1. Tree pathogens are a major threat to forest ecosystems. Conservation management strategies can exploit natural mechanisms of resistance, such as tree genotype and host-associated microbial communities. However, fungal and bacterial communities are rarely looked at in the same framework, particularly in conjunction with host genotype. Here, we explore these relationships and their influence on ash dieback disease, caused by the pathogen Hymenoscyphus fraxineus, in European common ash trees.2. We collected leaves from UK ash trees and used microsatellite markers to genotype trees, quantitative PCR to quantify H. fraxineus infection load and ITS and 16S rRNA amplicon sequencing to identify fungal and bacterial communities, respectively.3. There was a significant association between H. fraxineus infection intensity and ash leaf fungal and bacterial community composition. Higher infection levels were positively correlated with fungal community alpha-diversity, and a number of fungal and bacterial genera were significantly associated with infection presence and intensity. Under higher infection loads, leaf microbial networks were characterized by stronger associations between fewer members than those associated with lower infection levels. Together these results suggest that H. fraxineus disrupts stable endophyte communities after a particular infection threshold is reached, and may enable proliferation of opportunistic microbes. We identified three microbial genera associated with an absence of infection, potentially indicating an antagonistic relationship with H. fraxineus that could be utilized in the development of anti-pathogen treatments. 4. Host genotype did not directly affect infection, but did significantly affect leaf fungal community composition. Thus, host genotype could have the potential to indirectly affect disease susceptibility through genotype × microbiome interactions, and should be considered when selectively breeding trees. 5.Synthesis. We show that the diversity, composition and network structure of ash leaf microbial communities are associated with the severity of infection from ash dieback disease, with evidence of disease-induced dysbiosis. We also show that host genotype influences leaf fungal community composition, but does not directly influence tree infection. These findings help to elucidate relationships between host genetics, the microbiome and a tree pathogen, highlighting potential resistance mechanisms and possible co-infection concerns that could inform ash tree management. K E Y W O R D S amplicon sequencing, bacteria, Fraxinus excelsior, fungi, genetic diversity, Hymenoscyphus fraxineus, microbiome, tree pathogen | 293 Journal of Ecology GRIFFITHS eT al.

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This study documented how people in an agricultural community cope with water scarcity. Through focus group discussions, household interviews, and observation, it attempts to understand how they make use of the available resources and traditional knowledge to make a livelihood. Thirty informants were involved in the study: six of which were tenants and twenty-four were landowners. Their agricultural practices were based on traditional beliefs and years of observation and experience on when to plant and how to ensure a bountiful harvest in conjunction with soil fertility and pest management. Preferred crops were those that were drought and pest resistant. Water scarcity was minimized through the use of balon, cemented deep well, water pumps, rainwater harvesting during the rainy season, and a reservoir. However, these could not supply enough for human consumption and agricultural production, especially during the dry season. Because ofthis, informants expressed the need for an irrigation system. This study illustrates the importance of traditional or local knowledge to agriculture and natural resource management by providing households with adaptive strategies. It is therefore important that this knowledge system be incorporated in the development and implementation of programs to improve the agricultural and economic productivity of farm households and the management of natural resources in the marginal uplands.

A double pot technique experiment was conducted to determine the nutrient supplying capacity of five acid soils planted with three vegetables such as cabbage (Brassica oleracea), maize (Zea mays) and tomato (Solanum lycopersicum L.). The soils used in the study were taken from Kibangay,