Seeds often suffer high levels of mortality while in the seed bank. Fungal pathogens are thought to be an important source of this mortality, but little is known about their occurrence or effects in natural communities. In this study, I explored interspecific variation in the effects of fungal pathogens on seed survival in a range of natural systems, as well as the effects of soil moisture on fungal activity. A survey of seed pathogens revealed that fungal colonists varied among host plant species and included both generalists and specialists. The impacts of these pathogens depended on the plant and fungal species involved: different levels of pathogenicity occurred depending on the particular plant-fungus combination. Finally, there was weak evidence that habitat differences, such as soil moisture, affect fungal activity. Overall, my results provide further evidence that fungal attack of seeds in the seed bank may significantly influence plant communities.