Research Projects

Landscape Position and Hillslope Hydrology Associated with the Middle Ranch Hayfield Restoration

PI: Eric McDonald
Co-PIs: Todd Caldwell, Tom Bullard

Funded by: Catalina Island Conservancy and CALEM

Right: Panoramic view shot to the west, Middle Ranch Hayfield

Keywords: infiltration, soil moisture, water balance, revegetation, Catalina, aspect, scrub oak

Project Description

This is a collaborative effort with the Conservancy and serves as a pilot project to demonstrate the importance of assessing the soil water balance for the purposes of revegetation efforts and monitoring of this island ecosystem. Hydrologic characterization of both hillslope and valley bottom alluvial deposits is needed to develop both conceptual and numerical models for oak restoration work currently being conducted on Catalina Island, CA. Monitored soil microclimate indicates significant differences in available moisture between north- and south-facing slopes, and the valley bottom.

Soil moisture monitoring systems and a weather station were installed and operational as of 18 March 2004. The system consists of (1) a primary monitoring station that has an extensive combination soil moisture, soil temperature, and weather station sensors, and (2) 5 satellite soil moisture stations on both north and south facing hillslopes. The primary station was established to record key changes in soil moisture and temperature in the area of the Hayfield where oak restoration is currently being conducted. It also serves as a fully upgradeable base station for future additions of monitoring equipment or additional satellite stations. Each hillslope station is paired with a combination of sensors installed under an oak canopy and a second set in the adjacent interspace area. This design provides soil moisture and temperature data on soil beneath island scrub oak canopies and in the interspace areas.

Below: This panoramic shot to the west depicts the importance of landscape position and vegetation across the Middle Ranch Hayfield. North slopes (left side) have a lush cover of grasses and oaks. Conversely, south-facing slopes (right side) have cacti and open interspaces.

Below: Oak restoration along the valley bottom resulted from the overgrazing of the island by the introduction of feral goats in the 1800's. Restoration is further complicated by Catalina's controlled, non-native bison herd introduced in the 1920's.