Seasonal space-time dynamics of cattle behavior and mobility among Maasai pastoralists in semi-arid Kenya

Abstract

This study was conducted to understand how seasonality in drylands influences the space–time dynamics of cattle behavior and mobility among pastoralist managed Zebu cattle. The study relies on the use of handmade collars holding global positioning system (GPS) units to document the spatially and temporally explicit patterns of cattle mobility, field based herd-follows to document cattle behavior, and key informant interviews to document the role of pastoral herding strategies in explaining these patterns. Data were analyzed as a function of seasonality, distance from household, time of day, and land cover zone. During the dry season, there was an unexpectedly high frequency of grazing/walking cattle behavior. This pattern is attributed to ‘tracking’ strategies of Maasai pastoralists resulting in movement to niche grazing areas. During the wet season a bimodal distribution of grazing behavior can be attributed to milking strategies. The study concludes that simple, low cost GPS collars are an effective and easily replicable method to help understand the spatial and temporal dynamics of cattle behavior and mobility, and patterns of cattle mobility are related to seasonal constraints. Differences between different cattle behaviors can be partly explained by cultural herding practices of Maasai pastoralists.

Introduction

Pastoralism is considered the most important and sustainable livelihood system in the world's arid and semi-arid lands (Sandford, 1983). More than half of the world's pastoralists are in Africa (Reid et al., 2008), and within parts of East Africa, where arid and semi-arid lands encompass up to 60% of the land area, pastoralism is the dominant livelihood system (Bourn and Blench, 1999). Pastoralists who reside within arid lands employ a range of adaptive strategies that facilitate mobility and avert risk in the face of spatial and temporal variability of environmental resources (Behnke et al., 1993, Scoones, 1994a, Niamir-Fuller, 1998). These strategies include, but are not limited to, the pooling of labor resources (Sieff, 1997, Turner, 1999), continuous tracking of resources (Niamir-Fuller, 1999), accessing key resource areas (Scoones, 1991, Ngugi and Conant, 2008), and the use of culturally designated grazing reserves (Ruttan and Mulder, 1999). Pastoral livestock micro-mobility, in particular, has been used to infer how pastoralists cope with environmental variability by documenting seasonal patterns of forage intake and energy expenditure (Coppock et al., 1986, Western and Finch, 1986).

Geographically oriented social scientific research on pastoral coping strategies has traditionally focused on understanding the social, political, economic and ecological processes of access to, and utilization of, resources in arid and semi-arid lands (Bassett and Zimmerer, 2003). This body of research typically suffers from inattention to the non-human agents that make these processes possible (that is, the type of livestock species itself) and a lack of understanding of the varied ethological aspects of livestock. Alternatively, natural science researchers have suggested that focusing on animal behavior allows for greater understanding of how forage maximization and energy expenditure minimization of cattle can be achieved (Vavra and Ganskopp, 1998). This may be done either by documenting the time dedicated to grazing activities, which can be used as a proxy for forage intake (Coppolillo, 2000, Schlecht et al., 2004), or by measuring the distance traveled by livestock from a pastoral household, which is an indicator of energy expenditure and how far away adequate forage and water resources are located (Western and Finch, 1986, Semenye, 1987, Coppolillo, 2000). However, this type of research is often devoid of a context-specific set of socio-ecological and cultural pastoral herding strategies.

Pastoralists are highly dependent on resource availability, which is driven by precipitation (Ellis and Galvin, 1994). Precipitation in East Africa is spatially and temporally heterogeneous, and is a function of the north–south movement of the Inter-Tropical Convergence Zone (ITCZ) (Norton-Griffiths et al., 1975). Inter-seasonal precipitation is one of the main factors influencing herding strategies, which are manifested through cattle mobility and behavior in various ways. During the wet season, precipitation increases soil moisture, stimulates dormant seeds, and enhances growth of perennial grasses (O'Connor and Everson, 1998). Herders are thought to respond to increased resource availability by keeping cattle as close to the household as possible, which reduces the energy expended by cattle, increases forage intake, and reduces the amount of labor required for herding (Coppolillo, 2000). Such a strategy would be illustrated by a higher frequency of grazing and a lower frequency of walking behaviors. During the dry season this trend is expected to reverse, as forage resources are likely to decrease in both quality and quantity. Consequently, herders direct cattle to forage available spaces further from the household and the frequency of walking behavior is theorized to be higher while grazing behavior is lower, resulting in higher energy expenditure and lower forage intake (De Boer and Prins, 1989, Samuels et al., 2007). At the same time, pastoralists are known to rely on a key socio-ecological strategy known as tracking. Niamir-Fuller and Turner (1999: 37) suggest that tracking occurs when, “… herders scout and track ecological variability, both spatially and temporally, by constant monitoring, and adjust(ing) the behavior of their animals.” This strategy ensures that pastoralists are able to access niche areas and take advantage of ecological heterogeneity on the landscape (Behnke et al., 1993, Niamir-Fuller, 1998). However, few empirical studies have sought to document the explicit spatial, temporal, and behavioral manifestations of tracking in traditional pastoral herding practices, and the extent to which these practices differ under seasonal constraints (Niamir-Fuller, 1999).

The purpose of this paper is therefore to address previous shortcomings of research on pastoral coping strategies by providing a more robust geographical and behavioral interpretation of pastoral livestock micro-mobility. This is done through a case study of Maasai pastoralists and their cattle in East Africa, and is executed by testing two hypotheses that postulate how relationships between cattle mobility and behavior vary seasonally.

• The total distance and duration of cattle mobility in the wet season is less than during the dry season.

• The frequency of grazing behavior is greater than walking behavior in the wet season.

• The frequency of walking behavior is greater than grazing behavior in the dry season.

These hypotheses are empirically evaluated by combining field based techniques documenting cattle behavior with explicit space–time tracking of cattle mobility, and supplemented by key informant interviews with herders for a pastoral area in southern Kenya.

These data allow for more accurate assessments on the degree to which inter-seasonal variability influences the grazing strategies of pastoralists. These data would also provide a unique opportunity to understand how pastoral livelihood systems and herding strategies are likely to be affected by: (1) climate change, given that current projections indicate that the climate in East Africa will witness greater variability both within and between seasons (Christensen et al., 2007, McSweeney et al., 2007); and, (2) pastoral sedentarization, given that trends indicate further individualization of tenure and reduced livestock mobility (Rutten, 1992, Fernandez-Gimenez and Le Febre, 2006).