DOI: 10.5061/dryad.kprr4xh3g
title: Data from: Environmental controls on African herbivore responses to landscapes of fear

description: Herbivores balance forage acquisition with the need to avoid predation,
 often leading to tradeoffs between forgoing resources to avoid areas of
 high predation risk, or tolerating increased risk in exchange for improved
 forage. The outcome of these decisions is likely to change with varying
 resource levels, with herbivores altering their response to predation risk
 across heterogeneous landscapes. Such contrasting responses will alter the
 strength of non-consumptive predation effects, but are poorly understood
 in multiple- predator/multiple-prey systems. We combined fine-scaled
 spatial information on two predator and 11 herbivore species with
 remotely-sensed measurements of forage quantity and vegetation structure
 to assess variation in herbivore response to predation risk with changing
 environmental context, herbivore body size, herbivore foraging strategy
 (browsers versus grazers), predator type (ambush versus coursing hunters)
 and group size across a South African savanna landscape. Medium-sized
 herbivore species were more likely to adjust their response to risk with a
 changing resource landscape: warthog, nyala and wildebeest tolerated
 increased long-term predator encounter risk in exchange for abundant
 (warthog and nyala) or preferred (wildebeest) forage, and nyala selected
 areas with higher visibility only in landscapes where food was abundant.
 Impala were more likely to be observed in areas of high visibility where
 wild dog risk was high. In addition, although buffalo did not avoid areas
 of high lion encounter risk, large buffalo groups were more frequently
 observed in open areas where lion encounter risk was high, whereas small
 groups did not alter their space use across varying levels of risk. Our
 findings suggest that risk effects are not uniform across landscapes for
 medium-sized herbivores and large buffalo groups, instead varying with
 environmental context and leading to a dynamic landscape of fear. However,
 responses among these and other prey species were variable and not
 consistent, highlighting the complexities inherent to
 multi-predator/multi-prey systems.
description: From 12 July to 18 September 2014, which is the late dry season
 in HiP, groups of two trained observers (one field ranger paired with a
 volunteer) walked 30 line transects ranging in length from 2 to 11 km, for
 a total of 232 km, and recorded the locations and group sizes of all
 herbivores encountered with the use of binoculars, a GPS unit, compass and
 Bushnell Yardage Pro 1000 range finder. The field ranger was largely
 responsible for the observations, while the volunteer recorded them into
 the database. This census is performed biennially in HiP and is highly
 standardized across years and between transects, making consistent
 observer bias highly unlikely. The bearing of, and distance to, each
 sighting (using herd centres when groups were encountered) were recorded
 to calculate the location of each observation relative to the transect
 line. In cases where animals moved after they had been sighted,
 observations were recorded where the animal (or herd) was first seen. If
 an animal (or herd) was not initially observed, but rather disturbed by
 the observers and then seen running off, it was not recorded. Effects of
 detectability and distance on group counts were accounted for using
 Distance software. Each transect was walked between five and thirteen
 times over the course of the survey, yielding a total survey distance of
 2715 km. To avoid potential detection bias across different habitat types
 and vegetation densities, the datasets only include the observations
 recorded within 100 m of the observer (number of observations per species:
 red duiker = 52, grey duiker = 105, impala = 266, nyala = 287, kudu = 41,
 giraffe = 59, warthog = 101, wildebeest = 37, zebra = 82, buffalo = 145
 and white rhinoceros = 326). Transects were evenly distributed throughout
 the park, apart from the access-limited, south-western wilderness area
 that excluded from the study due to no available lion spatial data,
 encompassing all main vegetation types and variability in rainfall and
 elevation. An equal number of random points, matching the maximum number
 of observations for any one herbivore species (i.e. 326), were generated
 within 100 m buffers around the surveyed transects to represent available
 habitat.
description: Please see the README file