Hawaii Volcanoes National Park · Volcanoes Hawaii Volcanoes National Park Rhonda Loh and Tim...

Special Ecological Areas …

20 years of Alien Plant

Management at Hawai‘i

Volcanoes

Hawaii Volcanoes National Park

Rhonda Loh and Tim Tunison

Hawaii Volcanoes National Park

Kahuku(116,000 ac)

Park Ecosystems…Coastal Strand

Lama Forest

Dry ‘Ōhi‘a Scrubland

Park’s Ecosystems…Pioneer communities

…Montane Shrubland

…Rain Forest

Photos © Thomas Belfield

Rare species,,,

The park provides habitat for over 50 federally listed threatened, endangered and candidate endangered species

‘Akepa

Hau kuahiwi

Nēnē

Mauna LoaSilversword

History of Natural Resources Management…

Feral Ungulates in the Park

Feral Ungulate Management in Hawai‘i Volcanoes NP, 2007

Fence – 110 miles

Managed for all ungulates (~45,000 ac)

Managed for goats, cattle mouflon (133,000 ac)

Park boundary

Kahuku(116,000 ac)

Kīlauea

Mauna LoaStrip

‘Ōla‘a Tract

Koa Forest Recovery on Mauna Loa Strip, 2003

Boundary Fence

Boundary Fence

19781975

Vegetation recovery following fencing and animal removalin rain forest (Katahira 1980)

Alien Plants at HAVO

Kahili ginger replaces native understory and prevents native trees from establishing

Strawberry Guava (Psidium cattleianum) along Highway 11, Hawai‘i Island

Faya tree increases Nitrogen inputs on young volcanic soils

Alien Grasses increase fire size and frequency

Total Acres Burned (ac)

0

4000

8000

12000

16000

1922-1931 1932-1941 1942-1951 1952-1961 1962-1971 1972-1981 1982-1991 1992-2001 2002-2004

Alien Plant Management Strategies (NPS 1986)

# of plantsor

area of infestation

Time

Eradication(Maximumcost-benefit)

Exclusion(exclude from valued areas)

No control(rehabilitation/

alternative restoration

Containment(prevent spread)

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Fountain Grass Distribution at Hawai‘i Volcanoes

30 kilometers

Small Populations (treatment area = 178.4 ac)

Core Populations (treatment area = 1000.4 ac)

Helicopter/vehicle/foot survey & control (106,210 ac)

N

PACIFIC OCEAN

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Kilauea

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Fountain Grass Control in Hawai’i Volcanoes National Park

Number of individuals removed

Parkwide controlControl of satellite populations

1996-20051993-1995

02000400060008000

1000012000

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

Fiscal Year

Indi

vidua

ls

Satellite Populations

Parkwide Control

Range Reduction

- Representativeness and/or rarity of vegetation

- Manageability/Vegetation Intactness

- Research and interpretive values

- Plant species diversity/richness/presence of rare species

- Incremental approach. Can be expanded & new ones added as resources become available

SPECIAL ECOLOGICAL AREA’S (SEA)REMOVE DISRUPTIVE WEEDS FROM HIGH PRIORITY AREAS

Systematic ground and/or aerial sweeps

Treatment of all target species within the area(11 spp in 1984)

Revisit sites at 1-4 year intervals

Special Ecological Areas 1985-2007

10 miles

Fences

1985-19891990-20002001-present

How effective is removing target weeds from SEA’s?

What is the cost of managing weeds over time ?

Seasonal Dry ‘Ōhi‘a Woodlands

SEA’s

(18,058* ac)

*includes 10,488 ac helicopter swept

0

0.5

1

1.5

0 5 10 15 20 25

Puaulu Buffer Ainahou Hilina Pali Kahalii Keam oku

01020304050

0 5 10 15 20 25

Puaulu Buffer Ainahou Hilina Pali Kahalii Keam oku

Treated Individuals/AcreIn

divi

dual

s/A

cre

Years Following Initial Treatment

Wor

ker D

aysA

cre

Worker Days/Acre

<0.2 worker day/acre or$40/acre every 2-4 yrs

1-10 individuals/ac

Keamoku Block A&B (2975ac)Worker Days/Acre

0

50

100

150

200

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

Year

Worke

r Day

s/Acre

Increased use of Helicopter search and aerial treatment reduces workloads

~$1/acevery 2-4 years

Keamoku SEA

Worker Days/Acre

Rain Forest Units 2,491 ac

0

200

400

600

800

0 2 4 6 8 10 12 14 16 18

Treated Individuals/Acre

Thurston (n=13) Small Tract (n=5) Koa Unit (n=7)In

divi

dual

s/A

cre

Years Following Initial Treatment

012345

0 2 4 6 8 10 12 14 16 18Wor

ker D

aysA

cre Worker Days/Acre

$156/ac every 2-4 yrs

~100 individuals/acre

$760/ac every 2 yrs

~600 individuals/acre

Monitoring transects?

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Distribution of Himalayan raspberry in `Ola`a Rainforest SEA

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<1%1-5%5-25%

% Cover

500 m

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Distribution of Kahili Ginger

<1%1-5%5-25%

% Cover

500 m

#

#

#

Mesic Forest Units - 458 ac

0

10

20

30

40

50

1985 1990 1997Year

Freq

uenc

y

Kahili ginger Nasturtium Strawberry guava Jerusalum cherry

Number of weeds along transects in Kipuka Puaulu SEA

0500

100015002000

020000400006000080000

Acr

es

Worker Days

Acres Under ManagementGround Partial Ground + Helicopter

Fiscal Year

Wor

ker D

ays

Special Ecological Areas 1985-2007

12,578 ac

66,039 ac

730 1,149

1985 20051990 1995 2000

1985 20051990 1995 2000

0.00

0.02

0.04

0.06$11.62/ac $3.40/ac

Wor

ker D

ay/A

c

Worker Day $ Cost/Acre

Fiscal Year

Special Ecological Areas 1985-2007

Ground + Helicopter Sweeps

1985 20051990 1995 2000

0

5000

10000

15000

0.0

0.1

0.2

0.3$58/ac $22/ac

Worker Days $ Cost/Acre

Acres

Acr

es

Wor

ker D

ay/A

cGround Swept SEAS 1985-2007

Fiscal Year

2,089 ac

10,535 ac

1985 20051990 1995 2000

Conclusions:

1) Populations of alien plant species can be reduced and maintained at very low levels after several cycles of control work

2) Subsequent recruitment of alien plants from the soil seed bank and seed rain from nearby areas

4) Workloads drop significantly after initial control efforts

3) Continued follow-up treatments are required in all areas and may be needed indefinitely

Future Directions Addition and Expansion of new SEAs

Optimize treatment intervals

Improve technologies – imagery and analysis, control methods, biocontrol

Increase community participation

Reduce seed rain/recruitment- expand units and establish buffer areas

Reclaim/restore adjacent degraded areas

Partnerships with adjacent landowners

Acknowledgements- Chris Zimmer, Mike Gates, Julie Leialoha, Alison Ainsworth, Bobby Mattos, Jon Makaike, David Benitez, Linda Pratt, Chuck Stone, Resources Management Staff, Pacific Island Exotic Plant Management Team, Cooperative Ecosystem Studies Unit- Research Corporation of University of Hawai‘i, Big Island Invasive Species Committee, Three Mountain Alliance, Hawai‘i Forest and Trails, Friends of Hawai‘i Volcanoes, Forest TEAM Program, Youth Conservation Corp, Alu Like.

MAHALO!