3 research outputs found

    Search for top-down and bottom-up drivers of latitudinal trends in insect herbivory in oak trees in Europe

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    AimThe strength of species interactions is traditionally expected to increase toward the Equator. However, recent studies have reported opposite or inconsistent latitudinal trends in the bottom‐up (plant quality) and top‐down (natural enemies) forces driving herbivory. In addition, these forces have rarely been studied together thus limiting previous attempts to understand the effect of large‐scale climatic gradients on herbivory.LocationEurope.Time period2018–2019.Major taxa studiedQuercus robur.MethodsWe simultaneously tested for latitudinal variation in plant–herbivore–natural enemy interactions. We further investigated the underlying climatic factors associated with variation in herbivory, leaf chemistry and attack rates in Quercus robur across its complete latitudinal range in Europe. We quantified insect leaf damage and the incidence of specialist herbivores as well as leaf chemistry and bird attack rates on dummy caterpillars on 261 oak trees.ResultsClimatic factors rather than latitude per se were the best predictors of the large‐scale (geographical) variation in the incidence of gall‐inducers and leaf‐miners as well as in leaf nutritional content. However, leaf damage, plant chemical defences (leaf phenolics) and bird attack rates were not influenced by climatic factors or latitude. The incidence of leaf‐miners increased with increasing concentrations of hydrolysable tannins, whereas the incidence of gall‐inducers increased with increasing leaf soluble sugar concentration and decreased with increasing leaf C : N ratios and lignins. However, leaf traits and bird attack rates did not vary with leaf damage.Main conclusionsThese findings help to refine our understanding of the bottom‐up and top‐down mechanisms driving geographical variation in plant–herbivore interactions, and indicate the need for further examination of the drivers of herbivory on trees.</p

    Climate, host and geography shape insect and fungal communities of trees

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    13 Pág.Non-native pests, climate change, and their interactions are likely to alter relationships between trees and tree-associated organisms with consequences for forest health. To understand and predict such changes, factors structuring tree-associated communities need to be determined. Here, we analysed the data consisting of records of insects and fungi collected from dormant twigs from 155 tree species at 51 botanical gardens or arboreta in 32 countries. Generalized dissimilarity models revealed similar relative importance of studied climatic, host-related and geographic factors on differences in tree-associated communities. Mean annual temperature, phylogenetic distance between hosts and geographic distance between locations were the major drivers of dissimilarities. The increasing importance of high temperatures on differences in studied communities indicate that climate change could affect tree-associated organisms directly and indirectly through host range shifts. Insect and fungal communities were more similar between closely related vs. distant hosts suggesting that host range shifts may facilitate the emergence of new pests. Moreover, dissimilarities among tree-associated communities increased with geographic distance indicating that human-mediated transport may serve as a pathway of the introductions of new pests. The results of this study highlight the need to limit the establishment of tree pests and increase the resilience of forest ecosystems to changes in climate.We gratefully acknowledge the financial support of the Swiss National Science Foundation (Project C15.0081) Grant 174644 and the Swiss Federal Office for the Environment Grant 00.0418.PZ/P193-1077. This work was supported by COST Action “Global Warning” (FP1401). CABI is an international intergovernmental organisation, and R.E., M.K., H.L. and I.F. gratefully acknowledge the core financial support from our member countries (and lead agencies) including the United Kingdom (Foreign, Commonwealth and Development Office), China (Chinese Ministry of Agriculture and Rural Affairs), Australia (Australian Centre for International Agricultural Research), Canada (Agriculture and Agri-Food Canada), Netherlands (Directorate General for International Cooperation), and Switzerland (Swiss Agency for Development and Cooperation). See https://www.cabi.org/aboutcabi/who-we-work-with/key-donors/ for full details. M.B. and M.K.H. were financially supported by the Slovak Research and Development Agency (Project APVV-19-0116). H.B. would like to thank the botanist Jorge Capelo who helped with Myrtaceae identification and INIAV IP for supporting her contribution to this study. Contributions of M. de G. and B.P. were financed through Slovenian Research Agency (P4-0107) and by the Slovenian Ministry of Agriculture, Forestry and Food (Public Forestry Service). G.C, C.B.E. and A.F.M. were supported by OTKA 128008 research grant provided by the National Research, Development and Innovation Office. Contributions of K.A. and R.D. were supported by the Estonian Research Council grants PSG136 and PRG1615. M.J.J., C.L.M. and H.P.R. were financially supported by the 15. Juni Fonden (Grant 2017-N-123). P.B., B.G. and M.Ka. were financially supported by the Ministry of Science and Higher Education of the Republic of Poland for the University of Agriculture in Krakow (SUB/040013-D019). C.N. was financially supported by the Slovak Research and Development Agency (Grant APVV-15-0531). N.K. was partially supported by the Russian Science Foundation (grant № 22-16-00075) [species identification] and the basic project of Sukachev Institute of Forest SB RAS (№ FWES-2021-0011) [data analysis]. R.OH. was supported by funding from DAERA, and assistance from David Craig, AFBI. T.P. thanks the South African Department of Forestry, Fisheries and the Environment (DFFE) for funding noting that this publication does not necessarily represent the views or opinions of DFFE or its employees. In preparing the publication, materials of the bioresource scientific collection of the CSBG SB RAS “Collections of living plants indoors and outdoors” USU_440534 (Novosibirsk, Russia) were used. M.Z. was financially supported by Ministry of Science, Technological Development and Innovation of the Republic of Serbia (contract no. 451-03-47/2023-01/200197). We acknowledge the Genetic Diversity Centre (GDC) at ETH Zurich for providing computational infrastructure and acknowledge the contribution of McGill University and Génome Québec Innovation Center (Montréal, Quebec, Canada) for pair-end sequencing on Illumina MiSeq. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe
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