The Middle Ridge IBA encompasses the whole elevated area that runs north-south through the center of Babeldaob Island. This IBA is bordered on almost all sides by the Compact Road or other secondary roads. The eastern boundary in Ngiwal follows the edge of the mangrove inland of Ngemai Bay and comes back to join the Compact Road. The southern boundary of the Middle Ridge IBA is contiguous with parts of the ridge that defines the Ngerikiil Watershed. The western boundary is defined as the old Japanese road, the southern boundary follows the Ikoranges River, the eastern boundary adjoined the Compact Road, and the north is contiguous with the rest of the IBA. Much of the IBA is composed of public lands.
All of Palau’s restricted-range bird species are captured in this IBA, with the exception of the Giant White-eye. Bird species also found in this IBA are the Blue-faced Parrotfinch, White-breasted Woodswallow, Common Moorhen, Pacific Black Duck, and the Grey Nightjar. Although these species do not trigger IBA criteria, they are locally significant due either to their limited numbers or distribution. Some (the Blue-faced Parrotfinch, White-breasted Woodswallow and Giant White-eye) are listed on the US Endangered Species List.
Non-bird biodiversity: This IBA includes the headwaters of all of Babeldaob’s major watersheds. The headwaters of the Ngermeskang River, the largest in Palau, is included in this IBA. The upland forests in Babeldaob are considered the most diverse in Micronesia and have a high rate of endemism (Costion and Kitalong, 2005).
Pressure/threats to key biodiversity
The Middle Ridge IBA contains much of the Rael Kedam (Path of the Frigatebird), the ridgeline of Babeldaob Island. A network of traditional stone and other walking paths can be found on or near the ridgeline. In many areas these paths have become greatly overgrown or have fallen into disrepair. It is hoped that the network of paths may be restored thus the Rael Kedam would become a key area for hiking, bird-watching and other sustainable tourism activities.
As of early 2008, the Middle Ridge IBA is sparsely populated. Much of the land is public land. Public land is often leased to individuals for farming or residential development, or to businesses for development. With the completion of the Compact Road, it is expected that most public lands throughout Babeldaob will be leased for development. Thus, habitat degradation due to accelerated development in the wake of the construction of the Compact Road, uncontrolled burning, poor or intensive agricultural practices and the introduction of alien invasive species most threaten this IBA. The conservation of this middle ridge of Babeldaob is important to protect surface water sources, minimize erosion and sedimentation that impact coral reefs, and preserve Babeldaob’s terrestrial biodiversity.
Areas of nine out of ten of the Babeldaob states are included in the Middle Ridge IBA. Management responsibility of resources within this IBA is shared by all the states whose boundaries fall within this IBA, together with private landowners.
This IBA includes the Ngardok Nature Reserve in Melekeok, which is on the Ramsar list of Wetlands of International Importance, and the proposed Ngermeskang Nature Reserve in Ngaremlengui. These two sites are now being linked together through their respective state’s membership in the Babeldaob Watershed Alliance. This initiative is an effort by a partnership of states to maximize resources, exchange lessons, and streamline efforts in managing their watersheds. Other protected areas in the Middle Ridge IBA include the Medal a Iyechad Waterfall in the state of Ngardmau and Mesekelat Conservation Area in the state of Ngchesar. This IBA captures Palau’s two freshwater lakes, Ngardok in Melekeok and Ngerkall in Ngaraard. Other significant areas that are included in this IBA, in part or whole, are proposed protected areas in Ngaraard, and various nationally registered historical sites.
BirdLife International (2020) Important Bird Areas factsheet: Middle Ridge, Babeldaob. Downloaded from
http://www.birdlife.org on 31/03/2020.