COOPERATIVE NATIONAL PARK RESOURCES STUDIES UNIT UNIVERSITY OF HAWAII AT MANOA Department of Botany 3190 Maile Way Honolulu, Hawaii 96822 (808) 956-8218 Technical Report 87 BOTANICAL INVENTORY OF THE PROPOSED TUTUILA AND OFU UNITS OF THE NATIONAL PARK OF AMERICAN SAMOA Dr. W. Arthur Whistler Department of Botany University of Hawai'i at Manoa, Honolulu, HI 96822 Cooperative Agreement CA 8034-2-0001 April 1994 COMl INWEALTH OF ' THE 3RTHERN ... MARL A ISLANDS a GUAM ISLANDS OF SAMOA 0 50 100 L I rE MILES C: " .. REPUBLIC +. OF PALAl FEDERATED ;TATES. OF MIC 'UPOLU . Western I OLOSEGA Samoa ROSE 0 American Samoa ATOLL ISLANDS SOCIETY NIUE ' 1;. ,. ISLANiS . PA---- Tropic of AUSTRALIA Figure 1 Location Map motional I ' Line I THE PACIFIC OCEAN TABLE OF CONTENTS I . INTRODUCTION ..................................................................................................................................1 The Geography ..................................................................................................................................1 ..I hc Climate ........................... .. .....................................................................................................I The Geology ......................................................................................................................................1 Floristic Studies on Tutuila ...............................................................................................................4 Vegetation Studies on Tutuila ...........................................................................................................8 11. METHODOLOGY ....................... ................................................................................................. 9 I11. VEGETATION OF THE PARK ...........................................................................................................10 Primary Vegetation ....................................................................................................................... 10 A . Littoral Vegetation .................................................................................................................10 1 . Herbaceous Strand ................................... .... .....................................................................11 2 . Littoral Shrubland ......................................................................................................... 16 3 . Littoral Forest ..................................................................................................................16 B . Wetlands ................................................................................................................................18 4 . Coastal Marsh ...................................................................................................................20 C . Rainforest ........................... .................................................................................................20 Variation within the Rainforest .............................................................................................20 Characteristics of Rainforest .................................................................................................22 5 . Lowland Forest .................................................................................................................23 a . Valley Lowland Forest ....................... ... ..............................................................23 b . Coastal Lowland Forest ..............................................................................................26 c . Ridge Lowland Forest .................................................................................................27 6 . Montane Forest ...............................................................................................................30 D . Summit Vegetation ................................................................................................................34 7 . Montane Scrub ................................................................................................................34 Secondary Vegetation ......................................................................................................................36 8 . Managed Land Vegetation ..............................................................................................36 9 . Secondary Scrub ..................... ....................................................................................38 10. Secondary Forest ...........................................................................................................39 IV . DISCUSSION AND RECOMMENDATIONS ....................................................................................40 V . ACKNOWLEDGEMENTS .................... ... .....................................................................................42 V1 . LITERATURE CITED ........................... .. ........................................................................................43 APPENDIX A: ANNOTATED CHECKLIST OF THE FLORA OF TUTUILA .............................................. 45 APPENDIX B: PLOT DATA ...........................................................................................................................108 APPENDIX C: SEASONALITLY OF IMPORTANT FRUIT-BEARING TREES AND SHRUBS IN THE PARK AREA ...................................................................................................................... 120 APPENDIX D: THE OFU UNIT OF THE NATIONAL PARK OF AMERICAN SAMOA ............................125 APPENDIX E: PLANTS AS INDICATORS OF PAST LAND USE ..............................................................129 APPENDIX F: SUMMARY OF THE VASCULAR FLORA OF THE TUTUILA UNIT OF THE NATIONAL PARK OF AMERICAN SAMOA ................................................................... 132 LIST OF FIGURES 1 . Map of the Pacific showing the location of Samoa ........................................................... Frontispiece 2 . Map of Samoa ......................................................................................................................................2 3 . Vegetation map of the Tutuila park ......................................................................................................3 4 . Pago Pago Bay, with Mt . Matafao in the distance ..................................................................................5 5 . Mt . Pioa, a trachyte plug .........................................................................................................................5 6 . I'olauta Ridge and Pola Islet, Vatia .........................................................................................................6 7 . Amalau Valley .................................................................................................................................. 6 8 . Amalau beach ......................................................................................................................................12 9 . Coral rubble beach north of Vatia; Pola Islet in the distance .................................................................12 10. Tuafanua Beach west of Vatia ...............................................................................................................13 1 1 . Tafeu Cove west of Vatia ........................... .. ....................................................................................13 12 . I, &oral shrubland vegetation on windswept Sauma Point ....................................................................15 13. Littoral shrubland vegetation on Polauta Ridge ................................................................................... 15 14. Littoral shrubland vegetation on Pola Islet ..........................................................................................17 15 . Aiga Bay, west of and outside of the Tutuila park ............................................................................... 17 16. Littoral forest north of Vatia ................................................................................................................19 17. Vatia coastal marsh ................................................................................................................................19 18. Streamside vegetation at Amalau Valley ........................................................................................... 24 19. Coastal lowland forest near Tafeu Cove .............................................................................................. 26 20 . Disturbed lowland forest on ridges north of Mt . Alava ..................................................................... 26 21 . Ridge lowland forest west of Amalau Valley ........................................................................................29 22 . Montane forest on Alava Ridge ......................................................................................................... 29 23 . Montane forest on Toa Ridge ........................................................................................................... 31 24 . Lomagramma cordipinna dominating floor of montane forest ........................................................ 33 25 . Mauga-0-Tula Ridge behind Vatia .................................................................................................... 35 26 . Montane scrub vegetation on Mauga-o-Tula, Vatia ............................................................................35