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, Grant's 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% 6 0.3 to 7.7% 6 1.6 (mean 6 SE). During this period, cattle took a lower percent of bites on forbs in MWC (4.3% 6 1.7; P ¼ 0.01) and WC (5.9% 6 2.2; P ¼ 0.03) than in C (12.9% 6 0.9). These patterns were generally driven by Commelina spp., which comprised 65% 6 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 (r 2 ¼ 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. Resumen Los impactos de los herbívoros silvestres sobre selecció n de la dieta del ganado fueron investigados en un pastizal del este de Á frica de Agosto del 2001 a Febrero del 2002. En el estudio se compararon las dietas del ganado en potreros accesibles exclusivamente al ganado (C) y en potreros accesibles a megaherbívoros (elefantes y jirafas), herbívoros silvestres mayores de 15 kg (zebras, ñ us, gacelas, oryx, alce africano y bú falos) y ganado (MWC) y en potreros accesibles a no-mega herbívoros silvestres y ganado (WC). En ninguna de las épocas de muestro hubo diferencia entre tratamientos en la selecció n para la mayoría de especies de zacates (P. 0.05). Sin embargo, en Febrero, cuando las condiciones fueron relativamente secas, la selecció n de hierbas difirió entre tratamientos y el porcentaje de mordidas efectuadas por el ganado en esta clase de forraje aumentó (P , 0.005) de 1.8% 6 0.3 a 7.7% 6 1.6. Durante este periodo, el ganado registró porcentajes de mordidas de hierbas má s bajos en los potreros MWC (4.3% 6 1.7; P ¼ 0.01) y WC (5.9% 6 2.2; P ¼ 0.03) que en los accesibles solo al ganado (12.9% 6 0.9). estos patrones generalmente estuvieron regidos por las plantas del género Commelina spp., las cuales comprendieron 65% 6 9.4 del total de las mordidas de hierbas. Estas diferencias estuvieron notablemente asociadas con diferencias en la cobertura de hierbas, la que fue positivamente correlacionada con el porcentaje de mordidas (r 2 ¼ 0.86, P , 0.01). Debido a que las hierbas pueden ser un compo...

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

“…Cattle reduced herbivore use for each of the four most common, medium-sized wild herbivore species: plains zebra, Grant's gazelle, eland, and oryx ( Figure 3). Although cattle are primarily grazing herbivores, their diet at our study site can be as much as 15% forbs (non-grass herbs) (Odadi et al 2007), and this is reflected in their ability to competitively suppress not only grazing wildlife, but also mixed feeders. None of these reductions is likely due to direct interactions with cattle or herders; cattle herds are present in the designated plots for only 12-16 h per year.…”

“…In a series of experiments, we assessed the effects of wild herbivores on cattle foraging behavior, nutrition, and performance (weight gain) during dry and wet seasons (Odadi et al 2007(Odadi et al , 2009(Odadi et al , 2011. We also measured vegetation cover (the forage available to the cattle) during these trials.…”

Ecological Importance of Large Herbivores in the Ewaso Ecosystem

“…Grazing wildlife such as zebra may sometimes compete with cattle for food (Odadi et al, 2007). As described above, the KLEE plots independently manipulate the presence of cattle, megaherbivores, and all other wildlife.…”

Clarifying competition: the case of wildlife and pastoral livestock in East Africa

“…Existing research on competition between wildlife and livestock generally has treated it as interspecific sympatric competition, where individuals of different species vie for the same resource in an ecosystem (Prins 2000). Arguments for or against such competition have relied on dietary overlap (Fritz et al 1996;Mishra et al 2004;Odadi et al 2007;Vila et al 2009) as evidence for competition. This approach can be as simple as depicting grazers competing with grazers and browsers with browsers.…”

“…Where attempts have been made to move beyond diet/habitat overlap, researchers have relied on experimental designs where wildlife and livestock are enclosed in fenced pastures. For example, the effects of wildlife and livestock on vegetation are often conducted through timed runs within experimental blocks measuring a few hectares (Odadi et al 2007;Young et al 1998). While such work provides insights on the mechanisms behind competition, they provide little information about the nature of wildlife-livestock interactions in less-controlled, real-world situations where pastoral livestock and wildlife are highly mobile and the variability of external factors are strongly felt.…”