Secondary Production within a Seagrass Bed (Zostera marina and Ruppia maritima) in Lower Chesapeake Bay

Fredette, Thomas J.; Díaz, Robert J.

doi:10.2307/1351787

Cited by 87 publications

(47 citation statements)

References 18 publications

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“…In polyhaline regions of the Bay deeper than 0.5 m, these beds are dominated by eelgrass (Orth and Moore 1988), one of the most widespread and abundant marine plants in the northern hemisphere (Stevenson 1988). Eelgrass supports a highly productive and economically important community, providing habitat for fast-growing epiphytic algae, small invertebrate grazers, waterfowl, and commercially important fish and shellfish (Penhale 1977, Heck and Thoman 1984, Thayer et al 1984, Fredette et al 1990). Most of the resident grazing invertebrates appear to be generalist epiphyte and detritus feeders van Montfrans 1984, Jernakoff et al 1996).…”

Section: Natural History Of the Systemmentioning

confidence: 99%

“…Stocking the remaining four blocks of mesocosms with eelgrass and grazers was completed by 24 April. To ensure that treatment effects were attributable to differences in grazer diversity and species composition, rather than differences in initial grazer biomass, we initiated the experiment with the same total estimated grazer biomass (ϳ0.35 g ash-free dry mass [AFDM]) in each treatment; this biomass is well within the range found in Chesapeake Bay eelgrass beds in spring (Fredette et al 1990). The number of grazers corresponding to 0.35 g AFDM was 115 for Gammarus, 33 for Idotea, and 91 for Erichsonella; mixed-species treatments used fractions of these numbers to achieve a total estimated grazer biomass of 0.35 g. Each experimental container was harvested ϳ6 wk after eelgrass planting.…”

Section: Experimental Designmentioning

confidence: 99%

See 1 more Smart Citation

Grazer Diversity, Functional Redundancy, and Productivity in Seagrass Beds: An Experimental Test

Duffy

Macdonald

Rhode

et al. 2001

Ecology

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Abstract. Concern over the accelerating loss of biodiversity has stimulated renewed interest in relationships among species richness, species composition, and the functional properties of ecosystems. Mechanistically, the degree of functional differentiation or complementarity among individual species determines the form of such relationships and is thus important to distinguishing among alternative hypotheses for the effects of diversity on ecosystem processes. Although a growing number of studies have reported relationships between plant diversity and ecosystem processes, few have explicitly addressed how functional diversity at higher trophic levels influences ecosystem processes. We used mesocosm experiments to test the impacts of three herbivorous crustacean species (Gammarus mucronatus, Idotea baltica, and Erichsonella attenuata) on plant biomass accumulation, relative dominance of plant functional groups, and herbivore secondary production in beds of eelgrass (Zostera marina), a dominant feature of naturally low-diversity estuaries throughout the northern hemisphere. By establishing treatments with all possible combinations of the three grazer species, we tested the degree of functional redundancy among grazers and their relative impacts on productivity.Grazer species composition strongly influenced eelgrass biomass accumulation and grazer secondary production, whereas none of the processes we studied was clearly related to grazer species richness over the narrow range (0-3 species) studied. In fact, all three measured ecosystem processes-epiphyte grazing, and eelgrass and grazer biomass accumulation-reached highest values in particular single-species treatments. Experimental deletions of individual species from the otherwise-intact assemblage confirmed that the three grazer species were functionally redundant in impacting epiphyte accumulation, whereas secondary production was sensitive to deletion of G. mucronatus, indicating its unique, nonredundant role in influencing this variable. In the field, seasonal abundance patterns differed markedly among the dominant grazer species, suggesting that complementary grazer phenologies may reduce total variance in grazing pressure on an annual basis. Our results show that even superficially similar grazer species can differ in both sign and magnitude of impacts on ecosystem processes and emphasize that one must be cautious in assuming redundancy when assigning species to functional groups.

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Section: Natural History Of the Systemmentioning

confidence: 99%

Section: Experimental Designmentioning

confidence: 99%

Grazer Diversity, Functional Redundancy, and Productivity in Seagrass Beds: An Experimental Test

Duffy

Macdonald

Rhode

et al. 2001

Ecology

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“…They have been receiving increasing attention worldwide since the 1970s because of recognition of (1) their mul-'E-mail: jjorth@vims.edu "The order of the 2 primary authors was assigned based on contribution to the manuscript. The remaining authors are arranged alphabetically tiple ecological functions in estuarine and coastal systems, such as nursery and fish habitat (Coles et al 1987, Heck et al 1997) and regions of high primary and secondary production (Larkum et al 1989, Edgar 1990, Fredette et al 1990, and (2) losses in many areas of the world due to anthropogenic inputs of nutrients and sediments (Short & Burdick 1996, Short & WyllieEcheverria 1996. In addition, considerable seagrass area has been permanently lost to coastal development, primarily from dredge and fill operations (Short et al 1991) or altered due to commercial/recreational activities such as propeller and anchor scarring (Walker et al 1989, Sargent et al 1995, Dawes et al 1997.…”

Section: Introductionmentioning

confidence: 99%

A review of issues in seagrass seed dormancy and germination:implications for conservation and restoration

Orth¹,

Harwell²,

Bailey³

et al. 2000

Mar. Ecol. Prog. Ser.

183

116

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Seagrasses have received considerable attention over the past 2 decades because of the multiple ecological roles they play in estuarine and coastal ecosystems and concerns over worldwide losses of seagrass habitat due to direct and indirect human impacts. Restoration and conservation efforts are underway in some areas of the world, but progress may be limited by the paucity of information on the role of seeds in bed dynamics. Although flowering occurs in most of the 58 seagrass species, seed germination data exist for only 19 of the 42 species that have some period of dormancy, with only 93 published references to field and/or laboratory studies. This review addresses critical issues in conservation and restoration of seagrasses involving seed dormancy (e.g. environmental vs physiological), existence and type of seed bank (transient or persistent), and factors influencing seed germination (e.g. salinity, temperature, light). Results of many earlier published studies relating seed germination to various environmental factors may need re-examination given more recent published data which show a confounding influence of oxygen level on the germination process. We highlight the importance of conducting ecologically meaningful germination studies, including germination experiments conducted in sediments. We also identify questions for future research that may figure prominently in landscape level questions regarding protected marine or estuarine reserves, habitat fragmentation, and restoration.

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“…Eelgrasses, in particular, have a great capacity to provide food resources, substrate and shelter to many taxonomic groups (Fredette et al 1990;Boström and Mattila 1999;Hasegawa et al 2008). Recent sampling of peracarid crustaceans in Spanish seagrass habitats (Esquete et al 2011) found several species of the asellotan isopod family Munnidae.…”

Section: Introductionmentioning

confidence: 99%

Ecology and systematics of a new species of Uromunna (Crustacea: Isopoda) from Spanish eelgrass beds

2014

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Uromunna naherba sp. nov. is described from eelgrass beds (Zostera marina and Z. noltii) of the NW Iberian Peninsula. This is the second species of the genus reported from the NE Atlantic, after U. petiti. The new species was more abundant on rhizomes than on the leaves of the plants. Seasonal samples show that ovigerous females are present throughout the year, but become more abundant in late spring and summer, when adult males decrease in frequency. Ovigerous females appear in only one size class. Owing to the yearly productivity cycle of the eelgrasses, these data suggest that the species is semelparous and completes its lifecycle within 1 year. The taxonomic characters of the genus are discussed.

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Secondary Production within a Seagrass Bed (Zostera marina and Ruppia maritima) in Lower Chesapeake Bay

Cited by 87 publications

References 18 publications

Grazer Diversity, Functional Redundancy, and Productivity in Seagrass Beds: An Experimental Test

Grazer Diversity, Functional Redundancy, and Productivity in Seagrass Beds: An Experimental Test

A review of issues in seagrass seed dormancy and germination:implications for conservation and restoration

Ecology and systematics of a new species of Uromunna (Crustacea: Isopoda) from Spanish eelgrass beds

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