Relationships among remotely sensed canopy data and herbivorous insect abundances in urban forests

Background/Question/Methods

Forest canopy insects are known to strongly influence multiple facets of forest ecosystem functioning. The abundance and distribution of herbivorous insects are controlled by a complex of factors, including climate and plant quality. As ectotherms, temperature influences insect growth and development. Plant quality also strongly regulates insect growth and development, but at the landscape level is spatially variable. Remote-sensing techniques provide the opportunity to measure canopy temperature, foliar quality, and tree species composition at large spatial scales. Using a combination of imaging spectroscopy and field data, we determined the influence of remotely sensed information on insect abundance in urban forests.

Results/Conclusions

We found that canopy measurements were strongly correlated with chewing insect abundance across multiple forest types in an urban landscape. In contrast, none of the commonly-used vegetation indices generated had significant relationships with chewing insect abundance. In addition, other feeding-guilds examined did not demonstrate the same relationships with remotely sensed information as did chewing insects. These findings suggest that remote sensing  may be utilized to characterize spatial variability in insect distribution and abundance at landscape scales.