INTRODUCTION
Controlling the attractiveness of the airport to birds and other wildlife is fundamental to good bird control. Indeed, it is probably more important than bird dispersal in terms of controlling the overall risk. If an airport produces easily accessible resources to birds/wildlife in terms of food, water, shelter and/or breeding sites, then they will continue to try and return despite any dispersal tactics in use to dissuade them. The control program is thus doomed to failure, unless the airport is made as unattractive to bird/wildlife as possible. This is where Grass Management comes in.
DEFINITION
Grass Management is the manipulation of natural vegetation in order to achieve some pre-determined goal. The natural vegetation is reclaimed from its natural state which was the birds/wildlife habitat, to be used for airport operations.
Grass Management has to do with reducing the grass level to a level stipulated by regulatory authorities like ICAO, for safe flight operations. Grass Management is an example of Habitat Modification – an approach to wildlife hazard control. Birds, just like all other animals, need water, food and shelter (habitat) in other to survive. The strategy of Habitat Modification entails modifying the environment to make it less attractive to birds in terms of these needs. Any action that reduces, eliminates or excludes one or more of these elements will result in a proportional reduction in the wildlife (birds) population at the airport.
All wildlife requires cover for resting, roosting, escape, territorialism and reproduction. Management of airside ground cover is peculiar to the available bird/wildlife species. Thinning the canopy of trees or selective removal of trees to increase their spacing must be continual at the airport in order to eliminate bird roosting point around the airport.
ICAO recommended grass height is 6-10 inches, though the grass height is usually tailored to suit the vegetation cover of the location of the airport.
METHODS OF GRASS MANAGEMENT
- Thinning
This is a term in grass management used for removal of some trees from a stand to give others more room (and resources) to grow. Thinning helps to optimize nature’s process and meet specific management objectives. Individual trees are removed before a stand becomes overcrowded, allowing the remaining trees to maintain higher growth rates.
- Clearing
This is the reduction of grass height, usually to suit the vegetation cover of the location. This can be obtained through manual cutting, with the use of cutlass and matchet; motorized cutting, with the use of machines like String Trimmers, Lawn Trimmers, Tractors, etc.; and use of herbicide. Some grasses can be effectively controlled in established lawns with common preemergence herbicides such as benefin, bensulide, dithiopyr, oryzalin, pendimethalin, and prodiamine.
- Clippings
These are grasses that fall off after clearing. If not packed, they may be carried by the blast of an aircraft into the engines, causing damage to the aircraft. Also, birds may pick up these clippings for nesting which may likely have adverse impact(s) at the airside. Accumulated clippings can also serve as habit to mammals, triggering a food chain/web in the process. Ultimately, clippings serve as soil enhancers, encouraging rapid grass growth.
CONCLUSION
Dense stands of trees and undergrowth on airport property can provide excellent cover for deer, coyotes raptor, rodents and other wildlife. Generally, these habitats should be cleared or at least sufficiently thinned to eliminate the desired cover and to allow easy visual and physical access by airport wildlife and hazard control personnel.
REFERENCE
- Oregan State University Extension Service.
- Dehinbo, J., Imoh E. and Ugwuegbulem D.(2007).
- Manual Bird/Wildlife Hazard Management – Federal Airports Authority of Nigeria (FAAN)
