Towards sustainable livestock production systems: Analyzing ecological constraints to grazing intensity

Tamara Fetzel of the Institute of Social Ecology, Austria, assessed grazing intensity worldwide and examined whether it can be sustainably increased to meet future food demands.

Tamara Fetzel

Tamara Fetzel

Introduction

Increasing food production from cropland and grassland is essential to meet the future food demand of a growing world population without further land-use expansion. Food production is estimated to increase strongly to meet future food demands. On pasture lands, this would require a growth rate 40% larger than the production increase between 1962 and 2005 to close the food gap. Grasslands cover a large part of the global land-surface and hence it is of outstanding importance to increasing food production in a sustainable way, e.g. by not degrading essential ecosystem services. This project aims at contributing to a better understanding of the major determinants and ecological constraint of the global livestock production system and the analysis of further production potentials.

Methods

We assess grazing intensity (e.g. the share of Net Primary Production consumed by grazing animals) at the global scale in a spatially explicit manner. To do this, we use a number of global datasets on animal feed-demand, monthly availability of NPP and socio-economic frame conditions to analyze seasonal shortage and surplus periods of biomass supply and provide an estimate of how much additional biomass would be available if management were optimal (e.g. storage facilities were available).

Results

Seasonality of biomass provision creates in many parts of the world shortage and surplus periods of NPP which can be seen as ecological constraints to grazing intensity. In cold climates, grazing intensity is limited by a short growing period and the fact that biomass supply is severely constrained in winter. The same is true for many arid areas where biomass growth is severely limited during dry periods. This period of short biomass supply reduces the annual average grazing intensity by constraining the number of animals that can be fed by the amount of biomass available over the year. At the same time, in periods with biomass surplus not the entire useable fraction can be eaten by the animals. The limitations posed by seasonal patterns can be overcome by management such as storage options. We find that largest potentials for storage of biomass is located in Sub-Saharan Africa and Latin America, followed by Central and Eastern Asia.

Reference

[1] Wint W, Robinson TP (2008) Gridded Livestock of the World. Food and Agriculture Organization of the United Nations, Rome, Italy.

Supervisors

Petr Havlik and Juraj Balkovic, Ecosystem Services and Management Program, IIASA

Note

Tamara Fetzel of the Institute of Social Ecology, Austria, is a citizen of Austria. She was funded by the IIASA Austrian National Member Organization and worked in the Ecosystem Services and Management Program during the YSSP.

Please note these Proceedings have received limited or no review from supervisors and IIASA program directors, and the views and results expressed therein do not necessarily represent IIASA, its National Member Organizations, or other organizations supporting the work.


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Last edited: 03 February 2016

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