PARENT SESSION
Contributed Oral Session 90: Urban Ecology: Management
Wednesday, August 10, 8:00 AM - 11:30 AM, Meeting Room 524 C, Level 5, Palais des congrès de Montréal
Effects of local and regional habitat variables on urban insect diversity.
Cox, Kevin*,1, Langellotto, Gail1, 1 Fordham University, Bronx, NY
ABSTRACT- On a global basis, urban areas are increasing in number, density, and land area. Although it is generally believed that urban ecosystems do not provide ecosystem services, urban biodiversity may yield benefits such as water, gas and disturbance regulation, nutrient cycling, refugia, food production, urban cooling, energy conservation, environmental education and recreation, and pollination. In New York City, more than 600 community gardens have been created on abandoned lots since the 1970's. These urban gardens represent highly fragmented and managed habitats that may be utilized by a variety of insect species. Urban gardens vary in area, local (within-garden) habitat variables, and in the make-up of the surrounding urban matrix (regional landscape). In 2003-4, insect biodiversity was assessed in 19 community gardens in the Bronx and East Harlem, New York. Visual point counts of butterflies complemented by water pan traps were used to sample insect diversity. Garden habitat variables were quantified and percentage green of the regional landscape was determined using GIS. A total of 17 butterfly species were observed in gardens, with the cabbage white butterfly (Pieris rapae) making up the majority of observations. For insects other than butterflies, 7,301 individuals of approximately 130 unique morphotypes were collected from pan traps. There was a significant relationship between garden size and the number of butterfly species and insect morphotypes observed within a garden. Local and regional habitat availability and quality differed among gardens. Multivariate regression and ANOVA was used to test relationships between overall diversity and diversity of select insect guilds (hymenopteran and lepidopteran pollinators, and hymenopteran parasitoids) with local habitat complexity and regional habitat availability. Diversity of insect guilds exhibited variable responses to habitat characteristics at the local and regional spatial scales.
Key words: urban, insect, biodiversity, gardens