A trophic cascade regulates salt marsh primary production

Silliman, Brian R.; Bertness, Mark D.

doi:10.1073/pnas.162366599

Cited by 441 publications

(332 citation statements)

References 25 publications

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“…Orchelimum was negatively correlated with Littoraria, likely because the snails wound plants and promote invasion by ascomycete decomposers, hastening plant death (Silliman and Zieman 2001;Silliman and Bertness 2002;Silliman and Newell 2003). Thus, it is possible that Littoraria competes with Orchelimum for Spartina.…”

Section: Herbivore Density and Food Selectionmentioning

confidence: 99%

Impact of Fertilization on a Salt Marsh Food Web in Georgia

McFarlin

Brewer

Buck

et al. 2008

Estuaries and Coasts: J CERF

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We examined the response of a salt marsh food web to increases in nutrients at 19 coastal sites in Georgia. Fertilization increased the nitrogen content of the two dominant plants, Spartina alterniflora and Juncus roemerianus, indicating that added nutrients were available to and taken up by both species. Fertilization increased Spartina cover, height, and biomass and Juncus height, but led to decreases in Juncus cover and biomass. Fertilization increased abundances of herbivores (grasshoppers) and herbivore damage, but had little effect on decomposers (fungi), and no effect on detritivores (snails). In the laboratory, herbivores and detritivores did not show a feeding preference for fertilized versus control plants of either species, nor did detritivores grow more rapidly on fertilized versus control plants, suggesting that changes in herbivore abundance in the field were driven more by plant size or appearance than by plant nutritional quality.Community patterns in control plots varied predictably among sites (i.e., 17 of 20 regression models examining variation in biological variables across sites were significant), but variation in the effects of fertilization across sites could not be easily predicted (i.e., only 6 of 20 models were significant). Natural variation among sites was typically similar or greater than impacts of fertilization when both were assessed using the coefficient of variation. Overall, these results suggest that eutrophication of salt marshes is likely to have stronger impacts on plants and herbivores than on decomposers and detritivores, and that impacts at any particular site might be hard to distinguish from natural variation among sites.

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Section: Herbivore Density and Food Selectionmentioning

confidence: 99%

Impact of Fertilization on a Salt Marsh Food Web in Georgia

McFarlin

Brewer

Buck

et al. 2008

Estuaries and Coasts: J CERF

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“…Trophic cascades indirectly maintain many important basal species including hardwood trees, kelps, salt-marsh plants, and scallops (Estes and Palmisano 1974;Myers et al 2007;Ripple and Beschta 2007;Silliman and Bertness 2002) when top predators reduce the foraging of intermediate consumers, either by eating them (Carpenter et al 1985;Hairston et al 1960;Paine 1980) or by altering their behavior (Abrams 1995;Preisser et al 2005;Trussell et al 2002). Although trophic cascades require that top predators be present, predator presence-alone-may not always be suYcient (Schmitz et al 2004;Werner and Peacor 2003).…”

Section: Introductionmentioning

confidence: 99%

Invasive species cause large-scale loss of native California oyster habitat by disrupting trophic cascades

et al. 2009

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Although invasive species often resemble their native counterparts, diVerences in their foraging and antipredator strategies may disrupt native food webs. In a California estuary, we showed that regions dominated by native crabs and native whelks have low mortality of native oysters (the basal prey), while regions dominated by invasive crabs and invasive whelks have high oyster mortality and are consequently losing a biologically diverse habitat.Using Weld experiments, we demonstrated that the invasive whelk's distribution is causally related to a large-scale pattern of oyster mortality. To determine whether predatorprey interactions between crabs (top predators) and whelks (intermediate consumers) indirectly control the pattern of oyster mortality, we manipulated the presence and invasion status of the intermediate and top trophic levels in laboratory mesocosms. Our results show that native crabs indirectly maintain a portion of the estuary's oyster habitat by both consuming native whelks (density-mediated trophic cascade) and altering their foraging behavior (trait-mediated trophic cascade). In contrast, invasive whelks are naive to crab predators and fail to avoid them, thereby inhibiting trait-mediated cascades and their invasion into areas with native crabs. Similarly, when native crabs are replaced with invasive crabs, the naive foraging strategy and smaller size of invasive crabs prevents them from eYciently consuming adult whelks, thereby inhibiting strong density-mediated cascades. Thus, while trophic cascades allow native crabs, whelks, and oysters to locally co-exist, the replacement of native crabs and whelks by functionally similar invasive species results in severe depletion of native oysters. As 123 coastal systems become increasingly invaded, the mismatch of evolutionarily based strategies among predators and prey may lead to further losses of critical habitat that support marine biodiversity and ecosystem function.

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“…Littoraria can exert significant top-down control on Spartina production through grazing (Silliman and Zieman, 2001;Silliman and Bertness, 2002). Littoraria populations can be food-and habitat-limited (Stiven and Kuenzler, 1979), although predation, primarily by the blue crab, Callinectes sapidus, can also be important in structuring them (Hamilton, 1976;Schindler et al, 1994).…”

Section: Tidal Saltwater Marshesmentioning

confidence: 99%