Faculty Sponsor: Dr. Peroni
Urbanization decreases the abundance of native species, which may enable exotics to experience enemy release in urban areas, enhancing their invasive capacity. The invasive autogamous orchid, Spathoglottis plicata, acquires some biotic resistance in Puerto Rico from a native orchid weevil specialist, Stethobaris polita. The distribution of S. polita along an urbanization gradient may affect the distribution of S. plicata and its future spread. To determine the effect of land cover on both species and the impact of S. polita on the spread of S. plicata, we modeled the distribution of the interaction between the two species and additionally assessed weevil abundance and the damage they do in different land cover types and localities. Land cover was the most important predictor of distribution for both species. Spathoglottis plicata occurs in forests, pastures, and urban areas; however, S. polita is largely absent from urban areas, including urban forests, and along rivers within wet forests. This distribution likely reflects the dispersal ability of S. plicata, in addition to potential human intervention, and the inability of S. polita to penetrate or become established within the urban matrix. Thus, within the invasive range of S. plicata in Puerto Rico, geographical heterogeneity in acquired interactions is expected to result in higher seed production within areas of enemy release. The orchid is likely to spread more rapidly in urban forests, as well as along forest rivers, where S. polita is sparse.