Leaf Pack Ecology 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

Leaf Pack Background  ID macroinvertebrates  Determine health of stream  Rate of leaf decomposition  Food preferences of macroinvertebrates

Leaf Pack for High School?  Develop curriculum to meet state standards for high school students Hypotheses Tested  Total richness and abundance of macroinvertebrates will vary with leaf pack size  Leaf decomposition rates differ among levels of moisture, physical abrasion, and macroinvertebrate colonization

Methods: Leaf Pack Size  Dry, mixed leaf types were weighed then placed into onion bags  Both a tin foil label and paper label were used  5 g, 10 g, 20 g, 30 g in triplicate  All deployed in forest riffle

Harvesting: Leaf Pack Size After 4 weeks in the stream...  Place leaf pack in 250 micron sieve then in ziplock bag  Open leaf packs in sorting tray, then rinse off all bugs in a sieve, preserve bugs in 95% ethanol

Does Size Matter? 20 gram leaf pack had the largest number of macroinvertebrates 20 gram leaf pack had the most taxonomic groups

Does Size Matter? Leaf Pack Network Water Quality Scores were similar

Ridley High School Little Crum Creek Wetlands Pond Folsom, PA

RHS Leaf Packs White Clay Creek has far more macroinvertebrates than Ridley HS Little Crum Creek can be compared to the pond and the wetland as a more rich and abundant area

RHS Leaf Packs Abundance(#)

Methods: Leaf Decomposition  Dry maple or oak leaves were weighed (10 g) then placed into onion bags  Both a tin foil label and paper label were used  10 g/each, 5 bags of oak, 5 bags of maple per site (50 leaf packs total)  Dried O/N at 60°C  Deployed to 5 different sites at Stroud

Site 1: Meadow Riffle

Site 2: Flood Plain Wetland

Site 3: Forested Stream Edge

Site 4: Forested Riffle

Site 5: Forested Pool

Site 6: Control (greenhouse)

Methods: Leaf Decomposition Each week...  Gather 1 oak and 1 maple leaf pack from each site  Wash leaves of sediment and bugs, allow leaves to dry in greenhouse for 30 minutes  60°C oven O/N, then obtain dry mass  Burn leaves in kiln  Obtain mass of ash

Leaf Pack Dry Mass Remaining (%)

Leaf Pack Organic Material Remaining (%)  Dry Mass of Leaves – Ash = Organic Material Remaining  Sources of error: handling, humidity, less sensitive scale

Discussion  20 g of leaves in a leaf pack allows for more diversity and abundance  Locations with more water and turbidity help to break down leaves more rapidly Questions to investigate further: How do precipitation and temperature impact the decomposition of leaves?

Back to the Classroom  Created a reference sample to help students identify macroinvertebrates commonly found on school grounds  Created a lesson plan to have students use leaf pack in the spring  Students 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.

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 sorting  Sean Kelley for Leaf Pack in the classroom advice  NSF EAR Introducing Critical Zone Observatory Science to students and teachers