IFE AND WlLDLl ITAT OF AMERICAN SA VIRONMENT AND ECOLO By A. Binion Amerson, Jr., W. Arthur Whistler, and Terry D. Schwaner Environment Consultants, Inc., Dallas, Texas Edited by Richard C. Banks U.S. Fish and Wildlife Service Washington, D.C. UNITED STATES DEPARTMENT OF T E INTERIOR FISH AND WILDLIFE SERVICE Washington, D.C. e 1982 Foreword A survey of the status of the wildlife and wildlife habitat of American Samoa. an unincorporated Territory of the United States. was recommended by administrative officials of the U.S. Fish and Wildlife Service (FWS) in the early 1970s .Environ- ment Consultants. Inc . (ECI). based in Dallas. Texas. was selected to conduct a 2-year survey with A .Binion Amerson. Jr., as Principal Investigator . The contract was administered through the Division of Federal Aid in FWS Region I. Portland. Oregon . The primary objectives of the survey were (1) to define the major ecosystems and to inventory their physical components. vegetation. and wildlife constituents; (2) to prepare maps of these ecosystems; (3) to identify any threatened or endangered species of wildlife; and (4) to recommend wildlife management opportunities and needs . The report of the survey was to be in two parts . The first was to be a non-technical account suitable for wide general distribution; the second was to include the technical aspects of the data and data gathering. with accounts of the wildlife species . This volume represents the first part of ECI's report . The final report submitted by ECI contained more than 1. 200 pages. 200 figures. and 110 tables. many of thelatter several pages long . The FWS felt that the report was too lengthy for publication in the form submitted . The task of editing and con- densing ECI's report into publishable form. without altering its essentials. was assigned to Richard C . Banks. National Fish and Wildlife Laboratory. FWS. Washington. D.C. Claudia J . Angle assisted with revision of the figures. and Linda Wolfe retyped most of the text . Contents Page Foreword ......................................................................ii Abstract .......................................................................1 Introduction ...................................................................2 History of the Project ......................................................... 2 Objectives of the Study ........................................................ 3 Samoan Scientific History .....................................................3 7 .- Procedures ....................................................................6 Physical Environment ........................................................... 8 Geography .................................................................. 8 Geology ..................................................................... 8 Soils .........................................................................12 Climate ..................................................................... 14 LandUse ....................................................................14 Biological Environment .........................................................19 Plants .......................................................................19 Amphibians and Reptiles ......................................................45 Birds .......................................................................49 Mammals ...................................................................56 Community Relationships .......................................................58 Diversity of Ecosystems .........................,, ............................58 Variation in Plant Communities .................................................58 Habitat Preferences ...........................................................62 Findings and Recommendations Regarding Resource Management ..................... 62 Potentially Threatened or Endangered Species ....................................63 Potentially Threatened Habitats ................................................65 Areas Important to Wildlife Protection ..........................................68 Conservation and Management Programs ........................................71 Suggested Future Research .....................................................73 Acknowledgments ..............................................................74 References .....................................................................75 Tables ........................................................................78 Wildlife and Wildlife Habitat of American Samoa. I. Environment and Ecology A. Binion Amerson, Jr., W. Arthur Whistler, and Terry D. Schwaner Environment Consultants, Inc. Dallas, Texas Abstract A survey of the status of the terrestrial vertebrate wildlife and the wildlife habitat of American Samoa was conducted from 15 June 1975 to 21 December 1976. Data were collected from42 study plots in 16 vegetation communities and habitat types on the seven islands, and from 98 linear survey routes between the study plots. American Samoa consists of five volcanic islands and two atolls in the Tropical climatic zone. The vol- canic istands were originally covered with Tropical Rain Forest, much of which is now highly disturbed. There is a small cloud forest zone. Plantation land, rain and ridge forests, secondary forest, and village land now make up most of the habitats. One species of amphibian and 15 of reptiles occur in American Samoa. The avifauna includes 54 species. There are seven species of mammals. Undisturbed habitats are most used by the native wildlife, whereas introduced species are most abundant in disturbed areas. Threatened and endangered wildlife species and habitats are identified, and possible programs for their protection are discussed. Introduction History of the Project American Samoa, in the Southwest Pacific (Fig. I), is an In December 1973 the U.S. Fish and Wildlife Service unincorporated Territory of the United States administered (FWS) issued a request for proposals for a survey of the wild- by the U.S. Department of the Interior. Although American life and wildlife habitat of the islands of American Samoa. Samoa has not been subjected to apparent, extensive wildlife Environment Consultants, Inc. (ECI) was selected as the habitat degradation, population growth from 5,000 in 1900 contractor. The project officially began on 20 March 1975. to 29,190 in 1975 has precipitated development pressures During the first 3 months of the project, spent in preparation which could lead to adverse environmental impacts. Knowl- for the intensive field survey, all pertinent literature was edge of local biotic systems is therefore necessary so that assembled and reviewed. The resultant bibliography of Sa- planners can protect and enhance the valuable natural en- moan wildlife and wildlife habitat incorporated more than vironment of these islands. 200 entries; an additional bibliography of about 400 articles In the early 1970s, administrative officials suggested that a relevant to Southwest Pacific island ecology was also com- thorough field inventory and assessment of the plant and piled. wildlife constituents of the seven islands of American Samoa In June 1975, ECI established an office in Pago Pago, on (Fig. 2) was necessary. Such a survey would serve as a thresh- Tutuila Island. The first several weeks in Samoa were used old for investigations on specific wildlife conservation prob- for reconnaissance of the islands and selection of community lems, provide facts needed by adminstrators in making type study plots. The quantitative inventory of wildlife and judgments on conservation issues, and identify threatened or wildlife habitats was begun on 15 June 1975 and continued endangered species living on the islands. for 18 months, through 21 December 1976. HAWAIIAN IS. ,' &, -''4 ,,, ;'-($:!$AMERICAN SAMOA 805-2--2285 -TAHITI , (q:I 'TONGA IS. "4$1 I Fig. 1. General location of the islands of American Samoa. Distances to other location:, are shown in km. PACIFIC OCEAN WEST OLU IS. 14O l°Fu IS. .* OLOSEGA IS. 1 ROSE ATOLL . Fig. 2. Regional setting of the islands of American Samoa and their relationship to Western Samoa. Objectives of the Study 2. Prepare maps of American Samoa showing the distri- bution of the ecological types. Because relatively little quantitative data regarding wild- 3. Describe the roles of disturbance and succession as life and wildlife habitat of American Samoa existed at the in- determinants of the existing plant and animal com- ception of this project, it was necessary to establish objec- munities. tives which would maximize collection of the most important 4. Identify and record the status of any species (plant or information within the time and funding limitations of this animal) threatened with extinction or extirpation, and project. The primary objectives were to: to describe the factor(s) responsible. 1. Define the major ecological types (plant communities) 5. Identify management opportunities and options for the which collectively make up American Samoa by: wild!ife and wildlife habitat of American Samoa, and a. describing each community generally in terms of describe future research needs. soils, moisture, light, slope, elevation, and other A secondary objective of the study was to determine the ef- physical factors; fects of Polynesian rat predation on birds and turtles at Rose b. identifying the plant species, with special emphasis Atoll National Wildlife Refuge. on the vascular flora, which characterize each com-