Augustana Digital Commons

This project will assess the impact of urban development on forest composition, diversity, and magnitude of invasive species. It will also assess landowner attitudes and behaviors towards these ecosystems and related conservation strategies.

By sampling 30 urban forest study plots along an urbanization gradient; sites ranging from close to city infrastructure (such as next to a golf course) or far away from city infrastructure (such as forest preserves), we intend to answer the following questions:

• What is the level of plant diversity between mature trees (also known as over story) and plants and shrubs (also known as understory) in these plots? Additionally, what are the levels of invasive species dominance in these urban forests?
• What is the relative importance of the land use and land-cover (i.e. types of vegetation, surfaces, infrastructure, etc.) driving observed patterns of plant community composition and diversity?
• Using a combination of interviews and surveys, we will assess landowner attitudes and behaviors towards these ecosystems and conservation strategies, which will help develop effective outreach campaigns and prioritize conservation strategies of which landowners are most amenable.

Research Objectives

Job 1: Assess composition, structure, diversity and magnitude of invasive species of riparian forests across six additional urban, suburban, and exurban (areas directly outside of a suburb) watersheds.

Objectives:

• Chose 30 forest plots (10 urban, 10 suburban and 10 exurban).
• Conduct vegetation sampling on 15 plots per year (2015-2016).
• Complete beetle and butterfly inventories on 15 plots per year (2015-2016)

Job 2: Assess landowner attitudes and behaviors towards these ecosystems and related conservation strategies.

Objectives:

• Conduct focus groups with participating landowners to develop questions for survey (spring-summer 2015).
• Design (summer 2015) and complete surveys (fall 2015).

Understory composition will be measured by setting up a 25-meter radius circular plot with six measuring tapes at each site. Vegetation sampling will occur with a researcher walking down each measuring tape and recording the plants at each meter increment.

Composition of the forest over story will be measured by splitting the plot into transects and taking inventories of the tree with smallest and largest diameter. We will collect data on soil chemistry, leaf litter cover and depth, bare soil cover, deer browse severity, tree age and other environmental variables for each site.

Using high-resolution aerial photographs, we will use the High Ecological Resolution Classification for Urban Landscapes and Environmental Systems (HERCULES) method to characterize the type (course vegetation, fine vegetation, bare soil, pavement, buildings and building type), density and arrangement of elements of the landscape within a 500-meter radius of the center of each study plot (Cadenasso et al. 2007). These structural elements of the urban landscape are predicted to strongly influence ecosystem composition, structure, and functions and will thereby be used as predictors to explain observed patterns of native biodiversity and invasive species dominance.