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He F, Svenning JC, Chen X, Tockner K, Kuemmerle T, le Roux E, Moleón M, Gessner J, Jähnig SC. Freshwater megafauna shape ecosystems and facilitate restoration. Biol Rev Camb Philos Soc 2024; 99:1141-1163. [PMID: 38411930 DOI: 10.1111/brv.13062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 02/28/2024]
Abstract
Freshwater megafauna, such as sturgeons, giant catfishes, river dolphins, hippopotami, crocodylians, large turtles, and giant salamanders, have experienced severe population declines and range contractions worldwide. Although there is an increasing number of studies investigating the causes of megafauna losses in fresh waters, little attention has been paid to synthesising the impacts of megafauna on the abiotic environment and other organisms in freshwater ecosystems, and hence the consequences of losing these species. This limited understanding may impede the development of policies and actions for their conservation and restoration. In this review, we synthesise how megafauna shape ecological processes in freshwater ecosystems and discuss their potential for enhancing ecosystem restoration. Through activities such as movement, burrowing, and dam and nest building, megafauna have a profound influence on the extent of water bodies, flow dynamics, and the physical structure of shorelines and substrata, increasing habitat heterogeneity. They enhance nutrient cycling within fresh waters, and cross-ecosystem flows of material, through foraging and reproduction activities. Freshwater megafauna are highly connected to other freshwater organisms via direct consumption of species at different trophic levels, indirect trophic cascades, and through their influence on habitat structure. The literature documenting the ecological impacts of freshwater megafauna is not evenly distributed among species, regions, and types of ecological impacts, with a lack of quantitative evidence for large fish, crocodylians, and turtles in the Global South and their impacts on nutrient flows and food-web structure. In addition, population decline, range contraction, and the loss of large individuals have reduced the extent and magnitude of megafaunal impacts in freshwater ecosystems, rendering a posteriori evaluation more difficult. We propose that reinstating freshwater megafauna populations holds the potential for restoring key ecological processes such as disturbances, trophic cascades, and species dispersal, which will, in turn, promote overall biodiversity and enhance nature's contributions to people. Challenges for restoration actions include the shifting baseline syndrome, potential human-megafauna competition for habitats and resources, damage to property, and risk to human life. The current lack of historical baselines for natural distributions and population sizes of freshwater megafauna, their life history, trophic interactions with other freshwater species, and interactions with humans necessitates further investigation. Addressing these knowledge gaps will improve our understanding of the ecological roles of freshwater megafauna and support their full potential for facilitating the development of effective conservation and restoration strategies to achieve the coexistence of humans and megafauna.
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Affiliation(s)
- Fengzhi He
- Key Laboratory of Wetland Ecology and Environment, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Shengbei Street 4888, Changchun, 130102, China
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin, 12587, Germany
- Geography Department, Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany
- Center for Ecological Dynamics in a Novel Biosphere (ECONOVO) and Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Department of Biology, Aarhus University, Ny Munkegade 114, Aarhus, 8000, Denmark
| | - Jens-Christian Svenning
- Center for Ecological Dynamics in a Novel Biosphere (ECONOVO) and Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Department of Biology, Aarhus University, Ny Munkegade 114, Aarhus, 8000, Denmark
| | - Xing Chen
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin, 12587, Germany
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Str. 1-3, Berlin, 14195, Germany
| | - Klement Tockner
- Senckenberg Society for Nature Research, Senckenberganlage 25, Frankfurt am Main, 60325, Germany
- Faculty for Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Straße 9, Frankfurt am Main, 60438, Germany
| | - Tobias Kuemmerle
- Geography Department, Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany
| | - Elizabeth le Roux
- Center for Ecological Dynamics in a Novel Biosphere (ECONOVO) and Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Department of Biology, Aarhus University, Ny Munkegade 114, Aarhus, 8000, Denmark
| | - Marcos Moleón
- Department of Zoology, University of Granada, Avenida de Fuente Nueva S/N, Granada, 18071, Spain
| | - Jörn Gessner
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin, 12587, Germany
| | - Sonja C Jähnig
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin, 12587, Germany
- Geography Department, Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany
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Targino FJ, Ribeiro JDDN, Simões JS, Carneiro CS, Lazzarini SM, Souza AR, Ferreira MDS, Mano SB, Mársico ET. Total Mercury Content in the Tissues of Freshwater Chelonium ( Podocnemis expansa) and a Human Health Risk Assessment for the Amazon Population in Brazil. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6489. [PMID: 37569029 PMCID: PMC10418661 DOI: 10.3390/ijerph20156489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/21/2023] [Accepted: 06/29/2023] [Indexed: 08/13/2023]
Abstract
Researchers recognize the silent, negative and deleterious effects caused by mercury pollution in gold mining areas. Freshwater turtles are culturally part of the diet of riverside populations in the Amazon region and this area presents mercury (Hg) pollution issues mainly due to gold mining activities. Thus, this research aimed to evaluate the total mercury (THg) content in the different organs of Amazonian giant river turtle (Podocnemis expansa) and carry out a human health risk assessment associated with the consumption of these animals. This study was conducted in the Vila Balbina, municipality of Presidente Figueiredo, state of Amazonas, Brazil. Skin (n = 28), muscle (n = 19) and brain (n = 2) samples were analyzed by Atomic Absorption Spectrometry (TDA-AAS) and a DMA-80™ mercury analyzer was used for the total mercury determinations. The average values found for THg in the skin, muscle and brain samples were, respectively, 0.1045 mg·kg-1, 0.1092 mg·kg-1 and 0.0601 mg·kg-1. Thus, THg was observed even though the P. expansa were kept in captivity, possibly due to previous contamination by air, water and food. The Hazard Quotient (HQ) was calculated considering a 9.07 g·day-1 intake dose of P. expansa and the consumption of turtles once a week showed an HQ = 2.45, which may cause long-term injuries to human health. Although the muscle concentrations were below the maximum limit established by the World Health Organization (WHO) and Brazilian regulatory agencies, it is important to evaluate consumption factors such as amount ingested, frequency and animal gender, which may cause a potential risk to regular consumers due to mercury bioaccumulation. The WHO may consider various aspects in order to warn the Amazon population about the severity and silent hazard of this metal, especially due to the importance of this matrix in the region. This region urgently needs government actions to inhibit clandestine mining and to prevent future serious, chronic health problems of the entire population.
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Affiliation(s)
- Fábio Júnior Targino
- Faculty of Veterinary, Universidade Federal Fluminense (UFF), Niterói 24230-321, Brazil; (F.J.T.); (J.D.d.N.R.); (J.S.S.); (M.d.S.F.); (S.B.M.)
| | - Joanna Damazio de Nunes Ribeiro
- Faculty of Veterinary, Universidade Federal Fluminense (UFF), Niterói 24230-321, Brazil; (F.J.T.); (J.D.d.N.R.); (J.S.S.); (M.d.S.F.); (S.B.M.)
| | - Julia Siqueira Simões
- Faculty of Veterinary, Universidade Federal Fluminense (UFF), Niterói 24230-321, Brazil; (F.J.T.); (J.D.d.N.R.); (J.S.S.); (M.d.S.F.); (S.B.M.)
| | - Carla Silva Carneiro
- Faculty of Pharmacy, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-580, Brazil;
| | - Stella Maris Lazzarini
- Centro de Pesquisa e Preservação de Mamíferos Aquáticos (CPPMA), Eletronorte, Presidente Figueiredo 69736-000, Brazil; (S.M.L.); (A.R.S.)
| | - Aline Ramos Souza
- Centro de Pesquisa e Preservação de Mamíferos Aquáticos (CPPMA), Eletronorte, Presidente Figueiredo 69736-000, Brazil; (S.M.L.); (A.R.S.)
- Institute of Biological Sciences, Universidade Federal do Amazonas (UFAM), Manaus 69077-000, Brazil
| | - Micheli da Silva Ferreira
- Faculty of Veterinary, Universidade Federal Fluminense (UFF), Niterói 24230-321, Brazil; (F.J.T.); (J.D.d.N.R.); (J.S.S.); (M.d.S.F.); (S.B.M.)
| | - Sergio Borges Mano
- Faculty of Veterinary, Universidade Federal Fluminense (UFF), Niterói 24230-321, Brazil; (F.J.T.); (J.D.d.N.R.); (J.S.S.); (M.d.S.F.); (S.B.M.)
| | - Eliane Teixeira Mársico
- Faculty of Veterinary, Universidade Federal Fluminense (UFF), Niterói 24230-321, Brazil; (F.J.T.); (J.D.d.N.R.); (J.S.S.); (M.d.S.F.); (S.B.M.)
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McCoy CJ, Flores-Villela OA, Vogt RC, Pappas M, McCoy JK. Ecology of Riverine Turtle Communities in the Southern United States: Food Resource Use and Trophic Niche Dimensions. CHELONIAN CONSERVATION AND BIOLOGY 2020. [DOI: 10.2744/ccb-1447.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- C. J. McCoy
- Deceased, formerly Curator of Amphibians and Reptiles, Carnegie Museum of Natural History, 4400 Forbes Avenue, Pittsburgh, Pennsylvania 15206 USA
| | - Oscar A. Flores-Villela
- Museo de Zoologia Facultade de Ciencias, Universidad Nacional Autónoma de Mexico, Ciudad de Mexico, Mexico 04510 []
| | - Richard C. Vogt
- Coordinação de Biodiverside, Instituto Nacional de Pesquias da Amazonia, Avenida Andre Araujo 2936, Manaus, Amazonas, Brazil 69060–001 []
| | | | - J. Kelly McCoy
- Dean of Arts and Sciences, Crawford Wheatley Hall, Georgia Southwestern State University, Americus, Georgia 31709 USA []
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