Erastus Ngaruka
Rangeland productivity is influenced by several factors such as rainfall, soil condition, fire, herbivory, and other ecological forces like plant competition amongst others. In addition, human activities cannot be ignored when it comes to rangeland utilisation.
The adverse influence of these factors can disturb the normal ecological processes, leading to rangeland degradation.
One of the recurrent factors that shape rangeland ecosystems is fire (commonly known as veld fires or wildfires), which can occur naturally or as man made. Many farmers have negative perceptions about veld fires due to their dangerous and destructive nature. However, natural veld fire events serve a very important ecological function.
For example, burning moribund materials to allow regrowth or tillering, stimulating seed germination by cracking seed coats, and largely maintain vegetation structures in terms of spacing and balance (e.g., controlling bush encroachment).
On the other hand, artificial fires are either started for a purpose (prescribed fire) or out of negligence. The prescribed fires are planned for rangeland management purposes to mimic natural influences. These types of fires can also become uncontrolled and devastating if poorly planned and managed.
Veld fires damage farm infrastructure (e.g., fences, pipes), the environment (habitats, soil, plants), and result in injuries and deaths in animals (livestock and wild animals), and humans as well. Further, fire burns the available forage materials, leaving animals with little or nothing to survive on.
Generally, natural veld fires are caused by lightning strikes, and mainly occur during the spring months or at the onset of the rainy season (September -November) when thunderstorms activities begin.
Therefore, farmers should already prepare to avoid huge losses. In some parts of Namibia, fire activities have already started, and most of these unplanned or accidental fires can be attributed to human activities including charcoal production, campfire, cigarettes, vehicles, hunting and poaching
activities, empty bottles or glass pieces that can magnify the sun’s heat and ignite dry grass.
The intensity of a veld fire is mainly influenced by the amount of fuel load such as dry grass or other moribund plant materials such as dead wood. The more the fuel loads, the higher the intensity of fire and impact, and on the other hand the wind influences the direction, speed, and spatial scale of the fire.
-Erastus Ngaruka is a technical advisor at Agribank’s Livestock & Rangeland division.