In island ecosystems, seabirds strongly affect soil properties and plant communities by transporting nutrients from the sea and by physical disturbances through their nesting. I introduce results of two studies that evaluate the effects of seabird nesting on plant growth via local-scale alterations in soil chemical properties on a subtropical island in Japan. The first topic is quantification of the relationships among aboveground vegetation biomass, soil chemical properties, seabird nesting, and other environmental factors. We found that increases in soil nutrients were affected indirectly, via seabird nesting, by topography and vegetation type. The second topic is quantification of plant growth on soils collected from sites with various distances from a seabird nest. Distance from a nest was negatively correlated with quantity of soil nutrients and positively correlated with pH. The relationship between dry weight of plants and soil chemical properties were not significant. These results indicate that seabird nesting altered soil chemical properties at the local scale, while the alterations did not necessarily promote plant growth.