'tItnh,ersttl?of \toronto Stubtes :f8lo[oglca[ Series, 'lAo. 37

AN ECOLOGICAL CLASSIFICATION OF CERTAIN ONTARIO STREAMS

By WILLIAM E. RICKER (FR.OM THE DEPARTMENT OF BIOLOGY UNIVE,RSITY OF TORONTO)

PUBLICATIONS OF THE ONTARIO FISHERIES RESEARCH LABORATORY No. 49

TORONTO THE UNIVERSITY OF TORONTO PRESS 1934 CONTENTS

PAGE Introduction . 7 Apparatus and methods . 8 Classification of Ontario streams . 12 Stony spring creeks . 16 Sandy spring creeks . 20 Mud-bottom spring creeks . 21 Humus-bottom spring creeks . 25 Drainage creeks. . . 27 Slow hard-water trout streams; the Mad river I. Physiography . 27 1. Geology . 30 2. Surrounding vegetation . 30 • 3. Climate . 31 4. Physical features of the river . 33 II. Physical and chemical properties of the water 36 1. Temperature . 36 2. Dissolved oxygen . 39 3. Carbon dioxide . 44 4. Dissolved solids . 45 5. Hydrogen-ion concentration . 46 6. Springs . 48 III. A'quatic vegetation. . 49 1. Emergent littoral plants . 49 2. True aquatic plants . 50 IV. Aquatic invertebrates . 51 1. List of species . 51 PAGE TABLES 2. Ecological distribution of invertebrates 57 PAGE 3. Seasonal variation in invertebrate life '. .... 69 1. Physical and chemical features of a spring creek 4. Summary of invertebrate life . 70 (B creek) ...... 17 5. Fish other than trout . 2. Food of speckled trout in B creek...... 20 71 6. The speckled trout-Salvelinus fontinalis. 3. Water characteristics of Dogwood creek...... 23 76 4. Food of fingerling trout in Dogwood creek...... 26 7. Vertebrates other than fish... . '" .. " 87 5. Precipitation at Eugenia, Ontario, in inches...... 32 8. Interrelations of the biota . 90 6. Physical and chemical characteristics of the Mad 9. Summary of Mad river investigation . 91 river at stations 3 and 5...... 35 7. Diurnal variation in water conditions of the Mad Slow soft-water trout streams . 92 river at station 2...... 40 Swift hard-water trout streams . 92 8. Analyses of spring and river waters...... 47 Swift soft-water trout streams ...... 99 Warm rivers . 105 9. Stomach contents of Eucalia inconstans...... 73 General summary . 109 10. Stomach contents of sculpins (cottus bairdii) in the Acknowledgements . 111 Mad river...... 74 Literature cited . 111 11. Food of fingerling trout in the Mad river...... 78 12. Stomach contents of trout of varying size, July 28- August 14, 1930...... 79 FIGURES 13. Stomach contents of trout six to eight inches long.. 80 1. Map of Mad river and vicinity . 28 14. Stomach contents of trout eight to ten inches long. 82 2. Map of Mad river near Singhampton . 29 15. Stomach contents of trout ten to fourteen inches long 84 3. Cross-section of Mad river- . 33 16. Seasonal variation in water of the lower Mad river.. 94 4. Temperature Fahrenheit of Mad river, July 21-28, 17. Food of trout in swift hard-water streams...... 97 1930 , 37 18. Food of Pine river fishes...... 98 5. Daily fluctuation in temperature of air and water at 19. Water characteristics of the lower Oxtongue river ... 100 the Mad river , 38 20. Food of game fish in the Oxtongue river, August 6. Maximum and minimum temperatures of air and 16-24 1929 103 water at the Mad river, June-September, 1930 .... ' 39 21. Food 'of fish i~'~~i'ft 'b;~~~~~~t~~ ~t~~~::~:::'~:.:: 106 7. Fluctuation in temperature and oxygen content of the Mad river, March 21-23, 11931. , 41 8. Fluctuation in" temperature and oxygen content of 42 the Mad river, August 16-17, 1930 . 9. Seasonal variation in temperature, pH, and oxygen 43 content of the Mad river, 1930-1931 . 89 Food pyramid of the speckled trout in the Mad river 10. 105 11. Biotic relationships in swift soft-water trout streams AN ECOLOGICAL CLASSIFICATION OF CERTAIN ONTARIO STREAMS

ABSTRACT The standard methods of limnological investigation, which had previously been used, in Ontario, upon lakes almost exclusively, have been applied, with suitable modifications, t~ a study of str~af!1~ in this province. It appears that the various organic and inorganic peculiarities of flowing waters may be corre- lated to a degree sufficient to allow of a useful, if rather arbitrary, classification being made. The features utilized in this way are of three kinds: (1) physical- character of the watershed; width, depth, and kind of bottom of the stream, temperature and rate of flow of the water; (2) chemical-kinds and quantities of gases and solids dissolved in the water; (3) biotic-kinds and numbers of plants and which are members of the stream community. Such a classification is proposed in this paper, and the peculiarities of the streams of each division discussed in greater or less detail, with especial reference to the food relationships of game fish. Most attention has been given to streams cool enough to contain speckled trout (Salvelinus [ontinalis), and particularly to one slow hard-water trout stream, the Mad river. Economically, these studies should be of value to fish-culturists, as indi- cating what features may most profitably be included-in their necessarily rapid "planting surveys", and as an aid in placing a stream in its proper category when only limited data are available.

INTRODUCTION In the past two decades many biologists have been occupied in a study of the ecological relationships in which the fauna and flora of lakes are involved. To-day, not only is there available a large amount of detailed information on these bodies of water, but various methods of classification have been proposed which are, in their broader features at least, apparently of general application throughout the north temperate region. In comparison with this intensive W~dy of lakes, rivers have been almost uniformly neglected. ith a few exceptions, such ecological data as are at hand c~nsist of notes made incidental to systematic studies, or ~ the ve.ry general observations made ~n c~mn.ec~ion.wit.h sh-plantmg surveys. The reason for this discrimination IS Probably to be found in the overwhelming variety of habitats 7 8 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 9

presented in streams and rivers, the inadequate syste . Volume of flow was calculated from the rate plus the treatment of their fauna, and the lesser economic impo ~abc sured width and average depth of the section; no correc- a of their fish. ranee Ill.e was mad ef or"b 0 tt om d rag. " n Important information upon the general ecolog tlO Temperature was taken by means of a Tycos armoured certain streams in which speckled trout live is to be f y of ntigrade thermometer, marked off in degrees and accurate und in publications by Hankinson (1922) and Kendall and Do ~ one-fifth of a degree. Unless otherwise stated, readings (1927) .. A study 0hfthbe physical and bi~tic peculiaritie~n~~ cere taken three inches below the surface. On the Mad mountain streams as een made by Steinmann (1907) d river a Negretti and Zambra continuous recording ther- Thienemann (1912) in Europe, and by Dodds and Hi an 1Il0rneter was also used. Its graph (figure 4) gives the tem- (1924a, 1924b, 1925) and Muttkowski (1929) in America.sa~ perature in degrees Fahrenheit. It was checked by a Negretti number of authors have concerned themselves with th and Zambra standardized Fahrenheit thermometer. Owing physical and chemical characteristics of the waters of Ameri~ o pointer drag, the recording thermometer registered 0.50 F. can streams: Belding (1928), Butcher et al. (1927), Coker too low when the temperature was near a maximum, the (1925), Cowles and Schwitalla (1923), Creaser (1930), Faigen- e amount too high when approaching a minimum, and baum (1930), Gutsell (1929), Powers (1928, 1929), Shelford arious lesser amounts elsewhere. It was impossible to (1.925), and.Wagner (1926, 1927, 1928). Publications dealing rrect for these variations. Correction has been made for with the Invertebrate fauna are numerous but widely constant error: +1.20 F. in 1930, and +3.80 F. in 1931. scattered, are usually purely systematic, and generally deal Air temperature was recorded by means of a maximum with only one species or group of species.The papers d minimum thermometer, accurate to one-half of a degree of Clemens (1917), Leathers (1921), Muttkowski and ahrenheit; it was mounted near the river, in the shade of Smith (1929), Needham and Christenson (1927), and some thicket, five feet above the ground. others have given an account of the place of certain aquatic Oxygen content of the water was determined by a in the life of a river. odification of Miller's method, using ferrous-ammonium In 1930-1, the author endeavoured to obtain information phate for titration. The solutions were standardized by on all of the above points from a single stream habitat-a ference to Roscoe and Lunt's table of saturation values short section of the Mad river-so that an attempt could be .utton, 1924, in appendix). Distilled water was saturated made at discussing the relationships of flora and fauna to th atmospheric oxygen at 180 C, in the fashion described each other, and to the physical and chemical peculiarities ~f Y Sutton. This standard solution was considered to be the water. During the course of this investigation the pOSSI- ~ p.er cent. saturated, its oxygen content, determined by bility suggested itself of extending to streams generally t~e trahon, was compared with the figure given by Roscoe and systematic ecological treatment which lakes have alrea Y ~nt (allowance being made for atmospheric pressure, as received. Io~), and a corrective factor found for each sulphate ution In some of the earlier work this standardization ApPARATUS AND METHODS ashnot done in the laboratory, so samples of water taken I. Water f t e field, at the foot of a long series of rapids and falls, Rate of flow was determined by finding the Ier:gt n~e eICreonS iIdered to be 100 per cent. saturated, and the factor time in which a floating stick was carried a measured dlS a CUlated from them. by the current. All tables of saturation values are for an atmospheric 10 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 11 pressure of 760 mm. (29.92 inches) of mercury. These lllust sing the usual amount of indicator. When only half be corrected to give the value at the pressure prevailing 6t h¥s amount was used, the intensity of the colour was, of when the determination was made. Pressure varies with o t e reduced, but its hue also changed, and indicated a pH the altitude of the station where work is done, and also c~~~o~t 6.6. However, pH readings from soft waters, even if varies daily according to weather conditions. In lieu of a ~ot accurate ab~olutely, are comparab.le ~mong themselve~. barometer the author has used the following formula to DeterminatlOns of free carbon dioxide (C02) and bi- obtain actual pressure; it is derived from one given by Geddes rbonate (HC03) were made by titrating with N /50 sodium (1921, p. 110): H c:rbonate and /50 sulphuric acid, using phenol phthalein log p=log po-0.00001570 ~nd methyl orange respectively, as outlined in Rept. Onto where p = pressure at elevation H feet, and Po= pressure Board of Health (1919). Hardness was tested by means of referred to sea-level, obtained from the daily weather bulletins a standard soap solution. The author is indebted to Mr. issued by the Dominion Meteorological Service. E. S. Pentland for many determinations of the chemical The elevation of most stations may be found in White composition of the water. (1925). The above formula is accurate at 15° C. air tempera- ture. A deviation of 10° C. produces an error of only 0.2 II. Invertebrates per cent. at 1,500 feet altitude. For more accurate work, Samples of the upper seven em. of a river bed were taken or at hizh altitudes, the following formula may be used: by means of a dip net 14! inches (36.7 cm.) in diameter. The H bag, through which the water and mud were strained, was of log p=log Po-0.00453 T marquisette, having 24 threads to an inch (9.4 per cm.). where p, Po, and H are as above, and T = absolute temperature After taking a dredging, the area of the hole left on the of the air at elevation H feet. In the present work, correc- bottom was measured, with a possible error of about ten per tions for atmospheric pressure have amounted to from two cent. For a few of the deeper water collections, an Eckman per cent. to six per cent. d d dredge having a gape of 77.5 square inches (500 square cm.) Reference to Whipple and Whipple's table (St,w ar was used; the constant clogging of the jaws and the incon- methods of water analysis, 1925, p. 62) shows ~hat the l~s:~~ venience of operating it from a canoe limited its usefulness. ing of solubility of oxygen because of salts dissolvedJ 1 After a dredging was washed in the net, the living animals water may be neglected in fresh waters w~ich contalll ess Werecarefully picked out of the weeds, sand, or debris which than 250 parts per million of solids in SolutlOn. . g ~mained, and preserved in 70 to 80 per cent. alcohol. The . h b ured ustn Hydrogen-ion concentration as. een meas 01 blue, arger and rarer invertebrates, such as Benacus or Helisoma, a La Motte colorimetric comparator, with bromthym ters 'Nere often taken individually as they were seen. Imagos of phenol red, .and thym?l blue indicators. In hard b:~atis~ aquatic insects were collected by means of a net, or from which contain much bicarbonate, these appear to H f the Under leaves of trees. factory; but in soft water it would seem that the p Of the r In this paper four words denoting frequency of occur- indicator used (which is one-tenth of the volum~ :he re- ~nce have been applied to the invertebrates of the stream water used) has a significant effect upon the pH, 0 had a ttolll with the following arbitrary values: suIting mixture. For example, the Oxtongue nv.~f. n e"- ~~han 15 per square foot (=0.0929 square metre): Abundant bicarbonate content of less than ten parts per mld~og' was to 5 per square foot (= 0.0929 square metre): Frequent e,..er ther square foot (= 0.0929 square metre): Occasional pressed as CaC03. On July 18, 1930, the pH rea 10 an 2 per square foot (=0.0929 square metre): Rare EcOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 13 12 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS

III. Fish uently difficult to evaluate. The following is a list c:on~ more important: Sculpins, sticklebacks, and trout less than one and of t ~. Chemical compositio~ of the .basic rocks a?d of the h~lf inches. long were often taken in a dip net. A ten-foo~ of the region through which the nver flows, deter- rmnnow seme was used to capture slightly larger trout and soU which . the bicarbonate content and hardness of the water many other fish. Large trout, creek chub, shiners ,.,etc We re ~e~ith carbon dioxide content, its hydrogen-ion concen- most often taken by angling, with either worm or as bait. an tion. The waters of Ontario rivers are rather sharply The length of ~ fish :vas measured in inches from tip of :: 'ded into "soft or brown waters" and "hard or clear snout to fork of tall. GIrth .was measured immediately in :V:ers" corresponding roughly to the division of the pro- front of the dorsal fin. Weight of fish heavier than one • ce into a region of igneous rocks (including most of the ounce (2.8.4 grammes) was measured by means of a postal pre_Cambrian shield) and regions of sedimentary rocks s~ale which was accurate to the nearest tenth of an ounce. LIghter fish :vere weighed on a balance accurate to 0.Q1 (mostly of Ordovician, Silurian, or Devonian age). grammes. WIth a few exceptions, fish more than six inches B. Type of soil and vegetation of the watershed, which (15.2 cm.) long were measured and weighed soon after they the principal factors in determining the turbidity of were caught and while they were still fresh; fish less than water. that length were measured about seven months later after C. Speed of current, which may be divided into (1) slow being preserved in formalin and alcohol. ' ess than 1.5 feet (0.46 metre) per second, and (2) fast- re than 1.5 feet per second. IV. Stomach analysis D. Type of bottom: Vegetable debris, mud, sand, gravel, The contents of the fish stomachs were analysed singly. es, boulders, bedrock, or hard pan. The total volume of the contents of each stomach was E. Temperature of the water. found by displacement of alcohol or water in a graduate. F. Width and depth, which with C determine volume Iterns were then sorted and counted and the percentage of low. the whole which each group formed was estimated. From G. Flora, which is determined by A, C, D, E, and this the actual volume of each kind of food in each stomach bly F and H. was obtained. Averages for a series of specimens were ob- H. Fauna, which is determined by C, D, E, F, G, by tained by adding together these volumes then calculating . ' phical position, and by the presence of barriers to Its percentage of the total volume of all the stomachs. bon. When only a few large items occurred in a stomach, I. Oxygen and carbon dioxide content of the water, their several volumes were often found separately, by dis- are influenced by almost all of the above factors. placement. In the case of very small fish, the total volume, as well as the percentages, was estimated. Carpenter (1928) has proposed a classification of the fas of ,?reat Britain, on the basis of some of these . It IS, however, incomplete in some respects when CLASSIFICATION OF ONTARIO STREAMS n to Ontario waters, and includes some types which The factors to be considered in making a classificatiO~ ~e:act equivalent here. Shelford and Eddy (1929) am and Lloyd (1930) have given some considera- of streams are to a great extent interdependent, and a 14 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICALCLASSIFICATION OF ONTARIO STREAMS 15 tion to differences between various American stream Brasenia or Castalia; volume of flow on June chiefly as regards their fauna, but they too omit mans, 1 not greater than 100 cubic feet (2.8 cubic Ontario types. It has seemed better, therefore, to make Y metres) per second. preliminary grouping of Ontario streams into natural, thoug~ (ii)Slow soft waters. Bicarbonate content less intergrading, classes, without direct reference to previous than 25 parts per million (expressed as work: CaC03), hardness less than 50 parts per million; vegetation including Brasenia or A. Creeks. Volume of flow less than ten cubic feet (0.28 cubic metre) per second on June 1; width less than ten Castalia, never Chara; volume on June 1 up feet (3.0 metres). to 500 cubic feet (14 cubic metres) per second. 1. Spring creeks. Permanent, usually spring fed; maxi- mum summer temperature lower than 20° C. b. Swift trout streams. Stony bottom; moderate to rapid current; vegetation of Cladophora or aquatic a. Stony bottom, moderate to rapid current, vegeta- mosses; typical invertebrates Hydropsychidae, tion of aquatic mosses. Heptagenidae, Simuliidae. b. Sandy bottom, moderate to rapid current, bare of (i) Swift hard waters. Bicarbonate content vegetation. greater than 100 parts per million (expressed c. Mud bottom, slow current, vegetation usually as CaC03), hardness more than 150 parts per water-cress, or none. million; Simulium larvae merely freq uen t ; d. Bottom of dead leaves and other vegetable debris, volume of flow on June 1 not greater than 150 slow current, vegetation of mosses or none. cubic feet (4.2 cubic metres) per second. 2. Drainage creeks. Not spring fed, or far from springs, (ii) Swift soft water. Bicarbonate content less often completely dry in summer; maximum summer than 25 parts per million, hardness less than temperature above 20° c., usually much higher. 50 parts per million; Simulium larvae ex- tremely abundant; volume of flow on June 1 B. Rivers. Volume greater than ten cubic feet (0.28 cubic up to 500 cubic feet (14 cubic metres) per metre) per second on June 1; width greater than ten feet second. (3.0 metres). 2. Warm rivers. Maximum summer temperature in ex- 1. Trout streams. Maximum summer temperature not cess of 24°C.; volume of flow with no upper limit; .. I .. fi h Salve- in excess of 24° C .; pnncipa piscrvorous sn, principal piscivorous fish of the families Centrarchidae linus fontinalis. and Esocidae. a. Slow trout streams. Mud over most of botto~i a. Stony bottom, moderate to swift current, sup- slow current; vegetation of Nymphaea, sever porting typically a Cladophora-Hydropsychidae- species of Potamogeton, etc. t Etheostominae association (Shelford and Eddy, . b conten (i) Slow hard waters. Bicar onate sed 1929). es greater than 100 parts per million (expr per b. Mud bottom, slow current; with a very varied as CaC03), hardness more than 150 part: not biota, including Nymphaea, Unionidae, Catos- million; vegetation including Chara, hu tomidae, and many Cyprinidae. ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 17 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 16 ..; .c, . The distinctions between swift-stony and slow-mudd u~ •••• UJ ~8~....• types are, perhaps, the most fundamental, from the point ~ c.,, view of the biota, of any which were used in preparing t~ .c, eo ~ o"'~ table. They have been relegated to the third rank for the :>. 0. 0>"'0 X ....•....• sake of convenience, because swift and sluggish reaches oft e 0 ci. alternate along the course of a single stream. en ....; C'->",'HQ The "warm rivers" are entitled to much greater sub- <, (jj~(jj o division than that shown, but almost no information i u available which treats of Ontario examples. s ~ :r: The author has visited every kind of stream mentioned 0. I~~~~~oo but the amount of attention which each has received has by aU0.' no means been uniform-varying from a single casual exami- .,0 I~":~~Oll;) r< ....•....• nation to a prolonged period of careful study. The Mad '" river has been most favoured, and the description of its '0 "- ~---:- UJ o ~'-~ ,* ., . 0 . U) various aspects will constitute the bulk of this paper. Never- •... oq::::: ='"'" ,"'~ ::l :> ~u.,o. theless, each type will be discussed in its turn, following the ] .,~1iJ~ ,* order given in the above outline. -;; .j...Joo... .C'->C'-> o ~~~~ .....•....• '8 o~ ...c, STONY SPRING CREEKS o ., "0 ~~~ • "" <0 C •..•0." ·00 "B" creek, one of the tributaries of Little Wonder pond, '" <~Q)~"O~ at Horning's Mills, Ontario, is in its upper reaches a typical "§ .~ bO..c~ stony spring stream. It rises from several springs in a small ..c '" p... f.'::o t :""0....• cedar copse, flows out into a small pool in an old farmyard, <~~~'-., then through an open stony channel 200 feet (60 metres) long, .... .w.. which is the typical "upper section" of this description. ~ ., e a e 8 ci.ci.ci. Leaving the farmyard it enters a wood, mostly of evergreens, ;; 000 ~ C'->C'->C'-> flows for about 300 yards (270 metres), and is joined by·t cr.icr.icr.i larger creek which had its origin in springs about a. torrn ae (1.6 krn.) above. The combined streams flow out In re ."00•.. '" I"""""" 0."'0>...:>.:>•.:>. grassy glade beset with scattered elms and popla.rs. 1 II lBeoW er I.-"...a-',....a',-a.'...', ''' the current again quickens and enters the typlCa re section", distinguished from the upper by a higher and ru;he : c c · 00 variable temperature and a greater volume of flow. was ., :'.r::'~ two sections are compared in table 1. On July 24 there The (.) · ~ a:l '" UJ UJ UJ a temperature difference between the two of 5.40 5° ~ bO •..•••• C. C. .-C. 0,..>,.: ao.b highest temperature recorded during the season was I8'bablt U);:J...:I at 3.00 p.m. on July 9-a very hot day; it seemS pro 2 18 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 19 that the absolute maximum would not exceed 20° C. The Leuctra. U and L, occasional. pH was less in the upper section than in the lower, and the Nemoura sp. (with gills at neck). U, frequent; L, oxygen content greater, though the water of both reaches occasional. had reached saturation in this respect. Both were rich in Nemoura sp. (gill-less). U, frequent. lime and carbonates, to an extent of 150 to .200 parts per Trichoptera million. The volume of flow of the upper section was nearly Rhyacophila fuscula. L, occasional. constant throughout the summer; that of the lower increased Mystrophora americana. L, frequent. to double its normal value after a heavy rain. On such Hydropsychidae. U, occasional; L, frequent. occasions the water became rather turbid. Both sections Philopotamus. L, abundant, in moss. had a moderately rapid current, and a bottom of gravel Or Stenophylax scabripennis. L, rare, in slower pools. small stones. Neophylax, d. automnus. L, occasional. Aquatic vegetation in the stony sections of B creek Hesperophylax designatus. U, abundant; L, occasional. consisted only of lithophilous and clinging algae, and mosses Larvae, prepupae, pupae and imagos were taken such as Fissidens, Fontinalis, and Hygrohypnum. on June 7. On September 7 young larvae were Several collections of aquatic invertebrates were made common. in the stream. Characteristic organisms were the stonefly Diptera Nemoura and the caddis Hesperophylax designatus. Both of Chironominae. U and L, frequent. these are more abundant in the cold upper section than in Tanypinae. U and L, occasional. the warmer stretch below, and are absent or rare in larger Simulium. L, frequent. streams. In the following rather incomplete list, the letter Coleoptera U indicates that the organism in question was found in the Helmis. L, occasional. upper section; L, in the lower section of the creek. Gastropoda Gyraulus, d. parous. U, rare. Turbellaria Pbysella. U, rare; L, occasional. Planaria. L, occasional. Three species of fish were found in B creek: Oligochaeta Cottus cognatus. Rare. One specimen was taken 50 Lumbriculidae. U, rare. feet from the head of the creek. Hirudinea Eucalia inconstans. Rare in side pools of the lower Glossiphonia complanata. U, occasional. section. Nephelopsis obscura. U, rare. Salvelinus fontinalis. Fingerling speckled trout were Ephemeroptera abu?dant in bo.th the upper and lower gravel Leptophlebia. L, frequent. sections, and fairly common in the slower inter- Ephemerella spp.L, frequent. mediate reaches. Adults were not seen in the Baetis spp. L, abundant. shallow exposed rapids, but were common in a Iron pleuralis. U, frequent; L, occasional. A few deep sheltered pools. Plecoptera • few small trout were obtained for study and the YSISof th '. , Chloroperla. U, frequent. e th eI~ stomachs IS presented in table 2. In early Alloperla? L, occasional. e fingerlmgs were not yet large enough to utilize any 20 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 21 part of the rich invertebrate fauna except the Chironol1J.id larvae and pupae, and a few other small insects. By August tream, rising from springs in a wooded valley and flowing Sut into a swampy meadow. Its average width is three feet 1 their percentage consumption of midges had been redUced (1 metre), and volume of flow 1.1 cubic feet (0.031 cubic by one-half, and the gap was filled by I?ayflies, caddis, beetles, metre) per second in May. A water analysis, made at and terrestrial insects. Three yearhng trout taken at the 10.00 a.m. on May 27, 1930, was as follows: temperature same time consumed a mixture of insects, chiefly caddis 0 larvae. 7.0 c., pH less t?a.n 6.8, oxygen content 7.8 cc. per litre, TABLE2. Food of speckled trout in B creek 11.2 parts per million and 100 per cent. saturated, acid 3 carbonate (HC0 ) 12 p.p.m. expressed as CaC03, free carbon - dioxide 1.3 p.p.m. In summer, the volume decreases to Inter- Upper Lower Upper mediate 0.8 cubic feet (0.023 cubic metres) per second, and the section section section section temperature rises to about 200 C. on hot days. Date taken ...... June 7 June 7 August 1-2 August 1-2 In the sandy beds which constitute most of the bottom Number of stomachs examined. 4 1 9 3 of the stream, the author was unable to detect any life Average length in inches ...... 1.36 1.84 2.28 4.83 Variation in length ...... : . 1.25-1.50 - 2.06-2.69 3.62-5.44 whatever. The trout in these places must eat either terrestrial Average volume of contents in organisms, or the insects which cling to logs, etc., in the cubic mm ...... 16 19 71 290 Average number of Nematoda .. 0 0 + 3 water, or insects washed down from a stony bottom. The fish observed in this stream were the speckled Vegetable matter ...... -- + 5 Aquatic Insecta trout, and, in the lower reaches, the creek chub (Semotilus Ephemeroptera: Baetidae .... - - 19 5 Mromaculatus). None of the trout seen was over seven inches Plecoptera ...... - 37 5 2 Trichoptera: Larvae '!,nd (18 cm.) long, although longer specimens are said to have been pupae ...... - - 11 35 captured. Cases ...... - - - 9 Heteroptera.: Corixidae ...... - - + 2 Small cold creeks with sandy bottom are not as common Diptera: ...... 94 16 47 8 southern as in northern Ontario, but, when they occur, Simuliidae ...... - - 2 8 Others ...... 6 37 2 1 ey seem to be equally deficient in living organisms. Evi- Coleoptera ...... - - 8 8 entlY.the carbonate content of the water is not an important Terrestrial Insecta **...... - 10 6 14 0 10 18 19 ctor III determining the dearth of life. It is interesting to Total surface food ...... 81 Total bottom food ...... 100 90 82 te that the same condition is prevalent in lakes. For ple, Rawson (1930) has shown that in lake Simcoe sandy Sand *Includes Polycentropidae, Hydropsychid. ae, H espero phY lax des~gnat u , :Jhes are much less productive than tho~e with stony, other Limnephilidae. . C It. dy, Or weed-covered bottom. **Includes Thysanura, Homoptera, Diptera, 0 e0t: er\ents a figure l~- Note' In this and all subsequent tables of stom~c ccinup o'fthe item l~ dicates what per cent. of the total volume of cont~ntdsliS m~h~n one-half of on .(+) shows that the Item compnse e~s MUD-BOTTOM SPRING CREEKS ~~:~t~~~:of ~~~s:otal, a dash (-) that it was entirely lacking. ~ogWOOd creek, a tributary of the Mad river in Grey SANDY SPRING CREEKS r n Y, Ontario, rises from springs, and for most of its nea . . p' ula lak e, r flows w.ith gentle current through an evergreen Tally-Ho creek, flowing mt? emns. soft-Wate P. When It emerges from the tall timber its channel Huntsville, Ontario, is typical of this class. It ISa hun . h " g WIt Myrica Gale, meanders through a swale of ECOLOGICAL CLASSIFICATION OF 0 TARIO STREAMS 23 22 ECOLOGICAL CLASSIFICATIO OF ONTARIO STREAMS small willows sp.) and until it rn CO.-0>0>0>0>0>00 the larger trout stream (figure 2). At this point its aYeeets width is about five feet (1.5 metres), and depth two feet r~g~ c:: metre). In early summer its volume of flow was 4.6 cub: .,E OOt--COCQO~t--CQ ~ 0. r-:oo00 66c<....i•0..00..• feet (0.13 cubic metre) per second; in August this w IC o ci. reduced to 2.0 cubic feet (0.057 cubic metre) per. secon~ ....• lQ•••.OlQCQt-• -lQOO which low level it maintained up to the end of the followi <, u .Qco ;::l COlOCOlQlQCQCQlO 0 o ~ The highest figure recorded in Dogwood creek was 16.0 c., c ~-j---:------I 0 at 4.00 p.m. on a hot afternoon in July; the lowest was 2.2 C. 0. S lOt--OOO>Nt--O at 10.15 a.m. on October 20. The oxygen content of the ~ cJ

Oligochaeta The fish found were: Salvelinus jontinalis, Cottus bairdii, Tubificidae. Frequent. Eucalia inconstans, and a small minnow. Only trout were Hirudinea common. The specimens seen were chiefly fingerlings, which Glossiphonia complanata. Occasional. early in the year frequented the very shallow borders, often Haemopis plumbeus. Rare. resting on the bottom. A few yearlings and two-year-olds Nephelopsis obscura. Rare. were captured, but they were not very common. In the fall Crustacea the stream is frequented by adult trout, journeying to the Hyalella knickerbockerii. Abundant. springs above. E phemeroptera The food of some of the fingerlings is listed in table 4. Hexagenia. Rare. A small creek of this sort produces large quantities of the Ephemerella temporalis. Rare. preferred food of the smallest trout-Entomostraca and Leptophlebia. Occasional. Chironomid larvae-but its supply of medium-sized aquatic Plecoptera insects (such as Baetis) is less generous. Hence in mid- Leuctra. Rare. summer, many of the fingerlings desert the creek for the Nemoura. Rare. river below where mayfly nymphs, etc., are commoner. Trichoptera Those which remain feed to a great extent at the surface of Limnephilus. Rare. the water, taking a variety of terrestrial insects. Many of Halesus guttijer. Rare. the common invertebrates of the stream, e.g., Oligochaetes, Unknown Limnephilid. Occasional. leeches, most caddis larvae, Pisidium, Physella, and Valvata, Diptera are unavailable to small trout, by reason either of their large Simulium. Rare. size or of their secretive habits. Chironomidae (det. Johannsen) Procladius (group adumbratus). Occasional. HUMUS- BOTTOM SPRING CREEKS Pentaneuria (Ablabesymia) (group flavijrons). Occasional. When a spring creek flows with a gentle current through Cryptochironomus. Occasional. a deciduous forest, dead leaves accumulate on the bottom, Others. Occasional. anbed with other decaying vegetable materials, form a rich Culicoides. Occasional. d of humus. The invertebrate population of such creeks Chrysops. Rare. often very great in numbers, though not especially varied. Coleoptera theedham and Lloyd (1930, p. 36) describe such streams as Hydroporus depressus. Rare. titey are found near Ithaca, N.Y.: their fauna consists, in Pelecypoda (det. Sterki) Be .typical leaf beds, of Tipula abdominalis, Nemoura, Pisidium overi. Frequent. .~hs, Leptophlebia, and Gammarus, and on the more open Pisidium variabile. Occasional. Co ~ bottom of the large caddis Halesus guttijer, Sphaerium, Pisidium d. sargenti. Occasional. .; ule~aster, Boyeria, Gerridae, burrowing mayflies, and Pisidium d. milium. Occasional. c~nslderable variety of the lesser midges". Gastropoda III Sahara" creek, one mile north of Oliphant beach, Physella integra. Frequent (det. Clench) ce COunty, Ontario, is of this type. The country in which Valvata sp. d. sincera. Abundant. II 26 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 27 it rises consists of sand dunes mostly covered by a tho Physella were occasional, Limnephilus, a Hydrophilid beetle, growth of beech and sugar maple. When examined on J l~k and a big Tipula rare. No fish were seen in the stream. 12, 1930, its volume of flow was 1.5 cubic feet (0.042 cu~t metre) per second, and temperature 11.3°C. at 9.10 a C Its average width was four feet (1.2 metres), and depth e."l11 · DRAINAGE CREEKS - Ig t h Because of their high temperature and irregular water TABLE 4.Food of fingerling trout in Dogwood creek supply, drainage creeks are not suitable for most fish, and have not been studied. May 22,1930 July 25,1930 SLOW HARD-WATER TROUT STREAMS:THE MAD RIVER Number of specimens examined . 10 3 Average length in inches , . 1.14 2.29 Variation in length . l. 00-1. 30 2.00-2.50 Streams of this type appear to be rare in Ontario, Average volume of contents in cubic mm . 4.8 35. Average number of Nematoda . o because in most regions of calcareous sedimentary rocks, the + land has been cleared of vegetation to such an extent that Vegetable matter . 3 Entomostraca I any large slow stream is hot enough to be classed among Cyclops . 5 the" warm rivers". The one example studied by the author Canthacamptus . . .. . 18 Ostracoda . 4 -the Mad river-is a rather famous trout stream. H yalella knickerbockerii _ . 4 Aquatic Insecta I. Physiography Nymphs of Plecoptera . 5 Larvae of Trichoptera . 8 Simuliidae . 3 The Mad river is situated in Gray and Simcoe counties, Larvae and pupae of Culicidae . 11 Ontario, in longitude 80° 15' W. and latitude 44° 20' N. Its Larvae and pupae of Chironominae . 35 15 Larvae of Tanypinae and Culicoides . 12 total length from the source to its confluence with the Netta- Adult Coleoptera (Hydroporus) . 31 wasaga river is about 40 miles (64 km.). Rising in an ever- Terrestrial Insecta green swamp a mile north-east of Badjeros, it flows north Homoptera . 4 and east seven miles (11 km.) to Singhampton; turning Lepidoptera _ . 2 Diptera . + 23 south-east it runs for seven miles, and is joined by the Noisy Coleoptera . 4 river, an important tributary of nearly equal volume. The Hymenoptera _ . 5 Total surface food _ I 3 38 COl11binedstreams continue south and east, passing through Total submersed food , 97 62 ~reel110re, then turning northward to join the Nottawasaga nver 20 miles (32 km.) from the point where the latter stream el11pties into Georgian bay. inches (20 cm.). The bottom was of sand covered bYtea . The section here studied is in the upper reaches of the light layer of silt with many leaves, sticks, bits of bark; e na hver, six miles (10 km.) from its source. It is one and one- and with logs frequently blocking the channel. T~e n:~ttS' al{ miles (2.4 km.) long, extending from a point on the was found to include an abundance of Ga:nmaru~ !~ml rva.e ~avel road a mile south and west of Singhampton, down to Pisidium idahoense (det. Sterki), and Ltmnephthd a and ~ glen half a mile east of that town. At its lower end is a (not Halesus guttifer, however). Chironomid larvae lllill dam, which has flooded the banks for some distance 1) 1) I ·so ••.OOS. I 1) 'l1. ':>9S;: 't:t'Dd '.I." 'n, NI 'Q '0 1) .MO'"1;:1 .0 '!IIIrtM"1OA 'IIAlfI) a.~nE>l.:d 'D '0 Ld~'11-t9NIS~ ~3AI~ 1) 'D 1) 1) '0 o tl OOOMO~I-l '0 " -0 1) '0 'l) ••• to \)

y 'l) 'D ..J__ o_- "0 ---- . ••• --- 'iI .•. , .•. SN3a~~~"i"3 , '* .,

•••

1) .., '0 ., \)" , ., t> of' SOOOM a3)(11~ "0 '0

(f) -::s0: ~ ~ <-< (f) ~ .>•..- 0..... °2 ~ °u -0: l or; <-< >- .~j "0 Z c:: 0 ••• '\ oS ~ .,•.. 0 Z > o-=: z 0 "0 0 oS ..... ~ ~5 ::E -<0-<: (0. w u USI '0 ..... > 0. ~..... Ci. oS (fJ Z ::E -(f0J: ...:l 4: ,..; U

00 C'I 30 ECOLOGICAL CLASSIFICATION OF 0 TARIO STREAMS ECOLOGICALCLASSIFICATION OF ONTARIO STREAMS 31 back. The mill has been in operation for at least 75 Year dduouS hardw?ods on most of the high ground, mixed with The extent of the river and of the section studied is illu:~ ck ash, white elm, cedar, or even tamarack in . bla ., mOIster trated in figures 1 and 2. . . locations, ~s at t he nver s edge. Pine seems to have been Several small tributaries flow into the. nver along the rare, even III early days; a few stands of balsam and white course of the mile and a half under observation. The largest spruce occur on sandy knolls. of these, entering near the upper end, has been called Dog_ The Mad river has suffered less from deforestation of wood creek. its headwaters than have many Ontario streams M 1. Geology hundred acres of land just south of the area under stud any covered by damp forests of cedar, balsam spruce y .nd The basic rock of this region is the hard Lockport tamarack; the effect ?f this large area of bush is to retain ~~e dolomite a sediment of Middle Silurian age. It is almost water, les.sen the spnng .floods, and give permanence to the completely covered by glacial drift, .consisting of sandy clay, many spnngs of the region. Certainly, however, enough of with many large stones, mostly of hm~, thoug~ a few are of the land has been cleared to make the river's volum f f . h . eo ow izneous origin, brought from afar dunng the Ice age. The higher III t e spnng and lower in the summer than wa edge of the Niagara Cuesta is close to Sir:ghampton, and over formerly the case. s it the river must fall to reach the plain below-a drop of 3. Climate about 600 feet (180 metres). In doing this it has cut a st~ep narrow valley three miles (5 km.) long, the bottom of which Singhamp~on is situated in the highlands of south- is at one point 300 feet (90 metres) below the le:el of the estern Ont~no, at an altitude of about 1,500 feet (460 table-land immediately above. Along the north SIde of the ~ etres). ThIS has a rather important effect on the climate. glen the uppermost massive layers of dolomite form a per- emperat~re. Not extreme. The maximum summer tem~ pendicular cliff 50 feet (15 metres) high. I~ the va'lley, t?s~ ..Perature III 1930 was 860 F. (300 C.), while the nights were river runs swiftly over a stony bottom; this sectlO~ IS d d ays. co~l. The earth freezes and is covered with snow tinguished as the "lower Mad river", and will be ~hs~uss~f ettme III December; it does not thaw until the latter part March W· .. I. below. Above the mill dam, which marks the be~lllll1n~ -250• inter mmrmum temperatures would probably 0 the fall, the current is slow; this is the section descnbed ere to -40 F. (-320 to -400 C.). and is referred to simply as "Mad river". indo Proxim·t t I k H tice bl 1 y 0 a e uron may account for a very 2. Surrounding Vegetation ci:U e .tendenc~ toward strong steady westerly winds, y In the winter and early spring. . long the Figure 2 shows the distribution of vegetatlOn a tends infall. The a ... course of the stream. On the north-west a forest e\ the 'on if· verage precrpitanon in the Mad river unbroken for several miles.To the south a~dfi ~~scrops. es (~.6a~~ constant throug.hout t~e year, at about three country is well cleared, and used for pasture an e h most Decemb .) per month. It ISleast In August and greatest is for t e . However the actual course 0 ft he st ream ) d 1S a the er.In every month of 1930, considerably less , . h (upper en part lined by trees. ear ItS sout ern . site of an light dUs~al amount of moisture fell culminating in a "beaver meadow"; a swale of Carex rnar king the rnon de- 'Pitati~~lng Augus~ and September. ' Table 5, showing old beaver pond. The forest consists of the corn at Eugellla, a town 13 miles (21 km.) west of ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 33 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 32 Singhampton and at nearly the same elevation, has been C'I 10 ~ upplied through the courtesy of Dr. J. Patterson, director o C'I ••..• o \ ~ ~ :6 ..... ~f the Canadian Meteorological Service. •...0• 0 :>o \ 0..' lQ ~ 00> •...• 4. Physical Fea.tures of the River ~... C"1 ~ ee c Contour and bottom. An ideal cross-section of the Mad cQ 0 •...• 'C•il... 'd \ ~ ~ cQ o ••..•0> •...• 0. . . o o J\ C'I 0 C'I •.... '-e--p-eET---- 1-6 I A s•.. 0> 0 cQ 0>•.... ~0. \ 0..' ~ cQ o ~ •...• 'a < C'I cQ C'I - FIGURE 3. Cross-section of Mad river cQ. lQ. ~ . .., "@ \ ~ I- I- o cQ •...• .c lQ '" ....c<•0 i •...• •.. (l:l ~ ..... shallow flat (A). The bottom of region A is of mud, and ..l .£ ell 8Upports a flora of mud-loving plants. Its depth is 0 to <: E-< ..c\~cQ~ I-lQO> v ~ oc-r.fl C; E-< station 8. (The location of the various stations is shown ~~ E-< figure 2.) Variations are of three sorts: first, an increase '" •... v~•.0• the width and depth of the channel, chiefly at bends, ~•.... ~ 3 34 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 35 which form pools up to nine feet (2.7 metres) in depth ..... at station 2; second, an increase in the extent of the shah as 5 e c: ee ~co...... ••.•N •.•• u B·g 108 ••.•00 ••.••.••8 ••.••0000 ~ '""cd.j..l 1'"""'1~1'"""'1 1'"""'1 ~ Ol :Sgg;sR~ region, best represented by the broad flooded borders of the ~(/l ...• river near the mill dam; third, a decrease in depth of the c: E channel and absence of mud flats, with which is correlated e "bIl .CX:~~ 0 00~ •.••0 :>, Ii IrOOO--:~ •c.••xO•:~~r.••N --.0l:~ ••.•0l X ,...... •••••• 1'"""'1 1'"""'1 6 :6C"i"";6ac:i increase in current speed and a bottom of larger stones--i an Ii ...• 1'"""'11'"""'11'"""'11""""1 e 0 an approach to the rapid water conditions seen in the low· . -I It:> ...i "0 Mad river. Station 5 is of this type. er <, .c:~~ 0 O~Ott:>co Cl u I~~~~~~•.•••.•••t.••t:>c•.••xtt::>oo ·coooco ~ u •... :~ac:iac:i~.o

'"•.••'" 00 O•.••co •.••~ B 0.. :~~ :~~~ ~ :ac:i~~~~ greatest volume was determined at the time of the spring .<•f.). ~ flood in 1931; in other years the volume of flow has risen 1;) tt:> tt:> •.••tt:>tt:>lQ tt:> far above this figure. On the other hand, the lower figures .;::> ::s ~ ...... tt:> tt:>tt:>tt:>lQtt:> .;•••r. 0 tt:>00<0:)0 •.••000l 00<0:)<0:)N ...... ~OOr-l~<:.OC'I:)~,..... are probably near the absolute minimum, on account of the al .oj.. lQlQco •.••cott:>t:>tt:>•.••COCOOOO •.••NOOOO~NOOO the time it was studied. The more typical sections, such o .•.....••....•cq,..... ,..... as station 3, had speeds somewhat less than this figure, ~ .~ " il: o 1;)::0- averaging perhaps 0.2 feet (0.06 metre) per second in July 8 o:.a 0.. c: .~ E«=:::s •..•o tt:> 'lQN~~"""'-~ ••.•-_tt:> 8'" 8:>' 0> r-..: •..•-N-.!:J ••• >.NO .. . of the ~ C\l(j)~C\l ~ ~ ;.~ rl •..••..•N8 " •..·..c:N :>''' :>,:>,~~ 0 ~::s::::;:: "..0"'<..>_ Water supply. Most of the water In this sectlOn this is oj c: - - ::s o..t;j 0 c: oj 0.. ;'§. ;:;S2,2,2,<~OZ~~<~~~~~ g stream comes from the upper reaches, but ~dde~ tohe river ;:;S2,2,~o~~< <0:) the flow of the small spring feeders and of spnngs Illlt g with tt:> c: e bed. Each of these has been marked on figure 2, ~ onwill be .o~ o its estimated volume of flow on July 25, 1930. t .•.. .~ CI) ell ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 37 36 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS

s I-- I- seen that of a total flow of 26 cubic feet (0.74 cubic met - 1\ ..: per second at the mill, about 20 cubic feet per second co~e) al .Q..), :; Q) from the main stream, and six cubic feet per second froes --.. -!l1 S - - ~ o feeders. Springs are numerous throughout the region, b: •S... Q) ( ~ o.J..::, not all are permanent. .-- -i - C; •... ) ~ II. Physical and Ohemical Properties of the Wa.ter ..., -- -- c .oS.., 1. Tempera.ture 'c" ~ 8 - - •... A recording thermometer was mounted at station 2, with - .£ its bulb lying in the shade of a small log at a depth of four J I-- .L ~ ] feet (3.3 metres) on the edge of the channel zone. It was - ~ u in action almost continuously from June 13 to September 7. t ( 8 Figure 4 is an· example of one of the records. From these r- ~ CI r - graphs and the daily record of maximum and minimum air \1. g .0>.... temperature, we may draw the following conclusions: .~~ ) l- I-- J i-- a. The water reaches its maximum temperature be- (II / - .~.... tween 4.30 and 6.00 p.m. It averaged 5.30 p.m. for the week c-l o~ >. ending June 28, and 5.00 p.m. for the first week in September. L.--- ;; lQ l- I---, ....., :) On cloudy days the maximum is reached one and a half 1: - r hours earlier than on clear days. 1(0 The water drops to its minimum temperature between (\I l- I L.--- ~ - 7.00 and 9.00 a.m., averaging 7.45 in June and 8.30 in o (J) w September, on bright days. On dull days the temperature z I- i-- o I-l ~ may continue to drop until noon or even until 3.00 p.m. w - Although no definite figures are available, it is cl~ar ~ ~ i~ l- / I-- that these maxima and minima lag behind the correspondlng ~::E t-- - air temperatures. In summer the minimum air temperature ~ / o~ is reached about 5.30 a.m., and the maximum about 3.30p.rn- Ul Woz l- f-- ~ I-- Figure 5 illustrates this lag graphically. ~ - b. The factor most influential in warming the w~er ... ) ~~ I--t-- i-- during the day is the direct radiation of the sun, rather t a~ lii i the temperature of the surrounding air. This is illustrat~e / - ~z in figure 4; July 26 was the only dull day in the week:k~g I-- o~~ ~ t-- others had a sky nearly free of clouds. Even more strltur l~s :l: - is figure 6A, in which maximum air and water tempera ECOLOGICAL CLASSIFICATION OF 0 TARIO STREAMS 39 38 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 2. Dissolved Oxygen are plotted together. On five different occasions the .•• temperature rose above that of the air, in one case as rnucha- The water of a river ld respect to oxygen at all ti:~su ten? to be saturated wi h 6 ~. (3.30 C.) This occurred only on dear days, whe~ t::' 0 faeto . . ' were rt not for the foUOWtIng sun s radlatlOn was strong. e rso The relation between ~inimum t~mperatu~e of air and a. Variatron in atmos h . oxygen increases with incre p .enc pressure; solubility f water, shown in figure 6B, ISless obVlOUS,but It is probable ase In pressure 0 that air temperature is more active in regulating the low extreme of water temperature than the higher. The othe< I factor tending to lower the water temperature of the riv~: 1/ / 1...- 1"--" \ , 1/ V J \ .JU \4..1•••910 \ \ I V M".D R.IVE~ " '2 '/-i- 1/ '~ \ "'-.-1 eo .,.. I.•.••..•••. /\ !/ - •• UR S '" E WT A. JW '\ ~ V r-- "TO ~ ~f ~ - M I!'" •• 5 , r-. . ""'" '" I'--, [7 <, \ ~I- ~ ~ r /\ / r-, [7 /1/ \ , " I 1/ ~ V I \ 60 - 1\ 1/ 6P~. 6.0..1-\. \ II / ~ ~=, I ~'1 ~ FIGURE 5. Daily fluctuation in temperature of air and water at the Mad river ~ .JUNE;. " 3 ••. 5.,JUle-V"7 2Z 23 Z4 25 2627 rz"--1J'3 14 15 ie 17 I 1

IGURE 6 . AUGU 4 e '" "7 .' Maximum and rni ST sePTeMBER. river J urn and minimum t .J.L.U.~ 19-.s is, of course, the influx of cold water from springs and ereet;:· , une-September, 1930 emperatures of air and water at the Mad On one occasion this was sufficient to cause a droP beloWt e b. Vari . minimum air temperature. r'J reasesn '.ation in temperature of th In winter diurnal variations in temperature are.1~e5t c. I filth Increase of tempe t e water; solubility 0 ed W slight, as shown in figure 7; 33.60 F. (0.9 C.) was the h ;in . n ux of ra ure ndgs OrP eI sewherewater. of differentoxyg . en content from temperature recorded, while for most of the day It rern at 32.0° F. (0.0° C.). ctioJl Incr.' eashoteosy n th etic. activity of reen . c. Seasonal variation in temperature in th~ se ,,,ere }t in the the amount of dissol~ed plants, wh~ch tends presence of the sun's r di . oxygen; thIS occurs near stations 3 and 5 is shown in table 6.The readIngs a ration taken on a bright day, usually at 3.30 p.m. 40 ECOLOGICAL CLASSIFICATIO OF 0 TARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STRE;AMS 41 e. Respiratory activity of plants and animals of all variation of the oxygen content of the water in A h i h . bl 7 . ugust and sorts, which tends to decrea~e the amour:t of dissolved Marc ISsown in ta. e and Illustrated in figures 7 and 8 oxygen; this continues at all times, but dunng the day its In summ.er the time of maximum oxygen content follo~s that of maximum temperature by about two h . effect upon the oxygen content of the wate.r may be obscured 'l h . ours, ~ e at. 8 00 p.m., whlet e time of minimum oxygen .. by the reverse process, plant phot.osynthesis. · content occurs ab out tr hee hours earlier than the minimu t Where water is in contact with the atmosphere, there is "· m em- perat ure, at 5 .00 a.m. It IS interesting also to note that TABLE7. Diurnal variation in water conditions of the Mad river at station 2

Temperature Oxygen Time pH. 5Cl Date OF. cell p.p.m. Per cent. °C. sat. ... 4.5 6.4 64 1930 8.30 a.m. 14.8 58.7 j,;' 16.6 61.9 ., . 5.8 8.3 86 '- r- Aug~~t 16 12.30 p.m. 6.4 9.1 101 ...- r-- I..... 5.15 p.m. 19.8 67.7 .. , 100 .- - 110 .. 8.40 p.m. 18.9 66.0 ... 7.0 10.0 1 63.4 .,. 6.0 8.6 91 OXY fsEN .. 12.30 a.m . 17.4 68 15.6 60.0 ., . 4.7 6.7 r-;;;;;;::: I--. August 17 4.30 a.m. 7.1 72 1- .. 7.15 a.m . 15.0 59.0 . .. 5.0 .. p"" ENT !sATUI ATIO 7.0 10.0 69 8.15 a.m. 0.0 32.0 7.7 1931 7.7 7.5 10.7 73 March 23 10.15 a.m. 0.2 32.5 7.7 .,. . .. , .. 21 12.30 p.m. 0.4 33.0 11.4 78 0.4 33.0 7.7 8.0 .. 22 3.40 p.m. 8.4 12.0 81 .. 5.30 p.m. 0.6 33.0 7.7 76 21 7.7 7.8 11.1 .. 22 9.35 p.m. 0.0 32.0 10.4 71 32.0 7.7 7.3 .. 12.15 a.m. 0.0 '>ATu 21 EM". '" .. 22 5.9 8.4 77 10.00 a.m. 8.4 47.2 7.3 87 7.3 6.3 9.0 April 19 2.10 p.m. 11.3 52.3 8.7 87 12.6 54.6 7.4 6.1 83 .. 5.35 p.m . 7.4 5.9 8.4 .. 8.00 p.m . 12.2 54.0 7.9 77 11.4 52.6 7.4 5.5 ~A.l1. .. 11.15 p.m . 71 IZNoo,... 6 P.M. 7.2 5.3 7.6 I2 MT GA-M. .. 6.30 a.m . 9.5 49.1 7.9 74 7.3 5.5 84 F J./...McH"gh 193" April 20 9.15 a.m. 9.8 49.7 8.6 .. 11.5 52.7 7.3 6.0 IGURE 7 FI '. .. 12.20 p.m. M~rch 2~~13~tl~31tntemperature and oxygen content of the Mad river, . h tion of these frorn 500 an exchange of gases, which counteracts t e ac t earn like \\rith . p.m. to 10.00 p.m. the water was supersaturated factors and tends toward saturatiori. In a. slow ~:ak, and in thoxygen: this reaching 110 per cent. about eight o'clock the Mad river, this process IS comparatlve~ ltb respect hOWeed evenmg'. D et ermm. a t.iIons ~a de on other occasions consequently the water is often supersatur~te w1Belo","irn- 'rly d even .hIgher supersaturation. In this slow and oxygen by day and unsaturated by night- . usuallY e weep section of the river, the principal agents in aerating to '. f fiver IS 1 portant falls or long rapids. the water 0 ad ni ht. Diurna th ater are green plants. The effect of the sun's radiation saturated with respect to oxygen both day an g e photosynthetic activity of plants becomes apparent ECOLOGICAL CLASSIFICATION OF 0 ARIOST TREAMS 43 42 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS earlier in the morning and continues later in the evening - - - than its effect on the water temperature. - r=

In winter, the processes of respiration and phot ... \ ...... \ synthesis are retarded by the low temperatures; hence the ... \ ...... \ amount of oxygen dissolved in the water varies much less ... , \ - than in summer, only between 10.0 and 12.0 parts per .>k - - ('V I ---~ T 'Zoo \ - z o \ 0 w 1---, CD ~ C! (\I 150 cl J ::l \ ~ I II V r • u ./ ~ Q.. ., ~ / ~ I I 1- 0 f- Z I N Ul 0/ LY' " 100 ~ e, 1- ~ 10 ./ V 0 o < 0 (II ::z::- 0. Z I"- / t-, 1- PARTS PI! MIU.tOM ~ ::!- so < .::.,l ~ ./ V -, g •o..S. OJ ° '\ -- 0. 1/ ./" E <' .OJ., V o ,...... > _0 1 _____ / "- 6/1.·M. l..--"" ~ IZ.Noor< 6 P·M. JL.McHugh /933 ::l I-- (' 19 :J CDJ V ") ""'~ (" million. The peak is reached about 6.00 p.rn., and the I--. , III minimum probably about 7.00 a.m. . Z t--~ "~ OJ The seasonal variation in oxygen content isdi showS wn e111re 'If ., f h 1- table 6 and figure 9. Most, but not all, 0 t e rea ing .' s t--~ J taken about 3.00 p.m., and when varying weather condlt~Ons ~ are taken into account, it is obvious that these detern:inat~~~h ~ o 0 C!l

0 E 0 0 •0....• 0 0 0 6. Hydrogen-ion Concentra.tion :ll Ii 0 i2 0 CQ ..•. &; OJ C'I C'I C'I •....• •....• •....• •s....• c d, "- t!i C'I C'I "1:l •.. ",0. Greenfield (1920) has shown that the carbon dio id 03 0. 03 • 10 10 ::r:: 00- c;i content, acid carbonate content, and hydrogen-ion xi e •.•'"0 •....• to to to to r-: ..•. ..•. . f con- 0'0'" •....• •....• ,..., ..... "•....- • 0> centration 0 natural waters are connected by the followin -ur-dd (tOJ) 10 •....• ap!xo!p I c;i "- C'I ..•. formula: g c6 0 c;i •....• r-: r-: uoqreo aal!i. 0 ~ (H+) =4.0XC02XlO-7 +1 X10-8 (tOJ)/ a~lmoqleJ 0 0 0 (HCO;) 0 0 0 . 0 0 0 leWlON where (H+) is the hydrogen-ion concentration, in grammes (tOJH)/ CQ a~lmoqllP ~ 0 00 0> 10 per litre, CO2 is the carbon dioxide content, expressed as 0> 00"- 0"-> C'I 00 P!:)V •....• •....• •....• •8....• •....• ..... •....• 00•"-....• .CQ.... parts per million of C02, (HCO;) is the bicarbonate content "-

3• •....• ..... (or "alkalinity") expressed as parts per million of CaC0 CQ C'I ..•...... •....• 0> 0 "-r-- 00 00 •....• CQ ..•. This relationship he has more conveniently expressed in the I"~'~ ~m./ S •....• "- ..... 10 form of a nomogram published by Shelford (1925). From 0 ..•. ..•. CQ •....• 0> >~. /0 ~ . 1 C.'I ><. •.•.• 6 0 00 co co •....• c"-6 "- these calculations we may deduce that: o 0. •...• •....• •....• ..... ~ to

(1) the pH of a river will decrease (become more acid) ..•. 0 0> 0> 00 00 ..•. r-: L? .0 .0 r-: "- with increase in carbon dioxide content; I~s I: "- C'I CQ ~ (2) the pH of a river will increase (become more al- 00 CQ ..•. CQ ..... •....• :r: r-: "- r-: 0 C'I kaline) with increase in bicarbonate content; 0. I~ "- "- r-: co r-: r-: r-: (3) if the pH of a river is greater than 8.0 it contains 10 C'I 0 10 10 10 10 no free carbon dioxide; ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ (4) if the pH of a river is less than 8.0, it in all prob- o 00 0 10 C'I 0 0 10 10 00 ability contains some free carbon dioxide. (Free mineral ~ ~ 0 00 ~ ~ ~ ~ ~ ~ acids have the same effect, but are not found in unpolluted waters.) The large proportion of acid carbonate in the Mad river is responsible for the rather low hydrogen-ion con- e centrations (high pH) recorded throughout the year (tabi ) 6,, 7 8). In summer the pH ranged from 7.8 to. (raren Yd s 8.0, but did not exceed that figure, as it often does. Ing wt p?nter (Ricker, 1932b). The lesser values recor ded dunn It (7.5 in January and 7.7 in March) are prob~bty. the re~~h of an increased carbon dioxide content at this time. "'! '~y in turn is the result of the decreased photosynt?etic aC~Vlth~ as explained above. At the time of the spring floo , the alkalinity of the water is cut in half, and the pH has correspondingly low value of 7.4. ECOLOGICAL CLASSIFICATIO OFN0 TARIO STREAMS 49 48 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS and very noticeably during the spawni Diurnal variations in pH could not be certainly det a temperature reaction. Gammarus w~g se~s~n-pr~bably during the summer nor in March, owing to the buffer ae~c ~ed Mad rive.r, nor. ye.t in its tributary' Do g swooood croeekunde III the of the acid carbonate. In April, when the last named ion in one sltuatlOn in each stream wh . ,xcept less abundant, the pH rose to 7.4 during the day and ~~~ coming up from below. ,ere spring water was to 7.2 at night. e It may be noted here that the author has found very close agreement with Greenfield's formula in the C~o III. Aquatic Vegetation HC0 , and pH determinations he has made, owing perha 2, 3 to faulty technique in titrating for carbon dioxide. The 1. Emergent Littoral Plants figures given for carbon dioxide concentration in table ; In some places, typical woodland should be compared only among themselves. extends down to the bank of the ri or pasture flora - e river and grves once to the aquatic forms Usua 11 h way at 6. Springs area is marked by a distin~t litt f' o~ev.er, the shore some of which are partly sub ora association of plants, Springs are somewhat different from the main stream in during high water only Th merged at all seasons, some the physical and chemical properties of their waters. They . . e more Important i d f therr occurrence from the I d ' n or er 0 probably show no significant diurnal variation in these follows. (The letter followin~nth toward the water, are as respects. The peculiar characteristics of spring water as how common was its occurren . A na~e of a plant indicates compared with the river would seem to be: temperature O--occasional, R-rar . d ceo . a undant, F-frequent, low and nearly constant at about 6.50 c., low oxygen content Mr. R. F. Cain of thee'IUn. esce.ndmg order of magnitude.) i ki ' nrversrty of Toront h . of about four parts per million, low pH-7.1, and a high n ma ng the determinations. 0, as assisted carbon dioxide content. As the water flows away from the Cornus stolonifera. A. spring, it quickly gains oxygen, and more slowly loses carbon Myrica Gale. A the com dioxide and rises in temperature. Many springs, however, region. Like ~he I?one.st plant of the shore have an oxygen content much higher than the above, some- at the wat ' d preceding, It forms dense tangles er s e ge. times as much as ten parts per million. Seasonal variatio?, Carex spp F' . in the case of B. N. spring (figure 2) was evident chiefly 1U in the ;'b' vanous species of sedge are abundant eaver meadow" but f d temperature and carbon dioxide content, as shown in table 8. scattered patch I h are oun only in The temperature was lowest in April at the time of the Phal . es e sew ere. arts arundinacea 0 f floods, and the highest recorded was during the winter. ~~ grass" t i ., orms clumps of "marsh readings were taken at midsummer, however. It wo~ stream~ intervals along the lower stretches of the . . h . lowenng seem that m spring the flood waters enter t e spnng, s Eleocharis s R f . .' . t t nd decrea - or Carex pp, , ound rarelyas an outlier of Phalaris Its temperature, increasmg Its oxygen con en , ads e ing its carbon dioxide content, alkalinity, and har n :h: 1'b The above '1 The effect of this admixture does not last more than a mar-ar- theOSe to follow ~~~s "Y~e subm:rged only in the spring. Some animals appear to be susceptible to the pec~~er_ summer. Wit stems III the water throughout ities of spring water. Trout congregate on the. three rnr~er, Equisetium fluviatile R bed springs of the Mad river to some extent during su • . , seen commonly near station 8. I I 50 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONT ARlO STREAMS 51 Sparganium sp. R, the emergent form of this reed Potamogeton natans. R was not common. Sparganium sp. F. . Sagittaria latifolia. O. Sagitta ria sp. O. Radicula nasturtium-aquaticum. 0, common in s Potamogeton amplifolius F parts of the beaver meadow section. It m~~e These five were characteri~tic . f t equally well be classified with the true aqu gt't Their roots did not collect mud a~ d?e marl of the channel. "I a~ that the water flowed through them id the ab?ve forms, so pants. The first three were alrno t fi comparatIyely rapidly station 5; the last two we:e CIon ned ~o the reaches abov~ 2. True Aquatic Plants below. Bo~h the Sparganiu~ s~n~eet~In th~ slo~er reaches About nine-tenths of the total bottom area of the of the typical upright form bu e Sr:g'tttana were not leaves which waved in th' t had linear and flexibl stream provided anchorage for various sorts of aquatics. bod' decurrent Ab e The bare tenth was of three types: (a) parts of the channel res ma e specific determin ti . . .sence of fruiting Mosses. Submerged I a IOn impossibls. marl; (b) muddy borders where the plants were killed by ogs were ofte summer fluctuations in water-level; and (c) deeper mud mosses, especially if the t d n covered with banks whose vegetation had been washed away by the spring Algae. No particular stul s 00 out from the bottom bution of algae other tha~ C~as made of the distri~ floods. Plants of the mud flats forms occasionally attract d nr . Large filamentous Nymphaea advena. A, although perhaps strictly speak- and, with diatoms app e. nh°tIce on the bottom , ear In t e food of some fish: ing an emergent species, this is characteristic of the zone of true aquatics. It was the most abundant plant of the mud flats in the slower parts of the IV. Aquatic Invertebrates nver. 1. List of Species Chara sp. A, grew in all situations up to a depth of five or six feet (two metres): common in all parts Tubificid . Oligochaeta of the river. It apparently gives way to the more L. ae. Occasional. umbnculidae R deeply rooted Nymphaea. . are. Ranunculus circonatus (?). 0, the white water-crowfoot resembled Chara in habit but was much less lIelobd II Hirudinea common. GlossiPhoe a sta. gnalis (L).. 0ccasio .nal There was a reciprocal relation between the distribution At, ma complanat (L) . ? acrobdellad (a.. Occasional of the last two plants, and the muddiness of the bottornci lIaemopis ecora Say). Rare. . While the plants preferred a soft substratum, their tangl~ lIaemopis p7ua;'/!:e0ratis(Say). Occasional. stems were themselves efficient collectors of silt, so that t e us Moore. Frequent. muddy areas encroached upon the comparatively bare marl. Clado Crustacea Plants of the central channel cbera, Cop epod a, and Ostracoda . ut were not studied s t ?ccurred In abundance Hippuris vulgaris. O. ys ernatically. ' F ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STRE,AMS CLASSIFICATION 0 53 52 ECOLOGICAL Zygoptera d ) Frequent. Ischnura verticalis (Say). Rare. Amphi~y:Zella knickerbockerii (Bate . Enallagma ebrium (Hagen). Rare. d . d Frequent. The food Enallagma boreale (Selys). DecapoC ambarus propinquus GI.r~rd· chiefly of fragments of Agrion aequabile (Say). Occasional. a f five specimens c~nsis e diatoms and other Agrion maculatum Beauvois. Rare. o 1 ts wIth some vascular p an Baetid nymph. Anisoptera algae, and one Rare. Aeshna umbrosa Walker. Rare. C. bartonii robustus. Tetragoneuria spinigera Say. Rare. Somatochlora minor (Calvert). Rare. Insecta h were identified Neuroptera Imagos and n~mp.s of Toronto. Ephemeroptera. Ide of the Umversity Sialis sp. Frequent. by Mr. F. P. Chauliodes sp. Rare. Ephemeridae .. Occasional. Th Trichoptera. Larvae were identified with the aid of Hexagenia v~ndescens.. lans Abundant. e Lloyd (1921), Lestage (1921), and Needham and cf s~mu· . taken Ephemera sp, . 1 f seven specImens, d Needham (1930). Dr. Cornelius Betten of Cornell 1· ntary cana so. ed much sane, a ime b contain 1 t University has identified the imagos collected. M to Novem er, f vascular p an s, Hydroptilidae ay b. fragments 0 organic de .rIS, d filamentous algae. Hydroptila sp. Rare. and a few dIatoms an Hydropsychidae. Collected rarely in the stony section. Baetidae . llis Occasional. Polycentropidae LePtophleb~.amoilis· Rare. Neureclipsis sp. Occasional. The loose nets of LePtophleb~adeb . Abundant. this species were commonly seen trailing from Blasturus nebulosus. l· Frequent. Ephemerella tempora is. logs in a moderate to slow current. . Frequent. ?Polycentropus spp. Occasional. Three species of Caems sp. Occasional. larvae which appear to fall into this genus'were Rare. Baetis pygmaeus. xum found in the stream, on marl or stony bottom. Centropti.lum ~°7z~m. Rare. Centrophlum e Plectrocnemia canadensis Bks. Imagos, 12. vi. 30. Chloeon sp. Rare. Plectrocnemia sp. 8. Imagos, 27. vii. 30. The larvae referred to Polycentropus may belong Heptagenidae Frequent. here. SiPhlonurutsiPs~~ctata. Freq~ent·l Phylocentropus sp. Frequent. Imagos, P. placidus Ecdyurus r . OccaslOna. Bks., 8-12. vi. 30. Ecdyurus canadens~s. up). Rare. (fusca gro Lype sp. Imago only, 7. vi. 30. Ecdyurus .sp. Rare. . by pr. Sericostomatidae H ptagema hebe. identlfied Goera sp. Rare. e d ymphs were f T ronto. Lepidostoma sp. Rare. Odonata. E~~~~at:er :r the University 0 0 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 55 54 Helicopsyche borealis Hagen. Frequent. Imag lIeteroptera. Corixidae have been identified by Mr. .. 30 os, G. Stuart Walley, of the Entomological Branch, 2-7 . vu. . Ottawa. Molannidae Corixidae Molanna sp.Occasional. Imago, M. cinerea Palmacorixa nana Walley. Frequent. Hagen, 17. vi. 30. Arctocorixa modesta Abb. Occasional. Leptoceridae Arctocorixa vulgaris Hungfd. Occasional. Leptocerus sp. Imagos only, 12-13. vi. 30. Belostomidae Oecetissp. Occasional. Imago, Oe. incerta, 8.vii.30. Benacus griseus. Rare. Triaenodes sp. Occasional. Imagos, 12. vii. 30. Nepidae Mystacides sepulchralis Walker. Abundant. Im- Ranatra americana. Rare. agos, 8. vii.-14. viii. 30. Nepa apiculata. Rare. Phryganeidae. Larvae of two species were occasional Gerridae in early spring, and common in trout stomachs. Gerris sp. Occasional. The food of four specimens was chiefly of Diptera. Larvae of Chironomidae were identified by matter: Chironomine larvae and a Hydroptilid Dr. O. A.Johannsen of Cornell University, imagos caddis larva, with about 15 per cent. vegetable of Tabanidae and Empididae by Dr. C. H. Curran, debris. of the American Museum of Natural History. Imagos, Ptilostomis sp., 15. vi. 30; P. semijasciata, Tipulidae Antocha sp. Rare. 12. vi. 30; Phryganea? sayi~ Ceratopogonidae Limnephilidae. Many of the larvae taken could not Culicoides sp. Frequent. be identified even as far as genus. Chironomidae Limnephilus indivisus. Imagos, 12-23. vi. 30. Tanypinae Larvae of this species were abundant in April Pentaneura (Ablabesmyia) group flavifrons. in temporary pools, and may occur in the river Pentaneura (Ablabesmyia) group monilis. itself. Procladius group adumbratus. Limnephilus sp. 34. Imagos, 5. ix. 30. A common Clinotanypus. cross-stick larva of the river is probably to Chironominae be referred to this species. Chironomus subgenus Cryptochironomus. Rheophylax submonilijer. Imago, 8. vii. 30. Chironomus subgenus Microtendipes. A nabolia bimaculata. Imago, 4. viii. 30. Chironomus subgenus Endochironomus. Halesus guttijer. Imagos, 5. ix. 30. Larvae f.re- Tanytarsus. Simuliidae quent; many specimens hav~ the dorsa.l spac~~g hump partially or wholly illverted, ill W~l1as Simulium sp. Occasional. s Tabanidae case they resemble Stenophylax scabripenm Chrysops indus O.S. described by Lloyd (1921). Chrysops carbonarius Walker. Neophylax sp. d. autumnus. Larvae rare.

II! ON OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 5 56 ECOLOGICAL CLASSIFICATI Planorbidae Larvae 0f Chrysops were rare. Helisoma trivolvis (Say). Rare. Empididae .' regularis Loew. Imagos Were Gyrauius parvus (Say). Frequent. Rhamphomy'ta 'tr in May, swarming close to Gyraulus deflectus (Say). Rare. rather common 1 Ancylidae the water. hi der were determined by Ferissia rivularis (Say). Rare. of t 1S or . 1 B h C 1 ptera. Imagos f the Entomologica rane, Ferissia parallela (Haldeman). Rare. o eo Mr. W. J. Brown, 0 Pelycypoda. The Sphaeriidae have been determined Ottawa. by Dr. V. Sterki, of New Philadelphia, Ohio. Halipli~ae . maculicoUis Harr. Rare. Pisidium compressum Say. Frequent. Hal'tplus im. Pisidium variable Prime. Frequent. Dytiscidae Fab Occasional. Pisidium sargenti Sterki. Occasional. Hydroporus dep:ess~s Sh~rp. Occasional. Hydroporus sol'ttanus Pisidium sp. (near sargenti). Frequent. Pisidium sp. Occasional. Gyrinid.ae sp Rare. Larva taken. Musculium sp. (immature).Rare. Gyrmh~l:d . Rare. Sphaerium rhomboideum (Say). Frequent. Hydrop 11 ae. HI' dae Occasional. e ~~lmis quadrinotatus Say. 2. Ecological Distribution of Invertebrates Chrysomelidae. Kby Rare. The distribution of the invertebrates in the above list . p oxima. . Donacw ~ . U' Kby Rare. will be discussed, by a reference to typical habitats. Unless Donacia h'trt'tCOis R' otherwise indicated, records of insects are based on immature '11 S yare. Donacia pus: a a. ltages. The unit of bottom studied was 144 square inches (929 square cm.). As explained above, abundant species Arachnida . 11 collected are ~epresented by 16 or more examples in that area, frequent . were occaSlOna Y .Water mites . ttention. Cles by 6 to 15 examples, occasional species by two to Hydracanna. . d no systemat1c a \"e and rare species by only one. but have receive 'lore region. Mollusca of Toronto, .FRLatchford, flt .(a) Among the grass along the shore (Phalaris Chi f Just1ce .' . Gastropoda. 1e. d most of the speCIes. knd'tnacea); depth of water 0 to 4 inches. From June has determme 91o~nuary this region was dry. One col1ection: May 20, Valvatidae . . ta (Say). Frequent. Valvata incarvno bundant forms Amnicolidae. (Say). Rare. •.•••.. A.rctocorixa adults and nymphs of Palmacorixa. ?Amnicola l'tmosa -'{Uent forms Lyr~maeidae alis L. Rare. EPhemerella temporalis, Siphlonurus sp., Limnephilid Lymnaea stagn (Say) Rare. B. Stagnicola caperato . 58 ECOLOGICAL CLASSIFICATION OFONTARIOSTREAMS ECOLOGICALCLASSIFICATI ON OF ONTARIO S . • TREAMS 59 Chlronor~lldae. Procladius Occasional forms occasional in May d (adumbratus group) Limnephilid C, Chrysops, Culicoides, Stagnicola. they were evidently' aabn abundant in June where D b d out to pup t ' w en Rare forms a un ant in May a e. Chiron . Oligochaeta,Helobdella stagnalis, Hyalella knicke_ Sphaeriidae. Pisidiu . ornme A, bockerii, Halesus guttijer, Limnephilid Pe:. Frequent forms m was abundant at both tim taneura (group flavijrons), four species of Chiro. C 1" 0d es. nominae, Haliplus immaculicollis, Lymnaea stag- u tcoi es. Frequent' M Clinotanypus A (pi !n ay and June. nalis (immature), Gyraulus deflectus, Pisidium. ngtas group) I (b) Mud bottom, near shore, partly covered by leaves read y to pupate . n June sorn Occasional forms' e were grass stems, and small sticks; depth 0 to 3 inches. One HyaleUa knickerbock .. collection: June 17, 1930. in May. en~ was occasional in June ab Occasional forms Corixidae, Chrysops, Chironominae,Culicoides, Halesus guttifer. Two' ' sent Arctocorixa sp 0 .specimens taken in M Pisidium. Tanypine c.' ccasional in May. ay. Rare forms Oligochaeta, Macrobdella decora,Haemopis plumbeus, Chironomine NO' Chironomus (E d h~casIOnal in May. Helobdella stagnalis, Limnephilid E, Stagnicola, Ch' n oc tronomusj A 0 Gyraulus parvus, Helmis sp. lron?mine sp.? . ccasional in Ma Sphaenum rhomboide y. Mud-Nymphaea region. Bottom of mud in which are Rare forms um. buried the fleshy stems of Nymphaea, the leaves of which Oligochaeta E chral' ' phemera d. simulan M . appear early in spring, and reach the surface in June. Three G ~hsP, hylocentropus sp S ° l~' ystactdes sepul: series of collections were made in this important section: ,ot er Tannvypmani s and Chi., ui ts sp ." Climotanypus lronommae M. at depths of one, one and a half, and two feet, referred to (b) D ' usculium, the standard May level. By June 25 the water had fallen so that the first of these was at times quite dry, the second, lbinirnurn epth 18 inches in Ma barely under water. These fluctuations caused considerable f~ly 4, J UI~f2~n~ inch. COllect~n~Ut~~ate;,;n summer to a . ' ugust 12, September 4 ~ bay 21, June 9, destruction of life; the following species were noted dead o~ undan t f ' cto er 20, J an uary the bottom, presumably killed by desiccation: HaemOP~os b orms marmoratis, Halesus guttijer, Lymnaea stagnalis,Planorb~s Palmaconxa. nana N freque t . . yrnphs freq . trivol(a)vis. Depth one foot in May, dry in summer. Collections Culicoidesn ~ June and abundan~e?t 10 May, adults at othe . bundant in May 10 early July. taken May 20 and June 18. Clinota er tImes. and June, occasional nypUs A (p' . Abundant forms 'n and fre . mgu~s group). Ab . Chiron .quent 10 May and J undant III winter Corixidae. Nymphs of Palmacorixa were frequen~~t omme Q une. ' May; in June the nymphs had disappeared, other tiirnes. . Abundant inwint . er, not found at adults of P. nana were abundant. 60 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS Pisidium. Abundant in May and June, frequent at 61 other times. Rare forms.. '. Frequent forms .. '. Lumbncu~Ida~, .Gloss1,Phoma complanata, Dina parva?, Hyalella knickerbockerii. Frequent In WInter and earl Hexagema. v1,Y'/,descens,Baetis Pygmaeus, Mystacides spring; occasional or rare at ot her tI.me~.H y sepulchraiis, Halesus guttijer, Limnephilid B Ephemera d. simulans. Of ~cattered dlstn~ution in Ph.ryganea sp., Pentaneura E. (group flavijrons): the silt beds; abundant In some collectIons and C.hnotanypus G, other TanYPInae, Helmis quad- rare in others. rinotatus, Hydroporus solitarius,Hydroporus de- Phylocentropus sp. Pupae taken up to early June; pressus, Sphaerium rhomboideum. young larvae first appear. late in J ul.y, and are occasional to frequent until the folloWIng June. (c) Depth 24 inches in May, minimum summer level Clinotanypus A (pinguis group). Abundant in winter, six inches. Collections made on May 20, June 14, July 5, frequent in May and June. July 27, August 13, September 4, October 20, January 17. Clinotanypus H. Frequent to rare from early July Abundant forms to October. Procladius B (adumbratus group). Mostly occasional Phyloc~ntropus sp. !'requent to abundant, except or rare, but abundant in early July. . . dun~g emergence In June and early July. Chironomus (Microtendipes) 1. Abundant In winter, Arctocor1,xa modesta. Abundant in late summer and fall. not found again. Chironomine Q. Abundant in winter, not found Procladius B (adumbratus group).Occasional in again. spring, abundant in summer and fall. Frequent forms Occasional forms Tubificidae. Usually occur.. h t Hyalella knickerbockerii. Frequent in summer and Haemopis plumbeus. Occasional or rare throug ou ~all.' occasional in winter and spring. the year. abun- Cu.hco1,des. Frequent or occasional, except in June. Sialis sp. Usually rare, but small larvae were Chnotanypus A (group pinguis). Frequent in May and June. dant early in September. . . absent at Cl" Blasturus nebulosus. Frequent In WInter, T znot~nypUS H. Frequent during July and August. other times. b r a?YPIne.c. Frequent from September to spring. Arctocorixa modesta. September and Oct~ e ~ernber, ChirOnomInae. Several small species frequent in . ~ertain dredgings. Tanypine C. Absent from late July to ep P1,s1,dium 0 . I.. occasional at other times. . I in MaY .' ccasiona In spnng, frequent from summer Occ' to WInter. Chironomus (Endochironomus) A. OccasIOna aSIonal forms and June.. Occasional frorn rnoPi Chironomus (Cryptoch1,ronomus) B. iJ:: : PI'll:rr:beus. Occasional or rare. a~en1,a v1,Y'/,descens. Of scattered distribution In May to early July. . d occasion- thIs area. Chironominae.Several small species !oun E ally or rarely in some of the collections. Phernera d. sirnulans. Commoner than the last, but equally irregular in appearance. ECOLOGI.CAL CLASSIFICAT ION OF 0 TARIO S TREAMS 63

62 ECOLOGICAL CLASSIFICATION OF 0 TARIO STREAMS beds, appear in the collections In h the large caddis larvae such a' R / e first class are included Sialis..sp. Usually occasional in occurrence' fr equent C and D, Phryganea A, and s als~ esus g~ttifer~ Limnephilids in winter- Ephemerella temporalis Chr p Glossiphonia complanat .I d TT yso s sp et W a,s Arctocorixa sp. This spring form was occasional' IOCu e va 1vata tricarinata.' G l" c. eed-bed form June. in tela. Baetis pygmaeus, Helmis s;a;'[u; parous, Ferissia parol Y Palmocorixa nana. Occasional in June. while Mystacides sepulchralis ., d Cropo~usspp., and others Sphaerium rhomboideum. Frequent to absent. . th 1 an aems ' orne m e mar gravel of the d eeper water.sp. are morea t Musculium sp. Occasional or absent. h Mu~dy :veed-bed region. The . Rare foTu?rmsificidae, Glo.ssiphonia complanata, Cambarus pro- effiCIent in trapping silt amon th etwo aquatic plants most p~nquuS, Caems sp., Ephemerella temporalis, Agrion and Ranunculus. Of these CKara :tems and roots are Cham aequabile, Halesus guttifer,Limnephilid C, Lim- ~t grew at depths from six feet as much the commoner Its stems were killed fro up to water so shallow th . nephilid D, Phryganeid A, Chironomus (Micro- Th m exposure t . at tendipes) I, Chironomus (Cryptochironomus) B e most extensi. ve beds were at a d0 hair during sum mer. Chirono (Endochironomus) A, Chrysops sp.', o ree eet in May. ept of one and a half mus t th f Helmis sp., Valvata tricarinata, Helisoma trivolvis (a) Cham beds Colle ti May 21, June 9, J ~l 4 / IOns were made at station 2 (young), Ferissia parallela. ~to~r 20, and J an';'r; 1~l:n~' August 12, September ':;' Summary of the mud-Nymphaea section. This region is e ocation was near mid~ one on July 3 at station 8' characterized chiefly by the abundance of : ches, or 14 to 32 inches ref::;:~m, at a depth of 6 to 24 Chironominae in shallower water and Tanypinae in deeper bundant forms to the May standard. water, with Culicoides throughout. Corixidae are common Culicoides. . Ab und ant from M at moderate depths, with three different species reaching Ch.occasl~nal at other times ay to early July, peaks of abundance about June 1, July 1, and september 15 ironomm. e D.IThiS small . b respectively.The abundant caddis is Phylocentropus, which norrunae was abundant f mem er of the Chiro builds its branching mud tubes in the deeper water. Among . id~H~tabsent thereafter rom May to early July- mayflies, Hexag viridescens and Ephemera d. sim.la'~ enia u Pis tacm. Abundant . form scattered colonies; Blast.rus nebulos s is frequent rn l'equent ffall and winter. up to September, but rare in winter. HyoleUa knickerbockerii is a frequent species 0c- orms curring in fairly constant numbers. Clams were commooes n; rat HTuaembificidaen . . Frequent from Ma sphaerium rhombaideum in deep water, and several spe 0 P'ts plumbeus. Freq y to July, rare later. pisidium in shallow water, though the latter may mig : out. uent or occasional th h outward during the summer drought. The large HeIronom~iPes) d: iUlico~des sp., Clinotanypus A (pinguis group), nominae not me u C~ironomus (M~croten or'U ! s anYPlne C, two small Chironominae, Tanytarsus tochironomus) C!"crotendiPes) I, Hydr0fricari1Iot, sP., HYdroPorus depressus, SPhaerium rhomboideum. Chironomus ~ . sp Valvata pressus,. Muscul?ium ., A mnieola limnosa .. ""'ry of muddy Weed beds. The fauna of these weed II ltlay be divided into two parts: (1) those animals 66 EcOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 67 living on or among the stems and leaves of the plant (2) those living on or in the mud below. In the firs:' fnd feet respectively. Only the series from the lesser depth has may be included Triaenodes sp., Helmis quadrino~tss been examined in detail, but the other appears to be es- Arctocorixa sp., Chironornine D., Chironomine M, HYdrop Us, sentially the same. spp., Va1 vata tricarina.. ta, an d Gyrau1 us parvus. Thorus Shallow series: collections were made on May 21, June 9, frequenting the mud include the Oligochaetes and leechose July 4, July 26, August 12, September 4, October 20, and January 17. HyaleUa, Cambarus propinquus, Blasturus nebulosus P:s, locentropus sp., various Limnephilids, Culicoides, Pro~ladi;~ Abundant forms B (adumbratus group) and other Tanypines, the lar Chironomines, and the Sphaeriidae. ge Ephemera cf. simulans. Extraordinarily abundant in The striking feature of the association is the large spring and early summer; as many as 250 have number of crayfish present; among these plants they find been taken per square foot. From September to shelter denied to them elsewhere in the stream. Next in June both generations occur. bulk come the leeches, chiefly Haemopis piumbeus, which Frequent forms are likewise of common occurrence. The burrowing mayflies Caenis sp. Commonest in September. are almost entirely absent; they seem to avoid loose silt. Mystacides sepulchralis. Larvae September to July, Among caddis, the interesting Triaenodes seems peculiar emerging throughout the summer. to this habitat; Oecetis and certain Limnephilids also occur. Helicopsyche sp. May to September. Midges are chiefly represented by the abundant Culicoides, Penteneura E (flavijrons group). October to June. a frequent Tanypine (Procladius), and a small Chironomine Chironomus (Microtendipes) G. January to May. which probably lives on the surface of the weeds; other forms Occasional forms are commoner on the surrounding bare mud. The diving Hyalella knickerbockerii. Frequent to absent. beetles Hydroporus solitarius and H. depressus, while abundant Sialis sp. nowhere in the stream, were commonest in this association; Molanna sp. Of regular occurrence throughout the Helmis quadrinotatus was occasional. Sphaeriidae, especially year. Pisidium, were present in good numbers. Oecetissp. Larvae in May, pupae in June. The above remarks apply chiefly to Cham. The principal differences noted in the Ranunculus were a much Chironomus (Microtendipes) 1. Frequent in October. Chironomine Q. January only. greater abundance of Arctocorixa sp. among the stems', the SmalI Chironominae. presence of larvae and pupae of Donacia sp., and the larger Rare forms numbers of leaf-living gastropods Valvata tricarinata and Gyraulus parvus. Tubijicidae, Haemopis plumbeus, Hexagenia viridescens, Ecdyonurus tripunctata, Agrion aequabile, Poly- Bare marl region. Typically the channel of the river had d centropus B, Halesus guttijer, Arctocorixa sp., te Procladius B (adumbratus group), Pentaneura I bottom of bare marl-gravel, with a few small lime-encrus ts sticks. In places it was grown up with ribbon-leaved plan e (rnonilis group), Tanypine C, Chironomus (En- . wer such as Sparganium (see below). Two senes n dochironornus) A, Chironomus (Endochironomus) collected in this area, at standard depths of four and seve H, lIelrnis quadrinotatus, Pisidium sp., Sphaerium rhornboideum, Gyraulus parvus. 68 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION 0 Summary oj bare marl region. The outstanding featur OF NTARIO STREAMS 69 this habitat is the relatively enormous number of ny; ~f their abundance, e.g. Haemopis 1 b of Ephemera, which constitute over 95 per cent. of its fa P s Procladius B (adumbratus groupp)ump~U.ds,.Blasturus nebulosus ' 'tS't 'tum t ' 4.B ecause 0f accumul ti , e c. by bulk. Caenis was the only other common mayfly. ~~a a Ion of 10 '1 characteristic caddis larvae bore cases made of sand grain e othel~way, they provide a less fa bi ose si t or in some . voura e hab't f Molanna, Helicopsyche, and Oecetis; the beautiful Mystacid s, th e samef auna, which accordin I I at or others of Ephemera, most Tanypinae gdY are .rare Or absent e g sepulchralis used small bits of wood; Polycentropus had no ,an ChI . ,.. t portable case. The Chironomoids were poor in species and i~ un roPus. ronommae , Ph y I0- individuals. Pentaneura E (groupfiavijrons) and Chironomus In the case of Sparganium '. Potamogeton natans the fi t ,Sag'tttana, Hippuris d (Microtendipes) G were characteristic, but not abundant; the d r i ' rs two effe t ' an latter used stones for its case also. A fair number of strag- ob serve ; In the case of Cbara a c s were the only ones were also apparent. nd Ranunculus the last t glers from other habitats completed the fauna. I dd" wo . n a ItIOn, certain facts of . . Marl weed beds. The plants of the marly bottom were plained by any of the f . dlstnbution are not C ixid Our mfiu Ii ex- usually long and slender, and did not collect mud among onxi ae are rarely found' Ch ences Isted above e &nunculus In era, but do not bi .g. their stems. The most typical were aquatic forms of . a ]ect to Sparganium and Sagittaria, and Potamogeton amplifolius. Unfortunately little collecting was done in this area. 3, Seasonal Variati . (a) Sparganium. A single collection on July 3 at on In Invertebrate L'f station 8 revealed the presence of the common marl organisms, .. From this point of . I e including abundant Ephemera nymphs, and a caddis not VIded into (1) those whvI·clehwf'bottomorganisms may be are t' or a co id found at the lower station; Goera sp. Valvata tricarinata fairly no m the water, and (2) th nSI e~able part of the and Perlinella? were probably from the leaves of the plant. most c?nstant numbers throu hose w ich are present equIvalent to di idi g out the year Thi (b) Potamogeton amplifolius. Collections from among er organis IVI mg them into (1)" IS IS the leaves and stems on September 4 revealed occasional Th ms. msects, and (2) nymphs of Agrion aequabile. Ii e second grou . I gochaeta H' . p IS ess numerouS d 1 • haeriidae' Irudmea, Crustacea C ~n. ess Important. ' and Cast d ,onxldae D ti . Summary of weed beds. Observations upon the "weeds" these th C '. ropo a are the pri ,y Iscldae, of the Mad river show that submerged aquatic plants may !lot un~fo~nxldae, although almo;~:~::~l representatives . affect stream life directly in four ways: t . es followsmly common throughout th ned to the water, 1. They harbour a few animals which cling closely d 0 der, on] another in a series of w e year, but one their leaves or stems, and feed there, e.g. small gastropo 5, ~oPis Plu~b two. species, Cambarus aves .. Of the re- ue. eus, are common in th f proPinquus and Helmis and probably certain Chironomines. e5t 2. They harbour some animals which merely b r The 0 e ood of the speckled tlS ted CCurrence f . among the foliage, e.g.Triaenodes, Arctocorixa sp., Casn or te by th f a most Insects in th propinquus. orne r; Fro e act that they live thei e stream is inter- 3. They provide more sheltered situations fflies, emerge during May and June and members of the mud-flat f' Phryganeldae T. ddi J auna are th . yPlcal are hence absent from the stream in July. The large Li~_ th e ca IS Phylocentropus S h " e mayfly Blastur nephilid caddis emerge in the fall, but spend most of th larvae of Chironomidae T p aerudae, and parti 1 us, standing inhabitant the' b he ~arl gravel has as cu arly summer in the dormant prepupal and pupal stages, so tha~ • I urrOWIn an out- they too are not easily found after July 1. Even the Corixids ID esser. numbers the caddo g mayfly Ephemera sepulchrahs. IS Molanna and M' ~nd are relatively uncommon by the middle of that month. ystaczdes Midsummer-J uly and August-is the time when the The total quantity of . Invertebrat Iif . life of the stream is at its lowest ebb, the only common forms year roun.d In spring th h e he ISnot const being Ephemera, Caenis, and a few Chironomids. total weight of organis e 'h ore area supports th ant the Bats are least prod t·ms, t e marl is next whi! e ghreatest Many species of invertebrates are regularly eaten by uc Ive I ' let e d fish, as is evident from tables 9 to 15. Insects are most then the mud flat .' n summer the '. mu average dry weig~~ wFI~e the shore is dry an~~l IS rIchest, readily taken, by trout at least, during the actual act of o emergence: in the case of midges the pupal state, in the case of of small shallow Ch ottom fauna is compa ~ren. The mayflies either late nymphal or sub-imaginal. Caddis flies, excess of that found' arIa ponds and lakes an~a e to that Sea I. ~n arger lakes. ' greatly in however, are usually eaten as larvae. Other vertebrates sona varIatIon' . also help to reduce the numbers of the invertebrates, e.g. ult of the e In Invertebrate Iif . during the' d mergence from the e IS chiefly the mergansers and other ducks, bitterns, sandpipers, king- rr a ult Iif A' water of . May and e. majority of th .most Insects fishers, flycatchers, swallows, bats, etc. J e Itream is at its fne, so that the inverteb sfecfles transform An . owest ebb durin su ra e auna of the 4. Summary of Invertebrate Life Uatic ~mportant biological fa gt mmer.and early fall. Invertebr t· Cor, affectI th Insecta are the most important of the larger invertebrates e~rates. In t~ es, IS their destruction ~g e numbers of in the Mad river, but Oligochaeta, Hirudinea, Crustacea, In their I' E h~ case of insects thi y fish and other Hydrachnida, Pelycypoda, and Gastropoda also occur.The Ptible du ~e Istory, but man' IS.may OCCurat any orders of insects represented are Ephemeroptera \t?ree Ubirnaginat~~gt the time of tran~f~~~Clet~are. particularly families), Odonata (four families), Neuroptera (two fam~l~es~, a e. a Ion, In the pupal Trichoptera (eight families), Heteroptera (four. ~amlhe~f 5 F' Diptera (five families), and Coleoptera (six families]- t- l'h . Ish other than Trout these, Ephemeroptera, Trichoptera, and Diptera are aU e no standing in number of species and individuals. . . tpe an' rnenc1atu S Manual oj re and systematic an The three principal types of faunal associations In ad {}e~ies have :he ~ertebrates, 13th ed~~gement is that of Mad river are (1) the shore fauna, (2) the mud-flat fau~a: ~ble l e ~ DIversity of ~en Identified by Prof ItIon. Examples of (3) the marl-gravel fauna, each of which is again drvIs Ork of the oronto. Lengths e~.:'~rJ. R. Dymond caudal fin; 1 inch =2.::::. Inches measured 72 ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS ECOLOGICAL CLASSIFICATION OF ONTARIO STREAMS 73

1. Chrosomus erythrogaster Rafinesque. Several specimen to 2.75 inches in length. Stomachs of nine specimens were taken in the stream two miles above the sectio~ taken July 12, 1928, and one taken July 25, 1930, considered here, and they may occur farther down. contained the following: 2. Margariscus margarita nachtriebi (U. Cox). The only Per cent. by volume Nymphs of Ephemera...... 16 specimen, taken July 25, was 2.75 inches long. Nymphs of Baetidae...... 20 Larvae of Chironominae...... 50 3. Semotilus atromaculatus (Mitchill). Occasionally taken Pupae of Chironominae...... 3 on a hook, and schools of young about one inch long Terrestrial insects...... 11 were seen in stony sections. It is said to have been much commoner about 20 years ago. This is very similar to the food of sculpins taken at Spawning of the creek chub takes place early in June' the same time. on June 9, 1930, two ripe males and a female extruding egg~ were taken. TABLE 9. Stomach contents of Eucalia inconstans The food of five specimens 0.88 to 1.38 inches long taken August 14, 1930, was as follows: 7 specimens 11 specimens Per cent. by volume 0.19-0.63 inches 1.00-2.06 inches Larvae of Polycentropidae...... 40 July 21, 1930 June 17- September 4, 1930 Other? caddis larvae and pupae...... 13 Larvae of Chironornidae...... 20 Entomostraca Adult terrestrial fly...... 7 11 Gastropod...... 20 Cyclops . 7 Chydorus . 7 B.osm~na . 11 1 The result of the examination of the stomachs of six Pleuroxus . 4 specimens 3.5 to 7.5 inches long taken May 17 to June 9, Ostracoda . 36 18 Hyalella knickerbockerii . 8 1930, is as follows: Insecta Per cent. by volume Nymphs of Baetidae . 5 Diatoms, fragments of vascular plants and bottom Nymphs of Corixidae . 11 ooze...... 52 Larvae of Tanypinae . 2 Heptagenid nymphs...... 5 Larvae of Chironominae . 28 11 Unidentified insect...... 5 Pupae of Chironomidae . 14 4 Gastropod (Lymnaea stagnalis)...... 38 Larvae of Tipulidae? . 15 G Adult terrestrial fly . 3 The young chub were not found where small trout or yraulus parvus . 4 most other small fish occur, hence they do not come directly into competition with other stream fish. For the larger specimens, six stomachs are not sufficient for a generalization, 5. Eucalia inconstans (Kirtland). Frequent in the lower but the principal items listed are not found in trout stomac~. section, below station 5. Specimens of the stickleback The absence of crayfish is surprising. In any cas:, \ e were most easily obtained in late summer and fall. scarcity of the species makes it an unimportant factor in t e It was often seen lurking in the shelter of logs, lily life of the stream as enemy, competitor, or food of the trout. pads, Potamogeton, or Chara. Several individuals 4. Rhinichthys atronasus (Mitchill). Occasional or perhapS appear in the stomachs of the speckled trout. . . ot seen frequent III the beaver-meadow section. n 1 5 The food of specimens collected June 17 to below. The examples collected ranged from . September 4, 1930, is presented in table 9.