scholarly journals How Do Indirect Effects of Contaminants Inform Ecotoxicology? A Review

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1659
Author(s):  
John W. Fleeger
Keyword(s):  
Indirect Effects ◽  
Field Studies ◽  
Species Interaction ◽  
Sensitive Species ◽  
Chemical Contaminants ◽  
Cascading Effects ◽  
Natural Systems ◽  
As Species ◽  
Long Term Ecological Research

Indirect effects in ecotoxicology are defined as chemical- or pollutant-induced alterations in the density or behavior of sensitive species that have cascading effects on tolerant species in natural systems. As a result, species interaction networks (e.g., interactions associated with predation or competition) may be altered in such a way as to bring about large changes in populations and/or communities that may further cascade to disrupt ecosystem function and services. Field studies and experimental outcomes as well as models indicate that indirect effects are most likely to occur in communities in which the strength of interactions and the sensitivity to contaminants differ markedly among species, and that indirect effects will vary over space and time as species composition, trophic structure, and environmental factors vary. However, knowledge of indirect effects is essential to improve understanding of the potential for chemical harm in natural systems. For example, indirect effects may confound laboratory-based ecological risk assessment by enhancing, masking, or spuriously indicating the direct effect of chemical contaminants. Progress to better anticipate and interpret the significance of indirect effects will be made as monitoring programs and long-term ecological research are conducted that facilitate critical experimental field and mesocosm investigations, and as chemical transport and fate models, individual-based direct effects models, and ecosystem/food web models continue to be improved and become better integrated.

Food web consequences of long-term invasive crayfish control

2013 ◽  
Vol 70 (7) ◽  
pp. 1109-1122 ◽  
Author(s):  
Gretchen J.A. Hansen ◽  
Catherine L. Hein ◽  
Brian M. Roth ◽  
M. Jake Vander Zanden ◽  
Jereme W. Gaeta ◽  
...  
Keyword(s):  
Invasive Species ◽  
Indirect Effects ◽  
Species Interaction ◽  
Benthic Macroinvertebrate ◽  
Rusty Crayfish ◽  
Invasive Crayfish ◽  
Native Crayfish ◽  
Short Time ◽  
Macrophyte Cover

Controlling invasive species can restore ecosystems while also quantifying species interaction strengths. We experimentally removed invasive rusty crayfish (Orconectes rusticus) from a Wisconsin lake. Rusty crayfish abundance declined by 99% in 8 years and did not significantly increase 4 years postharvest, with no compensatory recruitment response observed. Native crayfish (Orconectes virilis) and sunfish (Lepomis spp.) abundances increased by two orders of magnitude as rusty crayfish abundance declined, and macrophyte cover increased significantly in 2–4 m waters. We expected benthic macroinvertebrate densities to increase as rusty crayfish were removed; however, fish consumption of invertebrates increased as rusty crayfish density declined, and macroinvertebrate responses varied among families and habitats. Total Gastropoda density increased 300-fold in cobble, while the density of one gastropod family declined in macrophytes. Ephemeroptera, Odonata, and Amphipoda densities also declined in certain habitats as rusty crayfish were removed, suggesting that they are indirectly facilitated by rusty crayfish. This study highlights the importance of considering indirect effects when assessing the impacts of invasive species and demonstrates that these impacts may be reversed over relatively short time scales.

scholarly journals Timing and duration of phenological subsidies: toward a mechanistic understanding of impacts on community structure and ecosystem processes in stream food chains

2019 ◽  
Author(s):  
Gaku Takimoto ◽  
Takuya Sato
Keyword(s):  
Life History ◽  
Indirect Effects ◽  
Species Interactions ◽  
Community Dynamics ◽  
Food Chains ◽  
Cascading Effects ◽  
Litter Processing ◽  
Phenological Changes ◽  
Field Manipulation

ABSTRACTPhenological resources are common across many ecological communities, and can strongly affect community dynamics. Recent field manipulation experiments in stream food chains found that seasonal timing and duration of terrestrial prey inputs affected the feeding behavior, growth, and maturation of fish predators, caused predator-mediated indirect effects on aquatic prey, and modified trophic-cascading effects on litter processing. These experiments described impacts of resource phenological changes over a few month period, and long-term impacts of continued changes in resource phenology are unknown. Here we develop a mathematical model to extrapolate long-term predictions about the effects of changes in resource phenology from the results of field manipulation experiments. The model predicts that advanced timing generally decreases aquatic prey and litter processing and prolonged duration will either increase or decrease aquatic prey and litter processing depending on the total amount and pre-disturbed timing and duration of terrestrial prey inputs. Importantly, our modeling approach clarifies the mechanisms by which stage-specific responses of life history processes in fish, such as growth, maturation, and reproduction, respond to phenological changes in terrestrial prey inputs and mediate indirect effects on aquatic prey and litter processing. Stage-specific responses of life history processes are an integral part of the mechanisms with which to predict the consequences of phenological species interactions at the community and ecosystem levels.

scholarly journals Cascading effects: insights from the U.S. Long Term Ecological Research Network

Ecosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Christie A. Bahlai ◽  
Clarisse Hart ◽  
Maria T. Kavanaugh ◽  
Jeffrey D. White ◽  
Roger W. Ruess ◽  
...  
Keyword(s):  
Research Network ◽  
Ecological Research ◽  
Cascading Effects ◽  
Long Term Ecological Research ◽  
The U.S

An Ecological Approach to the Study of Highly-Reliable Organizations

2000 ◽  
Vol 44 (22) ◽  
pp. 558-561
Author(s):  
Gene I. Rochlin
Keyword(s):  
Task Performance ◽  
Indirect Effects ◽  
System Performance ◽  
Interface Design ◽  
Field Studies ◽  
Ecological Approach ◽  
Emergent Properties ◽  
Safety Critical ◽  
And Task

Field studies of highly-reliable organizations performing safety-critical tasks in real time demonstrate the importance of understanding both operator and task performance as contingent and emergent properties of interactive and overlapping interactions within and between the operators and their mechanical and organizational “environment.” Since the interface is an integral and constitutive element in the construction of the operator's cognitive field, analysts and designers alike need to remain sensitive to the extent to which changes in interface design or specification can have long-term and indirect effects on system performance and safety.

SELECTION WORK TO IMPROVE PRODUCTIVE AND BREWING QUALITIES OF SPRING BARLEY

1970 ◽  
pp. 38-40
Author(s):  
О. V. Levakova ◽  
L. М. Eroshenko ◽  
А. N. Eroshenko
Keyword(s):  
Protein Content ◽  
Spring Barley ◽  
Humus Content ◽  
Stability Index ◽  
Field Studies ◽  
Climatic Conditions ◽  
Extract Content ◽  
Labile Phosphorus ◽  
Loam Soil

The article presents and analyzes data of competitive varietal testing of promising varieties and lines of spring barley for yield and brewing qualities. Field studies were conducted in 2014–2017 on dark gray forest heavy loam soil. Agrochemical parameters are total nitrogen – 0.24%, humus content in a layer of 0-40 cm (according to Tyurin) – 5.19%, hydrolysis nitrogen – 123.5 mg / kg, salt extract pH – 4.92 mg-eq / 100g; labile phosphorus - 34.6 mg / 100g, labile potassium – 20.0 mg / 100g. The forerunner is winter wheat. Meteorological conditions in the years of research differed from each other and from the average long-term value. Barley samples were assessed by the protein content in the grain (GOST 10846-91), extract content (GOST 12130-77), weight 1000 grains (GOST 10842-89). Ecological plasticity was determined by the method proposed by E.D. Nettevich, A.I. Morgunov and M.I. Maksimenko, stability index (Ľ) by A. A. Gryaznov, indicator of stability level (Puss) by E. D. Nettevich and A. I. Morgunov. The main measure for assessing quality indicators is protein content. Many other biochemical and technological features of grain depend on its level. The experimental data convincingly testify to the significant influence of the soil and climatic conditions on the yield and, especially, on the brewing qualities of barley in the conditions of the Central Region of the Nonchernozem Zone. According to the studied traits, new valuable varieties Nadezhny, Sir, Noble and selection lines 141 / 1-09 h 746, 23 / 1-10 h 784, distinguished by high adaptability and resistance to adverse environmental factors, have been identified.

scholarly journals Connectivity: insights from the U.S. Long Term Ecological Research Network

Ecosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
Author(s):  
David M. Iwaniec ◽  
Michael Gooseff ◽  
Katharine N. Suding ◽  
David Samuel Johnson ◽  
Daniel C. Reed ◽  
...  
Keyword(s):  
Research Network ◽  
Ecological Research ◽  
Long Term Ecological Research ◽  
The U.S

scholarly journals Long Term Interactions of Native and Invasive Species in a Marine Protected Area Suggest Complex Cascading Effects Challenging Conservation Outcomes

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 71
Author(s):  
Charalampos Dimitriadis ◽  
Ivoni Fournari-Konstantinidou ◽  
Laurent Sourbès ◽  
Drosos Koutsoubas ◽  
Stelios Katsanevakis
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
High Performance ◽  
Marine Protected Area ◽  
Habitat Degradation ◽  
Population Increase ◽  
Rocky Reef ◽  
Cascading Effects ◽  
High Level

Understanding the interactions among invasive species, native species and marine protected areas (MPAs), and the long-term regime shifts in MPAs is receiving increased attention, since biological invasions can alter the structure and functioning of the protected ecosystems and challenge conservation efforts. Here we found evidence of marked modifications in the rocky reef associated biota in a Mediterranean MPA from 2009 to 2019 through visual census surveys, due to the presence of invasive species altering the structure of the ecosystem and triggering complex cascading effects on the long term. Low levels of the populations of native high-level predators were accompanied by the population increase and high performance of both native and invasive fish herbivores. Subsequently the overgrazing and habitat degradation resulted in cascading effects towards the diminishing of the native and invasive invertebrate grazers and omnivorous benthic species. Our study represents a good showcase of how invasive species can coexist or exclude native biota and at the same time regulate or out-compete other established invaders and native species.

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