| 1. |
- Kortsch, Susanne, et al.
(författare)
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Landscape composition and pollinator traits interact to influence pollination success in an individual-based model
- 2023
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Ingår i: Functional Ecology. - 0269-8463. ; 37:7, s. 2056-2071
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Tidskriftsartikel (refereegranskat)abstract
- The arrangement of plant species within a landscape influences pollination via changes in pollinator movement trajectories and plant–pollinator encounter rates. Yet the combined effects of landscape composition and pollinator traits (especially specialisation) on pollination success remain hard to quantify empirically. We used an individual-based model to explore how landscape and pollinator specialisation (degree) interact to influence pollination. We modelled variation in the landscape by generating gradients of plant species intermixing—from no mixing to complete intermixing. Furthermore, we varied the level of pollinator specialisation by simulating plant–pollinator (six to eight species) networks of different connectance. We then compared the impacts of these drivers on three proxies for pollination: visitation rate, number of consecutive visits to the focal plant species and expected number of plants pollinated. We found that the spatial arrangements of plants and pollinator degree interact to determine pollination success, and that the influence of these drivers on pollination depends on how pollination is estimated. For most pollinators, visitation rate increases in more plant mixed landscapes. Compared to the two more functional measures of pollination, visitation rate overestimates pollination service. This is particularly severe in landscapes with high plant intermixing and for generalist pollinators. Interestingly, visitation rate is less influenced by pollinator traits (pollinator degree and body size) than are the two functional metrics, likely because ‘visitation rate’ ignores the order in which pollinators visit plants. However, the visitation sequence order is crucial for the expected number of plants pollinated, since only prior visits to conspecific individuals can contribute to pollination. We show here that this order strongly depends on the spatial arrangements of plants, on pollinator traits and on the interaction between them. Taken together, our findings suggest that visitation rate, the most commonly used proxy for pollination in network studies, should be complemented with more functional metrics which reflect the frequency with which individual pollinators revisit the same plant species. Our findings also suggest that measures of landscape structure such as plant intermixing and density—in combination with pollinators' level of specialism—can improve estimates of the probability of pollination. Read the free Plain Language Summary for this article on the Journal blog.
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| 2. |
- Novotny, Andreas, 1991-, et al.
(författare)
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DNA metabarcoding highlights cyanobacteria as the main source of primary production in a pelagic food web model
- 2023
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Ingår i: Science Advances. - 2375-2548. ; 9:17
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Tidskriftsartikel (refereegranskat)abstract
- Models that estimate rates of energy flow in complex food webs often fail to account for species-specific prey selectivity of diverse consumer guilds. While DNA metabarcoding is increasingly used for dietary studies, methodological biases have limited its application for food web modeling. Here, we used data from dietary metabarcoding studies of zooplankton to calculate prey selectivity indices and assess energy fluxes in a pelagic resource-consumer network. We show that food web dynamics are influenced by prey selectivity and temporal match-mismatch in growth cycles and that cyanobacteria are the main source of primary production in the investigated coastal pelagic food web. The latter challenges the common assumption that cyanobacteria are not supporting food web productivity, a result that is increasingly relevant as global warming promotes cyanobacteria dominance. While this study provides a method for how DNA metabarcoding can be used to quantify energy fluxes in a marine food web, the approach presented here can easily be extended to other ecosystems.
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| 3. |
- Novotny, Andreas, et al.
(författare)
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Integrating DNA metabarcoding and biomonitoring data reveals trophic pathways of primary production in a flux-balance marine food web
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Estimating energy fluxes, or weight of trophic interactions, in food webs allows linking food web structure to properties of ecosystem functioning. Due to limitations in traditional methods, resolved food-web models are often binary or based on body size. Species-specific feeding traits and weights of interactions are typically not included, particularly at the base of the pelagic food web. Consequently, models are prone to underestimate the trophic diversity of species interactions.Here, we focus on trophic pathways of primary production in the Baltic Sea using a bioenergetic model that includes several trophic levels from primary producers to fish. For the first time, dietary DNA metabarcoding data of zooplankton are combined with accumulated biomass data from long-term pelagic monitoring and metabolic theory in a network model to describe energy pathways, including the diversity of planktonic organisms.We show that picocyanobacteria and filamentous cyanobacteria are the main contributors to secondary production in the Baltic Sea and that the latter experience high predation pressure from zooplankton. In contrast, the combination of high biomasses and low predation pressure on dinoflagellates and diatoms suggests that a significant fraction of the spring bloom is not utilized in the pelagic food web, explaining the high export of biological material to the sea seafloor.This study can be used to address ecosystem management objectives in the Baltic Sea under changing environmental conditions. Furthermore, the novel framework presented in this study, integrating DNA metabarcoding and biomonitoring data to assess energy fluxes, can be extended to dynamic food web modeling in other ecosystems.
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