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| 2. |
- Bergström, Lena, et al.
(författare)
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Klimatförändringar och biologisk mångfald : Slutsatser från IPCC och IPBES i ett svenskt perspektiv.
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- De stora miljö- och samhällsproblemen kommer inte ensamma. De är sammankopplade på olika sätt. Detta innebär utmaningar men ger också möjligheter att utveckla åtgärder och lösningar. Det gäller både för klimatfrågan och frågan om att motverka förlusten av biologisk mångfald och ekosystem. Kunskapens betydelse för att hantera dessa och andra aspekter är ovärderlig, såväl kring specifika frågeställningar som kring omständigheter och förutsättningar för åtgärdsarbetet.Den här kunskapssammanställningen har gjorts av forskare från Lunds universitet och Sveriges lantbruksuniversitet på uppdrag av Naturvårdsverket och SMHI. Forskarna har tagit avstamp i de omfattande kunskapsutvärderingar som gjorts av den mellanstatliga klimatpanelen (IPCC) och den mellanstatliga plattformen för biologisk mångfald (IPBES). Slutsatserna från IPCC och IPBES sätts i ett svenskt perspektiv, bland annat genom utvalda exempel vilka fungerar som aktuella illustrationer av hur klimatförändringar påverkar biologisk mångfald och ekosystem i Sverige.
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| 4. |
- Borgström, Pernilla, et al.
(författare)
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Above- and belowground insect herbivores mediate the impact of nitrogen eutrophication on the soil food web in a grassland ecosystem
- 2018
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 127, s. 1272-1279
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Tidskriftsartikel (refereegranskat)abstract
- Insect herbivores are important drivers of ecosystem processes in grasslands, and can mediate the grassland's response to environmental change. For example, recent evidence shows that above- and belowground herbivory, individually and in combination, can modify how a plant community responds to nitrogen (N) eutrophication, an important driver of global change. However, knowledge about how such effects extend to the associated soil food web is lacking. In a mesocosm experiment, we investigated how communities of soil nematodes - an abundant and functionally important group of soil organisms - responded to above- and belowground insect herbivory at contrasting N levels. We found that the strongest influence of above- and belowground herbivory on the nematode community appeared at elevated N. The abundance of root-feeding nematodes increased when either above- or belowground insect herbivores were present at elevated N, but when applied together the two herbivore types cancelled out one another's effect. Additionally, at elevated N aboveground herbivory increased the abundance of fungal-feeders relative to bacterial-feeders, which indicates changes in decomposition pathways induced by N and herbivory. Belowground herbivory increased the abundance of omnivorous nematodes. The shifts in both the herbivorous and detrital parts of the soil food web demonstrate that above- and belowground herbivory does not only mediate the response of the plant community to N eutrophication, but in extension also the soil food web sustained by the plant community. We conclude that feedbacks between effects of above- and belowground herbivory mediate the response of the grassland ecosystem to N eutrophication.
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| 5. |
- Borgström, Pernilla, et al.
(författare)
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Above- and belowground insect herbivory modifies the response of a grassland plant community to nitrogen eutrophication
- 2017
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 98, s. 545-554
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the role that species interactions play in determining the rate and direction of ecosystem change due to nitrogen (N) eutrophication is important for predicting the consequences of global change. Insects might play a major role in this context. They consume substantial amounts of plant biomass and can alter competitive interactions among plants, indirectly shaping plant community composition. Nitrogen eutrophication affects plant communities globally, but there is limited experimental evidence of how insect herbivory modifies plant community response to raised N levels. Even less is known about the roles of above- and below-ground herbivory in shaping plant communities, and how the interaction between the two might modify a plant community's response to N eutrophication. We conducted a 3-yr field experiment where grassland plant communities were subjected to above- and belowground insect herbivory with and without N addition, in a full-factorial design. We found that herbivory modified plant community responses to N addition. Aboveground herbivory decreased aboveground plant community biomass by 21%, but only at elevated N. When combined, above- and belowground herbivory had a stronger negative effect on plant community biomass at ambient N (11% decrease) than at elevated N (4% decrease). In addition, herbivory shifted the functional composition of the plant community, and the magnitude of the shifts depended on the N level. The N and herbivory treatments synergistically conferred a competitive advantage to forbs, which benefited when both herbivory types were present at elevated N. Evenness among the plant species groups increased when aboveground herbivory was present, but N addition attenuated this increase. Our results demonstrate that a deeper understanding of how plant-herbivore interactions above and below ground shape the composition of a plant community is crucial for making reliable predictions about the ecological consequences of global change.
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| 6. |
- Borgström, Pernilla, et al.
(författare)
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Aboveground insect herbivory increases plant competitive asymmetry, while belowground herbivory mitigates the effect
- 2016
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Ingår i: PeerJ. - : PeerJ. - 2167-8359. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Insect herbivores can shift the composition of a plant community, but the mechanism underlying such shifts remains largely unexplored. A possibility is that insects alter the competitive symmetry between plant species. The effect of herbivory on competition likely depends on whether the plants are subjected to aboveground or belowground herbivory or both, and also depends on soil nitrogen levels. It is unclear how these biotic and abiotic factors interactively affect competition. Ina greenhouse experiment, we measured competition between two coexisting grass species that respond differently to nitrogen deposition: Dactylis glomerata L., which is competitively favoured by nitrogen addition, and Festuca rubra L., which is competitively favoured on nitrogen-poor soils. We predicted: (1) that aboveground herbivory would reduce competitive asymmetry at high soil nitrogen by reducing the competitive advantage of D. glomerata; and (2), that belowground herbivory would relax competition at low soil nitrogen, by reducing the competitive advantage of F. rubra. Aboveground herbivory caused a 46 A) decrease in the competitive ability of F. rubra, and a 23% increase in that of D. glomerata, thus increasing competitive asymmetry, independently of soil nitrogen level. Belowground herbivory did not affect competitive symmetry, but the combined influence of above and belowground herbivory was weaker than predicted from their individual effects. Belowground herbivory thus mitigated the increased competitive asymmetry caused by aboveground herbivory. D. glomerata remained competitively dominant after the cessation of aboveground herbivory, showing that the influence of herbivory continued beyond the feeding period. We showed that insect herbivory can strongly influence plant competitive interactions. In our experimental plant community, aboveground insect herbivory increased the risk of competitive exclusion of F. rubra. Belowground herbivory appeared to mitigate the influence of aboveground herbivory, and this mechanism may play a role for plant species coexistence.
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| 7. |
- Borgström, Pernilla, et al.
(författare)
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Below‑ground herbivory mitigates biomass loss from above‑ground herbivory of nitrogen fertilized plants
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Herbivorous insects can infuence grassland ecosystem functions in several ways, notably by alteringprimary production and nutrient turnover. Interactions between above- and belowground herbivorycould afect these functions; an efect that might be modifed by nitrogen (N) addition, an importantglobal change driver. To explore this, we added above- (grasshoppers) and belowground (wireworms)insect herbivores and N into enclosed, equally composed, grassland plant communities in a fullyfactorial feld experiment. N addition substantially altered the impact of above- and belowgroundherbivory on ecosystem functioning. Herbivory and N interacted such that biomass was reduced underabove ground herbivory and high N input, while plant biomass remained stable under simultaneousabove- and belowground herbivory. Aboveground herbivory lowered nutrient turnover rate in thesoil, while belowground herbivory mitigated the efect of aboveground herbivory. Soil decompositionpotential and N mineralization rate were faster under belowground herbivory at ambient N, butat elevated N this efect was only observed when aboveground herbivores were also present. Wefound that N addition does not only infuence productivity directly (repeatedly shown by others), butalso appears to infuence productivity by herbivory mediated efects on nutrient dynamics, whichhighlights the importance of a better understanding of complex biotic interactions.
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| 8. |
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| 9. |
- Borgström, Pernilla
(författare)
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Impacts of insect herbivory and nitrogen eutrophication on grassland ecosystems
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nitrogen (N) eutrophication causes severe species richness declines in grassland ecosystems worldwide. Species interactions, for example between plants and herbivores, are likely to mediate the grassland’s response to increased N availability. However, attempts to investigate how herbivores might modify ecosystem-level N impacts have so far focused near-exclusively on the aboveground subsystem. Such approaches overlook the importance of the great number of belowground interactions that occur among plants, herbivores and other organisms. A great challenge in global change ecology is to understand how the above- and belowground subsystems interact to determine the ultimate, ecosystem-level impact of N eutrophication and other global change drivers. In this thesis, I present controlled experiments that were carried out to explore the role of above- and belowground insect herbivory in mediating interactions among plant species, and how the interaction between above- and belowground herbivory determines the response of the grassland to N eutrophication. In a field experiment, I found that above- and belowground herbivory determined the impact of N eutrophication on the grassland ecosystem, in terms of plant community composition, ecosystem functioning, and the soil food web. N and herbivory synergistically conferred a competitive advantage to forbs over grasses, as the former strongly benefited from the presence of both herbivory types at elevated N. Nutrient turnover displayed inverted responses to above- and belowground herbivory at contrasting N levels. Additionally, the shifts in the plant community extended to shifts in the functional composition of the soil nematode community. In a parallel plant competition experiment, I found that belowground herbivory mitigated an increased competitive asymmetry caused by aboveground herbivory. I conclude that insect herbivores can be important mediators of the impact of N eutrophication on grasslands, and that their mediating role will depend on whether both above- and belowground herbivores are present. Therefore, the ecosystem-level impact of herbivory above ground should, whenever possible, be studied alongside that of herbivory below ground, as the omission of either herbivory type could lead to erroneous conclusions about the role of the other.
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| 10. |
- Borgström, Pernilla, et al.
(författare)
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Växtskydd i raps, åkerbönor och ärter: kunskapsbehov och forskningsinriktningar
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport är framtagen på initiativ av en fokusgrupp för växtskydd i avbrottsgrödor som bildats inom Plattform växtskydd vid SLU. Rapportens syfte är att identifiera betydande kunskapsluckor som behöver fyllas om ett effektivt och hållbart växtskydd ska kunna uppnås i raps, åkerbönor och ärter, som är de arealmässigt viktigaste avbrottsgrödorna till spannmål i Sverige. I sammanställningen beskrivs ett tjugotal av de främsta skadegörarna som angriper dessa grödor samt vilka befintliga växtskyddsåtgärder som finns att tillgå vid angrepp. De mest angelägna kunskapsbehoven och lovande forskningsinriktningarna presenteras också för respektive skadegörare; dessa har fastställts genom litteraturstudier och diskussioner med experter. I rapporten identifieras och diskuteras slutligen också gemensamma teman av kunskapsluckor för flera olika skadegörare. Vi konstaterar att det för flera virus och markburna patogener finns stora kunskapsluckor vad gäller den grundläggande biologin och skadegörarnas förekomst och utbredning i Sverige. Det finns också bristande kunskap om flera skadegörares spridningsmönster, till exempel flygavstånd för insekter. Resistensförädling identifieras som en övergripande och lovande väg framåt för att utveckla växtskyddet mot speciellt patogener som inte kan bekämpas kemiskt, som kransmögel, klumprotsjuka och Turnip Yellows Virus i raps, samt rotrötor i ärter och åkerbönor. Vidare illustrerar vår sammanställning att odlingssystemet, speciellt växtföljden, är central för att hantera många patogener, ogräs och insekter. Särskilt för en del markburna patogener är långa odlingsuppehåll det enskilt viktigaste sättet att begränsa angrepp. Förändringar i hur grödorna odlas, såsom samodling eller etablering med reducerad markbearbetning, påverkar hela samhällen av skadegörare, men oftast studeras bara effekterna på en skadegörare åt gången, utan att hänsyn tas till eventuella samspelseffekter mellan olika skadegörare. Rapporten belyser också att det finns kunskapsluckor som behöver fyllas för att vi genom ett integrerat växtskydd ska få bästa möjliga effekt av direkt bekämpning mot skadegörare, till exempel utveckling av tillförlitliga prognosmetoder och/eller välgrundade bekämpningströsklar. Vi drar slutsatsen att en förväntat omfattande framtida odling av raps, åkerbönor, ärter och närbesläktade kål- och ärtväxter i Sverige, i ett förändrat klimat och med en begränsad tillgång till kemiska bekämpningsmedel, kommer att ställa växtskyddet inför stora utmaningar. För att möta dessa utmaningar kommer det krävas forskning som kan ta fram motståndskraftiga grödor, odlingssystem som missgynnar skadegörare samt kompletta strategier för integrerat växtskydd som kan hantera uppkomna skadegörarproblem genom behovsanpassad bekämpning med låg miljöbelastning.
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