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Animals, such as termites, have largely been overlooked as global-scale drivers of biogeochemical cycles1,2, despite site-specific findings3,4. Deadwood turnover, an important component of the carbon cycle, is driven by multiple decay agents. Studies have focused on temperate systems5,6, where microbes dominate decay7. Microbial decay is sensitive to temperature, typically doubling per 10°C increase (decay effective Q10 = ~2)8–10. Termites are important decayers in tropical systems3,11–13 and differ from microbes in their population dynamics, dispersal, and substrate discovery14–16, meaning their climate sensitivities also differ. Using a network of 133 sites spanning 6 continents, we report the first global field-based quantification of temperature and precipitation sensitivities for termites and microbes, providing novel understandings of their response to changing climates. Temperature sensitivity of microbial decay was within previous estimates. Termite discovery and consumption were both much more sensitive to temperature (decay effective Q10 = 6.53), leading to striking differences in deadwood turnover in areas with and without termites. Termite impacts were greatest in tropical seasonal forests and savannas and subtropical deserts. With tropicalization17 (i.e., warming shifts to a tropical climate), the termite contribution to global wood decay will increase as more of the earth’s surface becomes accessible to termites. Acknowledgements. For materials, field, and lab assistance, we thank the Australian Landscape Trust Team, Juan Martínez de Aragón, Eric Roy, Hugh Wilson, Kylie Brice, Bethanie Coleman, Brendan Delroy, Coline Deveautour, Suzanne Donn, Generci Assis Neves, Ricardo Marques Barreiros, Ricardo Marques Barreiros, Generci Assis Neves from Resineves Agroflorestal company, Alfred Lochner, Pousada Vale do Céu, Humberto Robles, María M. Rivera, and Grant Kirker. Steve Allison and Tom Crowther provided comments on the manuscript and Abbey Yatsko helped with figure and manuscript formatting. Funding for this work was provided by US National Science Foundation (DEB-1655759, 2149151, 1713502, 1713435, 1647502, 1546686, 1831952), George Washington University, USDA Forest Service, Centre College Faculty Development Funds, Australia Terrestrial Ecosystem Research Network (TERN) National Collaborative Research Infrastructure Strategy (NCRIS), Royal Society-FCDO Africa Capacity Building Initiative, New Phytologist Foundation, Fondecyt grant:1160329, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brasil (CAPES), Department of Ecology and Conservation of the Federal University of Lavras, CNPq, FAPEMIG, Australian Academy of Science 2017 Thomas Davies Research Grant, Australian Research Council (DP160103765), UK National Environment Research Council (NE/L000016/1), Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil (NERC - FAPESP)19/07773-1, Environment Research and Technology Development Fund (ERTDF; JPMEERF15S11420) of the Environmental Restoration and Conservation Agency (ERCA) of Japan, COLCIENCIAS (No. FP44842-046-2017), Spanish Government (grant PID2019-110521GB-I00), Catalan Government (grant SGR 2017-1005), Fundación Ramón Areces (grant ELEMENTAL-CLIMATE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT) PICT 2019- 2472, National Agency for the Promotion of Research, Technological Development and Innovation, Scientific and Technological Research Project 2018-01561 (PICT 2018- 01561), iDiv German Research Foundation (DFG– FZT 118, 202548816), European Research Council (ERC), European Union's Horizon 2020 research and innovation program (grant agreement no. 677232).

INTRODUCTION Pollinators are animals that play an essential role in the reproduction of many plants by transferring genetic material, in the form of pollen, from male to female flower parts. Becaus...

Arboreal fungal endophytes are a highly diverse group of organisms associated with asymptomatic tissues and some of them are latent pathogens. The knowledge of fungal endophytes is limited, because previous studies mainly focused on foliar fungal endophytes of a limited number of host species and locations. We assessed the fungal endophyte diversity in twigs of congeneric native and exotic tree species belonging to eleven angiosperm and gymnosperm genera in mostly temperate regions of 32 countries on six continents. We describe how host taxonomy and geographic location affect endophyte diversity and how diversity differs between native and exotic trees. More than 400 samples were collected on both hemispheres and fungal communities were assessed by high-throughput sequencing. Sampling was done in winter, because trees are mostly traded in winter, when deciduous trees lack foliage. We found around 15, 000 fungal Exact Sequence Variants (ESVs) associated with the tree genera. ESV richness varied among sampled taxa, but did not differ between native and exotic hosts. ESV richness in most of the northern hemisphere tree genera peaked at 45-50 degrees of latitude, but the pattern for southern hemisphere genera was not clear. The endophyte communities of angiosperms and gymnosperms differed ; around 30% of all ESVs were found in a single genus and less than 1% was found in all genera. Distinct geographic patterns among and within continents were found and the similarity of the endophyte communities decreased with distance between sampling locations in most genera. This study reveals fungal endophyte diversity on an unprecedented scale as a result of the wide geographic and taxonomic diversity of the samples. The geographic differences in ESVs in particular suggest that international live plant trade can facilitate the exchange of geographically isolated fungal communities, which could threaten tree-based resources in importing countries.

Live plants are often traded in their dormant stage, among other reasons to reduce the introduction of new pests. However, the pests associated with this pathway are largely unknown. Risk mitigation relies on pest risk assessments which can only be performed for known pests. It is therefore important to identify potential pests before the introduction occurs. In addition, post arrival host shifts are very difficult to predict. Several studies attempted to estimate the likelihood of host shifts based on existing literature data on known pest-host associations, but the number of pests in these studies was often limited and the data were unlikely collected in the same place and at the same time. To overcome these problems, we performed a global study which aimed at detecting potential insect pests and fungal pathogens on selected congeneric native and exotic tree species in 33 countries. Samples were taken in botanical gardens and arboreta on the Northern and Southern hemisphere. At each location, twenty 50 cm long twigs were collected from tree species of up to six genera and kept in containers with water at room temperature for insect emergence. Emerged insects were collected and identified based on morphology and DNA barcoding of the mitochondrial DNA COI region. DNA was also extracted from pooled buds, twig parts and needles for the identification of fungi based on the ribosomal DNA ITS region using a high-throughput sequencing approach. Here, we present the first results of this study and discuss them in the context of pest risk assessment.