ABSTRACT
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253 The Observational Site of an Alpine Meadow Grazing Ecosystem for a
Modeling Approach and Its Natural Conditions. . . . . . . . . . . . . . . . . . . 254 Modeling of an Alpine Meadow Grazing Ecosystem . . . . . . . . . . . . . . . . . . 255
Computer Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261 Test of the Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261 Sensitivity Analysis of Rotational Grazing Scheme . . . . . . . . . . . . . 261
A Simulated Rotational Grazing Experiment Using the Alpine Meadow Grazing Ecosystem Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Maximum Potential Productivity of the Summer-Autumn Pasture under Grazing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Maximum Potential Productivity of the SAP under Grazing Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Under Constant Grazing Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 Under Variable Grazing Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
INTRODUCTION
The alpine meadow grazing ecosystem is a subsystem of the alpine meadow ecosystem in QingZang Plateau, China. Grazing ecosystem research
has been conducted using an alpine meadow ecosystem matter cycling energy flow biological complex modeling system approach since Shiyomi et al. (1983). The meadow or pasture forms an ecosystem in which matter cycles and energy flows through the constitutive components such as atmosphere, plants, and animals, day by day. The amount of energy and materials passing through or accumulating within these components is affected by factors in complicated relations with each other. A grazing system embraces an entire biological complex of weather, soil, plants, and animals, together with the management imposed upon it by the grazier in order to attain desired objectives, and it should be subject to evaluation by Shiyomi’s system approach (1983, 1986). Modeling offers a way of bridging the gap between grazing experiments and real grazing ecosystems, provided the model includes the decision-making processes as well as the biological interactions between the animals and the meadow. Efficient utilization of alpine meadow is one factor of importance. The potential for highly efficient meadow husbandry optimizing herd management can be evaluated by using modeling. From this point of view, we are seeking, in the study, a rotational grazing scheme and an optimal grazing pressure for the alpine meadow husbandry by modeling an alpine meadow grazing ecosystem.
