Bruce Richard Page

University of KwaZulu-Natal | ukzn · School of Life Sciences

Elephants occupy a dietary niche distinct from that of smaller browsers by consuming fibrous bark and root tissues along with leaves. They have the capacity to directly induce plant mortality through toppling, pollarding, uprooting, or debarking woody plants. African elephants are recognized to be among the major drivers of the structure and compos...

Background Hunting of male African elephants may pose ethical and risk concerns, particularly given their status as a charismatic species of high touristic value, yet which are capable of both killing people and damaging infrastructure.Methodology/Principal Findings We quantified the effect of hunts of male elephants on (1) risk of attack or damage...

Elephant are considered major drivers of ecosystems, but their effects within small-scale landscape features and on other herbivores still remain unclear. Elephant impact on vegetation has been widely studied in areas where elephant have been present for many years. We therefore examined the combined effect of short-term elephant presence (< 4 year...

The potential long-term influences of mesobrowsers versus those of savannah elephants on woodland dynamics have not been explored. This may be a critical omission especially in southern African savannahs, where efforts to preserve existing woodlands are typically directed at elephant management. We describe a simple browse-browser model, parameteri...

Management often bases decisions on estimates of animal density and population size. Aerial sampling is expensive whilst current ground methods, noticeably Distance sampling, assume a single detection function for each habitat and that visibility in a given habitat type declines in a smooth, increasing manner with distance from the observer. If the...

The initial settlement of the Greater Mapungubwe Landscape by Zhizo ceramic-producing farmers around AD 900 is said to be linked to the large elephant population that the region once supported. Elephant ivory was used in the Indian Ocean trade network to obtain exotic trade goods such as glass beads and cloth. However, there has been no attempt to...

Althoughwhat drives the abundance and habitat selection of ungulates is a long-standing question, coherent datasets investigating the influences of rainfall, competition and fire on ungulates are unusual. Over 4 y we carried out extensive monthly road transects in Ithala Game Reserve, South Africa, to determine the demographics and habitat occupanc...

Trophy hunting of African elephant is often implemented as an income generator for communities surrounding protected areas. However, the sustainability of hunting on elephant populations, especially with regards to international cross-border populations has not previously been evaluated. We assessed the effects of trophy hunting on the population d...

Resource depletion and associated increases in interspecific competition are likely to influence differential habitat usage amongst a guild. We tested some prominent theoretical concepts using observed differences in seasonal habitat use amongst the savanna browser guild (elephant, giraffe, impala, kudu and nyala) in Hluhluwe-iMfolozi Park, South A...

The potential long-term influences of mesobrowsers versus those of savannah elephants on woodland dynamics have not been explored. This may be a critical omission especially in southern African savannahs, where efforts to preserve existing woodlands are typically directed at elephant man-agement. We describe a simple browse–browser model, parameter...

Large trees, as keystone structures, are functionally important in savanna ecosystems, and low recruitment and slow growth makes their conservation important. Understanding factors influencing their distribution is essential for mitigation of excessive mortality, for example from management fires or large herbivores. We recorded the locations of la...

Research has increasingly established that mesoherbivores influence the regeneration of woody plants. However the relationship between mesoherbivore density and degree of impact, and the spatial component of this impact, has not been well established. Using a novel sampling design, we assessed in iMfolozi Park, South Africa, the impact of impala (A...

The vegetation dynamics of the savanna ecosystem are driven by complex interactions between biotic and abiotic factors, and thus are expected to exhibit emergent properties of biocomplexity. We explore the relative importance of static and dynamic drivers in explaining the patterns of mortality of large trees in the Kruger National Park, South Afri...

Elephant and fire are considered to be among the most important agents that can modify the African savanna ecosystem. Although the synergistic relationship between these two key ecological drivers is well documented, it has proved much more difficult to establish the relative effects they have on savanna vegetation structure at a fine-scale over ti...

The large spectrum of existing literature on browser-woodland dynamics, both from savanna and temperate biomes, converges towards concluding that all browsers importantly impact woody plants. In this context a crucial question in the current debate about reintroducing elephant culling, is whether the long-term effects of elephants and mesobrowsers...

To clarify the potential influence of different browsers in the same guild on woody vegetation, dietary overlap and separation between elephant, giraffe, kudu, nyala and impala was assessed in Hluhluwe-iMfolozi Park, South Africa. Woody species browsed, browsing heights, plant-parts browsed and browsing versus grazing were recorded over 2 y by dire...

Manipulations of herbivores in protected areas may have profound effects on ecosystems. We examine short-term effects on tree species assemblages and resource utilization by a mesoherbivore and small-size herbivores (ungulates <20 kg) in Sand Forest, after browsing release from a megaherbivore (elephant), or both a mega- and mesoherbivore (nyala),...

In this paper we analyse the daytime movements of African elephants (Loxodonta africana) in different habitats in the Pongola Game Reserve, South Africa. On average adult males moved faster than females in all habitat types except when grouped together (then females moved at the faster male pace). Elephants demonstrated distinct movement patterns i...

Regression analyses for tree abundance vs. tree diameter. (DOC)

Herbivory by megaherbivores on woody vegetation in general is well documented; however studies focusing on the individual browsing effects of both mega- and mesoherbivore species on recruitment are scarce. We determined these effects for elephant Loxodonta africana and nyala Tragelaphus angasii in the critically endangered Sand Forest, which is res...

1. Elucidation of the mechanism determining the spatial scale of patch selection by herbivores has been complicated by the way in which resource availability at a specific scale is measured and by vigilance behaviour of the herbivores themselves. To reduce these complications, we studied patch selection by an animal with negligible predation risk,...

Elephant and impala as intermediate feeders, having a mixed diet of grass and browse, respond to seasonal fluctuations of forage quality by changing their diet composition. We tested the hypotheses that (1) the decrease in forage quality is accompanied by a change in diet from more monocots in the wet season to more dicots in the dry season and tha...

Differences in intraspecific foraging strategies have been documented between sexes of strongly dimorphic large herbivore species. Body size implications on diet quality requirements, however, can be extended to within-species age-specific comparisons. We investigated the hierarchical separation of foraging behavior at the scale of plant type, plan...

1. Understanding and accurately predicting the spatial patterns of habitat use by organisms is important for ecological research, biodiversity conservation and ecosystem management. However, this understanding is complicated by the effects of spatial scale, because the scale of analysis affects the quantification of species–environment relationship...

The allometric relationships of body size play a principle role in determining how large herbivores respond to the marked spatial and temporal heterogeneity of the savanna biome. Using location data collected over an 8-year period from five distinct study sites, we investigated the influence of environmental variation (using phenological and rainfa...

Re-introduced African elephant (Loxodonta africana Blumenbach) populations are growing at very high rates in many of southern Africa's reserves, have attained densities higher than previously thought possible and may be exhibiting irruptive growth. Active management of such populations is necessary to prevent the potentially negative effects on hab...

Aim Artificial water points are often used in protected savanna ecosystems to maintain populations of large herbivores. However, these interventions lead to increased ranging and foraging pressure and can negatively impact important habitats and species. This study investigated the influence of artificial water provision on the foraging and movemen...

Mammalian herbivores adopt foraging strategies to optimize nutritional trade-offs against restrictions imposed by body size, nutritional requirements, digestive anatomy, physiology, and the forage resource they exploit. Selective or generalist feeding strategies scale with body size across species. However, within species, where constraints should...

1. Globally, both climatic patterns and nitrogen deposition rates show directional changes over time. It is uncertain how woody seedlings, which coexist with herbaceous plants in savannas, respond to concurrent changes in water and nutrient availability. 2. We investigated competition effects between herbaceous vegetation and tree seedlings (Coloph...

Globally, both climatic patterns and nitrogen deposition rates show directional changes over time. It is uncertain how woody seedlings, which coexist with herbaceous plants in savannas, respond to concurrent changes in water and nutrient availability. We investigated competition effects between herbaceous vegetation and tree seedlings ( Colophosper...

Acquiring greater understanding of the factors causing changes in vegetation structure - particularly with the potential to cause regime shifts - is important in adaptively managed conservation areas. Large trees (≥5 m in height) play an important ecosystem function, and are associated with a stable ecological state in the African savanna. There is...

Elephant are believed to be one of the main ecological drivers in the conversion of savanna woodlands to grassland. We assessed the impacts of elephant on large trees (≥5 m in height) in the southern section of the Kruger National Park. Tree dimensions and utilization by elephant were recorded for 3082 individual trees across 22 transects (average...

The effect of bull hunts on movement dynamics. We assess bulls and breeding herds associated with the hunt event in terms of their distance and direction moved relative to the hunt site for the ten-day period before and after the hunt. XB = mean distance to hunt site before hunt. XA = mean distance to hunt site after hunt. Mann-Whitney U tests were...

Supporting Information text file including table for Burke et al. (0.05 MB DOC)

Elephant are believed to be one of the main ecological drivers in the conversion of savanna woodlands to grassland. We assessed the impacts of elephant on large trees (≥5 m in height) in the southern section of the Kruger National Park. Tree dimensions and utilization by elephant were recorded for 3082 individual trees across 22 transects (average...

The activity budget hypothesis is 1 of 4 main hypotheses proposed to explain sexual segregation by large herbivores. Because of their smaller body size, females are predicted to have higher mass-specific energy requirements and lower digestive efficiency than males. As a result, females are expected to forage longer to satisfy their nutritional dem...

In predator-free large herbivore populations, where density-dependent feedbacks occur at the limit where forage resources can no longer support the population, environmental catastrophes may play a significant role in population regulation. The potential role of fire as a stochastic mass-mortality event limiting these populations is poorly understo...

Hunting of male African elephants may pose ethical and risk concerns, particularly given their status as a charismatic species of high touristic value, yet which are capable of both killing people and damaging infrastructure. We quantified the effect of hunts of male elephants on (1) risk of attack or damage (11 hunts), and (2) behavioural (movemen...

The historical regulation of African elephant Loxodonta africana populations could provide guidelines for management efforts and decisions in areas where elephant numbers are now increasing. However, there are few detailed records of the natural mortality processes of the past. Therefore, we modelled elephant population growth to evaluate possible...

T HE PREVAILING INCREASE IN ELEPHANT numbers across areas of southern Africa raises concern for their impact on biological diversity. Several approaches to elephant management focus on limiting numbers to alleviate these consequences. However, landscape fragmentation, fences, water supple-mentation as well as the shape and size of some conservation...

Elephants (Loxodonta africana) exhibit pronounced sexual dimorphism, and in this study we test the prediction that the differences in body size and sociality are significant enough to drive divergent foraging strategies and ultimately sexual segregation. Body size influences the foraging behaviour of herbivores through the differential scaling coef...

Sexual segregation is a commonly observed phenomenon in dimorphic ungulates, which has been categorised into two distinct components: social segregation and habitat segregation. In this study we investigated whether elephants were sexually segregated at the habitat scale. The locations of 12 family groups and 16 males, in three distinct populations...

HOW TO RESPOND TO GROWING ELEPHANT numbers in the Kruger National Park and elsewhere in southern Africa continues to be a contentious issue. In contrast to the public perception, scientists have attained a high degree of consensus on the ecological basis for such decisions. In this article we summarize these ecological principles and the management...

Using woody communities in a South African game reserve as an example, we have developed a group prediction technique based on total indicator value to aid in the interpretation of a TWINSPAN analysis. Our total indicator value method TIVM is based on Dufrêne and Legendre's indictor value method (IVM). IVM is widely used to identify indicator speci...

The ranging behaviour and habitat occupancy by three elephant groups (cow herd, bulls, and an orphan group) were studied over a two-year period in a small, fenced reserve. No summer dispersal was observed. Distinct seasonal home ranges were exhibited for all groups, with the summer (wet season) ranges being smaller than the winter (dry season) rang...

Elephants have been, and continue to be, introduced to small conservation areas in South Africa despite concerns that elephants may adversely affect the vegetation for other herbivores, reduce the aesthetic value of the landscape for tourism, and fundamentally reduce local blodiversity. The rate at which elephant populations grow is essential knowl...

The ranging behaviour and habitat occupancy by three elephant groups (cow herd, bulls, and an orphan group) were studied over a two-year period in a small, fenced reserve. No summer dispersal was observed. Distinct seasonal home ranges were exhibited for all groups, with the summer (wet season) ranges being smaller than the winter (dry season) rang...

By 2001, elephants had been translocated (mainly from Kruger National Park) to 58 small, fenced reserves in South Africa. All but two introductions took place since 1989. We document important aspects of the population dynamics of elephants in these reserves using data collected in a survey conducted in 2001. The mean population size was 45 elephan...

By 2001, elephants had been translocated (mainly from Kruger National Park) to 58 small, fenced reserves in South Africa. All but two introductions took place since 1989. We document important aspects of the population dynamics of elephants in these reserves using data collected in a survey conducted in 2001. The mean population size was 45 elephan...

The impact of elephant and other browsers may be magnified when they are restricted within small, fenced reserves. These reserves are becoming commonplace in southern Africa. The composition and structure of the woody vegetation of a portion of the 30 000 ha Ithala Game Reserve, South Africa, was monitored annually from 1992 to 2000. Woody species...

Summary 1. Understanding and accurately predicting the spatial patterns of habitat use by organisms is important for ecological research, biodiversity conservation and ecosystem management. How�ever, this understanding is complicated by the effects of spatial scale, because the scale of analysis affects the quantification of species–environment rel...

Musth is a state of heightened sexual and aggressive activity in male elephants. Between 1992 and 1997, young orphaned musth male African elephants (Loxodonta africana) that had been introduced to Pilanesberg, South Africa, killed more than 40 white rhinoceros (Ceratotherium simum). The killing ceased after six older male elephants were introduced...

A model is developed and parameterized to represent an ecological system consisting of elephants, abundant trees and rare trees, which represents a reasonable approximation of ecosystem scenarios in which elephants are found. Parameters are set in realistic bounds and model simulation results are consistent with elephant densities measured in the w...

In 1976 Caughley proposed a simple predator–prey model for elephant–tree dynamics. To our knowledge no-one has attempted to assess this model against real data. The significance of Caughley’s model was to show that limit cycle behavior is possible for the elephant-tree system. Using realistic parameter estimates the paper emphasizes that, in fact,...