive Mapping ◽  
Stakeholder Group ◽  
Ecosystem Structure ◽  
Food Web Structure ◽  
Stakeholder Groups ◽  
Web Structure ◽  
Archipelago Sea

Incorporating stakeholder views is a key element in successful environmental management, particularly if the managed system delivers cultural and provisioning ecosystem services directly to the stakeholders, or if there are conflicting views about the ecosystem functioning or its optimal management. One such system is the Archipelago Sea in the Southwestern coast of Finland. It is an area with high biodiversity, offering a range of ecosystem services, from regulating services to provisioning and cultural services. Furthermore, it is subjected to a variety of human activities ranging from eutrophication and marine transport to fishing. The management of the area is also a topic of debate, including discussions of minimum landing size of fish, seal hunting quotas, and the role of cormorants in the ecosystem. Fuzzy cognitive mapping  offers a method to evaluate and quantitatively compare different actors’ views on ecosystem structure. The models can be compared quantitatively and simulated to illustrate how they respond to various pressure scenarios. This may reveal differences in the perceptions about what are the important interactions in the ecosystem, and how the system would respond to management measures, potentially explaining differing opinions about the best management strategy. In this work, 30 stakeholders, including policy makers, scientists, eNGOs, fisheries, and recreational users created fuzzy cognitive maps (FCMs) of the Archipelago Sea food web. We found that despite the debate about the management of the area, the stakeholders’ views about the food web structure were not clustered based on the stakeholder group, i.e. the different stakeholder groups did not have distinct ideas about the ecosystem structure. The FCM complexity did not show a pattern based on the stakeholder group either. While the general pattern of the FCMs indicated a shared view of the food web structure across most respondents, there was one map from the recreational group that stood out. The exact setup of the models varied. Across all maps, cod, perch, fishing, zooplankton, and herring were the variables having most links with the other variables.  The simulated ecosystem responses indicated that fishing was seen as a key factor affecting food web components, while increases of salinity and oxygen levels have a positive impact on multiple ecosystem components. The value of the approach is to enable a two-way discussion about the food webs and how management of pressures may impact the components.

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