Isolated trees as foci of diversity in active and fallow fields Original Research Article

As the percentage of forest converted to agroecosystems in the tropics rises, it becomes increasingly important to understand how biodiversity can be managed in these ecosystems. In this study, I tested the hypotheses that insect abundance and diversity are higher near isolated trees in crop fields than in the open and that the diversity and abundance of insects increases with the density of isolated trees. Ant species richness, ant abundance and beetle abundance per trap were higher near isolated trees than in the open. Isolated trees had less of an affect on beetle abundance in fallow than active fields. Ant species richness was positively correlated with tree size. Ant species richness per field, ant abundance and beetle abundance per field were not correlated with tree density or the condition of surrounding fields. These results indicate that isolated trees can play a role in determining the local distribution of ants and beetles in crop fields.