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Moss lore

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Moss lore

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  1. Moss lore • Moss NPP is inversely proportional to vascular plant production • Moss NPP ≥ black spruce in boreal forest

  2. Hypotheses • Moss NPP and vascular NPP are inversely related • Moss NPP increases positively with vascular ANPP up to a critical value (e.g., canopy closure), and then decrease. Moss NPP (g m-2 yr-1) Moss NPP (g m-2 yr-1) Vascular ANPP (g m-2 yr-1)

  3. 200 150 Moss NPP (g m-2 yr-1) 100 BIOME Boreal 50 Tundra 0 Boreal Tundra BIOME The first step: published moss NPP values for tundra and boreal forest 20 0.4 Boreal AK and CN = 39 Tundra AK = 8 Total studies = 47 15 0.3 Count 10 Proportion per Bar 0.2 5 0.1 0 0.0 0 50 100 150 200 Moss NPP (g m-2 yr-1)

  4. Alaska: upland tundra and boreal forest 200 150 Moss NPP (g m-2 yr-1) 100 50 BIOME Boreal 0 Tundra 0 100 200 300 400 500 Vascular ANPP (g m-2 yr-1)

  5. Alaska: upland tundra and boreal forest 200 Tundra slope = 0.5 (R2=0.51) Boreal slope = 0.1 (R2=0.40) Slopes sig. diff. @ P = 0.02 150 Why? Moss NPP (g m-2 yr-1) 100 50 BIOME Boreal 0 Tundra 0 100 200 300 400 500 Vascular ANPP (g m-2 yr-1)

  6. Shaver and Chapin 1991 (boreal multiplier?) Ruess et al. 2007 (most precise?) Alaska: upland tundra and boreal forest 200 150 Moss NPP (g m-2 yr-1) 100 50 BIOME Boreal 0 Tundra 0 100 200 300 400 500 Vascular ANPP (g m-2 yr-1)

  7. Position U Upland Wetland W Canada: wetlands and uplands 200 W What about wetlands? W 150 W Moss NPP (g m-2 yr-1) 100 W U 50 U U 0 0 100 200 300 400 Understory ANPP (g m-2 yr-1)

  8. 80 70 60 50 Moss NPP (g m-2 yr-1) 40 30 20 10 0 100 200 300 400 Spruce ANPP (g m-2 yr-1) Alaska: moss vs. spruce No relationship, but spruce is generally > moss

  9. Conclusions • Positive relationship between moss and vascular NPP • More support for H2 than H1, but… • Small sample size; missing wetlands, other veg. types • Variation in methods of measuring moss NPP may make comparisons difficult • Future: find more data, explore methods for measuring moss NPP, use meta-analytical techniques