1
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Xu C, Silliman BR, Chen J, Li X, Thomsen MS, Zhang Q, Lee J, Lefcheck JS, Daleo P, Hughes BB, Jones HP, Wang R, Wang S, Smith CS, Xi X, Altieri AH, van de Koppel J, Palmer TM, Liu L, Wu J, Li B, He Q. Herbivory limits success of vegetation restoration globally. Science 2023; 382:589-594. [PMID: 37917679 DOI: 10.1126/science.add2814] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/21/2023] [Indexed: 11/04/2023]
Abstract
Restoring vegetation in degraded ecosystems is an increasingly common practice for promoting biodiversity and ecological function, but successful implementation is hampered by an incomplete understanding of the processes that limit restoration success. By synthesizing terrestrial and aquatic studies globally (2594 experimental tests from 610 articles), we reveal substantial herbivore control of vegetation under restoration. Herbivores at restoration sites reduced vegetation abundance more strongly (by 89%, on average) than those at relatively undegraded sites and suppressed, rather than fostered, plant diversity. These effects were particularly pronounced in regions with higher temperatures and lower precipitation. Excluding targeted herbivores temporarily or introducing their predators improved restoration by magnitudes similar to or greater than those achieved by managing plant competition or facilitation. Thus, managing herbivory is a promising strategy for enhancing vegetation restoration efforts.
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Affiliation(s)
- Changlin Xu
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China
| | - Brian R Silliman
- Nicholas School of the Environment, Duke University, Beaufort, NC, USA
| | - Jianshe Chen
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China
| | - Xincheng Li
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China
| | - Mads S Thomsen
- Marine Ecology Research Group and Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Department of Bioscience, Aarhus University, Roskilde, Denmark
| | - Qun Zhang
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China
| | - Juhyung Lee
- Marine Science Center, Northeastern University, Nahant, MA, USA
- Department of Oceanography and Marine Research Institute, Pusan National University, Busan, Republic of Korea
| | - Jonathan S Lefcheck
- Tennenbaum Marine Observatories Network and MarineGEO Program, Smithsonian Environmental Research Center, Edgewater, MD, USA
- University of Maryland Center for Environmental Science, Cambridge, MD, USA
| | - Pedro Daleo
- Instituto de Investigaciones Marinas y Costeras (IIMyC), UNMdP, CONICETC, Mar del Plata, Argentina
| | - Brent B Hughes
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
| | - Holly P Jones
- Department of Biological Sciences and Institute for the Study of the Environment, Sustainability, and Energy, Northern Illinois University, DeKalb, IL, USA
| | - Rong Wang
- School of Ecological and Environmental Sciences, Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, East China Normal University, Shanghai, China
| | - Shaopeng Wang
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
| | - Carter S Smith
- Nicholas School of the Environment, Duke University, Beaufort, NC, USA
| | - Xinqiang Xi
- Department of Ecology, School of Life Science, Nanjing University, Nanjing, Jiangsu, China
| | - Andrew H Altieri
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL, USA
| | - Johan van de Koppel
- Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research, Yerseke, Netherlands
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Todd M Palmer
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Lingli Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Jihua Wu
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, and College of Ecology, Lanzhou University, Lanzhou, Gansu, China
| | - Bo Li
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology and Centre for Invasion Biology, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan, China
| | - Qiang He
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China
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2
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Voysey MD, de Bruyn PJN, Davies AB. Are hippos Africa's most influential megaherbivore? A review of ecosystem engineering by the semi-aquatic common hippopotamus. Biol Rev Camb Philos Soc 2023; 98:1509-1529. [PMID: 37095627 DOI: 10.1111/brv.12960] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 04/26/2023]
Abstract
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.
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Affiliation(s)
- Michael D Voysey
- Department of Organismic and Evolutionary Biology, Harvard University, 22 Divinity Avenue, Cambridge, MA, 02138, USA
| | - P J Nico de Bruyn
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Andrew B Davies
- Department of Organismic and Evolutionary Biology, Harvard University, 22 Divinity Avenue, Cambridge, MA, 02138, USA
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3
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Hempson GP, Parr CL, Lehmann CER, Archibald S. Grazing lawns and overgrazing in frequently grazed grass communities. Ecol Evol 2022; 12:e9268. [PMID: 36172293 PMCID: PMC9468907 DOI: 10.1002/ece3.9268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 07/21/2022] [Accepted: 08/05/2022] [Indexed: 11/06/2022] Open
Abstract
Frequent grazing can establish high forage value grazing lawns supporting high grazer densities, but can also produce overgrazed grass communities with unpalatable or low grass basal cover, supporting few grazers. Attempts to create grazing lawns via concentrated grazing, with a goal to increase grazer numbers, are thus risky without knowing how environmental conditions influence the likelihood of each outcome. We collected grass species and trait data from 33 frequently grazed grass communities across eastern South Africa (28 sites) and the Serengeti National Park, Tanzania (five sites), covering wide rainfall (336-987 mm year-1) and soil (e.g., 44%-93% sand) gradients. We identified four grass growth forms using hierarchical clustering on principal components analyses of trait data and assessed trait-environment and growth form-environment relationships using fourth corner and principal components analyses. We distinguished two palatable grass growth forms that both attract yet resist grazers and comprise grazing lawns: (1) "lateral attractors" that spread vegetatively via stolons and rhizomes, and (2) "tufted attractors" that form isolated tufts and may have alternate tall growth forms. By contrast, (3) tough, upright, tufted "resisters," and (4) "avoiders" with sparse architectures or that grow appressed to the soil surface, are of little forage value and avoided by grazers. Grazing lawns occurred across a wide range of conditions, typically comprising lateral attractor grasses in drier, sandy environments, and tufted attractor grasses in wetter, low-sand environments. Resisters occurred on clay-rich soils in mesic areas, while avoiders were widespread but scarce. While grazing lawns can be established under most conditions, monitoring their composition and cover is important, as the potential for overgrazing seems as widely relevant. Tufted attractor-dominated lawns appear somewhat more vulnerable to degradation than lateral attractor-dominated lawns. Increased avoider and resister abundance both reduce forage value, although resisters may provide better soil protection.
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Affiliation(s)
- Gareth P Hempson
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences University of the Witwatersrand Johannesburg South Africa.,South African Environmental Observation Network (SAEON), Ndlovu Node Phalaborwa South Africa
| | - Catherine L Parr
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences University of the Witwatersrand Johannesburg South Africa.,Department of Earth, Ocean & Ecological Sciences University of Liverpool Liverpool UK.,Department of Zoology & Entomology University of Pretoria Pretoria South Africa
| | - Caroline E R Lehmann
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences University of the Witwatersrand Johannesburg South Africa.,School of GeoSciences University of Edinburgh Edinburgh UK.,Tropical Diversity Royal Botanic Garden Edinburgh Edinburgh UK
| | - Sally Archibald
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences University of the Witwatersrand Johannesburg South Africa
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Génin F, Mazza PP, Pellen R, Rabineau M, Aslanian D, Masters JC. Co-evolution assists geographic dispersal: the case of Madagascar. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Interspecific associations may limit the dispersal of individual species, but may also facilitate it when entire co-evolved systems expand their geographic ranges. We tested the recent proposal that episodic land bridges linked Africa and Madagascar at three stages during the Cenozoic by comparing divergence estimates of Madagascar’s angiosperm taxa with their dispersal mechanisms. Plants that rely on gravity for seed dispersal indicate at least two episodes of land connection between Africa and Madagascar, in the Early Palaeocene and Early Oligocene. Seed dispersal by strepsirrhine primates possibly evolved in the Palaeocene, with the divergence of at least one endemic Malagasy angiosperm genus, Burasaia (Menispermaceae). This genus may have facilitated the lemur colonization of Madagascar. Frugivory, nectarivory and gummivory probably generalized in the Oligocene, with the co-evolution of modern lemurs and at least 10 new Malagasy angiosperm families. In the Late Miocene, more angiosperms were probably brought from Africa by birds via a discontinuous land connection, and radiated on Madagascar in diffuse association with birds (asities) and dwarf nocturnal lemurs (cheirogaleids). During the same connective episode, Madagascar was probably colonized by hippopotamuses, which both followed and re-seeded a variety of plants, forming the grassy Uapaca ‘tapia’ forest and ericoid ‘savoka’ thicket.
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Affiliation(s)
- Fabien Génin
- African Primate Initiative for Ecology and Speciation (APIES) and Africa Earth Observatory Network (AEON), Earth Stewardship Science Research Institute, Nelson Mandela University , Gqeberha (Port Elizabeth) , South Africa
| | - Paul Pa Mazza
- Department of Earth Sciences, University of Florence , via La Pira, Florence , Italy
| | - Romain Pellen
- African Primate Initiative for Ecology and Speciation (APIES) and Africa Earth Observatory Network (AEON), Earth Stewardship Science Research Institute, Nelson Mandela University , Gqeberha (Port Elizabeth) , South Africa
| | - Marina Rabineau
- CNRS, Institut Français de Recherche pour l’Exploration de la Mer (IFREMER ), UMR 6538 Geo-Ocean, IUEM, Univ Brest, Plouzané , France
| | - Daniel Aslanian
- CNRS, Institut Français de Recherche pour l’Exploration de la Mer (IFREMER ), UMR 6538 Geo-Ocean, IUEM, Univ Brest, Plouzané , France
| | - Judith C Masters
- African Primate Initiative for Ecology and Speciation (APIES) and Africa Earth Observatory Network (AEON), Earth Stewardship Science Research Institute, Nelson Mandela University , Gqeberha (Port Elizabeth) , South Africa
- Department of Botany & Zoology, Stellenbosch University , Stellenbosch , South Africa
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5
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Inundation area drives hippo group aggregation and dispersal in a seasonal floodplain system. Mamm Biol 2022. [DOI: 10.1007/s42991-022-00286-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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6
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Hippopotamus population trends in Ndumo Game Reserve, South Africa, from 1951 to 2021. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Titcomb GC, Amooni G, Mantas JN, Young HS. The effects of herbivore aggregations at water sources on savanna plants differ across soil and climate gradients. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02422. [PMID: 34288228 DOI: 10.1002/eap.2422] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/29/2021] [Accepted: 03/22/2021] [Indexed: 06/13/2023]
Abstract
Water sources in arid and semiarid ecosystems support humans, wildlife, and domestic animals, forming nodes of activity that sculpt surrounding plant communities and impact critical grazing and soil systems. However, global aridification and changing surface water supply threaten to disrupt these water resources, with strong implications for conservation and management of these ecosystems. To understand how effects of herbivore aggregation at water impact plant communities across contexts, we measured herbivore activity, plant height, cover (trees, grasses, forbs, and bare ground), diversity, and composition at 17 paired water sources and matrix sites across a range of abiotic factors in a semiarid savanna in Kenya. The effects of proximity to surface water and herbivore aggregation on plant communities varied substantially depending on soil and rainfall. In arid areas with nutrient-poor sandy soils, forb and tree cover were 50% lower at water sources compared to neighboring matrix sites, bare ground was 20% higher, species richness was 15% lower, and a single globally important grazing grass (Cynodon dactylon) dominated 60% of transects. However, in mesic areas with nutrient-rich finely textured soils, species richness was 25% higher, despite a 40% increase in bare ground, concurrent with the decline of a dominant tall grass (Themeda triandra) and increase in C. dactylon and other grass species near water sources. Recent rainfall was important for grasses; cover was higher relative to matrix sites only during wet periods, a potential indication of compensatory grazing. These findings suggest that effects of herbivore aggregation on vegetation diversity and composition will vary in magnitude, and in some cases direction, depending on other factors at the site. Where moisture and nutrient resources are high and promote the dominance of few plant species, herbivore aggregations may maintain diversity by promoting grazing lawns and increasing nondominant species cover. However, in arid conditions and sites with low nutrient availability, diversity can be substantially reduced by these aggregations. Our results highlight the importance of considering abiotic conditions when managing for effects of herbivore aggregations near water. This will be particularly important for future managers in light of growing global aridification and surface water changes.
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Affiliation(s)
- Georgia C Titcomb
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, 93106, USA
- Mpala Research Centre, Box 555, Nanyuki, 10400, Kenya
| | | | | | - Hillary S Young
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, 93106, USA
- Mpala Research Centre, Box 555, Nanyuki, 10400, Kenya
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8
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Wang T, Li Z, Wei J, Zheng D, Wang C, Xu C, Chen W, Wang B. Establishment and characterization of fibroblast cultures derived from a female common hippopotamus (Hippopotamus amphibius) skin biopsy. Cell Biol Int 2021; 45:1571-1578. [PMID: 33760319 DOI: 10.1002/cbin.11596] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/15/2021] [Accepted: 03/21/2021] [Indexed: 01/23/2023]
Abstract
The population decline of the common hippopotamus (Hippopotamus amphibius) has necessitated the preservation of their genetic resources for species conservation and research. Of all actions, cryopreservation of fibroblast cell cultures derived from an animal biopsy is considered a simple but efficient means. Nevertheless, preserving viable cell cultures of the common hippopotamus has not been achieved to our knowledge. To this end, we established and characterized fibroblast cell cultures from the skin sample of a newborn common hippopotamus in this study. By combining the tissue explant direct culture and enzymatic digestion methods, we isolated a great number of cells with typical fibroblastic morphology and high viability. Neither bacteria/fungi nor mycoplasma was detectable in the cell cultures throughout the study. The population doubling time was 34 h according to the growth curve. Karyotyping based on Giemsa staining showed that the cultured cells were diploid with 36 chromosomes in all, one pair of which was sex chromosomes. The amplified mitochondrial cytochrome C oxidase subunit I gene sequence of the cultured cells was 99.26% identical with that of the registered H. amphibius complete mitochondrial DNA, confirming the species of origin of the cells. Flow cytometry and immunofluorescence staining results revealed that the detected cells were positive for fibroblast markers, S100A4, and vimentin. In conclusion, we generated the fibroblast cell cultures from a common hippopotamus and identified their characteristics using multiple techniques. We believe the cryopreserved cells could be useful genetic materials for future research.
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Affiliation(s)
- Tao Wang
- Biological Resource Center of Plants, Animals and Microorganisms, China National GeneBank, BGI-Shenzhen, Shenzhen, China.,Shenzhen Key Laboratory of Environmental Microbial Genomics and Application, BGI-Shenzhen, Shenzhen, China
| | - Zelong Li
- Biological Resource Center of Plants, Animals and Microorganisms, China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Jinpu Wei
- Biological Resource Center of Plants, Animals and Microorganisms, China National GeneBank, BGI-Shenzhen, Shenzhen, China.,Shenzhen Key Laboratory of Environmental Microbial Genomics and Application, BGI-Shenzhen, Shenzhen, China
| | - Dongmin Zheng
- Biological Resource Center of Plants, Animals and Microorganisms, China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Chen Wang
- Guangzhou Zoo & Guangzhou Wildlife Research Center, Guangzhou, China
| | - Chang Xu
- Biological Resource Center of Plants, Animals and Microorganisms, China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Wu Chen
- Guangzhou Zoo & Guangzhou Wildlife Research Center, Guangzhou, China
| | - Bo Wang
- Biological Resource Center of Plants, Animals and Microorganisms, China National GeneBank, BGI-Shenzhen, Shenzhen, China.,Shenzhen Key Laboratory of Environmental Microbial Genomics and Application, BGI-Shenzhen, Shenzhen, China
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9
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Isbell LA, Bidner LR, Loftus JC, Kimuyu DM, Young TP. Absentee owners and overlapping home ranges in a territorial species. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-020-02945-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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10
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Fritsch CJ, Downs CT. Evaluation of low‐cost consumer‐grade
UAVs
for conducting comprehensive high‐frequency population censuses of hippopotamus populations. CONSERVATION SCIENCE AND PRACTICE 2020. [DOI: 10.1111/csp2.281] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- Camille J. Fritsch
- Centre for Functional Biodiversity School of Life Sciences, University of KwaZulu‐Natal Scottsville South Africa
| | - Colleen T. Downs
- Centre for Functional Biodiversity School of Life Sciences, University of KwaZulu‐Natal Scottsville South Africa
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11
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12
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Solofondranohatra CL, Vorontsova MS, Hempson GP, Hackel J, Cable S, Vololoniaina J, Lehmann CER. Fire and grazing determined grasslands of central Madagascar represent ancient assemblages. Proc Biol Sci 2020; 287:20200598. [PMID: 32396803 PMCID: PMC7287345 DOI: 10.1098/rspb.2020.0598] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/15/2020] [Indexed: 01/04/2023] Open
Abstract
The ecology of Madagascar's grasslands is under-investigated and the dearth of ecological understanding of how disturbance by fire and grazing shapes these grasslands stems from a perception that disturbance shaped Malagasy grasslands only after human arrival. However, worldwide, fire and grazing shape tropical grasslands over ecological and evolutionary timescales, and it is curious Madagascar should be a global anomaly. We examined the functional and community ecology of Madagascar's grasslands across 71 communities in the Central Highlands. Combining multivariate abundance models of community composition and clustering of grass functional traits, we identified distinct grass assemblages each shaped by fire or grazing. The fire-maintained assemblage is primarily composed of tall caespitose species with narrow leaves and low bulk density. By contrast, the grazer-maintained assemblage is characterized by mat-forming, high bulk density grasses with wide leaves. Within each assemblage, levels of endemism, diversity and grass ages support these as ancient assemblages. Grazer-dependent grasses can only have co-evolved with a now-extinct megafauna. Ironically, the human introduction of cattle probably introduced a megafaunal substitute facilitating modern day persistence of a grazer-maintained grass assemblage in an otherwise defaunated landscape, where these landscapes now support the livelihoods of millions of people.
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Affiliation(s)
- Cédrique L Solofondranohatra
- Laboratoire de Botanique, Département de Biologie et Ecologie Végétales, Faculté des Sciences, Université d'Antananarivo, Antananarivo, Madagascar
- Kew Madagascar Conservation Centre, Antananarivo, Madagascar
| | - Maria S Vorontsova
- Comparative Plant and Fungal Biology, Royal Botanic Gardens Kew, London, UK
| | - Gareth P Hempson
- Centre for African Ecology, School of Animal and Plant Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jan Hackel
- Comparative Plant and Fungal Biology, Royal Botanic Gardens Kew, London, UK
| | - Stuart Cable
- Kew Madagascar Conservation Centre, Antananarivo, Madagascar
- Conservation Science, Royal Botanic Gardens Kew, London, UK
| | - Jeannoda Vololoniaina
- Laboratoire de Botanique, Département de Biologie et Ecologie Végétales, Faculté des Sciences, Université d'Antananarivo, Antananarivo, Madagascar
| | - Caroline E R Lehmann
- Centre for African Ecology, School of Animal and Plant Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of GeoSciences, The University of Edinburgh, Edinburgh, UK
- Tropical Diversity, Royal Botanic Garden Edinburgh, Edinburgh, UK
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13
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Prinsloo AS, Pillay D, O'Riain MJ. Multiscale drivers of hippopotamus distribution in the St Lucia Estuary, South Africa. AFRICAN ZOOLOGY 2020. [DOI: 10.1080/15627020.2020.1717377] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Alexa S Prinsloo
- Marine Research Institute, Department of Biological Sciences, University of Cape Town, South Africa
| | - Deena Pillay
- Marine Research Institute, Department of Biological Sciences, University of Cape Town, South Africa
| | - M Justin O'Riain
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, South Africa
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14
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Spatial ecology of male hippopotamus in a changing watershed. Sci Rep 2019; 9:15392. [PMID: 31659224 PMCID: PMC6817855 DOI: 10.1038/s41598-019-51845-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 10/05/2019] [Indexed: 02/07/2023] Open
Abstract
The obligate dependency of the common hippopotamus, Hippopotamus amphibius, on water makes them particularly vulnerable to hydrological disturbances. Despite the threats facing this at-risk species, there is a lack of information regarding H. amphibius spatial ecology. We used high-resolution tracking data of male H. amphibius to assess home range size, movement mode (e.g. residency and migratory movements), and resource selection patterns. We compared these results across seasons to understand how hydrological variability influences H. amphibius movement. Our study watershed has been severely impacted by anthropogenic water abstraction causing the river to stop flowing for prolonged periods. We observed H. amphibius movements to be highly constrained to the river course with grassy floodplains being their preferred habitat. Dominant and small sub-adult males displayed year-round residency in/near river pools and had smaller home ranges compared to large sub-adults. During the dry season, large sub-adult males made significant (~15 km) upstream movements. The larger home range size of large sub-adults can be attributed to the elevated levels of migratory and exploratory activities to limit conspecific aggression as the river dries. Our observations provide insight into how future changes in water flow may influence male H. amphibius movements and populations through density-dependent effects.
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