With a projected economic growth rate of 3.5% from 2011-2016, Forbes ranks the city of Atlanta as the 10th fastest-growing city in America.
While there are many benefits associated with urbanization, it can also impose negative and detrimental influences on stream communities.
Denzell Cross, a doctoral student pursuing a Ph.D. in Integrated Conservation (ICON) at UGA, investigates these long-term impacts of urbanization on the structure and function of streams in the Atlanta metropolitan area.
Advised by Dr. Krista Capps, Cross was awarded the prestigious Ford Foundation Predoctoral Fellowship which provides three years of support for study in pursuit of a doctorate degree.
To understand the impacts of urbanization, Cross monitors communities of macroinvertebrates- small spineless animals like insects, snails, and crayfish- for potentially negative signs.
“These potential negative impacts include a decreasing biotic diversity through the input of large amounts of chemicals and contaminants”
“The hydrology of these ecosystems is also often altered due to large areas of impervious surfaces like roads, sidewalks, parking lots, and rooftops, which prevent water from infiltrating into the soil,” Cross explains.
Cross hopes his research will allow greater insight into how the disturbances caused by urbanization affect these freshwater macroinvertebrate communities.
Insects, snails, and crayfish may not seem like an integral part of a stream ecosystem, but their contributions are vital.
They decompose organic matter such as leaves and twigs and filter these organic particles to make the water less turbid. They also serve as an important food source for larger aquatic creatures such as fish.
Cross’ research will couple longitudinal data with new field observations to understand how the community structure of macroinvertebrates changes in response to increasing urbanization.
He will also investigate how this change in community impacts ecosystem function.
Cross’ study will be one of a few to empirically test how disturbance-driven changes in diversity alter the functional role macroinvertebrates play in ecosystem processes.
Cross sees his research as providing a framework for the regional comparison and management of human stressors on the urban environment.
His research will also serve as a crucial early warning indicator for bioassessment and environmental monitoring programs.
After graduation, Cross plans to continue to conduct research investigating the impacts of urbanization on the structure and function of aquatic communities through a postdoctoral position, with the goal of becoming a research ecologist.
“Through my work I hope to continue studying urban freshwater systems and continue collaborating with community science groups and a diverse set of stakeholders. I hope to continue working in the southeast and would be especially excited to continue working in Atlanta.”