Research

Kristy King Announces Insect Study Results

Factors Contributing to the Assembly and Maintenance of Insect Communities in Manhattan Community Gardens
By Kristy King, MS Conservation Biology, Columbia University

ABSTRACT

My research aims to determine what factors are contributing to the assembly and maintenance of insect communities in Manhattan community gardens. The effects of plant structural complexity, food crop diversity, neighboring land uses, and trees bordering the garden were measured and used as independent variables to predict the diversity, abundance, and ratio of parasitoid wasps and Hemipteran pests. Over fifty morphospecies of parasitoid wasps and seven families of Hemipteran pests were collected over a two-month period in twenty community gardens. Plant structural complexity was found to have no discernable effect on pests or parasitoids in community gardens, but the abundance of pests is positively associated with the diversity of food crops in the gardens (p<0.005; Adj. R2= 0.3384). Parasitoid wasp richness is explained by a combination of pest abundance and the number of trees within a 1m radius of land around each garden (p<0.005; Adj. R2= 0.4067). This implies that insects may be experiencing the landscape on a much larger scale than originally believed, and that individual garden management may not be an important driver of beneficial insect communities in these urban habitat fragments.

Specifics for West 104th Street gardens:
- 21 parasitoid wasps collected; 10 wasp morphospecies collected (this is pretty average, compared with the other gardens that I studied)
- But! Six unique wasp species were collected in the West 104th street gardens! This is high, compared with the other gardens that I worked in. So, of the nearly sixty morphospecies collected in all twenty gardens, roughly one-tenth of them were unique to the West 104th Street gardens. This may be something you can brag about in the grant proposal (a unique and beneficial insect community).
- Plant structural complexity in the West 104th Street garden is average, compared with other New York community gardens.

About the Author:
Kristy King is a graduate student in Conservation Biology at Columbia University. This research was developed for her Master’s thesis. Ms King has general interests in urban ecology, and after graduation in May 2008, she will begin a position with the NYC Parks Department.