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Novak M. High variation in handling times confers 35-year stability to predator feeding rates despite community change. Ecology 2023; 104:e3954. [PMID: 36495236 DOI: 10.1002/ecy.3954] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 09/15/2022] [Accepted: 11/07/2022] [Indexed: 12/14/2022]
Abstract
Historical resurveys of ecological communities are important for placing the structure of modern ecosystems in context. Rarely, however, are snapshot surveys alone sufficient for providing direct insight into the rates of the ecological processes underlying community functioning, either now or in the past. In this study, I used a statistically reasoned observational approach to estimate the feeding rates of a New Zealand intertidal predator, Haustrum haustorium, using diet surveys performed at several sites by Robert Paine in 1968-1969 and by me in 2004. Comparisons between time periods reveal a remarkable consistency in the predator's prey-specific feeding rates, which contrasts with the changes I observed in prey abundances, the predator's body-size distribution, and the prey's proportional contributions to the predator's apparent diet. Although these and additional changes in the predator's per-capita attack rates seem to show adaptive changes in its prey preferences, they do not. Rather, feeding-rate stability is an inherently statistical consequence of the predator's high among-prey variation in handling times which determine the length of time that feeding events will remain detectable to observers performing diet surveys. Though understudied, similarly high among-prey variation in handling (or digestion) times is evident in many predator species throughout the animal kingdom. The resultant disconnect between a predator's apparent diet and its actual feeding rates suggests that much of the temporal, biogeographic, and seemingly context-dependent variation that is often perceived in community structure, predator diets, and food-web topology may be of less functional consequence than assumed. Qualitative changes in ecological pattern need not represent qualitative changes in ecological process.
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Affiliation(s)
- Mark Novak
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, USA
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Preston DL, Falke LP, Henderson JS, Novak M. Food-web interaction strength distributions are conserved by greater variation between than within predator-prey pairs. Ecology 2019; 100:e02816. [PMID: 31287561 DOI: 10.1002/ecy.2816] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 04/10/2019] [Accepted: 06/10/2019] [Indexed: 12/25/2022]
Abstract
Species interactions in food webs are usually recognized as dynamic, varying across species, space, and time because of biotic and abiotic drivers. Yet food webs also show emergent properties that appear consistent, such as a skewed frequency distribution of interaction strengths (many weak, few strong). Reconciling these two properties requires an understanding of the variation in pairwise interaction strengths and its underlying mechanisms. We estimated stream sculpin feeding rates in three seasons at nine sites in Oregon to examine variation in trophic interaction strengths both across and within predator-prey pairs. Predator and prey densities, prey body mass, and abiotic factors were considered as putative drivers of within-pair variation over space and time. We hypothesized that consistently skewed interaction strength distributions could result if individual interaction strengths show relatively little variation, or alternatively, if interaction strengths vary but shift in ways that conserve their overall frequency distribution. Feeding rate distributions remained consistently and positively skewed across all sites and seasons. The mean coefficient of variation in feeding rates within each of 25 focal species pairs across surveys was less than half the mean coefficient of variation seen across species pairs within a survey. The rank order of feeding rates also remained conserved across streams, seasons and individual surveys. On average, feeding rates on each prey taxon nonetheless varied by a hundredfold, with some feeding rates showing more variation in space and others in time. In general, feeding rates increased with prey density and decreased with high stream flows and low water temperatures, although for nearly half of all species pairs, factors other than prey density explained the most variation. Our findings show that although individual interaction strengths exhibit considerable variation in space and time, they can nonetheless remain relatively consistent, and thus predictable, compared to the even larger variation that occurs across species pairs. These results highlight how the ecological scale of inference can strongly shape conclusions about interaction strength consistency and help reconcile how the skewed nature of interaction strength distributions can persist in highly dynamic food webs.
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Affiliation(s)
- Daniel L Preston
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Landon P Falke
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Jeremy S Henderson
- Oregon Department of Fish and Wildlife, 305 North Canyon Boulevard, Canyon City, Oregon, 97820, USA
| | - Mark Novak
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, 97330, USA
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Wright JM, O’Connor WA, Parker LM, Ross PM. Predation by the endemic whelk Tenguella marginalba (Blainville, 1832) on the invasive Pacific oyster Crassostrea gigas (Thunberg, 1793). MOLLUSCAN RESEARCH 2018. [DOI: 10.1080/13235818.2017.1420397] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- John M. Wright
- School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - Wayne A. O’Connor
- NSW Department of Primary Industries, Port Stephens Fisheries Institute, Taylors Beach, Australia
| | - Laura M. Parker
- School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - Pauline M. Ross
- School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
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McWilliam RA, Minchinton TE, Ayre DJ. Despite prolonged association in closed populations, an intertidal predator does not prefer abundant local prey to novel prey. Biol J Linn Soc Lond 2013. [DOI: 10.1111/bij.12007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Russell A. McWilliam
- Institute for Conservation Biology and Environmental Management; School of Biological Sciences; University of Wollongong; Wollongong; NSW; 2522; Australia
| | - Todd E. Minchinton
- Institute for Conservation Biology and Environmental Management; School of Biological Sciences; University of Wollongong; Wollongong; NSW; 2522; Australia
| | - David J. Ayre
- Institute for Conservation Biology and Environmental Management; School of Biological Sciences; University of Wollongong; Wollongong; NSW; 2522; Australia
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COULSON LAURAA, PERRIN CECILE, ROBERTS DAVIDG, MINCHINTON TODDE, AYRE DAVIDJ. Can limited dispersal or biotic interaction explain the declining abundance of the whelk, Morula marginalba, at the edge of its range? Biol J Linn Soc Lond 2011. [DOI: 10.1111/j.1095-8312.2011.01676.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Petraitis PS, Methratta ET, Rhile EC, Vidargas NA, Dudgeon SR. Experimental confirmation of multiple community states in a marine ecosystem. Oecologia 2009; 161:139-48. [PMID: 19399520 PMCID: PMC2779835 DOI: 10.1007/s00442-009-1350-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 04/01/2009] [Indexed: 11/25/2022]
Abstract
Small changes in environmental conditions can unexpectedly tip an ecosystem from one community type to another, and these often irreversible shifts have been observed in semi-arid grasslands, freshwater lakes and ponds, coral reefs, and kelp forests. A commonly accepted explanation is that these ecosystems contain multiple stable points, but experimental tests confirming multiple stable states have proven elusive. Here we present a novel approach and show that mussel beds and rockweed stands are multiple stable states on intertidal shores in the Gulf of Maine, USA. Using broad-scale observational data and long-term data from experimental clearings, we show that the removal of rockweed by winter ice scour can tip persistent rockweed stands to mussel beds. The observational data were analyzed with Anderson's discriminant analysis of principal coordinates, which provided an objective function to separate mussel beds from rockweed stands. The function was then applied to 55 experimental plots, which had been established in rockweed stands in 1996. Based on 2005 data, all uncleared controls and all but one of the small clearings were classified as rockweed stands; 37% of the large clearings were classified as mussel beds. Our results address the establishment of mussels versus rockweeds and complement rather than refute the current paradigm that mussel beds and rockweed stands, once established, are maintained by site-specific differences in strong consumer control.
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Affiliation(s)
- Peter S Petraitis
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA.
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Novak M, Wootton JT. Estimating nonlinear interaction strengths: an observation-based method for species-rich food webs. Ecology 2008; 89:2083-9. [PMID: 18724718 DOI: 10.1890/08-0033.1] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Efforts to estimate the strength of species interactions in species-rich, reticulate food webs have been hampered by the multitude of direct and indirect interactions such systems exhibit and have been limited by an assumption that pairwise interactions display linear functional forms. Here we present a new method for directly measuring, on a per capita basis, the nonlinear strength of trophic species interactions within such food webs. This is an observation-based method, requiring three pieces of information: (1) species abundances, (2) predator and prey-specific handling times, and (3) data from predator-specific feeding surveys in which the number of individuals observed feeding on each of the predator's prey species has been tallied. The method offers a straightforward way to assess the completeness of one's sampling effort in accurately estimating interaction strengths through the construction of predator-specific prey accumulation curves. The method should be applicable to a variety of systems in which empirical estimates of direct interaction strengths have thus far remained elusive.
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Affiliation(s)
- Mark Novak
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois 60637, USA.
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JACKSON AC, CHAPMAN MG, UNDERWOOD AJ. Ecological interactions in the provision of habitat by urban development: whelks and engineering by oysters on artificial seawalls. AUSTRAL ECOL 2008. [DOI: 10.1111/j.1442-9993.2007.01818.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Navarrete SA, Menge BA, Daley BA. SPECIES INTERACTIONS IN INTERTIDAL FOOD WEBS: PREY OR PREDATION REGULATION OF INTERMEDIATE PREDATORS? Ecology 2000. [DOI: 10.1890/0012-9658(2000)081[2264:siiifw]2.0.co;2] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Underwood AJ. Experimental ecology of rocky intertidal habitats: what are we learning? JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY 2000; 250:51-76. [PMID: 10969163 DOI: 10.1016/s0022-0981(00)00179-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Experimental analyses of causes of patterns of distribution and abundance of intertidal animals and plants on rocky shores have been a major activity for many years. In this review, some of the themes and topics that have emerged from such analyses are briefly discussed to provide an up-date for practitioners and ecologists working in other habitats. Conceptual issues include the widespread occurrence of transphyletic use of the same resources (space and food), theories and experimental analyses of intermediate disturbance in relation to numbers of species, the complex but pervasive nature of indirect interactions among species, relative importance of 'top-down' versus 'bottom-up' control of assemblages and the importance to rocky intertidal species of 'supply-side' influences on densities and interactions. Methodological advances include experimental designs for complex and patchy, interacting sets of species, the importance of controls in experimental manipulations and methods for analyses of hierarchical scales of patterns and processes. Finally, some contributions to social issues (pollution, biodiversity) and some scenarios for future directions are briefly considered.
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Affiliation(s)
- AJ Underwood
- Centre for Research on Ecological Impacts of Coastal Cities, Marine Ecology Laboratories A11, University of Sydney, NSW 2006, Sydney, Australia
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Rovero F, Hughes RN, Chelazzi G. Effect of experience on predatory behaviour of dogwhelks. Anim Behav 1999; 57:1241-1249. [PMID: 10373257 DOI: 10.1006/anbe.1999.1102] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We used an acoustic transducer to monitor the radular activity of dogwhelks, Nucella lapillus, drilling mussels, Mytilus edulis, in the laboratory and we examined the effect of dietary experience on prey-handling behaviour. For the first time, phases of inspection, penetration and ingestion could be distinguished directly, and consequently the prey-handling process analysed in detail. Dogwhelks with different field-based experience of mussels showed different handling behaviour. Those collected from a mussel-dominated shore more readily adopted the faster method of penetrating between the slightly gaping valves, instead of the slower method of drilling through the shell. Those collected from a barnacle-dominated shore took significantly longer to attack the mussel and then were unable to switch from drilling to penetrating through the gape between valves. Experience of specific prey in the field, by reducing handling time, could promote fitness by reducing exposure to environmental hazards. Laboratory attempts to train dogwhelks from the barnacle-dominated shore to use the gape penetration method failed, suggesting that functional constraints, such as injection of a relaxant when penetrating through the gape and/or genetically controlled behavioural traits, could limit the ability to learn handling skills. Copyright 1999 The Association for the Study of Animal Behaviour.
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Affiliation(s)
- F Rovero
- School of Biological Sciences, University of Wales
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Sr Vadas RL, Burrows MT, Hughes RN. Foraging strategies of dogwhelks, Nucella lapillus (L.): interacting effects of age, diet and chemical cues to the threat of predation. Oecologia 1994; 100:439-450. [PMID: 28306933 DOI: 10.1007/bf00317866] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/1993] [Accepted: 08/23/1994] [Indexed: 11/29/2022]
Affiliation(s)
- R L Sr Vadas
- School of Biological Sciences, University of Wales, LL57 2UW, Bangor, Gwynedd, Wales UK
| | - M T Burrows
- Dunstaffnage Marine Laboratory, P.O. Box 3, PA34 4AD, Oban, Argyll, Scotland, UK
| | - R N Hughes
- Dunstaffnage Marine Laboratory, P.O. Box 3, PA34 4AD, Oban, Argyll, Scotland, UK
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Generalizing from experiments: is predation strong or weak in the New England rocky intertidal? Oecologia 1991; 88:1-8. [DOI: 10.1007/bf00328396] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/1990] [Accepted: 05/10/1991] [Indexed: 11/25/2022]
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Petraitis PS. Direct and indirect effects of predation, herbivory and surface rugosity on mussel recruitment. Oecologia 1990; 83:405-413. [DOI: 10.1007/bf00317568] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/1989] [Accepted: 02/16/1990] [Indexed: 11/29/2022]
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16
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Menge B, Farrell T. Community Structure and Interaction Webs in Shallow Marine Hard-Bottom Communities: Tests of an Environmental Stress Model. ADV ECOL RES 1989. [DOI: 10.1016/s0065-2504(08)60159-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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FAIRWEATHER PETERG. Predation creates haloes of bare space among prey on rocky seashores in New South Wales. AUSTRAL ECOL 1988. [DOI: 10.1111/j.1442-9993.1988.tb00988.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Rittschof D, Gruber G. Response to Prey Odors by Oyster Drills,Urosalpinx cinerea cinerea, Urosalpinx cinerea follyensisandEupleura caudata etterae. ACTA ACUST UNITED AC 1988. [DOI: 10.1080/10236248809378672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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A test of the Menge-Sutherland model of community organization in a tropical rocky intertidal food web. Oecologia 1986; 71:75-89. [PMID: 28312087 DOI: 10.1007/bf00377324] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/1986] [Indexed: 10/26/2022]
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