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Tebbett SB, Faul SI, Bellwood DR. Quantum of fear: Herbivore grazing rates not affected by reef shark presence. MARINE ENVIRONMENTAL RESEARCH 2024; 196:106442. [PMID: 38484651 DOI: 10.1016/j.marenvres.2024.106442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/07/2024] [Accepted: 03/08/2024] [Indexed: 03/23/2024]
Abstract
Grazing by nominally herbivorous fishes is widely recognised as a critical ecosystem function on coral reefs. However, several studies have suggested that herbivory is reduced in the presence of predators, especially sharks. Nevertheless, the effects of shark presence on grazing, under natural settings, remains poorly resolved. Using ∼200 h of video footage, we quantify the extent of direct disturbance by reef sharks on grazing fishes. Contrary to expectations, grazing rate was not significantly suppressed due to sharks, with fishes resuming feeding in as little as 4 s after sharks passed. Based on our observations, we estimate that an average m2 area of reef at our study locations would be subjected to ∼5 s of acute shark disturbance during daylight hours. It appears the short-term impact of reef shark presence has a negligible effect on herbivore grazing rates, with the variable nature of grazing under natural conditions overwhelming any fear effects.
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Affiliation(s)
- Sterling B Tebbett
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, Queensland, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, Queensland, 4811, Australia.
| | - Sasha I Faul
- College of Science and Engineering, James Cook University, Townsville, Queensland, 4811, Australia
| | - David R Bellwood
- Research Hub for Coral Reef Ecosystem Functions, James Cook University, Townsville, Queensland, 4811, Australia; College of Science and Engineering, James Cook University, Townsville, Queensland, 4811, Australia
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Srivathsa A, Ramachandran V, Saravanan P, Sureshbabu A, Ganguly D, Ramakrishnan U. Topcats and underdogs: intraguild interactions among three apex carnivores across Asia's forestscapes. Biol Rev Camb Philos Soc 2023; 98:2114-2135. [PMID: 37449566 DOI: 10.1111/brv.12998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 06/26/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023]
Abstract
Intraguild interactions among carnivores have long held the fascination of ecologists. Ranging from competition to facilitation and coexistence, these interactions and their complex interplay influence everything from species persistence to ecosystem functioning. Yet, the patterns and pathways of such interactions are far from understood in tropical forest systems, particularly across countries in the Global South. Here, we examined the determinants and consequences of competitive interactions between dholes Cuon alpinus and the two large felids (leopards Panthera pardus and tigers Panthera tigris) with which they most commonly co-occur across Asia. Using a combination of traditional and novel data sources (N = 118), we integrate information from spatial, temporal, and dietary niche dimensions. These three species have faced catastrophic declines in their extent of co-occurrence over the past century; most of their source populations are now confined to Protected Areas. Analysis of dyadic interactions between species pairs showed a clear social hierarchy. Tigers were dominant over dholes, although pack strength in dholes helped ameliorate some of these effects; leopards were subordinate to dholes. Population-level spatio-temporal interactions assessed at 25 locations across Asia did not show a clear pattern of overlap or avoidance between species pairs. Diet-profile assessments indicated that wild ungulate biomass consumption by tigers was highest, while leopards consumed more primate and livestock prey as compared to their co-predators. In terms of prey offtake (ratio of wild prey biomass consumed to biomass available), the three species together harvested 0.4-30.2% of available prey, with the highest offtake recorded from the location where the carnivores reach very high densities. When re-examined in the context of prey availability and offtake, locations with low wild prey availability showed spatial avoidance and temporal overlap among the carnivore pairs, and locations with high wild prey availability showed spatial overlap and temporal segregation. Based on these observations, we make predictions for 40 Protected Areas in India where temporally synchronous estimates of predator and prey densities are available. We expect that low prey availability will lead to higher competition, and in extreme cases, to the complete exclusion of one or more species. In Protected Areas with high prey availability, we expect intraguild coexistence and conspecific competition among carnivores, with spill-over to forest-edge habitats and subsequent prey-switching to livestock. We stress that dhole-leopard-tiger co-occurrence across their range is facilitated through an intricate yet fragile balance between prey availability, and intraguild and conspecific competition. Data gaps and limitations notwithstanding, our study shows how insights from fundamental ecology can be of immense utility for applied aspects like large predator conservation and management of human-carnivore interactions. Our findings also highlight potential avenues for future research on tropical carnivores that can broaden current understanding of intraguild competition in forest systems of Asia and beyond.
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Affiliation(s)
- Arjun Srivathsa
- National Centre for Biological Sciences, TIFR, GKVK Campus, Bellary Road, Bengaluru, 560065, India
- Wildlife Conservation Society-India, 551, 7th Main Road, 2nd Stage Rajiv Gandhi Nagar, Kodigehalli, Bengaluru, 560097, India
| | - Vivek Ramachandran
- National Centre for Biological Sciences, TIFR, GKVK Campus, Bellary Road, Bengaluru, 560065, India
- Wildlife Biology and Conservation Program, National Centre for Biological Sciences, TIFR, GKVK Campus, Bellary Road, Bengaluru, 560065, India
| | - Pooja Saravanan
- National Centre for Biological Sciences, TIFR, GKVK Campus, Bellary Road, Bengaluru, 560065, India
| | - Abhijith Sureshbabu
- National Centre for Biological Sciences, TIFR, GKVK Campus, Bellary Road, Bengaluru, 560065, India
| | - Divyajyoti Ganguly
- National Centre for Biological Sciences, TIFR, GKVK Campus, Bellary Road, Bengaluru, 560065, India
- Wildlife Biology and Conservation Program, National Centre for Biological Sciences, TIFR, GKVK Campus, Bellary Road, Bengaluru, 560065, India
| | - Uma Ramakrishnan
- National Centre for Biological Sciences, TIFR, GKVK Campus, Bellary Road, Bengaluru, 560065, India
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Guerra AS, Van Wert JC, Haupt AJ, McCauley DJ, Eliason EJ, Young HS, Lecchini D, White TD, Caselle JE. Differences in the behavior and diet between shoaling and solitary surgeonfish ( Acanthurus triostegus). Ecol Evol 2023; 13:e9686. [PMID: 36620397 PMCID: PMC9817200 DOI: 10.1002/ece3.9686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 12/05/2022] [Accepted: 12/09/2022] [Indexed: 01/09/2023] Open
Abstract
Variation in behavior within marine and terrestrial species can influence the functioning of the ecosystems they inhabit. However, the contribution of social behavior to ecosystem function remains underexplored. Many coral reef fish species provide potentially insightful models for exploring how social behavior shapes ecological function because they exhibit radical intraspecific variation in sociality within a shared habitat. Here, we provide an empirical exploration on how the ecological function of a shoaling surgeonfish (Acanthurus triostegus) may differ from that of solitary conspecifics on two Pacific coral reefs combining insight from behavioral observations, stable isotope analysis, and macronutrient analysis of gut and fecal matter. We detected important differences in how the social mode of A. triostegus affected its spatial and feeding ecology, as well as that of other reef fish species. Specifically, we found increased distance traveled and area covered by shoaling fish relative to solitary A. triostegus. Additionally, shoaling A. triostegus primarily grazed within territories of other herbivorous fish and had piscivorous and nonpiscivorous heterospecific fish associated with the shoal, while solitary A. triostegus grazed largely grazed outside of any territories and did not have any such interactions with heterospecific fish. Results from stable isotope analysis show a difference in δ15N isotopes between shoaling and solitary fish, which suggests that these different social modes are persistent. Further, we found a strong interaction between social behavior and site and carbohydrate and protein percentages in the macronutrient analysis, indicating that these differences in sociality are associated with measurable differences in both the feeding ecology and nutrient excretion patterns. Our study suggests that the social behavior of individuals may play an important and underappreciated role in mediating their ecological function.
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Affiliation(s)
- Ana Sofia Guerra
- Department of Ecology, Evolution, and Marine BiologyUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
| | - Jacey C. Van Wert
- Department of Ecology, Evolution, and Marine BiologyUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
| | - Alison J. Haupt
- Department of Marine ScienceCalifornia State University Monterey BaySeasideCaliforniaUSA
| | - Douglas J. McCauley
- Department of Ecology, Evolution, and Marine BiologyUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
- Marine Science InstituteUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
| | - Erika J. Eliason
- Department of Ecology, Evolution, and Marine BiologyUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
- Marine Science InstituteUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
| | - Hillary S. Young
- Department of Ecology, Evolution, and Marine BiologyUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
| | - David Lecchini
- EPHE‐UPVD‐CNRSPSL UniversityMo'oreaFrench Polynesia
- Laboratoire d'Excellence "CORAIL"ParisFrance
| | - Timothy D. White
- Hopkins Marine StationStanford UniversityPacific GroveCaliforniaUSA
| | - Jennifer E. Caselle
- Marine Science InstituteUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
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Chow CFY, Wassénius E, Dornelas M, Hoey AS. Species differences drive spatial scaling of foraging patterns in herbivorous reef fishes. OIKOS 2021. [DOI: 10.1111/oik.08713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cher F. Y. Chow
- Centre for Biological Diversity and Scottish Oceans Inst., School of Biology, Univ. of St Andrews St Andrews UK
| | - Emmy Wassénius
- Centre for Biological Diversity and Scottish Oceans Inst., School of Biology, Univ. of St Andrews St Andrews UK
- Global Economic Dynamics and the Biosphere, Royal Swedish Academy of Science Stockholm Sweden
- Stockholm Resilience Center, Stockholm Univ. Stockholm Sweden
| | - Maria Dornelas
- Centre for Biological Diversity and Scottish Oceans Inst., School of Biology, Univ. of St Andrews St Andrews UK
| | - Andrew S. Hoey
- ARC Centre of Excellence for Coral Reef Studies, James Cook Univ. Townsville Queensland Australia
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Munsterman KS, Allgeier JE, Peters JR, Burkepile DE. A View From Both Ends: Shifts in Herbivore Assemblages Impact Top-Down and Bottom-Up Processes on Coral Reefs. Ecosystems 2021. [DOI: 10.1007/s10021-021-00612-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tebbett SB, Goatley CHR, Streit RP, Bellwood DR. Algal turf sediments limit the spatial extent of function delivery on coral reefs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 734:139422. [PMID: 32460082 DOI: 10.1016/j.scitotenv.2020.139422] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/07/2020] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
The presence of key organisms is frequently associated with the delivery of specific ecosystem functions. Areas with such organisms are therefore often considered to have greater levels of these functions. While this assumption has been the backbone of coral reef ecosystem-based management approaches for decades, we currently have only a limited understanding of how fish presence equates to function on coral reefs and whether this relationship is susceptible to stressors. To assess the capacity of a stressor to shape function delivery we used a multi-scale approach ranging from tens of kilometres across the continental shelf of Australia's Great Barrier Reef, down to centimetres within a reef habitat. At each scale, we quantified the spatial extent of a model function (detritivory) by a coral reef surgeonfish (Ctenochaetus striatus) and its potential to be shaped by sediments. At broad spatial scales, C. striatus presence was correlated strongly with algal turf sediment loads, while at smaller spatial scales, function delivery appears to be constrained by algal turf sediment distributions. In all cases, sediment loads above ~250-500 g m-2 were associated with a marked decrease in fish abundance or feeding activity, suggesting that a common ecological threshold lies within this range. Our results reveal a complex functional dynamic between proximate agents of function delivery (fish) and the ultimate drivers of function delivery (sediments), which emphasizes: a) weaknesses in the assumed links between fish presence and function, and b) the multi-scale capacity of algal turf sediments to shape reef processes. Unless direct extractive activities (e.g. fishing) are the main driver of function loss on coral reefs, managing to conserve fish abundance is unlikely to yield the desired outcomes. It only addresses one potential driver. Instead, management of both the agents that deliver functions (e.g. fishes), and the drivers that modify functions (e.g. sediments), is needed.
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Affiliation(s)
- Sterling B Tebbett
- ARC Centre of Excellence for Coral Reef Studies and College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia.
| | - Christopher H R Goatley
- Function, Evolution and Anatomy Research Lab and Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia; Australian Museum Research Institute, Australian Museum, Sydney, New South Wales 2010, Australia
| | - Robert P Streit
- ARC Centre of Excellence for Coral Reef Studies and College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - David R Bellwood
- ARC Centre of Excellence for Coral Reef Studies and College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
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Affiliation(s)
- Margaret A. Malone
- Dept of Biological Sciences, Univ. of Illinois at Chicago 845 West Taylor Street (M/C 066) Chicago IL 60607 USA
- Field Museum of Natural History Chicago IL USA
| | - Abdel H. Halloway
- Dept of Biological Sciences, Univ. of Illinois at Chicago 845 West Taylor Street (M/C 066) Chicago IL 60607 USA
- Dept of Botany and Plant Physiology, Purdue Univ. West Lafayette IN USA
| | - Joel S. Brown
- Dept of Biological Sciences, Univ. of Illinois at Chicago 845 West Taylor Street (M/C 066) Chicago IL 60607 USA
- Integrated Mathematical Oncology, Moffitt Cancer Center Tampa FL USA
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Lesmerises F, Johnson CJ, St‐Laurent M. Effect of behavioral marginality on survival of an alpine ungulate. Ecosphere 2019. [DOI: 10.1002/ecs2.2806] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Frédéric Lesmerises
- Département de Biologie, Chimie et Géographie Centre for Northern Studies Université du Québec à Rimouski 300 Allée des Ursulines Rimouski G5L 3A1 Québec Canada
| | - Chris J. Johnson
- Natural Resources and Environmental Studies Institute University of Northern British Columbia 3333 University Way Prince George British Columbia V2N 4Z9 Canada
| | - Martin‐Hugues St‐Laurent
- Département de Biologie, Chimie et Géographie Centre for Northern Studies & Centre for Forest Research Université du Québec à Rimouski 300 Allée des Ursulines Rimouski Québec G5L 3A1 Canada
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Williams JJ, Papastamatiou YP, Caselle JE, Bradley D, Jacoby DMP. Mobile marine predators: an understudied source of nutrients to coral reefs in an unfished atoll. Proc Biol Sci 2019; 285:rspb.2017.2456. [PMID: 29563260 DOI: 10.1098/rspb.2017.2456] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 02/09/2018] [Indexed: 11/12/2022] Open
Abstract
Animal movements can facilitate important ecological processes, and wide-ranging marine predators, such as sharks, potentially contribute significantly towards nutrient transfer between habitats. We applied network theory to 4 years of acoustic telemetry data for grey reef sharks (Carcharhinus amblyrhynchos) at Palmyra, an unfished atoll, to assess their potential role in nutrient dynamics throughout this remote ecosystem. We evaluated the dynamics of habitat connectivity and used network metrics to quantify shark-mediated nutrient distribution. Predator movements were consistent within year, but differed between years and by sex. Females used higher numbers of routes throughout the system, distributing nutrients over a larger proportion of the atoll. Extrapolations of tagged sharks to the population level suggest that prey consumption and subsequent egestion leads to the heterogeneous deposition of 94.5 kg d-1 of nitrogen around the atoll, with approximately 86% of this probably derived from pelagic resources. These results suggest that sharks may contribute substantially to nutrient transfer from offshore waters to near-shore reefs, subsidies that are important for coral reef health.
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Affiliation(s)
- Jessica J Williams
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
| | - Yannis P Papastamatiou
- Department of Biological Sciences, Florida International University, North Miami, FL 33181, USA
| | - Jennifer E Caselle
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Darcy Bradley
- Bren School of Environmental Science and Management, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - David M P Jacoby
- Zoological Society of London, Institute of Zoology, Regent's Park, London NW1 4RY, UK
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Charalabidis A, Dechaume-Moncharmont FX, Petit S, Bohan DA. Risk of predation makes foragers less choosy about their food. PLoS One 2017; 12:e0187167. [PMID: 29121652 PMCID: PMC5679636 DOI: 10.1371/journal.pone.0187167] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 10/14/2017] [Indexed: 11/18/2022] Open
Abstract
Animals foraging in the wild have to balance speed of decision making and accuracy of assessment of a food item's quality. If resource quality is important for maximizing fitness, then the duration of decision making may be in conflict with other crucial and time consuming tasks, such as anti-predator behaviours or competition monitoring. Individuals facing the risk of predation and/or competition should adjust the duration of decision making and, as a consequence, their level of choosiness for resources. When exposed to predation, the forager could either maintain its level of choosiness for food items but accept a reduction in the amount of food items consumed or it could reduce its level of choosiness and accept all prey items encountered. Under competition risk, individuals are expected to reduce their level of choosiness as slow decision making exposes individuals to a higher risk of opportunity costs. To test these predictions, the level of choosiness of a seed-eating carabid beetle, Harpalus affinis, was examined under 4 different experimental conditions of risk: i) predation risk; ii) intraspecific competition; iii) interspecific competition; and, iv) control. All the risks were simulated using chemical cues from individual conspecifics or beetles of different species that are predatory or granivorous. Our results show that when foraging under the risk of predation, H. affinis individuals significantly reduce their level of choosiness for seeds. Reductions in level of choosiness for food items might serve as a sensible strategy to reduce both the total duration of a foraging task and the cognitive load of the food quality assessment. No significant differences were observed when individuals were exposed to competition cues. Competition, (i.e opportunity cost) may not be perceived as risk high enough to induce changes in the level of choosiness. Our results suggest that considering the amount of items consumed, alone, would be a misleading metric when assessing individual response to a risk of predation. Foraging studies should therefore also take in account the decision making process.
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Affiliation(s)
- Alice Charalabidis
- Agroécologie, AgroSup Dijon, INRA, Université de Bourgogne Franche-Comté, Dijon, France
- Université de Bourgogne Franche-Comté, UMR CNRS 6282 Biogéosciences, Evolutionary Ecology group, Dijon, France
| | | | - Sandrine Petit
- Agroécologie, AgroSup Dijon, INRA, Université de Bourgogne Franche-Comté, Dijon, France
| | - David A. Bohan
- Agroécologie, AgroSup Dijon, INRA, Université de Bourgogne Franche-Comté, Dijon, France
- * E-mail:
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Gilaad RL, Galil BS, Diamant A, Goren M. The diet of native and invasive fish species along the eastern Mediterranean coast (Osteichthyes). ZOOLOGY IN THE MIDDLE EAST 2017. [DOI: 10.1080/09397140.2017.1375196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Roni-Lee Gilaad
- The Department of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Bella S. Galil
- The Steinhardt Museum of Natural History, Tel Aviv University, Tel Aviv, Israel
| | - Ariel Diamant
- National Center for Mariculture, Israel Oceanographic and Limnological Research, Eilat, Israel
| | - Menachem Goren
- The Department of Zoology, Tel Aviv University, Tel Aviv, Israel
- The Steinhardt Museum of Natural History, Tel Aviv University, Tel Aviv, Israel
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