Wilfred O. Odadi

Lessons on the relationship between livestock husbandry and biodiversity from the Kenya Long-term Exclosure Experiment (KLEE)

Although livestock and wildlife share most of their ranges worldwide, little controlled experimental research has been done on their interactions. Since 1995 we have been manipulating the presence of cattle and large wild ungulates in a Kenyan savanna rangeland in order to better understand the nature of competition and coexistence between these two guilds of herbivores and how they affect biodiversity. In a replicated experiment in which different combinations of cattle and wild herbivores are allowed access to large-scale plots, we have been monitoring the impacts of these herbivores on vegetation, on the wild herbivores, and cattle themselves, and on a variety of other taxa. We have also been conducting experimental research to examine other ways in which livestock management in eastern Africa might affect biodiversity. These include studies on the impacts of fire, livestock corrals, and changes in tree density. This research has revealed the following patterns. (1) Cattle suppress many species of wild herbivores, presumably through competition for their shared resources. The nature of this competition, however, is contingent on rainfall and the presence of other herbivores. (2) Wild herbivores both compete with and facilitate cattle, depending on rainfall. (3) The pastoral practice of housing livestock nightly in protective corral enclosures (“bomas”) over time produces long-lived nutrient hotspots preferred by both livestock and wild herbivores. (4) Fire, frequently used by pastoralists in the past, is valuable for improving grass quality, with benefits for many species of wild herbivores. (5) Pastoral practices that reduce woody cover, including burning and boma construction, create local habitat patches that are preferred by wild herbivores, apparently for their greater anti-predator visibility. (6) Despite competition between livestock and wild herbivores, coexistence between these two guilds can be managed, and there are several positive (facilitative) pathways between livestock husbandry and wild herbivores and other biodiversity.

Effects of Wildlife on Cattle Diets in Laikipia Rangeland, Kenya

Abstract The impacts of wild herbivores on cattle diet selection were investigated in an East African rangeland during August 2001 and February 2002. The study compared cattle diets in plots exclusively accessible to cattle (C) and those accessible to megaherbivores (elephants and giraffes), non-megaherbivore wild herbivores > 15 kg (zebras, hartebeests, Grants gazelles, oryx, elands, and buffaloes) and cattle (MWC); or non-megaherbivore wild herbivores and cattle (WC). There were no treatment differences in selection of most grass species in either sampling period (P > 0.05). However, selection of forbs differed among treatments during February when conditions were relatively dry and percent of bites taken by cattle on this forage class increased (P < 0.005) from 1.8% ± 0.3 to 7.7% ± 1.6 (mean ± SE). During this period, cattle took a lower percent of bites on forbs in MWC (4.3% ± 1.7; P = 0.01) and WC (5.9% ± 2.2; P = 0.03) than in C (12.9% ± 0.9). These patterns were generally driven by Commelina spp., which comprised 65% ± 9.4 of total bites on forbs. Notably, these differences were associated with differences in cover of forbs, which was positively correlated with percent of bites on forbs (r2 = 0.86, P < 0.01). Because forbs may be critical components of cattle diets in such rangelands during relatively dry periods, these dietary changes may indicate potential seasonal costs of wildlife to cattle production. Looking for ways to offset such costs may be worthwhile for livestock properties that accommodate wildlife.

Herd Size-Dependent Effects of Restricted Foraging Time Allowance on Cattle Behavior, Nutrition, and Performance

ABSTRACT We tested the influence of herd size on the effects of restricted foraging time on cattle (Bos indicus) foraging behavior, nutrition, and performance in a Kenyan savanna rangeland. Using a randomized block design, we compared weight gain, forage intake, diet selection, dietary crude protein (CP) and digestible organic matter (DOM), bite and step rates, distance travelled, and activity time budgets between steers allowed unlimited foraging time (DNG) in predator-free areas with those herded diurnally in predator-accessible areas in large (200 steers; LDG), medium (150 steers; MDG), or small (100 steers; SDG) herds and corralled at night. Daily weight gain was greater (P < 0.01) in DNG (0.61 kg) or SDG (0.56 kg) than in LDG (0.19 kg) or MDG (0.29 kg) but did not differ (P = 0.591 ) between DNG and SDG. Likewise, daily organic matter intake was greater (P < 0.05) in DNG (6.2 kg) or SDG (5.4 kg) than in LDG (3.7 kg) or MDG (3.7 kg) but did not differ (P = 0.288) between DNG and SDG. Grazing time was lower (P < 0.01) in DNG (42.2%) than in LDG (71.3%), MDG (72.2%), or SDG (69.5%), while the reverse was the case for ruminating and/or resting time (47.1%, 12.1%, 11.9%, and 10.3% in DNG, LDG, MDG, and SDG, respectively). Bite rate was lower in DNG (13.1 bites · min-1) than LDG (21.0 bites · min-1; P = 0.068), MDG (27.7 bites · min-1; P = 0.13) or SDG (26.2 bites · min-1; P = 0.007). However, diet selection, CP, DOM, step rate, and distance travelled did not differ among treatments. Our findings demonstrate subdued negative effects of restricted foraging time when cattle are herded diurnally in small-sized herds. Application of this strategy could reduce the need for eliminating wild carnivores to facilitate unrestricted foraging time for cattle.

Conservation lessons from large‐mammal manipulations in East African savannas: the KLEE, UHURU, and GLADE experiments

African savannas support an iconic fauna, but they are undergoing large‐scale population declines and extinctions of large (>5 kg) mammals. Long‐term, controlled, replicated experiments that explore the consequences of this defaunation (and its replacement with livestock) are rare. The Mpala Research Centre in Laikipia County, Kenya, hosts three such experiments, spanning two adjacent ecosystems and environmental gradients within them: the Kenya Long‐Term Exclosure Experiment (KLEE; since 1995), the Glade Legacies and Defaunation Experiment (GLADE; since 1999), and the Ungulate Herbivory Under Rainfall Uncertainty experiment (UHURU; since 2008). Common themes unifying these experiments are (1) evidence of profound effects of large mammalian herbivores on herbaceous and woody plant communities; (2) competition and compensation across herbivore guilds, including rodents; and (3) trophic cascades and other indirect effects. We synthesize findings from the past two decades to highlight generalities and idiosyncrasies among these experiments, and highlight six lessons that we believe are pertinent for conservation. The removal of large mammalian herbivores has dramatic effects on the ecology of these ecosystems; their ability to rebound from these changes (after possible refaunation) remains unexplored.

Analysis of the Spatial Relationship between Cattle and Wild Ungulates across Different Land-Use Systems in a Tropical Savanna Landscape

In many African savanna landscapes, domestic and wild herbivores cooccur across different land-use systems, but the role of land-use in shaping their spatial relationship is poorly understood. We evaluated the spatial relationship between cattle and wild herbivores categorized by body sizes and feeding habits across different land-use types, namely, private ranches (PR), transitional lands (TRL), and pastoral grazing areas (PGA), in Laikipia County, Kenya. Cattle and wild herbivores spatial distribution data were obtained from Kenya’s Department of Resources Survey and Remote Sensing (DRSRS). Spatial relationships between cattle and different wild herbivore guilds were analyzed using Ripley’s bivariate function. In PR, wild herbivore guilds showed significant attraction to cattle at short distances. In TRL, wild grazers, mixed feeders, megaherbivores, and medium-sized ungulates exhibited significant attraction to cattle. Additionally, repulsion was observed between cattle and browsers at short distances under this land-use system. In PGA, wild grazers, mixed feeders, and megaherbivores repelled strongly with cattle at short distances while browsers and medium-sized ungulates were significantly attracted to cattle. Cattle and wild herbivores were more randomly and independently distributed in PR than in TRL and PGA. These spatial relationships imply better coexistence between cattle and wild herbivores in PR than in TRL and PGA.

Tightly Bunched Herding Improves Cattle Performance in African Savanna Rangeland

ABSTRACT Rotational grazing management approaches are regarded as strategies for sustaining rangeland productivity and continue to be applied across many parts of the world. In Africa, livestock farmers implementing rotational grazing often switch from traditional loosely bunched herding (LBH), in which animals within a herd are allowed to spread out naturally when foraging, to tightly bunched herding (TBH) with limited herd spread to increase animal impact on the range. However, there is little scientific information on the actual direct (short-term) effects of this altered herding strategy on livestock productivity. We investigated the direct effects of TBH versus LBH on foraging behavior, nutrition, and performance (weight gain) of cattle in a semiarid savanna rangeland in central Kenya. We conducted the study across two habitat types: a heterogeneous red soil habitat and a relatively homogeneous black cotton soil habitat. Across both habitats, cattle traveled 9–15% less, foraged 10–29% more efficiently, and put on 14–39% more weight when managed with TBH as compared with LBH. These changes occurred despite the fact that stock densities were double to several times higher under TBH, and cattle under this herding regime foraged less selectively, consuming preferred plants less (especially in the black cotton soil habitat) and consuming diets with lower crude protein content (in the red soil habitat). Financial projection showed that the benefit of increased cattle performance under TBH could sufficiently outweigh increased cost of additional labor required to implement this herding strategy. These findings suggest that TBH, as practiced here, can be implemented without livestock production or financial losses. Further, the research demonstrated reduced grazing selectivity under TBH indicates that this herding strategy could potentially be used to reduce grazing pressure on preferred forage plants and maintain herbaceous species diversity without sacrificing cattle performance.

Relationships Between Cattle and Biodiversity in Multiuse Landscape Revealed by Kenya Long-Term Exclosure Experiment

ABSTRACT On rangelands worldwide, cattle interact with many forms of biodiversity, most obviously with vegetation and other large herbivores. Since 1995, we have been manipulating the presence of cattle, mesoherbivores, and megaherbivores (elephants and giraffes) in a series of eighteen 4-ha (10-acre) plots at the Kenya Long-term Exclosure Experiment. We recently (2013) crossed these treatments with small-scale controlled burns. These replicated experimental treatments simulate different land management practices. We seek to disentangle the complex relationships between livestock and biodiversity in a biome where worldwide, uneasy coexistence is the norm. Here, we synthesize more than 20 yr of data to address three central questions about the potentially unique role of cattle in savanna ecology: 1) To what extent do cattle and wild herbivores compete with or facilitate each other? 2) Are the effects of cattle on vegetation similar to those of wildlife, or do cattle have unique effects? 3) What effects do cattle and commercial cattle management have on other savanna organisms? We found that 1) Cattle compete at least as strongly with browsers as grazers, and wildlife compete with cattle, although these negative effects are mitigated by cryptic herbivores (rodents), rainfall, fire, and elephants. 2) Cattle effects on herbaceous vegetation (composition, productivity) are similar to those of the rich mixture of ungulates they replace, differing mainly due to the greater densities of cattle. In contrast, cattle, wild mesoherbivores, and megaherbivores have strongly guild-specific effects on woody vegetation. 3) Both cattle and wild ungulates regulate cascades to other consumers, notably termites, rodents, and disease vectors (ticks and fleas) and pathogens. Overall, cattle management, at moderate stocking densities, can be compatible with the maintenance of considerable native biodiversity, although reducing livestock to these densities in African rangelands is a major challenge.

Cattle select African savanna termite mound patches less when sharing habitat with wild herbivores

Abstract African savanna termite mounds function as nutrient‐rich foraging hotspots for different herbivore species, but little is known about their effects on the interaction between domestic and wild herbivores. Understanding such effects is important for better management of these herbivore guilds in landscapes where they share habitats. Working in a central Kenyan savanna ecosystem, we compared selection of termite mound patches by cattle between areas cattle accessed exclusively and areas they shared with wild herbivores. Termite mound selection index was significantly lower in the shared areas than in areas cattle accessed exclusively. Furthermore, cattle used termite mounds in proportion to their availability when they were the only herbivores present, but used them less than their availability when they shared foraging areas with wild herbivores. These patterns were associated with reduced herbage cover on termite mounds in the shared foraging areas, partly indicating that cattle and wild herbivores compete for termite mound forage. However, reduced selection of termite mound patches was also reinforced by higher leafiness of Brachiaria lachnantha (the principal cattle diet forage species) off termite mounds in shared than in unshared areas. Taken together, these findings suggest that during wet periods, cattle can overcome competition for termite mounds by taking advantage of wildlife‐mediated increased forage leafiness in the matrix surrounding termite mounds. However, this advantage is likely to dissipate during dry periods when forage conditions deteriorate across the landscape and the importance of termite mounds as nutrient hotspots increases for both cattle and wild herbivores. Therefore, we suggest that those managing for both livestock production and wildlife conservation in such savanna landscapes should adopt grazing strategies that could lessen competition for forage on termite mounds, such as strategically decreasing stock numbers during dry periods.