Sevilleta LTER AboveGround Net Primary Production

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Sevilleta LTER Above-Ground Net Primary
Production Black Grama and Creosotebush Sites
1999 through 2002. Esteban Muldavin,
Doug Moore, Dave Lightfoot, and Karen Wetherill
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Acknowledgements Mike Friggens, Terri Koontz,
Heather Simpson, Chris Roberts, and Shana
Pennington.
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• Establish long-term net primary production (NPP)
  measurements on the Sevilleta in keeping with
  network standards and core datasets
• To support cross-site analysis, sampling
  procedures followed those established at the
  Jornada LTER
• (Huenneke, L.F., D. Clason, and E. Muldavin.
  2001. J. of Arid Environments 47257-270)
• Jornada protocols for NPP by John Anderson,
  Cathie Sandell and Nancy Stotz
• Double sampling
• Volumetric non-destructive plant measurements on
  permanent one-meter quadrats
• Biomass samples of similar volumes collected in
  adjacent areas for regressions of mass on volume.

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• Sampling established in 1999 at Five Points
  Grassland and Larrea rodent web sites, and at the
  Blue Grama Grassland Site in 2002.

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• Quadrat sampling design was overlain on rodent
  webs to aid direct correlations between producers
  and consumers.

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• Layout that minimizes site impacts and that is
  efficient

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• Annual regressions suffice for most species (50
  out 60)

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• Dominants require seasonal and possibly yearly
  regressions

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R20.81
R20.94
R20. 78
R20. 88
R20.97
R20.88
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Five Points Grassland Site Standing Biomass
Code Species Name Weight
Weight (g/m2) w/o winter BOER4 Bouteloua
eriopoda 44.3 50.5 ATCA2 Atriplex
canescens 5.41 4.94 GUSA2 Gutierrezia
sarothrae 4.77 4.70 SPCR Sporobolus
cryptandrus 3.15 4.66 SPCO4 Sporobolus
contractus 1.77 2.53 OPPHP Opuntia
phaeacantha 0.91 0.52 CRCR3 Cryptantha
crassisepala 0.67 0.95 HIJA Hilaria
jamesii 0.57 0.81 ERPU8 Erioneuron
pulchellum 0.42 0.61 SPFL2 Sporobolus
flexuosus 0.36 0.41 MUAR2 Muhlenbergia
arenicola 0.29 0.41 HOGL2 Hoffmannseggia
glauca 0.28 0.33 PLPA2 Plantago
patagonica 0.26 0.39 ARPUP6 Aristida purpurea
0.25 0.36 SPWR Sphaeralcea wrightii 0.24 0.33
PHIN Phacelia integrifolia 0.22 0.32 BOGR2 Boutel
oua gracilis 0.09 0.12
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Five Points Larrea Site Standing Biomass
Code Species Name Weight Weight

(g/m2) w/o winter LATR2 Larrea
tridentata 83.5 94.0 GUSA2 Gutierrezia
sarothrae 4.34 5.12 ERPU8 Erioneuron
pulchellum 1.46 2.12 LEFE Lesquerella
fendleri 0.96 1.05 HIJA Hilaria
jamesii 0.80 1.13 OPCL Opuntia
clavata 0.80 0.93 SPCO4 Sporobolus
contractus 0.73 1.03 OPMA8 Opuntia
spp. 0.73 1.00 THAC Thymophylla
acerosa 0.72 0.98 SCBR2 Scleropogon
brevifolia 0.64 0.94 BOER4 Bouteloua
eriopoda 0.45 0.60 MUPO2 Muhlenbergia
porteri 0.40 0.41
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Web NPP based on 1999 and 2000 Regressions

• Some variation among webs at the Five Points
  Grassland

16 quadrats per web or 80 per site
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• Five Points Grassland Larrea site was more
  variable

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NPP and Precipitation

• C4 black grama production typically peaks with
  the monsoon

• C3 creosotebush growth tends to reflect winter
  moisture

• Non-dominant production is similar among sites

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• Black grama and creosotebush both track winter
  precipitation.

• Black grama tracks the summer monsoon, but
  creosotebush does not.

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• Creosotebush may respond to late season moisture
  and below normal temperatures

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• Grassland NPP is higher than at the Larrea site

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Conclusions

• NPP quadrat sampling design is efficient and low
  impact
• Sufficiently accurate and precise to detect
  subtle long term trends
• Applicable to the ecotones and other study sites.

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