Supported by:

The role of small mammals in grassland degradation in China: Future research
by Dr Tony Arthur¹, Dr Roger Pech² and Professor Shi Dazhao³

Over the past two years we have developed proposed research directions in collaboration with a number of researchers in China.  These include Professor Shi Dazhao’s group at the China Agricultural University, our collaborators on our project in Tibet (Jie Bu – Tibetan Academy of Agricultural and Animal Sciences, Lin Hui – Tibet Bureau of Agriculture and Animal Husbandry, and Professor Zhang Yanming – North West Plateau Institute of Biology), and the Chinese Institute of Zoology (Dr Zhang Zhibin and his group).  In this paper we will outline briefly these proposed research directions.

Inner Mongolia

In a workshop at the China Agricultural University with Shi Dazhao in Beijing four distinct vegetation types (or states) were identified for grasslands.  Type I is ungrazed, type II results from light to moderate grazing by livestock, type III is heavily grazed by livestock and is the preferred habitat for Brandt’s vole, and type IV is degraded grassland with a high biomass of unpalatable species.  Ideally the system would be managed to maintain it in type II, and hence we focused on understanding the transition between type II and type III.  However, it is unlikely a simple state-and-transition model would be appropriate for this system because of the strong influence of climatic factors.  Strong climatic drivers also are a feature of Australian and New Zealand systems (eg. Arthur 2005; Pech et al. 1999; Pech and Hood 1998; Robley 2004). We propose developing a mechanistic, interactive model of the system, to underpin management in these grasslands.  Some of the required information would already be available, but estimation of some parameters would require further field research.  The model would have the following general components:

• Relationship between climatic variables and pasture production
• The impact of livestock on the pasture
• The impact of Brandt’s vole on the pasture and soil
• The response of Brandt’s vole to pasture and other factors such as climate
• Number of livestock determined by different management scenarios

A model such as this would lead to a management system which deals in an integrated way with all the processes that can lead to degradation and is more responsive to the prevailing climatic conditions.  The research would benefit from the inclusion of pasture scientists, economists to explore the economic implications of the management approach, and social scientists to explore the adoption of a more interactive management system. 

Tibet

Sustainable management of the grassland system in Tibet is critical not only for the livelihoods of the people there, but because the area encompasses the headwaters of Asia’s major rivers.  It is essential that this system is managed to prevent major erosion into the catchments, because it is well known from other continents that extensive denudation results in not only floods but also long-term reduction in river flow.  Erosion is already evident in many areas on the plateau and we have identified some key questions through our current research, with input from Professor Tony Sinclair (University of British Columbia), who has extensive experience in grassland ecosystem research.  At the general level, research is required to (1) identify areas that are not already degraded, and determine ways to prevent them from becoming degraded, and (2) determine how to prevent further degradation in already degraded areas and (3) develop methods to rehabilitate these areas.  Based on observations of Canadian tundra, it could take 30-50 years for recovery in some areas. 

It is currently not clear in this system whether pikas are a cause of degradation, a sign of degradation resulting from overgrazing by livestock, or a combination of the two.  We propose developing a more detailed understanding of the capacity of this system to support livestock at a level where the system is not pushed to a degraded state.  This will require research on:

• The production of pasture throughout the year
• The offtake of pasture by livestock
• The offtake of pasture by pikas and their response to food availability
• The causes of erosion in the system and recovery from erosion

As with Inner Mongolia, the research would benefit from the integration of pasture scientists, economists to explore the economic implications of management, and social scientists to explore the changes to society in this system.  We have already established collaboration with a social scientist (Beimatsho – Tibet Academy of Social Sciences) who is interested in these issues.

Summary

The work we propose here has the potential to underpin sound and sustainable management of grasslands in China.  It is focused on developing a clear understanding of the ecological and physical features that drive these systems.  These need to be integrated with economic and social considerations to properly advance future management of the grasslands.

Acknowledgements

Most of the material for this paper was collected during projects funded by ACIAR and AusAID in Inner Mongolia and Tibet.

References

Arthur, T. (2005)  Modelling a New Zealand Semi-Arid Dryland Ecosystem..  Unpublished contract report for Landcare Research, NZ.

Pech, R. P., Hood G. M., Singleton, G. R., Salmon, E., Forrester, R. I., and Brown, P. R. (1999). Models for predicting plagues of house mice (Mus domesticus) in Australia. In 'Ecologically-based Rodent Management'. (G. R. Singleton, L. A. Hinds, H. Leirs, and Z. Zhang Eds.) pp. 81-112. (ACIAR Monograph 59)

Pech, R. P. and Hood, G. M. (1998). Foxes, rabbits, alternative prey and rabbit calicivirus disease – consequences of a new biological control agent for an outbreaking species in Australia. Journal of Applied Ecology 35, 434-453.

Robley, A. Reddiex B. Arthur T. Pech R. and Forsythe D. (2004) Interactions between feral cats, foxes, native carnivores, and rabbits in Australia.  Arthur Rylah Institute for Environmental Research, Department of Sustainability and Environment, Melbourne. http://www.deh.gov.au/biodiversity/invasive/publications/interaction/index.html

¹CSIRO Sustainable Ecosystems

²Manaaki Whenua – Landcare Research

³College of Agriculture and biotechnology, China Agriculture University