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Leung AJX, Then AYH, Loh KH. Reproductive biology, length-weight relationship and diet of co-occurring butterfly rays, Gymnura poecilura and Gymnura zonura, in Malaysian waters. JOURNAL OF FISH BIOLOGY 2023; 102:564-574. [PMID: 36504128 DOI: 10.1111/jfb.15288] [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: 09/20/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Recent IUCN assessments had resulted in up listing of the status of butterfly rays due to concerns of overfishing, but inadequate biological understanding of these rays prevents meaningful conservation and management measures. Therefore, this study was undertaken to address knowledge gaps in the reproductive biology and diet of longtail butterfly ray (Gymnura poecilura) and zone tail butterfly ray (Gymnura zonura) in Malaysian waters. From surveys of landing sites and fish markets from years 2017 to 2022, size (disc width, DW), weight and maturity were recorded, and stomachs were collected from 94 G. poecilura (N = 39 females and 55 males) and 20 G. zonura (N = 10 females and 10 males) specimens. The length-weight relationships were significantly different between sexes for G. poecilura. The size at maturity (DW50) was estimated to be 476.0 mm (females), 385.0 mm (males) for G. poecilura and 442.0 mm (combined) for G. zonura. The number of embryos ranged from 1 to 6, and the embryo size was between 73.90 to 130.44 mm DW. Dietary analysis of stomach contents revealed that fish prey was dominant in both G. poecilura [94.4% Index of Relative Importance (IRI)] and G. zonura (100% IRI). Ontogenetic shift was seen in G. poecilura that fed on more variety of prey items, including shrimps, squids and crabs with an increase in body size. Both species co-occur all along coastal Malaysia although G. zonura is rarely encountered from fisheries surveys along the Strait of Malacca. Given similar habitat associations and dietary habits, G. poecilura may be able to outcompete G. zonura across their shared habitat range. The validity of G. japonica and G. micrura records in Malaysia remains questionable and requires future investigation.
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Affiliation(s)
- Amanda Jhu-Xhin Leung
- Institute of Ocean and Earth Sciences, Universiti Malaya, Kuala Lumpur, Malaysia
- Institute of Advanced Studies, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Amy Yee-Hui Then
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Kar-Hoe Loh
- Institute of Ocean and Earth Sciences, Universiti Malaya, Kuala Lumpur, Malaysia
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2
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Blandford MI, Hillcoat KB, Pratchett MS, Hoey AS. Effects of habitat fragmentation on the recruitment and early post-settlement survival of coral reef fishes. MARINE ENVIRONMENTAL RESEARCH 2023; 183:105798. [PMID: 36401956 DOI: 10.1016/j.marenvres.2022.105798] [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: 05/31/2022] [Revised: 10/21/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
The combined effects of global climate change and local anthropogenic stressors are leading to increasing loss and fragmentation of habitats. On coral reefs, habitat loss has been shown to influence the abundance and composition of associated fish assemblages, yet few studies have considered how habitat fragmentation may influence reef fish populations and assemblages. Herein, we compared survival, growth and recruitment of reef fish among experimental patches composed of six similar sized colonies of finely branching Pocillopora spp. but with different degrees of fragmentation: coral colonies were clumped (unfragmented), divided into two groups (low fragmentation), three groups (moderate fragmentation) or six groups (high fragmentation). Thirty settlement-stage Pomacentrus amboinensis were tagged, released onto each of the experimental patches, and their survival monitored daily for 11 days. Abundance and species richness of all reef fishes that subsequently recruited to the patches were also recorded, and used to analyse recruitment and community composition. There were no detectable differences among fragmentation treatments in the abundance or composition of reef fish assemblages that recruited to the patches, however, fragmentation influenced the survivorship of P. amboinensis. Highest survival of P. amboinensis was recorded on the unfragmented patches (61%.11 days-1) and highly fragmented habitat patches (54%.11 days-1) and lowest survival on low and moderate fragmentation treatments (47% and 48%.11 days-1, respectively). This suggests that there may be multiple competing processes that moderate mortality (e.g., predation) in unfragmented versus highly fragmented habitats, with moderate levels of habitat fragmentation having the greatest influence on the early post-settlement survival of corsal reef fish.
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Affiliation(s)
- M I Blandford
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville Q, 4811, Australia.
| | - K B Hillcoat
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville Q, 4811, Australia.
| | - M S Pratchett
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville Q, 4811, Australia.
| | - A S Hoey
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville Q, 4811, Australia.
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Yu G, Guo J, Xie W, Wang J, Wu Y, Zhang J, Xu J, Li J. Footedness predicts escape performance in a passerine bird. Ecol Evol 2020; 10:4251-4260. [PMID: 32489594 PMCID: PMC7246196 DOI: 10.1002/ece3.6193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 01/20/2020] [Accepted: 02/14/2020] [Indexed: 12/30/2022] Open
Abstract
Behavioral lateralization, which is associated with the functional lateralization of the two brain hemispheres, commonly exists in animals and can provide an individual with benefits such as enhanced cognition and dual tasking. Lateral bias in limb use, as a type of behavioral lateralization, occur in many species, but the reasons for the coexistence of left- and right-biased individuals in a population remain poorly understood. We examined the footedness of male yellow-bellied tits (Pardaliparus venustulus) when they used feet to clamp mealworms against a perch, and tested its association with other fitness-related behavioral traits (i.e., feeding efficiency, exploration tendency, and escape performance). We expected differently footed individuals to have respective advantages in these behaviors and thereby coexist ("respective advantage" hypothesis). We found their footedness repeatable, and there was no population-level bias. While no associations of feeding efficiency and exploration tendency with footedness were detected, the right-footed individuals were found to be harder to catch than the other individuals. Future studies need to investigate the reasons for the right-footed individuals' superior escape performance. Moreover, the escape advantage for being right-footed and the lack of population-level bias in footedness in male yellow-bellied tits suggest that the benefits related to left footedness also remain to be explored.
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Affiliation(s)
- Gaoyang Yu
- School of Ecology and Nature ConservationBeijing Forestry UniversityBeijingChina
| | - Jinxin Guo
- School of Ecology and Nature ConservationBeijing Forestry UniversityBeijingChina
| | - Wenqian Xie
- School of Ecology and Nature ConservationBeijing Forestry UniversityBeijingChina
| | - Jun Wang
- School of Ecology and Nature ConservationBeijing Forestry UniversityBeijingChina
| | - Yichen Wu
- School of Ecology and Nature ConservationBeijing Forestry UniversityBeijingChina
| | - Jinggang Zhang
- Ministry of Education Key Laboratory for Biodiversity Sciences and Ecological EngineeringCollege of Life SciencesBeijing Normal UniversityBeijingChina
| | - Jiliang Xu
- School of Ecology and Nature ConservationBeijing Forestry UniversityBeijingChina
| | - Jianqiang Li
- School of Ecology and Nature ConservationBeijing Forestry UniversityBeijingChina
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Taylor BM, Choat JH, DeMartini EE, Hoey AS, Marshell A, Priest MA, Rhodes KL, Meekan MG. Demographic plasticity facilitates ecological and economic resilience in a commercially important reef fish. J Anim Ecol 2019; 88:1888-1900. [DOI: 10.1111/1365-2656.13095] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/16/2019] [Accepted: 07/30/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Brett M. Taylor
- Australian Institute of Marine Science Crawley WA Australia
- Joint Institute for Marine and Atmospheric Research NOAA Pacific Islands Fisheries Science Center University of Hawaii Honolulu HI USA
| | - John Howard Choat
- College of Science and Engineering James Cook University Townsville QLD Australia
| | | | - Andrew S. Hoey
- ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville QLD Australia
| | - Alyssa Marshell
- Department of Marine Science and Fisheries College of Agricultural and Marine Science Sultan Qaboos University Muscat Oman
| | - Mark A. Priest
- School of Biological Sciences University of Queensland Brisbane QLD Australia
| | | | - Mark G. Meekan
- Australian Institute of Marine Science Crawley WA Australia
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David V, Joachim S, Tebby C, Porcher JM, Beaudouin R. Modelling population dynamics in mesocosms using an individual-based model coupled to a bioenergetics model. Ecol Modell 2019. [DOI: 10.1016/j.ecolmodel.2019.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Kindinger TL. Invasive predator tips the balance of symmetrical competition between native coral-reef fishes. Ecology 2018; 99:792-800. [PMID: 29490107 DOI: 10.1002/ecy.2173] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 12/18/2017] [Accepted: 01/22/2018] [Indexed: 11/09/2022]
Abstract
The importance of competition and predation in structuring ecological communities is typically examined separately such that interactions between these processes are seldom understood. By causing large reductions in native prey, invasive predators may modify native species interactions. I conducted a manipulative field experiment in The Bahamas to investigate the possibility that the invasive Pacific red lionfish (Pterois volitans) alters competition between planktivorous fairy and blackcap basslets (Gramma loreto and Gramma melacara, respectively). Competition between these coral-reef fishes is known to have symmetrical effects on the juveniles of both species, whereby the feeding positions under reef ledges and growth rates of these individuals are hindered. Following baseline censuses of local populations of competing basslets, I simultaneously manipulated the abundance of lionfish on entire reefs, and the abundance of basslets in local populations under isolated ledges within each reef, resulting in three treatments: unmanipulated control populations of both basslets, reduced abundance of fairy basslet, and reduced abundance of blackcap basslet. For eight weeks, I measured the change in biomass and feeding position of 2-5 cm size classes of each basslet species and calculated the growth rates of ~2 cm individuals using a standard mark-and-recapture method. Experimental populations were filmed at dusk using automated video cameras to quantify the behavior of lionfish overlapping with basslets. Video playback revealed lionfish hunted across all ledge positions, regardless of which basslet species were present, yet lionfish differentially reduced the biomass of only juvenile (2 cm) fairy basslet. Predation reduced the effects of interspecific competition on juvenile blackcap basslet as evidenced by corresponding shifts in feeding position toward coveted front edges of ledges and increases in growth rates that were comparable to the response of these fish in populations where competition was experimentally reduced. Thus, an invasive marine predator altered the outcome of interspecific competition via differential predation, which tipped the balance of competition between native prey species from symmetrical to asymmetrical effects on juveniles. This study reveals a newly demonstrated context in which predation can indirectly facilitate prey, further broadening our understanding of the interactive effects of predation and competition in the context of invasive species.
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Affiliation(s)
- Tye L Kindinger
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, 97331, USA
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San-Jose LM, Peñalver-Alcázar M, Huyghe K, Breedveld MC, Fitze PS. Inter-class competition in stage-structured populations: effects of adult density on life-history traits of adult and juvenile common lizards. Oecologia 2016; 182:1063-1074. [PMID: 27655331 DOI: 10.1007/s00442-016-3738-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 09/16/2016] [Indexed: 11/26/2022]
Abstract
Ecological and evolutionary processes in natural populations are largely influenced by the population's stage-structure. Commonly, different classes have different competitive abilities, e.g., due to differences in body size, suggesting that inter-class competition may be important and largely asymmetric. However, experimental evidence states that inter-class competition, which is important, is rare and restricted to marine fish. Here, we manipulated the adult density in six semi-natural populations of the European common lizard, Zootoca vivipara, while holding juvenile density constant. Adult density affected juveniles, but not adults, in line with inter-class competition. High adult density led to lower juvenile survival and growth before hibernation. In contrast, juvenile survival after hibernation was higher in populations with high adult density, pointing to relaxed inter-class competition. As a result, annual survival was not affected by adult density, showing that differences in pre- and post-hibernation survival balanced each other out. The intensity of inter-class competition affected reproduction, performance, and body size in juveniles. Path analyses unravelled direct treatment effects on early growth (pre-hibernation) and no direct treatment effects on the parameters measured after hibernation. This points to allometry of treatment-induced differences in early growth, and it suggests that inter-class competition mainly affects the early growth of the competitively inferior class and thereby their future performance and reproduction. These results are in contrast with previous findings and, together with results in marine fish, suggest that the strength and direction of density dependence may depend on the degree of inter-class competition, and thus on the availability of resources used by the competing classes.
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Affiliation(s)
- Luis M San-Jose
- Department of Ecology and Evolution, University of Lausanne, Le Biophore, 1015, Lausanne, Switzerland.
| | - Miguel Peñalver-Alcázar
- Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (MNCN, CSIC), José Gutiérrez Abascal 2, 28006, Madrid, Spain
| | - Katleen Huyghe
- Department of Biology, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium
| | - Merel C Breedveld
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales (MNCN, CSIC), José Gutiérrez Abascal 2, 28006, Madrid, Spain
- Instituto Pirenaico de Ecología (MNCN, CSIC), Ntra. Señora de la Victoria, 22700, Jaca, Spain
| | - Patrick S Fitze
- Department of Ecology and Evolution, University of Lausanne, Le Biophore, 1015, Lausanne, Switzerland
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales (MNCN, CSIC), José Gutiérrez Abascal 2, 28006, Madrid, Spain
- Instituto Pirenaico de Ecología (MNCN, CSIC), Ntra. Señora de la Victoria, 22700, Jaca, Spain
- Fundación Araid, Edificio CEEI Aragón, María de Luna 11, 50018, Zaragoza, Spain
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Kessel ST, Hansell AC, Gruber SH, Guttridge TL, Hussey NE, Perkins RG. Three decades of longlining in Bimini, Bahamas, reveals long-term trends in lemon shark Negaprion brevirostris (Carcharhinidae) catch per unit effort. JOURNAL OF FISH BIOLOGY 2016; 88:2144-2156. [PMID: 27245624 DOI: 10.1111/jfb.12987] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/18/2016] [Indexed: 06/05/2023]
Abstract
In Bimini, Bahamas, the consistent employment of longlines, beginning in 1982, provided a rare opportunity to explore population trends for large resident sharks. This study assessed three shallow water longline survey periods at this location; 1982-1989, 1992-2002 and 2003-2014, with the aim of determining trends in annual catch per unit effort (CPUE) for an IUCN listed near-threatened species, the lemon shark Negaprion brevirostris. A general additive model (GAM) was used to analyse the non-linear annual CPUE values over the entire 32-year research period. The GAM displayed high variability of annual CPUE, with a peak value of 0·026 N. brevirostris per hook day (hooks day(-1) ) in 2000. The temporal pattern of CPUE indicated an abundance trend with a complete cycle, from trough to trough, occurring over a period of approximately 18 years. The 1982-1989 survey period saw the highest proportion of mature individuals (19·8%) and the smallest average pre-caudal length (LPC ; 124·8 cm). The 1992-2002 survey period had the highest average annual CPUE (0·018 hooks day(-1) ), while the 2003-2014 research period saw largest average LPC size (134·8 cm) and the lowest average CPUE values (0·009 hooks day(-1) ) of the entire research period. The long-term trend identified in this study provides a baseline for future assessment.
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Affiliation(s)
- S T Kessel
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, N9B 3P4, Canada
- School of Earth and Ocean Sciences, Cardiff University, Cardiff, CF10 3AT, U.K
| | - A C Hansell
- School for Marine Science and Technology, University of Massachusetts-Dartmouth, Fairhaven, MA, U.S.A
| | - S H Gruber
- Bimini Biological Field Station Foundation, South Bimini, Bahamas
| | - T L Guttridge
- Bimini Biological Field Station Foundation, South Bimini, Bahamas
| | - N E Hussey
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, N9B 3P4, Canada
| | - R G Perkins
- School of Earth and Ocean Sciences, Cardiff University, Cardiff, CF10 3AT, U.K
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Hall A, Kingsford M. Predators Exacerbate Competitive Interactions and Dominance Hierarchies between Two Coral Reef Fishes. PLoS One 2016; 11:e0151778. [PMID: 26992169 PMCID: PMC4798715 DOI: 10.1371/journal.pone.0151778] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 03/03/2016] [Indexed: 11/18/2022] Open
Abstract
Predation and competition are critical processes influencing the ecology of organisms, and can play an integral role in shaping coral reef fish communities. This study compared the relative and interacting effects of competition and predation on two competing species of coral reef fish, Pomacentrus amboinensis and P. moluccensis (Pomacentridae), using a multifactorial experiment. Fish were subjected to the sight and smell of a known predator (Pseudochromis fuscus), the presence of the heterospecific competitor (i.e., P. amboinensis vs. P. moluccensis), or a combination of the two for a period of 19 days. The sub-lethal effects of predator/competitor treatments were compared with controls; a combination of otolith microstructure analysis and observations were used to determine otolith growth patterns and behaviour. We predicted that the stress of competition and/or predation would result in strong sub-lethal impacts, and act synergistically on growth and behavioural patterns. We found strong evidence to support this prediction, but only for P. amboinensis, which suffered reductions in growth in both predator and competitor treatments, with the largest reductions occurring when subjected to both predation and competition concurrently. There was strong evidence of asymmetrical competition between the two damselfish species, with P. moluccensis as the dominant competitor, displaying strong aggressive behaviour towards P. amboinensis. Growth reductions for P. amboinensis in predator/competitor treatments appeared to come about primarily due to increases in shelter seeking behaviour, which significantly reduced the foraging rates of individuals compared with controls. These data highlight the importance of predator/competitor synergisms in influencing key behaviours and demographic parameters for juvenile coral reef fishes.
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Affiliation(s)
- April Hall
- College of Marine and Environmental Science and Centre of Excellence in Coral Reef Studies, James Cook University, Townsville, QLD, Australia 4811
- * E-mail:
| | - Michael Kingsford
- College of Marine and Environmental Science and Centre of Excellence in Coral Reef Studies, James Cook University, Townsville, QLD, Australia 4811
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Bonin MC, Boström-Einarsson L, Munday PL, Jones GP. The Prevalence and Importance of Competition Among Coral Reef Fishes. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2015. [DOI: 10.1146/annurev-ecolsys-112414-054413] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although competition is recognized as a core ecological process, its prevalence and importance in coral reef fish communities have been debated. Here we compile and synthesize the results of 173 experimental tests of competition from 72 publications. We show that evidence for competition is pervasive both within and between species, with 72% of intraspecific tests and 56% of interspecific tests demonstrating a demographically significant consequence of competition (e.g., a decrease in recruitment, survival, growth, or fecundity). We highlight several factors that can interact with the effects of competition and make it more difficult to detect in field experiments. In light of this evidence, we discuss the role of competition in shaping coral reef fish communities and competition's status as one of several processes that contribute to species coexistence. Finally, we consider some of the complex ways that climate change may influence competition, and we provide suggestions for future research.
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Affiliation(s)
- Mary C. Bonin
- Australian Research Council Center of Excellence for Coral Reef Studies and College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Lisa Boström-Einarsson
- Australian Research Council Center of Excellence for Coral Reef Studies and College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Philip L. Munday
- Australian Research Council Center of Excellence for Coral Reef Studies and College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Geoffrey P. Jones
- Australian Research Council Center of Excellence for Coral Reef Studies and College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
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11
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Asymmetries in body condition and order of arrival influence competitive ability and survival in a coral reef fish. Oecologia 2015. [DOI: 10.1007/s00442-015-3401-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Matthews SA, Wong MYL. Temperature-dependent resolution of conflict over rank within a size-based dominance hierarchy. Behav Ecol 2015. [DOI: 10.1093/beheco/arv042] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Boström-Einarsson L, Bonin MC, Munday PL, Jones GP. Habitat degradation modifies the strength of interspecific competition in coral dwelling damselfishes. Ecology 2014. [DOI: 10.1890/13-1345.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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14
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Messmer V, Blowes SA, Jones GP, Munday PL. Experimental evaluation of diversity–productivity relationships in a coral reef fish assemblage. Oecologia 2014; 176:237-49. [DOI: 10.1007/s00442-014-2992-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/04/2014] [Indexed: 11/29/2022]
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15
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Poulos DE, McCormick MI. Who wins in the battle for space? The importance of priority, behavioural history and size. Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Ford JR, Swearer SE. Two's company, three's a crowd: food and shelter limitation outweigh the benefits of group living in a shoaling fish. Ecology 2013; 94:1069-77. [PMID: 23858647 DOI: 10.1890/12-1891.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Identifying how density and number-dependent processes regulate populations is important for predicting population response to environmental change. Species that live in groups, such as shoaling fish, can experience both direct density-dependent mortality through resource limitation and inverse number-dependent mortality via increased feeding rates and predator evasion in larger groups. To investigate the role of these processes in a temperate reef fish population, we manipulated the density and group size of the shoaling species Trachinops caudimaculatus on artificial patch reefs at two locations with different predator fields in Port Phillip Bay, Australia. We compared mortality over four weeks to estimates of predator abundance and per capita availability of refuge and food to identify mechanisms for density or number dependence. Mortality was strongly directly density dependent throughout the experiment, regardless of the dominant predator group; however, the limiting resource driving this effect changed over time. In the first two weeks when densities were highest, density-dependent mortality was best explained by refuge competition and the abundance of benthic predators. During the second two weeks, food competition best explained the pattern of mortality. We detected no effect of group size at either location, even where pelagic-predator abundance was high. Overall, direct density effects were much stronger than those of group size, suggesting little survival advantage to shoaling on isolated patch reefs where resource competition is high. This study is the first to observe a temporal shift in density-dependent mechanisms in reef fish, and the first to observe food limitation on short temporal scales. Food competition may therefore be an important regulator of postsettlement reef fish cohorts after the initial intense effects of refuge limitation and predation.
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Affiliation(s)
- John R Ford
- Department of Zoology, Melbourne University, Parkville, Victoria, 3010 Australia.
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Kaspersson R, Höjesjö J, Bohlin T. Habitat exclusion and reduced growth: a field experiment on the effects of inter-cohort competition in young-of-the-year brown trout. Oecologia 2012; 169:733-42. [PMID: 22271199 DOI: 10.1007/s00442-012-2248-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 01/03/2012] [Indexed: 11/28/2022]
Abstract
Competition during the juvenile phase is a key process for regulating density in organisms with high fecundity. Juvenile density-dependent bottlenecks may become even more pronounced if several cohorts compete, but this has received relatively limited attention in previous literature. We performed a manipulation experiment in seven coastal streams to investigate the presence of inter-cohort competition, using habitat selection, body-size and density of newly emerged (age-0) brown trout (Salmo trutta) as response variables. The trout population (age ≥ 1 fish) was estimated using electro-fishing prior to the emergence of fry (April-May) and was either removed (manipulated sections) or maintained (control sections). Age-0 habitat selection was examined in June while density and body-size was evaluated in October (end of the growth season). We found that age-0 trout selected habitats that were located further from riffles (nursery habitats) in the absence of age ≥ 1 trout, suggesting a niche overlap between cohorts in the habitat dimension and, hence, that both inter-cohort competitive interactions and ontogenetic preference may influence habitat utilisation in the wild. Furthermore, we also found age-0 body-size to be significantly larger in manipulated sections and negatively related to its own density. We argue that competition from older cohorts influence the availability of age-0 feeding territories at the critical phase of emergence with secondary negative effects on age-0 growth. These results not only have implications for understanding the mechanisms of density dependence but can also provide valuable knowledge to the management of salmonid populations and their habitats in the wild.
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Affiliation(s)
- Rasmus Kaspersson
- Department of Zoology, University of Gothenburg, Box 463, 405 30, Göteborg, Sweden.
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18
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The spatial scale of competition from recruits on an older cohort in Atlantic salmon. Oecologia 2011; 167:1017-25. [PMID: 21710118 PMCID: PMC3213340 DOI: 10.1007/s00442-011-2055-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 06/08/2011] [Indexed: 11/05/2022]
Abstract
Competitive effects of younger cohorts on older ones are frequently assumed to be negligible in species where older, larger individuals dominate in pairwise behavioural interactions. Here, we provide field estimates of such competition by recruits on an older age class in Atlantic salmon (Salmo salar), a species where observational studies have documented strong body size advantages which should favour older individuals in direct interactions. By creating realistic levels of spatial variation in the density of underyearling (YOY) recruits over a 1-km stretch of a stream, and obtaining accurate measurements of individual growth rates of overyearlings (parr) from capture–mark–recapture data on a fine spatial scale, we demonstrate that high YOY density can substantially decrease parr growth. Models integrating multiple spatial scales indicated that parr were influenced by YOY density within 16 m. The preferred model suggested parr daily mass increase to be reduced by 39% when increasing YOY density from 0.0 to 1.0 m−2, which is well within the range of naturally occurring densities. Reduced juvenile growth rates will in general be expected to reduce juvenile survival (via increased length of exposure to freshwater mortality) and increase generation times (via increased age at seaward migrations). Thus, increased recruitment can significantly affect the performance of older cohorts, with important implications for population dynamics. Our results highlight that, even for the wide range of organisms that rely on defendable resources, the direction of competition among age classes cannot be assumed a priori or be inferred from behavioural observations alone.
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White JW, Samhouri JF, Stier AC, Wormald CL, Hamilton SL, Sandin SA. Synthesizing mechanisms of density dependence in reef fishes: behavior, habitat configuration, and observational scale. Ecology 2010; 91:1949-61. [PMID: 20715614 DOI: 10.1890/09-0298.1] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Coral and rocky reef fish populations are widely used as model systems for the experimental exploration of density-dependent vital rates, but patterns of density-dependent mortality in these systems are not yet fully understood. In particular, the paradigm for strong, directly density-dependent (DDD) postsettlement mortality stands in contrast to recent evidence for inversely density-dependent (IDD) mortality. We review the processes responsible for DDD and IDD per capita mortality in reef fishes, noting that the pattern observed depends on predator and prey behavior, the spatial configuration of the reef habitat, and the spatial and temporal scales of observation. Specifically, predators tend to produce DDD prey mortality at their characteristic spatial scale of foraging, but prey mortality is IDD at smaller spatial scales due to attack-abatement effects (e.g., risk dilution). As a result, DDD mortality may be more common than IDD mortality on patch reefs, which tend to constrain predator foraging to the same scale as prey aggregation, eliminating attack-abatement effects. Additionally, adjacent groups of prey on continuous reefs may share a subset of refuges, increasing per capita refuge availability and relaxing DDD mortality relative to prey on patch reefs, where the patch edge could prevent such refuge sharing. These hypotheses lead to a synthetic framework to predict expected mortality patterns for a variety of scenarios. For nonsocial, nonaggregating species and species that aggregate in order to take advantage of spatially clumped refuges, IDD mortality is possible but likely superseded by DDD refuge competition, especially on patch reefs. By contrast, for species that aggregate socially, mortality should be IDD at the scale of individual aggregations but DDD at larger scales. The results of nearly all prior reef fish studies fit within this framework, although additional work is needed to test many of the predicted outcomes. This synthesis reconciles some apparent contradictions in the recent reef fish literature and suggests the importance of accounting for the scale-sensitive details of predator and prey behavior in any study system.
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Affiliation(s)
- J Wilson White
- Department of Wildlife, Fish, and Conservation Biology, University of California-Davis, Bodega Marine Laboratory, Bodega Bay, California 94923, USA.
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Bassar RD, López-Sepulcre A, Walsh MR, Turcotte MM, Torres-Mejia M, Reznick DN. Bridging the gap between ecology and evolution: integrating density regulation and life-history evolution. Ann N Y Acad Sci 2010; 1206:17-34. [DOI: 10.1111/j.1749-6632.2010.05706.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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MUGABO M, MARQUIS O, PERRET S, LE GALLIARD JF. Immediate and delayed life history effects caused by food deprivation early in life in a short-lived lizard. J Evol Biol 2010; 23:1886-98. [DOI: 10.1111/j.1420-9101.2010.02052.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Kaspersson R, Höjesjö J, Pedersen S. Effects of density on foraging success and aggression in age-structured groups of brown trout. Anim Behav 2010. [DOI: 10.1016/j.anbehav.2009.12.025] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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McCormick MI. Behaviourally mediated phenotypic selection in a disturbed coral reef environment. PLoS One 2009; 4:e7096. [PMID: 19763262 PMCID: PMC2740825 DOI: 10.1371/journal.pone.0007096] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 08/20/2009] [Indexed: 11/18/2022] Open
Abstract
Natural and anthropogenic disturbances are leading to changes in the nature of many habitats globally, and the magnitude and frequency of these perturbations are predicted to increase under climate change. Globally coral reefs are one of the most vulnerable ecosystems to climate change. Fishes often show relatively rapid declines in abundance when corals become stressed and die, but the processes responsible are largely unknown. This study explored the mechanism by which coral bleaching may influence the levels and selective nature of mortality on a juvenile damselfish, Pomacentrus amboinensis, which associates with hard coral. Recently settled fish had a low propensity to migrate small distances (40 cm) between habitat patches, even when densities were elevated to their natural maximum. Intraspecific interactions and space use differ among three habitats: live hard coral, bleached coral and dead algal-covered coral. Large fish pushed smaller fish further from the shelter of bleached and dead coral thereby exposing smaller fish to higher mortality than experienced on healthy coral. Small recruits suffered higher mortality than large recruits on bleached and dead coral. Mortality was not size selective on live coral. Survival was 3 times as high on live coral as on either bleached or dead coral. Subtle behavioural interactions between fish and their habitats influence the fundamental link between life history stages, the distribution of phenotypic traits in the local population and potentially the evolution of life history strategies.
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Affiliation(s)
- Mark I McCormick
- ARC Centre of Excellence for Coral Reef Studies and School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, Australia.
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Kaspersson R, Höjesjö J. Density-dependent growth rate in an age-structured population: a field study on stream-dwelling brown trout Salmo trutta. JOURNAL OF FISH BIOLOGY 2009; 74:2196-2215. [PMID: 20735548 DOI: 10.1111/j.1095-8649.2009.02227.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A field experiment during autumn, winter and spring was performed in a small stream on the west coast of Sweden, aiming to examine the direct and indirect consequences of density-dependent intercohort competition in brown trout Salmo trutta. Individual growth rate, recapture rate and site fidelity were used as response variables in the young-of-the-year (YOY) age class, experiencing two different treatments: presence or absence of yearlings and over-yearlings (age > or = 1+ year individuals). YOY individuals in stream sections with reduced density of age > or = 1+ year individuals grew significantly faster than individuals experiencing natural cohort structure. In the latter, growth rate was negatively correlated with density and biomass of age > or = 1+ year individuals, which may induce indirect effects on year-class strength through, for example, reduced fecundity and survival. Movement of YOY individuals and turnover rate (i.e. proportion of untagged individuals) were used to demonstrate potential effects of intercohort competition on site fidelity. While YOY movement was remarkably restricted (83% recaptured within 50 m from the release points), turnover rate was higher in sections with reduced density of age > or = 1+ year individuals, suggesting that reduced density of age > or = 1+ year individuals may have released favourable microhabitats.
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Affiliation(s)
- R Kaspersson
- Department of Zoology, Animal Ecology, University of Gothenburg, P. O. Box 463, SE-40530 Gothenburg, Sweden.
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Samhouri JF, Steele MA, Forrester GE. Inter-cohort competition drives density dependence and selective mortality in a marine fish. Ecology 2009; 90:1009-20. [DOI: 10.1890/07-1161.1] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Vigliola L, Doherty PJ, Meekan MG, Drown DM, Jones ME, Barber PH. GENETIC IDENTITY DETERMINES RISK OF POST-SETTLEMENT MORTALITY OF A MARINE FISH. Ecology 2007; 88:1263-77. [PMID: 17536412 DOI: 10.1890/06-0066] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Longitudinal sampling of four cohorts of Neopomacentrus filamentosus, a common tropical damselfish from Dampier Archipelago, Western Australia, revealed the evolution of size structure after settlement. Light traps collected premetamorphic individuals from the water column ("settlers") to establish a baseline for each cohort. Subsequently, divers collected benthic juveniles ("recruits") at 1-3-month intervals to determine the relative impacts of post-settlement mortality during the first three months. Growth trajectories for individual fish were back-calculated from otolith records and compared with nonlinear mixed-effects models. Size-selective mortality was detected in all cohorts with the loss of smaller, slower growing individuals. Three months after settlement, recruits showed significantly faster growth as juveniles, faster growth as larvae, and larger sizes as hatchlings. The timing and intensity of post-settlement selection differed among cohorts and was correlated with density at settlement. The cohort with the greatest initial abundance experienced the strongest selective mortality, with most of this mortality occurring between one and two months after settlement when juveniles began foraging at higher positions in the water column. Significant genetic structure was found between settlers and three-month-old recruits in this cohort as a result of natural selection that changed the frequency of mtDNA haplotypes measured at the control region. The extent of this genetic difference was enlarged or reduced by artificially manipulating the intensity of size-based selection, thus establishing a link between phenotype and haplotype. Sequence variation in the control region of the mitochondrial genome has been linked to mitochondrial efficiency and weight gain in other studies, which provides a plausible explanation for the patterns observed here.
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Affiliation(s)
- Laurent Vigliola
- Australian Institute of Marine Science, P.O. Box 40197, Casuarina MC Darwin NT 0811, Australia.
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Cameron TC, Wearing HJ, Rohani P, Sait SM. Two-species asymmetric competition: effects of age structure on intra- and interspecific interactions. J Anim Ecol 2007; 76:83-93. [PMID: 17184356 DOI: 10.1111/j.1365-2656.2006.01185.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. The patterns of density-dependent resource competition and the mechanisms leading to competitive exclusion in an experimental two-species insect age-structured interaction were investigated. 2. The modes of competition (scramble or contest) and strength of competition (under- to overcompensatory) operating within and between the stages of the two species was found to be influenced by total competitor density, the age structure of the competitor community and whether competition is between stages of single or two species. 3. The effect of imposed resource limitation on survival was found to be asymmetric between stages and species. Environments supporting both dominant and subordinate competitors were found to increase survival of subordinate competitors at lower total competitor densities. Competitive environments during development within individual stage cohorts (i.e. small or large larvae), differed from the competitive environment in lumped age classes (i.e. development from egg-->pupae). 4. Competition within mixed-age, stage or species cohorts, when compared with uniform-aged or species cohorts, altered the position of a competitive environment on the scramble-contest spectrum. In some cases the competitive environment switched from undercompensatory contest to overcompensatory scramble competition. 5. Such switching modes of competition suggest that the relative importance of the mechanisms regulating single-species population dynamics (i.e. resource competition) may change when organisms are embedded within a wider community.
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Affiliation(s)
- Tom C Cameron
- Genetics, Ecology & Evolution Research Group, Institute of Integrative & Comparative Biology, University of Leeds, Leeds, LS2 9JT, UK.
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Eitam A, Blaustein L, Mangel M. Density and intercohort priority effects on larval Salamandra salamandra in temporary pools. Oecologia 2005; 146:36-42. [PMID: 16133198 DOI: 10.1007/s00442-005-0185-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Accepted: 06/08/2005] [Indexed: 10/25/2022]
Abstract
Priority effects, i.e., effects of an early cohort on the performance of a later cohort, are generally studied between, and not within, species. The paucity of intraspecific assessments does not reflect a lack of ecological importance, but the technical problem associated with differentiating between conspecific cohorts. Here, we examine priority and density-dependent effects on larval Salamandra salamandra infraimmaculata. Larvae deposited by their mother early in the season have increased risk of desiccation, as rains at the beginning of the season are less frequent and unpredictable. However, breeding later may incur a high cost through conspecific priority effects, including cannibalism and competition. In an outdoor artificial pool experiment, we established densities of 0, 1, 2, 4 or 6 newly born larvae per pool ( approximately 30 l), and 40 days later, added a second cohort of three newly born larvae to each pool. We differentiated between cohorts using natural individual-specific markings. For the early cohort, increasing density decreased survival and size at metamorphosis, and increased time to metamorphosis. For the late cohort, survival was 100% in pools without early-cohort larvae, but ranged between 13 and 33% in the presence of early-cohort larvae. Time to metamorphosis was significantly longer in the presence of low vs high densities of early-cohort larvae. Results suggest that early-cohort larvae are mainly subjected to exploitative competition and cannibalism mediated by food limitation, and that late-cohort larvae are subjected to cannibalism and interference due to size asymmetry between cohorts. The strong priority effects suggest that Salamandra females could increase their fitness by adjusting the number of larvae they deposit in specific pools to avoid cannibalism and intraspecific competition.
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Affiliation(s)
- Avi Eitam
- Community Ecology Laboratory, Institute of Evolution, Faculty of Science and Science Education, University of Haifa, 31905, Haifa, Israel.
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