RESEARCH PROJECT

Cloud water (fog) capture is critically important for the maintenance of cloud forest ecosystems: trees intercept water droplets from the air, condensing them and leading to their deposition on the soil surface at higher rates than if plants were not there. Trees also add organic material to soils, halt erosion, help with water infiltration, and buffer soil surfaces from drying sun and wind. Thus, plants have a positive effect on ecosystem water capture, and in turn, ecosystem water retention has a positive effect on plant growth.

Such positive feedbacks help create ecosystems that are resilient to change. Unfortunately, once part of the equation is lost, the system moves into an equally resilient degraded state: if there are no plants to capture water, then there is also no moisture for seed germination, and the system becomes ‘stuck’ in a degraded state. If further dried out by a changing climate, such degraded, resilient states can become even harder to restore.

Various techniques have been developed to deal with harsh climate and soil conditions in restoration projects in other locations. In areas that receive fog inundation but lack the ability to intercept water droplets due to a lack of trees, synthetic fog capturing devices have been used to “harvest” water and deposit it onto the soil surface available for plant uptake. Various prototypes of such structures have been implemented globally.

Our study focuses on potentially rebuilding this relationship by using fog capture systems to help to water seedlings. Kanakaleonui Bird Corridor (KBC) has a degraded Sophora chrysophylla (māmane) forest currently dominated by exotic grasses, highly eroded soils, and few native trees (Leopold and Hess, 2017). While this current grassland could potentially serve as a corridor for endangered birds between Hakalau Forest NWR and Mauna Kea Forest Reserve at higher elevations, it is currently a fire risk, given the abundant fuel loads created by the dry, exotic grasses. We are working with Department of Hawaiian Homelands (DHHL), Mauna Kea Watershed Alliance (MKWA), and U.S. Fish and Wildlife (FWS), who currently help manage this corridor. We hope to better understand the benefits that capturing fog water can bring to this high elevation, low precipitation, and high invasive-grass matrix, in the hopes of ultimately regenerating a native forest.