Processing of allochthonous macrophyte subsidies by sandy beach consumers: estimates of feeding rates and impacts on food resources

Lastra, Mariano; Page, Henry M.; Dugan, Jenifer E.; Hubbard, David M.; Rodil, Iván F.

doi:10.1007/s00227-008-0913-3

Cited by 137 publications

(124 citation statements)

References 43 publications

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“…Coverage was measured using the line intercept method (Dugan et al 2003). All wrack present on the sand surface within a 1 m wide strip of beach along each transect was collected to assess specific composition and biomass (Lastra et al 2008).…”

Section: Methodsmentioning

confidence: 99%

Annual cycle of wrack supply to sandy beaches: effect of the physical environment

Barreiro¹,

Gómez²,

Lastra³

et al. 2011

Mar. Ecol. Prog. Ser.

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Connectivity between ecosystems has been widely recognised as an important issue in ecological studies. Sandy beaches are very dynamic and open ecosystems, mainly supported by allochthonous subsidies of stranded organic matter (mostly macroalgae), also termed wrack supply. The magnitude and composition of algal wrack biomass throughout the annual cycle was assessed for 6 sandy beaches on the Galician coast, NW Spain. The effect of wave action and the topographical features of each beach in the wrack deposition process were investigated. Wrack species composition, biomass and coverage were measured monthly along 6 transects at each beach. Mean dry weight of wrack fluctuated from 14 ± 5.3 to 9189 ± 3594 g m -1 (along transects) between locations. Wrack was predominantly composed of brown algae, which accounted for 70% of the average biomass year round; the dominant species were Cystoseira sp. (30.3 ± 17.4%) and Sargassum muticum (14.2 ± 7.1%). A cyclical pattern in wrack composition, coupled with the life cycle of the predominant macroalgae, was observed. Wrack biomass and species composition were mostly explained by wave height and the ratio of beach length to beach area. Small, wave-sheltered beaches received the largest inputs of wrack, and had the lowest relative contribution of brown algae. These results provide evidence that variability in wrack supply on sandy beaches can be explained through interactions between wave exposure, coastal topography and seasonality.

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Section: Methodsmentioning

confidence: 99%

Annual cycle of wrack supply to sandy beaches: effect of the physical environment

Barreiro¹,

Gómez²,

Lastra³

et al. 2011

Mar. Ecol. Prog. Ser.

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“…One of the most important ecological roles of the invertebrates (as primary consumers) inhabiting sandy shores is the fragmentation and decomposition of beach-cast wrack as sources of energy and nutrients (organic matter) (Catenazzi and Donnelly, 2007;Colombini et al, 2003;Lastra et al, 2008;Salathé and Riera, 2012). In addition, the availability of wrack would influence the structure of these primary consumers (mainly crustaceans), which in turn supports the growth of consumers in higher trophic levels (e.g.…”

Section: Introductionmentioning

confidence: 99%

Niche segregation amongst sympatric species at exposed sandy shores with contrasting wrack availabilities illustrated by stable isotopic analysis

Bessa

Baeta

Marques

2014

Ecological Indicators

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a b s t r a c tWrack supplies (macroalgae, seagrasses and carrion) are a common feature of sandy beaches worldwide. These allochthonous inputs are a potential high-quality food subsidy for beach fauna, but little is known about the feeding ecology and niche segregation strategies of these species in beaches with limited wrack availabilities. We used stable isotopic ratios of nitrogen and carbon to examine the diets and niche segregation among three sympatric crustaceans, the amphipods Talitrus saltator and Talorchestia brito, and the isopod Tylos europaeus, in two temperate beaches, Cabedelo and Quiaios, on the Portuguese Atlantic coast, with contrasting wrack availabilities, over winter and summer. In the beach with limited wrack (Quiaios), consumers showed significantly different interspecific and temporal isotopic signatures, suggesting a distinct foraging habitat and niche differentiation. Mixing models outputs (SIAR) revealed in this case a seasonal shift in the diet of consumers from terrestrial sources in winter towards marinebased sources (phytoplankton) in the summer. In contrast, at Cabedelo, consumers showed clear overlap in isotopic signatures, with similar contributions of the available wrack to their diets. As a whole, an opportunistic and generalist feeding behaviour was described for these species, namely for T. saltator. Isotopic profiles support the occurrence of spatial overlap during summer but different foraging strategies of the three species in these beaches during winter. Our results show that on temperate beaches with ephemeral wrack supplies, consumers might need to adopt different foraging strategies and niche segregation for their subsistence, and additionally illustrate the viability of using stable isotopes to capture subtle changes in trophic niches.

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“…Thus, our results lead to the conclusion that food quality significantly counteracts the deleterious effects of UVR on FCR of amphipod males. As we mentioned above, high quality food enhances fitness, as for example shown by Lastra et al (2008) for the talitrid amphipod Megalorchestia corniculata that reached the highest growth rates when fed on high quality food. Also, CruzRivera and Hay (2000) showed that Gammarus mucronatus grew larger and produced more gonads when feeding on high quality food.…”

Section: Discussionmentioning

confidence: 72%

Combined impact of ultraviolet radiation and increased nutrients supply: a test of the potential anthropogenic impacts on the benthic amphipod Amphitoe valida from Patagonian waters (Argentina)

Valiñas¹,

Bermejo²,

Galbán³

et al. 2014

Front. Environ. Sci.

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Experiments were conducted during the Austral Summer of 2014 to determine the effects of increased nutrient input and ultraviolet radiation (UVR) on the food consumption rate (FCR) and food preference in the amphipod Amphitoe valida. We collected specimens from the Patagonian coast (Argentina), from beaches close (Barrancas Blancas; BB) and further away (Cangrejales; C) from the Chubut River, which constitutes the potential source of eutrophication. Organisms were exposed to different radiation regimes (full radiation vs. PAR only) and fed with different macroalgae diets (i.e., from different geographical location and with different quality in terms on nutrient content). Males collected from C showed food compensation, consuming more food under low-nutrient diets, while no compensation was observed in males from BB. Regardless of their origin, UVR decreased the FCR when males where fed on ambient nutrient diets, but not when males fed on high-quality diets indicating that in the former case, individuals were in worse physiological conditions to cope with UVR; food quality, however, significantly counteracted the deleterious effects of UVR on FCR. Females collected from the two beaches showed similar FCR under high-nutrient diet and had no food compensation when fed in low-nutrient diets. Females were more vulnerable to UVR, since their FCR were lower when exposed to UV radiation independent of the diet. Our results show that under anthropogenic eutrophication and high solar UVR levels an increase in the nutrient input could favor only males of A. valida, by reducing the negative effects of UVR on their FCR. Nevertheless, these nutrient inputs might cause additional problems like anoxia, as a result of an unusual macroalgal growth, thus affecting amphipod's survival.

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Processing of allochthonous macrophyte subsidies by sandy beach consumers: estimates of feeding rates and impacts on food resources

Cited by 137 publications

References 43 publications

Annual cycle of wrack supply to sandy beaches: effect of the physical environment

Annual cycle of wrack supply to sandy beaches: effect of the physical environment

Niche segregation amongst sympatric species at exposed sandy shores with contrasting wrack availabilities illustrated by stable isotopic analysis

Combined impact of ultraviolet radiation and increased nutrients supply: a test of the potential anthropogenic impacts on the benthic amphipod Amphitoe valida from Patagonian waters (Argentina)

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