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Nafus, A., Mcclaran, M. P., Archer, S. R. & Throop, H. L. (2009) Multi-species allometric models predict grass biomass in semi-Desert rangeland. Rangeland Ecology & Management
 

Summary: Nafus, A., Mcclaran, M. P., Archer, S. R. & Throop, H. L. (2009) Multi-species allometric
models predict grass biomass in semi-Desert rangeland. Rangeland Ecology & Management
(In Press)
Abstract
Multi-species allometric models to predict grass biomass may increase field study
efficiency by eliminating the need for species-specific data. We used field measurements over
two growing seasons to develop single- and multi-species regression models predicting current
years' aboveground biomass for 8 common cespitose grass species. Simple and step-wise
regression analyses were based on natural log expressions of biomass, basal diameter, and
height; and a dummy variable expression of grazing history. Basal diameter had the strongest
relationship with biomass among single- (adj. R2
= 0.800.91) and multi-species (adj. R2
= 0.85)
models. Regression slopes (b) for diameter among single- (b = 1.011.49) and the multi-species
(b = 1.25) models suggesting that biomass will double when diameter increases ~75%. Height
and grazing history added little predictive value when diameter was already in the model. When
applied to actual populations, biomass estimates from multi-species models were within 329%
of estimates from the single-species models. Although the multi-species biomass-size
elationship was robust across the cespitose life-form, users should be cautious about applying
ur equations to different locations, plant sizes and population size-structures.

  

Source: Archer, Steven R. - Savanna/Woodland Ecology Lab., School of Natural Resources and the Environment, University of Arizona

 

Collections: Environmental Sciences and Ecology