Chrissy Wilson 1 Tara Muenz 2 Dave Arscott 2 1 Ridley High School Folsom PA 2 Stroud Water Research Center Avondale PA Dried leaves become homes for macroinvertebrates Leaf packs replicate what happens in nature allow for the study of the stream ID: 448277
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Leaf Pack Ecology
Chrissy Wilson1, Tara Muenz2, Dave Arscott2 1Ridley High School, Folsom, PA2Stroud Water Research Center, Avondale, PASlide2
Dried leaves become homes for
macroinvertebratesLeaf packs replicate what happens in nature, allow for the study of the streamhttp://www.stroudcenter.org/lpn/Slide3
Leaf Pack Background
ID macroinvertebratesDetermine health of streamRate of leaf decompositionFood preferences of macroinvertebratesSlide4
Leaf Pack for High School?
Develop curriculum to meet state standards for high school studentsHypotheses TestedTotal richness and abundance of macroinvertebrates will vary with leaf pack sizeLeaf decomposition rates differ among levels of moisture, physical abrasion, and macroinvertebrate colonizationSlide5
Methods: Leaf Pack Size
Dry, mixed leaf types were weighed then placed into onion bagsBoth a tin foil label and paper label were used5 g, 10 g, 20 g, 30 g in triplicateAll deployed in forest riffleSlide6
Harvesting: Leaf Pack Size
After 4 weeks in the stream . . .Place leaf pack in 250 micron sieve then in ziplock bagOpen leaf packs in sorting tray, then rinse off all bugs in a sieve, preserve bugs in 95% ethanolSlide7
Does Size Matter?
20 gram leaf pack had the largest number of macroinvertebrates20 gram leaf pack had the most taxonomic groupsSlide8
Does Size Matter?
Leaf PackNetworkWater Quality Scores were similarSlide9
Ridley High School
Little Crum CreekWetlands
Pond
Folsom, PASlide10
RHS Leaf Packs
White Clay Creek has far more macroinvertebrates than Ridley HSLittle Crum Creek can be compared to the pond and the wetland as a more rich and abundant areaSlide11
RHS Leaf Packs
Abundance(#)Slide12
Methods: Leaf Decomposition
Dry maple or oak leaves were weighed (10 g) then placed into onion bagsBoth a tin foil label and paper label were used10 g/each, 5 bags of oak, 5 bags of maple per site (50 leaf packs total)Dried O/N at 60°CDeployed to 5 different sites at StroudSlide13
Site 1: Meadow RiffleSlide14
Site 2: Flood Plain WetlandSlide15
Site 3: Forested Stream EdgeSlide16
Site 4: Forested RiffleSlide17
Site 5: Forested PoolSlide18
Site 6: Control (greenhouse)Slide19
Methods: Leaf Decomposition
Each week . . .Gather 1 oak and 1 maple leaf pack from each siteWash leaves of sediment and bugs, allow leaves to dry in greenhouse for 30 minutes60°C oven O/N, then obtain dry massBurn leaves in kilnObtain mass of ashSlide20
Leaf Pack Dry Mass Remaining (%)Slide21
Leaf Pack Organic Material Remaining (%)
Dry Mass of Leaves – Ash = Organic Material RemainingSources of error: handling, humidity, less sensitive scaleSlide22
Discussion
20 g of leaves in a leaf pack allows for more diversity and abundanceLocations with more water and turbidity help to break down leaves more rapidlyQuestions to investigate further:How do precipitation and temperature impact the decomposition of leaves?Slide23
Back to the Classroom
Created a reference sample to help students identify macroinvertebrates commonly found on school groundsCreated a lesson plan to have students use leaf pack in the springStudents will create their own leaf pack experiment – looking at variables like location, leaf type, and size of leaf pack – then carry out their experiment and analyze their data.Slide24
Acknowledgements
Thank you to Dr. Dave Arscott and Tara Muenz for all of your help with the research and data analysis!Thank you to Tara Muenz and Dr. Anthony Aufdenkampe for the RET experience. Caitlin and Steffani (Downingtown STEM Academy) for sortingSean Kelley for Leaf Pack in the classroom adviceNSF EAR 1263212 Introducing Critical Zone Observatory Science to students and teachers