L13_Urban Riparian (1)

Riparian Zones and Their Importance

• Riparian Zones: Areas adjacent to rivers and streams that support diverse ecosystems.

  • Function as buffers between terrestrial and aquatic environments.

  • Play a crucial role in ecological functioning, including water quality maintenance and habitat provision.

Urbanization Effects on Riparian Zones

• Urbanization impacts riparian zones differently across various landscapes.

  • Increased runoff often leads to channel incision.

  • Alterations in nitrogen (N) cycle dynamics due to urban development.

Nitrogen Retention in Riparian Zones (Page 2)

• Functions of Riparian Zones: Nitrogen retention crucial for ecosystem health.

  • Natural nitrogen flux includes inputs and various uptake mechanisms.

  • Components: Corn uptake, vegetative uptake, and litter fall.

  • Management strategies should focus on maintaining these natural processes.

Nitrogen Cycle and Stream Health (Page 4)

• Basic nitrogen cycle involves:

  • Nitrogen Fixation: Conversion of atmospheric N2 into compounds usable by plants.

  • Nitrification: Transformation of ammonia (NH4+) into nitrates (NO3-).

  • Denitrification: Conversion of nitrates back to atmospheric nitrogen.

Case Studies of Urban Systems (Page 5-6)

• Baltimore, MD (Temperate Climate) vs. Sacramento, CA (Semi-arid Climate):

  • How climate variations influence nitrogen cycles.

  • Summer irrigation in Sacramento increases water availability affecting stream flows.

Changes in Riparian Tree Canopy (Page 11)

• Urbanization led to noticeable changes in canopy size and density from 1937 to 2014.

  • Mean canopy width: Displayed nearly a doubling effect over the years.

  • Denser canopies observed near smaller streams suggesting a complex relationship with urban density.

Water Stress in Riparian Trees (Page 20)

• Research Question:

  • Investigates the relationship between channel incision, summer flow, and water stress in woody plants.

  • Hypothesis: Increased summer flow could alleviate water stress for trees, but higher incision levels may negate benefits.

Denitrification Processes (Page 23)

• Focus on soil moisture and organic matter to understand denitrification:

  • Effects of bank height on soil conditions that influence N cycling.

  • Findings suggest that moisture and organic content are more favorable for denitrification at lower levels of incision.

Water Quality Concerns Beyond Nitrogen (Page 26-30)

• Concerns regarding runoff from urban pesticide use (pyrethroids).

  • Data highlights the increase in pesticide use and its potential impact on aquatic life.

  • Study findings indicate regulation of such pollutants is critical to ecosystem health.

Key Review Questions (Page 31)

• Understand the differences in water cycle pools and fluxes between urban and non-urban landscapes.

  • Impacts on water runoff characteristics due to urbanization: timing, quantity, quality, location.

  • Differentiate between point source and non-point source pollution.

  • Draw and explain nitrogen cycles, focusing on urban influences and consequences.

  • Explore the riparian zone's role in mitigating nitrogen export in urban settings.