<p> 1 Supplementary materials</p><p>2</p><p>3 Appendix 1 Summary of the Hong Kong study streams; measures of elevation, slope and</p><p>4 riparian canopy cover are averaged across up- and downstream reaches.</p><p>5</p><p>6 Appendix 2 List of epibenthic algae (species for Bacillariophyta, and genera for</p><p>7 Chlorophyta, Cyanophyta, and Rhodophyta) and their relative abundance (+: less than 1%</p><p>8 and greater than 0; ++: less than 5% and greater than 1%; +++: greater than 5%) in 10 Hong</p><p>9 Kong streams during the wet and dry seasons.</p><p>10</p><p>11 Appendix 3 Genus-level composition of algal metrics (ecological guilds and diatom growth</p><p>12 forms) used to investigate responses to water extraction in Hong Kong streams.</p><p>13</p><p>14 1 Appendix 1 Summary of the Hong Kong study streams; measures of elevation, slope and</p><p>2 riparian canopy cover are averaged across up- and downstream reaches.</p><p>3</p><p>Canopy Stream Elevation Slope Stream Abbr. Location cover order (m) (%) (%) 22023' N Ha Fa Shan HFS 3 153 - 163 8.5 - 14 28 - 45 114006' E 22026' N Pak Sha O PSO 2 98 - 116 5.5 - 8 78 - 79 114º18' E 22026' N Hau Tong Kai HTK 4 76 - 140 8 - 13 8 - 38 114019' E 22024' N Tai Shui Hang TSH 3 114 - 143 9.5 - 14 14 - 23 114013' E 22023' N Chuen Lung lower CL 3 200 - 212 4.5 - 6.5 27 - 32 114006' E 22015' N Tung Chung TC 3 90 - 100 8.5 - 13 15 - 36 113056' E 22021' N Tai Lam Wu TLW 3 101 - 135 10 - 14.5 76 - 79 114014' E 22016' N Shek Mun Kap SMK 3 80 - 90 7.5 - 12 15- 60 113057' E 22025' N Tai Po Kau TPK 3 147 - 180 6.5 - 11.5 69 - 71 114010' E 22023' N Mui Tze Lam MTL 3 117 - 125 4.5 -7.5 74 - 88 114013' E 22015' N Wong Lung Hang WLH 3 103 - 177 11.5 - 12 21 - 38 113055' E 4</p><p>5 1 Appendix 2 List of epibenthic algae (species for Bacillariophyta, and genera for</p><p>2 Chlorophyta, Cyanophyta, and Rhodophyta) and their relative abundance (+: less than 1%; +</p><p>3 +: less than 5% and greater than 1%; +++: greater than 5%) in 10 Hong Kong streams during</p><p>4 the wet and dry seasons.</p><p>5</p><p>Taxa Wet Dry Bacillariophyta Achnanthes alpestris (Brun) Lange-Bertalot & Metzeltin + Achnanthes crenulata Grunow ++ ++ Achnanthes inflata (Kützing) Grunow + + Achnanthes lanceolata f. capitata (O.F.Müller) Hustedt + + Achnanthes microcephala Kützing Grunow + + Achnanthes taeniata Grunow + + Achnanthes sp. + + Achnanthidium brevipes (Agardh) Heiberg + + Achnanthidium exiguum (Grunow) Czarnecki + + Achnanthidium exile (Kützing) Round & Bukhtiyarova ++ ++ Achnanthidium minutissimum (Kützing) Czarnecki +++ +++ Adlafia aquaeductae (Krasske) Moser, Lange-Bertalot & Metzeltin + Adlafia bryophila (Petersen) Moser, Lange-Bertalot & Metzeltin + Amphipleura sp. + Anomoeoneis vitrea (Grunow) Ross + + Brachysira brebissonii Ross ++ ++ Brachysira serians (Brébisson) Round & Mann + + Caloneis alpestris (Grunow) Cleve + Cavinula lacustris (Gregory) Mann & Stickle + + Ceratoneis arcus (Ehrenberg) Kützing + Cocconeis krammeri Lange-Bertalot & Metzeltin + + Cocconeis placentula Ehrenberg +++ +++ Craticula halophila (Grunow) Mann + Cyclotella stelligera Cleve & Grunow + Cyclotella sp. + + Cymbella affinis Kützing + + Cymbella aspera (Ehrengerg) Cleve + + Cymbella cesatii (Rabenhorst) Grunow + Cymbella cymbiformis (Ehrenberg) Grunow ++ + Cymbella cymbiformis var. nonpunctata Fontell + Cymbella gracilis (Ehrenberg) Kützing + + Cymbella microcephala Grunow + Cymbella sinuata Gregory + + Taxa Wet Dry Cymbella tumida (Brébisson ex Kützing) van Heurck + Cymbella turgidula Grunow + Cymbella ventricosa var. lunata (Smith) Woodhead & Tweed + + Cymbopleura amphicephala (Naegeli) Krammer + Cymbopleura hustedtii (Krasske) Novelo, Tavera & Ibarra + + Delicata delicatula (Kützing) Krammer + + Diadesmis contenta (Grunow ex Van Heurck) Mann ++ + Diatoma vulgare Bory + Encyonema minutum (Hilse) Mann ++ ++ Encyonema ventricosum var. excisum (Kützing) Maye + Epithemia sp. + Eunotia arcus f. bidens (Grunow) Hustedt + Eunotia bactriana Ehrenberg + Eunotia camelus Ehrenberg + + Eunotia diodon Ehrenberg + + Eunotia flexuosa (Brébisson) Kützing + + Eunotia formica Ehrenberg + + Eunotia glacialis F. Meister + Eunotia lunaris (Ehrenberg) Grunow + + Eunotia minor (Kützing) Grunow + + Eunotia monodon var. tropica (Hustedt) Hustedt in Schmidt et al. + Eunotia nagelii Magula + + Eunotia pectinalis (Kützing) Rabenhorst + + Eunotia pectinalis var. recta Mayer ex Patrick + Eunotia quaternaria Ehrenberg + Eunotia rabenhorstiana (Grunow) Hustedt + + Eunotia robusta var. serra (Ehrenberg) Meister + Eunotia sarekensis var. bigibba (Kützing) Cleve-Euler + Eunotia tenella (Grunow) Hustedt + + Eunotia valida Hustedt + Eunotia sp. + + Fallacia lenzii (Hustedt) Lange-Bertalot + Fragilaria arcus (Kützing) Cleve + + Fragilaria capucina Desmazieres + Fragilaria capucina subsp. rumpens (Kützing) Lange-Bertalot + + Fragilaria crotonensis Kitton + Fragilaria sinuata Peragallo + Fragilaria tenera (Smith) Lange-Bertalot + Fragilaria ulna var. acus (Kützing) Lange-Bertalot + + Fragilaria vaucheria (Kützing) Peterson + Frustulia rhomboides (Ehrenberg) Pfitzer + + Gomphonema angustatum (Kützing) Rabenhorst + + Gomphonema augur var. sphaerophorum (Ehrenberg) Lange-Bertalot + + Taxa Wet Dry Gomphonema augur var. turris (Ehrenberg) Lange-Bertalot + + Gomphonema clevei Fricke +++ ++ Gomphonema constrictum var. clavata (Ehrenberg) Swirenko + Gomphonema constrictum var. truncatum (Ehrenberg) Gutwinski + Gomphonema gracile Ehrenberg + + Gomphonema hedinii Hustedt + + Gomphonema instablis Hohn & Hellerman + Gomphonema intricatum Kützing + + Gomphonema lanceolatum var. affine (Kützing) Cleve-Euler + Gomphonema manubrium Fricke + Gomphonema minusculum Krasske + Gomphonema montanum (Schumann) Grunow + + Gomphonema parvulum (Kützing) Kützing +++ +++ Gomphonema subclavatum var. commutatum (Grunow) Mayer + Gomphonema subtile (Ehrenberg) Tempère & Peragallo + + Gomphonema subtile var. sagitta (Schumann) Cleve + + Gyrosigma attenuatum (Kützing) Cleve + Halamphora normanii (Rabenhorst) Levkov + + Hantzschia amphioxys (Ehrenberg) Grunow + Hydrosera whampoensis (Schwartz) Deby + Karayevia carissima (Lange-Bertalot) Bukhtiyarova + Karayevia oblongella (Østrup) Aboal +++ +++ Kobayasia pseudosubtilissima (Manguin) Reichardt + + Kobayasia subtilissima (Cleve) Lange-Bertalot + + Luticola mutica (Kützing) Mann + Melosira sinensis Chen + + Melosira varians Agardh + + Navicula arvensis Hustedt + Navicula bisulcata var. undulata (Grunow) Prochazka + Navicula cari Ehrenberg + Navicula dicephala Ehrenberg + Navicula interrupta var. biceps (Gregory) Prochazka + Navicula lanceolata Ehrenberg + Navicula notha Wollace + + Navicula radiosa var. parva Wallace + Navicula radiosa var. tenella (Brébisson) Van Heurck + + Navicula subtilissima var. paucistriata Chen et Zhu + + Navicula trigonocephala (Ehrenberg) Ralfs + Navicula umbra Hohn & Hellerman + + Navicula viridula var. rostellata (Kützing) Cleve + + Navicula virihensis Cleve-Euler + Navicula sp. + + Naviculadicta absoluta (Hustedt) Lange-Bertalot + Taxa Wet Dry Naviculadicta ventraloconfusa var. chilensis (Krasske) Lange - Bertalot + Nitzschia acula Hantzsch ex Cleve & Grunow + + Nitzschia dissipata (Kützing) Grunow + + Nitzschia fonticola Grunow + + Nitzschia frustulum (Kützing) Grunow + + Nitzschia frustulum var. hantzschiana (Rabenhorst) Comber + Nitzschia gracilis Hantzsch + Nitzschia obtusa var. scalpelliformis (Grunow) Grunow + + Nitzschia paleacea Grunow + Nitzschia sinuata var. tabellaria (Grunow) Grunow + + Nupela impexiformis (Lange-Bertalot) Lange-Bertalot + Parlibellus protracta (Grunow) Witkowski, Lange-Bert. & Metzeltin + + Pinnularia gentilis (Donkin) Cleve + Pinnularia mesolepta (Ehrenberg) Smith + Pinnularia molaris (Grunow) Cleve + Pinnularia termitina (Ehrenberg) Patrick + Pinnularia sp. + + Planothidium delicatulum (Kützing) Round & Bukhtiyarova + + Planothidium lanceolatum (Brébisson ex Kützing) Lange-Bertalot + + Planothidium lanceolatum f. ventricosa (Hustedt) Bukhtiyarova + + Planothidium rostratum (Østrup) Lange-Bertalot ++ ++ Psammothidium hustedtii (Krasske) Mayama ++ + Psammothidium montanum (Krasske) Mayama ++ ++ Schizonema cryptocephalum (Kützing) Kuntze + + Schizonema radiosum (Kützing) Kuntze ++ + Schizonema rhynchocephala (Kützing) Kuntze + Sellaphora bacillum (Ehrenberg) Mann + + Sellaphora disjuncta (Hustedt) Mann + Sellaphora pupula (Kützing) Mereschkowsky + + Stauroneis kriegeri Patrick + + Suriraya linearis (Smith) Pfitzer + + Suriraya ovalis var. angusta (Kützing) Gutwinski + Surirella robusta Ehrenberg + + Surirella sp. + + Synedra fasciculata (Agardh) Kützing + Synedra ulna (Nitzsch) Ehrenberg ++ + Synedra sp. + Tabellaria fenestrata (Lyngbye) Kützing + + Tabellaria flocculosa (Roth) Kützing + Tabularia fasciculata (Agardh) Williams & Round + Tibiella brasiliensis (Grunow) Patrick + + Taxa Wet Dry Chlorophyta Bulbochaete Agardh + + Chaetophora Schrank + + Characium Brann + Chlorella Beijierinck + Cladophora Kützing + Cosmarium Corda ex Ralfs + + Geminella (Turp) Lagerheim + Gonatozygon De Bary + Oedogonium Link ex Hirn + + Oocystis Braun + Pediastrum Meyen + Penium Brebinsson + + Pleurotaenium Nägeli + Scenedesmus Mey + Spirogyra Link + + Stigeoclonium Kützing + Ulothrix Kützing + +</p><p>Cyanophyta Anabaena Bory + Calothrix Agardh + + Chamaesiphon Braun et Grunow + ++ Chroococcus ( Nägeli) Elekin + + Dichothrix Zanard + Gloeocapsa Kützing + + Homoeothrix Kirchner + ++ Lyngbya Agardh + + Merismopedia Mey + + Myxosarcina Printz + + Oscillatoria princeps Vaucher + Oscillatoria Vauch + ++ Pleurocapsa Thuret + Scytonema Agardh + Spirulina Turp + Stichosiphon Geitler + + Stigonema Agardh +</p><p>Rhodophyta Audouinella Bory + + Batrachospermum Roth + 1 1 1 Appendix 3 Genus-level composition of algal metrics (ecological guilds and diatom growth </p><p>2 forms) used to investigate responses to water extraction in Hong Kong streams.</p><p>3</p><p>Algal metrics Taxa composition Ecological guilds High-profile Bacillariophyta: Diadesmis, Diatoma, Eunotia, Fragilaria, </p><p>Gomphonema, Melosira, Synedra, Tabellaria, Tabularia</p><p>Chlorophyta: Bulbochaete, Gonatozygon, Oedogonium, </p><p>Pleurotaenium, Spirogyra, Stigeoclonium, Ulothrix</p><p>Cyanophyta: Anabaena, Calothrix, Chamaesiphon, </p><p>Dichothrix, Homoeothrix, Lyngbya, Oscillatoria, Scytonema,</p><p>Spirulina, Stichosiphon, Stigonema</p><p>Rhodophyta: Audouinella, Batrachospermum</p><p>Low-profile Bacillariophyta: Achnanthes, Achnanthidium, Amphipleura,</p><p>Amphora, Brachysira, Cocconeis, Cyclotella, Cymbella, </p><p>Cymbopleura, Delicata, Encyonema, Karayevia, Nupela, </p><p>Planothidium, Psammothidium</p><p>Chlorophyta: Chlorella, Cosmarium, Oocystis, Pediastrum,</p><p>Scenedesmus</p><p>Cyanophyta: Chroococcus, Gloeocapsa, Merismopedia, </p><p>Myxosarcina, Pleurocapsa</p><p>Mobile Bacillariophyta: Adlafia, Brachysira, Caloneis, Cavinula, </p><p>Craticula, Epithemia, Fallacia, Frustulia, Gyrosigma, </p><p>Hantzschia, Kobayasia, Luticola, Navicula, Naviculadicta, </p><p>Nitzschia, Parlibellus, Pinnularia, Schizonema, Sellaphora, Stauroneis, Suriraya, Surirella</p><p>Diatom growth forms Prostrate/ adnate Achnanthes, Achnanthidium, Amphipleura, Amphora, </p><p>Anomoeoneis, Caloneis, Cocconeis, Epithemia, Frustulia, </p><p>Gyrosigma, Hantzschia, Karayevia, Navicula, Nitzschia, </p><p>Nupela, Pinnularia, Planothidium, Psammothidium, </p><p>Stauroneis, Surirella</p><p>Erect Diatoma, Eunotia, Fragilaria, Synedra</p><p>Stalked Cymbella, Gomphonema</p><p>Filamentous Melosira</p><p>1</p><p>2</p><p>3</p>