Food web characteristics of fish communities across degraded lakes provide insights for management in multi-stressor environments

Stable isotope analysis is one of the most widely used techniques to estimate trophic position and provides fundamental insight into the structure and management of ecological communities. To account for the effects of geographic variation in isotope levels, trophic position is typically estimated relative to an isotope “baseline” (i.e., material representing geographic variation) using a methodology such as a formula or statistical analysis. There is, however, remarkable variation in the baselines and methodologies used to estimate trophic position from stable isotopes. The consequences of this lack of standardization are unknown but could result in biased or erroneous conclusions. We conducted a literature review to quantify the variation in baselines and methodologies used to estimate trophic position from stable isotopes. Next, we assessed the consequences of this variation on individual species estimates and food web structure by extracting published trophic positions and applying various baselines and methodologies to existing data sets. We identified 10 baselines and eight methodologies, the use of which varied by ecosystem studied. Moreover, we found that different baselines and methodologies yield significantly different trophic position estimates for individual species, as well as different conclusions about food web structure. Authors should avoid biological interpretations of absolute, stand‐alone trophic positions (as these are prone to a number of biases). We recommend pairing stable isotope analysis with other techniques for more robust conclusions. Increased sample size may mitigate some of the variation caused by different baselines and methodologies; however, an alarmingly large proportion of studies collected only one sample in at least one trophic group (41% of all reviewed studies). Authors should collect a minimum of five samples per trophic group (but ten for best practices) from as many trophic groups as possible to increase statistical power and redundancy in comparisons. When sample size is unavoidably constrained, we recommend using compound‐specific isotope analysis with a taxon‐specific trophic discrimination factor, because it may be more accurate and require fewer samples to maintain appropriate statistical power. Implementing our recommendations will increase the robustness and accuracy of conclusions based on stable isotopes, resulting in better management decisions and a more accurate understanding of ecological communities.

show abstract

“…2020, Pingram et al. 2020), and to quantify recovery after restoration (Senior et al. 2013, James et al.…”

Section: Introductionmentioning

confidence: 99%

Widespread variation in stable isotope trophic position estimates: patterns, causes, and potential consequences

Kjeldgaard

Hewlett

Eubanks

2021

Ecological Monographs

View full text Add to dashboard Cite

show abstract

“…There is evidence that invasive secondary consumers caused decreases in the core isotopic niche size, the δ 13 C range of recipient communities, and the total isotopic niche of coexisting native species (Sagouis et al., 2015). Furthermore, interactions among invasive species may compound their trophic effects on native communities (Pingram et al., 2020). Numerous aquatic invasive species (e.g., zebra and quagga mussels ( Dreissena spp.…”

Section: Discussionmentioning

confidence: 99%

Ecosystem Response Through a Resilience Lens: Do Differences in the Illinois River Over 150 Y Indicate Regime Shifts?

DeBoer

Thoms

2021

JGR Biogeosciences

View full text Add to dashboard Cite

Understanding the response of large river ecosystems to anthropogenic stressors, and their interactions with natural system disturbances, is challenging (Stanley et al., 2010). Ecosystems are inherently dynamic, changing both naturally and in response to anthropogenic stressors. Understanding how and why ecosystems change is central to ecosystem science (Sutherland et al., 2013), and river ecosystems-like other complex systems-are characterized by self-organization, nonlinear dynamics, and the potential for multiple stable states (Folke et al., 2010;Holling & Gunderson, 2002). Anthropogenic activities are increasingly pervasive and superimposed on the natural river template. Research that distinguishes between natural and human contributions to the "disturbance regime" of large river ecosystems has been limited to date (cf. Gupta, 2021;Hampton et al., 2019;Thoms & Sheldon, 2019). The lack of integrated conceptual frameworks (Ormerod et al., 2010) and long-term data (Hampton et al., 2019) restricts current efforts to understand the effect of multiple stressors in large river ecosystems (Craig et al., 2017).Resilience thinking is a model for examining change in ecosystems. Complex systems are conceptualized to have dynamic trajectories that may not tend toward equilibrium conditions; rather, they move through an adaptive cycle in response to resource variations. Adaptive cycles characterize change as a cycle comprised of four phases:

show abstract

“…The interplay between land use change, non-native fish and eutrophication in contemporary environments (e.g. Pingram et al, 2020) is a clear example of this complex multiple-stressor environment. Reid et al (2019) reviews the complexities of multiple-stressor impacts in freshwater ecosystems (e.g.…”

Section: Responses Of Native Fish Communities To Disturbances In Lakesmentioning

confidence: 99%

An integrative approach to assess the impact of disturbance on native fish in lakes

Thomson‐Laing,

Schallenberg,

Kelly

et al. 2023

Biological Reviews

View full text Add to dashboard Cite

Freshwater fish are in a perilous state with more than 30% of species considered critically endangered. Yet significant ecological and methodological complexities constrain our ability to determine how disturbances are impacting native fish communities. We review current methods used to assess the responses of fish communities, especially native fish, to disturbances, with a focus on lakes. These methods include contemporary population surveys, manipulative experimental approaches, paleolimnological approaches and Indigenous Knowledge and social histories. We identify knowledge gaps, such as a lack of baseline data for native fish, an inability to assess the impact of historical disturbances, stressor response dynamics in contemporary multi‐stressor environments, and natural disturbance regimes. Our assessment of the current methods highlights challenges to filling these knowledge gaps using the reviewed methods. We advocate strongly for the implementation of an integrative approach that combines emerging technologies (i.e. molecular‐based techniques in contemporary surveys and paleolimnology) and underutilised knowledge streams (i.e. Indigenous Knowledge and social histories) which should be used in concert with conventional methods. This integrative approach will allow researchers to determine the key drivers of decline and the degree of change, which will enable more informed and successful management actions.

show abstract

Food web characteristics of fish communities across degraded lakes provide insights for management in multi-stressor environments

Cited by 11 publications

References 77 publications

Widespread variation in stable isotope trophic position estimates: patterns, causes, and potential consequences

Widespread variation in stable isotope trophic position estimates: patterns, causes, and potential consequences

Ecosystem Response Through a Resilience Lens: Do Differences in the Illinois River Over 150 Y Indicate Regime Shifts?

An integrative approach to assess the impact of disturbance on native fish in lakes

Contact Info

Product

Resources

About