Managing Gerbils On Your Land: Part 1

A gerbil invasion, especially in a grassland or savannah, can lead to serious crop damage. Control begins with understanding the behaviour of this pest, and should always be environmentally sensitive.

Gerbils of the genera Gerbilliscus, Desmodillus and Tatera are mostly found in the drier areas of South Africa’s grassland, savannah, Karoo and fynbos biomes. They are small rodents with shortish tails and long hind legs. Their droppings are small, oblong and spiked, and can easily go unnoticed.

As burrowing animals, gerbils prefer clay soils due to the cracks that typically form in them during the dry season.

Gerbil populations sometimes grow dramatically, with figures of 40 000 animals per hectare being reported. They can cause extensive crop damage by burrowing in the land as well as consuming freshly planted and germinating seed, and the ripening crop.

To manage gerbils effectively, it is necessary to understand their population dynamics and why they invade croplands.

• Food supply

Newly planted crops and crop residue offer a year-round food supply. There is no way of getting around this.

• Continual monoculture cropping

Given the demand for grain, farmers tend to make maximum use of all their arable land for a single crop species. This creates a highly favourable habitat for gerbils.

• Climate change

There is strong evidence that South Africa’s summer season is shifting to later in the calendar. Later rain gives gerbils a better chance of survival.