• Start-up
  • Planning
  • Action
  • Evaluation

This project seeks to assist the recovery of a former cattle ranch to a self-sustaining, biologically diverse, multi-layered native forest. A multi-layered community structure would increase moisture retention and provide an abundance of ecosystem services, such as wildlife habitat, endangered species recovery, and opportunity for education and cultural practices. 

From the mid-19th century to 2010, the Kahuku pasture was grazed by cattle, transforming native forest to a savanna of scattered ‘ōhi‘a and koa trees and non-native pasture grass. As rising temperatures and increased drought influence the spread and mortality of non-native and native vegetation, respectively, manager intervention is needed to recover and sustain the diverse native plant communities that formerly existed.

Project Area

Kahuku Paddocks System
The project focuses on 1,200 of the 12,138 acres of former cattle pasture within the Kahuku Unit, acquired as part of Hawai‘i Volcanoes National Park in 2003. Kahuku sits on the southern slopes of Mauna Loa and holds a dynamic history of volcanic and human activity. In the last 150 years, Kahuku was grazed by cattle and cleared of forest understory. Most of the original native forest has been replaced by a savanna of scattered ‘ōhi‘a and koa trees and non-native pasture grass. Bands of native forest exist on the dry western edge of the pastures, while montane rain forest spans the wet eastern margin of the pastures. A broad range of diverse environments exist between these two extremes. Since 2004, the park has committed substantial resources to constructing boundary fences and excluding non-native ungulates. These introduced animals are the primary threat to native plant communities and wildlife. With these efforts, as well as those to remove select invasive vegetation, some native vegetation has recovered. However, increasing temperatures, drought frequency, and drought magnitude complicate recovery.

Management Goals

Open Pasture, Credit: Mark Wasser, NPS

The goal of this project is to assist the recovery of a self-sustaining, biologically diverse, multi-layered native forest in Kahuku. Repairing fencing and removing remaining ungulates will minimize unintended disruption to vegetation. Restoration, replenishing, and monitoring of native plant species, in addition to invasive plant species control, will allow greater establishment of intended species. Preventing extinction of rare plant species requires increasing population sizes of rare, threatened, and endangered native plant species, as well as fortifying a genetic safety net. Creating a seed bank or nursery for extant species will foster this goal. Fuel loads from a history of grazing, matched with increasing temperature and drier conditions, necessitates fire preparation. Evaluating fuel breaks, re-positioning water sources, developing site closure protocols, and creating educational materials will better position Kahuku to prevent fires from occurring. Lastly, the appropriate funding for these goals needs to be acquired, either through grant applications or leveraging resources from existing programs in the area. 

Climate Change Impacts

For this project, the most important anticipated climate change impacts include:
Increased temperature - Rising temperatures can contribute to expansion of invasive plants, disease, and pest outbreaks;
Increased drought (frequency and magnitude) - Prolonged periods of dry conditions can contribute to lower survival rates for natural and planted seedlings. Likewise, drought could lead to adult vegetation mortality;
Increase fire risk - Fine fuels, resulting from a legacy of cattle grazing, will continue to dominate Kahuku for many decades. Due to increased temperatures and drier conditions, flammability and opportunity for fire has grown;
Increased storms – storms such as hurricanes have direct impact on vegetation and property damage, including fence washouts and tree falls which can crush fences, allowing ungulates to enter protected areas.

Challenges and Opportunities

Climate change will present challenges and opportunities for accomplishing the management objectives of this project, including:

Challenges

Storms and fire can damage fences, allowing ungulates to enter delicate spaces. These stochastic events can extirpate species with small population sizes or negatively impact newly planted areas.
At this moment, it is unknown how warmer and drier conditions will stress plants’ reproductive cycles and establishment in restoration efforts.
Warmer and drier conditions could expand suitable habitat for existing and new invasive species, including vegetation and insects.
Visitors may be opposed to temporary closures and reduced access in the event of fire or restoration efforts.

Opportunities

Dire climate conditions would facilitate restoration efforts. For example, dry days create better conditions for chemically treating invasive plants.
Temporary closures provide an educational opportunity on climate change, drought, and fire impact for visitors to the park. Closures could motivate visitors to explore under-appreciated parts of the park.
The Biden Administration has placed climate change as a top priority, which has led to a variety of initiatives meant to center climate change and fund necessary actions.

Adaptation Actions

Project participants used the Adaptation Workbook to develop several adaptation actions for this project, including:

Area/Topic
Approach
Tactics
Maximize Native Forest Regeneration
Exclude all ungulates via fencing and removal.
Build Drought Resilient Communities
Identify drought-tolerant native species. Determine if seeds (e.g., ‘ōhi‘a, māmane) collected from drier areas produce plants with greater drought tolerance.
Protect Forest Recovery
Monitor at rates to detect and remove disruptive vegetation.
Build Capacity for Rare Species to Recover
Collect and store seeds of rare, threatened, and endangered plant species.
Create meta-populations across the modeled ecological range.
Build Fire Tolerant Communities
Collect, store, and propagate fire tolerant species following fire occurrence.

Monitoring

Project participants identified several monitoring items that could help inform future management, including:
Ungulate presence
Planted seedling survival
Invasive plant cover and detection of incipient species
Viable seed collections, including rare and fire tolerant species
Fire risk to inform temporary closure

Learn More

To learn more about this project, contact
Courtney
.

Keywords

Coastal
Fire and fuels
Forest threats
Forest types
Invasive species
Restoration