| 1. |
- Tano, Stina A., et al.
(författare)
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Tropical seaweed beds as important habitats for juvenile fish
- 2017
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Ingår i: Marine and Freshwater Research. - 1323-1650 .- 1448-6059. ; 68:10, s. 1921-1934
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Tidskriftsartikel (refereegranskat)abstract
- Seaweed beds within tropical seascapes have received little attention as potential fish habitat, despite other vegetated habitats, such as seagrass meadows and mangroves, commonly being recognised as important nurseries for numerous fish species. In addition, studies of vegetated habitats rarely investigate fish assemblages across different macrophyte communities. Therefore, the aim of the present study was to investigate the role of tropical seaweed beds as fish habitat, particularly for juvenile fish, by comparing their fish assemblages with those of closely situated seagrass beds. Fish assemblages were assessed by visual census in belt transects, where fish were identified and their length estimated, and habitat variables were estimated for each transect. The abundance of juvenile fish in seaweed beds was twice as high as that in seagrass meadows, whereas there was no difference in total, subadult or adult fish abundance. In addition, the abundance of commercially important and coral reef-associated juveniles was higher in seaweed beds, as was fish species richness. Fish assemblages differed between habitats, with siganids being more common in seagrass meadows and juvenile Labridae and Serranidae more common in seaweed beds. These results highlight that tropical seaweed beds are important juvenile fish habitats and underscore the need to widen the view of the shallow tropical seascape.
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| 2. |
- Tano, Stina A., et al.
(författare)
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Extensive spread of farmed seaweeds causes a shift from native to non-native haplotypes in natural seaweed beds
- 2015
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Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 162:10, s. 1983-1992
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Tidskriftsartikel (refereegranskat)abstract
- Seaweed farming has been the cause of introductions of non-indigenous seaweed species and genotypes throughout the world. In Zanzibar, Tanzania, foreign genotypes of Eucheuma denticulatum were introduced for farming purposes in 1989, and in recent years a spread of non-indigenous haplotypes has been reported. The current study aimed to investigate the presence and extent of introduced and native haplotypes of E. denticulatum as well as their relative frequencies, to obtain the severity of the spread of cultivated seaweed and the current state of the native populations. The results show that all investigated sites are dominated by the introduced South-east Asian haplotypes, even where seaweed farming has never occurred. As the frequencies of East African haplotypes are remarkably low, this shows a shift from native to introduced E. denticulatum. This shift may, at least in part, be caused by earlier overharvest of natural seaweed populations, and indicates a cryptic invasion of the introduced haplotypes at the potential cost of the recovery of the native haplotype populations.
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| 3. |
- Tano, Stina, et al.
(författare)
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Tropical seaweed beds are important habitats for mobile invertebrate epifauna
- 2016
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Ingår i: Estuarine, Coastal and Shelf Science. - : Elsevier BV. - 0272-7714 .- 1096-0015. ; 183, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Marine macrophyte habitats in temperate regions provide productive habitats for numerous organisms, with their abundant and diverse invertebrate epifaunal assemblages constituting important linkages between benthic primary production and higher trophic levels. While it is commonly also recognized that certain vegetated habitats in the tropics, such as seagrass meadows, can harbour diverse epifaunal assemblages and may constitute important feeding grounds to fish, little is known about the epifaunal assemblages associated with tropical seaweed beds. We investigated the abundance, biomass and taxon richness of the mobile epifaunal community (>= 1 mm) of tropical East African seaweed beds, as well as the abundance of invertivorous fishes, and compared it with that of closely situated seagrass meadows, to establish the ecological role of seaweed beds as habitat for epifauna as well as potential feeding grounds for fish. The results showed that seaweed beds had a higher abundance of mobile epifauna (mean SD: 10,600 +/- 6000 vs 3700 +/- 2800 per m(2)) than seagrass meadows, as well as a higher invertebrate biomass (35.9 +/- 46.8 vs 1.9 +/- 2.1 g per m(2)) and taxon richness (32.7 +/- 11.8 vs 19.1 +/- 6.3 taxa per sample), despite having a lower macrophyte biomass. Additionally, the high abundance of invertivorous fishes found in seaweed beds indicates that they act as important feeding grounds to several fish species in the region.
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| 4. |
- Enge, S., et al.
(författare)
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A REVIEW OF HERBIVORE EFFECTS ON SEAWEED INVASIONS
- 2017
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Ingår i: OCEANOGRAPHY AND MARINE BIOLOGY: AN ANNUAL REVIEW, VOL 55. - BOCA RATON : Taylor and Francis. - 9781138197862 - 9781351987592 ; , s. 421-440
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Almost 300 non-native seaweeds are identified worldwide and an increasing number of these are classified as invasive with potential negative effects on the diversity and functioning of native ecosystems. Marine herbivores affect seaweed biomass and community structure in marine habitats across the globe. Consequently, herbivore-seaweed interactions are expected to be important for the establishment and invasion success of non-native seaweeds. To synthesize current knowledge of consumer effects on non-native seaweeds, we performed a meta-analysis on feeding preferences of native herbivores for non-native versus native seaweeds. Data were included from 35 studies, published from 1992-2015 and comprising 18 non-native seaweeds. Results showed that overall, native herbivores tended to prefer to feed on native rather than non-native seaweeds. Preferences were, however, variable across studies with significant differences between taxonomic and functional groups of seaweeds. In particular, filamentous red non-native seaweeds were of low palatability to native herbivores. No general feeding preferences were apparent between natives and non-natives for brown and green seaweeds, or for leathery and corticated seaweeds. In addition, we reviewed the existing studies on the effects of consumers on the performance of native and non-native seaweeds in invaded communities. This indicated that non-native seaweeds performed better than their native competitors in the presence of grazers, but in many cases had superior competitive abilities also in the absence of herbivory. To achieve a comprehensive evaluation of consumers' role in seaweed invasion success, future research should have a larger focus on manipulative community experiments, ideally on time scales that include seasonal changes and complete life cycles of the seaweeds.
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| 5. |
- NYSTRÖM SANDMAN, ANTONIA, et al.
(författare)
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VALUES – värdering av akvatiskta livsmiljöers ekosystemtjänster
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Ekosystemtjänster kan bidra till att synliggöra värden i naturen som människor är beroende av för sin överlevnad och sin välfärd. Värdet av ekosystemtjänster behöver också tydligt och systematiskt integreras i politiska beslut och i förvaltningen av våra gemensamma naturresurser, på alla dess nivåer.Övergödningen av Östersjön är ett fortsatt stort problem. Projektet Values har visat hur kartering, kvantifiering och värdering av ekosystemfunktioner kan användas för att visa på värde och nytta av olika typer av ekosystemtjänster i relation till mänsklig påverkan i form av invasiva arter och övergödning i två studiesystem, djupa sedimentbottnar och grunda kustområden.I rapporten visas att vi för att kunna ta hänsyn till ekosystemtjänster i beslutsfattande och förvaltning, behöver kartlägga dem och övervaka förändringar i deras tillstånd. Studien visar på ett konkret sätt hur begreppet ekosystemtjänster kan komma till praktisk nytta.Den här rapporten är ett resultat från ett av sju projekt inom forskningssatsningen Värdet av ekosystemtjänster och har författats av forskare vid AquaBiota Water Research, SLU och SU Östersjöcentrum. Projektet finansierades av Naturvårdsverkets miljöforskningsanslag.
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| 6. |
- Sagerman, Josefin, et al.
(författare)
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Low feeding preference of native herbivores for the successful non-native seaweed Heterosiphonia japonica
- 2015
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Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 162:12, s. 2471-2479
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Tidskriftsartikel (refereegranskat)abstract
- Non-native seaweeds constitute a conspicuous component of many benthic coastal communities. Seaweed invaders are known to significantly affect invaded communities, but relatively little is known about the mechanisms underlying their success. In this study, we explored the feeding preferences of three generalist herbivores for the successful non-native red alga Heterosiphonia japonica and native seaweed competitors. The experiments were conducted on the Swedish Skagerrak coast (58°52′N, 11°08′E) from July to August. Additionally, chemical and physical traits of the seaweeds were assessed to mechanistically explain herbivore preferences. The results showed that H. japonica was of low preference to native herbivores and that this was most likely explained by chemical properties of the invader. We were, however, not able to determine whether the low preference was caused by deterrent metabolites or low nutritional quality. We conclude that herbivore avoidance may be important for the survival and success of H. japonica in the introduced range and that efficient means of escaping herbivory may be a common feature of invaders in seaweed communities. © 2015, Springer-Verlag Berlin Heidelberg.
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| 7. |
- Wikström, Sofia A., et al.
(författare)
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Cover of coastal vegetation as an indicator of eutrophication along environmental gradients
- 2016
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Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 163:12
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Tidskriftsartikel (refereegranskat)abstract
- Coastal vegetation communities are important for primary production, biodiversity, coastal protection, carbon and nutrient cycling which, in combination with their sensitivity to eutrophication, render them potential indicators of environmental status for environmental policies like the EU Water and Marine Strategy Framework Directives. We evaluated one potential indicator for coastal vegetation, the cumulative cover at depths where the vegetation is light limited, by investigating its response to eutrophication along gradients in natural conditions. We used a large data set covering the Swedish coastline, spanning broad gradients in nutrient level, water clarity, sea-bed substrate, physical exposure and climate in addition to a salinity gradient from 0.5 to 30.5. Macroalgal cover increased significantly along gradients of declining nutrient concentration and increasing water clarity when we had accounted for diver effects, spatio-temporal sampling variability, salinity gradients, wave exposure and latitude. The developed empirical model explained 79% of the variation in algal cover across 130 areas. Based on this, we identified macroalgal cover as a promising indicator across the Baltic Sea, Kattegat and Skagerrak. A parallel analysis of soft-substrate macrophytes similarly identified significant increases in cover with decreasing concentrations of total nitrogen and increasing salinity, but the resulting empirical model explained only 52% of the variation in cover, probably due to the spatially more variable nature of soft-substrate vegetation. The identified general responses of vegetation cover to gradients of eutrophication across wide ranges in environmental settings may be useful for monitoring and management of marine vegetation in areas with strong environmental gradients.
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