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Some upper trophic level predators, such as marine mammals, seabirds and large predatory fish have been shown to be useful sentinels for marine ecosystems. Through their demography, diet and foraging behaviour, ecosystem changes associated with climate change can be monitored. The local marine ecosystem at the Prince Edward Archipelago in the Southern Indian Ocean is heavily influenced by the position of the dynamic sub-Antarctic front (SAF) that varies inter-annually in terms of its influence on the local environment. If the SAF migrates southwards, as climate change models have predicted, the abundance of autochthonous and allochthonous prey found within the vicinity of the archipelago will decrease and increase, respectively. We investigated the diet of an inshore forager at the archipelago, the gentoo penguin Pygoscelis papua, as a possible sentinel to the expected changes in the prey assemblages in local waters, due to the southward migration of the SAF. We collected stomach content samples from gentoo penguins, using the water off-loading technique, monthly over three years (1994–1996) and then annually during 2012, 2014 and 2015. Prey assemblages within the diet was found to coincide with the proximity of the SAF to the Prince Edward Archipelago as well as the annual life cycles of prey. Due to the plasticity these penguins exhibit in their diet and foraging behaviour, we suggest that they are important sentinel species for the local marine ecosystem of the Prince Edward Archipelago. Regular sample collection from these birds, albeit stomach content samples and/or tissues for stable isotope analysis, should be collected so that variability in the ecosystem can be easily monitored.

Animals sculpt landforms by physically altering the substrate. Many digging and burrowing animals are then considered zoogeomorphic agents. While the significance of soil disturbing species is well established, geomorphic impacts are rarely quantified for rock transporting species. The chacma baboon (Papio ursinus), a widespread and abundant primate throughout most of southern Africa south of the Zambezi, may be a zoogeomorphic agent through its role in rock displacement while foraging. We quantified baboon rock movement along belt-transects placed across a catena in a semi-arid Karoo environment in South Africa. Along each transect, we the counted the number of moved rocks and recorded their dimensions, mass and shape and related this to rock (i.e., mass, shape) and landscape (i.e., hillslope, obstacles that hinder movement) features to assess the drivers of the extent of rock transport. Baboon rock movement was found to be extensive, ranging from 26 to 54,615 kg (10,967.2 ± 2300.9 kg) of rock material displaced per ha and year. The distance of rock movement was influenced by rock size (large rocks were displaced further) and rock shape (flat rocks were moved further, followed by angular and rounded rocks). Furthermore, slope influenced rock movement, with rocks displaced greater distances on steeper slopes. Baboon rock movement brought about a loss in potential energy and a change in landscape entropy through the net downward movement of rocks. We show that baboons play an important geomorphic role and probably serve as a keystone species as they are the only species in this environment to intentionally move rocks in this way. Because baboons are considered pests and are widely persecuted, their role in zoogeomorphic processes are vulnerable to being lost.

Life history changes may change resource use. Such shifts are not well understood in the dung beetles, despite recognised differences in larval and adult feeding ability. We use the flightless dung beetle Circellium bacchus to explore such shifts, identifying dung sources of adults using DNA metabarcoding, and comparing these with published accounts of larval dung sources. C. bacchus is traditionally considered to specialise on the dung of large herbivores for both larval and adult feeding. We successfully extracted mammal DNA from 151 adult C. bacchus fecal samples, representing 16 mammal species (ranging from elephants to small rodents), many of which are hitherto undescribed in the diet. Adult C. bacchus showed clear dung source preferences, especially for large herbivores inhabiting dense-cover vegetation. Our approach also confirmed the presence of cryptic taxa in the study area, and we propose that this may be used for biodiversity survey and monitoring purposes. Murid rodent feces were the most commonly fed-upon dung source (77.5%) for adult C. bacchus, differing markedly from the large and megaherbivore dung sources used for larval rearing. These findings support the hypothesis of life history-specific shifts in resource use in dung beetles, and reveal a hitherto unsuspected, but ecologically important, role of these dung beetles in consuming rodent feces. The differences in feeding abilities of the larval and adult life history stages have profound consequences for their resource use and foraging strategies, and hence the ecological role of dung beetles. This principle and its ecological consequences should be explored in other scarabaeids.

The moose (Alces alces) is a dominant large mammalian herbivore in the world’s boreal zones. Moose exert significant browsing impacts on forest vegetation and are therefore often at the centre of wildlife-forestry conflicts. Consequently, understanding the drivers of their foraging behaviour is crucial for mitigating such conflicts. Management of moose in large parts of its range currently largely ignores the fact that moose foraging is influenced by increasing populations of sympatric deer species. In such multispecies systems, resource partitioning may be driven by foraging height and bite size. Feeding competition with smaller species might replace larger species from the field layer and drive them towards higher foraging strata offering larger bites. This bite size hypothesis has been well documented for African ungulate communities. Based on a large diet DNA metabarcoding dataset we suggest that feeding competition from three smaller deer species (red deer Cervus elaphus, fallow deer Dama dama, and roe deer Capreolus capreolus) over Vaccinium shrubs in the forest field layer might drive moose towards increasing consumption of Scots pine (Pinus sylvestris) in Sweden. We found that in areas of high deer density, moose diets consistently contained less Vaccinium and higher proportions of pine over three spring periods. Utilization of these food items by the smaller deer species was either unaffected by deer density or, for Vaccinium showed the opposite pattern to moose, i.e., increases of proportions in the diet of roe and red deer with increasing deer density. Availability of pine and Vaccinium, measured as proportion of available bites, did not explain the observed patterns. Our results suggest that managing key food items like Vaccinium and the populations of smaller deer may play an important role in controlling browsing impacts of moose on pine.

Despite the importance of coarse woody debris (CWD) in woody ecosystems, conceptual frameworks of its dynamics currently exclude the role of the megaherbivores, focusing instead on the role of insects, disease, fire, wind and droughts. However, recognizing the ecological roles of the megaherbivores is one of the most urgent contemporary issues, particularly as their decline will likely have unanticipated outcomes at the ecosystem-level. Here we used sites with and without elephants in a semi-arid woodland ecosystem in South Africa to test whether elephants changed the quantitative and qualitative features of the CWD profile in relation to other wood producers. We show that elephants increased the abundance of CWD, influenced its quality by toppling mostly maturing trees, and changed the distribution of large woody items along gentle hillslopes. Surprisingly, and despite the recognized importance of both CWD and elephants for biodiversity, there is almost no published data on the role of elephants in shaping wood-living communities by changing fallen woody debris dynamics. Our study contributes towards developing a broader conceptual framework of CWD dynamics that includes the role of megaherbivores and provides a novel view of the ecological consequences of the loss of the Pleistocene megaherbivores. Our findings have important implications for CWD restoration efforts in transformed systems that previously supported megaherbivores.

Monitoring is meant to inform conservation authorities, yet managers often don't know when to respond to monitoring results. One of the reasons is that management often lacks consensus on monitoring thresholds for intervention. This results in aimless monitoring without a clear directive on when monitoring indicates a trajectory towards an unacceptable state or impending change, which possibly necessitates intervention. Although experts rarely provide simple, measureable and quantifiable monitoring thresholds as required by management, they are often more comfortable expressing opinions on whether a specific area is desirable or not. This allows thresholds to be reverse engineered: by getting experts to identify sites as desirable and undesirable, field variables can subsequently be measured to derive the boundary between subjectively identified desirable and undesirable states. Such a boundary provides a defendable point for management to assess and consider intervention. Here we describe the identification of monitoring thresholds by defining the limits of desirable canopy cover, derived from expert stakeholder preferences, in the Sundays Spekboom Thicket vegetation of the Addo Elephant National Park, South Africa. The park has experienced variable utilization intensity by large herbivores, especially elephant. For years managers have grappled with the question of what percentage shrub canopy cover is desirable as a management target, but science has failed to provide this. Using experts to assess pre-selected sites as desirable or undesirable across a range of canopy covers, we showed that a canopy cover of ∼65% (±15%) would be desirable for expert stakeholders. We then used satellite imagery to map canopy cover, providing managers for the first time with a large-scale map of canopy cover, indicating desirability status. This approach was useful for facilitating joint-decision making between conservation agencies and stakeholders on tangible indicators of achieving goals, and may be useful in fostering relationships, trust, mutual understanding and transparency, characteristics critical for managing complex socio-ecological systems.

Pellet counts are widely used to monitor ungulates but rely on the assumption that pellets of different species are correctly identified in the field. Recent studies question this assumption using DNA barcoding techniques to check field identification rates. For Europe, which is undergoing a rapid shift towards more diverse ungulate assemblages, such an assessment is still missing. Using DNA barcoding on 3889 fecal samples from nine ungulate species in four European countries, we found average field misidentification rates varied from 0.6% for horse (Equus ferus) to 41.1% for roe deer (Capreolus capreolus). Most identification errors occurred between similar-sized species from the same taxonomic family. For a subset of samples from Sweden, we looked at the effect of dung morphometry, observer experience, and season on species identification success. Dung morphometry clearly distinguished moose (Alces alces) but not red (Cervus elaphus), roe, and fallow deer (Dama dama). Experienced observers performed better than novices for red and fallow deer although still making significant identification errors (26% and 17% incorrectly identified). Identification success was higher during spring and winter ( $$ \overline{x} $$ = 86%) than summer and autumn ( $$ \overline{x} $$ = 74%). We question pellet counts as an accurate monitoring tool where similar-sized species coexist and monitoring relates to the whole community. For this increasingly common situation across Europe, DNA testing or camera traps may be a better alternative. Pellet counts remain useful where only few species with clearly different dung morphology coexist (e.g., moose and roe deer) or when focused on species with distinctive dung morphology (e.g., moose).

Distribution data form the basis of the study of zoo-geography, which has applications in, inter alia, ecology and conservation. Written records were used to estimate the distribution patterns of some of the medium- to large-sized terrestrial mammals in central, southern and western South Africa, and neighbouring Lesotho, during the early historical period (late 1400 s to the 1920s). The sources of these records comprise mainly published or unpublished letters, journals, diaries or books written by literate pioneers – notably various missionaries, explorers, travellers, naturalists, military personnel, big game hunters and agro-pastoralists. The classification (according to record type) of the written records in key publications was standardised, and records overlooked by them are taken into account. Interpretation of the spatial patterns provided by the written records was aided by reference to supporting information, in the form of qualifying palaeontological, zoo-archaeological and museum records. Writ...

Antarctic (Arctocephalus gazella) and Subantarctic (A. tropicalis) fur seals are important predators in the Southern Ocean. Marion Island (southern Indian Ocean) hosts the largest sympatric breeding populations of these two species. Environmental and population changes here over two decades may have influenced their diet and trophic interactions. To quantify diet, we analysed prey remains in scat samples from Antarctic (661 scats) and Subantarctic (750 scats) fur seals collected at Marion Island (2006–2010). We assessed diet composition over time and calculated dietary overlap. The diet of both species was dominated by fish prey (98.2% and 99.4% of prey items), mainly myctophids. Antarctic fur seals consumed small numbers of penguins, cephalopods and crustaceans. In Subantarctic fur seal scats, crustaceans and cephalopods were rare and penguin remains were absent. The diets of the two species overlapped substantially (Pianka’s index = 0.98), however, small but significant differences in the relative proportions of prey were evident. Seasonal and annual diet changes suggest that their diet is similarly influenced by patterns of local prey availability and abundance. Despite substantial changes in the population size and trajectory of Antarctic and Subantarctic fur seals – which would be expected to influence trophic interactions between them – comparing our data to those from earlier studies (1989–2000) did not reveal significant long-term dietary changes in either species.

The question of how many herbivores an area can support for long-term persistence is fundamental to managing wildlife in increasingly fragmented landscapes. Species-specific spatial requirement information is scarce, so many studies have used models to predict carrying capacities for indigenous herbivores based on forage productivity estimates and metabolic requirements of the herbivores. Testing such models against empirically derived observations is, however, rare in the peer-reviewed literature. We modeled predicted relative abundances of the medium- to large-sized herbivore community of a reserve in the semi-arid eastern Karoo, South Africa, following Boshoff et al. (2001, 2002a). We also addressed the overestimation abundance of small species by incorporating an adjustment factor based on the relationship between body size and population metabolic rate. We tested both model's outputs against empirically derived game count data for the same herbivore community which revealed significant differences in species relative abundances predicted by the two models. Habitat-specific regression analyses revealed that incorporating a population metabolism adjustment factor into the model resulted in a generally better fit than the original model. Furthermore, the model performed best for apparently structurally simple habitats. These results support the use of forage-based productivity models to estimate potential abundances of indigenous herbivores.

Despite the apparent dual role of elephant Loxodonta africana in shaping the food niches of large herbivores, empirical studies focus on their role in facilitating foraging opportunities, while declining resource opportunities (a necessary requirement for competition) are rarely quantified. Our study investigates the relative importance of elephant in these processes by quantifying potential browsing opportunities (using total and preferred biomass, between-bite distances and bite mass) for black rhinoceros Diceros bicornis along a gradient of elephant utilization in the succulent thickets of the Addo Elephant National Park, South Africa. We show that browse biomass and potential between-bite harvest rates initially increase with the intensity of elephant utilization through the formation and spread of elephant pathways in otherwise impenetrable thicket. At the maximum, modeled estimates of total and preferred biomass are on average 223 percent and 254 percent higher, respectively, than that recorded in the absence of elephant (Exclosures); potential between-bite harvest rates are 75 percent higher. With continued elephant utilization, however, browse biomass declines and between-bite distances increase as the pathways expand and coalesce and canopy height declines. Our model of the change in potential browsing opportunities for rhinoceros reflects the accumulated effects of elephant over time, i.e., the effects accumulate until the relationship switches from increased to reduced availability. With this we demonstrate the key role of elephant for rhinoceros foraging, linked to a potential loss of this role at higher levels of utilization.

Maintaining key ecological processes is a strong argument for conserving biodiversity, and this should extend to preventing the local extinction of keystone species that are otherwise common. Seed dispersal is such a process and chacma baboons (Papio ursinus ursinus) may facilitate seed dispersal, but currently suffer range contractions in South Africa. Between April 2016 and February 2017, we collected a total of 122 chacma baboon scat samples in a semi-arid subtropical thicket, South Africa, and identified food items and seeds from the scats. We show that chacma baboons are omnivores, able to disperse at least 24 different seed species. This is a wider range of seed species than those dispersed by a broad range of birds, reptiles or other mammals in subtropical thicket, and nearly five times that dispersed by domestic goats (Capra hircus). This suggests that baboons are key seed dispersers, whose role might not be substituted by goats. We believe that baboons may become more important seed dispersers in arid subtropical thicket as climate change alters the distributional ranges of plant communities. This important role as endo-zoochores highlights the need to conserve, rather than persecute, chacma baboons.

Summary 1. The responses of small ruminants to changing food availability may vary from a broadening of the diet with declining availability, as predicted by optimality theory, to the maintenance of a restricted, selected diet, as predicted by the body-size constraint hypothesis. 2. We test these conflicting predictions by assessing the dietary responses of the Cape grysbok Raphicerus melanotis, a near-endemic to the Cape Floristic region, South Africa, to changes in the availability of a key forage species (i.e. Australian Acacia sp.). We predicted that the removal of alien Acacias would cause a broadening of the diet, and the consumption of previously avoided species, despite the selectivity imposed by their small body size. We used faecal analyses to describe grysbok diet and assessed diet quality through faecal quality analyses. 3. Results show that grysbok are highly selective browsers, able to change their diet and dietary preferences in response to changes in food availability. Animals included additional species in the diet in the absence of alien Acacias, altered their principal dietary items, broadened foraging strategies to include grass and some previously avoided species became preferred in the absence of Acacias. These dietary changes were effective in maintaining dietary protein intake, and caused a reduction in fibre intake in the absence of Acacias. 4. The data do not support the body size constraint hypothesis which is thought to impose a limit on the ability of small ruminants to select additional dietary species. 5. These data represent the first quantification of extensive grazing (up to 51% of the diet) by a species considered a browser. These findings support the prediction of optimality theory, whereby animals faced with a loss of important food items broaden their diet to include previously avoided species.

The views of visitors to national parks provide an important source of information to guide park planners and managers. A visitor questionnaire study was conducted in 2004 and 2005 in the Addo Elephant National Park, South Africa. A profile of the respondents, as well as records of their views on a number of park-related conservation and management issues, and of their observations of large and charismatic species (the ‘Big Five’) was compiled. The study clearly showed that national parks are important destinations for an African wildlife experience, along with other natural attractions that they have to offer. It also highlighted the scope for further visitor education, specifically aimed at improving the quality of their visits to the park. The relationship between elephant (Loxodonta africana) density and level of viewing success by visitors requires further investigation. Since the reintroduction of large predators, especially lion (Panthera leo), in the early 2000s, the daytime sighting rate of buffa...

Although elephants are recognized as keystone species, the mechanisms of their impacts on biodiversity and community structure are rarely identified. In the Addo Elephant National Park (AENP), South Africa, elephant Loxodonta africana herbivory is apparently responsible for a significant reduction in plant richness, especially among the regionally rare and endemic small succulent shrubs and geophytes (Important Plants). We used faecal analysis to investigate the utilization of Important Plants in elephant diet in the AENP. Ninety plant species were identified in the diet. Only 14 of the 77 (c. 18%) Important Plants previously thought particularly vulnerable to elephant browsing occurred in the diet, while at least 6% of species for which there are data were avoided. This refutes the generally held belief that elephant herbivory is the major driver of decline among Important Plants, and emphasizes the likely contribution of other mechanisms (e.g. knock-on effects, trampling, zoochory, etc.) to this phenomenon. The accurate prediction of impacts caused by elephants in the AENP and elsewhere, therefore requires an understanding of these previously marginalized mechanisms. By demonstrating appropriate cause-and-effect relationships between elephants and ecosystem change, we will be able to move beyond assuming that all the observed changes are due to elephant herbivory.

The diet of black rhinoceros (Diceros bicornis minor) has been the subject of a number of studies in various regions but information for the central bushveld region is sparse. This communication shows a number of woody species utilized by black rhino in this region and identified by means of microhistological faecal analysis. A total of 18 species were identified from the samples collected.

The diet of buffalo (Syncerus coffer) and Burchell's zebra (Equus burchelli) was investigated in the Addo Elephant National Park to test the hypothesis that the shortage of grass associated with thicket vegetation results in grazers increasing the proportion of dicotyledonous plant species in their diet. Diet composition, estimated from faecal analysis, indicated that 19 and 21 plant species were identified in the faeces of zebra and buffalo, respectively. Buffalo proved to have a higher percentage dicotyledonous (28.1 vs. 8.5 ) and lower percentage monocotyledonous (71.9 vs. 91.5 ) species in their diet than zebra. The grass Eragrostis curvula was found to be the dominant food item for both buffalo (18 of diet) and zebra (39 of diet) during the period of study. The present study indicated that a great proportion of the buffalo diet does in fact consist of grass, thereby refuting the perception that the Addo buffalo are primarily browsers. Both buffalo and zebra are specialised grazers and unsuited to a diet of browse. The probability of dietary shift by these grazers in the grass limited thicket vegetation is therefore challenged.

Throughout the world, terrestrial mammals are hunted for sport, subsistence and population control, providing a significant source of meat and income to communities (Milner et al. 2007). The game ranching industry in South Africa relies heavily on trophy hunting as a primary source of income (du Toit & van Rooyan 2002), and hence may be subject to manipulation that could increase revenue. The industry is growing rapidly, and steps need to be taken to ensure that this industry is sustainable, and is firmly grounded in science with effective government policy. In a recent article in South African Journal of Wildlife Research, von Brandis & Reilly (2008, hereafter vB&R) claim that significant spatial variation exist in the trophy quality (a function of horn size) of ungulates in South Africa and advocate the importance of a national trophy quality monitoring programme in order to control potential manipulation of trophy populations.

The issues around elephant management are complex and heavily value laden (Biggs et al., 2008) and should therefore be based on robust science and approached with considerable caution where uncertainties exist. We, therefore, welcome the opportunity to expand on the debate around the drivers of the decline among Important Plants (IP) in the Addo Elephant National Park (AENP; Landman, Kerley & Schoeman, 2008), followingMidgley’s (2009) contribution. We are, however, not supportive of his conclusion that elephants should be damned without evidence of their causative involvement in the decline of IP, but rather reiterate the need to understand the mechanisms of this decline. In developing his conclusion, Midgley (2009) offers some arguments that apparently bring into question the results presented. He firstly questions the applicability of microhistological faecal analysis for diet description, offering an opinion as to the disproportionate retention of grass material over other plant species. This technique has been extensively validated (e.g. Hansen, Peden & Rice, 1973; Todd & Hansen, 1973; Johnson & Wofford, 1983), although admittedly not for hindgut fermenters, such as elephant. Given their relatively poor digestion compared with ruminants, it is however reasonable to expect that elephants would suffer fewer such biases than the ruminants on which these validations are based. Furthermore, it is revealing that some of the species which Midgley (2009) suggest should not be well represented (species with ‘swollen stems or with succulent leaves’ – represented in this study by members of the Asphodelaceae, Crassulaceae, Euphorbiaceae, Portulacaceae and Viscaceae families) are actually very well represented in the estimated diet (contributing c. 15%). The implication that grasses would be overrepresented is also not supported by the data that show relatively little grass (in relation to what is available) in the diet (c. 34%). Finally, Landman et al. (2008) point out that the results of these analyses concur well with the diet described by direct observation. Based on the above, we are not convinced that these diet data should be discarded. Midgley (2009) then correctly points out that elephant impacts are not limited to what they eat. This is supported by research in the AENP. For example, Paley (1997) estimated that more than half of the equivalent of elephant daily food requirements was discarded during the feeding process, while Lessing (2007) showed that elephants discarded c. 25% of harvested forage material (Kerley et al., 2008). However, this discarded material is typically from large plants on which elephant feed robustly. We suspect that this would not be the case with the small plants typical of the IP. This does, however, not change the conclusion regarding the role of elephant herbivory. We agree with Midgley’s (2009) next point regarding the response of plants to elephant herbivory, and this has been pointed out elsewhere (Kerley et al., 2008). He makes an excellent point in suggesting that plant responses, plant growth rates and the total biomass killed by elephant needs to be determined. It should also, however, be recognized that although they are the dominant herbivores in terms of biomass (e.g. Stuart-Hill, 1992), elephants are not the only herbivores in the AENP. Is it, therefore, valid to blame only the elephants for the decline in IP, or focus exclusively on Journal of Zoology

The conservation management of southern Africa's elephants focuses on identifying and mitigating the extent and intensity of impacts on biological diversity. However, variation in the intensity of elephant effects between elements of biodiversity is seldom explored, which limits our ability to interpret the scale of the impacts. Our study quantifies >50 years of impacts in the succulent thickets of the Addo Elephant National Park, South Africa, contrasting hypotheses for the resilience of the canopy shrubs (a key functional guild) to elephants with those that argue the opposite. We also assess the impacts between elements of the community, ranging from community composition and structure to the structure of individual canopy species. We show the vulnerability of the canopy shrubs to transformation as the accumulated influences of elephants alter community composition and structure. The pattern of transformation is similar to that caused by domestic herbivores, which leads us to predict that elephants will eventually bring about landscape-level degradation and a significant loss of biodiversity. While we expected the canopy species to show similar declining trends in structure, providing insight into the response of the community as a whole, we demonstrate an uneven distribution of impacts between constituent elements; most of the canopy dominants exhibited little change, resisting removal. This implies that these canopy dominants might not be useful indicators of community change in thickets, a pattern that is likely repeated among the canopy trees of savanna systems. Our findings suggest that predicting elephant impacts, and finding solutions to the so-called “elephant problem,” require a broader and more integrated understanding of the mechanisms driving the changes between elements of biodiversity at various spatial and temporal scales.

The Australian Rhino Project (www.theaustralianrhinoproject.org) proposes importing 80 rhinos from South Africa to Australia by 2019 at a cost of over $US4 million, and the first six due to have been moved in 2016. This project has high profile supporters in the private sector, zoos and both governments, and is gaining major publicity through association with sporting teams and TedEx talks (http://www.theaustralianrhinoproject.org/index.php/news/blogs/11-news-and-blogs/242-ray-tedx). However, establishing extralimital populations of African rhinos is a very low priority conservation action, particularly given over 800 are already in captivity, and we argue this project diverts funds and expertise away from more important activities; the proposed captive conditions will lead to selection for domestic traits; the most likely species involved is the white rhino, which is the lowest priority rhino species for conservation; it removes a driver of in situ conservation; it does not focus on the critically endangered Asian rhino species; and it extends the historical exploitation of Africa's resources by colonial powers. There are also insufficient details in the public domain about the project for objective decision-making. We believe this is misdirected neo-colonial conservation and the policy support from both governments for this project should be reconsidered. This article is protected by copyright. All rights reserved

Surface water availability is a key driver of elephant impacts on biological diversity. Thus, understanding the spatio-temporal variations of these impacts in relation to water is critical to their management. However, elephant piosphere effects (i.e. the radial pattern of attenuating impact) are poorly described, with few long-term quantitative studies. Our understanding is further confounded by the complexity of systems with elephant (i.e. fenced, multiple water points, seasonal water availability, varying population densities) that likely limit the use of conceptual models to predict these impacts. Using 31 years of data on shrub structure in the succulent thickets of the Addo Elephant National Park, South Africa, we tested elephant effects at a single water point. Shrub structure showed a clear sigmoid response with distance from water, declining at both the upper and lower limits of sampling. Adjacent to water, this decline caused a roughly 300-m radial expansion of the grass-dominated habitats that replace shrub communities. Despite the clear relationship between shrub structure and ecological functioning in thicket, the extent of elephant effects varied between these features with distance from water. Moreover, these patterns co-varied with other confounding variables (e.g. the location of neighboring water points), which limits our ability to predict such effects in the absence of long-term data. We predict that elephant have the ability to cause severe transformation in succulent thicket habitats with abundant water supply and elevated elephant numbers. However, these piosphere effects are complex, suggesting that a more integrated understanding of elephant impacts on ecological heterogeneity may be required before water availability is used as a tool to manage impacts. We caution against the establishment of water points in novel succulent thicket habitats, and advocate a significant reduction in water provisioning at our study site, albeit with greater impacts at each water point.

(2010). Measuring the impact of indigenous herbivores: putting Hoffman et al. (2009) into a broader perspective. African Journal of Range & Forage Science: Vol. 27, No. 3, pp. 179-180.