LAYSAN ISLAND ECOSYSTEM RESTORATION PLAN by Marie Morin1 and Sheila Conant2 University of Hawaii at Manoa Dept. of Zoology Honolulu, Hawaii 96822 1 (808) 326-9390, [email protected] 2 (808) 956-8241, [email protected] August 1998 i TABLE OF CONTENTS EXECUTIVE SUMMARY ...................................................................................................................................................VII RATIONALE ...........................................................................................................................................................................VII LAYSAN TERRESTRIAL BIOTA ...............................................................................................................................................VII RESTORATION OBJECTIVES....................................................................................................................................................VII TABLE 1. LIST OF RECOMMENDED PROJECTS......................................................................................................viii LIST OF TABLES.................................................................................................................................................................. IX LIST OF APPENDICES........................................................................................................................................................ IX LIST OF ATTACHMENTS .................................................................................................................................................. IX LIST OF FIGURES................................................................................................................................................................ IX INTRODUCTION .....................................................................................................................................................................1 BACKGROUND .........................................................................................................................................................................1 LAYSAN ISLAND: LEGAL MANDATES AND MISSION ................................................................................................................1 GENERAL "PRISTINE" DESCRIPTION (HISTORICAL) .................................................................................................................2 VEGETATION ASSOCIATIONS ...................................................................................................................................................2 THE FAMOUS DEVASTATION ...................................................................................................................................................3 PLANTS .....................................................................................................................................................................................4 NATIVE PLANT REINTRODUCTION ...........................................................................................................................................4 TABLE 2. LIST OF PLANTS FOR REINTRODUCTION, INTRODUCTION, OR ENHANCEMENT..............................5 NONNATIVE PLANT CONTROL AND ERADICATION ..................................................................................................................6 TABLE 3. ORIGINAL 1896 INDIGENOUS AND ENDEMIC LAYSAN FLORA BASED ON SCHAUINSLAND DESCRIPTION (1899).......................................................................................................................................................7 TABLE 4. PLANTS INTRODUCED TO LAYSAN THAT BECAME ESTABLISHED AND ARE STILL PRESENT..........9 TABLE 5. NON-NATIVE PLANTS INTRODUCED TO LAYSAN THAT ARE NO LONGER PRESENT .......................10 SPECIES WHICH COULD BECOME INTRODUCED "NATURALLY".............................................................................................10 NATIVE PLANT RECOMMENDATIONS.....................................................................................................................................11 Cenchrus agrimonioides var. laysanensis........................................................................................................................12 Eragrostis variabilis ........................................................................................................................................................12 Lepturus repens................................................................................................................................................................13 Sporobolus virginicus ......................................................................................................................................................13 Cyperus laevigatus...........................................................................................................................................................14 Mariscus pennatiformis subsp. bryanii ............................................................................................................................15 Pritchardia sp. .................................................................................................................................................................15 Santalum ellipticum..........................................................................................................................................................16 Chenopodium oahuense ...................................................................................................................................................17 Achyranthes atollensis .....................................................................................................................................................18 Boerhavia repens .............................................................................................................................................................18 Sesuvium portulacastrum.................................................................................................................................................19 Portulaca lutea.................................................................................................................................................................19 Lepidium bidentatum var. o-waihiense ............................................................................................................................20 Capparis sandwichiana....................................................................................................................................................20 Tribulus cistoides .............................................................................................................................................................21 Ipomoea indica.................................................................................................................................................................22 Ipomoea pes-caprae.........................................................................................................................................................22 Nama sandwicensis..........................................................................................................................................................22 Heliotropium curassavicum .............................................................................................................................................23 Phyllostegia variabilis .....................................................................................................................................................23 Solanum nelsonii..............................................................................................................................................................23 ii Sicyos maximowiczii ........................................................................................................................................................24 Sicyos pachycarpus..........................................................................................................................................................24 Sicyos semitonsus.............................................................................................................................................................24 Scaevola sericea...............................................................................................................................................................25 Lipochaeta integrifolia.....................................................................................................................................................26 TABLE 6. PRIORITIZATION OF NATIVE PLANT REINTRODUCTION, INTRODUCTION, AND ENHANCEMENT ACTIVITY.........................................................................................................................................................................26 NONNATIVE PLANT RECOMMENDATIONS..............................................................................................................................27 Cynodon dactylon ............................................................................................................................................................28 Nicotiana tabacum ...........................................................................................................................................................28