Plant-Environment Interactions of Arctic Vegetation and Implications for CO2 Flux
Plant func3onal groups may shi? in response to altered climate in northern la3tudes (Loranty & Goetz 2012). Plant-­‐environment interac3ons influence microclimate, including temperature and moisture, which can influence microbial communi3es Microclima3c varia3on between plant func3onal groups may result in different rates of respira3on and CO2 flux from these plants and associated microbes 70 9 Thaw Depth (cm) 8 7 6 5 4 3 2 1 Lichen 40 30 Alnus 40 70 35 % Carbon 80 50 40 30 0 0 Lichen Betula 3 30 2.5 25 2 20 -­‐0.2 -­‐0.3 -­‐0.4 Moss Alnus Betula Figure 4. NEE, R, and GPP data from isolated patch types. Posi3ve NEE represents a CO2 source, and nega3ve NEE represents a CO2 sink. Values represent an average from measurements taken at two different days using a Li-­‐Cor 820. 10 0.5 5 0 0 Lichen Betula Moss Alnus Betula 0.1 Lichen Moss Betula Lichen Moss Betula 1.2 1 0.8 0.6 0.4 0.2 0 •  There are differences in microenvironment between plant groups, especially between thaw depth and temperature •  Alder and moss have higher microbial diversity than lichen and betula, which may indicate that more carbon substrates are able to be used by these A reciprocal transplant of moss and lichen patches might clarify vegeta3on types. the rela3onship between plant, •  Shrubs appear to be a net CO2 microenvironment, and CO2 flux sink, while mosses and lichen are a net source or neutral •  Differences in CO2 fluxes between plant func3onal groups may be par3ally driven by varia3ons in microclimate and microbial communi3es •  Link between environment and CO2fluxes may become more clear with reciprocal transplant data taken over 3me •  Contribu3ons to CO2flux by different plant func3onal groups can be used to predict how vegeta3on shi?s in response to climate change can alter ecosystem carbon balance Moss Alnus Betula AWCD AWCD 0.2 Conclusions & Future Direc3ons Figure 1. Microenvironment variables by plant func3onal type. One-­‐way ANOVA tests performed for each variable found significant differences in means (p<.05). Field measurements were taken five 3mes over the course of one month, and soil moisture and nutrient data was obtained from soil samples collected early in the month. •  Compare microenvironment and soil characteris3cs between isolated patches of plant func3onal groups •  Compare microbial community composi3on and CO2 flux between plant func3onal groups •  Begin reciprocal transplant experiment by switching moss and lichen plots to analyze rela3ve direc3on of plant-­‐
environment rela3onship over a longer 3mescale 0.3 0 -­‐0.5 15 1 Alnus Betula 0.4 15 5 Moss Moss 0.5 20 10 1.5 Lichen -­‐0.1 25 10 Alnus 0 30 20 Moss 0.1 0.6 -­‐0.6 Lichen 45 60 0.2 10 Betula DOC TDN Moss 0.7 20 90 Lichen Objec3ves •  Isolated patch types of four func3onal groups •  Measured microenvironment variables •  Measured CO2 flux with Li-­‐
Cor 820 •  Biolog assays to compare microbial communi3es 50 0 Lichen Methods 60 0 %Soil Organic Ma;er • 
0.3 Results Temperature (°C) • 
Paul
2
Bunn
Olaf College, 2Western Washington University, 3Woods Hole Research Center
Introduc3on • 
Sue
3
Mann , Andy
R (umol CO2/m2) 1St.
3
Natali ,
GPP (umol CO2/m2) Heidi
2
Rodenhizer ,
NEE (umol CO2/m2) Ellen
1
Squires ,
Alnus Betula Lichen Moss Figure 2. Boxplot of average well color development (AWCD) of the bacterial Biolog EcoPlates at the end of inocula3on for four different vegeta3on types. Alnus Lichen Moss Figure 3. Boxplot of average well color development (AWCD) of fungal Biolog FFPlates at the end of the inocula3on for three different vegeta3on types. References & Acknowledgements • 
• 
Loranty, M.M., and S.J. Goetz. 2012 Shrub expansion and climate feedbacks in Arc3c tundra. Environmental Research Le2ers 7 011005 doi:10.1088/1748-­‐9326/7/1/011005 We would like to thank The Polaris Project (NSF Award 1044610), personnel at The Northeast Science Sta3on, Cherskiy, Russia, St. Olaf College CURI,and John Schade