Draft Environmental Assessment Lehua Island Ecosystem Restoration Project April 2017 Co-Lead Agency
Total Page:16
File Type:pdf, Size:1020Kb
Draft Environmental Assessment Lehua Island Ecosystem Restoration Project April 2017 Co-Lead Agency: U.S. Fish and Wildlife Service Hawaiʻi Department of Land and Natural Resources, Division of Forestry and Wildlife Cooperating Federal Agencies: U.S. Department of Homeland Security, U.S. Coast Guard U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center i Executive Summary Lehua Island is a 115 hectare island located 1.2km off the northern shore of Niʻihau (a privately owned, 18,650 hectare island). Lehua is a state-designated seabird sanctuary managed by the Hawaiʻi Department of Land and Natural Resources (DLNR) and federally owned by the U.S. Coast Guard (USCG). Lehua is one of Hawaiʻi’s most important seabird colonies because of its size and height above sea level. It also offers an opportunity for restoring an island ecosystem in the main Hawaiian Islands. DLNR-Division of Forestry and Wildlife (DOFAW), in conjunction with federal sponsors U.S. Fish and Wildlife Service (USFWS), technical partner Island Conservation (IC), and the cooperating members of the Lehua Island Restoration Steering Committee (LIRSC) are proposing to complete the eradication of rats from Lehua Island so further restoration efforts can move forward in the future. The LIRSC is a multidisciplinary stakeholder body including representatives from DOFAW, USFWS, the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services (USDA), U.S. Coast Guard (USCG), National Tropical Botanical Garden (NTBG), the owners of Niʻihau, and IC. In 2005, DOFAW and the USFWS embarked on a plan to restore Lehua Island. As part of the compliance for the action proposed in the plan, both federal and state Environmental Assessments (EA) were submitted, commented on by the public, and resulted in a Finding of No Significant Impact (FONSI) for both the 2005 Lehua EAs and the supplemental EAs in 2009. The alternatives approved in the EAs were followed and the actions resulted in the complete eradication of rabbits from Lehua in 2006 and an incomplete eradication of rats in 2009. The purpose of the proposed action is to eradicate non-native rats from Lehua and maintain its rodent-free status, which would facilitate the restoration of the natural island ecosystem. The proposed action could improve seabird nesting habitat and could aid in the recovery of rare endemic seabirds such as band-rumped storm petrels, Hawaiian petrels, and Newell’s shearwaters, and native coastal plants, and insects. The proposed action is not anticipated to have any significant negative environmental effects. The proposed action involves the aerial broadcast of bait pellets containing rodenticide into all potential rat territories on Lehua Island. Rat eradication would occur in the summer dry season to maximize the probability of success by targeting the rats when food resources are lowest and rat abundance is declining. Conducting the operation during this period would also minimize the risk of rain washing rodenticide pellets into the ocean. ii DOFAW, USFWS, and IC have conducted extensive scoping of the proposed action since 2005, and additional scoping following the 2009 incomplete eradication attempt. As a result of comments from interested public, Federal and State agencies, and conservation groups, DOFAW, USFWS, and IC identified a number of environmental issues. These issues are: 1) restoration efficacy; 2) impacts on non-target species; 3) increase in weed abundance caused by rat eradication; 4) impacts on cultural resources; 5) impacts on human health and safety; and 6) introduction of non-native species caused by project activities. Following the 2009 rat eradication attempt, there was a coincidental fish mortality event reported on Niʻihau and a dead whale calf also was found around the same time. Several tests of the affected fish were done and showed no rodenticide in tissues. Nonetheless, further analysis and research is included in this document to address impacts to marine species. To address these environmental issues, the USFWS and DOFAW prepared three alternatives. Each alternative was developed to respond to the environmental issues identified. USFWS and DOFAW also considered many other alternatives and methods to eradicate rats on Lehua Island, but rejected the methods that failed to meet the purpose and need of the project. Within this Draft EA, USFWS and DOFAW also describe the affected environment of the project. This section describes what is currently known about the status and trend of affected island resources, including the physical features of the island, and its terrestrial and marine resources. There is also an analysis of the environmental consequences that could occur should any of the alternatives presented be chosen for implementation, and a description of proposed mitigation measures. The USFWS-PIFWO Field Supervisor is responsible for the final decision on the proposed action, in addition to plan implementation and monitoring. iii Table of Contents Executive Summary .................................................................................................... ii Table of Contents ...................................................................................................... iv Glossary of Terms ..................................................................................................... viii List of Acronyms and Abbreviations ............................................................................ x 1. Background ....................................................................................................... 12 1.1 Introduction .............................................................................................. 12 1.2 Overview of the Lehua Island Ecosystem Restoration Project Environmental Assessment of 2005 .............................................................................................. 12 1.3 Overview of the Lehua Island Ecosystem Restoration Project Supplemental Environmental Assessment of 2008 ....................................................................... 14 1.3.1 Factors Evaluated as Potential Causes of the 2009 Rat Eradication Failure ... 14 1.4 Consequences of Rabbit Eradication .......................................................... 15 1.5 Plant Restoration ....................................................................................... 15 1.6 Feasibility Assessment ............................................................................... 16 2. Purpose and Need ............................................................................................. 18 2.1 Introduction .............................................................................................. 18 2.2 Purpose of Action ...................................................................................... 18 2.3 Need for Action ......................................................................................... 18 2.3.1 Follow-up to 2005 and 2009 Eradication Efforts ............................................. 18 2.3.2 Impacts of Non-Native Predators on Islands ................................................... 18 2.3.3 Impacts to Islands from Non-native Rodents .................................................. 18 2.3.4 Rodent Impacts in Hawaiʻi ............................................................................... 20 2.3.5 Lehua and Invasive Mammals .......................................................................... 21 2.3.6 Rodent Eradications on Islands ........................................................................ 23 2.4 Scope of Analysis ....................................................................................... 24 2.5 Authority for Action and Regulations Governing Action ............................. 24 2.5.1 Authorizing Federal laws, Executive Orders and Supporting Agency Guidelines24 2.5.2 Hawaiʻi State Laws and Agencies that Apply to or Support the Proposed Action ................................................................................................................................... 27 2.6 Rodenticide Label and Permit Requirements .............................................. 29 2.6.1 EPA-Approved Labels ....................................................................................... 29 2.6.2 Permits ............................................................................................................. 29 2.7 Purpose of this Analysis ............................................................................. 30 3. Alternatives ...................................................................................................... 31 3.1 Alternative Development........................................................................... 31 3.2 Internal Scoping and Public Involvement.................................................... 31 3.3 External Scoping ........................................................................................ 32 3.4 Alternatives Being Considered ................................................................... 33 3.4.1 No-Action – Alternative 1 ................................................................................ 33 iv 3.4.2 Action Alternative 2: Rat Eradication with Diphacinone (50ppm), Followed by Brodifacoum (25ppm) if Necessary. ......................................................................... 33 3.4.2.1 Summary of Actions: ................................................................................