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Over the past decade, trophy hunting in Africa has seen increased public and scientific interest. Much of that attention has come from outside of Africa, with little emphasis on local views. We circulated an online survey through international networks to explore demographic and regional differences in opinion regards support for African trophy hunting, trophy import bans, and outside funding of conservation estates supported by hunting. We received ∼5700 responses and found that location, demography, and conservation background influenced opinion. African and North American respondents showed (significantly) more support for trophy hunting than respondents from Europe or other areas, as did respondents with conservation backgrounds. Unlike North Americans, Africans supported external subsidies of wildlife areas presently funded by hunting. Many factors affected opinions on African hunting, but respondent location played a major role. Realistic policy on African trophy hunting should thus integrate African perspectives, in particular those of rural communities.

In Africa's pastoral conservation landscapes, apex predators frequently kill livestock. Retaliatory persecution such as poisoning threatens predators, but also non-target biota. Several factors influence conflict severity, including livestock husbandry, overlap in seasonal habitat use, and the degree to which livestock perceive and are able to respond to a landscape of fear. We investigated these factors by GPS-tracking 42 Tswana beef cattle (Bos taurus) from 29 herds in 2017 and six lions (Panthera leo) from different prides (May 2016–Dec. 2017) in the northern Okavango Delta, Botswana, where cattle depredation significantly impacts the livelihoods of rural agro-pastoralists. Cattle exhibited seasonal habitat selection patterns similar to wild ungulates in the region. They preferred woodland habitats, with more digestible grasses, during the wet season. During the dry season, they preferred wetland habitats with reliable forage and water availability. Cattle also preferred areas close to human settlements, but the necessity to forage in wetlands during the dry season exposed them to significant depredation risk, especially >4 km from settlements. Lions killed most cattle in wetlands during the late dry season but the intensity of recent lion presence (previous 14 days) only had a weak negative effect on cattle habitat selection patterns. Cattle used rangelands according to nutritional requirements, irrelevant of the associated predation risk, suggesting that socio-ecologically acceptable conflict solutions cannot rely on the exclusion of livestock from seasonal wetlands. Curbing depredation by lions will best be achieved by a combination of resource- and predation-cognisant seasonal herding strategies with adequate livestock protection. Understanding the ecological constraints that intensify conflict is pertinent to any livestock production landscape with predator presence. It is also a central prerequisite for future land use planning and devolution of legal, controlled resource access rights through policy. Coexistence strategies must account for the strong reliance of people, their livestock, and wildlife on shared key resources. This is particularly important in large trans-frontier conservation areas where the successful merging of biodiversity conservation and rural development is a strategic goal. Omission will foster resentment and resistance to coexistence with apex predators, particularly if livestock productivity and human livelihoods are negatively affected.

Migration of ungulates (hooved mammals) is a fundamental ecological process that promotes abundant herds, whose effects cascade up and down terrestrial food webs. Migratory ungulates provide the prey base that maintains large carnivore and scavenger populations and underpins terrestrial biodiversity (fig. S1). When ungulates move in large aggregations, their hooves, feces, and urine create conditions that facilitate distinct biotic communities. The migrations of ungulates have sustained humans for thousands of years, forming tight cultural links among Indigenous people and local communities. Yet ungulate migrations are disappearing at an alarming rate (1). Efforts by wildlife managers and conservationists are thwarted by a singular challenge: Most ungulate migrations have never been mapped in sufficient detail to guide effective conservation. Without a strategic and collaborative effort, many of the world's great migrations will continue to be truncated, severed, or lost in the coming decades. Fortunately, a combination of animal tracking datasets, historical records, and local and Indigenous knowledge can form the basis for a global atlas of migrations, designed to support conservation action and policy at local, national, and international levels.

Precise vegetation descriptions and maps are essential tools for the management of natural areas, as well as for understanding animal habitat use. The Chobe Enclave (CE), adjacent to the Chobe National Park and the Chobe Forest Reserve, forms a critical dry season range for many large herbivores. As a tool for future management and studies about wildlife habitat use and migration, this study proposed to describe the plant communities in the CE and to study their relationships with microtopography and soils. Plant species were inventoried in 82 sampling plots (40 x 20 m), covering the vegetation diversity recognised by an unsupervised classification (Landsat images, 30-m resolution). A hierarchical clustering classified the inventories in eight plant communities, mapped with a supervised classification. This study was conducted in parallel with a soil study. Soil variations and degree of flooding largely determine community composition. Floodplains along the Linyanti River and dambos (concentrating local run off from rainfall) provide reliable green forage for wildlife during the dry season. Adjacent to floodplains, riverine forests also maintain green browse and grazing well into the dry season. In drylands, vegetation is largely determined by soil texture. Forests dominated by Baikiaea plurijuga occupy the acidic, red sands in the east, while sandveld vegetation grows on deep sands in paleo-river channels. These habitats support dominant grasses, which provide important forage for grazers during the wet season. Finally, woodlands dominated by Colophospermum mopane, characterised by sodium-rich and alkaline soils, enable herbivores to meet their mineral requirements during reproduction. Conservation implications: Our soil and vegetation studies provide important insights into factors determining plant communities. Their diversity and close vicinity play a critical role in enabling herbivores to adapt to seasonal variations in forage quantity and quality. Results will enable researchers to gain insights into animal habitat seasonal use in the Chobe Enclave.

Studies investigating animal movement and habitat use are essential for wildlife management and conservation. Northern Botswana represents some of the least modified landscapes in Africa. Studying the seasonal habitat use of herbivores in these landscapes provides important baseline information with which to compare the behavioural responses of similar species occurring in anthropogenically modified landscapes. We report on the home range extent and habitat use of roan antelope (Hippotragus equinus) in a region of northern Botswana unaffected by artificial water and fences. We deployed Global Positioning System (GPS) collars on individuals in four roan antelope herds in northern Botswana, three herds in the drier northern section of Botswana and one herd in the wetter Okavango Delta. Herds in the drier northern section occupied larger home ranges (>50 km2) than did herds in the wetter Okavango Delta (

Arid and semi-arid environments have low and unpredictable rainfall patterns resulting in limited availability of surface water for wildlife. In the Central Kalahari Game Reserve (CKGR) wildlife populations have lost access to natural surface water through cordon fences, livestock and human encroachment along the access routes. Artificial waterholes have been developed in the reserve to compensate for this loss. However, there have not been any assessments of the quality of water provided for wildlife and how that may be contributing to populations declines in the CKGR. We assessed water quality from 12 artificial waterholes against both Botswana and international livestock standards for drinking. Overall the quality of water provided is poor and poses a health risk to both animals and humans. Eight out of twelve boreholes tested exceeded the maximum acceptable Total Dissolved Solids (TDS) limits while three and four boreholes have toxic levels of lead and arsenic, respectively. Thus, pumping ground water could have more negative than positive impacts on wildlife thus defeating the intended management purpose. Failure to provide water of acceptable quality is a major concern for wildlife management in the CKGR and it may underlie some wildlife declines in the reserve. These findings confirm that restriction of populations from natural water sources create complex management challenges, especially where safe and sustainable alternative sources are scarce. Restriction of access of the population to natural water sources by fences and provision of poor quality water could compromise the overall fitness of wildlife populations and contribute to their decline.

The late dry season is a period when forage resources become limited in some African savannas that can induce a strong demographic bottleneck in herbivore populations with limited access to resource heterogeneity. This study determined forage quality and quantity between wetlands and drylands habitats during the late dry season. We subjectively sampled forage characteristics in four habitat types around the distal reaches of the Tsum Tsum floodplains of the Okavango Delta during the late dry season of 2015. The habitat types were mopane and sandveld woodland far from floodplains (two major dryland habitat types), sandveld habitats that receive soil moisture inputs from adjacent floodplains (wet sandveld) and sedgeland habitat within the floodplain. Leaves collected from forage in each habitat type were oven dried, milled and analysed for total nitrogen. Data of greenness, height, biomass and protein were analysed using Kruskal-Wallis test. Forage in wet sandveld had by far the highest protein content (~16%) of all habitat types but forage height and biomass were very low, whereas sedgelands had the highest biomass of adequate-quality forage, while dryland communities had the lowest quantity and quality of forage. Thus, foraging between a higher-biomass, adequate-quality reserve resource (sedgeland) and a high-quality but low-quantity bridging resource (wet sandveld) can help to ensure a balanced protein and fibre intake during the late dry season. Our study demonstrated the importance of wetland habitats for providing green forage with sufficient biomass and protein to sustain herbivores over the late dry season.

Wildlife populations in semi-arid regions require unrestricted mobility along ecological gradients and across large landscapes to enable adaptive responses to seasonal variability and patchy resources. In the Kalahari region of Botswana, herbivore populations historically depended on seasonal access to the nutrient-rich Schwelle area in the wet season and to water from the Boteti River during drought periods. Blue wildebeest Connochaetes taurinus in the Central Kalahari Game Reserve (CKGR) have lost access to these key habitats due to fences and encroachment of livestock and humans. We deployed satellite collars onto 10 female wildebeest in the CKGR to examine seasonal movements and habitat selection in relation to the environmental conditions and fragmented ecosystem. Wildebeest favoured open, short-grass pan habitats in all seasons, probably in response to better forage quality and lower predation risk. The ability to remain in pan habitats during the dry season was a result of artificial water provision. A wildebeest herd that had no artificial water in its home range survived the dry season, whereas those wildebeest that were accustomed to water provision died when their water points failed in the dry season. Thus, water provision altered adaptive behaviour and reduced resilience of the population to the arid environment.

Rangeland management strategies must be based on robust ecological and economic concepts if they are to be effective and profitable. Thus, the aim of this paper was to examine concepts related to grazing and resting of grassland and associated effects on grassland productivity and energy flow to livestock. Our review and models demonstrate that grassland and livestock productivity is determined by lagged effects of the previous year’s grazing and by grassland maturation, which influence grass growth rates, as well as forage quality. Livestock productivity is also influenced by the scale at which livestock are able to make foraging decisions in time and space, which is restricted by increasing intensity of management (increasing rotation and declining paddock size). Finally, overstocking will override key management initiatives, such as effective recovery periods, leading to rangeland degradation. Thus, in variable climates, stocking rate should be set conservatively to allow easier adaptation of animal numbers to rainfall variability from year to year. We suggest several key concepts that can be used to design and assess grazing management strategies and make suggestions on how to implement these concepts.Keywords: forage quality, grassland productivity, Holistic Planned Grazing™, livestock performance, rotational grazing

Summary 1.Productivity and herbivory often interact to shape plant community composition and species richness with levels of production mediating the impact of herbivory. Yet, differences in herbivore traits such as size, feeding guild, and dietary requirements may result in different impacts of diverse herbivore guilds across productivity gradients. 2.We used size-selective herbivore exclosures to separate the effects of herbivory by larger herbivores, such as elephant, Burchell's zebra, and blue wildebeest from those of medium/smaller herbivores, such as impala and warthog, on herbaceous plant communities. These exclosures were established along a 10-fold productivity gradient, ranging from 90-950 g m−2 of standing plant biomass in the Kruger National Park, South Africa. 3.Exclusion of all herbivores generally increased plant species richness at low productivity but decreased richness at high productivity. Exclusion of medium/smaller herbivores (e.g. impala, warthog) showed stronger effects on plant richness, particularly loss of forbs, at higher productivity rather than at lower productivity. In contrast, exclusion of larger herbivores had stronger effects on plant richness, typically with increasing forb richness, at low rather than high productivity. 4.The change in species richness appeared linked to changes in light availability following herbivore exclusion. Strong increases in shading led to declines in species richness while more moderate increases in shading led in increases in species richness, possibly due to amelioration of heat and water stress by modest increases in shading. 5.Increasing plant dominance, which likely alters multiple mechanisms of plant interactions, was correlated with declines in plant richness following herbivore exclusion. The impact of increasing dominance on plant richness operated independent of productivity, with the exclusion of impala appearing particularly important in driving this relationship. 6.Synthesis. We show that the impact of herbivore losses on plant diversity will be strongly situation dependent and will vary with the herbivores lost (e.g. larger vs. smaller, grazers vs. browsers), plant functional type (e.g. grasses vs. forbs), and environmental context (e.g. productivity). Although larger herbivores are often emphasized for their strong impacts on community dynamics and ecosystem processes, we show that smaller, abundant herbivores can exert strong top-down control on plant communities. This article is protected by copyright. All rights reserved.

The blue wildebeest ( Connochaetes taurinus ) population in semi-arid savannah regions face intense spatial and temporal environmental variability over the annual cycle. The population in the Kalahari has lost critical seasonal ranges outside the protected areas due to human induced landscape changes. The population is faced with sparse and patchy forage availability, seasonally very high day temperatures, high predation pressure and limited availability and variable quality of water. We investigated the adaptive strategies of wildebeest in the Central Kalahari Game Reserve with a focus on how daily activity patterns respond to environmental variability in semi-arid Kalahari. The population coped with heat stress by maximising their activity in the cool hours of the day. They avoided predation pressure and loss of body condition by minimising activity at night and in dry seasons, respectively. We conclude that seasonal variations in temperature and light play a critical role in the timing of foraging activity.

As anthropogenic influences on the world’s rangelands accelerate, there is an urgency for humanity to develop a greater understanding of key drivers, and processes, underlying ecological dynamics and function, to inform improved management strategies. Browsing and grazing ungulates are important components of human-dominated and natural ecosystems, contributing to agricultural output and associated livelihoods, as well as to biodiversity and ecosystem services. A review of key concepts pertinent to the dynamics and management of browsing and grazing ungulates highlights the emergence of functional heterogeneity as a general, or unifying, theme guiding their management, whatever the scale or system. It is also clear that management of ungulate density, and the intensity of herbivory, especially in smaller-scale sedentary systems (e.g. ranches or small protected areas), is a critical determinant of functional heterogeneity. We demonstrate how the functional heterogeneity concept can be applied to the management of grazing and browsing ungulates over a range of scales and ecosystems.

On the Ground We assessed the long-term effects of continuous and rotational grazing on grass and treedynamics on adjacent ranches in the semiarid Kalahari of western Botswana. Rotationally grazed ranches had higher grass cover with more perennial grass species, higher grazing value (and capacity), and higher long-term stocking rates than their continuously grazed neighbors. Tree cover tended to be higher on continuously grazed ranches, suggesting that long-term continuous grazing reduced grass production and favored establishment of woody vegetation. Improvement in semiarid rangeland health and production is unlikely to be achieved simply by reducing stocking rates; uniform grazing and growing season recovery periods are essential. These and other case studies suggest that benefits of grazing strategies likely depend on scale and adaptive management. Future research should be at larger spatial and temporal scales.

The productivity and stability of cattle production on rangelands depends on the maintenance of a dense and productive perennial grass-dominated resource base, which is contingent on appropriate grazing and recovery periods. We investigated the effect of simulated trampling, dung inputs, frequency of defoliation in the previous growing season (grazing history), and timing of recovery periods on various grassland functional responses in two experiments in western and northwestern Botswana. A field-based clipping experiment at the individual tuft scale demonstrated that perennial grasses are most productive when rested for a full growing season, but that productivity of the highly palatable soft leaved Brachiaria nigropedata Ficalho & Hiern. decreases exponentially with increasing clipping frequency in the previous season (a lagged effect of grazing history). This species was also more productive in the next season when rested during the early than late growing season. The less palatable needle-lea...

Fire and grazing, key determinants of structure and function of savanna grasslands worldwide, have been extensively altered by humans. We used existing long-term manipulations of fire and grazing in North American and South African mesic savanna grasslands, as well as new experiments, to determine whether the impacts of fire and grazing by large herbivores differed between these systems. We found that despite a body of literature suggesting that these savanna grasslands respond uniquely to fire and grazing, their ecosystem responses (aboveground productivity) were generally similar. In contrast, plant-community responses to fire and herbivores diverged strongly between systems. The differences in plant-community responses, as well as convergence in ecosystem function, were underpinned by a common mechanism: the response of grass dominance to changing fire and grazing regimes. As a result, divergent responses of plant communities to altered fire and grazing regimes did not preclude convergence in ecosystem function.

In areas with diverse herbivore communities such as African savannas, the frequency of disturbance by fire may alter the top–down role of different herbivore species on plant community dynamics. In a seven year experiment in the Kruger National Park, South Africa, we examined the habitat use of nine common herbivore species across annually burned, triennially burned and unburned areas. We also used two types of exclosures (plus open access controls) to examine the impacts of different herbivores on plant community dynamics across fire disturbance regimes. Full exclosures excluded all herbivores > 0.5 kg (e.g. elephant, zebra, impala) while partial exclosures allowed access only to animals with shoulder heights = 0.85 m (e.g. impala, steenbok). Annual burns attracted a diverse suite of herbivores, and exclusion of larger herbivores (e.g. elephant, zebra, wildebeest) increased plant abundance. When smaller species, mainly impala, were also excluded there were declines in plant diversity, likely mediated by a decline in open space available for colonization of uncommon plant species. Unburned areas attracted the least diverse suite of herbivores, dominated by impala. Here, herbivore exclusion, especially of impala, led to strong declines in plant richness and diversity. With no fire disturbance, herbivore exclusion led to competitive exclusion via increases in plant dominance and light limitation. In contrast, on triennial burns, herbivore exclusion had no effect on plant richness or diversity, potentially due to relatively little open space for colonization across exclosure treatments but also little competitive exclusion due to the intermediate fire disturbance. Further, the diverse suite of grazers and browsers on triennial burns may have had a compensating effect of on the diversity of grasses and forbs. Ultimately, our work shows that differential disturbance regimes can result in differential consumer pressure across a landscape and result in heterogeneous patterns in top–down control of community dynamics.

Woody vegetation assessments were conducted in the burned and unburned paddocks of Tiisa Kalahari Ranch in western Botswana to determine the influence of opportunistic burning on woody species density, cover and structure in semiarid rangelands. Burning was conducted by farm management twice in one paddock in October 2005 and 2006, and once in another paddock in October 2011 to control bush encroachment. Sampling was conducted in May 2012 using 50 by 2 m transects (16 at the 2011 burn site and 18 at the 2005/2006 burn site) as paired comparisons in both burned and unburned paddocks. Tree height was 0.27 m (28%) and 0.23 m (21%) lower (P 20 stems) plants in burned paddocks (P = 0.02). Grewia flava density was 59% higher in burned paddocks (P = 0.038). At the 2005/2006 burn site both height and density of Acacia hebeclada were significantly higher in burned paddocks (65%, P = 0.045 and 56%, P = 0.037, respectively). Tarchonanthus camphoratus was only present at this site, where its height, density and cover were significantly lower in burned paddocks (P

This study aimed to establish seasonal movement and habitat selection patterns of African buffalo Syncerus caffer in relation to a detailed habitat map and according to seasonal changes in forage quality and quantity in the Savuti–Mababe–Linyanti ecosystem (Botswana). Two buffalo were collared in November 2011 and another in October 2012. All three buffalo had greater activities in the mopane–sandveld woodland mosaic during the wet season, which provided high-quality leafy grasses and ephemeral water for drinking, but moved to permanent water and reliable forage of various wetlands (swamps and floodplains) and riverine woodlands during the dry season. Wetlands had higher grass greenness, height and biomass than woodlands during the dry season. Buffalo had similar wet season concentration areas in the 2011–2012 and 2012–2013 wet seasons and similar dry season concentration areas over the 2012 and 2013 dry seasons. However, their dry season location of collaring in 2011 differed dramatically from their 2012 and 2013 dry season concentration areas, possibly because of the exceptionally high flood levels in 2011, which reduced accessibility to their usual dry season concentration areas. The study demonstrates that extremely large and heterogeneous landscapes are needed to conserve buffalo in sandy, dystrophic ecosystems with variable rainfall.Conservation implications: This study emphasises the importance of large spatial scale available for movement, which enables adaptation to changing conditions between years and seasons.

Environmental heterogeneity across savanna landscapes, including different seasonal resources at different distances to water, may play a critical role in maintaining the size and diversity of wildlife populations and the sustainability of their resource base. We investigated whether extensive landscapes with functionally diverse seasonal resources and large waterless regions can mediate the effect of herbivory on plant composition, structure and diversity. Vegetation composition, structure and richness in two different vegetation types (mopane and sandveld woodland) at three distance zones (0 km – 5 km, 10 km – 15 km and > 20 km) from the permanent water of the Okavango Delta and Linyanti Swamps were surveyed. We modelled vegetation response of the most abundant species to herbivory in relation to distance from permanent water, and included fire frequency as a covariate. Trees favoured by elephants during the dry season occurred typically as immature, pollarded populations within 5 km of permanent water sources while mature tall populations of these species were found far from water (> 10 km – 15 km). Similarly, short high-quality grazing grasses were higher in abundance within 5 km of permanent water, whereas taller high-quality perennial grasses peaked in abundance beyond 20 km from permanent water. Trends in herbaceous richness with distance from water were contingent upon vegetation type, while tree richness did not change with distance from water. Spatial refuges in waterless regions of landscapes facilitate the creation of heterogeneity of vegetation structure, composition and richness by large herds of mammalian herbivores. Therefore, the extension of herbivore dry season foraging range, for example, by the creation of artificial water points (AWP) in backcountry woodlands, could seriously undermine the resilience of landscapes to herbivory by reducing the availability of spatial refuges. Consequently, it reduces the resilience of herbivore and predator populations that depend on these spatial refuges. We strongly advise that future scientific work, and management and policy actions should be focused on the identification and sustaining of these spatial refuges in wildlife areas.Conservation implications: Management and policy actions should be focused on the identification and sustainability of spatial refuges in wildlife areas. Too many AWP in backcountry woodlands could undermine the resilience of landscapes to herbivory by reducing the proportion of landscapes beyond 15 km from permanent water.

This study classified the vegetation of the Savuti-Mababe-Linyanti ecosystem (SMLE), northern Botswana and developed a detailed map that provides a reliable habitat template of the SMLE for future wildlife habitat use studies. The major vegetation units of the SMLE were determined from satellite imagery and field visits and then mapped using Landsat 8 and RapidEye imagery and maximum likelihood classifier. These units were sampled using 40 m x 20 m (800 m²) plots in which the coverage of all plant species was estimated. Non-metric multidimensional scaling (NMS) demonstrated that plant communities were determined by gradients in soil texture or fertility and wetness. NMS 1 represented a gradient of soil texture with seven woodland communities on sandy soils (sandveld communities and Baikiaea forest) dominated by Baikiaea plurijuga in Baikiaea forest and Terminalia sericea and Philenoptera nelsii in sandveld, with various indicator species differentiating the various sandveld community types. Mopane woodland further from and riparian woodland adjacent to permanent water was common on less sandy alluvial soils. Mineral-rich, heavy clay soils in the sump of a large paleolake system support open grassland and mixed Senegalia/Vachellia (Acacia) savanna, with the mineral-rich soils supporting grasses high in minerals such as phosphorus, calcium, sodium and potassium, and thus this region is a critical wet season range for migratory zebra. Taller, high-quality grasses in the mosaic of sandveld and mopane woodland communities provide critical grazing for taller grass grazers such as buffalo, roan and sable antelope, whereas wetland communities provide reliable green forage during the dry season for a variety of herbivores, including elephant. This study has demonstrated how large-scale environmental gradients determine functional habitat heterogeneity for wildlife.Conservation implications: Our study demonstrated that the functionality of protected areas is determined by large-scale environmental gradients. Thus conservation science must aim to ensure that protected areas cover the full range of key environmental gradients in a region (soil texture and wetness in our study). Our habitat map provides a data base for wildlife habitat use studies in the region.

Rangeland management, like most disciplines of natural resource management, has been characterized by human efforts to reduce variability and increase predictability in natural systems (steady-state management often applied through a command-and-control paradigm). Examples of applications of traditional command and control in natural resource management include wildfire suppression, fences to control large ungulate movements, predator elimination programs, and watershed engineering for flood control and irrigation. Recently, a robust theoretical foundation has been developed that focuses on our understanding of the importance of variability in nature. This understanding is built upon the concept of heterogeneity, which originated from influential calls to consider spatial and temporal scaling in ecological research. Understanding rangeland ecosystems from a resilience perspective where we recognize that these systems are highly variable in space and time cannot be achieved without a focus on heterogeneity across multiple scales. We highlight the broad importance of heterogeneity to rangelands and focus more specifically on (1) animal populations and production, (2) fire behavior and management, and (3) biodiversity and ecosystem function. Rangelands are complex, dynamic, and depend on the variability that humans often attempt to control to ensure long-term productivity and ecosystem health. We present an ecological perspective that targets variation in rangeland properties—including multiple ecosystem services—as an alternative to the myopic focus on maximizing agricultural output, which may expose managers to greater risk. Globally, rangeland science indicates that heterogeneity and diversity increase stability in ecosystem properties from fine to broad spatial scales and through time.

Environmental heterogeneity across savanna landscapes, including different seasonal resources at different distances to water, may play a critical role in maintaining the size and diversity of wildlife populations and the sustainability of their resource base. We investigated whether extensive landscapes with functionally diverse seasonal resources and large waterless regions can mediate the effect of herbivory on plant composition, structure and diversity. Vegetation composition, structure and richness in two different vegetation types (mopane and sandveld woodland) at three distance zones (0 km – 5 km, 10 km – 15 km and > 20 km) from the permanent water of the Okavango Delta and Linyanti Swamps were surveyed. We modelled vegetation response of the most abundant species to herbivory in relation to distance from permanent water, and included fire frequency as a covariate. Trees favoured by elephants during the dry season occurred typically as immature, pollarded populations within 5 km of permanent water sources while mature tall populations of these species were found far from water (> 10 km – 15 km). Similarly, short high-quality grazing grasses were higher in abundance within 5 km of permanent water, whereas taller high-quality perennial grasses peaked in abundance beyond 20 km from permanent water. Trends in herbaceous richness with distance from water were contingent upon vegetation type, while tree richness did not change with distance from water. Spatial refuges in waterless regions of landscapes facilitate the creation of heterogeneity of vegetation structure, composition and richness by large herds of mammalian herbivores. Therefore, the extension of herbivore dry season foraging range, for example, by the creation of artificial water points (AWP) in backcountry woodlands, could seriously undermine the resilience of landscapes to herbivory by reducing the availability of spatial refuges. Consequently, it reduces the resilience of herbivore and predator populations that depend on these spatial refuges. We strongly advise that future scientific work, and management and policy actions should be focused on the identification and sustaining of these spatial refuges in wildlife areas.Conservation implications: Management and policy actions should be focused on the identification and sustainability of spatial refuges in wildlife areas. Too many AWP in backcountry woodlands could undermine the resilience of landscapes to herbivory by reducing the proportion of landscapes beyond 15 km from permanent water.

Herbivory and fire shape plant community structure in grass-dominated ecosystems, but these disturbance regimes are being altered around the world. To assess the consequences of such alterations, we excluded large herbivores for seven years from mesic savanna grasslands sites burned at different frequencies in North America (Konza Prairie Biological Station, Kansas, USA) and South Africa (Kruger National Park). We hypothesized that the removal of a single grass-feeding herbivore from Konza would decrease plant community richness and shift community composition due to increased dominance by grasses. Similarly, we expected grass dominance to increase at Kruger when removing large herbivores, but because large herbivores are more diverse, targeting both grasses and forbs, at this study site, the changes due to herbivore removal would be muted. After seven years of large-herbivore exclusion, richness strongly decreased and community composition changed at Konza, whereas little change was evident at Kruger. We found that this divergence in response was largely due to differences in the traits and numbers of dominant grasses between the study sites rather than the predicted differences in herbivore assemblages. Thus, the diversity of large herbivores lost may be less important in determining plant community dynamics than the functional traits of the grasses that dominate mesic, disturbance-maintained savanna grasslands.

This study aimed to determine the functional seasonal attributes for herbivores of the major habitats and landscapes of the Savuti-Mababe-Linyanti ecosystem (SMLE) of northern Botswana and how various herbivore species responded to this heterogeneity. Floodplain grasslands and dambo grasslands provided the only significant green forage and biomass during the late dry season, whereas short grasslands of the Mababe Depression provided the highest forage quality of all habitats during the wet season. The ability to provide reliable forage and drinking water in floodplain,swampand dambo grasslands attracted large concentrations of zebra and buffalo during the dry season, which was mediated by fire. Large concentrations of zebra were observed in mineral-rich grasslands of the Mababe Depression during the wet season, whereas buffalo were not observed in these open grassland landscapes in this season. Other herbivore species appeared to use the same landscapes year-round where lechwe were observed mainly in floo...

The interaction, both above and belowground, between tree saplings and the surrounding grass sward is dependent on solar radiation, temperature, rainfall, soil depth, tree species and sward composition. These factors, as well as level of sward defoliation, influence whether the system will remain as savanna or move towards a woodland or grassland state. The effects of above- and belowground competition between grasses and two Acacia species and the effects of soil depth on these interactions were examined by planting A. karroo and A. nilotica seedlings into a natural sward on three different soil depths. Three aboveground treatments: full shading, reduced shading by tying back the neighboring grasses and reduced shading by clipping, and two belowground treatments: full and no belowground competition, were used. Plant size increased with increasing soil depth, while belowground competitive intensity was unaffected. Removing belowground competition increased sapling biomass by half (P < 0.05) on all soil depths. By contrast, reduced shading had little effect at all soil depths, whereas sward clipping increased sapling biomass (47%) on shallow soils only (P = 0.027), indicating that encroachment on shallow soils may result from factors that decrease root vigor of the surrounding grasses rather than light competition. Irrespective of soil depth, root competition appeared to be the major factor influencing sapling growth rates, thus grazing management practices that reduce grass root productivity are expected to result in woody encroachment.

Question: Doesfirefrequency affect mesic grassland plant community structure and composition similarly in North America and South Africa?

Knowledge of the success or otherwise of conservation interventions is often locked within localised networks, resulting in mistakes being replicated unnecessarily. The savannahs of eastern and southern Africa are home to spectacular ecosystems with similar ecology yet markedly different conservation practices between the two regions. Pressures on east African ecosystems are rising in ways similar to those of southern Africa several decades ago. Conservation practitioners and researchers from southern and eastern Africa came together for a 5-day workshop to identify by consensus a short list of 10 most important lessons for management of savannah habitats learnt from the southern experience. The lessons identified concerned (1) protected area design, (2) community relationships, (3) buffer zones, (4) the importance of migrations and corridors, (5) river catchment management, (6) law enforcement, (7) invasive plants, (8) road planning, (9) loss of heterogeneity, and (10) communication between researchers and practitioners. The lessons learnt from southern Africa can prevent many mistakes being made in east African protected area management, providing they are implemented on the ground.

We made use of pot experiments and soil mineralisation assays to test the effect of temperature on the soil nitrogen (N) economy of the Drakensberg Alpine Centre (‘mountain site’). The approach was enhanced by the inclusion of a contrasting warm, subtropical environment on the east coast of southern Africa (‘coast site’) which presented an opportunity to test plant growth in mountain soil outside of the mountain site's natural climatic envelope. This study was further augmented by two greenhouse experiments that helped isolate the factors responsible for the growth responses in the experiments above. Plant morphology, plant nutrients and soil nutrients were used as the basis for comparing treatment effects. The primary pot experiment showed that plant growth was uniform in the mountain site regardless of whether the test species was grown in intrinsically N-rich mountain soil or intrinsically N-poor coast soil. However, we noted significant growth differences at the coast site using the aforementioned soil nutrient regimes. In terms of the soil mineralisation assay, coast soil, derived from intrinsically N-poor sandstone, predictably mineralised little soil inorganic N at the mean spring temperature of 19°C. However against expectations, the intrinsically N-rich mountain soil mineralised

We conducted herbaceous and woody vegetation surveys across Botswana’s southern Okavango Buffalo Fence, which separates wildlife management from tribal grazing areas, to determine whether the restriction of herbivore movement by fencing has influenced vegetation composition, diversity and structure. We sampled herbaceous and woody vegetation at twenty paired sites every 2 km along the fence. For the herbaceous layer, ten 0.25 m 2 quadrats were laid every 10 m perpendicular to the fence; while for the woody vegetation, variable quadrat plots were used. Paired t-tests were run. Results show little difference in forb or grass composition between the two sides. However, the cover and diversity of many woody species were greatly reduced across most height classes on the wildlife management side. Overall woody cover on the wildlife side of the fence was nearly half that of the tribal grazing side (t = 2.83, P = 0.011, df = 19), while overall wood diversity was also significantly less on the wildlife side (t = 3.29, P = 0.004, df = 19). We conclude that the concentration of wildlife due to the fence, while improving habitat for some herbivore species, is having a detrimental effect on plant diversity in general.

The structure and composition of savanna vegetation is influenced by resource availability and disturbance. Grasses, a major component of savanna systems, influence the tree-grass balance by competing with trees for light, water and soil nutrients as well as providing fuel for fires. Overgrazing, and the ensuing decreased grass competition and fire effects resulting from diminished grass vigor and cover, are thought to be major drivers of bush encroachment. To investigate impacts of competition from grass on saplings of Acacia karroo Hayne. and Acacia nilotica (L.). Willd. ex. Del. under high and low soil fertility, six grass species, Aristida junciformis (Trin & Rupr.), Eragrostis capensis (Thunb.) Trin., Hyparrhenia hirta Stapf., Panicum maximum Jacq., Sporobolus africanus (Poir.) Robyns & Tournay and Themeda triandra Forssk., were planted in pots with a tree sapling as the central test species. The major competitive effects experienced by tree saplings were dependent on nutrient level and the identity of the competing grass species (P < 0.001). Aboveground A. karroo was more strongly affected by grass competition under high nutrient conditions, whereas an increase in nutrient level had little effect on the competition between A. nilotica and the grasses (P < 0.001). Acacia karroo was also strongly affected by grass competition belowground; however, the opposite trend was observed for A. nilotica (P < 0.001). Eragrostis capensis was one of the most competitive grass species, reducing sapling aboveground biomass by 85% and 65% under high and low nutrient conditions, respectively, and sapling belowground biomass by 71% on average. Increasing nutrient availability resulted in an increase in competition exerted on A. karroo by all grasses but little to no change for A. nilotica. Changes in savanna composition and structure are thus likely to be influenced by grass species composition and soil nutrient status.

Summary 1. African savannas are complex socio-ecological systems with diverse wild and domestic herbivore assemblages, which adapt spatially to intra- and interannual variation in forage quantity and quality, predation and disease risks. 2. As African savannas become increasingly fragmented by growing human populations and their associated ecological impacts, adaptive foraging options for wild and domestic herbivore populations are correspondingly limited, resulting in declining wildlife populations and impoverished pastoral societies. In addition, competition for grazing by expanding domestic herbivore populations threatens the viability of wild herbivore populations occupying similar grazing niches. 3. Conservation initiatives are further impacted by conflicts between wildlife and local communities of people who often receive little benefit from adjacent protected areas, creating conflict between the livelihood-orientated goals of communities and the conservation-oriented goals of the international community and those with vested interests in wildlife. Conservation strategies facilitating the alignment of these opposing goals of communities and conservationists are needed. 4. Synthesis and applications. Key to understanding facilitative and competitive interactions between wild and domestic herbivores are the concepts of niche differentiation and functional resource heterogeneity. Uncontrolled incursions of burgeoning domestic herbivore populations into protected areas (PAs) threaten the conservation of wild herbivore biodiversity. However, domestic herbivores can be managed to minimize competition with wild herbivores and to enhance habitat by maximizing grassland structural heterogeneity (greater adaptive foraging options), creation of nutrient hotspots in the landscape and facilitation of high-quality grazing. Ecosystem service benefits to communities through controlled access to grazing resources in PAs, associated with appropriate disease management, can provide a conservation payment to promote communities’ support of conservation of key wildlife migratory ranges and corridors outside PAs.

Aims mesic grasslands have a long evolutionary history of grazing by large herbivores and as a consequence, grassland species have numerous adaptations allowing them to respond favourably to grazing. although empirical evidence has been equivocal, theory predicts that such adaptations combined with alterations in resources can lead to grazing-induced overcompensation in aboveground net primary production (aNPP; grazed aNPP > ungrazed aNPP) under certain conditions. We tested two specific predictions from theory. First, overcompensation is more likely to occur in annually burned grasslands because limiting nutrients that would be lost with frequent fires are recycled through grazers and stimulate aNPP. second, overcompensation of biomass lost to grazers is more likely to occur in unburned sites where grazing has the greatest effect on increasing light availability through alterations in canopy structure. Methods

Most of the world's rangelands are subject to large spatial and temporal variation in forage quantity and quality, which can have severe consequences for the stability and profitability of livestock production. Adaptive foraging movements between functional seasonal resources can help to ameliorate the destabilizing effects on herbivore body stores of spatial and temporal variability of forage quantity and quality. Functional dry-season habitats (key resources) provide sufficient nutrients and energy to minimize reliance on body stores and are critical for maintaining population stability by buffering the effects of drought. Functional wet-season habitats dominated by short, nutritious grasses facilitate optimal intake of nutrients and energy for lactating females, for optimal calf growth rates and for building body stores. Adaptive foraging responses to high-quality focal patches induced by rainfall and disturbance further facilitate intake of nutrients and energy. In addition, focused grazing impact in high-quality patches helps to prevent grassland maturing and losing quality. In this regard, the design of many rotational grazing systems is conceptually flawed because of their inflexible movement of livestock that does not allow adaptation to spatial and temporal variability in forage quantity and quality or sufficient duration of stay in paddocks for livestock to benefit from self facilitation of grazing. Similarly the fixed intraseasonal resting periods of most rotational grazing systems might not coincide with the key pulses of nitrogen mineralization and rainfall in the growing season, which can reduce their efficiency in providing a functional recovery period for grazed grasses. This might explain why complex rotational grazing systems on average have not out-performed continuous grazing systems. It follows, therefore, that ranchers need to adopt flexible grazing management practices that allow adaptation to spatial and temporal variability in forage quantity and quality, allow facilitation of grazing (season-long grazing), and allow more effective recovery periods (season-long resting).

Question: Following the framework of Suding et al. (2003), we examined whether morphological traits (organismal response), tolerance and competitive effect (specific process response) were associated with grass dominance (abundance response) on burning, mowing, fertilization and soil depth gradients in KwaZulu-Natal (KZN), South Africa. Location: University of KwaZulu-Natal, Pietermaritzburg, South Africa. Methods: Using several pot experiments involving 29 grass species in total, we determined the vegetative traits, competitive effect and response, and tolerance to shading for grasses common in closed, tufted mesic grassland in KZN. Results: The primary axis of grass–trait variation was most strongly related to a negative correlation (trade-off) between growth rate and specific leaf area (SLA), with broad-leaved, rapidly-growing grasses (high SLA) occupying one extreme and narrow-leaved, slow-growing grasses (low SLA) the other extreme of the first principal component. The low SLA, slow-growth strategy was found to be a relatively general strategy among grasses dominant in undisturbed, high litter grassland, as well as those adapted to moisture-stressed habitats. In contrast, grasses dominant in highly productive habitats with some form of disturbance, e.g. mowing, had a broad-leaved, rapid-growth strategy. Intermediate combinations of the SLA–growth rate trade-off were common among grasses dominant under other combinations of disturbance and soil resource availability. Conclusions: Distinct patterns of organismal (SLA, growth rate) and specific process (competitive effect and response, as well as tolerance of shading) responses appeared to be associated with grasses dominant on gradients of burning, mowing, fertilization and soil depth. These organismal and specific process responses were similar to those for North American and European grasses dominant under the same environmental influences, suggesting that some general trait–environment patterns exist at an inter-continental scale. This general trait–environment relationship appears to be driven by functional adaptive selection along the SLA–environment continuum and its unavoidable trade-off with growth rate.

National Research Foundation (NRF), Paul G. Allen Family Foundation, Wilderness Safaris, Wilderness Wildlife Trust, Komanis Foundation and Elephants Without Borders.

Ungulate populations in African conservation areas (CAs) are in widespread decline, which can largely be attributed to a lack of functionality of the area encompassed by the CAs themselves. We present evidence from a wide range of African CAs showing that they do not encompass both the functional wet- and dry-season resources that ungulates traditionally migrated between. Before human populations and economic development had grown to levels where they interfered with migrations outside the CAs, ungulates were able to make use of their traditional seasonal resources but this is becoming increasingly difficult and we are now seeing the effects of this restriction of movement on ungulate population numbers. New innovative strategies are required for the conservation of African wildlife. An urgent Africa-wide survey is needed to establish past and present functional resources in and around CAs and to prioritize conservation regions that are most functional. In addition, innovative attempts need to be made to reconsolidate functional seasonal resources within revised expanded protected areas. Resume Les populations d’ongules dans les aires de conservation africaines (AC) sont largement en declin, ce que l’on peut en grande partie attribuer au manque de fonctionnalite de la superficie englobee par les AC elles-memes. Nous presentons des preuves tirees d’une large gamme d’AC africaines qui montrent qu’elles ne comprennent pas l’ensemble des ressources fonctionnelles de saison des pluies et de saison seche entre lesquelles les ongules ont l’habitude de migrer. Avant que les populations humaines et le developpement economique n’aient atteint des niveaux ou ils interferent avec les migrations qui se font en dehors des AC, les ongules etaient a meme d’utiliser leurs ressources saisonnieres traditionnelles, mais ceci est devenu de plus en plus difficile, et nous voyons desormais les effets de cette restriction des deplacements sur les chiffres des populations d’ongules. Il est urgent de realiser une etude a l’echelle du continent pour etablir quelles sont les ressources fonctionnelles passees et presentes dans et autour des AC et pour prioriser les regions de conservation qui sont les plus fonctionnelles. De plus, il faut innover pour consolider les ressources fonctionnelles saisonnieres au sein d’aires protegees revisees et elargies.

Patterns and controls of annual aboveground net primary productivity (ANPP) are fundamental metrics of ecosystem functioning. It is generally assumed, but rarely tested, that determinants of ANPP in one region within a biome will operate similarly throughout that biome, as long as physiognomy and climate are broadly consistent. We tested this assumption by quantifying ANPP responses to fire, grazing history, and nitrogen (N) addition in North American (NA) and South African (SA) savanna grasslands. We found that total ANPP responded in generally consistent ways to fire, grazing history, and N addition on both continents. Annual fire in both NA and SA consistently stimulated total ANPP (28–100%) relative to unburned treatments at sites with deep soils, and had no effect on ANPP in sites with shallow soils. Fire did not affect total ANPP in sites with a recent history of grazing, regardless of whether a single or a diverse suite of large herbivores was present. N addition interacted strongly and consistently with fire regime in both NA and SA. In annually burned sites that were not grazed, total ANPP was stimulated by N addition (29–39%), but there was no effect of N fertilization in the absence of fire. In contrast, responses in forb ANPP to fire and grazing were somewhat divergent across this biome. Annual fire in NA reduced forb ANPP, whereas grazing increased forb ANPP, but neither response was evident in SA. Thus, despite a consistent response in total ANPP, divergent responses in forb ANPP suggest that other aspects of community structure and ecosystem functioning differ in important ways between these mesic savanna grasslands.

Question: What is the long-term influence of nutrient availability, productivity and soil pH on grassland community organization? Location: Ukulinga research farm, KwaZulu-Natal, South Africa. Methods: The influence of fertilization on soil pH, nitrogen (N) and phosphorus (P) on variation in plant traits, community composition and species richness were examined in a 50-year grassland fertilization experiment. Results: Averaged over 30 years, above-ground net primary production (ANPP) was 337, 428 and 518 g.m−2 in sites not fertilized, fertilized with N, and fertilized with N plus P respectively. ANPP depended directly on N-fertilization but not on P-fertilization or liming, and responded positively to the interaction of N (first limiting nutrient) and P (second limiting nutrient). Short narrow-leaved grass species – Themeda triandra, Tristachya leucothrix and Setaria nigrirostris – dominated sites of lowest ANPP where N was limiting (unfertilized, P-fertilized or limed sites). A tall narrow-leave...

Book Title: Grasses and Grazers of Botswana and the Surrounding Savanna Book Author: Veronica Roodt 2015, Struik Publishers, PO Box 1144, Cape Town 8001, South Africa. 344 pages, softcover. ISBN 978-1-775-84115-9. Price R290.00

Large herbivore grazing is a widespread disturbance in mesic savanna grasslands which increases herbaceous plant community richness and diversity. However, humans are modifying the impacts of grazing on these ecosystems by removing grazers. A more general understanding of how grazer loss will impact these ecosystems is hampered by differences in the diversity of large herbivore assemblages among savanna grasslands, which can affect the way that grazing influences plant communities. To avoid this we used two unique enclosures each containing a single, functionally similar large herbivore species. Specifically, we studied a bison (Bos bison) enclosure at Konza Prairie Biological Station, USA and an African buffalo (Syncerus caffer) enclosure in Kruger National Park, South Africa. Within these enclosures we erected exclosures in annually burned and unburned sites to determine how grazer loss would impact herbaceous plant communities, while controlling for potential fire-grazing interactions. At both sites, removal of the only grazer decreased grass and forb richness, evenness and diversity, over time. However, in Kruger these changes only occurred with burning. At both sites, changes in plant communities were driven by increased dominance with herbivore exclusion. At Konza, this was caused by increased abundance of one grass species, Andropogon gerardii, while at Kruger, three grasses, Themeda triandra, Panicum coloratum, and Digitaria eriantha increased in abundance.

Mesic grasslands in North America and South Africa share many structural attributes, but less is known of their functional similarities. We assessed the control of a key ecosystem process, aboveground net primary production (ANPP), by interannual variation in precipitation amount and pattern via analysis of data sets (15- and 24-year periods) from long-term research programs on each continent. Both sites were dominated by C(4) grasses and had similar growing season climates; thus, we expected convergence in precipitation-ANPP relationships. Lack of convergence, however, would support an alternative hypothesis-that differences in evolutionary history and purportedly greater climatic variability in South Africa fundamentally alter the functioning of southern versus northern hemisphere grasslands. Neither mean annual precipitation nor mean ANPP differed between the South African and North American sites (838 vs. 857 mm/year, 423.5 vs. 461.4 g/m(2) respectively) and growing season precipitation-ANPP relationships were similar. Despite overall convergence, there were differences between sites in how the seasonal timing of precipitation affected ANPP. In particular, interannual variability in precipitation that fell during the first half of the growing season strongly affected annual ANPP in South Africa (P0.01), but was not related to ANPP in North America (P = 0.098). Both sites were affected similarly by late season precipitation. Divergence in the seasonal course of available soil moisture (chronically low in the winter and early spring in the South African site vs. high in the North American site) is proposed as a key contingent factor explaining differential sensitivity in ANPP to early season precipitation in these two grasslands. These long-term data sets provided no support for greater rainfall, temperature or ANPP variability in the South African versus the North American site. However, greater sensitivity of ANPP to early season precipitation in the South African grassland suggests that future patterns of productivity may be more responsive to seasonal changes in climate compared with the North American site.

2010, Wiley-Blackwell, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK Softcover, 448 pp ISBN 9781405177856. Price £45.00/€54.00