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Nutrient enrichment favors grazing selectivity and nutritional mismatch in a plankton community. THEOR ECOL-NETH 2023. [DOI: 10.1007/s12080-023-00556-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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2
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Smith S, Mohamed A, Amaral JR, Kusi N, Smith A, Gordon SP, López-Sepulcre A. Rapid evolution of diet choice in an introduced population of Trinidadian guppies. Biol Lett 2023; 19:20220443. [PMID: 36693425 PMCID: PMC9873468 DOI: 10.1098/rsbl.2022.0443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/16/2022] [Indexed: 01/26/2023] Open
Abstract
Eco-evolutionary theory has brought an interest in the rapid evolution of functional traits. Among them, diet is an important determinant of ecosystem structure, affecting food web dynamics and nutrient cycling. However, it is largely unknown whether diet, or diet preference, has a hereditary basis and can evolve on contemporary timescales. Here, we study the diet preferences of Trinidadian guppies Poecilia reticulata collected from directly below an introduction site of fish transplanted from a high-predation environment into a low predation site where their densities and competition increased. Behavioural assays on F2 common garden descendants of the ancestral and derived populations showed that diet preference has rapidly evolved in the introduced population in only 12 years (approx. 36 generations). Specifically, we show that the preference for high-quality food generally found in high-predation guppies is lost in the newly derived low-predation population, who show an inertia toward the first encountered food. This result is predicted by theory stating that organisms should evolve less selective diets under higher competition. Demonstrating that diet preference can show rapid and adaptive evolution is important to our understanding of eco-evolutionary feedbacks and the role of evolution in ecosystem dynamics.
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Affiliation(s)
- Shawna Smith
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Amina Mohamed
- Department of Biology, Washington University, St. Louis, MO 63130, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jeferson Ribeiro Amaral
- Department of Biology, Washington University, St. Louis, MO 63130, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Nana Kusi
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Alexander Smith
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Swanne P. Gordon
- Department of Biology, Washington University, St. Louis, MO 63130, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Andrés López-Sepulcre
- Department of Biology, Washington University, St. Louis, MO 63130, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
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Richmond IC, Balluffi-Fry J, Vander Wal E, Leroux SJ, Rizzuto M, Heckford TR, Kennah JL, Riefesel GR, Wiersma YF. Individual snowshoe hares manage risk differently: integrating stoichiometric distribution models and foraging ecology. J Mammal 2021. [DOI: 10.1093/jmammal/gyab130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Herbivores making space use decisions must consider the trade-off between perceived predation risk and forage quality. Herbivores, specifically snowshoe hares (Lepus americanus), must constantly navigate landscapes that vary in predation risk and food quality, providing researchers with the opportunity to explore the factors that govern their foraging decisions. Herein, we tested predictions that intersect the risk allocation hypothesis (RAH) and optimal foraging theory (OFT) in a spatially explicit ecological stoichiometry framework to assess the trade-off between predation risk and forage quality. We used individual and population estimates of snowshoe hare (n = 29) space use derived from biotelemetry across three summers. We evaluated resource forage quality for lowbush blueberry (Vaccinium angustifolium), a common and readily available forage species within our system, using carbon:nitrogen and carbon:phosphorus ratios. We used habitat complexity to proxy perceived predation risk. We analyzed how forage quality of blueberry, perceived predation risk, and their interaction impact the intensity of herbivore space use. We used generalized mixed effects models, structured to enable us to make inferences at the population and individual home range level. We did not find support for RAH and OFT. However, variation in the individual-level reactions norms in our models showed that individual hares have unique responses to forage quality and perceived predation risk. Our finding of individual-level responses indicates that there is fine-scale decision-making by hares, although we did not identify the mechanism. Our approach illustrates spatially explicit empirical support for individual behavioral responses to the food quality–predation risk trade-off.
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Affiliation(s)
- Isabella C Richmond
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Juliana Balluffi-Fry
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Eric Vander Wal
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Shawn J Leroux
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Matteo Rizzuto
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Travis R Heckford
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Joanie L Kennah
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Gabrielle R Riefesel
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Yolanda F Wiersma
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
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Ito HC, Sasaki A. Evolutionary branching in distorted trait spaces. J Theor Biol 2020; 489:110152. [PMID: 31926206 DOI: 10.1016/j.jtbi.2020.110152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/29/2019] [Accepted: 01/03/2020] [Indexed: 11/19/2022]
Abstract
Biological communities are thought to have been evolving in trait spaces that are not only multi-dimensional, but also distorted in a sense that mutational covariance matrices among traits depend on the parental phenotypes of mutants. Such a distortion may affect diversifying evolution as well as directional evolution. In adaptive dynamics theory, diversifying evolution through ecological interaction is called evolutionary branching. This study analytically develops conditions for evolutionary branching in distorted trait spaces of arbitrary dimensions, by a local nonlinear coordinate transformation so that the mutational covariance matrix becomes locally constant in the neighborhood of a focal point. The developed evolutionary branching conditions can be affected by the distortion when mutational step sizes have significant magnitude difference among directions, i.e., the eigenvalues of the mutational covariance matrix have significant magnitude difference.
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Affiliation(s)
- Hiroshi C Ito
- Department of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies, SOKENDAI, Hayama, Kanagawa 240-0193, Japan.
| | - Akira Sasaki
- Department of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies, SOKENDAI, Hayama, Kanagawa 240-0193, Japan; Evolution and Ecology Program, International Institute for Applied Systems Analysis, Laxenburg, Austria
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Branco P, Egas M, Hall SR, Huisman J. Why Do Phytoplankton Evolve Large Size in Response to Grazing? Am Nat 2019; 195:E20-E37. [PMID: 31868537 DOI: 10.1086/706251] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Phytoplankton are among the smallest primary producers on Earth, yet they display a wide range of cell sizes. Typically, small phytoplankton species are stronger nutrient competitors than large phytoplankton species, but they are also more easily grazed. In contrast, evolution of large phytoplankton is often explained as a physical defense against grazing. Conceptually, this explanation is problematic, however, because zooplankton can coevolve larger size to counter this size-dependent escape from grazing. Here, we hypothesize that there is another advantage for the evolution of large phytoplankton size not so readily overcome: larger phytoplankton often provide lower nutritional quality for zooplankton. We investigate this hypothesis by analyzing an eco-evolutionary model that combines the ecological stoichiometry of phytoplankton-zooplankton interactions with coevolution of phytoplankton and zooplankton size. In our model, evolution of cell size modifies the nutrient uptake kinetics of phytoplankton according to known allometric relationships, which in turn affect the nutritional quality of phytoplankton. With this size-based mechanism, the model predicts that low grazing pressure or nonselective grazing by zooplankton favors evolution of small phytoplankton cells of high nutritional quality. In contrast, selective grazing for nutritious food favors evolution of large phytoplankton of low nutritional quality, which are preyed on by medium- to large-sized zooplankton. This size-dependent change in food quality may explain the commonly observed shift from dominance by small picophytoplankton in oligotrophic waters with low grazing pressure to large phytoplankton species in nutrient-rich waters with high grazing pressure.
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Leaf Nitrogen and Phosphorus Stoichiometry of Chinese fir Plantations across China: A Meta-Analysis. FORESTS 2019. [DOI: 10.3390/f10110945] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Leaf nitrogen (N) and phosphorus (P) stoichiometry at a large geographical scale is the result of long-term adaptation to the environment. Therefore, the patterns of leaf N and P spatial distributions and their controlling factors represent an important issue in current ecological research. To explore the leaf stoichiometry of Chinese fir at a national level, we conducted a meta-analysis based on the dataset of the leaf nitrogen (N) and phosphorus (P) concentrations and the N:P ratio from 28 study sites across China. For all of the age groups considered, the average concentrations of the leaf N and P concentrations and the N:P ratio were 11.94 mg g−1, 1.04 mg g−1, and 12.93, respectively. Significant differences were found in the leaf P concentration and N:P ratio between the five age groups, while the differences in the leaf N concentration between the groups were not significant. Linear fitting results indicated that the leaf P concentration decreased, and the leaf N:P ratio increased with the increase of the MAT (mean annual temperature) and soil N concentration. Redundancy analysis (RDA) revealed that the first axis, with an explanatory quantity of 0.350, indicated that the MAT (mean annual temperature), soil nitrogen concentration and stand age had a good relationship with the leaf P concentration and N:P ratio, while the second axis, with an explanatory quantity of 0.058, indicated that the leaf N concentration was less affected by the environmental factors. These results demonstrate that the leaf P concentration and N:P ratio are affected by the stand age, an uneven distribution of the heat and soil nutrient concentration status, and N, as the limiting element, remaining relatively stable. Overall, our findings revealed the response of leaf stoichiometric traits to environment change, which benefits the management of Chinese fir plantations.
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Ma W, Li J, Jimoh SO, Zhang Y, Guo F, Ding Y, Li X, Hou X. Stoichiometric ratios support plant adaption to grazing moderated by soil nutrients and root enzymes. PeerJ 2019; 7:e7047. [PMID: 31218124 PMCID: PMC6563791 DOI: 10.7717/peerj.7047] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/27/2019] [Indexed: 11/20/2022] Open
Abstract
Background Vegetation succession is one of the major driving processes of grassland degradation. Stoichiometry significantly contributes to vegetation dynamics. However, a knowledge gap exists in how soil nutrients and root enzymes influence the stoichiometric ratio to affect vegetation dynamics. Methods To address these questions, we selected a dominant species (Leymus chinensis (Trin.) Tzvel.) and a degraded-dominant species (Artemisia frigida Willd.) under different management regimes (enclosure and grazing) on the Inner Mongolia steppe. We measured (i) plant nutrient concentrations, (ii) root enzymes and (iii) soil nutrients to investigate how the selected plant species responded to grazing. Results The results show that: (i) N and P concentrations and the C:N:P ratio in different organs are significantly affected by grazing, and there is variation in the plant species' response. Grazing significantly increased N and P in the leaves and stems of L. chinensis and the stems and roots of A. frigida. (ii) Grazing significantly increased the activities of glutamine synthase but decreased the activities of acid phosphatase in L. chinensis. The nitrate reductase and acid phosphatase activities significantly increased in A. frigida under grazing conditions. (iii) Grazing decreased the total nitrogen, total phosphorus, and available nitrogen, but increased the available phosphorus in the soil. Conclusion We conclude that A. frigida is better adapted to grazing than L. chinensis, possibly because of its relatively increased stem and root growth, which enhance population expansion following grazing. Conversely, L. chinensis showed increased leaf and stem growth, but suffered nutrient and biomass loss as a result of excessive foraging by livestock, which severely affected its ability to colonize. Root enzymes coupled with soil nutrients can regulate plant nutrients and stoichiometric ratios as an adaptive response to grazing. Thus, we demonstrated that stoichiometric ratios allow species to better withstand grazing disturbances. This study provides a new understanding of the mechanisms involved in grazing-resistance within a plant-soil system.
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Affiliation(s)
- Wenjing Ma
- Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, Inner Mongolia, China
| | - Jin Li
- College of Grassland Science and Technology, China Agricultural University, Beijing, China
| | - Saheed Olaide Jimoh
- Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, Inner Mongolia, China
| | - Yujuan Zhang
- Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, Inner Mongolia, China
| | - Fenghui Guo
- Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, Inner Mongolia, China
| | - Yong Ding
- Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, Inner Mongolia, China.,Key Laboratory of Grassland Ecology and Restoration of Ministry of Agriculture, Hohhot, Inner Mongolia, China
| | - Xiliang Li
- Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, Inner Mongolia, China.,Key Laboratory of Grassland Ecology and Restoration of Ministry of Agriculture, Hohhot, Inner Mongolia, China
| | - Xiangyang Hou
- Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, Inner Mongolia, China.,Key Laboratory of Grassland Ecology and Restoration of Ministry of Agriculture, Hohhot, Inner Mongolia, China
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Koffel T, Daufresne T, Massol F, Klausmeier CA. Plant Strategies along Resource Gradients. Am Nat 2018; 192:360-378. [DOI: 10.1086/698600] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Branco P, Egas M, Elser JJ, Huisman J. Eco-Evolutionary Dynamics of Ecological Stoichiometry in Plankton Communities. Am Nat 2018; 192:E1-E20. [PMID: 29897797 DOI: 10.1086/697472] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Nitrogen (N) and phosphorus (P) limit primary production in many aquatic ecosystems, with major implications for ecological interactions in plankton communities. Yet it remains unclear how evolution may affect the N∶P stoichiometry of phytoplankton-zooplankton interactions. Here, we address this issue by analyzing an eco-evolutionary model of phytoplankton-zooplankton interactions with explicit nitrogen and phosphorus dynamics. In our model, investment of phytoplankton in nitrogen versus phosphorus uptake is an evolving trait, and zooplankton display selectivity for phytoplankton with N∶P ratios matching their nutritional requirements. We use this model to explore implications of the contrasting N∶P requirements of copepods versus cladocerans. The model predicts that selective zooplankton strongly affect the N∶P ratio of phytoplankton, resulting in deviations from their optimum N∶P ratio. Specifically, selective grazing by nitrogen-demanding copepods favors dominance of phytoplankton with low N∶P ratios, whereas phosphorus-demanding cladocerans favor dominance of phytoplankton with high N∶P ratios. Interestingly, selective grazing by nutritionally balanced zooplankton leads to the occurrence of alternative stable states, where phytoplankton may evolve either low, optimum, or high N∶P ratios, depending on the initial conditions. These results offer a new perspective on commonly observed differences in N∶P stoichiometry between plankton of freshwater and those of marine ecosystems and indicate that selective grazing by zooplankton can have a major impact on the stoichiometric composition of phytoplankton.
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10
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Tanioka T, Matsumoto K. Effects of incorporating age-specific traits of zooplankton into a marine ecosystem model. Ecol Modell 2018. [DOI: 10.1016/j.ecolmodel.2017.11.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Yamamichi M, Meunier CL, Peace A, Prater C, Rúa MA. Rapid evolution of a consumer stoichiometric trait destabilizes consumer-producer dynamics. OIKOS 2015. [DOI: 10.1111/oik.02388] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Masato Yamamichi
- Hakubi Center for Advanced Research/Center for Ecological Research, Kyoto Univ.; JP-606-8501 Kyoto Japan
| | - Cédric L. Meunier
- Dept of Ecology and Environmental Sciences; Umeå Univ.; SE-901 87 Umeå Sweden
| | - Angela Peace
- National Inst. for Mathematical and Biological Synthesis, Univ. of Tennessee; Knoxville TN 37996-3410 USA
| | - Clay Prater
- Environmental and Life Sciences, Trent Univ.; 1600 West Bank Drive Peterborough, ON K9J 7B8 Canada
| | - Megan A. Rúa
- Dept of Biology; Univ. of Mississippi; 214 Shoemaker Hall PO Box 1848, University MS 38677-1848 USA
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van Velzen E, Etienne RS. The importance of ecological costs for the evolution of plant defense against herbivory. J Theor Biol 2015; 372:89-99. [PMID: 25747775 DOI: 10.1016/j.jtbi.2015.02.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 02/11/2015] [Accepted: 02/24/2015] [Indexed: 11/17/2022]
Abstract
Plant defense against herbivory comes at a cost, which can be either direct (reducing resources available for growth and reproduction) or indirect (through reducing ecological performance, for example intraspecific competitiveness). While direct costs have been well studied in theoretical models, ecological costs have received almost no attention. In this study we compare models with a direct trade-off (reduced growth rate) to models with an ecological trade-off (reduced competitive ability), using a combination of adaptive dynamics and simulations. In addition, we study the dependence of the level of defense that can evolve on the type of defense (directly by reducing consumption, or indirectly by inducing herbivore mortality (toxicity)), and on the type of herbivore against which the plant is defending itself (generalists or specialists). We find three major results: First, for both direct and ecological costs, defense only evolves if the benefit to the plant is direct (through reducing consumption). Second, the type of cost has a major effect on the evolutionary dynamics: direct costs always lead to a single optimal strategy against herbivores, but ecological costs can lead to branching and the coexistence of non-defending and defending plants; however, coexistence is only possible when defending against generalist herbivores. Finally, we find that fast-growing plants invest less than slow-growing plants when defending against generalist herbivores, as predicted by the Resource Availability Hypothesis, but invest more than slow-growing plants when defending against specialists. Our results clearly show that assumptions about ecological interactions are crucial for understanding the evolution of defense against herbivores.
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Affiliation(s)
- Ellen van Velzen
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, PO Box 11103, 9700 CC Groningen, The Netherlands.
| | - Rampal S Etienne
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, PO Box 11103, 9700 CC Groningen, The Netherlands.
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Allgeier JE, Layman CA, Mumby PJ, Rosemond AD. Consistent nutrient storage and supply mediated by diverse fish communities in coral reef ecosystems. GLOBAL CHANGE BIOLOGY 2014; 20:2459-2472. [PMID: 24692262 DOI: 10.1111/gcb.12566] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 06/03/2023]
Abstract
Corals thrive in low nutrient environments and the conservation of these globally imperiled ecosystems is largely dependent on mitigating the effects of anthropogenic nutrient enrichment. However, to better understand the implications of anthropogenic nutrients requires a heightened understanding of baseline nutrient dynamics within these ecosystems. Here, we provide a novel perspective on coral reef nutrient dynamics by examining the role of fish communities in the supply and storage of nitrogen (N) and phosphorus (P). We quantified fish-mediated nutrient storage and supply for 144 species and modeled these data onto 172 fish communities (71 729 individual fish), in four types of coral reefs, as well as seagrass and mangrove ecosystems, throughout the Northern Antilles. Fish communities supplied and stored large quantities of nutrients, with rates varying among ecosystem types. The size structure and diversity of the fish communities best predicted N and P supply and storage and N : P supply, suggesting that alterations to fish communities (e.g., overfishing) will have important implications for nutrient dynamics in these systems. The stoichiometric ratio (N : P) for storage in fish mass (~8 : 1) and supply (~20 : 1) was notably consistent across the four coral reef types (but not seagrass or mangrove ecosystems). Published nutrient enrichment studies on corals show that deviations from this N : P supply ratio may be associated with poor coral fitness, providing qualitative support for the hypothesis that corals and their symbionts may be adapted to specific ratios of nutrient supply. Consumer nutrient stoichiometry provides a baseline from which to better understand nutrient dynamics in coral reef and other coastal ecosystems, information that is greatly needed if we are to implement more effective measures to ensure the future health of the world's oceans.
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Affiliation(s)
- Jacob E Allgeier
- Odum School of Ecology, University of Georgia, Athens, Georgia, USA
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Mellard JP, Ballantyne F. Conflict between dynamical and evolutionary stability in simple ecosystems. THEOR ECOL-NETH 2014. [DOI: 10.1007/s12080-014-0217-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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van Velzen E, Etienne RS. The evolution and coexistence of generalist and specialist herbivores under between-plant competition. THEOR ECOL-NETH 2012. [DOI: 10.1007/s12080-012-0162-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Chatterjee S. Coupling effect of grazing pressure and nutrient enrichment on system stability. Math Biosci 2012; 238:1-11. [PMID: 22554498 DOI: 10.1016/j.mbs.2012.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 04/08/2012] [Accepted: 04/11/2012] [Indexed: 11/17/2022]
Abstract
A three dimensional nutrient-plant-herbivore model was proposed and conditions for boundedness, positive invariance, existence and stability of different equilibrium points, Hopf-bifurcation and global stability were obtained. We performed numerical simulations to observe the simultaneous effect of the top-down and the bottom-up mechanism on the system. It was found that nutrient enrichment destroyed the coexistence steady state of the system. This nutrient enrichment could be due to high nutrient input rate or high nutrient recycling rate. In both cases the system showed instability. Moreover, these results were independent of the grazing pressure and the predation functional form.
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Affiliation(s)
- Samrat Chatterjee
- Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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