Characteristics, Main Impacts, and Stewardship of Natural and Artificial Freshwater Environments: Consequences for Biodiversity Conservation
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water Review Characteristics, Main Impacts, and Stewardship of Natural and Artificial Freshwater Environments: Consequences for Biodiversity Conservation Marco Cantonati 1,2,* , Sandra Poikane 3, Catherine M. Pringle 4, Lawrence E. Stevens 5, Eren Turak 6,7 , Jani Heino 8, John S. Richardson 9 , Rossano Bolpagni 10 , Alex Borrini 1, Núria Cid 11, Martina Ctvrtlˇ íková 12, Diana M. P. Galassi 13 , Michal Hájek 14 , Ian Hawes 15 , Zlatko Levkov 16, Luigi Naselli-Flores 17 , Abdullah A. Saber 1,18 , Mattia Di Cicco 13, Barbara Fiasca 13, Paul B. Hamilton 19, Jan Kubeˇcka 12 , Stefano Segadelli 20 and Petr Znachor 12 1 MUSE—Museo delle Scienze, Limnology and Phycology Section, Corso del Lavoro e della Scienza 3, 38123 Trento, Italy; [email protected] (A.B.); [email protected] (A.A.S.) 2 Patrick Center for Environmental Research, Academy of Natural Sciences of Drexel University, Philadelphia, PA 19103, USA 3 European Commission, Joint Research Centre (JRC), 21027 Ispra, Italy; [email protected] 4 Odum School of Ecology, The University of Georgia, Athens, GA 30602-2602, USA; [email protected] 5 Museum of Northern Arizona Springs Stewardship Institute, 3101 N Ft Valley Rd, Flagstaff, AZ 86001, USA; [email protected] 6 NSW Department of Planning, Industry and the Environment, 10 Valentine Ave, Parramatta, NSW 2150, Australia; [email protected] 7 Palaeontology, Geobiology and Earth Archives Research Centre (PANGEA), School of Biological, Earth and Environmental Sciences UNSW, Kensington 2052, Australia 8 Finnish Environment Institute, Freshwater Centre, Paavo Havaksen Tie 3, FI-90570 Oulu, Finland; [email protected] 9 Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; [email protected] 10 Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; [email protected] 11 INRAE, UR RiverLy, centre de Lyon-Villeurbanne, 5 rue de la Doua CS70077, 69626 Villeurbanne CEDEX, France; [email protected] 12 Czech Academy of Sciences, Biology Centre, Institute of Hydrobiology, Na Sádkách 7, 370 05 Ceskˇ é Budˇejovice,Czech Republic; [email protected] (M.C.);ˇ [email protected] (J.K.); [email protected] (P.Z.) 13 Department of Life, Health and Environmental Sciences, University of L’Aquila, 67100 L’Aquila, Italy; [email protected] (D.M.P.G.); [email protected] (M.D.C.); barbara.fi[email protected] (B.F.) 14 Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotláˇrská 2, 61137 Brno, Czech Republic; [email protected] 15 Coastal Marine Field Station, University of Waikato, Tauranga 3110, New Zealand; [email protected] 16 Institute of Biology, Faculty of Natural Sciences, Ss. Cyril and Methodius University, Skopje 1000, North Macedonia; [email protected] 17 Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90123 Palermo, Italy; [email protected] 18 Botany Department, Faculty of Science, Ain Shams University, Abbassia Square, 11566 Cairo, Egypt 19 Phycology Section, Research and Collections Division, Canadian Museum of Nature, Ottawa, ON K1P6P4, Canada; [email protected] 20 Servizio Geologico, Sismico e dei Suoli, Regione Emilia-Romagna, Viale della Fiera 8, 40127 Bologna, Italy; [email protected] * Correspondence: [email protected]; Tel.: +39-0461-270342 Received: 26 November 2019; Accepted: 9 January 2020; Published: 16 January 2020 Water 2020, 12, 260; doi:10.3390/w12010260 www.mdpi.com/journal/water Water 2020, 12, 260 2 of 85 Abstract: In this overview (introductory article to a special issue including 14 papers), we consider all main types of natural and artificial inland freshwater habitas (fwh). For each type, we identify the main biodiversity patterns and ecological features, human impacts on the system and environmental issues, and discuss ways to use this information to improve stewardship. Examples of selected key biodiversity/ecological features (habitat type): narrow endemics, sensitive (groundwater and GDEs); crenobionts, LIHRes (springs); unidirectional flow, nutrient spiraling (streams); naturally turbid, floodplains, large-bodied species (large rivers); depth-variation in benthic communities (lakes); endemism and diversity (ancient lakes); threatened, sensitive species (oxbow lakes, SWE); diverse, reduced littoral (reservoirs); cold-adapted species (Boreal and Arctic fwh); endemism, depauperate (Antarctic fwh); flood pulse, intermittent wetlands, biggest river basins (tropical fwh); variable hydrologic regime—periods of drying, flash floods (arid-climate fwh). Selected impacts: eutrophication and other pollution, hydrologic modifications, overexploitation, habitat destruction, invasive species, salinization. Climate change is a threat multiplier, and it is important to quantify resistance, resilience, and recovery to assess the strategic role of the different types of freshwater ecosystems and their value for biodiversity conservation. Effective conservation solutions are dependent on an understanding of connectivity between different freshwater ecosystems (including related terrestrial, coastal and marine systems). Keywords: freshwater; habitat; biodiversity; ecosystem; impact; conservation; stewardship; foundation species; least-impaired habitat relicts 1. Introduction Global climate change now threatens all ecosystems on Earth and the species they support, and the services and resources they provide to humans [1]. Freshwater is a precious resource and its future, along with that of the species and ecosystems it supports (almost 7% of global biodiversity in spite of freshwaters being tiny in their areal extent and relative volume [2]) is uncertain. Freshwater ecosystems are among the most endangered. Threats from climate change, contamination, water harvesting, impoundment, and other stressors are widespread, and no freshwater ecosystem is secure in the face of these threats [3]. Springs have been usurped for human consumption globally, and lakes in alpine, Arctic, and boreal areas are impacted by climate warming and airborne pollutants (e.g., [4]). De Graaf et al. (2019) [5] estimate that two-thirds of the world’s developed watersheds will reach environmental flow limits due to groundwater pumping by 2050. These impacts on freshwater ecosystems call for improved understanding of these threats, how they affect biodiversity, and how to counter them. Among the key knowledge gaps are accurate and precise global lists of freshwater-dependent species. Only relatively recently have major steps been taken towards compiling such lists [6]. Addressing such gaps will bring us closer to solving these challenges to sustainable freshwater ecosystem stewardship. Each of the papers in this Virtual Special Issue (VSI) addresses knowledge gaps, with most papers focused on an individual major ecosystem type. All kingdoms of life are found in freshwaters. At least 126,000 animal species may be dependent on freshwater ecosystems [6]. Many groups of freshwater organisms are still poorly known, particularly microbes and protists. As advocated for cyanobacteria [7], a polyphasic approach integrating information gained from morphology, molecular phylogeny, bioorganic chemistry (e.g., [8]), and ecology should be applied whenever possible to the taxonomy of freshwater taxa. Organisms do not occur in isolation outside of a biotic assemblage and ecosystem, and individual species cannot be protected unless whole systems are conserved (e.g., [9]). Some recent global initiatives have focused on this issue. For example, the Red List of Ecosystems of IUCN [10] provides a “Collapse” (CO) category, the analog of the extinct (EX) category for species proposed by IUCN [11]. The only ecosystem classified in this way was a freshwater ecosystem, the Aral Sea. A severe reduction in freshwater Water 2020, 12, 260 3 of 85 biodiversity there by 2050 was predicted more than 15 years ago [12]. However, there is a general bias towards terrestrial conservation in general biodiversity assessment, and a plea was recently published to include freshwater species [13]. To counter negative trends, the Alliance for Freshwater Life was recently launched [14] as a global, united call to protect freshwater biodiversity. This conservation expert network aims to provide the critical mass for effective representation of freshwater biodiversity, to develop solutions balancing the needs of development and conservation, and to more effectively communicate the important role of freshwater ecosystems. Continental aquatic ecosystems are among the most threatened and altered natural systems. Commonly, water is considered a free resource, and wetlands are perceived by people as wastelands that should be transformed into “useful” systems [15]. Considering coastal and inland waters, there is a continuous loss of natural wetlands and a continuous increase in man-made wetlands [16]. A review by Davidson (2014) [17] showed that the reported long-term loss of natural wetlands averages between 54%–57%, but the loss may have been as high as 87% since the 18th Century. Moreover, the author notes the lack of sufficient data to obtain a comprehensive overview of changes in wetland areas worldwide, particularly for Africa, Neotropics, and Oceania. Data are missing, especially for temporal trends, and also for some of the world’s major flooded forest areas such as those