Definitions. Background. Diversity in Urban Grasslands Effects Ecosystem Functioning. NYSTA Nov. 13, 2013 Research Update

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1 Diversity in Urban Grasslands Effects Ecosystem Functioning NYSTA Nov. 13, 2013 Research Update Grant Thompson MS/PhD Dr. Jenny Kao-Kniffin Definitions Ecosystem Function properties of an ecosystem directly or indirectly of human benefit; maintaining nutrient or hydrologic cycles, regulating services, provisioning services, and of cultural or recreational value 1,2 Urban Grasslands ecosystems dominated by turf-forming species created and maintained by humans for aesthetic and recreational (not grazing) purposes (i.e. lawns) 3 1 Hooper, D., et al. (2005). "Effects of biodiversity on ecosystem functioning: a consensus of current knowledge." Ecological monographs 75(1): Mellenium Ecosystem Assessment. (2005). Ecosystems and human well-being, Island Press Washington, DC. 3 Groffman, P. M., et al. (2009). "Nitrate leaching and nitrous oxide flux in urban forests and grasslands." Journal of environmental quality 38(5): Background Biodiversity Ecosystem Function (BEF) research as undergone great debate in the last few decades and was initially proposed by Darwin In a range of ecosystems including native grasslands (prairies), terrestrial and marine aquatic systems biodiversity has been shown to increase many ecosystem functions including productivity, stability, resistance to invasion, and nutrient assimilation. Mechanisms for BEF findings are still debated; niche partitioning, facilitation/complementarity, portfolio effect

2 Experimental Design Random incomplete factorial design Six monocultures, three 3-way mixes, three 6-way mixes, and one 12-way mix; five replicates each 12 turfgrass components were selected as a species pool and randomly assigned to diversity level treatments Turfgrass selections were based on commonly used and commercially available selections Grown in greenhouse conditions for 7-months in soil/sand media (2:1 mix v/v). Mesocosm Components Botanical Name Common Name 'Bullseye' Festuca arundinacea Bullseye Tall fescue 'Falcon V' Festuca arundinacea Falcon V Tall fescue * 'Spartin II' Festuca ovina var. duriuscula Spartin II Hard fescue ff 'Garnet' Festuca rubra Garnet Creeping Red fescue ff * 'Zodiac' Festuca rubra var. commutata Zodiac Chewings fescue ff 'Intrigue 2' Festuca rubra var. commutata Intrigue Chewings fescue ff 'Amazing GS' Lolium perenne Amazing Perennial ryegrass * 'Fiesta 4' Lolium perenne Fiesta 4 Perennial ryegrass 'Two Putt' Poa annua var. reptans Two Putt Annual bluegrass 'Bedazzled' Poa pratensis Bedazzled Kentucky bluegrass * 'Supranova' Poa supina Supranova Supine bluegrass * 'Microgreen' Trifolium repens Microgreen Micro-white clover l * * Monoculture ff Fine fescue group l Legume Hypotheses 1. Productivity On average, higher diversity assemblages will produce more biomass than the average of monocultures. 2. N-retention More diverse communities will retain more nitrate-nitrogen compared to monocultures 3. Belowground diversity Higher diversity assemblages will result in increased soil microbial diversity.

3 Clipping Collection 17 weekly clippings Lysimeters 2 leachate collections Canopy Coverage

4 Biomass & Soil Collection Results - Productivity Clipping Biomass by Diversity Level Summed 17 weekly clipping biomass (g-dry wt.) A B AB AB Mono. 3-Poly. 6-Poly. 12-Poly. Diversity Level P-value: * Results - Productivity Standing Biomass by Diversity Level Standing biomass (g-dry wt.) A B AB AB Mono. 3-Poly. 6-Poly. 12-Poly. P-value: * Diversity Level

5 Results [NO 3- ] Leachate NO3-N by Diversity Level Leachate NO3-N Concentration (mg NO3- N/L) A B B AB Mono. 3-Poly. 6-Poly. 12-Poly. Diversity Level P-value: * Soil Bacterial Diversity Axis Bacterial TRFs by Diversity Level Mono 3-Poly 6-Poly 12-Poly PCR-based molecular analysis of soil community TRF structure based on relative abundance of fragments Axix 1 Soil Bacterial Diversity Mean Bacterial TRFs by Diversity Level Axis Mono. 3-Poly. 6-Poly. 12-Poly Axis 1

6 Conclusion 1. Productivity in moderately diverse (3-component) assemblages, standing canopy and clipping biomasses are enhanced compared to monoculture treatments 2. N-Retention higher nitrogen retention in 3- and 6- compnent assemblages compared to monoculture. High variability at highest diversity level (12-) due to low statistical power (replication) 3. Soil bacterial diversity Significant differences between monocultures and polycultures. 4. Soil fungal diversity analysis is under way, results not yet clear. Questions A grant from the Towards Sustainability Foundation funded parts of this research. Contact: GLT43@CORNELL.EDU