Print PageFungi are important plant pathogens at key life history stages of recruitment, and can influence plant community structure through negative feedbacks. Much is known of the identities and specificity of pathogens in agriculture and forest management systems. An increasing body of literature shows fungal pathogens to be important sources of mortality in tropical forest seedlings, with potentially diversity-enhancing roles in tropical forest communities. Our research was conducted at the Las Cuevas Research Station in the Chiquibul Maya Mountain Forest Reserve of Belize. We used fungicide experiments, culturing of microfungi from diseased leaf tissue, and experimental infection of healthy seedlings with fungal spores to test the specificity of strains of putatively pathogenic fungi within the seedling community.
Results/Conclusions
We found that fungal pathogens are an important source of seedling mortality, rapidly driving seedling densities from 80-300 seedlings to less than 1 seedling /m2 for one common tree species. Infection trials with putative pathogens isolated from multiple species of seedlings in this forest revealed that pathogens show broad host range but species-specific virulence and that seedling hosts vary in susceptibility. The genetic characterization of fungal taxa infecting a range of tropical seedling hosts highlights the low specificity of plant-associated fungi in species rich communities. The broad host range of these fungal pathogens could mediate the outcomes of interspecific competition among tropical forest seedlings in direct and indirect ways. Further characterization of these complex interactions will shed light on the diversity-enhancing roles of pathogens in tropical forests and contribute to our growing understanding of fungal biogeography and biodiversity.
