COOPERATIVE NATIONAL PARK RESOURCES STUDIES UNIT UNIVERSITY OF HAWAI'I AT MANOA Department of Botany 31 90 Maile Way Honolulu, Hawai'i 96822 (808) 956-82 18 Clifford W. Smith, Unit Director Technical Report 124 VEGETATION ABOVE A FERAL PIG BARRIER FENCE IN RAIN FORESTS OF KILAUEA'S EAST RIFT, HAWAII VOLCANOES NATIONAL PARK Linda W. Pratt, Lyman L. Abbott, and David K. Palumbo USGS Biological Resources Division Pacific Island Ecosystems Research Center Kilauea Field Station P. 0. Box 52 Hawaii National Park, HI 96718 University of Hawai'i at Manoa National Park Service Cooperative Agreement 801 0-2-9004 December 1999 TABLE OF CONTENTS Page ... LIST OF FIGURES ................................................ 111 LIST OF TABLES .................................................vi SUMMARY ...................................................... 1 ACKNOWLEDGMENTS ........................................ 2 INTRODUCTION ................................................. 3 THE STUDY AREA ................................................ 4 Geology and Soils ........................................... 4 Climate .................................................... 5 Vegetation ................................................. 5 PastLandUse .............................................. 6 METHODS ......................................................6 Sampling Scheme and Data Collection ........................... 6 Alien Plants ............................................ 7 Rare Plants ........................................... 7 Clermontia Frequency and Density ......................... 7 Density of Tree Ferns ................................... 7 'Olapa (Cheirodendron trigynum) Density .................... 8 Vegetation in Pig-Disturbed Plots .......................... 8 Soil Depth ............................................ 8 Pig Activity ............................................ 8 RESULTS ....................................................... 9 Alien Plant Species Distribution and Abundance .................... 9 Broomsedge (Andropogon virginicus) ....................... 9 Meadow Ricegrass (Ehrharta stipoides) .....................9 Hilo Grass (Paspalum conjugatum) ......................... 9 Firetree (Myrica faya) ................................... 9 Strawberry Guava or Waiawi (Psidium cattleianum) ........... 10 Yellow Himalayan Raspberry (Rubus ellipticus) .............. 10 Cane Tibouchina (Tibouchina herbacea) ................... 10 Scaly Swordfern (Nephrolepis multiflora) ................... 10 Other Alien Plants ..................................... 11 Changes in Frequency of Alien Plants over Five Years ........ 11 Rare Plant Species ......................................... 15 Jewel Orchid (Anoectochilus sandvicensis) and 'awapu hi a Kanaloa (Liparis hawaiensis) ....................... 15 Hame (Antidesma platyphyllum) .......................... 15 Lobelioids: 'Oha Kepau (Clermontia hawaiiensis). 'Oha (C. pan~iflora). Cyanea degeneriana. and Koli' i ( Trematolobelia grandifolia) ........................ 15 TABLE OF CONTENTS (Continued) Page RESULTS (Continued) Rare Plant Species (Continued) Hahala (Cyrtandra paludosa). 'Ilihia (C. platyphylla). and other Cyrtandra ....................................... 17 Kamakahala (Labordia hedyosmifolia) ..................... 18 Opuhe (Urera glabra) and 'Ohe (Tetraplasandra hawaiiensis) ... 18 'Iliahi or Sandalwood (Santalum paniculatum) and Neneleau (Rhus sandwicensis) ............................. 18 Rare Plant Species not Found in 1992-94 .................. 19 Clermontia Frequency and Density ............................. 20 Density of Tree Ferns (Cibotium spp.) .........................21 Density and Population Structure of 'Olapa (Cheirodendron trigynum) . 22 Vegetation in Pig-Disturbed Plots ...............................26 Groundcover ........................................26 Woody Plant Density ................................... 29 TreeFerns ........................................... 32 SoilDepth ................................................34 Feral Pig Activity ........................................... 35 DISCUSSION ................................................... 38 Alienplants ............................................... 39 Grasses .............................................39 Treesandshrubs ..................................... 40 Scaly Swordfern ...................................... 42 Rare Plant Species and Clermontia Frequency .................... 42 Density of Tree Ferns ........................................44 ~ensityof 'Olapa ...........................................45 Vegetation in Pig-Disturbed Plots ..............................46 Feral Pig Activity ........................................... 47 MANAGEMENT CONSIDERATIONS ................................. 48 LITERATURE CITED ............................................. 50 LIST OF FIGURES Page 1. The East Rift study area in Hawaii Volcanoes National Park, island of Hawai'i, showing the barrier fence, trails, transects, and historic lava flows ..... 60 2. Distribution and estimated abundance of broomsedge (Andropogon virginicus) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. ............................................. 61 3. Frequency of occurrence of eight alien plant species in five categories of cover-abundnce along transects in East Rift forests, Hawaii Volcanoes National Park. ............................................. 62 4. Frequency of occurrence of eight alien plant species in five categories ,of cover-abundnce along four transects in forests of Kahauale'a. ........ 63 5. Distribution and estimated abundance of Hilo grass (Paspalum conjugatum) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. ............................................. 64 6. Distribution and estimated abundance of firetree (Myrica faya) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. 65 7. Distribution and estimated abundance of strawberry guava (Psidium cattleianum) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. ..................................... 66 8. Distribution and estimated abundance of yellow Himalayan raspberry (Rubus ellipticus) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. .............................................67 9. Distribution and estimated abundance of cane tibouchina (Tibouchina herbacea) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. ..................................... 68 10. Distribution and estimated abundance of scaly swordfern (Nephrolepis multiflora) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. ............................................. 69 11. Distribution of jewel orchid (Anoectochilus sandvicensis) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park.. ..... 70 LIST OF FIGURES (Continued) Page Distribution of hame (Antidesma platyphyllum) in East Rift forests above and just below a feral pig barrier fence, Hawaii Volcanoes National Park.. .. 71 Distribution of 'dha kepau (Clermontia hawaiiensis) and koli' i (Trematolobelia grandifolia) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. .....................................72 Distribution of 'dha (Clermontia pan~iflora)in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. .................... 73 Distribution of hahala (Cyrfandra paludosa) and Cyrtandra spp. in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park., 74 Distribution of 'ilihia (Cyrfandra platyphylla) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. ................. 75 Distribution of kamakahala (Labordia hedyosmifolia), dpuhe (Urera glabra), and 'ohe (Tetraplasandra hawaiensis) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. .................... 76 Distribution of 'iliahi (Santalum paniculatum) and neneleau (Rhus sandwicensis) in East Rift forests above a feral pig barrier fence, Hawaii Volcanoes National Park. ..................................... 77 Frequency of 'dha (Clermontia spp.) in five height classes and three rooting categories along all primary transects in East Rift forests, Hawaii Volcanoes Naitonal Park (transectsl ,1A,2,2A,2Cl 3, and 3A) .................. 78 Frequency and density of 'dha (Clermontia spp.) in five height classes and three rooting categories along Kahauale'a transects and an equal length of transects (3 and 3A) in forests of Hawaii Volcanoes National Park ..... 79 Frequency and density of '6ha (Clermontia spp.) in 1993 and 1994 along three re-monitored transects within forests of the East Rift, Hawaii Volcanoes National Park ..............................................80 Density (mean no./1002) of tree ferns (Cibotium spp.) in five trunk height classes along transects in East Rift forests of Hawaii Volcanoes National Park .............................................. 81 LIST OF FIGURES (Continued) Page Density (mean no./1002) of tree ferns (Cibotium spp.) in three trunk height classes along the upper and lower halves of three transects in East Rift forests of Hawaii Volcanoes National Park ............................. 81 Size class distribution of 'blapa (Cheirodendron trigynum) in 80 plots along transects in East Rift forests of Hawaii Volcanoes National Park