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Summary: Strong paleoclimatic change and few Late Quaternary megafauna extinctions make mainland Africa unique among continents. Here, we hypothesize that, compared with elsewhere, these conditions created the ecological opportunity for the macroevolution and geographic distribution of large fruits.We assembled global phylogenetic, distribution and fruit size data for palms (Arecaceae), a pantropical, vertebrate‐dispersed family with > 2600 species, and integrated these with data on extinction‐driven body size reduction in mammalian frugivore assemblages since the Late Quaternary. We applied evolutionary trait, linear and null models to identify the selective pressures that have shaped fruit sizes.We show that African palm lineages have evolved towards larger fruit sizes and exhibited faster trait evolutionary rates than lineages elsewhere. Furthermore, the global distribution of the largest palm fruits across species assemblages was explained by occurrence in Africa, especially under low canopies, and extant megafauna, but not by mammalian downsizing. These patterns strongly deviated from expectations under a null model of stochastic (Brownian motion) evolution.Our results suggest that Africa provided a distinct evolutionary arena for palm fruit size evolution. We argue that megafaunal abundance and the expansion of savanna habitat since the Miocene provided selective advantages for the persistence of African plants with large fruits. This article is part of the Special Collection 'Global plant diversity and distribution'. See https://www.newphytologist.org/global-plant-diversity for more details. [ABSTRACT FROM AUTHOR]

Megaherbivores perform vital ecosystem engineering roles, and have their last remaining stronghold in Africa. Of Africa's remaining megaherbivores, the common hippopotamus (Hippopotamus amphibius) has received the least scientific and conservation attention, despite how influential their ecosystem engineering activities appear to be. Given the potentially crucial ecosystem engineering influence of hippos, as well as mounting conservation concerns threatening their long‐term persistence, a review of the evidence for hippos being ecosystem engineers, and the effects of their engineering, is both timely and necessary. In this review, we assess, (i) aspects of hippo biology that underlie their unique ecosystem engineering potential; (ii) evaluate hippo ecological impacts in terrestrial and aquatic environments; (iii) compare the ecosystem engineering influence of hippos to other extant African megaherbivores; (iv) evaluate factors most critical to hippo conservation and ecosystem engineering; and (v) highlight future research directions and challenges that may yield new insights into the ecological role of hippos, and of megaherbivores more broadly. We find that a variety of key life‐history traits determine the hippo's unique influence, including their semi‐aquatic lifestyle, large body size, specialised gut anatomy, muzzle structure, small and partially webbed feet, and highly gregarious nature. On land, hippos create grazing lawns that contain distinct plant communities and alter fire spatial extent, which shapes woody plant demographics and might assist in maintaining fire‐sensitive riverine vegetation. In water, hippos deposit nutrient‐rich dung, stimulating aquatic food chains and altering water chemistry and quality, impacting a host of different organisms. Hippo trampling and wallowing alters geomorphological processes, widening riverbanks, creating new river channels, and forming gullies along well‐utilised hippo paths. Taken together, we propose that these myriad impacts combine to make hippos Africa's most influential megaherbivore, specifically because of the high diversity and intensity of their ecological impacts compared with other megaherbivores, and because of their unique capacity to transfer nutrients across ecosystem boundaries, enriching both terrestrial and aquatic ecosystems. Nonetheless, water pollution and extraction for agriculture and industry, erratic rainfall patterns and human–hippo conflict, threaten hippo ecosystem engineering and persistence. Therefore, we encourage greater consideration of the unique role of hippos as ecosystem engineers when considering the functional importance of megafauna in African ecosystems, and increased attention to declining hippo habitat and populations, which if unchecked could change the way in which many African ecosystems function. [ABSTRACT FROM AUTHOR]

Ecotourism helps sustain protected areas (PAs) that in turn conserve Africa's declining fauna. Identifying ecotourist preferences and which species and landscapes benefit from ecotourism could therefore support African biodiversity conservation efforts. Due to historic associations with trophy hunting and subsequent ecotourism marketing efforts, ecotourist preferences have been thought to traditionally center around the 'Big Five': elephant, lion, buffalo, leopard, and rhinoceros. But these preferences may be evolving. Here, we ask two questions, one about the drivers and one about the consequences of ecotourism: (1) Which species and landscapes do ecotourists most prefer based on realized visitation data? And (2), differently, which species and landscapes benefit most from ecotourism? We gathered data on average annual tourist visits, the occurrence of nine mammals, bird species richness, forest cover, national wealth, local human population and accessibility for 164 Sub‐Saharan African PAs. To address our first question, we used a Bayesian multivariable model to identify whether bird and megafaunal diversity explain visits to PAs while controlling for other factors. To address our second question, we used Bayesian univariate models to analyze the relationships between park visitation and each species/landscape. We found that tourist preferences extend beyond the Big Five to include bird diversity. We also observed that ecotourism may be well suited to conserve bird diversity, lion, cheetah, black and white rhinoceros, African wild dog and giraffe species. Collectively, our results may help inform how to leverage ecotourism to conserve African fauna. [ABSTRACT FROM AUTHOR]

Filling the global biodiversity financing gap will require significant investments from financial markets, which demand credible valuations of ecosystem services and natural capital. However, current valuation approaches discourage investment in conservation because their results cannot be verified using market-determined prices. Here, we bridge the gap between finance and conservation by valuing only wild animals' carbon services for which market prices exist. By projecting the future path of carbon service production using a spatially explicit demographic model, we place a credible value on the carbon capture services produced by African forest elephants. If elephants were protected, their services would be worth $20.8 billion ($10.3 to $29.7 billion) and $25.9 billion ($12.8 to $37.6 billion) for the next 10 and 30 y, respectively, and could finance anti-poaching and conservation programs. Elephant population growth would generate a carbon sink of 109 MtC (64 to 153) across tropical Africa in the next 30 y. Avoided elephant extinction would also prevent the loss of 93 MtC (46 to 130), which is the contribution of the remaining populations. Uncertainties in our projections are controlled mainly by forest regeneration rates and poaching intensity, which indicate that conservation can actively reduce uncertainty for increased financial and biodiversity benefits. Our methodology can also place lower bounds on the social cost of nature degradation. Poaching would result in $2 to $7 billion of lost carbon services within the next 10 to 30 y, suggesting that the benefits of protecting elephants far outweigh the costs. Our methodology enables the integration of animal services into global financial markets with major implications for conservation, local socioeconomies, and conservation. [ABSTRACT FROM AUTHOR]

Fire and herbivory interact to alter ecosystems and carbon cycling. In savannas, herbivores can reduce fire activity by removing grass biomass, but the size of these effects and what regulates them remain uncertain. To examine grazing effects on fuels and fire regimes across African savannas, we combined data from herbivore exclosure experiments with remotely sensed data on fire activity and herbivore density. We show that, broadly across African savannas, grazing herbivores substantially reduce both herbaceous biomass and fire activity. The size of these effects was strongly associated with grazing herbivore densities, and surprisingly, was mostly consistent across different environments. A one-zebra increase in herbivore biomass density (~100 kg/km 2 of metabolic biomass) resulted in a ~53 kg/ha reduction in standing herbaceous biomass and a ~0.43 percentage point reduction in burned area. Our results indicate that fire models can be improved by incorporating grazing effects on grass biomass., (© 2024 John Wiley & Sons Ltd. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Knowledge of and the technologies and resources applied to the ex situ care for wildlife have improved greatly in recent years. This has resulted in numerous successes bringing back populations from the brink of extinction by the reintroduction or restoration of animals from conservation breeding programmes. Controlled breeding of wildlife by humans is discussed controversially in society and in scientific circles and it faces a number of significant challenges. When natural breeding fails, Assisted Reproduction Technologies (ART) have been postulated to increase reproductive output and maintain genetic diversity. Furthermore, technical advances have improved the potential for successful collection and cryopreservation of gametes and embryos in many wildlife species. With the aim of creating a better understanding of why ex situ and in situ conservation of threatened species must complement each other, and under which circumstances ART provide additional tools in the rescue of a threatened population, we elucidate the current situation here by using as examples three different megavertebrate families: elephantidae, rhinoceridae and giraffidae. These mammal families consist of charismatic species, and most of their members are currently facing dramatic declines in population numbers. On the basis of these and other examples, we highlight the importance of captive zoo and other managed wildlife populations for species survival in a human dominated world. Without the possibility to study reproductive physiology in trained or habituated captive individuals, major advances made in wildlife ART during the past 20 years would not have been possible. This paper reviews the benefits and future challenges of large mammal conservation breeding and examines the role of assisted reproduction in such efforts. • Due to human encroachment, wildlife will more and more require managment in reserves, especially in Africa. • Conservation breeding programmes will play a decisive role for megavertebrate species survival. • For an integrated conservation approach, captive and free roaming individuals of a species need to be managed as one population. • Assisted reproduction techniques are key to connnect isolated populations and increase genetic diversity in and ex situ. [ABSTRACT FROM AUTHOR]

Large specialized fruit (megafaunal fruit) have evolved alongside megaherbivores to take advantage of their unparalleled seed dispersal service. Megaherbivores were widespread and abundant in the Pleistocene but due to multiple extinction events have been extirpated from all continents except Africa and small pockets of South East Asia. In Africa, we are in the unique position of being able to study megafaunal fruits where there are still areas with a largely intact megaherbivore community. The megafaunal fruits of the African forests have been examined but those of the African savannas have been largely overlooked. We use an operational definition of megafaunal fruit developed in the Neotropics to identify megafaunal fruit in the South African tree flora. Thirty-one species were identified as megafaunal fruit-bearers, representing only 3% of the tree flora. Megafaunal tree species are well represented in the families Mimosoideae, Arecaceae, Strychnaceae and Caesalpinoideae. We explored the factors underlying the distribution of these megafaunal tree species. We found that the historical distribution of megaherbivores in South Africa does not explain the distribution of these fruit. Megaherbivores have historically been found throughout South Africa while megafaunal fruit tree species occur almost exclusively in the northern tropical reaches of the country. Abiotic factors such as precipitation and temperature appear to best explain the distribution of megafaunal fruit species in the region. We conclude that megafaunal fruit are a tropical phenomenon and their tropical origins now limit their distribution. [ABSTRACT FROM AUTHOR]

The transition of hominins to a largely meat-based diet ∼1.8 million years ago led to the exploitation of other mammals for food and resources. As hominins, particularly archaic and modern humans, became increasingly abundant and dispersed across the globe, a temporally and spatially transgressive extinction of large-bodied mammals followed; the degree of selectivity was unprecedented in the Cenozoic fossil record. Today, most remaining large-bodied mammal species are confined to Africa, where they co-evolved with hominins. Here, using a comprehensive global dataset of mammal distribution, life history and ecology, we examine the consequences of 'body size downgrading' of mammals over the late Quaternary on fundamental macroecological patterns. Specifically, we examine changes in species diversity, global and continental body size distributions, allometric scaling of geographic range size with body mass, and the scaling of maximum body size with area. Moreover, we project these patterns toward a potential future scenario in which all mammals currently listed as vulnerable on the IUCN's Red List are extirpated. Our analysis demonstrates that anthropogenic impact on earth systems predates the terminal Pleistocene and has grown as populations increased and humans have become more widespread. Moreover, owing to the disproportionate influence on ecosystem structure and function of megafauna, past and present body size downgrading has reshaped Earth's biosphere. Thus, macroecological studies based only on modern species yield distorted results, which are not representative of the patterns present for most of mammal evolution. Our review supports the concept of benchmarking the 'Anthropocene' with the earliest activities of Homo sapiens. • For most of the Cenozoic mammal extinction was not size-biased, this changed in the late Quaternary. • Late Quaternary extinctions were temporally and spatially coincident with hominin migration. • Extinctions have led to much loss of phylogenetic and functional diversity. • The loss of the largest mammals leds to changes in the continental body size distribution. • Range fragmentation and constriction have influenced the largest mammals disproportionately. [ABSTRACT FROM AUTHOR]

This review explores what past environmental change in Africa-and African people's response to it-can teach us about how to cope with life in the Anthropocene. Organized around four drivers of change-climate; agriculture and pastoralism; megafauna; and imperialism, colonialism, and capitalism (ICC)-our review zooms in on key regions and debates, including desertification; rangeland degradation; megafauna loss; and land grabbing. Multiscale climate change is a recurring theme in the continent's history, interacting with increasingly intense human activities from several million years onward, leading to oscillating, contingent environmental changes and societally adaptive responses. With high levels of poverty, fast population growth, and potentially dramatic impacts expected from future climate change, Africa is emblematic of the kinds of social and ecological precariousness many fear will characterize the future globally. African people's innovation and adaptation to contingency may place them among the avant-garde with respect to thinking about Anthropocene conditions, strategies, and possibilities. [ABSTRACT FROM AUTHOR]

Positive indirect effects of consumers on their resources can stabilize food webs by preventing overexploitation, but the coupling of trophic and non-trophic interactions remains poorly integrated into our understanding of community dynamics. Elephants engineer African savanna ecosystems by toppling trees and breaking branches, and although their negative effects on trees are well documented, their effects on small-statured plants remain poorly understood. Using data on 117 understory plant taxa collected over 7 yr within 36 1-ha experimental plots in a semi-arid Kenyan savanna, we measured the strength and direction of elephant impacts on understory vegetation. We found that elephants had neutral effects on most (83-89%) species, with a similar frequency of positive and negative responses among the remainder. Overall, estimated understory biomass was 5-14% greater in the presence of elephants across a range of rainfall levels. Whereas direct consumption likely accounts for the negative effects, positive effects are presumably indirect. We hypothesized that elephants create associational refuges for understory plants by damaging tree canopies in ways that physically inhibit feeding by other large herbivores. As predicted, understory biomass and species richness beneath elephant-damaged trees were 55% and 21% greater, respectively, than under undamaged trees. Experimentally simulated elephant damage increased understory biomass by 37% and species richness by 49% after 1 yr. Conversely, experimentally removing elephant damaged branches decreased understory biomass by 39% and richness by 30% relative to sham-manipulated trees. Camera-trap surveys revealed that elephant damage reduced the frequency of herbivory by 71%, whereas we detected no significant effect of damage on temperature, light, or soil moisture. We conclude that elephants locally facilitate understory plants by creating refuges from herbivory, which countervails the direct negative effects of consumption and enhances larger-scale biomass and diversity by promoting the persistence of rare and palatable species. Our results offer a counterpoint to concerns about the deleterious impacts of elephant 'overpopulation' that should be considered in debates over wildlife management in African protected areas: understory species comprise the bulk of savanna plant biodiversity, and their responses to elephants are buffered by the interplay of opposing consumptive and non-consumptive interactions. [ABSTRACT FROM AUTHOR]

Abstract: Understanding the cause of late Quaternary mammal extinctions is the subject of intense debate spanning the fields of archeology and paleontology. In the global context, the losses on continental Africa have received little attention and are poorly understood. This study aims to inspire new discussion of African extinctions through a review of the extinct species and the chronology and possible causes of those extinctions. There are at least 24 large mammal (>5kg) species known to have disappeared from continental Africa during the late Pleistocene or Holocene, indicating a much greater taxonomic breadth than previously recognized. Among the better sampled taxa, these losses are restricted to the terminal Pleistocene and early Holocene, between 13,000 and 6000yrs ago. The African extinctions preferentially affected species that are grazers or prefer grasslands. Where good terrestrial paleoenvironmental records are present, extinctions are associated with changes in the availability, productivity, or structure of grassland habitats, suggesting that environmental changes played a decisive role in the losses. In the broader evolutionary context, these extinctions represent recent examples of selective taxonomic winnowing characterized by the loss of grassland specialists and the establishment of large mammal communities composed of more ecologically flexible taxa over the last million years. There is little reason to believe that humans played an important role in African extinctions. [Copyright &y& Elsevier]

Abstract: The majority of terrestrial ecosystems outside Africa have lost megafaunal vertebrates (>44kg) since the Middle Pleistocene and most of these extinctions can be attributed to human influence. This review assesses the likely impacts of prehistoric megafaunal extinctions in the lowland tropics and discusses the implications for contemporary conservation management. The most likely impacts include: the coextinction of parasites, a reduction in environmental heterogeneity, the release of competitors and prey (including plants), and a loss of quality and quantity in seed dispersal services. This, however, is based largely on arguments by analogy with the surviving megafauna, since the impacts of megafaunal losses are compounded in the paleoenvironmental record with changes in climate and other human impacts. Suggested conservation responses include: prioritizing the conservation of the surviving megafaunal species and reintroducing them, where possible, into parts of their former ranges; reversible experiments with the introduction of taxon substitutes outside their natural ranges; and special conservation attention to megafaunal-dependent orphans and anachronisms. [Copyright &y& Elsevier]

Africa is unique among the continents in having maintained an extraordinarily diverse and prolific megafauna spanning the Pleistocene-Holocene epochs. Little is known about the historical dynamics of this community and even less about the reasons for its unique persistence to modern times. We sequenced complete mitochondrial genomes from 43 Cape buffalo ( Syncerus caffer caffer) to infer the demographic history of this large mammal. A combination of Bayesian skyline plots, simulations and Approximate Bayesian Computation (ABC) were used to distinguish population size dynamics from the confounding effect of population structure and identify the most probable demographic scenario. Our analyses revealed a late Pleistocene expansion phase concurrent with the human expansion between 80 000 and 10 000 years ago, refuting an adverse ecological effect of Palaeolithic humans on this quarry species, but also showed that the buffalo subsequently declined during the Holocene. The distinct two-phased dynamic inferred here suggests that a major ecological transition occurred in the Holocene. The timing of this transition coincides with the onset of drier conditions throughout tropical Africa following the Holocene Optimum (∼9000-5000 years ago), but also with the explosive growth in human population size associated with the transition from the Palaeolithic to the Neolithic cultural stage. We evaluate each of these possible causal factors and their potential impact on the African megafauna, providing the first systematic assessment of megafauna dynamics on the only continent where large mammals remain abundant. [ABSTRACT FROM AUTHOR]

Large vertebrates are strong interactors in food webs, yet they were lost from most ecosystems after the dispersal of modern humans from Africa and Eurasia. We call for restoration of missing ecological functions and evolutionary potential of lost North American megafauna using extant conspecifics and related taxa. We refer to this restoration as Pleistocene rewilding; it is conceived as carefully managed ecosystem manipulations whereby costs and benefits are objectively addressed on a case-by-case and locality-by-locality basis. Pleistocene rewilding would deliberately promote large, long-lived species over pest and weed assemblages, facilitate the persistence and ecological effectiveness of megafauna on a global scale, and broaden the underlying premise of conservation from managing extinction to encompass restoring ecological and evolutionary processes. Pleistocene rewilding can begin immediately with species such as Bolson tortoises and feral horses and continue through the coming decades with elephants and Holarctic lions. Our exemplar taxa would contribute biological, economic, and cultural benefits to North America. Owners of large tracts of private land in the central and western United States could be the first to implement this restoration. Risks of Pleistocene rewilding include the possibility of altered disease ecology and associated human health implications, as well as unexpected ecological and sociopolitical consequences of reintroductions. Establishment of programs to monitor suites of species interactions and their consequences for biodiversity and ecosystem health will be a significant challenge. Secure fencing would be a major economic cost, and social challenges will include acceptance of predation as an overriding natural process and the incorporation of pre-Columbian ecological frameworks into conservation strategies. [ABSTRACT FROM AUTHOR]

Pollination by animals is a key ecosystem service 1 , 2 and interactions between plants and their pollinators are a model system for studying ecological networks, 3 , 4 yet plant-pollinator networks are typically studied in isolation from the broader ecosystems in which they are embedded. The plants visited by pollinators also interact with other consumer guilds that eat stems, leaves, fruits, or seeds. One such guild, large mammalian herbivores, are well-known ecosystem engineers 5-7 and may have substantial impacts on plant-pollinator networks. Although moderate herbivory can sometimes promote plant diversity, 8 potentially benefiting pollinators, large herbivores might alternatively reduce resource availability for pollinators by consuming flowers, 9 reducing plant density, 10 and promoting somatic regrowth over reproduction. 11 The direction and magnitude of such effects may hinge on abiotic context-in particular, rainfall, which modulates the effects of ungulates on vegetation. 12 Using a long-term, large-scale experiment replicated across a rainfall gradient in central Kenya, we show that a diverse assemblage of native large herbivores, ranging from 5-kg antelopes to 4,000-kg African elephants, limited resource availability for pollinators by reducing flower abundance and diversity; this in turn resulted in fewer pollinator visits and lower pollinator diversity. Exclusion of large herbivores increased floral-resource abundance and pollinator-assemblage diversity, rendering plant-pollinator networks larger, more functionally redundant, and less vulnerable to pollinator extinction. Our results show that species extrinsic to plant-pollinator interactions can indirectly and strongly alter network structure. Forecasting the effects of environmental change on pollination services and interaction webs more broadly will require accounting for the effects of extrinsic keystone species., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Over the last 50,000 years, a majority of megafauna went extinct globally. Only two regions, Africa, and tropical Asia retain megafaunal communities today. Their persistence in Africa has been attributed to co-evolution with hominins, but faunal dynamics are largely understudied in South Asia. Focusing on the Indian Subcontinent and using a novel dataset compiled from the published literature, we report an extremely size biased, but low magnitude extinction during the terminal Pleistocene and early Holocene—approximately 30,000 years after the arrival of Homo sapiens in the region. We document four mammalian extinctions— Palaeoloxodon namadicus , Stegodon namadicus , Hexaprotodon sp., and Equus namadicus ; the extirpation of ostriches (Struthio camelus); and a pseudo-extinction of Indian aurochs (Bos namadicus). The per-capita extinction rate is comparable to eastern and southern Africa, but much lower than elsewhere. Given the long history of hominins in the Indian Subcontinent, and similar extinction patterns to those seen in Africa, we provide the first independent test of the co-evolution hypothesis, and further, suggest that robust population networks and climatic refugia may have allowed for the persistence of megafauna in this region. • Extremely size-biased, but low magnitude extinction in the Indian Subcontinent. • Two proboscideans, a hippo, & a horse go extinct. • Wild cattle are domesticated; ostriches are extirpated. • Extinctions occur in the latest Pleistocene and earliest Holocene. • Longest time lag between H. sapiens arrival and the extinctions outside Africa. [ABSTRACT FROM AUTHOR]

Increasing conflicts and social insecurity are expected to accelerate biodiversity decline and escalate illegal wildlife killing. Sahara‐Sahel megafauna has experienced recent continuous decline due to unsustainable hunting pressure. Here, we provide the best available data on distribution and population trends of threatened, large vertebrates, to illustrate how escalating regional conflict (565% growth since 2011) is hastening population decline in areas that were formerly refugia for megafauna. Without conservation action, the unique and iconic biodiversity of Earth's largest desert will be forever lost. We recommend: (1) establishing strong commitments for change in global attitude toward nature; (2) engraining a culture of environmental responsibility among all stakeholders; (3) fostering environmental awareness to drive societal change; (4) reinforcing regional security and firearms control; and (5) implementing local research and wildlife monitoring schemes. We identify relevant international partners needed to tackle these challenges and to make strong policy change for biodiversity conservation and regional stability. [ABSTRACT FROM AUTHOR]

Large mammalian terrestrial herbivores, such as elephants, have dramatic effects on the ecosystems they inhabit and at high population densities their environmental impacts can be devastating. Pleistocene terrestrial ecosystems included a much greater diversity of megaherbivores (e.g., mammoths, mastodons, giant ground sloths) and thus a greater potential for widespread habitat degradation if population sizes were not limited. Nevertheless, based on modern observations, it is generally believed that populations of megaherbivores (>800 kg) are largely immune to the effects of predation and this perception has been extended into the Pleistocene. However, as shown here, the species richness of big carnivores was greater in the Pleistocene and many of them were significantly larger than their modern counterparts. Fossil evidence suggests that interspecific competition among carnivores was relatively intense and reveals that some individuals specialized in consuming megaherbivores. To estimate the potential impact of Pleistocene large carnivores, we use both historic and modern data on predator-prey body mass relationships to predict size ranges of their typical and maximum prey when hunting as individuals and in groups. These prey size ranges are then compared with estimates of juvenile and subadult proboscidean body sizes derived from extant elephant growth data. Young proboscideans at their most vulnerable age fall within the predicted prey size ranges of many of the Pleistocene carnivores. Predation on juveniles can have a greater impact on megaherbivores because of their long interbirth intervals, and consequently, we argue that Pleistocene carnivores had the capacity to, and likely did, limit megaherbivore population sizes.