DOCSLIB.ORG

An Extended Ecosystem Model for Understanding EE2 Indirect Effects

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
An Extended Ecosystem Model for Understanding EE2 Indirect Effects water Article An Extended Ecosystem Model for Understanding EE2 Indirect Effects on a Freshwater Food Web and Its Ecosystem Function Resilience Ludiwine Clouzot, Charlotte Haguenauer and Peter A. Vanrolleghem * modelEAU, Université Laval, Québec, QC G1V 0A6, Canada; [email protected] (L.C.); [email protected] (C.H.) * Correspondence: [email protected] Received: 8 May 2020; Accepted: 15 June 2020; Published: 17 June 2020 Abstract: Freshwater species are highly impacted by human activities and the consequences on ecosystem functioning are still not well understood. In the literature, a multitrophic perspective appears to be key to advance future biodiversity and ecosystem functioning (BEF) research. This paper aims at studying indirect effects of the synthetic hormone 17α-ethinylestradiol (EE2) on a freshwater food web by creating BEF links, through the interpretation of seasonal cycles and multitrophic interactions. An ecosystem model previously developed using experimental data from a unique whole-ecosystem study on EE2 was extended with the addition of Chaoborus, an omnivorous insect. During the experimental study, a collapse of fathead minnow was measured after one year of exposure. The simulation results showed that EE2 indirect effects on other fishes (horizontal diversity) and lower trophic levels (vertical diversity) were connected to multitrophic interactions with a top-down cascade effect. The results also demonstrated that adding an omnivorous, mid-trophic level group such as Chaoborus enhances resilience. Conversely, missing such a species means that the actual resilience of an ecosystem and its functioning cannot be properly simulated. Thus, the extended ecosystem model offers a tool that can help better understand what is happening after environmental perturbations, such as with EE2. Keywords: 17(alpha)-ethinylestradiol; biodiversity; Chaoborus; ecological function; experimental lake area; freshwater ecosystem; multitrophic interactions 1. Introduction Pharmaceuticals and hormones are continuously entering the environment through release from wastewater treatment plants (WWTPs). In the last few decades, the occurrence of those emerging compounds has increasingly received attention due to their harm to the ecosystem. A review on worldwide environmental monitoring of water organic pollutants identified by European guidelines [1,2]demonstrated that pharmaceuticals represent the most studied class of Watch List compounds (42.9%), the natural estrogens E1 and E2 and the synthetic 17α-ethinylestradiol (EE2) being the second most studied (35.3%). Both the natural and synthetic hormones were previously identified as the main substances responsible for estrogenic activities in WWTPs, with concentrations as low as ng/L, sometimes exceeding their predicted no-effect concentrations (PNECs) for ecological toxicity [3]. Species responses to these environmental estrogens vary considerably, with fishes having much higher sensitivities than invertebrates [4,5]. Indirect effects on tolerant species, mediated by ecological mechanisms, may also appear in the environment but cannot be measured by single species laboratory-based toxicity tests; this is why population, community or ecosystem level studies are required [6]. EE2, one of the most potent synthetic estrogens, interferes in multiple ways with the activity of different physiological endpoints of aquatic organisms, including the endocrine system [7–10]. In a Water 2020, 12, 1736; doi:10.3390/w12061736 www.mdpi.com/journal/water Water 2020, 12, 1736 2 of 22 multi-year whole-ecosystem study performed at an experimental lake, [11] exposed well-defined fish and lower-trophic level populations to environmentally relevant concentrations of EE2. During this experimental study, a collapse of fathead minnow was measured after one year of exposure to EE2. A mix of reduced gamete production, increased gamete mortality and an increase of both adults and juvenile mortality was hypothesized to explain the collapse of both adult and juvenile fathead minnow due to EE2 addition in reference [12]. Since several small fishes declined in the experimental lake after EE2 additions, the authors sought evidence for a trophic cascade resulting from the associated reductions in planktivory and benthivory fish [13]. Trophic cascades (indirect effects mediated through consumer–resource interactions) are a well-studied type of indirect effect, and are generally considered in terms of ‘top–down’ (predator influence on lower trophic levels) or ‘bottom–up’ (nutrient/food/prey influence on higher trophic levels) mechanism [6]. Unlike the many studies that have shown direct effects of estrogens and their mimics on aquatic species, especially fishes, Kidd et al. [13] advance the understanding of how estrogen-induced changes in fish abundance can lead to indirect effects on freshwater food webs. This paper aims at taking further their interpretation of the direct and indirect effects of EE2 by modeling links between aquatic biodiversity and ecological functioning. In terms of extinction risk, freshwater species are among the world’s most threatened [14]. Thus, one important question to be answered is: “To what extent does species loss from freshwaters affect ecosystem functioning and their ability to provide ecosystem goods and services for people?”. “Ecosystem function” (EF) is a general term that includes stocks of materials (e.g., carbon, water and mineral nutrients) and rates of processes involving fluxes of energy and matter between trophic levels and the environment. EFs are linked to biodiversity, and can thus be broadly defined as the biological, geochemical and physical processes that take place or occur within an ecosystem. Due to such complexity, the underlying role of biodiversity in ecosystem functioning, its relevance for ecosystem service provision in general, as well as the consequences of its decline, remain poorly understood [15]. A multitrophic perspective is key to advancing future biodiversity and ecosystem functioning (BEF) research and to address some of its most important remaining challenges [16]. Research on biodiversity and ecosystem functioning is one of the most prominent topics investigated by ecologists in the last three decades, with two new domains (Aquatic Food Webs and Agricultural Landscapes) arising in the last decade [17]. Besides, the “ecosystem service” has become the most prominent science policy term used in the last 8 years (2011–2018). Ecosystem-based management (EBM) is a collaborative management approach used with the intention to restore, enhance and protect the resilience of an ecosystem so as to sustain or improve ecosystem services (ES) and protect biodiversity, while considering nature and society [18]. In their review, Eisenhauer et al. [16] concluded that understanding why and how the strength of biodiversity effects varies with environmental conditions and at which spatial scales different mechanisms operate, will be key to operationalize BEF insights for ecosystem management, society and decision making. Duffy et al. [19] pointed out that understanding how biodiversity affects functioning of complex ecosystems will benefit from integrating theory and experiments with simulations and network-based approaches. Indeed, integrated models could highlight priorities for the collection of new empirical data, identify gaps in our existing theories of how ecosystems work, help develop new concepts for how biodiversity composition and ecosystem function interact, and allow predicting BEF relations and its drivers at larger scales [20]. Besides, Queirós et al. [21] identified a need to translate observed mechanisms (short-term and single species) into conceptual models that include combinations of species and environmental gradients not yet observed (multiple stressors, long-term and interacting species). According to Barnes et al. [22], integrating trophic complexity is key to understanding how biodiversity affects whole-ecosystem functioning. Therefore, this study takes up the challenge to improve an ecosystem model that was previously developed and successfully calibrated [12], with the addition of Chaoborus, an omnivorous insect that is an important food source for higher trophic levels and preys on lower trophic levels. This extended ecosystem model will be used to confirm and take Water 2020, 12, 1736 3 of 22 further the hypotheses on EE2 indirect effects on a freshwater food web [13]. Besides, indirect EE2 effects will be compared with and without the presence of Chaoborus in the food web. Finally, how the presence of Chaoborus enhances the resilience of ecosystem functioning will be discussed. Consultation with the ecologists observing the ecosystem was made to verify that major ecosystem mechanisms were correctly represented in the model. This was necessary as a first-order assessment of model reliability when extrapolated to conditions beyond the observed state [21]. The results presented in this paper will support the transition of BEF from a description of patterns to a predictive science [16], which can help better understand the link between biodiversity and ecosystem functioning in the context of EBM. 2. Materials and Methods 2.1. Step 1: Collecting Experimental Data The experimental data used for the model were collected during a multi-year whole-lake study on Lake 260 in the Experimental Lakes Area (ELA) in northwestern Ontario, Canada (all sampling details can be found in [13]). This experimental lake is oligotrophic (high oxygen
Load more

Recommended publications
  • Freshwater Ecosystems and Biodiversity
    Network of Conservation Educators & Practitioners Freshwater Ecosystems and Biodiversity Author(s): Nathaniel P. Hitt, Lisa K. Bonneau, Kunjuraman V. Jayachandran, and Michael P. Marchetti Source: Lessons in Conservation, Vol. 5, pp. 5-16 Published by: Network of Conservation Educators and Practitioners, Center for Biodiversity and Conservation, American Museum of Natural History Stable URL: ncep.amnh.org/linc/ This article is featured in Lessons in Conservation, the official journal of the Network of Conservation Educators and Practitioners (NCEP). NCEP is a collaborative project of the American Museum of Natural History’s Center for Biodiversity and Conservation (CBC) and a number of institutions and individuals around the world. Lessons in Conservation is designed to introduce NCEP teaching and learning resources (or “modules”) to a broad audience. NCEP modules are designed for undergraduate and professional level education. These modules—and many more on a variety of conservation topics—are available for free download at our website, ncep.amnh.org. To learn more about NCEP, visit our website: ncep.amnh.org. All reproduction or distribution must provide full citation of the original work and provide a copyright notice as follows: “Copyright 2015, by the authors of the material and the Center for Biodiversity and Conservation of the American Museum of Natural History. All rights reserved.” Illustrations obtained from the American Museum of Natural History’s library: images.library.amnh.org/digital/ SYNTHESIS 5 Freshwater Ecosystems and Biodiversity Nathaniel P. Hitt1, Lisa K. Bonneau2, Kunjuraman V. Jayachandran3, and Michael P. Marchetti4 1U.S. Geological Survey, Leetown Science Center, USA, 2Metropolitan Community College-Blue River, USA, 3Kerala Agricultural University, India, 4School of Science, St.
    [Show full text]
  • Ecosystem Services Generated by Fish Populations
    AR-211 Ecological Economics 29 (1999) 253 –268 ANALYSIS Ecosystem services generated by fish populations Cecilia M. Holmlund *, Monica Hammer Natural Resources Management, Department of Systems Ecology, Stockholm University, S-106 91, Stockholm, Sweden Abstract In this paper, we review the role of fish populations in generating ecosystem services based on documented ecological functions and human demands of fish. The ongoing overexploitation of global fish resources concerns our societies, not only in terms of decreasing fish populations important for consumption and recreational activities. Rather, a number of ecosystem services generated by fish populations are also at risk, with consequences for biodiversity, ecosystem functioning, and ultimately human welfare. Examples are provided from marine and freshwater ecosystems, in various parts of the world, and include all life-stages of fish. Ecosystem services are here defined as fundamental services for maintaining ecosystem functioning and resilience, or demand-derived services based on human values. To secure the generation of ecosystem services from fish populations, management approaches need to address the fact that fish are embedded in ecosystems and that substitutions for declining populations and habitat losses, such as fish stocking and nature reserves, rarely replace losses of all services. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Ecosystem services; Fish populations; Fisheries management; Biodiversity 1. Introduction 15 000 are marine and nearly 10 000 are freshwa­ ter (Nelson, 1994). Global capture fisheries har­ Fish constitute one of the major protein sources vested 101 million tonnes of fish including 27 for humans around the world. There are to date million tonnes of bycatch in 1995, and 11 million some 25 000 different known fish species of which tonnes were produced in aquaculture the same year (FAO, 1997).
    [Show full text]
  • An Assessment of Marine Ecosystem Damage from the Penglai 19-3 Oil Spill Accident
    Journal of Marine Science and Engineering Article An Assessment of Marine Ecosystem Damage from the Penglai 19-3 Oil Spill Accident Haiwen Han 1, Shengmao Huang 1, Shuang Liu 2,3,*, Jingjing Sha 2,3 and Xianqing Lv 1,* 1 Key Laboratory of Physical Oceanography, Ministry of Education, Ocean University of China, Qingdao 266100, China; [email protected] (H.H.); [email protected] (S.H.) 2 North China Sea Environment Monitoring Center, State Oceanic Administration (SOA), Qingdao 266033, China; [email protected] 3 Department of Environment and Ecology, Shandong Province Key Laboratory of Marine Ecology and Environment & Disaster Prevention and Mitigation, Qingdao 266100, China * Correspondence: [email protected] (S.L.); [email protected] (X.L.) Abstract: Oil spills have immediate adverse effects on marine ecological functions. Accurate as- sessment of the damage caused by the oil spill is of great significance for the protection of marine ecosystems. In this study the observation data of Chaetoceros and shellfish before and after the Penglai 19-3 oil spill in the Bohai Sea were analyzed by the least-squares fitting method and radial basis function (RBF) interpolation. Besides, an oil transport model is provided which considers both the hydrodynamic mechanism and monitoring data to accurately simulate the spatial and temporal distribution of total petroleum hydrocarbons (TPH) in the Bohai Sea. It was found that the abundance of Chaetoceros and shellfish exposed to the oil spill decreased rapidly. The biomass loss of Chaetoceros and shellfish are 7.25 × 1014 ∼ 7.28 × 1014 ind and 2.30 × 1012 ∼ 2.51 × 1012 ind in the area with TPH over 50 mg/m3 during the observation period, respectively.
    [Show full text]
  • Chesapeake Bay Trust Hypoxia Project
    Chesapeake Bay dissolved oxygen profiling using a lightweight, low- powered, real-time inductive CTDO2 mooring with sensors at multiple vertical measurement levels Doug Wilson Caribbean Wind LLC Baltimore, MD Darius Miller SoundNine Inc. Kirkland, WA Chesapeake Bay Trust EPA Chesapeake Bay Program Goal Implementation Team Support This project has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement CB96341401 to the Chesapeake Bay Trust. The contents of this document do not necessarily reflect the views and policies of the Environmental Protection Agency, nor does the EPA endorse trade names or recommend the use of commercial products mentioned in this document. SCOPE 8: “…demonstrate a reliable, cost effective, real-time dissolved oxygen vertical monitoring system for characterizing mainstem Chesapeake Bay hypoxia.” Water quality impairment in the Chesapeake Bay, caused primarily by excessive long-term nutrient input from runoff and groundwater, is characterized by extreme seasonal hypoxia, particularly in the bottom layers of the deeper mainstem (although it is often present elsewhere). In addition to obvious negative impacts on ecosystems where it occurs, hypoxia represents the integrated effect of watershed-wide nutrient pollution, and monitoring the size and location of the hypoxic regions is important to assessing Chesapeake Bay health and restoration progress. Chesapeake Bay Program direct mainstem water quality monitoring has been by necessity widely spaced in time and location, with monthly or bi-monthly single fixed stations separated by several kilometers. The need for continuous, real time, vertically sampled profiles of dissolved oxygen has been long recognized, and improvements in hypoxia modeling and sensor technology make it achievable.
    [Show full text]
  • Vegetation Demographics in Earth System Models: a Review of Progress and Priorities
    Lawrence Berkeley National Laboratory Recent Work Title Vegetation demographics in Earth System Models: A review of progress and priorities. Permalink https://escholarship.org/uc/item/3912p4m3 Journal Global change biology, 24(1) ISSN 1354-1013 Authors Fisher, Rosie A Koven, Charles D Anderegg, William RL et al. Publication Date 2018 DOI 10.1111/gcb.13910 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Received: 11 April 2017 | Revised: 12 August 2017 | Accepted: 17 August 2017 DOI: 10.1111/gcb.13910 RESEARCH REVIEW Vegetation demographics in Earth System Models: A review of progress and priorities Rosie A. Fisher1 | Charles D. Koven2 | William R. L. Anderegg3 | Bradley O. Christoffersen4 | Michael C. Dietze5 | Caroline E. Farrior6 | Jennifer A. Holm2 | George C. Hurtt7 | Ryan G. Knox2 | Peter J. Lawrence1 | Jeremy W. Lichstein8 | Marcos Longo9 | Ashley M. Matheny10 | David Medvigy11 | Helene C. Muller-Landau12 | Thomas L. Powell2 | Shawn P. Serbin13 | Hisashi Sato14 | Jacquelyn K. Shuman1 | Benjamin Smith15 | Anna T. Trugman16 | Toni Viskari12 | Hans Verbeeck17 | Ensheng Weng18 | Chonggang Xu4 | Xiangtao Xu19 | Tao Zhang8 | Paul R. Moorcroft20 1National Center for Atmospheric Research, Boulder, CO, USA 2Lawrence Berkeley National Laboratory, Berkeley, CA, USA 3Department of Biology, University of Utah, Salt Lake City, UT, USA 4Los Alamos National Laboratory, Los Alamos, NM, USA 5Department of Earth and Environment, Boston University, Boston, MA, USA 6Department of Integrative Biology,
    [Show full text]
  • Manual for Phytoplankton Sampling and Analysis in the Black Sea
    Manual for Phytoplankton Sampling and Analysis in the Black Sea Dr. Snejana Moncheva Dr. Bill Parr Institute of Oceanology, Bulgarian UNDP-GEF Black Sea Ecosystem Academy of Sciences, Recovery Project Varna, 9000, Dolmabahce Sarayi, II. Hareket P.O.Box 152 Kosku 80680 Besiktas, Bulgaria Istanbul - TURKEY Updated June 2010 2 Table of Contents 1. INTRODUCTION........................................................................................................ 5 1.1 Basic documents used............................................................................................... 1.2 Phytoplankton – definition and rationale .............................................................. 1.3 The main objectives of phytoplankton community analysis ........................... 1.4 Phytoplankton communities in the Black Sea ..................................................... 2. SAMPLING ................................................................................................................. 9 2.1 Site selection................................................................................................................. 2.2 Depth ............................................................................................................................... 2.3 Frequency and seasonality ....................................................................................... 2.4 Algal Blooms................................................................................................................. 2.4.1 Phytoplankton bloom detection
    [Show full text]
  • Emergent Biogeography of Microbial Communities in a Model Ocean
    REPORTS germ insects not only uncovers those features es- mRNA localization indeed appears to be an sential to this developmental mode but also sheds important component of long-germ embryogene- light on how the bcd-dependent anterior patterning sis, perhaps even playing a role in the transition program might have evolved. Through analysis of from the ancestral short-germ to the derived long- the regulation of the trunk gap gene Kr in Dro- germ fate. sophila and Nasonia,wehavebeenabletodem- onstrate that anterior repression of Kr is essential References and Notes for head and thorax formation and is a common 1. G. K. Davis, N. H. Patel, Annu. Rev. Entomol. 47, 669 (2002). feature of long-germ patterning. Both insects 2. T. Berleth et al., EMBO J. 7, 1749 (1988). accomplish this task through maternal, anteriorly 3. W. Driever, C. Nusslein-Volhard, Cell 54, 83 (1988). localized factors that either indirectly (Drosophila) 4. J. Lynch, C. Desplan, Curr. Biol. 13, R557 (2003). or directly (Nasonia) repress Kr and, hence, trunk 5. J. A. Lynch, A. E. Brent, D. S. Leaf, M. A. Pultz, C. Desplan, Nature 439, 728 (2006). fates. In Drosophila, the terminal system and bcd 6. J. Savard et al., Genome Res. 16, 1334 (2006). regulate expression of gap genes, including Dm-gt, 7. G. Struhl, P. Johnston, P. A. Lawrence, Cell 69, 237 (1992). that repress Dm-Kr. Nasonia’s bcd-independent 8. A. Preiss, U. B. Rosenberg, A. Kienlin, E. Seifert, long-germ embryos must solve the same problem, H. Jackle, Nature 313, 27 (1985). Fig. 4.
    [Show full text]
  • Lake Superior Phototrophic Picoplankton: Nitrate Assimilation
    LAKE SUPERIOR PHOTOTROPHIC PICOPLANKTON: NITRATE ASSIMILATION MEASURED WITH A CYANOBACTERIAL NITRATE-RESPONSIVE BIOREPORTER AND GENETIC DIVERSITY OF THE NATURAL COMMUNITY Natalia Valeryevna Ivanikova A Dissertation Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 2006 Committee: George S. Bullerjahn, Advisor Robert M. McKay Scott O. Rogers Paul F. Morris Robert K. Vincent Graduate College representative ii ABSTRACT George S. Bullerjahn, Advisor Cyanobacteria of the picoplankton size range (picocyanobacteria) Synechococcus and Prochlorococcus contribute significantly to total phytoplankton biomass and primary production in marine and freshwater oligotrophic environments. Despite their importance, little is known about the biodiversity and physiology of freshwater picocyanobacteria. Lake Superior is an ultra- oligotrophic system with light and temperature conditions unfavorable for photosynthesis. Synechococcus-like picocyanobacteria are an important component of phytoplankton in Lake Superior. The concentration of nitrate, the major form of combined nitrogen in the lake, has been increasing continuously in these waters over the last 100 years, while other nutrients remained largely unchanged. Decreased biological demand for nitrate caused by low availabilities of phosphorus and iron, as well as low light and temperature was hypothesized to be one of the reasons for the nitrate build-up. One way to get insight into the microbiological processes that contribute to the accumulation of nitrate in this ecosystem is to employ a cyanobacterial bioreporter capable of assessing the nitrate assimilation capacity of phytoplankton. In this study, a nitrate-responsive biorepoter AND100 was constructed by fusing the promoter of the Synechocystis PCC 6803 nitrate responsive gene nirA, encoding nitrite reductase to the Vibrio fischeri luxAB genes, which encode the bacterial luciferase, and genetically transforming the resulting construct into Synechocystis.
    [Show full text]
  • Meta-Ecosystems: a Theoretical Framework for a Spatial Ecosystem Ecology
    Ecology Letters, (2003) 6: 673–679 doi: 10.1046/j.1461-0248.2003.00483.x IDEAS AND PERSPECTIVES Meta-ecosystems: a theoretical framework for a spatial ecosystem ecology Abstract Michel Loreau1*, Nicolas This contribution proposes the meta-ecosystem concept as a natural extension of the Mouquet2,4 and Robert D. Holt3 metapopulation and metacommunity concepts. A meta-ecosystem is defined as a set of 1Laboratoire d’Ecologie, UMR ecosystems connected by spatial flows of energy, materials and organisms across 7625, Ecole Normale Supe´rieure, ecosystem boundaries. This concept provides a powerful theoretical tool to understand 46 rue d’Ulm, F–75230 Paris the emergent properties that arise from spatial coupling of local ecosystems, such as Cedex 05, France global source–sink constraints, diversity–productivity patterns, stabilization of ecosystem 2Department of Biological processes and indirect interactions at landscape or regional scales. The meta-ecosystem Science and School of perspective thereby has the potential to integrate the perspectives of community and Computational Science and Information Technology, Florida landscape ecology, to provide novel fundamental insights into the dynamics and State University, Tallahassee, FL functioning of ecosystems from local to global scales, and to increase our ability to 32306-1100, USA predict the consequences of land-use changes on biodiversity and the provision of 3Department of Zoology, ecosystem services to human societies. University of Florida, 111 Bartram Hall, Gainesville, FL Keywords 32611-8525,
    [Show full text]
  • Advances in the Monitoring of Algal Blooms by Remote Sensing: a Bibliometric Analysis
    applied sciences Article Advances in the Monitoring of Algal Blooms by Remote Sensing: A Bibliometric Analysis Maria-Teresa Sebastiá-Frasquet 1,* , Jesús-A Aguilar-Maldonado 1 , Iván Herrero-Durá 2 , Eduardo Santamaría-del-Ángel 3 , Sergio Morell-Monzó 1 and Javier Estornell 4 1 Instituto de Investigación para la Gestión Integrada de Zonas Costeras, Universitat Politècnica de València, C/Paraninfo, 1, 46730 Grau de Gandia, Spain; [email protected] (J.-A.A.-M.); [email protected] (S.M.-M.) 2 KFB Acoustics Sp. z o. o. Mydlana 7, 51-502 Wrocław, Poland; [email protected] 3 Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada 22860, Mexico; [email protected] 4 Geo-Environmental Cartography and Remote Sensing Group, Universitat Politècnica de València, Camí de Vera s/n, 46022 Valencia, Spain; [email protected] * Correspondence: [email protected] Received: 20 September 2020; Accepted: 4 November 2020; Published: 6 November 2020 Abstract: Since remote sensing of ocean colour began in 1978, several ocean-colour sensors have been launched to measure ocean properties. These measures have been applied to study water quality, and they specifically can be used to study algal blooms. Blooms are a natural phenomenon that, due to anthropogenic activities, appear to have increased in frequency, intensity, and geographic distribution. This paper aims to provide a systematic analysis of research on remote sensing of algal blooms during 1999–2019 via bibliometric technique. This study aims to reveal the limitations of current studies to analyse climatic variability effect. A total of 1292 peer-reviewed articles published between January 1999 and December 2019 were collected.
    [Show full text]
  • Chapter 4 – Steady State Models
    CHAPTER 4 Steady State Models X.-Z. Kong, F.-L. Xu1, W. He, W.-X. Liu, B. Yang Peking University, Beijing, China 1Corresponding author: E-mail: xufl@urban.pku.edu.cn OUTLINE 4.1 Steady State Model: Ecopath as an 4.2.4.2 Changes in Ecosystem Example 66 Functioning 79 4.1.1 Steady State Model 66 4.2.4.3 Collapse in the Food 4.1.2 Ecopath Model 66 Web: Differences in 4.1.3 Future Perspectives 68 Structure 81 4.2.4.4 Toward an Immature 4.2 Ecopath Model for a Large Chinese but Stable Ecosystem 83 Lake: A Case Study 68 4.2.4.5 Potential Driving 4.2.1 Introduction 68 Factors and 4.2.2 Study Site 70 Underlying 4.2.3 Model Development 73 Mechanisms 84 4.2.3.1 Model Construction 4.2.4.6 Hints for Future Lake and Parameterization 73 Fishery and 4.2.3.2 Evaluation of Ecosystem Restoration 85 Functioning 74 4.2.3.3 Determination of 4.3 Conclusions 86 Trophic Level 76 References 86 4.2.4 Results and Discussion 76 4.2.4.1 Basic Model Performance 76 Ecological Model Types, Volume 28 Ó 2016 Elsevier B.V. http://dx.doi.org/10.1016/B978-0-444-63623-2.00004-9 65 All rights reserved. 66 4. STEADY STATE MODELS 4.1 STEADY STATE MODEL: ECOPATH AS AN EXAMPLE 4.1.1 Steady State Model Steady state ecological models are established to describe conditions in which the modeled components (mass or energy) are stable, i.e., do not change over time (Jørgensen and Fath, 2011).
    [Show full text]
  • Models for an Ecosystem Approach to Fisheries
    ISSN 0429-9345 FAO FISHERIES 477 TECHNICAL PAPER 477 Models for an ecosystem approach to fisheries Models for an ecosystem approach to fisheries This report reviews the methods available for assessing the impacts of interactions between species and fisheries and their implications for marine fisheries management. A brief description of the various modelling approaches currently in existence is provided, highlighting in particular features of these models that have general relevance to the field of ecosystem approach to fisheries (EAF). The report concentrates on the currently available models representative of general types such as bionergetic models, predator-prey models and minimally realistic models. Short descriptions are given of model parameters, assumptions and data requirements. Some of the advantages, disadvantages and limitations of each of the approaches in addressing questions pertaining to EAF are discussed. The report concludes with some recommendations for moving forward in the development of multispecies and ecosystem models and for the prudent use of the currently available models as tools for provision of scientific information on fisheries in an ecosystem context. FAO Cover: Illustration by Elda Longo FAO FISHERIES Models for an ecosystem TECHNICAL PAPER approach to fisheries 477 by Éva E. Plagányi University of Cape Town South Africa FOOD AND AGRICULTURE AND ORGANIZATION OF THE UNITED NATIONS Rome, 2007 The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.
    [Show full text]