| 1. |
- Hansson, Lars-Anders, et al.
(författare)
-
Food-chain length alters community responses to global change in aquatic systems
- 2013
-
Ingår i: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-678X .- 1758-6798. ; 3, s. 228-233
-
Tidskriftsartikel (refereegranskat)abstract
- Synergies between large-scale environmental changes, such as climate change1 and increased humic content (brownification)2, will have a considerable impact on future aquatic ecosystems. On the basis of modelling, monitoring and experimental data, we demonstrate that community responses to global change are determined by food-chain length and that the top trophic level, and every second level below, will benefit from climate change, whereas the levels in between will suffer. Hence, phytoplankton, and thereby algal blooms, will benefit from climate change in three-, but not in two-trophic-level systems. Moreover, we show that both phytoplankton (resource) and zooplankton (consumer) advance their spring peak abundances similarly in response to a 3 °C temperature increase; that is, there is no support for a consumer/resource mismatch in a future climate scenario. However, in contrast to other taxa, cyanobacteria—known as toxin-producing nuisance phytoplankton3—benefit from a higher temperature and humic content irrespective of the food-chain composition. Our results are mirrored in natural ecosystems. By mechanistically merging present food-chain theory with large-scale environmental and climate changes, we provide a powerful framework for predicting and understanding future aquatic ecosystems and their provision of ecosystem services and water resources.
|
|
| 2. |
- Behrens, Jane W., et al.
(författare)
-
Personality- and size-related metabolic performance in invasive round goby (Neogobius melanostomus)
- 2020
-
Ingår i: Physiology and Behavior. - : Elsevier. - 0031-9384 .- 1873-507X. ; 215, s. 1-6
-
Tidskriftsartikel (refereegranskat)abstract
- Differences between individuals in behavioral type (i.e. animal personality) are ecologically and evolutionarily important because they can have significant effects on fitness components such as growth and predation risk. In the present study we are used the invasive round goby (Neogobius melanostomus) from an established population in controlled experiments to examine the relationships among personality, metabolic performance, and growth rate (inferred as size-at-age). Boldness was measured as the time to return to normal behavior after a simulated predator attack, where fish with shorter freezing times were categorized as "bold" and fish with longer times were categorized as "shy." We show that bold fish have significantly higher standard metabolic rate (SMR) than their shy conspecifics, whereas there was no difference between personality types in their maximum metabolic rate (MMR) or aerobic scope (AS). Bold fish furthermore had a smaller size-at-age as compared to shy fish. Together this provides evidence of a metabolic underpinning of personality where the high-SMR bold fish require more resources to sustain basic life functions than their low-SMR shy conspecifics, indicating that bold round goby from established populations with high densities (and high competition for food) pay a price of reduced growth rate.
|
|
| 3. |
- Ericsson, Philip, et al.
(författare)
-
Personality-dependent inter- and intraspecific foraging competition in the invasive round goby, Neogobius melanostomus
- 2021
-
Ingår i: Journal of Fish Biology. - : Wiley-Blackwell. - 0022-1112 .- 1095-8649. ; 98:5, s. 1234-1241
-
Tidskriftsartikel (refereegranskat)abstract
- This study examines the impact of boldness on foraging competition of the highly invasive round goby Neogobius melanostomus Pallas 1815. Individual risk tolerance, or boldness, was measured as the time to resume movement after a simulated predation strike. Fish that resumed movement faster were categorized as "bold," fish that took more time to resume movement were categorized as "shy" and those that fell in between these two categories were determined to have "intermediate" boldness. Competitive impacts of boldness in N. melanostomus were determined in a laboratory foraging experiment in which interspecific (juvenile Atlantic cod Gadus morhua Linnaeus 1758) and intraspecific (intermediate N. melanostomus) individuals were exposed to either bold or shy N. melanostomus competitors. G. morhua consumed fewer prey when competing with bold N. melanostomus than when competing with shy N. melanostomus, whereas intermediately bold N. melanostomus foraging was not affected by competitor boldness. Bold and shy N. melanostomus consumed similar amounts of prey, and the number of interactions between paired fish did not vary depending on the personality of N. melanostomus individuals. Therefore, intraspecific foraging competition was not found to be personality dependent. This study provides evidence that individual differences in boldness can mediate competitive interactions in N. melanostomus; nonetheless, results also show that competition is also governed by other mechanisms that require further study.
|
|
| 4. |
|
|
| 5. |
- Lindegren, Martin, et al.
(författare)
-
Towards sustainable fisheries of the Oresund cod (Gadus morhua) through sub-stock-specific assessment and management recommendations
- 2013
-
Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1095-9289 .- 1054-3139. ; 70:6, s. 1140-1150
-
Tidskriftsartikel (refereegranskat)abstract
- Fisheries management traditionally relies on stock assessments assuming discrete populations within large administrational areas. However, failing to account for sub-stock structuring may result in overestimation of the stocks' true harvest potential and unsustainable exploitation of small stock elements. Atlantic cod (Gadus morhua) frequently occurs in spatially segregated populations, some of which exhibit fine-scaled stock structuring within current management boundaries. Here we use the locally spawning cod stock in the Sound ("Oresund") as a case study, and perform a sub-stock-specific assessment to evaluate biological and economic effects of managing the Sound cod as a separate stock. Our results indicate that reducing exploitation pressure, particularly through technical regulations i. e. increasing gill-net mesh sizes, would not only enhance the stock age distribution, but yield long-term net benefits to the local gill-net fishery. Furthermore, our study emphasizes the need for developing sub-stock-specific management recommendations in order to ensure the maintenance of fisheries resources in general, and the persistence of sub-stock structuring in particular.
|
|
| 6. |
- Ljungberg, Peter, et al.
(författare)
-
Effects of small-scale habitat fragmentation on predator–prey interactions in a temperate sea grass system
- 2013
-
Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 160:3, s. 667-675
-
Tidskriftsartikel (refereegranskat)abstract
- During the last decades, fragmentation has become an important issue in ecological research. Habitat fragmentation operates on spatial scales ranging over several magnitudes from patches to landscapes. We focus on small-scale fragmentation effects relevant to animal foraging decision making that could ultimately generate distribution patterns. In a controlled experimental environment, we tested small-scale fragmentation effects in artificial sea grass on the feeding behaviour of juvenile cod (Gadus morhua). Moreover, we examined the influence of fragmentation on the distribution of one of the juvenile cod’s main prey resources, the grass shrimp (Palaemon elegans), in association with three levels of risk provided by cod (no cod, cod chemical cues and actively foraging cod). Time spent by cod within sea grass was lower in fragmented landscapes, but total shrimp consumption was not affected. Shrimp utilised vegetation to a greater extent in fragmented treatments in combination with active predation. We suggest that shrimp choose between sand and vegetation habitats to minimize risk of predation according to cod habitat-specific foraging capacities, while cod aim to maximize prey-dependent foraging rates, generating a habitat-choice game between predator and prey. Moreover, aggregating behaviour in grass shrimp was only found in treatments with active predation. Hence, we argue that both aggregation and vegetation use are anti-predator defence strategies applied by shrimp. We therefore stress the importance of considering small-scale behavioural mechanisms when evaluating consequences from habitat fragmentation on trophic processes in coastal environments.
|
|
| 7. |
- Persson, Anders, et al.
(författare)
-
Trophic interactions
- 2018
-
Ingår i: Biology and ecology of pike. - Boca Raton : CRC Press. - 9781482262902
-
Bokkapitel (refereegranskat)
|
|
| 8. |
- van Deurs, Mikael, et al.
(författare)
-
Marine ecosystem connectivity mediated by migrant-resident interactions and the concomitant cross-system flux of lipids
- 2016
-
Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 6:12, s. 4076-4087
-
Tidskriftsartikel (refereegranskat)abstract
- Accumulating research argues that migrants influence the functioning and productivity of local habitats and ecosystems along migration routes and potentially drive cross-system energy fluxes of considerable magnitude, yet empirical documentation of local ecological effects and descriptions of the underlying mechanisms are surprisingly rare. In this study, we discovered migrant-resident interactions and substantial cross-system lipid transportation in the transition zone between the Baltic Sea and the North Sea where a resident cod population (predators) was found to interact with a herring population (prey) on a seasonal basis. We traced the lipids, using fatty acid trophic markers (FATM), from the herring feeding grounds in the North Sea to the cod livers in the Western Baltic Sea. Time series analysis of population dynamics indicated that population-level production of cod is positively affected by the herring subsidies. However, the underlying mechanisms were more complicated than anticipated. During the herring season, large cod received most of its dietary lipids from the herring, whereas smaller cod were prevented from accessing the lipid pool due to a mismatch in predator-prey size ratio. Furthermore, while the herring were extremely rich in bulk energy, they were surprisingly poor in a specific functional fatty acid. Hence, our study was the first to illustrate how the magnitude cross-system fluxes of subsidies in migrant-resident systems are potentially constrained by the size structure of the resident predator population and the nutritional quality of the migrants.
|
|
| 9. |
- Waldo, Staffan, et al.
(författare)
-
Swedish coastal herring fisheries in the wake of an ITQ system
- 2013
-
Ingår i: Marine Policy. - : Elsevier. - 0308-597X .- 1872-9460. ; 38, s. 321-324
-
Tidskriftsartikel (refereegranskat)abstract
- The European common fisheries policy (CFP) advocates measures to sustain small-scale fisheries; hence, in the European Commission's proposal for a reformed CFP, these are exempted from a mandatory system with tradable fishing concessions. This opens up for management actions designed for small-scale fisheries, but also implies new management issues. This article provides insights into the topic based on a Swedish small-scale herring fishery in the western Baltic Sea that was exempted from an ITQ-system. The fishery has been profitable since the system was introduced, and the increasing effort of both incumbent fishermen and new entrants implies a situation where fishermen compete for a limited quota. The migratory pattern of the herring implies high densities in the southern parts of the fishing areas during spring and in the northern parts during autumn. This forms the basis for two different fisheries in the area, as well as for the current management proposal to divide the quota into a spring and an autumn part. This and other management proposals are discussed in the paper. The main conclusion from the case study is that, when exempting a fishery from tradable fishing concessions, it is important to build other institutions dealing with the fundamental problem of access to the quota. Failure to do so might result in an over-capacity issue and threaten the long-run development of an otherwise successful small-scale fishery.
|
|
| 10. |
- Gustafsson, Anders, et al.
(författare)
-
Priority Setting in QFD - Improvements and Implications
- 1999
-
Konferensbidrag (refereegranskat)abstract
- One of the more important purposes of QFD is to prioritize customer needs and thus know where to focus resources in the future. The standard procedure in QFD is to ask customers to state their importances and there are many disadvantages connected to this procedure. The state-of-the-art approach in customer satisfaction modeling is to derive importances from the customers' evaluation of a product. This paper compares the two approaches. The conclusion is that it is better to derive the importances since it can be expected to generate more reliable results and it is easier to interpret
|
|
