J. David Allan Maria M. Castillo Krista A. Capps Stream Ecology Structure and Function of Running Waters Third Edition Stream Ecology J. David Allan (cid:129) María M. Castillo (cid:129) Krista A. Capps Stream Ecology Structure and Function of Running Waters Third Edition 123 J.David Allan MaríaM.Castillo Schoolfor Environment Departamento deCiencias andSustainability dela Sustentabilidad, ElColegio University of Michigan dela FronteraSur AnnArbor, MI,USA Villahermosa, Tabasco,México Krista A.Capps OdumSchool ofEcology andthe Savannah RiverEcologyLaboratory University of Georgia,Athens, GA, USA ISBN978-3-030-61285-6 ISBN978-3-030-61286-3 (eBook) https://doi.org/10.1007/978-3-030-61286-3 1stedition:©J.DavidAllan1995 2ndedition:©Springer2007 3rdedition:©SpringerNatureSwitzerlandAG2021 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartofthematerialis concerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation,broadcasting,reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation,computersoftware,orbysimilarordissimilarmethodologynowknownorhereafterdeveloped. Theuseofgeneraldescriptivenames,registerednames,trademarks,servicemarks,etc.inthispublicationdoesnot imply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevantprotectivelawsand regulationsandthereforefreeforgeneraluse. Thepublisher,theauthorsandtheeditorsaresafetoassumethattheadviceandinformationinthisbookarebelieved tobetrueandaccurateatthedateofpublication.Neitherthepublishernortheauthorsortheeditorsgiveawarranty, expressedorimplied,withrespecttothematerialcontainedhereinorforanyerrorsoromissionsthatmayhavebeen made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Coverphoto:StudentsconductingmacroinvertebratesamplingintheGuareRiver,Venezuela ThisSpringerimprintispublishedbytheregisteredcompanySpringerNatureSwitzerlandAG Theregisteredcompanyaddressis:Gewerbestrasse11,6330Cham,Switzerland Dedicated to our families, and to colleagues, students, and all those whose efforts advance our understanding of flowing waters to protect them for future generations Preface to the Third Edition The underlying science of stream ecology has undergone dramatic advances since the first edition over 20 years ago. The subject matter of other disciplines increasingly must be addressed, including hydrology, geomorphology, an array of topics in the earth sciences and biogeochemistry, along with advances in socioeconomic studies. The published literature is enormous, spread across many different professional journals. We cannot do justice to all oftheseadvances,buthopefully,wehaveprovidedanentrypointforreadersnewtothefield. Some of the material will be challenging to some readers, depending on background. Each chapterhasasummarythatclarifiesthemainideascovered,anditmaybehelpfultoviewthat first, to keep the main ideas in focus. This Third Edition of Stream Ecology will be used primarily in electronic form, as an e-book, and viewers will have the opportunity to acquire individual chapters rather than the entire book. Recognizing that readers may not have the opportunity to refer back and forth amongdifferentchapters,wehavemadeanefforttoensurethateachchaptercanstandalone. The result is a moderate amount of repetition, which we hope will serve either as a useful explanation or reminder, ensuring that each chapter’s narrative is accessible without depending upon significant cross-referencing to other chapters. We are grateful to many individuals who have discussed ideas and shared references with us in preparation of this Third Edition of Stream Ecology. We especially thank a number of colleagueswhoreadandimprovedearlierversionsofchapters,includingSebastianBirk,Alex Flecker, Hal Halvorson, Nick Hudson, Susan Jackson, Peter McIntyre, Thomas Parr, LeRoy Poff, Amber Ulseth, and Ellen Wohl. We also appreciate the generosity of colleagues who shared or helped us acquire photographs, including Francesco Comiti, Carolyn Cummins, ChrisDutton,JeffDuda,JohnGussman,AngusMcIntosh,JeremyMonroe,LucaMessina,Jim O’Connor,JulianOlden,AmandaSubalusky,and JohnWarrick.Weareespeciallygratefulto Jesús Montoya for his excellent work in figure preparation. We appreciate the support of our editors Judith Terpos and Nel van der Werf during the preparation of this edition, and the efficient work of their production team. Although the material in this third edition is substantially modified and updated, it nonetheless includes material from previous editions. We acknowledge our debt to many wonderfulcolleagues,whoprovidedhelpfulguidancetopreviouseditionsofStreamEcology. Ann Arbor, USA J. David Allan Villahermosa, México María M. Castillo Athens, USA Krista A. Capps vii Preface to the Second Edition The diversity of running water environments is enormous. When one considers torrential mountain brooks, large rivers of lowlands, and great rivers whose basins occupy subconti- nents, it is apparent how location-specific environmental factors contribute to the sense of uniqueness and diversity of running waters. At the same time, however, our improved understanding of ecological, biogeochemical, hydrological, and geomorphological processes providesinsightintothestructuralandfunctionalcharacteristicsofriversystemsthatbringsa unifying framework tothis field of study. Inputs and transformations of energy and materials are important in all river systems, regional species richness and local species interactions influence the structure of all riverine communities, and the interaction of physical and bio- logicalforcesisimportanttovirtuallyeveryquestionthatisasked.Itseemsthattheprocesses acting in running waters are general, but the settings often are unique. Webelievethatithelpsthereader,whensomepatternorresultisdescribed,tohavesome image of what kind of stream or river is under investigation, and also where it is located. Streamecology,likeallecology,dependsgreatlyoncontext:place,environmentalconditions, season, species. The text includes frequent use of descriptors like “small woodland stream”, “openpasturelandstream”,or“largelowlandriver”,andwebelievethatreaderswillfindthese useful clues to the patterns and processes that are reported. For most studies within North America we have included further regional description, but have done so less frequently for studies from elsewhere around the globe. We apologize to our international readers for this pragmatic choice, and we have made every effort to include examples and literature from outside of North America. Somelocationshaveestablishedthemselvesasleadingcentersofstudyduetotheworkof many researchers carried out over decades. The Hubbard Brook Experimental Forest in New Hampshire, Coweeta Hydrologic Laboratory in North Carolina, and some individual streams including Walker Branch in Tennessee, Sycamore Creek in Arizona, Río Las Marías in Venezuela, and the Taieri and Whatawhata in New Zealand, are locations that appear fre- quently in the pages that follow. Knowing what these places are like, and how they may or maynotbetypical,inourviewjustifiesthefrequentuseofplacenamesandbriefdescriptions. Thenamesoforganismsalsoappearfrequentlyandmayatfirstoverwhelmthereader.Itmay be easiest to pay them little attention until they gradually become familiar. Ultimately it is difficult to really comprehend the outcome of a study without some appreciation for the organisms that were present. Asistrueforeveryareaofecologyinpresenttime,thestudyofstreamsandriverscannot be addressed exclusive of the role of human activities, nor can we ignore the urgency of the need for conservation. This is a two-way street. Ecologists who study streams without con- sidering how past or present human modifications of the stream or its valley might have contributed to their observations do so at the risk of incomplete understanding. Conservation efforts that lack an adequate scientific basis are less likely to succeed. One trend that seems safe to forecast in stream ecology is toward a greater emphasis on understanding human impacts. Fortunately, signs of this trend are already apparent. ix x PrefacetotheSecondEdition Wehaveorganizedtheflowoftopicsinawaythatismostlogicaltous,butnodoubtsome readerswillprefertocovertopicsinwhateverordertheyfindmostuseful.Forthisreason,we havestrivedtoexplainenoughineachchapterthatitiscomprehensibleonitsown.Thisleads to a certain amount of intentional repetition, which we hope will provide clarification or a reminder that will benefit the reader’s understanding. We are extremely grateful to the many colleagues who shared ideas, provided references, andreviewedchaptersindraftform.Spacedoesn’tpermitustothankeveryonewhoanswered aquerywithahelpfulexplanationandsuggestionsforsourcematerial;howeverwedowishto acknowledge the individuals who carefully read and improved our chapters. Any remaining shortcomings or errors are the authors’ responsibility, but hopefully these are few, thanks to the efforts of: Robin Abell, Brian Allan, Fred Benfield, Barb Downes, David Dudgeon, Kurt Fausch, Stuart Findlay, Alex Flecker, Art Gold, Sujay Kaushal, Matt Kondolf, Angus McIntosh, Peter McIntyre, Rich Merritt, Judy Meyer, Pat Mulholland, Bobbi Peckarsky, LeRoyPoff,BrianRoberts,DougShields,AlSteinman,JanStevenson,JenTank,PaulWebb, Jack Webster, Kevin Wehrly, and Kirk Winemiller. All were generous with their time and their knowledge, and we are in their debt. Wealsowishtothankthosewhoprovidedhelpfulreviewsofchaptersinthefirsteditionof thisbook,includingFredBenfield,ArtBenke,ArtBrown,ScottCooper,StuartFindlay,Alex Flecker, Nancy Grimm, David Hart, Chuck Hawkins, Bob Hughes, Steve Kohler, Gary Lamberti,RexLowe,RichMerritt,DianeMcKnight,JudyMeyer,BobbiPeckarsky,PeteOde, Walt Osterkamp, M.L. Ostrofsky, Margaret Palmer, LeRoy Poff, Karen Prestergaard, Ike Schlosser, Len Smock, Al Steinman, Scott Wissinger, and Jack Webster. Other individuals provided invaluable assistance with important aspects of manuscript production. Mary Henja and Jamie Steffes did extensive proof reading and arranged all the figure permissions. Haymara Alvarez, Susana Martinez and Dana Infante assisted with pro- duction of figures, and Jesus Montoya did a superb job of taking figures made in many different styles and re-drafting them to a common style and high quality. Funding for MMC release time and travel to Michigan was provided by Dirección de Desarrollo Profesoral of Universidad Simon Bolivar, and the Horace H Rackham School of Graduate Studies of the UniversityofMichigan.WealsowishtothankoureditorsatSpringer,SuzanneMekkingand Martine van Bezooijen, and our prior editor Anna Besse-Lototskaya, for their support, encouragement, and patience. It has been a pleasure to work with them all. Lastly,ourdeepestthanksgotoourfamiliesfortheirloveandsupport,andwemustadmit for agooddealoftolerance aswell,duringthewriting ofthisbook.It hasbeenanenjoyable experienceforbothofus,andwehopethatthecurrenteditionwillserveasausefulguidefor the next generation of stream ecologists. Contents 1 Rivers in the Anthropocene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Structure and Function of River Systems. . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 Physical Setting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.2 The Fluvial Ecosystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1.3 Vision of a Healthy River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Rivers in the Anthropocene. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2.1 State of the world’s River Systems. . . . . . . . . . . . . . . . . . . . . . . 7 1.2.2 What is at Stake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.2.3 What is to Be Done? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.3 What to Expect in This Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2 Streamflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.1 The Water Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.1.1 Global Water Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.1.2 Water Balance of a Catchment . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.1.3 Surface Versus Groundwater Pathways . . . . . . . . . . . . . . . . . . . . 21 2.2 Streamflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2.2.1 The Hydrograph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2.3 Flow Variation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 2.3.1 The Likelihood of Extreme Events . . . . . . . . . . . . . . . . . . . . . . . 27 2.3.2 Ecologically Relevant Flow Metrics . . . . . . . . . . . . . . . . . . . . . . 28 2.3.3 Hydrologic Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2.4 Human Influence on Streamflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2.4.1 Dams and Impoundments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2.4.2 Effect of Land Use on Streamflow . . . . . . . . . . . . . . . . . . . . . . . 34 2.4.3 Effect of Climate Change on Streamflow. . . . . . . . . . . . . . . . . . . 36 2.5 Environmental Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 2.6 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 3 Fluvial Geomorphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 3.1 Geomorphological Features of a River System. . . . . . . . . . . . . . . . . . . . . 45 3.1.1 The Drainage Network. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 3.1.2 The Stream Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 3.1.3 Hydraulic Geometry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 3.1.4 Channel Pattern. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 3.1.5 Pool-Riffle Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 3.1.6 The Floodplain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 xi xii Contents 3.2 Sediments and Their Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 3.2.1 Bed Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 3.2.2 Bank and Bed Erosion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 3.2.3 Particle Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 3.2.4 Sediment Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 3.2.5 Factors Influencing Sediment Concentrations and Loads . . . . . . . 56 3.3 Fluvial Processes Along the River Continuum . . . . . . . . . . . . . . . . . . . . . 59 3.3.1 Fluvial Processes and Channel Morphologies . . . . . . . . . . . . . . . 60 3.3.2 Channel Dynamics Over Long Timeframes. . . . . . . . . . . . . . . . . 62 3.3.3 Channel Classifications and Their Uses. . . . . . . . . . . . . . . . . . . . 62 3.4 Applications of Fluvial Geomorphology . . . . . . . . . . . . . . . . . . . . . . . . . 63 3.4.1 Dams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 3.4.2 Gravel Mining. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 3.4.3 River Restoration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 3.5 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 4 Streamwater Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 4.1 Dissolved Gases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 4.2 Major Dissolved Constituents of River Water . . . . . . . . . . . . . . . . . . . . . 78 4.2.1 Variability in Ionic Concentrations . . . . . . . . . . . . . . . . . . . . . . . 80 4.2.2 The Dissolved Load. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 4.2.3 Chemical Classification of River Water. . . . . . . . . . . . . . . . . . . . 84 4.3 The Bicarbonate Buffer System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 4.4 Biological Implications of Varying Ionic Concentrations . . . . . . . . . . . . . 86 4.4.1 Variation in Ionic Concentration. . . . . . . . . . . . . . . . . . . . . . . . . 86 4.4.2 Salinization and Alkalinization of Freshwater Systems. . . . . . . . . 87 4.4.3 Effects of Acidity on Stream Ecosystems . . . . . . . . . . . . . . . . . . 90 4.5 Legacy and Emerging Chemical Contaminants. . . . . . . . . . . . . . . . . . . . . 92 4.5.1 Legacy Contaminants in Rivers and Streams. . . . . . . . . . . . . . . . 93 4.5.2 Emerging Contaminants in Running Waters . . . . . . . . . . . . . . . . 93 4.6 Plastic Pollution in Freshwater Systems. . . . . . . . . . . . . . . . . . . . . . . . . . 96 4.7 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 5 The Abiotic Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 5.1 The Flow Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 5.1.1 Characterizing the Flow Environment . . . . . . . . . . . . . . . . . . . . . 104 5.1.2 Flows at the Scale of Organisms. . . . . . . . . . . . . . . . . . . . . . . . . 105 5.1.3 Influence of Extreme Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 5.1.4 Flow Management Applications . . . . . . . . . . . . . . . . . . . . . . . . . 111 5.2 Physical Habitat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 5.2.1 Inorganic Substrates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 5.2.2 Organic Substrates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 5.2.3 The Influence of Physical Habitat on Stream Assemblages. . . . . . 114 5.2.4 Physical Habitat Restoration. . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 5.3 Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 5.3.1 Shade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 5.3.2 Hydrologic Influences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 5.3.3 Urbanization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128