Andrew J. Loveridge

Behavioral adjustments of African herbivores to predation risk by lions: spatiotemporal variations influence habitat use.

Predators may influence their prey populations not only through direct lethal effects, but also through indirect behavioral changes. Here, we combined spatiotemporal fine-scale data from GPS radio collars on lions with habitat use information on 11 African herbivores in Hwange National Park (Zimbabwe) to test whether the risk of predation by lions influenced the distribution of herbivores in the landscape. Effects of long-term risk of predation (likelihood of lion presence calculated over four months) and short-term risk of predation (actual presence of lions in the vicinity in the preceding 24 hours) were contrasted. The long-term risk of predation by lions appeared to influence the distributions of all browsers across the landscape, but not of grazers. This result strongly suggests that browsers and grazers, which face different ecological constraints, are influenced at different spatial and temporal scales in the variation of the risk of predation by lions. The results also show that all herbivores tend to use more open habitats preferentially when lions are in their vicinity, probably an effective anti-predator behavior against such an ambush predator. Behaviorally induced effects of lions may therefore contribute significantly to structuring African herbivore communities, and hence possibly their effects on savanna ecosystems.

Does the risk of encountering lions influence African herbivore behaviour at waterholes

A central question in the study of predator–prey relationships is to what extent prey behaviour is determined by avoidance of predators. Here, we test whether the long-term risk of encountering lions and the presence of lions in the vicinity influence the behaviour of large African herbivores at waterholes through avoidance of high-risk areas, increases in group size, changes in temporal niche or changes in the time spent in waterhole areas. In Hwange National Park, Zimbabwe, we monitored waterholes to study the behaviour of nine herbivore species under different risks of encountering lions. We radio-collared 26 lions in the study area which provided the opportunity to monitor whether lions were present during observation sessions and to map longer-term seasonal landscapes of risk of encountering lions. Our results show that the preferred prey species for lions (buffalo, kudu and giraffe) avoided risky waterholes. Group size increased as encounter risk increased for only two species (wildebeest and zebra), but this effect was not strong. Interestingly, buffalo avoided the hours of the day which are dangerous when the long-term and short-term risks of encountering lions were high, and all species showed avoidance of waterhole use at night times when lions were in the vicinity. This illustrates well how prey can make temporal adjustments to avoid dangerous periods coinciding with predator hunting. Additionally, many herbivores spent more time accessing water to drink when the long- and short-term risks of encountering lions were high, and they showed longer potential drinking time when the long-term risk of encountering lions was high, suggesting higher levels of vigilance. This study illustrates the diversity of behavioural adjustments to the risk of encountering a predator and how prey respond differently to temporal variations in this risk.

Individual vigilance of African herbivores while drinking: the role of immediate predation risk and context

Perceived risk of predation is considered to influence individual prey vigilance, but little is known about the extent to which the context (e.g. distance to cover, group size) and the immediate presence of predators determine individual prey vigilance. We combined behavioural data on individual vigilance of herbivores at waterholes with fine-scale spatiotemporal data from 27 African lions, Panthera leo, fitted with GPS radiocollars to test whether individual prey vigilance increases when predators are in the vicinity and whether this relationship is influenced by group size and presence of other herbivores. The study was conducted on giraffe, Giraffa camelopardalis, greater kudu, Tragelaphus strepsiceros, and plains zebra, Equus quagga, in Hwange National Park, Zimbabwe, between mid-September and mid-November 2008. Kudu was the only species to adjust its vigilance level significantly in the presence of lions, arguably owing to its higher contribution to lion diet in Hwange. Kudu devoted a significantly higher proportion of time to vigilance when lions were in the vicinity. Furthermore, the proportion of time spent on individual vigilance decreased as group size increased during the approach and drinking phases, particularly when lions were in the vicinity. Finally, the presence of other herbivores at the waterhole enabled kudu to spend less time vigilant while drinking. These adjustments involved changes in the length of vigilance bouts, but not in their frequency. Our study suggests that the interplay between the context (group size, presence of other prey) and the immediate presence of predators determines the level of vigilance in prey.

The devil is in the dispersers: predictions of landscape connectivity change with demography

Summary 1. Concern about the effects of habitat fragmentation has led to increasing interest in dispersal and connectivity modelling. Most modern techniques for connectivity modelling have resistance surfaces as their foundation. However, resistance surfaces for animal movement are frequently estimated without considering dispersal, despite being the principal natural mechanism by which organisms move between populations. 2. We collected Global Positioning System data over 10 years from 50 African lions Panthera leo (11 male natal dispersers, 20 adult males and 19 adult females) and used a path level analysis to parameterize demographic-specific resistance surfaces for the Kavango Zambezi Transfrontier Conservation Area (KAZA) in Southern Africa. 3. Lion path selection varied according to demographic grouping: adult females were most averse to risky landscapes such as agro-pastoral lands, towns, areas of high human density and highways. Male natal dispersers were the least-risk averse suggesting they are potentially the most prone demographic to human–lion conflict. Adults of both sexes selected bushed grassland and shrubland habitats and avoided woodland. Male natal dispersers displayed the opposite trend suggesting con-specific avoidance and/or suboptimal habitat use. 4. We used the resistance surfaces to calculate factorial least-cost path networks for each demographic-specific resistance surface and present results that show substantial differences between predicted patterns of connectivity for male natal dispersers, adult females and adult males. 5. Synthesis and applications. Resistance surfaces are widely used to create connectivity models, which are promoted for use by conservation managers. Our results suggest that the demographic category used to parameterize resistance surfaces may lead to radically different conclusions about connectivity. Failure to include dispersing individuals when parameterizing resistance surfaces intended for connectivity modelling may lead to erroneous conclusions about connectivity and potentially unsound management strategies.

Size, rarity and charisma: Valuing African wildlife trophies

We explore variation in the prices paid by recreational hunters of trophy animals in Africa and its possible causes, including perceived rarity. Previous work has raised the possibility that extinction can result if demand rises fast enough as a species becomes rarer. We attempt to disentangle this from other inter-correlated influences affecting price. Species with larger body sizes and larger trophies were more valuable. Value increased less steeply as a function of size for bovids than for felids and the effect was consistent across countries. Power laws, ubiquitous in physical and social systems, described the trends. The exponent was approximately 0.4 for bovids, compared with approximately 1.0 for felids. Rarity (as indexed by IUCN score) influenced the value of bovid trophies – price was higher for species in categories denoting higher global threat. There was substantial variation in price among and within families not explained by either size or rarity. This may be attributable to a ‘charisma’ effect, which seems likely to be a general attribute of human perceptions of wildlife. Species where prices were higher than predicted by size or rarity are ranked high in published accounts of desirability by hunters. We conclude that the valuation of these species is explicable to a large extent by body size and perceived rarity, and that differences in valuation between taxonomic groups are related to less easily quantified ‘charisma’ effects. These findings are relevant for conservationists considering the threat status of species exploited in open access markets, and where license quotas are adjusted in response to changes in perceived rarity.

Seasonal diet and prey preference of the African lion in a waterhole-driven semi-arid savanna.

Large carnivores inhabiting ecosystems with heterogeneously distributed environmental resources with strong seasonal variations frequently employ opportunistic foraging strategies, often typified by seasonal switches in diet. In semi-arid ecosystems, herbivore distribution is generally more homogeneous in the wet season, when surface water is abundant, than in the dry season when only permanent sources remain. Here, we investigate the seasonal contribution of the different herbivore species, prey preference and distribution of kills (i.e. feeding locations) of African lions in Hwange National Park, Zimbabwe, a semi-arid African savanna structured by artificial waterholes. We used data from 245 kills and 74 faecal samples. Buffalo consistently emerged as the most frequently utilised prey in all seasons by both male (56%) and female (33%) lions, contributing the most to lion dietary biomass. Jacobs’ index also revealed that buffalo was the most intensively selected species throughout the year. For female lions, kudu and to a lesser extent the group “medium Bovidae” are the most important secondary prey. This study revealed seasonal patterns in secondary prey consumption by female lions partly based on prey ecology with browsers, such as giraffe and kudu, mainly consumed in the early dry season, and grazers, such as zebra and suids, contributing more to female diet in the late dry season. Further, it revealed the opportunistic hunting behaviour of lions for prey as diverse as elephants and mice, with elephants taken mostly as juveniles at the end of the dry season during droughts. Jacobs’ index finally revealed a very strong preference for kills within 2 km from a waterhole for all prey species, except small antelopes, in all seasons. This suggested that surface-water resources form passive traps and contribute to the structuring of lion foraging behaviour.

Environmental determinants of habitat and kill site selection in a large carnivore: scale matters

Abstract Scale influences habitat selection. We used data from 30 global positioning system radiocollared lions (Panthera leo) collected between 2003 and 2007 in Hwange National Park, Zimbabwe, and information from 227 locations where lions had made kills, to assess how lions select habitat at 3rd-order habitat selection (selection of habitats within home ranges) and 4th-order habitat selection (selection of kill sites within the habitats used). Within home range, lions preferentially selected bushed grasslands and sites close to water holes, which are both characterized by high prey abundance. However, lions preferentially killed in thickets, where prey abundance was not the highest but where prey catchability may be higher because of dense vegetation. Our results support the suggestion that there are different determinants of habitat selection at different scales with prey abundance being the main driver of habitat selection at 3rd-order and prey catchability the main driver at 4rth-order habitat selection.

Cecil: A Moment or a Movement? Analysis of Media Coverage of the Death of a Lion, Panthera leo

Simple Summary We provide chronology of events following the death of a lion nicknamed “Cecil” and analyse the global media coverage of the event spatially and temporally. We recruited a media monitoring company to explore patterns in both social and editorial media globally, regionally and by country. The number of articles in the editorial media mentioning Cecil the lion peaked at 11,788 on 29 July. There was remarkable global synchrony in this “spike”, so the world media appeared to respond as a globalised entity. We used media saturation, a relative measure of the number of mentions of the Cecil story, as a proxy for estimating the level of interest in the Cecil story. Regionally, saturation levels were high in North America. Interest was also high in Australia and parts of South America and Africa. This opposes the common assumption that interest in the Cecil story was the prerogative of wealthy nations. The social media response to Cecil’s death, was much larger than that in the editorial media in terms of the number of mentions of Cecil (87,533 mentions), but the time to the peak was very similar to that of the editorial media. We compared the development of coverage of the event in the three largest social media platforms (Facebook, Twitter and YouTube) to see whether they played identifiably different roles in the development of the story through time. All peaked at the same time, so there was no evidence that any one platform was responsible for precipitating the spread of the story in advance of the others. The editorial and social media also peaked in synchrony, neither one being a forerunner or follower in the coverage of the Cecil story. Instead, our results reveal a highly interconnected media universe: with the story going viral synchronously across media channels and geographically across the globe over the span of about two days. We consider whether the preoccupying interest in Cecil displayed by the millions of people who followed the story may betray a personal, and thus potentially political, value not just for Cecil, and not just for lions, but for wildlife, conservation and the environment. If so, then for those concerned with how wildlife is to live alongside the human enterprise, this is a moment not to be squandered and one which might have the potential to herald a significant shift in society’s interaction with nature. Abstract The killing of a satellite-tagged male lion by a trophy hunter in Zimbabwe in July 2015 provoked an unprecedented media reaction. We analyse the global media response to the trophy hunting of the lion, nicknamed “Cecil”, a study animal in a long-term project run by Oxford University’s Wildlife Conservation Research Unit (WildCRU). We collaborated with a media-monitoring company to investigate the development of the media coverage spatially and temporally. Relevant articles were identified using a Boolean search for the terms Cecil AND lion in 127 languages. Stories about Cecil the Lion in the editorial media increased from approximately 15 per day to nearly 12,000 at its peak, and mentions of Cecil the Lion in social media reached 87,533 at its peak. We found that, while there were clear regional differences in the level of media saturation of the Cecil story, the patterns of the development of the coverage of this story were remarkably similar across the globe, and that there was no evidence of a lag between the social media and the editorial media. Further, all the main social media platforms appeared to react in synchrony. This story appears to have spread synchronously across media channels and geographically across the globe over the span of about two days. For lion conservation in particular, and perhaps for wildlife conservation more generally, we speculate that the atmosphere may have been changed significantly. We consider the possible reasons why this incident provoked a reaction unprecedented in the conservation sector.

Diet quality in a wild grazer declines under the threat of an ambush predator

Predators influence prey populations not only through predation itself, but also indirectly through prompting changes in prey behaviour. The behavioural adjustments of prey to predation risk may carry nutritional costs, but this has seldom been studied in the wild in large mammals. Here, we studied the effects of an ambush predator, the African lion (Panthera leo), on the diet quality of plains zebras (Equus quagga) in Hwange National Park, Zimbabwe. We combined information on movements of both prey and predators, using GPS data, and measurements of faecal crude protein, an index of diet quality in the prey. Zebras which had been in close proximity to lions had a lower quality diet, showing that adjustments in behaviour when lions are within short distance carry nutritional costs. The ultimate fitness cost will depend on the frequency of predator–prey encounters and on whether bottom-up or top-down forces are more important in the prey population. Our finding is the first attempt to our knowledge to assess nutritionally mediated risk effects in a large mammalian prey species under the threat of an ambush predator, and brings support to the hypothesis that the behavioural effects of predation induce important risk effects on prey populations.

Questionable policy for large carnivore hunting

U.S. wolf-hunting policies do not align with ecological theory or data U.S. wolf-hunting policies do not align with ecological theory or data