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Sura SA, Gehris CG, Liang MY, Lim AN, Fong P. Press versus pulse nutrient supply and species interactions mediate growth of coral reef macroalgae. OIKOS 2023. [DOI: 10.1111/oik.09716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Shayna A. Sura
- Univ. of California Los Angeles, Dept of Ecology and Evolutionary Biology Los Angeles CA USA
- Dauphin Island Sea Lab Dauphin Island AL USA
| | - Connor G. Gehris
- Univ. of California Los Angeles, Dept of Ecology and Evolutionary Biology Los Angeles CA USA
| | - Michelle Y. Liang
- Univ. of California Los Angeles, Dept of Ecology and Evolutionary Biology Los Angeles CA USA
| | - Alexandra N. Lim
- Univ. of California Los Angeles, Dept of Ecology and Evolutionary Biology Los Angeles CA USA
| | - Peggy Fong
- Univ. of California Los Angeles, Dept of Ecology and Evolutionary Biology Los Angeles CA USA
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2
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Honeycutt RN, Holbrook SJ, Brooks AJ, Schmitt RJ. Farmerfish gardens help buffer stony corals against marine heat waves. PLoS One 2023; 18:e0282572. [PMID: 36888598 PMCID: PMC9994727 DOI: 10.1371/journal.pone.0282572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 02/21/2023] [Indexed: 03/09/2023] Open
Abstract
With marine heat waves increasing in intensity and frequency due to climate change, it is important to understand how thermal disturbances will alter coral reef ecosystems since stony corals are highly susceptible to mortality from thermally-induced, mass bleaching events. In Moorea, French Polynesia, we evaluated the response and fate of coral following a major thermal stress event in 2019 that caused a substantial amount of branching coral (predominantly Pocillopora) to bleach and die. We investigated whether Pocillopora colonies that occurred within territorial gardens protected by the farmerfish Stegastes nigricans were less susceptible to or survived bleaching better than Pocillopora on adjacent, undefended substrate. Bleaching prevalence (proportion of the sampled colonies affected) and severity (proportion of a colony's tissue that bleached), which were quantified for >1,100 colonies shortly after they bleached, did not differ between colonies within or outside of defended gardens. By contrast, the fates of 399 focal colonies followed for one year revealed that a bleached coral within a garden was a third less likely to suffer complete colony death and about twice as likely to recover to its pre-bleaching cover of living tissue compared to Pocillopora outside of a farmerfish garden. Our findings indicate that while residing in a farmerfish garden may not reduce the bleaching susceptibility of a coral to thermal stress, it does help buffer a bleached coral against severe outcomes. This oasis effect of farmerfish gardens, where survival and recovery of thermally-damaged corals are enhanced, is another mechanism that helps explain why large Pocillopora colonies are disproportionately more abundant in farmerfish territories than elsewhere in the lagoons of Moorea, despite gardens being relatively uncommon. As such, some farmerfishes may have an increasingly important role in maintaining the resilience of branching corals as the frequency and intensity of marine heat waves continue to increase.
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Affiliation(s)
- Randi N Honeycutt
- Coastal Research Center, Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Sally J Holbrook
- Coastal Research Center, Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
- Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Andrew J Brooks
- Coastal Research Center, Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Russell J Schmitt
- Coastal Research Center, Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
- Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
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Vaughan EJ, Wynn PM, Wilson SK, Williams GJ, Barker PA, Graham NAJ. Precision and cost-effectiveness of bioindicators to estimate nutrient regimes on coral reefs. Mar Pollut Bull 2021; 170:112606. [PMID: 34153852 DOI: 10.1016/j.marpolbul.2021.112606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/01/2021] [Accepted: 06/04/2021] [Indexed: 06/13/2023]
Abstract
Bioindicators are useful for determining nutrient regimes in marine environments, but their ability to evaluate corals reefs in different ecological states is poorly understood. The precision, availability and congruency of eight potential bioindicators (brown macroalgae, green macroalgae, turf algae, cyanobacteria, soft corals, zoanthids, sponges, and sediment) and their stable isotopic and elemental signatures (δ15N, δ13C, %N, %C, and C:N Ratio) were assessed across 21 reefs in the Inner Seychelles. The coefficient of variation (CoV) for δ15N showed that green and brown macroalgae were highly precise (2.47 ± 0.95, n = 11; 4.68 ± 1.33, n = 16, respectively), though were less common on coral-mortality reefs relative to macroalgal-dominated ones. Zoanthids were also highly precise for δ15N (2.98 ± 1.20), but were more readily available regardless of reef state (n = 18). Congruency was low among these indicators, suggesting that different physiological mechanisms for nutrient processing have a stronger influence on a bioindicator's effectiveness than reef state.
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Affiliation(s)
- Eleanor J Vaughan
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
| | - Peter M Wynn
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Shaun K Wilson
- Department of Biodiversity, Conservation and Attractions, Kensington, Perth, Western Australia 6151, Australia; Oceans Institute, University of Western Australia, Crawley, WA 6009, Australia
| | - Gareth J Williams
- School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, UK
| | - Philip A Barker
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
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Sura SA, Molina NE, Blumstein DT, Fong P. Selective consumption of macroalgal species by herbivorous fishes suggests reduced functional complementarity on a fringing reef in Moorea, French Polynesia. J Exp Mar Biol Ecol 2021; 536:151508. [PMID: 35530638 PMCID: PMC9075691 DOI: 10.1016/j.jembe.2020.151508] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Worldwide, many coral reefs are at risk of shifting to degraded algal-dominated states, due to compromised ecological conditions. Functional diversity of herbivorous fishes maintains coral reef health and promotes reef resilience to disturbances. Given previous evidence, it appears the functional roles of herbivorous fishes differ across geographical locations, indicating a need for further assessment of macroalgal consumption by herbivorous fishes. We assessed functional diversity by examining foraging behavior of herbivorous fish species on macroalgae on a fringing reef in Moorea, French Polynesia. We video-recorded choice experiments containing seven common macroalgae and used Strauss' linear resource selection index to determine macroalgal selectivities. We used cluster analysis to identify any distinct groups within herbivorous fish species, given the macroalgal species they targeted, and fitted generalized linear mixed-effects models to identify factors that best predicted the number of bites taken on macroalgae. Seven species from 3 fish families/tribes took a total of 956 bites. Fish species differed in their selectivity with some species (Naso lituratus, N. unicornis, Calatomus carolinus) strongly preferring one or two macroalgal species, while other fish species (Acanthurus nigrofuscus, Ctenochaetus striatus, Chlorurus sordidus, Balistapus undulatus) were less selective. This resulted in fish species forming two clusters. Only 3 of 7 macroalgae were preferred by any fish species, with two fish species both preferring the same two macroalgae. The limited differences in fish species' preferences for different macroalgae suggests limited functional complementarity. Two models (macroalgal species identity+fish functional group, macroalgal species identity+fish species) best predicted the number of bites taken on macroalgae compared to models incorporating only a single explanatory factor or fish family. In the context of this Moorean fringing reef, there is greater functional redundancy than complementarity of herbivorous fishes consuming macroalgae, and the fishes grouped together according to their relative selectivity. We observed fish species that are not classified as browsers consuming macroalgae, suggesting diets of herbivorous fishes may be broader than previously thought. Finally, we observed macroalgal selectivities and consumption that differed from previous studies for the same fish species. Our results contribute to the understanding of functional diversity of herbivorous fishes across coral reefs, and also highlight the need for additional research to further elucidate the role of context and functional diversity of herbivorous fishes consuming macroalgae on coral reefs.
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Affiliation(s)
- Shayna A. Sura
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- corresponding author:
| | - Nury E. Molina
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Daniel T. Blumstein
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Peggy Fong
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
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Fong CR, Sura SA, Ford AT, Howard HB, Molina NE, Smith NN, Fong P. TESTING THE CONCEPTUAL AND OPERATIONAL UNDERPINNINGS OF HERBIVORY ASSAYS: DOES VARIATION IN PREDICTABILITY OF RESOURCES, ASSAY DESIGN, AND DEPLOYMENT METHOD AFFECT OUTCOMES? J Exp Mar Biol Ecol 2020; 533:151469. [PMID: 36936734 PMCID: PMC10019850 DOI: 10.1016/j.jembe.2020.151469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Herbivory assays are a valuable tool used by ecologists to understand many of the patterns and processes affecting herbivory, a widely recognized driving force in marine communities. However, methods vary substantially among studies in both design and operation, and the effect of these differences has yet to be evaluated. We assessed the effects of several key components of assay design on estimates of herbivory to offer four recommendations. First, we found assays out-planted on sequential days in both predictable and random locations within a 60m2 site experienced temporal increases in herbivory by an increasingly diverse assemblage of fishes. Thus, we strongly advise against placing herbivory assays in the same site over a series of days. Second, we found while the amount of biomass consumed in assays was density dependent, the percent loss was not. Thus, we recommend researchers report percent consumption because this metric is robust to differences in biomass offered and will facilitate comparisons across studies. Third, we found associational effects, where proximity of species of differing palatabilities impacted estimates of herbivory rate on one or both species, but these impacts were not consistent across species or sites. Thus, we recommend the effect of association be directly tested for multi specie herbivory assays. Fourth, we found no effect of attachment method on estimates of herbivory rate and recommend researchers continue to use the attachment method in which they are most confident. We hope our experimental results prove useful in the future when designing, conducting, and interpreting herbivory assays.
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Affiliation(s)
- Caitlin R. Fong
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106
- Corresponding author:
| | - Shayna A. Sura
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095
| | - Ashlyn T. Ford
- School of the Environment, Florida Agricultural and Mechanical University, Tallahassee, FL 32307
| | - Hunter B. Howard
- Department of Natural Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853
| | - Nury E. Molina
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095
| | - Nefertiti N. Smith
- Department of Marine and Environmental Science, Hampton University, Hampton, VA 23668
| | - Peggy Fong
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095
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Cappelatti L, Mauffrey ARL, Griffin JN. Functional diversity of habitat formers declines scale-dependently across an environmental stress gradient. Oecologia 2020; 194:135-149. [PMID: 32895733 PMCID: PMC7561580 DOI: 10.1007/s00442-020-04746-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 08/27/2020] [Indexed: 11/27/2022]
Abstract
Marine habitat formers such as seaweeds and corals are lynchpins of coastal ecosystems, but their functional diversity and how it varies with scale and context remains poorly studied. Here, we investigate the functional diversity of seaweed assemblages across the rocky intertidal stress gradient at large (zones) and small (quadrat) scales. We quantified complementary metrics of emergent group richness, functional richness (functional space occupied) and functional dispersion (trait complementarity of dominant species). With increasing shore height, under species loss and turnover, responses of functional diversity were scale- and metric-dependent. At the large scale, functional richness contracted while—notwithstanding a decline in redundancy—emergent group richness and functional dispersion were both invariant. At the small scale, all measures declined, with the strongest responses evident for functional and emergent group richness. Comparisons of observed versus expected values based on null models revealed that functional richness and dispersion were greater than expected in the low shore but converged with expected values higher on the shore. These results show that functional diversity of assemblages of marine habitat formers can be especially responsive to environmental stress gradients at small scales and for richness measures. Furthermore, niche-based processes at the small—neighbourhood—scale can favour co-occurrence of functionally distinctive species under low, but not high, stress, magnifying differences in functional diversity across environmental gradients. As assemblages of marine habitat formers face accelerating environmental change, further studies examining multiple aspects of functional diversity are needed to elucidate patterns, processes, and ecosystem consequences of community (dis-)assembly across diverse groups.
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Affiliation(s)
- Laura Cappelatti
- Biosciences Department, Swansea University, Wallace Building, Swansea, SA2 8PP, Wales, UK.
| | - Alizée R L Mauffrey
- Biosciences Department, Swansea University, Wallace Building, Swansea, SA2 8PP, Wales, UK
| | - John N Griffin
- Biosciences Department, Swansea University, Wallace Building, Swansea, SA2 8PP, Wales, UK
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Fong CR, Gaynus CJ, Carpenter RC. Complex interactions among stressors evolve over time to drive shifts from short turfs to macroalgae on tropical reefs. Ecosphere 2020. [DOI: 10.1002/ecs2.3130] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Caitlin R. Fong
- Department of Biology California State University Northridge Northridge California USA
| | - Camille J. Gaynus
- Department of Ecology and Evolutionary Biology University of California Los Angeles Los Angeles California USA
| | - Robert C. Carpenter
- Department of Ecology and Evolutionary Biology University of California Los Angeles Los Angeles California USA
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Fong CR, Frias M, Goody N, Bittick SJ, Clausing RJ, Fong P. Empirical data demonstrates risk-tradeoffs between landscapes for herbivorous fish may promote reef resilience. Mar Environ Res 2018; 133:1-5. [PMID: 29132921 DOI: 10.1016/j.marenvres.2017.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/26/2017] [Accepted: 11/02/2017] [Indexed: 06/07/2023]
Abstract
Herbivores balance resource requirements with predation risk, which can differ among landscapes; hence, landscape can shape these trade-offs, influencing herbivore distribution and behavior. While this paradigm has been well established on coral-dominated reefs, tropical reefs worldwide are shifting to algal dominance. If herbivores avoid algae due to higher risk and forage in coral, these algal states may be stabilized. However, if herbivores forage more in resource-rich algal states, this may promote coral recovery. We assessed the distribution and behavior of herbivorous fishes in Moorea, French Polynesia in coral and algal turf-dominated fringing reef sites. Acanthuridae were more abundant in coral states and Labridae, tribe Scarinae, in algal turf states, though total fish abundances were equivalent in the two states. Fish in both families spent more time feeding in algal states and hiding/swimming in coral states. Thus, behavior reflects the trade-off between resource acquisition and refuge in these two landscapes and may promote recovery to coral.
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Affiliation(s)
- Caitlin R Fong
- University of California Santa Barbara, Department of Ecology, Evolution, and Marine Biology, 552 University Rd, Santa Barbara, CA 93106, USA.
| | - Matthew Frias
- University of California Los Angeles, Department of Ecology and Evolutionary Biology, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
| | - Nicholas Goody
- University of California Los Angeles, Department of Ecology and Evolutionary Biology, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
| | - Sarah Joy Bittick
- University of California Los Angeles, Department of Ecology and Evolutionary Biology, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
| | - Rachel J Clausing
- University of California Los Angeles, Department of Ecology and Evolutionary Biology, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
| | - Peggy Fong
- University of California Los Angeles, Department of Ecology and Evolutionary Biology, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
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Collado-Vides L, Duran A, Armenis E, Cassano V, Burkepile D, Shantz AA, Palma L, Díaz-Larrea J, Sentíes A, Fujii MT. Seasonal recruitment and survival strategies of Palisada cervicornis comb. nov. (Ceramiales, Rhodophyta) in coral reefs. J Phycol 2017; 53:1087-1096. [PMID: 28733994 DOI: 10.1111/jpy.12567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/30/2017] [Indexed: 06/07/2023]
Abstract
As marine tropical ecosystems deteriorate and lose biodiversity, their communities are shifting to being dominated by a few species, altering ecosystem's functioning and services. Macroalgae are becoming dominant on coral reefs, and are frequently observed outcompeting corals. Turf algal assemblages are the base of energy flow in these systems and one of the most abundant types of macroalgae on coral reefs, but little is known about their biology and diversity. Through molecular and morphological analyses, we identified the turf-forming species Laurencia cervicornis, and by studying seasonal recruitment and the impact of herbivorous fishes on its abundance, we describe its survival strategy. The molecular analyses used a total of 45 rbcL gene sequences including eight current genera within the Laurencia complex and two new sequences of L. cervicornis and strongly support the new combination of Palisada cervicornis comb. nov. In addition, a detailed morphological characterization including the description of reproductive structures is provided. Palisada cervicornis was seen recruiting in all seasons but was typically in low abundance. Specimens grown on tiles in fish exclosure cages were devoured in less than 4 h when offered to fishes. Even though many species of the Laurencia complex have chemicals that deter herbivory, species within the genus Palisada lack feeding deterrents and thus are highly palatable. We suggest that P. cervicornis is a palatable species that seems to survive in the community by obtaining a size-refuge from herbivory within turf communities.
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Affiliation(s)
- Ligia Collado-Vides
- Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, Florida, 33199, USA
| | - Alain Duran
- Department of Biological Sciences, Florida International University, Miami, Florida, 33199, USA
| | - Elizabeth Armenis
- Department of Biological Sciences, Florida International University, Miami, Florida, 33199, USA
| | - Valéria Cassano
- Departamento de Botânica, Universidade de São Paulo, Rua do Matão 277, São Paulo, 05508-900, Brazil
| | - Deron Burkepile
- Department of Ecology, Evolution, & Marine Biology and Marine Science Institute, University of California, Santa Barbara, California, 93106, USA
| | - Andrew A Shantz
- Department of Ecology, Evolution, & Marine Biology and Marine Science Institute, University of California, Santa Barbara, California, 93106, USA
| | - Laura Palma
- Department of Biological Sciences, Florida International University, Miami, Florida, 33199, USA
| | - Jhoana Díaz-Larrea
- Departamento de Hidrobiología, Universidad Autónoma Metropolitana-Iztapalapa, Apdo. Postal 55-535, México D.F, 09340, México
| | - Abel Sentíes
- Departamento de Hidrobiología, Universidad Autónoma Metropolitana-Iztapalapa, Apdo. Postal 55-535, México D.F, 09340, México
| | - Mutue Toyota Fujii
- Núcleo de Pesquisa em Ficologia, Instituto de Botânica, Av. Miguel Estéfano, 3687, São Paulo, 04301-902, Brazil
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Johnson GC, Karajah MT, Mayo K, Armenta TC, Blumstein DT. The bigger they are the better they taste: size predicts predation risk and anti-predator behavior in giant clams. J Zool (1987) 2016. [DOI: 10.1111/jzo.12401] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- G. C. Johnson
- Department of Ecology and Evolutionary Biology; University of California Los Angeles; Los Angeles CA USA
| | - M. T. Karajah
- Department of Ecology and Evolutionary Biology; University of California Los Angeles; Los Angeles CA USA
| | - K. Mayo
- Department of Ecology and Evolutionary Biology; University of California Los Angeles; Los Angeles CA USA
| | - T. C. Armenta
- Department of Ecology and Evolutionary Biology; University of California Los Angeles; Los Angeles CA USA
| | - D. T. Blumstein
- Department of Ecology and Evolutionary Biology; University of California Los Angeles; Los Angeles CA USA
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Fong P, Smith TB, Muthukrishnan R. Algal Dynamics: Alternate Stable States of Reefs in the Eastern Tropical Pacific. In: Glynn PW, Manzello DP, Enochs IC, editors. Coral Reefs of the Eastern Tropical Pacific. Dordrecht: Springer Netherlands; 2017. pp. 339-67. [DOI: 10.1007/978-94-017-7499-4_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Abstract
The factors regulating soil animal communities are poorly understood. Current theory favors niche complementarity and facilitation over competition as the primary forms of non-trophic interspecific interaction in soil fauna; however, competition has frequently been suggested as an important community-structuring factor in earthworms, ecosystem engineers that influence belowground processes. To date, direct evidence of competition in earthworms is lacking due to the difficulty inherent in identifying a limiting resource for saprophagous animals. In the present study, we offer the first direct evidence of interspecific competition for food in this dominant soil detritivore group by combining field observations with laboratory mesocosm experiments using 13C and 15N double-enriched leaf litter to track consumption patterns. In our experiments, the Asian invasive species Amynthas hilgendorfi was a dominant competitor for leaf litter against two European species currently invading the temperate deciduous forests in North America. This competitive advantage may account for recent invasion success of A. hilgendorfi in forests with established populations of European species, and we hypothesize that specific phenological differences play an important role in determining the outcome of the belowground competition. In contrast, Eisenoides lonnbergi, a common native species in the Eastern United States, occupied a unique trophic position with limited interactions with other species, which may contribute to its persistence in habitats dominated by invasive species. Furthermore, our results supported neither the hypothesis that facilitation occurs between species of different functional groups nor the hypothesis that species in the same group exhibit functional equivalency in C and N translocation in the soil. We propose that species identity is a more powerful approach to understand earthworm invasion and its impacts on belowground processes.
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