Busch, David E.

McIntire, C. David

Oregon State University. Water Resources Research Institute

Weyerhaeuser Company

Undetermined

ScholarsArchive@OSU

FINAL REPORT TO WATER RESOURCE SRESEARCH INSTITUT EOREGON STATE UNIVERSITYTITLE : Plant Production in Experimental Streams : A Cooperative Researc hProject with Weyerhaeuser CompanyGRANT PERIOD : July 1, 1975 - June 30, 1976FUNDING DURINGGRANT PERIOD : WRRI - $7,67 5Weyerhaeuser Co . - $7,500FP.w1 ;a ; _REPORT PREPARED BY :	David E . BuschResearch Assistant, BotanyC . David McIntir eProfessor of Botany1 ~C Y•~'r[■h. ‘w)ztIMF-N16INTRODUCTIONDuring the winter of 1974, representatives of the Research Departmen tof Weyerhaeuser Company contacted C . David McIntire, Department of Botanyand Plant Pathology, for the purpose of establishing a cooperative researc hprogram at the Company ' s experimental stream facility, about eight mile snorthwest of the town of Cougar, Washington . This facility was constructe dby Weyerhaeuser Company on the St . Helen ' s Tree Farm in 1964 . The genera lobjectives of research conducted at this experimental station are : (1) toprovide a contribution to the fundamental knowledge of stream processes ;(2) to investigate ways in which productivity can be managed in fresh-wate rstreams to enhance their value to man ; and (3) to study the effects of theCompany ' s forest management strategy on water resources . Research in th eexperimental streams has been underway since 1965, and the initial wor kemphasized life history studies of aquatic insects and fish .Investigators in the Research Department of the Company at Longview ,Washington, have recognized the importance of beginning experiments t ohelp understand patterns of energy flow in lotic (stream) systems as suchpatterns relate to the activities of man . Of particular interest to th eCompany is the effect of nutrient enrichment on the bioenergetics of strea morganisms . The experimental streams are autotrophic systems, the dynamic sof which are essentially controlled by the rate of primary production andthe properties of the algal assemblages that grow in these systems . It wasa need for professional assistance in the areas of primary productivity an dalgal taxonomy and ecology that prompted the proposal by the Company for acooperative research project with the Department of Botany and Plan tPathology at Oregon State University .2The initial funding period for this project was supported by th eWeyerhaeuser Company and covered the period from September 1, 1974 t oAugust 31, 1975 . In the early part of 1975, it became apparent thatadditional funding for some equipment items, supplies, and computer time woul dcontribute to the success of the project and enhance the cooperative arrange -ment with the Weyerhaeuser Company . At that time a proposal was submitted t othe Water Resources Research Institute, Oregon State University, for a modes tsum to help us supplement the very limited resources available for thi sproject . We are sincerely grateful to the Institute for their suppor tduring the period from July 1, 1975 through June 30, 1976 . It is quit eprobable that the additional funds from Oregon State University provide dthe stimulus for two additional years of funding from the Weyerhaeuse rCompany (through summer of 1977), and that a project originally funded a t$7,500 has, in fact, been expanded into a program with total suppor tslightly over $31,000 .3DESCRIPTION OF EXPERIMENTAL STREAM FACILIT YThe Experimental Stream Facility is located on the Weyerhaeuse rSt . Helen's Tree Farm in the Cascades, about eight miles northwest o fthe town of Couger, Washington . The elevation is about 1,200 feet, an dthe snow cover can vary from a few inches to almost four feet durin gthe period from December through March . The study area includes abou tfive acres and is adjacent to the Kalama River . The site is surrounde dby a nine-foot fence, and the terrain slopes gently towards the river .The soil is of volcanic origin with large pyroclastic rocks overlyingfinely-divided pumice . There is a single building on the site wit hliving quarters and a small laboratory area .A large natural spring provides the water for the experimental streams .The water flows over a weir into a distributing pond and from there to eac hof three stream beds . The volume of water which flows into each streamvaries from about 0 .5 c .f .s . in the fall to 0 .8 c .f .s . during the winter .The streams are four feet wide and range in length from 400 to 700 feet .The streams consist of a series of riffles and pools, and the stream bed sare filled with small stones (0 .75 to 1 .5 inches) covered by larger rubble .Water velocity in the streams varies from about 1 to 1 .75 feet per second ,depending on the gradient .RESTATEMENT OF OBJECTIVE SThe general objective of this research project is to determine th eeffects of nutrient enrichment and other environmental changes on rates o fprimary production and on the structure of algal communities in experimenta lstreams . Nutrient enrichment--primarily nitrogen-will simulate introductions4related to forest management policies practiced by Weyerhaeuser Company ,namely forest fertilization and nutrient introductions resulting fro mlogging activities . Effects of shading on plant production also will bemonitored and related to the Company's management policies . Results ofwork with the aquatic plants will be integrated with results of concurren tstudies of insect and fish production by scientists at the Compan y ' slaboratory at Longview . Final interpretation of the combined set of datawill be synthesized into a view of the bioenergetics of lotic ecosystem sas influenced by various management strategies .Specific Objectives :The specific objectives of this project are :1. to determine effects of nutrient enrichment on the structure of plan tcommunities in experimental streams ;2. to determine effects of nutrient enrichment on the primary productivit yand energy budget of experimental streams ;3. to determine the effects of shading on plant production and energ yflow in experimental streams ;4. to relate the structure and primary production of algal assemblage sto animal production and the trophic ecology of experimental streams ;5. to interpret the results of the experimental work within the contextof management policies and interests of the Weyerhaeuser Company ;6. to interpret the results of the experimental work within a theoretica lcontext of lotic ecosystem dynamics .5PROGRESS THROUGH SPRING 197 6Scientific BackgroundThe dominant energy source for woodland streams is allochthonou sorganic matter (Petersen and Cummins, 1974), and this energy input i ndetrital form from the watershed is usually much greater than the autochthoriou sinput by aquatic plants . Man ' s activities on the watershed vegetation tend sto change the dynamics of lotic ecosystems . For example, logging increase sthe light energy and inorganic nutrients available to lotic plants (Borman net . al ., 1974), and these increases stimulate the production of aquati cplants (autotrophy) in streams . Therefore, managers of woodland stream sare faced with such questions as :(1) What will be the magnitude of th evegetational response? (2) What form will an increase in stream autotrophybe manifested -- algal biomass, insect biomass, or export? (3) How efficientlywill greater energy input by stream vegetation be transferred to a product o finterest (e .g ., fish biomass) ?An experimental approach utilizing laboratory streams is sometimes usefulfor the examination of hypotheses relating to the bioenergetics and structur eof lotic ecosystems . However, such studies are often conducted at theexpense of reality (Warren and Davis, 1971), and the value of the results i ssometimes difficult to determine relative to biological processes in natura lstreams . While the investigation of plant and animal dynamics after pertur -bation is confined by the recirculating nature of most laboratory streams ,the Weyerhaeuser corporation's experimental streams offer a flow-throug hdesign that permits a more realistic interpretation of experimental results .6Recovery from perturbation is of critical importance in understandin gstream systems . The low constancy of environment typical of natural streamsprevents the establishment and persistence of climax communities in th emanner of terrestrial systems . The extent that communities can advanc efrom immature to more mature stages will differ among and within streams .Also, changes in community composition will affect the biomass and pro -duction of vegetation and consumer organisms, as well as environmenta lmodification by the biological components of the system . The system' sresilience and resistance to perturbation are inevitably tied to communit ycomposition and its changes through time . The results presented belowcontribute to the understanding of stream system responses to perturbatio nrelative to light intensity and nutrient enrichment .Experimental Procedure sThe project was designed as a sequence of two experiments, designate dthe winter and summer experiments . The winter experiment involved reducin glight intensity, while the summer experiment was concerned with nutrien t(nitrate) enrichment at different light intensities .The winter experiment was run from December, 1975, through May, 1976 .The upper riffle of the three streams was shaded (85%), while the lowe rriffle received full sunlight . Six sets of data were obtained during thi speriod . The summer experiment was started in July, 1976, and will runthrough October, 1976, while collecting eight sets of data . The lighttreatments were retained for the summer experiment, but the ambient nitrat econcentration was increased from 25 to 100 ppb in two streams - at th einitiation of the experiment in one and after high herbivore standing crops7developed in the other . Before both experiments most of the plant (algal )and animal biomass was removed by physically agitating the gtbhe substrate swith a rake . This agitation simulated a freshet of water scouring biomas soff substrates in a natural stream .The collection of each set of data involved measurements of periphyto nand invertebrate components in a riffle ; fish were not stocked in the streamduring these experiments . Periphyton measurements included ash-free dr yweight, pigment concentration, export, taxonomic composition of algae, andprimary production according to the methods of McIntir e /(1968) . Measurement sof invertebrates included taxonomic composition of standing crop and expor twith estimations of herbivore and carnivore biomass, according to the method sof Bisson et . al . (1975) . Periphyton samples were collected and analyzed byO .S .U . personnel, and invertebrate samples were collected and analyzed b yWeyerhaeuser personnel .Results and Discussion of the Winter Experimen tThe recovery of the stream system after the catastrophic reduction o fbiomass in the riffles was characterized by a rapid accumulation of alga eand invertebrates . Figures I-III present measures of total biomass (ashfree dry weight), algal standing crop (chlorophyll a concentration), an danimal standing crop (dry weight estimated from observed body size) .These patterns of accumulation do not indicate a steady, continual increas ein living material with distinct differences between streams receivin gdifferent intensities of light . Total biomass (Figure I) exhibited an increase ,decrease, and subsequent increase after the perturbation for both the shade dand unshaded streams . This pattern was also observed in the estimates ofalgal density in the riffles (Figure II) . However, the unshaded riffle sshowed a faster accumulation of algae than the shaded riffles during th efirst 70 days . Standing crop of invertebrates (Figure III) differed fro mthis pattern . Invertebrate biomass increased and then gradually decrease din both streams during the experiment .The patterns of algal, invertebrate, and total biomass represente dbiological responses to an increase of resources . The removal o fbiomass increased a critical resource (space) for periphytic algae unde rconstant physico-chemical conditions . The subsequent accumulation o falgae increased the food resource for the invertebrates . Grazing reducedalgal density, and reduced algal density supported a lower invertebrat estanding crop . Estimates of herbivore and carnivore biomass (Figure III )indicated herbivore response to algal increase followed by carnivore respons eto herbivore increase .At this point, the analysis of data is restricted by a backlog o fsamples . OWRT ' s involvement in this project was instrumental in th einitiation of sampling . The scope of the project and the Weyerhaeuser-O .S .U .involvement extend to August, 1977 . While interpretation of the experiment sis conjecture, the preliminary results of the winter experiment tend t osupport the following generalizations :1) The initial algal response is a function of physical factors (i .e . ,light and nutrient availability) . The initial difference in algal biomas saccumulation according to light intensity (the winter experiment) an daccording to nitrate concentration (unpublished O .S .U .-Weyerhaeuser research )support this contention .92) Predation by invertebrates has a severe impact on the accumulatio nof algae biomass, obscuring differences in standing crop relative to ligh ttreatments . This ability of invertebrates to rapidly consume an alga lgrowth is similar to the observations of Dickman (1973) .3) Community composition changes are continual through the tim eframe of the experiment . Figure IV shows that the ratio of chlorophyll cto chlorophyll a decreased with time . In this case, chlorophyll c indicate sthe abundance of diatoms relative to the filamentous green algae, bot hgroups of which are the primary constitutents of the periphyton assemblage sin the experimental streams . Changes in the pigment ratio during th eexperiments indicated an initial dominance by diatoms followed by agradual shift in dominance to filamentous chlorophytes, principall ythrough the growth of Zygnema . Figure IV also indicates a larger concen-tration of carotenoids relative to chlorophyll a in the unshaded riffles .This larger concentration is consistent with the protective role of carotenoid sfor chlorophyll a molecules at high light intensities .4) Invertebrate biomass may be a better estimate of autotrophy tha nalgal biomass . The relatively low chlorophyll a : herbivore ratios (Figur eV) with the high absolute abundances of herbivores (Figure III) in th eunshaded riffles suggested that algal biomass is a conservative quality i nlotic ecosystems and that increases in light and nutrient resources ar emanifested in herbivore biomass .5) Export of algal material is an important mechanism for stability i nautotrophic systems . Figure VI indicated that export is not a linear functio nof standing crop . Increased export at higher algal densities suggested that10less autrophic production was assimilated by grazers . Oscillations i nherbivore biomass will be of lower amplitude than algal biomass oscillationswith export as a dampening mechanism . Furthermore, export appeared to hav ea diurnal pattern similar to the observations of Mueller-Haeckel (1973) .CONCLUSIONSConsiderable research effort at the Weyerhaeuser Corporation and a tO .S .U . has been directed toward the interpretation of biological phenomen anecessary for the effective management of public and private stream resources .Biological processes in stream ecosystems are relatively difficult t ounderstand . Experimental results from this project to date emphasize someproblems . Periphyton biomass, an easily measured quantity, appears to b ea conservative quality of streams, of little diagnostic value of both auto -trophy or environmental conditions . Pigment, invertebrate biomass, an dexport analyses are informative with distinct trends in the context of th eexperiment and the experimental streams . However, these patterns are likelyto be modified by the spatial heterogeneity common in natural streams .The critical measurements necessary for adequate interpretation of loti csystem behavior-community composition analysis and production - are time-consuming ,expensive, and constrained by the limitations and artifacts of the equipmen tused . To interpret stream phenomena, conceptualization of the components ,processes, and functions in lotic systems must supersede problems of samplin gand spatial heterogeneity .11LITERATURE CITE DBisson, P . A., R . B . Herrman, and R. N. Thut . 1975 . Trout production i nfertilizer nitrogen enriched experimental streams . WeyerhaeuserCorporation Interim Report . Longview, Washington .Bormann, F . H., G. E . Likens, T . G . Siccama, R. S . Pierce, and J . S . Eaton.1974 . The export of nutrients and recovery of stable conditionsfollowing deforestation at Hubbard Brook . Ecol . Mono . 44 :255-277 .Dickman, M. 1973 . Changes in periphytic algae following bicarbonateadditions to small streams . J . Fish. Res . Bd . Can . 30 :1882-1884 .McIntire, C . D . 1968. Structural characteristics of benthic alga lcommunities in laboratory streams . Ecology 49 :520-537 .Mueller-Haeckel, A. 1973 . Different patterns of synchronization in diurna land nocturnal drifting algae in the subarctic summer . Aquilo . Ser .Zool . 14 :19-22 .Petersen, R . C ., and K . W . Cummins . 1974 . Leaf processing in a woodlan dstream . Freshwat . Biol . 4 :343-368 .Warren, C . F ., and G . F . Davis . 1971 . Laboratory stream research :objectives, possibilities, and constraints . Ann . Rev . Ecol . Syst .2 :111-144 .S	IZ- • 4	.q c	6 © 0a . .shaded riffles 50	100	150®unshaded riffle: TIME days00ZZ~NVI 1Eo-unshaded riffles-shaded riffles50	100TIME days480 :665 El Id 11 ISI iI"CFIGURE Vshaded riffles	50o-unshaded riffles TIME100days‘!.z lueB °Iu) 6.w :oq .5 -ND 6welan ONIONVIS :1110dX3 W01V .

Plant production in experimental streams : a cooperative research project with Weyerhaeuser Company

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Plant production in experimental streams : a cooperative research project with Weyerhaeuser Company

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