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Susan Cordell, Ph.D. Research Ecologist Institute of Pacific Islands Forestry, PSW with assistance from USDA FS International Programs May, 2009.
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Susan Cordell, Ph.D. Research EcologistInstitute of Pacific Islands Forestry, PSW with assistance from USDA FS International ProgramsMay, 2009 The Institute of Pacific Islands Forestry: Research Approaches to Invasive Species Issues and Restoration of Ecosystem Processes in Hawaii and the Pacific
OUR MISSION;Through research, education, and demonstration, we provide scientific and technical information needed to restore, protect, and sustain forests of the Pacific for purposes of conservation and utilization
Natural dispersal over 4.1 million years accounts for 272 introductions and gave rise to the Hawaiian flora FLOWERING PLANTS Species 1304 Endemic (90%) 1160 Extinct 106 T/E 282 FERNS Species 150 Endemic (70%) 105 Clermontia hawaiiensis (Lobeliaceae)
HAWAIIAN PLANT INTRODUCTIONS Polynesians (300 AD): 32 species naturalized Post Capt. Cook (1778): >4600 introductions 1100 naturalized >100 invasive
Forest Service emphasis on the threats of invasive species: "Public lands have become the last refuge for endangered species—the last place where they can find the habitat they need to survive. If invasives take over, these imperiled animals and plants will have nowhere else to go.”- Forest Service Chief Dale Bosworth. Vulnerabilities of Pacific Islands • Low species diversity but high endemism (e.g., 90% of plants and 98% of insects in Hawai`i). • Island endemics have small populations with limited distributions. • Over 476 internationally recognized T&E species • Polynesia-Micronesia is an international biodiversity hotspot Pacific Islands presents special challenges • Control costs for invasive species can be very high for small economies • Increased global trade and travel in the Pacific increases introductions • Introduced grasses increase the risk of fire in some ecosystems • Invasive species & disease causing organisms live and breed continuously in tropical climates
IPIF's Approach to addressing Invasive Species in the Pacific Collaborative, multi-disciplinary efforts including: • Risk Assessment • Detection of distribution and rates of spread • Impacts - both ecological and economic • Bio-Control • Education, Outreach, and Technical Transfer • Restoration of invaded ecosystems
Invasive Species Risk Assessments Hawai`i-Pacific Weed Risk Assessment (HPWRA) Denslow and Daehler The HPWRA identifies high-risk species, allowing us to make informed decisions that reduce the economic and ecological harm caused by invasive plants in Hawai`i and other Pacific Islands. ADVANTAGES Predictive Documented Objective Verifiable Transparent Repeatable Uses information on: • Climate suitability • Reproductive & growth characteristics • Invasive behavior where introduced elsewhere • Noxious characteristics • Feasibility of control More than 500 species evaluated Web accessible data base: www.botany.hawaii.edu/faculty/daehler/wra
HPWRA Predicted Pest or Evaluate Further Low Risk Naturalization in priority areas? Naturalization in priority areas? NO YES NO YES Widely planted for long time? NO YES L H(HPWRA) Field Evaluation Field Evaluation L(HI)
HPWRA Predicted Pest or Evaluate Further Low Risk Naturalization in priority areas? Naturalization in priority areas? NO YES NO YES Widely planted for long time? NO YES L H(HPWRA) Field Evaluation Field Evaluation L(HI)
HPWRA Predicted Pest or Evaluate Further Low Risk Naturalization in priority areas? Naturalization in priority areas? NO YES NO YES Widely planted for long time? NO YES L H(HPWRA) Field Evaluation Field Evaluation L(HI)
Step 2. Document adverse ecological or economic impacts in Hawaii. The Hawaii Exotic Plant Exotic Plant Evaluation Protocol (HEPEP)
Categories • Documented Invasive • Spreading with self-reproducing populations in natural areas and in priority agricultural and forestry areas. • Documented ecological and economic impacts on these areas. • Red Alert • Predicted to be invasive but insufficient evidence. • Non-invasive • Species in the state for a long time • Not naturalizing in priority areas or • Unable to document ecological or economic impacts in priority areas.
Detection of invasive species distributions and rates of spread Long-term collaboration with Carnegie Institute of Washington, Dr. Greg Asner Detection of strawberry guava in native forests of Hawai`i (Asner et al., in press) 3-D imaging of invasive tree species (reds-pinks) and native Hawaiian lowland rainforest (greens) (Asner et al.)
Restoration Research approach • Quantify key ecosystem parameters indicative of the health or ecological integrity of pacific Island forests • Experimentally manipulate degraded landscapes to test the feasibility of re-creating these parameters through restoration • Conduct research that will provide information on how to increase ecosystem resilience and resistance to disturbance
Further degraded, damaged or destroyed state(s) Dynamic Natural Ecosystem Degrading land use activities Degraded Ecosystem State Potential Natural Ecosystem Passive Restoration Successful Restoration Misinterpretation of Ecosystem Needs New Ecosystem Trajectory (ecosystem in a “transformed” state) Active Restoration • Failure
Hawai‘i’s unique challenges require innovative restoration techniques. Passive restoration and overcoming barriers to restoration may not be as successful in Hawai‘i’s dry forests as in other tropical dry forests.
Guided Restoration in remote islands through integration of ecological concepts • Competition theory and ecosystem resistance to re-invasion • Can we manipulate plant assemblages with competitive traits? • Succession and ecological trajectories • Can we design novel trajectories in highly degraded sites?
High Grass Control Amendments (seeding or outplants) Fast-growing vines Slow-growing species Restoration Input Index Favorable micro-climate Low 1 2 Native weedy shrubs 3 Time Period Intact Canopy, Disturbed Understory
High Grass Control Amendments (seeding or outplants) Low Intact Canopy, Disturbed Understory Restoration Input Index Sustainability ? 1 2 3 Time Period
High Fast-growing natives Grass Control Amendments (seeding or outplants) Restoration Input Index Low 1 2 3 Time Period Degraded, Transformed, no Canopy Trees
Degraded, no Canopy Trees High Grass Control Amendments (seeding or outplants) Restoration Input Index Low 1 2 3 Time Period
High High Grass Control Grass Control Amendments (seeding or outplants) Amendments (seeding or outplants) Restoration Input Index Restoration Input Index Low Low 1 2 3 1 2 Time Period 3 Time Period Intact Canopy, Disturbed Understory Degraded, no Canopy Trees
Summary: • Tropical forests in remote islands face unique invasive species and restoration challenges • Restoration must account for ecosystem level changes resulting from invasive species • The utilization of ecological concepts in restoration practices will likely enhance restoration goals