160
7
for the flexibility discourse (Hiernaux 1993; Hiernaux et al. 2009, 2016; Mougins
et al. 2009; Dardel et al. 2014; Benjaminsen and Hiernaux 2019). Hiernaux’s data
material represents an unusually long and detailed data series in African ecological
drylands research.
The northern Sahel is an area with especially high resilience. Due to the domination of annual grass species in the Sahel and their strong seasonal dynamics, the
risk of overgrazing is limited to a short period in time. This critical period is in the
growing season before the seeds fall to the ground and can be as short as 2 weeks.
In fact, the two basic properties of Sahelian pastoral ecosystems, instability and
resilience, support the continued practice of transhumance in the southern Sahel
and of nomadism in the northern Sahel. Both these methods of utilizing resources
are based on mobility and maximal dispersion of livestock during the growing
season. For example, Tuareg nomads in Northern Mali move their camps approximately every third day in the rainy season. This is because they seek em-n-amsud
(the tip of the grass), which is said to be preferred by the cattle (Benjaminsen 1997).
► Example
A commonly shared idea about the impact of grazing in African drylands has been
that high grazing pressure around wells leads to overgrazing. To test this hypothesis,
Hanan et al. (1991) analysed biomass production around boreholes in the Ferlo region
in Senegal. During 30–35 years, the areas around these wells had been exposed to heavy
grazing. If this kind of pressure on the vegetation leads to degraded pastures, it should
be detectable in this area. Biomass production up to 25 km from 20 wells in the region
was studied by ground data measurements and the analysis of meteorological satellite
images at the end of the rainy seasons in 1987 and 1988. The conclusion was that there
was no consistent relationship between biomass production and distance to the wells,
and therefore no evidence of long-term degradation. In other words, the grass cover near
the wells grew just as fast as the grass further away. However, Hanan et al. (1991) did not
study changes in species composition as a result of grazing pressure. Evidently, grazing
may favour some species at the expense of others.
Definition
Theoretically, one may distinguish between two types of carrying capacity in an
equilibrium system—ecological and economic (Behnke and Scoones 1993). This
also leads to a theoretical divide between two types of overgrazing. Ecological
overgrazing is defined as a threshold, which the grazing intensity should not
exceed to avoid negative effects on the regeneration of pastures, while overgrazing
in economic sense implies that the pastures cannot satisfy the nutritional need of
the livestock. This need is again dependent on the production objective—whether
it is meat production for a market or milk production for own consumption
(Homewood and Rodgers 1987; Benjaminsen 1997) or whether the aim is
maximization of carcass weight or herd productivity per area unit (Benjaminsen
et al. 2006; Marin et al. 2020).
Chapter 7 · Pastoralists and the State
7
for the flexibility discourse (Hiernaux 1993; Hiernaux et al. 2009, 2016; Mougins
et al. 2009; Dardel et al. 2014; Benjaminsen and Hiernaux 2019). Hiernaux’s data
material represents an unusually long and detailed data series in African ecological
drylands research.
The northern Sahel is an area with especially high resilience. Due to the domination of annual grass species in the Sahel and their strong seasonal dynamics, the
risk of overgrazing is limited to a short period in time. This critical period is in the
growing season before the seeds fall to the ground and can be as short as 2 weeks.
In fact, the two basic properties of Sahelian pastoral ecosystems, instability and
resilience, support the continued practice of transhumance in the southern Sahel
and of nomadism in the northern Sahel. Both these methods of utilizing resources
are based on mobility and maximal dispersion of livestock during the growing
season. For example, Tuareg nomads in Northern Mali move their camps approximately every third day in the rainy season. This is because they seek em-n-amsud
(the tip of the grass), which is said to be preferred by the cattle (Benjaminsen 1997).
► Example
A commonly shared idea about the impact of grazing in African drylands has been
that high grazing pressure around wells leads to overgrazing. To test this hypothesis,
Hanan et al. (1991) analysed biomass production around boreholes in the Ferlo region
in Senegal. During 30–35 years, the areas around these wells had been exposed to heavy
grazing. If this kind of pressure on the vegetation leads to degraded pastures, it should
be detectable in this area. Biomass production up to 25 km from 20 wells in the region
was studied by ground data measurements and the analysis of meteorological satellite
images at the end of the rainy seasons in 1987 and 1988. The conclusion was that there
was no consistent relationship between biomass production and distance to the wells,
and therefore no evidence of long-term degradation. In other words, the grass cover near
the wells grew just as fast as the grass further away. However, Hanan et al. (1991) did not
study changes in species composition as a result of grazing pressure. Evidently, grazing
may favour some species at the expense of others.
Definition
Theoretically, one may distinguish between two types of carrying capacity in an
equilibrium system—ecological and economic (Behnke and Scoones 1993). This
also leads to a theoretical divide between two types of overgrazing. Ecological
overgrazing is defined as a threshold, which the grazing intensity should not
exceed to avoid negative effects on the regeneration of pastures, while overgrazing
in economic sense implies that the pastures cannot satisfy the nutritional need of
the livestock. This need is again dependent on the production objective—whether
it is meat production for a market or milk production for own consumption
(Homewood and Rodgers 1987; Benjaminsen 1997) or whether the aim is
maximization of carcass weight or herd productivity per area unit (Benjaminsen
et al. 2006; Marin et al. 2020).
Chapter 7 · Pastoralists and the State