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Location Palau, Aimeliik,Airai,Melekeok,Ngaraard,Ngardmau,Ngaremlengui,Ngatpang,Ngchesar,Ngiwal
Central coordinates 134o 34.00' East  7o 30.00' North
IBA criteria A1, A2
Area 13,767 ha
Altitude 0 - 245m
Year of IBA assessment 2008

Palau Conservation Society

Site description 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.

Key Biodiversity 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).

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Micronesian Scrubfowl Megapodius laperouse resident  2005  present  A1, A2  Endangered 
Palau Ground-dove Alopecoenas canifrons resident  2005  present  A2  Near Threatened 
Palau Fruit-dove Ptilinopus pelewensis resident  2005  present  A2  Least Concern 
Micronesian Imperial-pigeon Ducula oceanica resident  2005  present  A2  Near Threatened 
Palau Owl Pyrroglaux podargina resident  2005  present  A2  Least Concern 
Palau Swiftlet Aerodramus pelewensis resident  2005  present  A2  Least Concern 
Todiramphus cinnamominus resident  2005  present  A2  Not Recognised 
Micronesian Myzomela Myzomela rubratra resident  2005  present  A2  Least Concern 
Morningbird Pachycephala tenebrosa resident  2005  present  A2  Least Concern 
Palau Fantail Rhipidura lepida resident  2005  present  A2  Least Concern 
Mangrove Flycatcher Myiagra erythrops resident  2005  present  A2  Least Concern 
Palau Bush-warbler Cettia annae resident  2005  present  A2  Least Concern 
Caroline Islands White-eye Zosterops semperi resident  2005  present  A2  Least Concern 
Dusky White-eye Zosterops finschii resident  2005  present  A2  Least Concern 
Micronesian Starling Aplonis opaca resident  2005  present  A2  Least Concern 

IBA Monitoring

2008 medium not assessed low
Poor - based on little, or potentially unreliable/unrepresentative, data

Residential and commercial development tourism and recreation areas likely in long term (beyond 4 years) some of area/population (10-49%) slow but significant deterioration medium

Some of site covered (10-49%)  No management plan exists but the management planning process has begun  Some limited conservation initiatives are in place  low 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Lake Ngardok Nature Reserve 493 protected area contained by site 493  
Lake Ngardok Wetlands of International Importance (Ramsar) 493 protected area contained by site 493  


IUCN habitat Habitat detail Extent (% of site)
Forest Lower montane rain forest (tropical); Lowland forest - mixed swamp  major
Savanna   minor
Wetlands (inland) Freshwater lakes and pools; Rivers & streams  minor

Land use

Land-use Extent (% of site)
agriculture minor
Notes: includes wetland taro, small family plots, larger commercial farms (multiple crops)
nature conservation and research minor
not utilised major
water management minor

Protection status 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.

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Middle Ridge, Babeldaob. Downloaded from on 27/11/2014

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