Implications of plant origin, vegetative structure, and yard management on arthropod herbivory patterns in residential landscapes

Background/Question/Methods

Urban landscapes are islands and corridors for wildlife between fragmented ecosystems. Depending on the management of these areas, they can be significant contributors to local biodiversity, supporting many trophic levels and providing ecosystem services. Herbivory is one sign of these interactions between flora and wildlife. In this study, we determine how aspects of residential landscape design and management affect arthropod herbivory. To answer this question, we surveyed herbivory pressure and plant community diversity and structure in 240 plots within 30 residential yards across 4 socioeconomically diverse neighborhoods in Gainesville, Florida, USA. In addition, we surveyed homeowners about their yard management practices, including chemical applications and water usage. Herbivory severity and type (chewing, internal feeding, and sap feeding) was noted for all plant species within each surveyed plot. We hypothesize that herbivory occurrence and type are positively related to plant diversity and structural complexity. We also hypothesize declines in herbivory with increased chemical inputs and increased herbivory with more irrigation, due to improved plant palatability. Finally, we hypothesize herbivory to be less detrimental to plant health in yards having more native plants.

Results/Conclusions

Field observations suggest groundcover herbivory has a positive relationship with canopy cover and a negative relationship with lawn management intensity. Formal analyses evaluate the strength of these relationships. Collectively, findings from these analyses increase our understanding of how variation in residential landscape design and maintenance affect herbivory. Practical implications of this study include principles for designing landscapes to support higher trophic levels and mitigate negative economic and environmental impacts of arthropod pests. Future analyses will relate ecosystem services, including perceived aesthetic value, to the level of herbivore stress in residential yards.