Fire‐induced negative nutritional outcomes for cattle when sharing habitat with native ungulates in an African savanna

Abstract

Summary Prescribed burning is used in tropical savannas to improve habitat conditions for domestic and wild herbivores, but its effects on the ecological interactions between these herbivore guilds have never been assessed experimentally. Understanding such effects will contribute towards more informed management of both guilds in landscapes where they share habitats. We investigated the effects of burning on the nutritional outcomes for cattle sharing habitat with wildlife in a Kenyan savanna ecosystem. We compared forage availability and cattle forage and nutrient intake rates across burned and unburned areas cattle accessed exclusively, and those they shared with medium‐sized wild ungulates, both with and without megaherbivores (elephants and giraffes). We performed these measurements in May 2013 (wet period, 2 months post‐burning) and February 2014 (dry period, 11 months post‐burning). Additionally, we monitored wildlife use of these areas. Prescribed burning enhanced cattle nutrition, but only in areas cattle did not share with wildlife. Shared foraging with wildlife reduced cattle forage and nutrient intake rates by 37–97% in burned areas (burns), but not in unburned areas; these reductions corresponded with reduced herbage availability in the shared burns. In May (the wet period), cattle met their nutrient intake requirements in burns, regardless of whether they were sharing these areas with wildlife. However, in February (the dry period), nutrient requirements were unmet or tended to be unmet in burns shared with wildlife; requirements were met or significantly exceeded in the unshared burns. Experimental exclusion of megaherbivores did not moderate these effects, suggesting that they were primarily caused by medium‐sized wild ungulates which were highly attracted to burns. Synthesis and applications. Prescribed burning produces negative nutritional outcomes for cattle when sharing habitat with wild ungulates. Because these effects could negatively influence livestock–wildlife coexistence, burning should be applied prudently in such human‐occupied savanna landscapes. Specifically, because unburned areas serve as refuge foraging areas during the dry season, interspersing burns with unburned areas could minimize fire‐driven negative interactions between cattle and wild ungulates. Conversely, burning could be used to draw wildlife away from valuable cattle foraging areas, such as those near available water.

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

“…As opposed to vegetation growing off termite mounds, vegetation on mounds maintains high levels of essential nutrients even during the dry season (Grant & Scholes, ; Naiman et al., ). Therefore, large herbivores are likely to rely more heavily on termite mounds and similar nutrient‐rich hotspots (e.g., glades and burned areas) during dry periods, as has also been reported in our study ecosystem (Odadi et al., ; Veblen, ) and elsewhere (Davies, Levick, et al., ; Davies, van Rensburg, et al., ). Increased nutritional importance of mounds to herbivores during the dry season could magnify the negative effects of shared foraging with wild herbivores on selection of termite mounds by cattle.…”

“…By contrast, reduced selection of termite mounds could be detrimental to cattle during the dry season when both forage quality and quantity decline. Parallel to these postulated season‐dependent effects, shared foraging with wild herbivores in burned areas, which like termite mounds are also nutrient‐rich hotspots, was nutritionally detrimental to cattle during dry season but not during wet season (Odadi et al., ). Burned areas help cattle meet their nutritional (crude protein and digestible dry matter intake) requirements for maintenance and growth, but intense competition for these nutrient hotspots with wild herbivores during the dry season impairs the ability of cattle to meet these requirements (Odadi et al., ).…”

“…Parallel to these postulated season‐dependent effects, shared foraging with wild herbivores in burned areas, which like termite mounds are also nutrient‐rich hotspots, was nutritionally detrimental to cattle during dry season but not during wet season (Odadi et al., ). Burned areas help cattle meet their nutritional (crude protein and digestible dry matter intake) requirements for maintenance and growth, but intense competition for these nutrient hotspots with wild herbivores during the dry season impairs the ability of cattle to meet these requirements (Odadi et al., ). While we did not assess the actual nutritional implications of the effects of reduced termite mound selection on cattle, we suspect that they could be generally similar to those for burned areas.…”

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

“…The presence of wild LMH reduces cattle performance, at least during dry periods, see also, Ref. . Competition between cattle and wild LMH appears to be intensified in burned areas and on termite mounds, both of which are nutrient‐rich foraging hotspots that attract high concentrations of LMH .…”

Human impacts in African savannas are mediated by plant functional traits

“…Changes in the local population sizes of animals, such as elephants, may have profound effects on savanna structure (Asner et al ., , ; but see Kalwij et al ., ) and may prevent woody encroachment in low‐rainfall regions (Stevens et al ., ). Conservation management has the potential to strongly influence the populations of these megaherbivores (Fynn et al ., ), although wild animals may compete for (Odadi et al ., ), or partition (Charles et al ., ), resources with domestic cattle, sheep and goats.…”