Grazing lawns contribute to the subsistence of mesoherbivores on dystrophic savannas

Verweij, Richard J. T.; Verrelst, Jochem; Loth, P.; Heitkönig, Ignas M. A.; Brunsting, A.M.H.

doi:10.1111/j.2006.0030-1299.14209.x

Cited by 99 publications

(116 citation statements)

References 28 publications

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“…However, the evidence for facilitation in ungulate communities due to increased resource access through removal of obstructing grass parts during the dormant season is weak (Arsenault & Owen-Smith 2002). Although grazing facilitation in Bénoué N. P. is an important mechanism in ungulate communities during the wet season (Verweij et al 2006), we found no indication of grazing facilitation on unburned sites during the dry season when grasses are dormant. Instead, it is more likely that the aggregated co-occurrence patterns on unburned sites resulted from the use of patches of tall and dense grass by several species as escape cover to avoid predation (Moe et al 1990).…”

Section: Co-occurrence Patternscontrasting

confidence: 58%

Savanna fires govern community structure of ungulates in Bénoué National Park, Cameroon

Klop

Goethem

2008

J. Trop. Ecol.

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Abstract:We studied the effects of savanna fires on the structure of local ungulate communities in a West African woodland savanna. The distribution of 11 ungulate species over 9−15 burned sites (the number of which increased as burning activity continued during the dry season) and 7−13 unburned sites was compared with a variety of null models or randomized 'virtual communities'. Five different parameters of community structure were examined: body mass distribution, co-occurrence patterns, species richness, species density and guild dominance. Overall, ungulate species were not randomly distributed over burned and unburned sites. The regular spacing of body masses in the set of species recorded on burned and unburned sites indicated competition, since species similar in body mass are more likely to compete than species of different size. However, co-occurrence patterns on burned sites were random, indicating absence of competition at fine spatial scales due to differential habitat use within the burned landscape. Although the attractiveness of the regrowth on burned sites resulted in higher numbers of ungulates compared with unburned sites, species richness was not different. Grazers were the dominant guild on burned sites, but there were no differences in species richness or species density between grazers and browsers on unburned sites.

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Section: Co-occurrence Patternscontrasting

confidence: 58%

Savanna fires govern community structure of ungulates in Bénoué National Park, Cameroon

Klop

Goethem

2008

J. Trop. Ecol.

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“…We postulate that the effects of shifting mosaics of grazing lawns maintained by hippos improve the quality of available forage close to water, which attracts herbivores in the MMNR riparian-edge habitats (McNaughton 1983;OwenSmith 1988;Fryxell 1991;Eltringham 1999;Adler et al 2001;Olff et al 2002;Arsenault and Owen-Smith 2002;Verweij et al 2006;Van Wieren and Bakker 2008). In contrast, the intense and homogeneous livestock grazing in the pastoral ranches limits forage intake by herbivores (Arsenault and Owen-Smith 2002;Verweij et al 2006), and repels herbivores from water points. Ultimately, continued sedentarization of pastoralists in the Mara region will progressively exclude herbivores and other wildlife from the pastoral areas of the Mara, similar to patterns reported for other parts of Masailand (Western et al 2009;Msoffe et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Hippopotamus and livestock grazing: influences on riparian vegetation and facilitation of other herbivores in the Mara Region of Kenya

et al. 2011

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Riparian savanna habitats grazed by hippopotamus or livestock experience seasonal ecological stresses through the depletion of herbaceous vegetation, and are often points of contacts and conflicts between herbivores, humans and their livestock. We investigated how hippopotamus and livestock grazing influence vegetation structure and cover and facilitate other wild herbivores in the Mara region of Kenya. We used 5 km-long transects, each with 13 plots measuring 10 9 10 m 2 , and which radiate from rivers in the Masai Mara National Reserve and adjoining community pastoral ranches. For each plot, we measured the height and visually estimated the percent cover of grasses, forbs, shrubs and bare ground, herbivore abundance and species richness. Our results showed that grass height was shortest closest to rivers in both landscapes, increased with increasing distance from rivers in the reserve, but was uniformly short in the pastoral ranches. Shifting mosaics of short grass lawns interspersed with patches of medium to tall grasses occurred within 2.5 km of the rivers in the reserve in areas grazed habitually by hippos. Hence, hippo grazing enhanced the structural heterogeneity of vegetation but livestock grazing had a homogenizing effect in the pastoral ranches. The distribution of biomass and the species richness of other ungulates with distance from rivers followed a quadratic pattern in the reserve, suggesting that hippopotamus grazing attracted more herbivores to the vegetation patches at intermediate distances from rivers in the reserve. However, the distribution of biomass and the species richness of other ungulates followed a linear pattern in the pastoral ranches, implying that herbivores avoided areas grazed heavily by livestock in the pastoral ranches, especially near rivers.

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“…In diverse herbivore communities, the existence and strength of facilitation can determine the net effect of cattle and wildlife on one another and hence are important to long-term cattle-wildlife coexistence. Facilitation of forage quality or accessibility is usually defined as a short-term effect that bulk-feeding herbivores can have on forage for smaller herbivores (Bell, 1971;Gordon, 1988;Verweij et al, 2006). Facilitation through habitat modification involves long-term effects of different herbivore species on soil nutrient distribution and plant community composition (Arsenault and Owen-Smith, 2002).…”

Section: Introductionmentioning

confidence: 99%

Pathways for Positive Cattle–Wildlife Interactions in Semiarid Rangelands

Augustine¹,

Veblen²,

Goheen³

et al. 2011

Smithsonian Contributions to Zoology

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ABSTRACT. Livestock-wildlife interactions in rangelands are often viewed in terms of competition, but livestock and native ungulates can also benefit each other through longterm modifications of rangeland habitats. Here we synthesize research on rangelands in central Laikipia focusing on two types of cattle-wildlife interactions that have implications for their long-term coexistence. The first interaction occurs via redistribution of soil nutrients within the ecosystem, which is a consequence of the use of bomas (temporary corrals) to manage livestock. Our studies on two different soil types show that rotational boma management creates hectare-scale patches in the landscape that are enriched in soil and plant nutrients and persist for decades to centuries. In both of the predominant soil types in Laikipia, forage phosphorus content is low relative to ungulate demands during peak lactation. Nutrient-rich boma sites (hereafter referred to as glades) provide a key wet-season forage resource of nutritional sufficiency for lactation. Our studies further show that a wide range of native ungulates selectively use glades relative to surrounding nutrient-poor habitats. Impala (Aepyceros melampus) in particular show intensive use of glades on sandy soils and are rare in portions of the landscape lacking glades. A second important pathway for cattle-wildlife interaction occurs through the influence of native browsing ungulates on woody vegetation. Shrub and tree cover has been increasing in Laikipia over the past century, followed by increases in native browsers in recent decades on ranches where wildlife are allowed to coexist with cattle. Our exclosure experiments in central Laikipia indicate that native browsers suppress shrub encroachment on both dominant soil types. However, the strength of browser effects are three to seven times greater on sandy soils, where two browsers, dik-dik and elephants, are both abundant, compared to heavy clay soils, where elephants are the only dominant browser. In the clay soils, native browsers still exert a significant influence on dynamics of the dominant tree, Acacia drepanolobium, and suppress encroachment by subdominant shrub species. Browser effects on woody vegetation likely enhance forage production for cattle and maintain open habitats favored by native grazers for predator avoidance. Taken together, our studies indicate that boma rotation and browser control of shrub encroachment are key interaction pathways that promote cattle-wildlife coexistence in the Ewaso ecosystem.

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Grazing lawns contribute to the subsistence of mesoherbivores on dystrophic savannas

Cited by 99 publications

References 28 publications

Savanna fires govern community structure of ungulates in Bénoué National Park, Cameroon

Savanna fires govern community structure of ungulates in Bénoué National Park, Cameroon

Hippopotamus and livestock grazing: influences on riparian vegetation and facilitation of other herbivores in the Mara Region of Kenya

Pathways for Positive Cattle–Wildlife Interactions in Semiarid Rangelands

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