Environmental Impact Assessment
Project Number: 52111-001 February 2020
Samoa: Alaoa Multi-purpose Dam Project
Volume 2: Terrestrial Biodiversity and Habitat Assessment (Part 3 of 9)
Prepared by Hydro-Electric Corporation for the Asian Development Bank.
This environmental impact assessment is a document of the borrower. The views expressed herein do not necessarily represent those of ADB's Board of Directors, Management, or staff, and may be preliminary in nature. Your attention is directed to the “terms of use” section on ADB’s website.
In preparing any country program or strategy, financing any project, or by making any designation of or reference to a particular territory or geographic area in this document, the Asian Development Bank does not intend to make any judgments as to the legal or other status of any territory or area.
Alaoa Multipurpose Dam - Revision No: 1 E307132 22 August 2019
ALAOA MULTIPURPOSE
DAM
Terrestrial biodiversi ty and habitat assessment
E307132 22 August 2019
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Alaoa Multipurpose Dam - Revision No: 1 E307132 22 August 2019
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1. Document information Title Alaoa Multipurpose Dam
Terrestrial biodiversity and habitat assessment
Client organisation Asian Development Bank
Client contact Jean Williams
Document number E307132
Project manager
Project reference P513660
Revision history Revision 1
Revision description Final Issue
Prepared by Toeolesulusulu Cedric Cedric Schuster (via 08/08/2019 Schuster email)
Reviewed by Andrew Taylor/Will Elvey Andrew Taylor (via email) 21/08/2019
Approved by Richard Herweynen 22/08/2019
(name) (signature) (date) Distributed to Jean Williams Asian Development Bank 22/08/2019
(name) (organisation) (date)
Alaoa Multipurpose Dam - Terrestrial biodiversity and habitat assessment Revision No: 1 E307132 22 August 2019 2. Executive summary Terrestrial environmental surveys were conducted as part of the overall EIA to determine the habitat types and habitat condition within and around the proposed area for the multipurpose Alaoa Dam. The terrestrial surveys assessments included terrestrial flora and birds. Surveys were conducted from July 2018 to November 2018. The project area of influence, estimated to be around 300 hectares, is located within the 8336ha wider Apia Catchment Area. The Apia Catchment is one of the Key Biodiversity Areas (KBA) in Samoa as identified in the National Biodiversity Strategy and Action Plan. Within this KBA are the densely populated areas of Vailima on the west and Maagiagi on the eastern end of the project site., the riparian watershed areas and upland montane forests. The biodiversity assessment found that most of the project area of influence (PAI) had undergone significant conversion from its original natural habitat of lowland and ridge rainforest to one that is made up of some plantation area, some fallow lands, and mixed forest of invasive trees species, secondary forest trees and some remnants of lowland rainforest trees. The bird surveys noted dominance of invasive bird species, native birds that normally present in open areas and around human settlements and birds that normally occupy the edge forests. Based on the status of the flora and the fauna found during the survey, it is concluded that the site is classified as a modified habitat. The original habitat of lowland rainforest and ridge rainforest has now been completely altered to a mix of disturbed forest dominated by invasive tree species interspersed with invasive vines and weeds The changes in the biodiversity of the site is due to human interventions in the form of land clearing for plantations and hunting. Natural occurrences in the form of cyclones and flooding have further altered the natural state of the environment where much of the area of the project site is open or covered predominantly by vines, invasive tree species and secondary forest trees. The surveys did not find in the project site or in the surrounding area any of the two birds and one plant trigger species - Samoan Bush Palm (Niu vao), Tooth-Billed Pigeon (Manumea), Ground Dove (Tuaimeo), and Mao (Maomao)- which can classify the area as a critical habitat as per the definition in Asian Development Bank Safeguard Policy Statement 2009,. The flora surveys support the absence of the bird’s species of conservation concern with the area mostly covered by invasive trees species which do not support the traditional foraging and food sources for native bird species. Previous studies of the wider Apia Catchment KBA are consistent with the conclusions of this assessment that the trigger species are not present in the project site but are found in the uppercatchment areas of the KBA where the forest is in better condition and with limited to no human influence. The trigger bird species absence can be attributed to birds moving to higher elevations and more mature forests as well as away from human settlements and plantations and predatory alien invasive species such as cats and rats. It is therefore concluded that the project area of influence is will not impact the survival of any of the conservation trigger species. Some potential short and long term impacts to the native biodiversity are identified with mitigation measures to ensure the construction and operation of the multipurpose dam will not adversely
impact the present and future survival of biodiversity. The project can also provide some activities such as replanting that will support a rehabilitation in and around the project site. In summary, while the implementation of the project will cause loss of terrestrial habitat, the current habitat has been highly modified by human intervention, is dominated by invasive species and holds no species of conservation concern. Moreover, the implementation of the project provides an opportunity for habitat enhancement, through a replanting program to rehabilitate native ecosystems along the edge of the project area of influence and scheduled monitoring during the construction period will improve knowledge of the biodiversity within the area.
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3. Contents
Executive summary i
Glossary and Acronyms 6
1. Introduction 7 1.1 Category A Project 7 1.2 Project Area of Influence: 7 1.3 Survey Methodology 8
2. Literature Review 10 2.1 Samoa’s Biodiversity 10 2.1.1 Terrestrial Biodiversity 10 2.1.2 Birds of Samoa 11 2.2 Vaisigano Watershed: Natural Habitat 15 2.3 Apia Catchment Key Biodiversity Area 15
3. Survey Results 17 3.1 Project Area of Influence: 17 3.1.1 Construction Footprint and Inundated Zone 17 3.1.2 Maagiagi and Alaoa West: 22 3.1.3 Terrestrial Mammals 25 3.2 Outside the Project Area of Influence 26 3.2.1 Fale ole Fee and Upper Vaisigano Catchment 26 3.2.2 Birds 29
4. Natural and Critical Habitat Assessment: 31 4.1 Habitat Definitions: 31 4.1.1 Modified Habitat 31 4.1.2 Natural habitat assessment 31 4.1.3 Critical habitat assessment 31 4.2 Project Area of Influence: Modified Habitat 31 4.3 Critical habitat assessment 33 4.4 Flora and Fauna Species of Conservation Concern: 34 4.4.1 Birds 34
5. Potential Impacts 36 5.1 Short Term Impacts 36 5.1.1 Flora: 36 5.1.2 Birds: 36 5.1.3 Mammals: 37 5.2 Possible Long-Term Impacts 37
6. Potential Mitigations: Recommendations 37
7. References 39
ii Alaoa Multipurpose Dam - Terrestrial biodiversity and habitat assessment Revision No: 1 E307132 22 August 2019 List of figures
Figure 1: Survey locations 9
Figure 2: Apia Catchment Key Biodiversity Area 16
Figure 3:Project Area of Influence 17
Figure 4: Ecosystems types at the project site 33
List of tables
Table 1: Status of Samoa's Land Birds of Concern 12
Table 2:Status of Samoa Sea Birds of Concern 14
Table 3: Apia Catchment Key Biodiversity Area 16
Table 4: Ecosystem Types within the Survey sites 18
Table 5: Plant list for Project Influence Area 20
Table 6: Plant list for Maagiagi and Alaoa sites 23
Table 7: Bird Survey List in Project Area of Influence 24
Table 8: Ecosystem types outside the project area of influence 26
Table 9: Fale o le Fee and Upper-catchment Plant List 28
Table 10: Bird Surveys: Outside Project Area of Influence 30
Table 11: Ecological Values of habitats within the Apia Catchment KBA 32
Table 12: Critical Habitat Assessment 34
Plates
Plates 1: Fallow lands at the proposed inundated area 19
Plates 2: fallow and plantation lands mixed with invasive tree dominated forest 19
Plates 3: Alaoa: fallow lands and invasive species: 22
iv
Plates 4: Alien invasive species dominated ridges 23
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Plates 6: Fale o le Fee: undisturbed native forest 27
Plates 7: Upper Alaoa Catchment: Disturbed Native Forest 27
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4. Glossary and Acronyms Biodiversity: The variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.
Critical Habitat: A subset of both natural and modified habitat that deserves attention. Critical habitat includes areas with high biodiversity value, including habitat required for the survival of critically endangered or endangered species; areas having special significance for endemic or restricted-range species; sites that are critical for the survival of migratory species; areas supporting globally significant concentrations or numbers of individuals of congregatory species; areas with unique assemblages of species or that are associated with key evolutionary processes or provide key ecosystem services; and areas having biodiversity of significant social, economic, or cultural importance to local communities.
Modified Habitats: Areas that may contain a large proportion of plant and/or animal species of nonnative origin, and/or where human activity has substantially modified an area’s primary ecological functions and species composition. In practice, natural and modified habitats exist on a continuum that ranges from largely untouched, pristine natural habitats to intensively managed modified habitats.
Natural Habitat: Land and water areas where the biological communities are formed largely by native plant and animal species, and where human activity has not essentially modified the area’s primary ecological functions.
Significant Conversion or Degradation: (i) the elimination or severe diminution of the integrity of a habitat caused by a major, long-term change in land or water use; or (ii) the modification of a habitat that substantially reduces the habitat’s ability to maintain viable populations of its native species.
5. 1. Introduction This report provides a summary of the baseline terrestrial habitat types (as per the Asian Development Bank (ADB) Safeguard Policy Statement 2009 (SPS) definitions), habitat conditions and biodiversity values for the project area of influence (PAI) and construction footprint for the Alaoa Multi-purpose Dam within the Vaisigano River catchment. The report will highlight any areas of natural or critical habitat and the proposed implementation strategies for the project to avoid and/or mitigate potential impacts on those habitats and the biodiversity that occurs in them. The Terrestrial Assessment is presented in six sections, plus references, with this first section providing an introduction to the project. Subsequent sections are:
• Section 2 – Literature Review;
• Section 3 – Survey Results
• Section 4 – Natural and Critical Habitat Assessment;
• Section 5 – Potential Impacts; and
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• Section 6 – Mitigation and Recommendations.
5.1 1.1 Category A Project The biodiversity assessment undertaken was the result of the Initial Environmental Screening recommendation whereby the project was classified as a Category A according to ADB Safeguards Policy Statement 2009. Category A. projects are likely to have significant adverse environmental impacts that are irreversible, diverse, or unprecedented. These impacts may affect an area larger than the sites or facilities subject to physical works. Therefore, the key aim of the surveys and assessment were to identify the biodiversity and ecosystems that could be permanently adversely affected by the project, provide recommendations on mitigation measures, or identify that the project will cause unacceptable levels of impact that cannot be mitigated adequately and should not proceed. 1.2 Project Area of Influence: The proposed multipurpose dam PAI consists of the dam, an inundated zone, construction site and penstock. The 59.6-metre-high dam wall located on the combined eastern branch of the Vaisigano River 6.5 kilometres upstream from where the river discharges into Apia Bay. At full supply level (FSL) the dam will inundate 0.2 km2 (20 hectares) of riverbed, valley floor, and hillslope habitats in the middle region of the Vaisigano Catchment, including a 1.3-kilometre length of the middle-eastern branch and a 1.1-kilometre reach of the eastern branch of the Vaisigano River. The area of inundation is less than two percent of the Vaisigano catchment.
A penstock will run 360 metres downstream from an outlet on the dam along the right bank of the river to the new power station. The existing Alaoa Power Station discharges into the Vaisigano River 80 metres upstream from the proposed new power station but is located on the opposite bank.
It is assumed that a construction camp1 will be located close to the dam. Material for construction of the dam will be obtained from within the inundated area, removing the need for offsite borrow areas. The Contractor may base his administration buildings outside the PAI, but the footprint will be small, and impacts can be managed through normal site practices, identified in the Environmental Management Plan (EMP) that forms part of the Environmental Impact Assessment (EIA) for the project and a Site-Specific Environmental Management Plan (SEMP) prepared by the Contractor and approved by the Client before work commences on site. The Contractor environmental performance will be audited against the SEMP by the Construction Supervision Consultant (CSC). It has been assumed that construction material storage and processing areas will be located inside the inundation area. Transport of imported construction materials, between the Port and the construction site, will be on the existing road network.
1.3 Survey Methodology The survey methodology utilised was based on the SPREP’s Guidelines for Undertaking Rapid Biodiversity Assessments in Terrestrial and Marine Environments in the Pacific 2014 and utilised Environmental Safeguards as set out in the ADB Safeguards Policy Statement (2009). Furthermore, the same methodology was also used in the Samoa National Ecological Survey for lowland Forests (1991) and Samoa Ecological Survey for Upland Forests (1997) as well as the Samoa Important Bird Areas (2010) which identified Key Biodiversity Areas for Samoa. The biodiversity surveys included terrestrial flora and avifauna. These were conducted in October and November 2018 over a period of 15 days. The surveys were conducted in three
1 Including office administration facilities, material storage areas and processing areas (crushing and grading material and concrete manufacturing)
6 Alaoa Multipurpose Dam - Terrestrial biodiversity and habitat assessment Revision No: 1 E307132 22 August 2019 main locations with up to six survey points at each location. Figure 1 shows where the survey points are located 1. The project area of influence (project site and East Alaoa and upper catchment) : a. the site for the proposed dam, b. Inundated zone and construction footprint c. Surrounding areas of the construction footprint that could be impacted by the project 2. Outside the project area of influence (Location 3 Fale o le Fee): a. Upper-catchment which will not be affected by the project
The general survey included was as follows: 1. GPS location recorded 2. Photo record 3. Bird Survey o 5-minute point surveys at 200m intervals along the path o For endangered and threatened birds, a running tally was taken when heard or seen along the survey path o Bird surveys were conducted in the early morning or late afternoon when birds were most active. The proposed inundated dam site had 10 bird survey points which were surveyed twice to ensure a comprehensive assessment was done. The remaining three survey locations (west boundary, east boundary and upper- catchment) had five bird survey points each as indicated in Figure 1. Additional time was also spent on interviews with local people with historic / traditional knowledge regarding the sites
4. Terrestrial Flora Survey o Initial walk through the site to determine the appropriate survey methodology to be used o Habitat general description (main vegetation type) o Survey plots for areas where trees cover more than 50% of the area to provide assessment of the main vegetation composition o Compile checklists for all plant species encountered during the field survey, with identification of all vascular plants to species level
The survey team comprised Toeolesulusulu Cedric Schuster performing both the plant and bird surveys with assistance provided by labourers for track clearing and local knowledge of the area. The terrestrial flora and fauna assessment were only carried out within the Vaisigano Watershed area of the Apia Catchment side of the Apia Catchment KBA. Five survey locations which classified into two separate categories. These are
1. The project area of influence (project site and East Alaoa and upper catchment) : a. the site for the proposed dam, b. Inundated zone and construction footprint c. Surrounding areas of the construction footprint that could be impacted by the project
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Figure 1: Survey locations
6. 2. Literature Review
6.1 2.1 Samoa’s Biodiversity Samoa’s biological environment reflects a rich natural heritage of high species diversity and endemism. It is estimated that Samoa supports 775 native vascular plant species of which approximately 30% of the angiosperms are endemic. There are about 280 genera of native angiosperms (more than any other archipelago in Polynesia). In addition, there are about 250 introduced plant species and 47 threatened plants. Samoa’s fauna consists of 21 butterfly species, 11 species of reptiles, 43 resident bird species eight of which are endemic, and three flying fox species. (Samoa NBSAP 2001)
This biodiversity constitutes an essential aspect of the Samoan culture, with many cultural proverbs and oratory traditions derived from or reflecting relationships with the forests, reefs, marine life and land animals.
The smallness and geographical isolation of Samoa’s islands from continental landmasses resulted in the high level of species endemism. At the same time, the same factors provide the seeds for its ecological fragility and vulnerability. For instance, many species have limited defenses against aggressive invasive species, and while endemism is high at the species level, it is less diversified at higher taxa levels. Genetic variability is thus limited.
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The ecological vulnerability inherent in its smallness, isolation, and limited genetic variability is exacerbated by the ever-present threat of natural events such as cyclones, climate variability, and the impacts of human activities.
6.1.1 2.1.1 Terrestrial Biodiversity Samoa’s NBSAP classified 19 terrestrial ecosystems based on Pearsall and Whistlers Ecosystem Mapping Survey of 1991. From the 19 ecosystem types, the Samoa NBSAP combined them into 5 common vegetation types, which are littoral vegetation, swamp and herbaceous marsh, rainforest, volcanic vegetation, and secondary or disturbed forest.
Samoa was once completely covered by indigenous lowland and upland rainforests with wetlands mostly along the coastal areas and mixed upland swamp forest. Since the mid 1800’s when commercial farming operations were introduced, the native forests primarily on the western side of Upolu were cleared for coconut and rubber tree plantations. Agricultural development since independence in the 1960’s provided another push in forest clearing as forests made way for plantations, farms and logging operations throughout the whole country. In the early 1990’s, major cyclones of Ofa in 1990 and Val in 1991 decimated the remaining indigenous forest stands to the point that the majority of Samoa’s forest is a mixture of secondary growth and disturbed forests. Upland Savaii’ montane and cloud forests were able to recover from the cyclones and remain the only undisturbed native forest left in Samoa while all the forest on Upolu Island has been affected in some way.
A few locations on Upolu such as the Uafato-Tiavea forest have remained pristine with limited disturbance from cyclones, while the rest of the upland forests are now a mixture of native plants mixed with invasive plants such as Merremia spp, Albizia spp, and rubber trees of Funtumia elastic and Castillo a elastica, and Sapthodea Campanulata.
6.1.2 2.1.2 Birds of Samoa Samoa’s land bird fauna is well studied. The first written records of bird observations in Samoa date from 1838 when the first bird species list for Samoa was prepared by the United States Exploring Expedition (Wilkes 1845). This was followed by a detailed description of birds as well as their cultural importance in Kramer’s History of Samoa Volume 2.
Since then numerous amateur and professional ornithologists have recorded their observations of the birds of Samoa and a number of manuals, field guides and reports on the birds of Samoa or of the South West Pacific have been written. In addition, numerous national and local biological surveys and assessments have included bird survey elements. A national bird survey conducted in 2006 culminated in the preparation of species recovery plans for the manumea (Tooth-billed Pigeon (MNRE 2006a) and the Ma’oma’o (Ma’o) (MNRE 2006b).
Despite the significant body of knowledge on Samoan land birds there is still limited knowledge of Samoan bird ecology and behaviour. Another major gap is the status of the seabird fauna of Samoa.
Currently, 81 bird species have been recorded in Samoa; this includes 31 breeding native land birds, one possibly extinct native land bird (the Samoan Moorhen), 4 breeding introduced birds, approximately 10 breeding seabirds and 35 migrants or vagrants. Nine of the land birds are endemic to Samoa and another 7 are regional endemics or near endemics.
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An unknown number of bird species have been extirpated since human arrival in Samoa, but fossil evidence from other islands in the region indicates that it may be very significant (e.g. see Steadman 1995).
6.1.3 Land Bird Species of Concern Samoa and American Samoa form the Samoan Island EBA 203 as defined by Birdlife International. Within the Samoan Islands EBA, 20 bird species are identified as having restricted range, making it important as trigger species for conservation efforts for the establishment of Important Bird Areas. Of the 20 restricted range species for the Samoa EBA, 19 are found in Samoa. Six of these, (together with Bristle-thighed curlew - a wide-ranging but scarce shorebird), are also considered to be globally threatened based on surveys and assessments over the last 20 years using IUCN Red List criteria (BirdLife International 2003). All the land bird species classified as globally threatened are endemic at least to the sub- species level to Samoa.
Samoan Moorhen (Gallinula pacifica): The Samoan Moorhen is classified as Critically Endangered although it has not been recorded in Samoa for over 100 years, apart from an unconfirmed sighting in the 1980s in upland forest west of Mt Elietoga.
Tooth-billed Pigeon (Didunculus strigirostris): The Tooth-billed pigeon is classified as Critically Endangered. Of the surveys conducted and recording documented, the tooth-billed pigeon is present in only a few locations and only in few numbers where they range from one to 20 birds recorded. The main threat to the tooth-billed pigeon is the diminishing of its main habitats due to land clearing and forest conversion along with predation from cats and rats. The tooth-billed pigeon is not specifically hunted but has been reported to be shot accidentally by hunters. Mao (Gymnomyza samoensis): the Mao is another of Samoan endemic birds identified as Endangered on the IUCN Red list. The 2006 review further confirms this as it is recorded in very few areas and populations recorded from these areas usually number below 10 in each site. The Mao was once found throughout the country but is now only confined to higher altitude areas away from settlements due to the loss of habitat and predation from cats and rats.
Shy Ground-dove (Gallicolumba stairi): the shy ground dove is classified as globally vulnerable. Nationally it is considered the most endangered of Samoa’s native land birds due to its being present in only very few numbers and recorded from less than 5 sites nationally. The main cause of concern for the Shy Ground dove it that it is a mostly ground foraging bird, thus making it vulnerable to predation from cats and rats. The decreasing availability of forest cover further limits the Shy Ground dove’s habitat.
Samoan Flycatcher (Myiagra albiventris): The Samoan Flycatcher global status is classed as Vulnerable. The population was severely impacted by the Cyclones that devastated Samoa in the 1990’s as was recorded by Parks, et, al (1992) and Schuster, et al (1997). Nevertheless, in the recent field surveys for the IBA report, the Samoan Flycatcher was found to be in very healthy populations not only IBA sites visited, but recorded regularly around the country in all locations including close to homes. Of the IBA sites surveyed, the Samoa Flycatcher was recorded in the range of 20-30 birds, furthermore, informal observations along other sites
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including along the roadsides and near homes, all yielded densities of over 2 per count. This is a good indication that the population is recovering.
Samoan White-eye (Zosterops samoensis) The Samoan white-eye, globally classed as Vulnerable, is found only on the uplands of Savaii at heights of above 800m. Due to limited surveys into the uplands of Samoa, the Samoan white-eye has not been well studied or recorded. But the recordings from the uplands of Savaii (Schuster et al, 97) approximates the populations to over 500, based on the recordings of over 50 birds on the north western part of Savaii and over 30 along the Salailua upland forest.
In addition, the Samoan Triller (Lalage sharpei) is classed globally, as Near Threatened. This was once a common bird in the forests of Samoa, but due to loss of habitat is now restricted to upland forests of Upolu and Savaii. Recording and sightings of this bird are only from a few locations and in numbers ranging from 1 to 5 at any one sight.
In addition to these, there are another 12 species that are globally considered to be Restricted Range species, but not classed as of immediate conservation risk., Finally six species are considered to be of national conservation concern as determined through the National Biodiversity Strategy and Action Plan. IBAs within a country are selected to provide at least 1, preferably more, sites that contain an assemblage of these Restricted Range species. 4 of these species are also considered to be national conservation concern while the remaining 2, island thrush and scarlet robin, are included below but were not used as IBA trigger species.
Figure 2. below shows the status of these 21 Samoan land bird species of global or national conservation concern, along with an indication of which are IBA trigger species.
Table 1: Status of Samoa's Land Birds of Concern NO SPECIES STATUS IBA Trigger Common Name Scientific Name Samoan Name species (Yes/No) 1 Samoan Moorhen Gallinula pacifica Puna’e CR/RR Yes 2 Shy Ground-dove Gallicolumba stairi Tuaimeo VU/RR Yes 3 Many-coloured Fruit-dove Ptilinopus perousi Manuma RR/cc Yes
4 Purple-capped Fruit-dove Ptilinopus porphyraceous Manutagi RR Yes 5 Tooth-billed Pigeon Didunculus strigirostris Manumea CR/RR Yes 6 Blue-crowned Lorikeet Vini australis Segavao RR/cc Yes 7 Flat-billed Kingfisher Todiramphus recurvirostris Tiotala RR Yes 8 Wattled Honeyeater Foulehaio carunculatus I’ao RR Yes 9 Ma’o Gymnomyza samoensis Ma’oma’o EN/RR Yes 10 Cardinal Myzomela Myzomela cardinalis Segasegamauu RR Yes 11 Polynesian Triller Lalage maculosa Mititai RR Yes 12 Samoan Triller Lalage sharpei Mitivao NT/RR Yes 13 Samoan Whistler Pachycephala flavifrons Vasavasa RR Yes 14 Samoan Fantail Rhipidura nebulosa Se’u RR Yes 15 Samoan Flycatcher Myiagra albiventris Tolaifatu VU/RR Yes 16 Scarlet Robin Petroica multicolor pusila Tolaiula cc No 17 Samoan White-eye Zosterops samoensis Matapapa’e VU/RR Yes
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18 Samoan Starling Aplonis atrifusca Fuia RR Yes 19 Polynesian Starling Aplonis tabuensis Fuiavao RR/cc Yes 20 Island Thrush Turdus poliocephalus Tutumalili cc No 21 Red-headed Parrotfinch samoensis Sega‘ula RR/cc Yes Erythrura cyaneovirens Legend:++
CR Critically endangered ‘…it is facing an extremely high risk of extinction in the wild in the immediate future, judged to be a probability of 50% in 10 years’ EN Endangered ‘. .it is not Critical but is facing a very high risk of extinction in the wild in the near future, judged to be a probability of 20% in 20 years.’ VU Vulnerable ‘. ..it is not Critical or Endangered but is facing a high risk of extinction in the wild in the medium-term future, judged to be a probability of 10% in 100 years.’ NT Near threatened does not qualify for Critically Endangered, Endangered or Vulnerable now, but is close to qualifying for or is likely to qualify for a threatened category in the near future. RR Restricted Range ‘… species not considered to be under immediate conservation threat, but with a restricted range, ie with world distributions less than50,000 km2. These species are all identified as representative of the Samoan Endemic Bird Area. c Conservation concern ‘… a national category for native species that are of local conservation concern even though they may not be considered to be globally threatened. This category includes native birds that may be regionally common but are locally rare and believed threatened in Samoa. ‘
Sea/shore birds Based on the available literature, approximately 12 seabird and shorebird species that are of global or national conservation concern have been recorded in Samoa (see table 2).
The globally threatened Bristle-thighed Curlew Numenius tahitiensis is a regular northern winter migrant in small numbers. Several seabird species of global concern are either passage migrants, visitors or status unknown in Samoa. These include the Phoenix Petrel Pterodroma alba; Tahiti Petrel Pseudobulweria rostrata; Collared Petrel Pterodroma brevipes and Polynesian Storm Petrel Nesofregetta fuliginosa. Recent surveys in American Samoa have recorded the Tahitian petrel, Audubon’s shearwater Puffinus iherminieri and possibly the Wedge-tailed shearwater Puffinus pacificus and Phoenix petrel as breeding on Lata Mountain on Ta’u (O’Connor and Rauzon 2004). Further survey work, and estimates of the number of breeding birds present, is required to get a better understanding of the status of these and other seabirds in Samoa. No IBA sites have been identified, to date, for these species in Samoa.
Table 2:Status of Samoa Sea Birds of Concern
NO Common Name Scientific Name Samoan Name STATUS Phoenix Petrel Pterodroma alba EN
Collared Petrel Pterodroma brevipes NT Tahiti Petrel Pseudobulweria rostrata NT
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1 Polynesian Storm-petrel Nesofregatta fuliginosa Ta’I’o VU 2 Red-Tailed Tropic Bird Phaethon rubricauda Tavaeula cc 3 Masked Booby Sula dactylatra Fuao cc 4 Great Frigatebird Fregata minor Taio cc 5 Lesser Frigatebird Fregata ariel Taio cc 6 Crested Tern Sterna bergi Gogo cc 7 Sooty Tern Sterna fuscata Gogo cc 8 Black- Naped Tern Sterna sumatrana Gogo cc 9 Bridled Tern Sterna anaethetus Gogo Uli cc 10 Blue Noddy Procelsterna cerulea Laia cc 22 Black Noddy Anous minutus Gogo cc Bristle-Thighed Curlew Numenius tahitiensis Tuliolovalu VU Legend:++ EN Endangered ‘. .it is not Critical but is facing a very high risk of extinction in the wild in the near future, judged to be a probability of 20% in 20 years.’
VU Vulnerable ‘...it is not Critical or Endangered but is facing a high risk of extinction in the wild in the medium-term future, judged to be a probability of 10% in 100 years.’ NT Near-threatened does not qualify for Critically Endangered, Endangered or Vulnerable now, but is close to qualifying for or is likely to qualify for a threatened category in the near future.
‘… a national category for species that are of local conservation concern even though Conservation they may not be considered to be globally threatened. This category includes cc concern seabirds that breed in Samoa that may be regionally common but are locally rare and threatened in Samoa. ‘ 6.2 2.2 Vaisigano Watershed: Natural Habitat The ecology of the Vaisigano catchment was originally classified as part of the lowland rainforest and ridge rainforests while above 500 m it merges into upland forests and montane forest.
• Rainforest: lowland and upland: Lowland rainforests extend from the coast all the way up to around 600m altitude throughout the country. For the Vaisigano area, the forest would have been dominated by Pometia pinata (tava) and Dysoxylum samoenses (maota) but with a rich diversity of other forest trees and undergrowth. • Ridge rainforests/Riparian has similar vegetation to rainforests with very rich diversity although interspersed along the ridges and streambeds are tree species are specific riparian tree species such as Barringtonia samoenses (falaga) and Inocarpus fagifer (ifi; Tahitian chestnut). This ecosystem is usually had high density and diversity of tree climbing vines and epiphytes. • Upland Forest: Forest above 600m is typically classified as Upland and Montane Forests. These forest areas are dominated by Dysoxylum huntii (maota mea) with other typical upland and montane forest trees such as s Reynoldsia lanutoensis and Fagraea berteroana with a high density and diversity of epiphytes.
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The ecosystems and habitats of the area started changing when it was originally cleared around the Alaoa area during the establishment of the water reservoir and later the hydro power plants at Alaoa and Fale o le Fee in the late 1970s. Around the same time, families from Maagiagi and Vailima started clearing some of the lands along the riverbanks for plantations. To date, several new and old plantations are still present along the riverbed and the ridges along the project influence zone. Cyclone Ofa in 1990 and Cyclone Val in 1991 brought about a dramatic change in the composition of the indigenous forests as many of the trees along the riverbanks and the ridges fell and were later replaced by fast growing alien invasive species such as Albizia falcataria, and rubber trees Funtumia elastica and Castilla Elastica. The spread of the taro blight from around 1993 meant most of the areas cleared for taro plantations were left fallow and were quickly converted into secondary forests dominated by the alien invasive trees. Cyclone Evan in 2012 and Cyclone Gita in the beginning of 2018 brought about major flooding within the Vaisigano River leading to landslides along the ridges and further destruction of the secondary forest in the area to what the area is now widely open dominated by vines and shrubs and fastgrowing invasive rubber trees. For the Upland Forest of the Vaisigano Watershed Area, the forest damage from Cyclone Ofa and Cyclone Val in 1990 and 1991 has changed the make up to what is now predominantly covered by dense thickets of the native invasive shrub Cestrum nocturnum with some of the big forest trees interspersed along the area. Part of the top end were also replanted through a watershed regeneration program in the late 1990’s and presently mostly with native tree species.
6.3 2.3 Apia Catchment Key Biodiversity Area The PAI is located within the wider Apia Catchment KBA and shown in Figure 2. The total Apia Catchment KBA area is 8,336 ha while the proposed inundated zone within the PAI is slated to cover only 20ha. The Vaisigano Watershed is one of three main watersheds in what has been identified as the Apia Catchment Key Biodiversity Area in the Samoa National Biodiversity Strategy and Action Plan. The Fuluasou and Leafa watersheds lie on the west of the Cross-Island Road. Along with the main watersheds, the Apia Catchment KBA also includes the only legally protected area which is the MT Vaea Scenic Reserve and Robert Louis Stevenson Memorial Reserve. The MT Vaea Scenic Reserve is outside the project area of influence The Apia KBA is not a legally protected area but has been identified in the NBSAP as amongst the important area for biodiversity conservation. The Apia Catchment KBA especially in the higher elevation of above 600m is where most of the data presently available recognises as being an area having high biodiversity and hold important ecological services functions such as water supply for the upper-catchment where there is limited to no direct human intervention. Within this higher elevation area, most of the critically endangered flora and fauna of Samoa have been recorded over the past. These include, a good population of the critically endangered Tooth-billed pigeon (Manumea), the presence of the threatened Mao, and the Samoan Ground Dove, birds as well as some of the other near threatened bird such as the Samoa Triller, the Samoan Robin, and the Red-Headed parrotfinch. Furthermore, some recent expeditions into the top of the Apia Catchment FBA has found threatened Samoan native palm.
“Certain areas of the KBA/IBA such as the Mt Vaea Nature Reserve, Lake Lanutoo National Park and Upper Vaisigano Watershed area have been well surveyed by different groups. From these surveys, populations ranging in the 20s to 30s of the globally threatened Tooth-billed Pigeon and Mao have been recorded. Other trigger species such as the Samoan Flycatcher, Samoan Triller, Many coloured fruit dove and Polynesian Starling were also recorded in good densities. Population densities for the Red-headed Parrotfinch were the highest in this site during the IBA field survey” (Schuster, 2010).
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Table 3: Apia Catchment Key Biodiversity Area
Site Name Island Current Protection Threats e # Faipule Approximate Status IBA Terrestrial Trigger District Area (Ha (Y/N) Species in Site
5 Apia Upolu Vaimauga 8336ha Partly protected in Lake y Samoan Bush Invasive catchment west, Lanoto’o National Park Palm (Niu vao), species, Faleata, and Mt Vaea Scenic Tooth-Billed hunting, Siumu Reserve. Some Pigeon development conservation effort by (Manumea), MNRE’s watershed Ground Dove management section (Tuaimeo), Mao (Maomao), Samoan Broadbill (Tolaifatu), Samoan Flying Fox (Pea vao), Thaumatodon hystricelloides (Sisi) Source: (CI, 2010) Fortunately for the proposed Alaoa Multipurpose dam, which is located at the bottom of the Apia KBA, as well as being of much lower altitude of between 190-260m, the vegetation and quality of the habitat has undergone substantial transformation over the years from cyclones and human intervention, it is unlikely that any of the threatened biodiversity would exist in the PAI as a permanent residence. It is quite possible that the area would be use as a transient site while moving around the forested areas of the KBA. Figure 2: Apia Catchment Key Biodiversity Area
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7. 3. Survey Results 3.1 Project Area of Influence:
7.1 3.1.1 Construction Footprint and Inundated Zone
The project area of influence as shown in Figure 3 is located within the Vaisigano Watershed Area which is one of the three main Watershed Areas in the Apia Catchment Key Biodiversity Area shown in Figure 2 which totals over 8,336ha. The Vaisigano Watershed Area extends from 220 m to over 1000 m elevation while the construction footprint will be located at the bottom end of the catchment at around 160 mASL with the upstream extending at approximately 240 mASL.
Figure 3:Project Area of Influence
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The assessment found that much has changed in the make-up of the vegetation and ecosystems in the Vaisigano Watershed as shown in the Table 1.
Table 4: Ecosystem Types within the Survey sites Location Ecosystem Types Project Non-native vegetation Influence This area has been heavily influenced by human intervention through clearing Zone for plantations leading to several patches of fallow lands along with existing plantations. Additionally, the impact of natural events such as cyclones and floods have also contributed to modify the previously lowland and ridge rainforest area to where now a few patches of forested areas are
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predominantly covered by invasive trees mixed with secondary forest trees and some remaining native forest trees.
Maagiagi: Non-native vegetation: this area is classified as settlements which includes residences, family plantations and some fallow lands. In some of the fallow lands, secondary forest is mixed with alien invasive species.
Alaoa Non-native vegetation: this is highly modified as reflected by the dominance of secondary forest mixed and alien invasive species despite the appearance of a closed forested area. Plantations and fallow lands are also common along this site. 7.2 Terrestrial Flora
The terrestrial flora surveys positively identified over 45 plant species although a few more of the undergrowth plant species could not be identified due to accessibility along the steep ridges. Of the species identified 15 were native species of trees of lowland rainforest and secondary forest ecosystems, and tree ferns common in mid altitude forests, and 5 alien invasive trees. Five varieties of food crops were identified growing in plantations and some fallow lands. The rest of the vegetation was made up shrub, weeds, vines and epiphytes. Typical vegetation in the PIA site and its immediate surrounding area shown in Plates 1-4 illustrate that the area has been modified over many years due to human clearings for plantations and from natural events such as cyclones and floods. The vegetation composition of the area is now predominantly open fallow areas which are covered by invasive vines Mikania micrantha (mile-a-minute) and Merremia peltata. In the areas where trees remain along the river edge, and the some of the ridges, they are primarily dominated by the alien invasive rubber trees Castilla elastica, Funtumia elastica and tamaligi Albizia falcataria. Native secondary native forest trees such as Hibiscus tiliaceus (fuafua), Kleinhovia hospita (fau), Cananga odorata (mosooi), Erythrina variegate gatae and Trema cannabira magele were present.
In open fallow lands, the vegetation is predominantly plantation crops of taro and banana with some taamua, ava, cocoa and coconut trees also present. In old plantation sites, the vegetation is covered by mile a minute and Merremia vines alongside weeds
Remnants of the original lowland and ridge rainforest species such as Pometia pinata (tava) and Dysoxylum samoensis (maota) which once dominated this forest type, are now only found scattered along the area and mostly along the ridges, due to plantation clearings, cyclones and floods.
Plates 1: Fallow lands at the proposed inundated area
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Plates 2: fallow and plantation lands mixed with invasive tree dominated forest
Table 5: Plant list for Project Influence Area Scientific Name Samoa/Common name Use Dominance Adenanthera pavonina lopa Alien Invasive 3% Alibizia falcatera tamaligi paepae Alien Invasive 26% Biscofia javanica o'a/mulberry tree Ornamental - breadfruit Artocarpus spp Food crop -
Cananga odorata mosooi Ornamental 4% Castilla elastica pulu mamoe/ rubber Invasive 20% tree Cocos nucifera Niu/coconut Food crop - Cordyline terminalis Ti Native shrub - Cestrum nocturnum teine o le po Native invasive - Clidemia hitra Lapiti/ Kusters curse Alien invasive -
Collocasia spp taro Food crop - Cyathea lunulata Olioli/tree fern Native 1% Erythrina variegata gatae Alien legume tree - Ficus scabra mati Native -
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Flueggea flexuosa poumuli Timber tree - Funtumia elastica pulu vao Alien invasive 13%
hibiscus tiliaceus fau Secondary forest tree - Kleinhovia hospita fu'afu'a Secondary forest tree 3% Laportea photiniphylla Salato Secondary forest tree 1% Macropiper puberulum ava Native crop - manihot esculenta manioka Food crop - Morinda citrifolia nonu ornamental -
Musa spp banana Food crop - Neonauclea fosteri Afa Native forest tree - Passiflora luarifolia pasio vao Invasive - Planconella garberi Gasu native forest tree 2% Plqnconella torricellensis mamalava Native forest tree 2% Pometia pinata Tava Native forest tree 17%
Rhus taitensis tavai Secondary forest tree 6% Schizostachyum Bamboo / ofe Forest tree - glaucifolium Scientific Name Samoa/Common name Use Dominance Sida parviflora mautofu Invasive weed - Spathodea campanulata faapasi Alien invasive - Theobroma cacao cocoa Food crop -
Terminalia glabrata Talie Native tree - Trema cannabina magele Native shrub -
West Alaoa stream: The area is predominantly open along the river bed due to clearing for plantations and remnants of fallen trees from cyclones and floods. The vegetation is old plantation with regrowth made up of invasive pulu and tamaligi trees along with some secondary and mature forest trees.
Along the ridges in areas where recent landslides had occurred, these are predominantly covered by ground ferns, vines and shrubby vegetations. In areas with no signs of landslides, the vegetation is a mixture of invasive pulu trees, tamaligi trees, native mature and secondary forest trees.
East Alaoa stream The riverbed area has predominantly been cleared for plantations as evident by the old banana and taro plantations in open areas. The large trees along this area the invasive pulu and tamaligi trees with few large native mature forest trees tava, mamalava, afa, and maota along with some secondary forest trees such as tavai, fuafua, mossoi.
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The steep ridges along this end which had not been cleared for agriculture are still dominated by native mature forest species of tava and maota.
7.3 Bird Survey
Twenty bird species were recorded within the PAI which included 3 alien invasive species, three species of sea birds, 14 native land birds (refer to Table 7). The invasive myna birds were the most common birds in this site with native Samoan Starling, and Wattled Honeyeater also present in good numbers along with the banded rail along the stream bed. These birds are common to open areas where food sources such as insects and nectars from the shrubs, weeds and secondary forest trees are accessible. Additionally, with such birds not being hunted, they have adapted to surviving with regular human presence. Brown Noddy and white terns were also very commonly seen nesting and living on the top of native forest trees within the proposed inundated zone and at the top of the ridges. Pacific pigeon and fruit doves were also heard in and around the PAI. These birds normally move around regularly so they are not confined to smaller areas, so will not be much affected by the activities of the project apart from possibly being hunted by workers during the construction period.
Additionally, the Manumea and Maomao, the two birds listed as Critically endangered and endangered were not found during survey. They had not been recorded in this area in previous studies undertaken, including the recent ADB studies for the Alaoa HPP Initial Environmental Examination in 2013. As noted in this study and previous assessment, including the IUCN Red List assessment, the Manumea and Maomao are unlikely to inhabit ecosystems which have been modified through human interventions such as the proposed project influence area
3.1.2 Maagiagi and Alaoa West:
7.4 Terrestrial Flora
The flora assessment identified around 28 plant species in this site, of which 6 were food crops, 5 invasive species, 12 native lowland rainforest and secondary forest trees along with 27 shrubs, vines and epiphytes. No plant species of concern were identified in these sites
The Maagiagi and Alaoa West sites which border the construction footprint on both the west and east include Maagiagi village settlement, plantation crops such as taro, bananas, cocoa, coconuts, and fruit trees. Along the ridgelines, certain areas had been cleared for plantations while others are now fallow lands. Areas that had not been cleared are dominated by alien invasive rubber trees Castilla elastica, Funtumia elastica, alibizia trees with secondary forest trees and shrubs such as Hibiscus tiliaceus, Kleinhovia hospita, Cananga odorata Erythrina variegate and Trema cannabira interspersed with some remaining native lowland rainforest trees. In open and fallow areas, the vegetation is predominantly covered by the invasive vines Mikania micrantha and Merremia peltata dominate.
Overall, both sites on the west and end boarders of the construction are identified a highly modified habitats based on the plants present and that no native plants of conservation concern were found. Additionally, these sites are unlikely to be returned its original ridge rainforest ecosystem without human assistance in the form of a replanting program. Plates 3: Alaoa: fallow lands and invasive species:
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Plates 4: Alien invasive species dominated ridges
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Table 6: Plant list for Maagiagi and Alaoa sites Scientific Name Samoa/Common name Use Dominance Adenanthera pavonina lopa Alien Invasive 3% Alibizia falcatera tamaligi paepae Alien Invasive 30% Biscofia javanica o'a/mulberry tree Ornamental -
breadfruit Artocarpus spp Food crop - Cananga odorata mosooi Ornamental 5% Castilla elastica pulu mamoe/ rubber Invasive 22% tree Cocos nucifera Niu/coconut Food crop - Cordyline terminalis Ti Native shrub - Cestrum nocturnum teine o le po Native invasive -
Clidemia hitra Lapiti/ Kusters curse Alien invasive - Collocasia spp taro Food crop - Cyathea lunulata Olioli/tree fern Native 1% Erythrina variegata gatae Alien legume tree - Ficus scabra mati Native - Flueggea flexuosa poumuli Timber tree -
Funtumia elastica pulu vao Alien invasive 17% hibiscus tiliaceus fau Secondary forest tree - Kleinhovia hospita fu'afu'a Secondary forest tree 3%
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Laportea photiniphylla Salato Secondary forest tree 1% Macropiper puberulum ava Native crop - Scientific Name Samoa/Common name Use Dominance manihot esculenta manioka Food crop - Morinda citrifolia nonu ornamental - Musa spp banana Food crop -
Neonauclea fosteri Afa Native forest tree - Passiflora luarifolia pasio vao Invasive - Planconella garberi Gasu native forest tree 2% Plqnconella torricellensis mamalava Native forest tree 2% Pometia pinata Tava Native forest tree 10% Rhus taitensis tavai Secondary forest tree 6% Schizostachyum Forest tree - glaucifolium Bamboo / ofe Sida parviflora mautofu Invasive weed - Spathodea campanulata faapasi Alien invasive - Theobroma cacao cocoa Food crop - Terminalia glabrata Talie Native tree - Trema cannabina magele Native shrub - 7.5 Bird Survey
Maagiagi area. The Maagiagi village settlement site which is where human settlements and plantations are located had the least diversity with only 16 bird species including four alien invasive bird species. The most common birds in this site were the Myna birds, the Samoan starling and the Red Vented Bulbul. The site also had the lowest diversity while the highest density of birds which were made up of mostly the alien invasive myna birds and red-vented bulbuls. Alaoa west area. The Alaoa site, although disturbed forest and dominated by exotic trees, it recorded the highest bird diversity of the sites around the project area of influence. This is primarily due to less human disturbances on its western borders. Five counts were conducted in this site along the ridge starting from the existing Alaoa Headpond and extending along the water channel that leads to the headpond. A total of 24 bird species were recorded at this site which included three alien invasive birds, three sea bird species and 16 native bird species. The site was significant in that bird calls from both the Maomao and Tooth-billed pigeon were heard although they were far away, and along steep terrain so could not be seen. The most common birds in this site were the Samoan Starling, the Wattled Honeyeater and the Samoan Whistler. Although the Myna birds were heard, they were predominantly around the Alaoa headpond.
The bird surveys further support this assessment as the invasive myna birds along and nectar feeding native birds such as the honeyeaters, and starlings dominate the landscape especially in open areas.
Table 7: Bird Survey List in Project Area of Influence Common name Scientific names Conservation Habitat/range Project Site Alaoa Maagiagi Status
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Introduced birds Common Myna/ Acridotheres tristis Inv Open areas/low to mid y y y maina altitude Jungle Myna/ maina Acridotheres fuscus Inv Open areas y y y
Red-vented Bulbul/ Pycnonotus cafer Inv Open areas y y y manu palagi Feral Pigeon/ lupe Columba livia Inv Open areas n n y
palagi Native birds Pacific Pigeon /Lupe Ducula pacifica Vu Mature forest White-throated Columba vitiensis Vu Mature forest n n n Pigeon/ fiaui White-rumped Aerodramus spodiopygius LC caves Swiftlet/ peapea y y y
Wattled honeyeater/ Foulehaio carunculata LC Open areas y y y iao Didunculus strigirostris CR Mature forest n y n Tooth -billed Pigeon/ manumea Petroica pusilla Vu Mid-high altitude Scarlet Robin/ tolai y n n Samoan Whistler/ Pachycephala flavifrons NT montane y y n vasavasa NT montane n n n Samoan Lalage sharpei
Triller / miti vao Aplonis atrifusca LC Open area y y y Samoan Starling/ fuia Samoan Myiagra albiventris NT undergrowth n y n Broadbill/tolaifatu Samoan Fantail/seu Rhipidura nebulosa LC Open areas y y y Red-headed Erythrura cyaneovirens Vu Mature forest n y n parrotfinch/ Purple-capped Ptilinopus porphyraceus Vu Mature forest Fruitdove y y y /manutagi Purple Swamphen/ Porphyrio melanotus NT Swampy areas y y n manualii Lalage maculosa LC Open areas y y y Polynesian Triller/ miti Polynesian Starling/ Aplonis tabuensis NT Forest areas n n n mitivaoMao/ Gymnomyza samoensis En montane n y n maomao Many-coloured Ptilinopus perousii Vu Mature forest n y y Fruitdove/ manuma Flat-billed Kingfisher/ Todirhamphus LC Open areas y y y tiotala LC Open areas Cardinal recurvirostrisMyzomela cardinalis honeyeater/ y y y segasegamauu Blue-crowned Lory/ Vini australis Nt Forest and open areas y n n segavao Tyto alba LC Open areas n n n Barn Owl/ lulu Banded Rail /vea Gallirallus philippensis LC Open areas y y y Pacific golden plover Pluvialis fulva LC Open areas n n n /tuli Vu Mature forest n n n Friendly Ground- Gallicolumba stairi dove/ tuaimeoSamoan Gallinula pacifica n n n
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Moorhen/punae Seabirds White Tern/ gogo Gygis alba LC Forest tree tops y y y sina White-tailed Tropic- Phaethon lepturus LC Forest tree tops y y n birdBrown Noddy Anous stolidus LC Forest tree tops y y y tava'e sina/ gogo uli Tahiti Petrel/ taio Nesofregetta fuliginosa LC Forest tree tops n n n
Totals 19 22 16 Key: Cr: critically Endangered: En-endangered Vu: vulnerable; NT: ne9ar threatened; Inv-Invasive species 7.5.1 3.1.3 Terrestrial Mammals Samoa only has 3 species of native mammals which are the 2 fruit bat species and 1 long sheathtailed bat. The survey only observed Pteropus tonganus Tongan fruit bats flying around, but no roost was seen within the project area of influence. A fruit bat roost is suspected further up in the catchment area as evident in fruit bats seen at dusk flying high above the PAI. The condition of vegetation within the project area of influence being that of a highly modified habitat makes it not an ideal place for a fruit bat roost to be in existence as these normally occur in mature forest and away from human occupation. None of the introduced mammals were seen except pig tracks were noticed during the surveys.
7.6 3.2 Outside the Project Area of Influence
3.2.1 Fale ole Fee and Upper Vaisigano Catchment
7.6.1 Terrestrial Flora The Vaisigano Upper-catchment and Fale o le Fee sites are outside the PIA but within the Apia Catchment KBA, thus they were assessed as for their ecological values to native flora and fauna. The PIA will affect less than 2 % of the total Apia Catchement KBA area of 8,336 ha. The sites were located at the top end of the ridge rainforest reaches at just below 600 m elevation. They were surveyed to provide an assessment on the condition of the forest for natural regeneration and as important site for birds. Specifically, the existing hydropower plant at Fale o le Fee site in the upper east branch of Vaisigano River and the upper Alaoa river branch as shown in Figure 1. The survey focussed more on the tree species of which it was able to identify 55 plant species. Of these, 8 were classified as invasive species. The survey found that both the Fale o le Fee and Upper Alaoa catchment sites had over 70% forest cover which are dominated by native trees Pometia pinata and Dysoxylum samoenses. Other native forest trees such as Planconella samoenses, Planconella garberi, Syzygium inophylloides Macaranga stipulosa were relatively common while the undergrowth has typical native forest vegetation such as Cananga odorata, Fagraea sp, Myristica fatua, Cyathea affinis and Niuvao. The native timber trees and much of the native flora in the area are very important for their ecosystem services such as soil retention, as well as the food for birds and native biodiversity. Along the stream bed edges were pockets of Inocarpus fagifer stands. Stands of the alien invasive Castilla elastica, Funtumia elastica and Albizia spp were interspersed within the forest canopy but have not overtaken the area compared to the lower catchment where the PIA will be located. The Invasive vine Mikania micrantha and the native vines Epipremnum pinnatum, Piper graeffei, and Macropiper puberulum also occurred amongst in the undergrowth, especially in open areas. Based on the status of the forest where it is still dominated by native forest trees, apart from areas that were damaged by cyclones and floods and with limited encroachment of alien species and almost no human intervention, the site is classified as natural habitat.
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The assessment did find not any threatened, vulnerable or critically threatened plant species of Samoa.
Table 8: Ecosystem types outside the project area of influence Location Ecosystem Types Fale o le Fee Ridge and Upland Rainforest:/Natural Habitat Upland rainforests extend to and Upper around 500m altitude throughout the country. For the Vaisigano area, the catchment forest in most areas is still dominated by Pometia pinata (tava) Planconella garberi and Dysoxylum samoenses (maota) but with a rich diversity of other forest trees and undergrowth. Along the ridge’s species such Inocarpus fagifer, can dominate in small pockets. Upland Forest/Natural Habitat: This area is still dominated by Dysoxylum huntii with other typical upland and montane forest trees such as s Reynoldsia lanutoensis and Fagraea berteroana. For the Vaisigano Watershed Area, the forest damage from Cyclone Ofa and Cyclone Val in 1990 and 1991 has changed the make up to what is now predominantly covered by dense thickets of the native invasive shrub Cestrum nocturnum with some of the big forest trees interspersed along the area. Part of the top end were also replanted through a watershed regeneration program in the late 1990’s and presently mostly with native tree species.
Plates 5: Fale o le Fee: undisturbed native forest
Plates 6: Upper Alaoa Catchment: Disturbed Native Forest
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Plate 7: Fale o le Fee: Cyclone damaged Riparian
Table 9: Fale o le Fee and Upper-catchment Plant List Scientific Name Local/common name Use Adenanthera pavonina lopa Alien invasive Alibizia falcatera tamaligi paepae Alien invasive Alphitonia zizyphoides toi Native timber tree Alyxia bracteolosa lau maile Native vine/ornamental Biscofia javanica o'a Native stree/ornamental breadfruit Artocarpus spp Food crop Cananga odorata mossoi Ornamental tree Canarium vitiense maali Native timber tree Castilla elastica pulu mamoe Alien invasive tree ccocs nucifera Niu/coconut Food crop Cestrum nocturnum teine o le po Native invasive shrub Clidemia hitra lapiti Alien invasive shrub
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Cordyline fruticosa ti vao Native/ornamental plant Cyathea lunulata olioli Native ferm Diospyros samoenses auauli Native timber tree Dysoxyllum maota maota Native timber tree Dysoxylum samoensis tufaso Native timber tree Elattostachys falcata taputoi Native timber tree Erythrina variegata gatae Legume tree Fagraea berteroana pualulu Native tree Faradaya amicorum mamalupe Native shrub ficus obliqua aoa Native tree Ficus scabra mati Native tree Flueggea flexuosa poumuli Native tree Funtumia elastica pulu vao Alien invasive tree Glochidion ramiflorum masame Native tree Heliconia spp laufao Native tree hibiscus tiliaceus fau Native secondary forest tree Inocarpus fagifer ifi Riparian forest tree Scientific Name Local/common name Use Kleinhovia hospita fu'afu'a Secondary forest tree Leucaena leucocephala lusina Alien invasive tree Macaranga harveyana lau pata Native secondary forest tree Macaranga stipulosa lau fatu Native forest tree Myristica fatua atone Native forest tree Neisosprema oppositifolia fao Native forest tree Neonauclea fosteri afa Native timber tree Nephrolepis hirsutula vao tuaniu Native ground fern Omalantus nutan fanuamamala Native shrub Passiflora luarifolia pasio vao Alien Invasive vine Piper graeffei Avaava aitu Native vine Piper macropiper fue manogi Native vine Piptrus argenteus soga Native shrub Planconella garberi ala'a Native timber tree Planconella torricellensis mamalava Native timber tree Pometia pinata Tava Native timber tree Psydrax merrillii ola sina Native shrub Psytoria insularum matalafi Native shrub Rhus taitensis tavai Native secondary forest tree Scaevola tacada toitoi Native tree
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Sida parviflora mautofu Alien weed Spathodea campanulata faapasi Alien invasive tree Sterculia fanahio fagaio Native tree Syzygium clusiifolium asi vai Native timber tree Syzygium inniphylloides asi toa Native timber tree Syzygium samoenses fena vao Native timber tree Trema cannabina magele Native shrub 3.2.2 Birds The Fale o le Fee and Upland had the most diversity and density of native birds. A total of 23 birds were observed including 3 sea birds and 20 native birds. The native birds recorded are all birds that predominantly live in mature forest habitats. Both the manumea which is critically endangered and the endangered maomao were present in these 2 sites. The Manumea was heard more than 3 times in each of the sites while only one Maomao was confirmed at the upper Alaoa site. The presence of both these endangered birds in the upper catchment confirms the importance of protecting the upper catchment site and coincides with the status of the forest being a natural habitat despite some damage from cyclones and floods. With areas covered by the survey being only a very small portion of the wider upper Vaisigano watershed area, it is likely that a few more manumea and maomao are likely to inhabit the areas with the forest being in healthy condition and a presence in good numbers of the maota and tufaso trees that are main food sources for the manumea. Table 10: Bird Surveys: Outside Project Area of Influence Common name Scientific names Conservation Habitat/range Fale o le Upper Status Fee Alaoa
Introduced birds
Acridotheres tristis Inv Open areas/low to n n Common Myna/ maina mid altitude Jungle Myna/ maina Acridotheres fuscus Inv Open areas n n Red-vented Bulbul/ manu Pycnonotus cafer Inv Open areas n n palagi Columba livia Inv Open areas n n Feral Pigeon/ lupe palagi Native birds Pacific Pigeon /Lupe Ducula pacifica Vu Mature forest y y Columba vitiensis Vu Mature forest y y White-throated Pigeon/ fiaui
White-rumped Swiftlet/ Aerodramus spodiopygius LC caves y y peapea
Wattled honeyeater/ iao Foulehaio carunculata LC Open areas y y Tooth-billed Pigeon/ Didunculus strigirostris CR Mature forest y y manumea Petroica pusilla Vu Mid-high altitude y y Scarlet Robin/ tolai Samoan Whistler/ vasavasa Pachycephala flavifrons NT montane y y Samoan Triller/ miti vao Lalage sharpei NT montane n y Samoan Starling/ fuia Aplonis atrifusca LC Open area y y Myiagra albiventris NT undergrowth y n Samoan Broadbill/tolaifatu Samoan Fantail/seu Rhipidura nebulosa LC Open areas y y
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Red-headed parrotfinch/ Erythrura cyaneovirens Vu Mature forest y y Manu ai paulaau Purple-capped Fruit-dove Ptilinopus porphyraceus Vu Mature forest y y /manutagi Purple Swamphen/ manualii Porphyrio melanotus NT Swampy areas n n Polynesian Triller/ miti Lalage maculosa LC Open areas y y Polynesian Starling/ mitivao Aplonis tabuensis NT Forest areas n y Mao/ maomao Gymnomyza samoensis En montane n y Many-coloured Fruit- Ptilinopus perousii Vu Mature forest y y dove/ manuma Flat-billed Kingfisher/ tiotala Todirhamphus LC Open areas y y Cardinal honeyeater/ recurvirostrisMyzomela LC Open areas y y segasegamauu cardinalis Blue-crowned Lory/ segavao Vini australis Nt Forest and open n y areas Barn Owl/ lulu Tyto alba LC Open areas n n Banded Rail /vea Gallirallus philippensis LC Open areas y y Friendly Ground-dove/ Gallicolumba stairi Vu Mature forest n n
tuaimeo Gallinula pacifica n n Samoan Moorhen/punae Seabirds
White Tern/ gogo sina Gygis alba LC Forest tree tops y y White-tailed Tropic-bird tava'e Phaethon lepturus LC Forest tree tops y y sina Anous stolidus LC Forest tree tops y y Brown Noddy / gogo uli Tahiti Petrel/ taio Nesofregetta fuliginosa LC Forest tree tops n n Pacific golden plover /tuli Pluvialis fulva LC Open areas n n
Totals 20 23 Key: Cr: critically Endangered: En-endangered Vu: vulnerable; NT: near threatened; Inv-Invasive species
4. Natural and Critical Habitat Assessment:
4.1 Habitat Definitions:
4.1.1 Modified Habitat Modified Habitat is defined in the ADB’s Social Safeguards Policy (2009) as land and water area’s that may contain a large proportion of plant and/or animal species of non-native origin, and/or where human activity has substantially modified an area’s primary ecological functions and species composition. In practice, natural and modified habitats exist on a continuum that ranges from largely untouched, pristine natural habitats to intensively managed modified habitats.
4.1.2 Natural habitat assessment Natural Habitat is defined in ADB’s Social Safeguard Policy (2009) as land and water areas where biological communities are formed largely by native plant and animal species, and where human activity has not essentially modified the area’s primary ecological functions (ADB 2009).
4.1.3 Critical habitat assessment Critical habitat is defined in ADB’s SPS (2009) as a subset of natural and modified habitat that includes:
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(a) habitat required for the survival of critically endangered or endangered species; (b) areas having special significance for endemic or restricted-range species; (c) sites that are critical for the survival of migratory species; (d) areas supporting globally significant concentrations or numbers of individuals of congregatory species; (e) areas with unique assemblages of species or that are associated with key evolutionary processes or provide key ecosystem services; (f) areas having biodiversity of significant social, economic, or cultural importance to local communities; (g) areas either legally protected or officially proposed for protection, such as areas that meet the criteria of the World Conservation Union classification, the Ramsar List of Wetlands of International Importance, and the United Nations Educational, Scientific, and Cultural Organization’s (UNESCO) world natural heritage sites.
7.7 4.2 Project Area of Influence: Modified Habitat
Samoa’s biodiversity although high in endemism is not as rich compared to other archipelagos and islands in the Pacific region. Over the years, much of the native forest especially the lowland ecosystems had undergone considerable changes due to human interventions through infrastructure development such as roads, dams, and human settlements including land clearing for plantations and natural events in the form of cyclones and floods. As such, much of the ecosystems close to human habitation including in and around the project area of influence are open areas, village settlements, fallow lands, and mixed disturbed forests.
The flora and fauna surveys in and around the project area of influence as reflected in Table 8 and Figure 5 confirms the area to be where human activity has substantially modified an area’s primary ecological functions and species and while the habitat is not required for the survival of critically endangered or endangered species, thus rendering it to be a modified habitat with very low ecological values. The riparian, and forested areas are dominated by invasive trees, vines and weeds, while native secondary and mature forest trees area present sporadically. Therefore, the project will not unduly impact the native biodiversity. Table 11: Ecological Values of habitats within the Apia Catchment KBA Habitat Unit Location relative to project components Ecological value Riparian/ Fallow Dam and reservoir Low lands/Plantations/ settlements Adjacent to reservoir, construction footprint, Low access road and downstream of dam Undisturbed forest, No interaction High montane forest
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Figure 4: Ecosystems types at the project site
7.8 4.3 Critical habitat assessment The results of the ADB critical habitat assessment matrix is provided in Table 12 which summaries the project area of influence cannot be considered as a critical habitat. None of plants and bird species of conservation concern listed as near threatened, vulnerable, endangered or critically endangered by the IUCN Red or the in the Samoa NBSAP were recorded during the plant and bird survey, or in previous surveys of any Samoan undertaken within the project area of influence. However, the reaches assessed as modified and natural habitat all provide critical habitat for migratory species. Additionally, the conditions of the flora and fauna as well as the significant level of human interventions over the past means that the presence for any of the biodiversity species of conservation concern as unlikely to survive or thrive in the present condition, and therefore will
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not be affected by the construction and the proposed long term use of the area for the multipurpose dam. Table 12: Critical Habitat Assessment Critical habitat criteria Present Reach Justification Habitat required for the No None No listed species have been recorded in the area survival of critically or the habitat considered as critical for endangered endangered or endangered species. species The habitat is not considered as critical to the survival of the critically endangered and endangered bird and plant species for Samoa. Areas having special Yes Upstream The endemic species manumea and maomao are significance for endemic or proposed present in the upper-catchment of Vaisigano restricted-range species dam Watershed but outside the Project area of influence. Sites that are critical for the Yes All Some of the sea birds are present within the site, survival of migratory species but their survival will not be critically affected by the project. These sea birds are found throughout the wider Apia Catchment KBA of which less than 2% will be affected by the PAI Areas supporting globally No None None of the IUCN Red List species of conservation significant concentrations or concern are present in the project area of numbers of individuals of influence. The area does not support any congregatory species significant concentrations of congregatory species Areas having biodiversity of Yes None The biodiversity within the project area of influence significant social, economic, does not hold any social, economic or cultural or cultural importance to significance to local communities or Samoan local communities culture. Areas either legally No None The project area of influence is within the wider protected or officially Apia Catchment KBA that is considered a site of proposed for protection national biodiversity conservation importance despite it being not legally protected. The wider Apia Catchment KBA includes the within it is the legally protected Mt Vaea Scenic Reserve and Lake Lanuto’o National Park. The sites have not been considered at the national level for any special global protection or recognition such as the Ramsar Site or World Heritage sites. The upper-catchment part of the Vaisigano Watershed Area which is outside the project area of influence is an important Habitat required for the survival of critically endangered or endangered species due to its classification as a Natural Habitat with undisturbed native forest and with the presence of the critically endangered manumea, and the endangered maomao.
4.4 Flora and Fauna Species of Conservation Concern:
Amongst the reasons for ADB requiring a full EIA for the proposed dam project is the literature which identified that the wider Apia Catchment KBA is home to some of the critically endangered and endangered bird species of Samoa.
7.8.1 4.4.1 Birds According to the SPS, due to their conservation significance, these bird species trigger one of the criteria for the definition of an area as critical habitat i.e. areas with high biodiversity value
34 Alaoa Multipurpose Dam - Terrestrial biodiversity and habitat assessment Revision No: 1 E307132 22 August 2019 including habitat required for the survival of critically endangered or endangered species. There are 11 bird species which are endemic to Samoa. Three of these are classified as endangered (EN) or critically endangered (CR) by the IUCN Red List. This are Maomao En (Mao) Gymnomyza samoensis), Manumea CR Tooth-billed Pigeon (Didunculus strigirostris) and Samoan moorhen CR (Punae). The Punae has not been seen in over 150 years so it is most likely extinct. The Maomao and Manumea are present around the country but in very low number according to assessment taken over the past 15 years in Samoa, by various organisations including MNRE, SPREP, Conservation International and Birdlife International.
The bird surveys found that the project area of influence although has high diversity and density of native birds’ presence, these birds are very common in modified habitat types and more importantly are not considered threatened or vulnerable. Most of these bird species do have a wide range of habitats that can survive both in mature forest and along the end of forests as well as open areas such as settlements. Additionally, the invasive bird species were very common around the PAI.
The birds of conservation concern such as the maomao, manumea was only found in the uppercatchment areas of the Apia Catchment KBA which are outside the project area of influence. The nature of the ecosystems in and around the project area of influence being that of mostly open and disturbed mixed vegetation, it is unlikely that the maomao and manumea would permanently inhabit these sites according to the ecology and habitats descriptions for the birds. Tooth-billed Pigeon (Didunculus strigirostris) Manumea (CR).
The Manumea is endemic to Samoa and is the only living species in the genus. This pigeon only lives within and on the edges of mature native forest in both Upolu and Savaii. Its numbers have declined dramatically, mostly through loss of habitat and hunting and it is classified as CR on the red List and is in significant danger of extinction 2
It is generally recognised from past information that the bird lives in primary forest from sealevel to 1,600 m, also occurring in forest edge, along forest roads and sometimes visiting clearings where native trees remain. It is specialised to feed on the seeds of Dysoxylum spp. The manumea is usually active when calling early morning, around mid-day and around dusk. IT is also generally acknowledged that it is very limited in its movement, thus when it is present in an area, one is likely to hear or see it when the area is visited over several days.
The Manumea siting or recording within the Apia Catchment have only been in higher altitudes and areas away from human influence. This is like other records is known to be found in the Central Savaii KBA, and mature forests such as in Uafato lowland forest, Matafaa and Tafua Peninsula.
Mao (Gymnomyza samoensis) Ma’oma’o (EN). The Ma’oma’o is endemic to the Samoan archipelago and is now believed to occur only in Samoa. It is a large, slim honeyeater with a long, down-curved bill and is described as having a remarkable voice. The Ma’oma’o is generally restricted to large areas of mature foothill and montane forest. It has A study by Butler and Sternimen noted that “The Ma’oma’o only occurs in areas with a canopy layer of trees. It does not occur in logged areas with no large tree canopy cover. But Ma’oma’o are present in modified habitat such
2 http://datazone.birdlife.org/species/factsheet/tooth-billed-pigeon-didunculus-strigirostris/text
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as areas with plantations where large trees still remain.” 3 It also been observed in an area of cinder cone, heathland scrub, at forest edge, in the wet forest at 760 m 4.
Insects are also an important part of the diet and are the main food source in the dry season although it has been observed feeding on a wide range of flowers trees including Erythrina spp, heliconia, ginger, banana and some orchids species. The Ma’oma’o is threatened by habitat loss and degradation and by invasive species such as rats and some hunting. This species is listed as Endangered on the IUCN Red List.5
8. 5. Potential Impacts The construction and operational of the dam will have potential short- and long-term impacts on the biodiversity of the area.
8.1 5.1 Short Term Impacts As noted in the survey results, most of the project area of influence which includes the inundated zone, the dam site, the construction site, and downstream are classified as modified habitat with vegetation, bird species and mammals present being typical of such habitats. With the absence of any biodiversity species of conservation significance the potential impacts include:
5.1.1 Flora:
Loss of vegetation at the construction site and the inundated zone. This loss of common and invasive species will not have significant impact on the surrounding vegetation. Nevertheless, land clearing is likely to cause soil erosion which in heavy rainfall periods can result in downstream impacts along the river and the coastal area.
5.1.2 Birds:
The land clearing, noise pollution and humans and construction activities are likely to cause impact on the birds found in the area which could result in some species being affected. With the site not having any birds which are confined only to the site, it is likely that most of the birds will migrate out of the area as construction begins. They will most likely move further upland in the natural habitat areas which will not disturbed or affected by the construction. Similarly, some birds that might be around after clearing will relocate once the inundated zone is flooded.
3 Butler, D. & Stirnemann, R, 2013, Leading the recovery of two of Samoa's most threatened bird species the tooth-billed pigeon (Manumea) and the mao (Ma'oma'o) through ecological research to identify current threats, Conservation International 4 http://datazone.birdlife.org/species/factsheet/mao-gymnomyza-samoensis/text 5 Butler, D. & Stirnemann, R, 2013, Leading the recovery of two of Samoa's most threatened bird species the tooth-billed pigeon (Manumea) and the mao (Ma'oma'o) through ecological research to identify current threats, Conservation International
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It is also likely that during construction some birds might hunted by workers, so it is vital that a strict ban in instituted and monitored as part of the construction to avoid workers from hunting the birds.
5.1.3 Mammals:
As the site was noted as not having any native fruit bat roosts, it is unlikely that they will establish a new roost during construction, therefore is not envisaged that the construction will have any impacts.
8.2 5.2 Possible Long-Term Impacts The reservoir will over time establish a new ecological dynamic in terms of biodiversity in the area and habitat. With appropriate mitigation measures such a replanting program for native trees, the area can have positive impacts on the recovery of native plants and birds in and around the project area of influence.
9. 6. Potential Mitigations: Recommendations 1. The Loss of vegetation within the project area of influence which includes the construction footprint, access ways, the dam and the reservoir could be offset through a native tree planting program and allowing for natural regeneration of the native forest around the inundated zone while clearing the area of invasive species. This would also be of benefit to bird and native invertebrate species.
2. Due the limited time available for the bird surveys, additional surveys prior to the start of the project as well as during the land clearing and construction period to map the bird population in the area is proposed.
3. IT is also recommended that during land clearing, an opportunity should be taken to undertake a full documentation of the epiphytes and ferns as well as possible plants along the ridge that were not accessible during the surveys recorded in this document.
4. A programme of education and awareness for site workers and a robust monitoring program should be put in place during the construction to prevent hunting of birds within and around the construction site.
5. These proposed mitigation measures will be included in the EIA prepared for the project and included in the EMP, that forms part of the EIA. The EMP will be included in the contract document for the project and the Construction Contractor must adhere to its findings when carrying out the Work. The Contractor will produce, within 30 days of Contract award a Sitespecific Environmental Management Plan (SEMP) taking on board the requirements of the EMP together with their own construction practices. The SEMP must be approved by the Client before any work commences at the site.
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10. 7. References • ABD: 2009: Safeguard Policy Statement • Asia Air Survey, 2014, National Forestry Inventory report for Samoa, MNRE and JICS • Atherton J. and Associates; 2013; Initial Environmental Examination: Samoa Alaoa HPP; Asia Development Bank • Atherton J. and Jefferies B. (editors) 2012: Guidelines for undertaking rapid Biodiversity assessments in terrestrial and Marine environments in the pacific. SPREP. Apia, Samoa. • Atherton, J and Tipamaa, T; 2009, Review of Status of Knowledge of Samoan Avifauna, • Atherton, J. 2004. Comparison of 1999 forest cover with previous forest covers maps. Extract from GIS Design and Development 3rd Mission Final Report for FAO, December, 2004, Apia, Samoa. • Atherton, J. 2008. Database on Birds of Samoa recordings • Beichle, U. 1991. Status and acoustical demarcation of pigeons of Western Samoa. Notornis 38(1): 81-86. • Beichle, U. 2006. Saving Samoa’s Critically Endangered Maomao and Manumea. Unpublished final report to Wildlife Conservation Society, June 2006, 20pp • Beichle, U. and Maelzer, M. (1985) A conservation programme for Western Samoa. Pp. 297–299 in Diamond, A. W. and Lovejoy, T. E., eds. Conservation of tropical forest birds. Cambridge, U.K.: International Council for Bird Preservation (Techn. Publ. 4). • Birdlife International. 2000. Threatened Birds of the World, Lynx Editions and Birdlife International, Barcelona, Spain & Cambridge, U.K. • Birdlife International. 2009 • Butler, D. & Stirnemann, R, 2013, Leading the recovery of two of Samoa's most threatened bird species the tooth-billed pigeon (Manumea) and the mao (Ma'oma'o) through ecological research to identify current threats, Conservation International • Butler, D. J. 2005. Restoration of Nu’utele & Nu’ulua, Aleipata Islands, Samoa. Protection of Friendly Ground Dove during Proposed Rat Eradication. Unpublished report for Govt of Samoa. Butler, D. J. 2006. Restoration of Nu’utele & Nu’ulua Islands, Aleipata Island Group, Samoa. Report of expedition to trial the capture and holding of friendly ground doves (Galicolumbia stairi). Unpublished report for Samoa Ministry of Natural Resources, Environment & Meteorology, Secretariat of the South Pacific Regional Environment Programme and Pacific Programme of the Cooperative Islands Initiative. • CI, MNRE AND SPREP. 2010. Priority Sites for Conservation in Samoa: Key Biodiversity Areas. Apia, Samoa. 32pp. • Clarkson, B.D., Dugdale, J.S., Whistler, W.A., Butler, D., Schuster, C., Robinson, T. 1995. Technical Report on the Pilot Study of the Upland Ecosystems of Western Samoa. Landcare Research, Wellington, New Zealand. • Collar N. J. (2015) Natural history and conservation biology of the tooth-billed pigeon (Didunculus strigirostris): a review Pacific Conservation Biology 21(3) 186-199 https://doi.org/10.1071/PC14923 • Conservation International – Pacific Islands Programme, Ministry of Natural Resources and Environment, Secretariat of the Pacific Regional Environment Programme. 2010 Priority Sites for Conservation in Samoa: Key Biodiversity Areas. Apia, Samoa. • Dhondt, A.1976. Bird Observations in Western Samoa. Notornis 23: 29-43.
• FAO. 2005.Strengthening the institutional capacity of the Samoa forestry division to effectively plan and manage forest resources. Final project report. Report written for the Government of Samoa by FAO. Apia, Samoa.
Terrestrial biodiversity and habitat assessment
• Government of Samoa. 2001. Samoa’s Biodiversity Strategy and Action Plan. Keep the Remainder of the Basket. Government of Samoa, Apia. • Holloway, C.W., Floyd, C.H. 1975. A National Parks System for Western Samoa. United Nations Development Advisory Team for the South Pacific. • https://en.wikipedia.org/wiki/Tooth-billed_pigeon • IUCN Red list. https://www.iucnredlist.org/search • Kear, D. and Wood, B.L. (1959). The Geology and Hydrology of Western Samoa. NZ Bulletin 63. Welling ton, Geological Survey. • Lovegrove, T., Bell, B. and Hay, R. 1992. The indigenous Wildlife of Western Samoa: The Impacts of Cyclone Val and a Recovery and Management Strategy. NZ Ministry of Conservation • Ministry of Mines, Energy and Rural Electrification; 2017; Environmental and Social Impact Assessment; Tina River Hydropower Development Project (TRHDP Solomon Islands Government • MNRE, 1996. Post Cyclone Bird Monitoring Program, unpublished • MNRE, 2006a. Recovery Plan for the Manumea or Tooth-biled Pigeon (Didunculus strigirostris). Ministry of Natural Resources and Environment, Government of Samoan, Apia, Samoa. • MNRE, 2006b. Recovery Plan for the Ma’oma’o or Mao (Gymnomyza samoensis). Ministry of Natural Resources and Environment, Government of Samoan, Apia, Samoa. • MNRE, 2015; Samoa National Biodiversity Strategy and Action Plan • MNRE. 2006. Recovery Plan for the Manumea or Tooth-billed Pigeon (Didunculus strigirostris). Ministry of Natural Resources & Environment, Samoa. • Ollier, C., W.A. Whistler, and A.B. Amerson Jr. 1979. O le Pupu-Pu‘e National Park, Western Samoa. UNDAT, Suva, Fiji. 2 vols. • Park, G., Hay. J., Whistler, W.A., Lovegrove, T and Ryan, P. 1992. The National ecological Survey of Western Samoa: the conservation of biological diversity in the coastal lowland of Western Samoa. New Zealand Department of Conservation. • Parrish, R., Stringer, I and Lester, P. 2004. Fauna survey of the Aleipata Islands, Samoa. 3rd Progress Report. Institute of Applied Sciences Technical Report No. 2004/05. Institute of Applied Sciences, the University of the South Pacific, Fiji. • Patrick, Brian … [et al.] 2014, Guidelines for undertaking rapid biodiversity assessments in terrestrial and marine environments in the Pacific Apia, Samoa: SPREP, Wildlands • Pearsall, S. H. and Whistler, W. A. 1991. Terrestrial ecosystem mapping for Western Samoa. Report to the Government of Samoa by South Pacific Regional Environment Programme and East-west center, Environment and Policy Institute, Honolulu, US. 72pp • Pearsall, S.H. and W.A. Whistler. 1991A. Terrestrial ecosystem mapping for Western Samoa: summary, project report, and proposed National Parks and Reserves Plan. South Pacific Regional Environmental Programme, Noumea. 72 pp.
• Pearsall, S.H. and W.A. Whistler. 1991B. Ecosystem mapping for Western Samoa: technical report and appendices. South Pacific Regional Environmental Programme, Noumea. 213 pp. Schuster, C, et al; 1997, Conservation of Biological Diversity in Upland Ecosystems of Samoa, NZMFAT • Schuster, C. 2009. Bird counts of Nuutele Island (unpublished accounts) • Schuster, C. 2010; Samoa Important Bird Areas; Birdlife International • Schuster, C., Whistler, W.A. and Tuiailemafua, S. 1997. The Conservation of Biological Diversity in Upland Ecosystems of Samoa, New Zealand Ministry of Foreign Affairs and Trade. • Solomon Islands Government, 2017, Environmental Impact Assessment Tina River Hydropower Development Project (TRHDP), Asian Development Bank • Stirnemann, R. L. Potter, M., Butler, D., and Minot, E., (2016 a) The breeding biology of the Mao an endangered large tropical forest passerine, Bird Conservation International: 1-14
• Stringer, I., Parrish, R. and Sherley, G. 2003. Report on the first monitoring visit to Nu’utele and Nu’ulua Islands 25 – 31 July 2000. Institute of Applied Sciences Technical Report No. IAS 2003/10. Institute of Applied Sciences, the University of the South Pacific. • Tarburton, M. K. 2001. Observations on the status of the land birds, wading birds and seabirds of Samoa. Emu 101:349 – 360. • Taulealo, T. I. 1993. Western Samoa State of the Environment Report. SPREP, Apia; Samoa • Tipama’a, T. and Beichle U., 2006. RNHP Manumea Maomao Bird Survey Data, in draft, (personal communications) • Tipama’a, T., 2001. Preliminary Status Report on Bird Counts on Selected Monitoring Sites on Upolu & Savaii, Unpublished final report. June 2001. 7pp • Whistler, W.A. 2001. Plants in Samoan culture: the ethnobotany of Samoa. Isle Botanica, Honolulu. 234 pp. • Whistler, W.A. 2002. The Samoan rainforest: a guide to the vegetation of the Samoan Archipelago. Isle Botanica, Honolulu. 169 pp.