Chapter 5: Choosing the Appropriate Management Tools

Grassland management involves manipulating the vegetation through disturbance to achieve predetermined goals. The tools of disturbance are varied so you will need to pick those most appropriate to achieve the particular objectives you have set for conservation of your grassland.

This chapter describes the primary tools of disturbance, the context in which you can apply them, and what overall effect you can expect depending on which is used and how it is applied.

Rest - When and How Much

Grasslands were shaped by fire, drought, and grazing by mammals and insects; however, there were seasonal periods of rest when plants had a chance to recover from the effects of defoliation, top kill, and interrupted growth.

A key principle of grassland management is ensuring a proper balance of rest and disturbance. Vegetation can be manipulated by varying the rate, intensity and frequency of disturbance in relation to rest periods. All organisms, including humans, are alike in that they cannot sustain a constant demand on their energy. Without sufficient, timely rest to replenish energy reserves, their ability to survive and reproduce diminishes.

Click here for a more detailed description of this image.

Typical stored energy cycle for a cool-season prairie grass. Any disturbance which severely reduces new leaf growth will prevent the plant from storing energy and it will eventually die. This knowledge will enable you to protect desirable plants and use disturbance to eliminate undesirables.

Long-term protection from disturbance may be unhealthy. For some types of grassland, elimination of defoliation (grazing) or fire will initiate plant successional trends that over the long-term are characterized by loss of species diversity and lower growth potential. Depending on the climatic zone, these grassland types will be replaced by shrub and tree cover. Therefore, knowing where and when to implement rest is a key management challenge.

A fenced enclosure in Fescue grassland. Protection from grazing for 20 years allowed Aspen invasion and the build-up of dead plant material that may include forbs. Central portions of some of the Fescue-basal crowns are dead, suggesting possible fungal infection. Photo: G. Trottier, Canadian Wildlife Service

Researchers do not have all the answers on how to manage rest, be it short-term for individual plants, or long-term to improve grassland condition. What they have determined is that although controls over degree and timing of disturbance are necessary to restore plant and/or grassland health, there is a point at which the absence of disturbance causes a build-up of organic matter on the ground surface, choking out plants and cooling the soil. This deprives soil micro-organisms of organic matter required for nutrient cycling. Plant productivity declines and species diversity may be affected. Wildlife species dependent on open grassland will be displaced.

Remember that some defoliation of grassland plants is desirable and will, in fact, stimulate greater growth, just as pruning our garden plants and shrubs improves their health.