Abstract

VECCHIO, María Cristina; GOLLUSCIO, Rodolfo A  and  CORDERO, Miriam I. Estimation of the carrying capacity at paddock scale in natural grasslands of the Flooding Pampa, Argentina. Ecol. austral [online]. 2008, vol.18, n.2, pp.213-222. ISSN 1667-782X.

We estimated the Carrying Capacity (CC) of a farm by combining satellite images, aimed at measuring the area of each plant community, with biomass measurements to estimate Aboveground Net Primary Production (ANPP) and the proportion of ANPP that can be consumed by animals (Harvest Index; HI). We estimated CC of each paddock as the mean CC of the different plant communities, weighed by the area occupied by each community within the paddock. Carrying Capacity of each community was obtained as the ratio between the product of ANPP x HI and the individual annual intake. We estimated the ANPP of the most conspicuous plant communities (B and I) within an area that had been fenced to exclude domestic herbivores two years before the beginning of this study. We estimated HI as the ratio between Consumption and ANPP, estimating animal intake from the biomass loss between entry and exit of animals from grazed paddocks. Community B showed a higher ANPP and HI than community I (4584 vs. 2969 kg DM.ha^-1.yr^-1 and 75% vs. 61%, respectively). The Carrying Capacity of each paddock ranged between 0.6 and 0.8 animal units.ha^-1.yr^-1, was associated to the proportion of the area occupied by community B, and was higher than the CC estimated from empirical models. Our results suggest that both quality and reliability of CC estimates depend on quality and reliability of available ANPP and HI data.

Keywords : Carrying capacity; Aboveground net primary production; Harvest index; Plant community map.

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