Plan for the Controlled Propagation, Augmentation, and Reintroduction of Dakota skipper (Hesperia dacotae) April 30th 2017 Authors: Phil Delphey, Fish & Wildlife Biologist, U.S. Fish & Wildlife Service, Bloomington, MN Erik Runquist, Butterfly Conservation Biologist, Minnesota Zoo, Apple Valley, MN Cale Nordmeyer, Butterfly Conservation Specialist, Minnesota Zoo, Apple Valley, MN Plan for the Controlled Propagation, Augmentation, and Reintroduction of Dakota skipper 2017 Contents I. Executive Summary ............................................................................................................................... 4 II. Introduction .......................................................................................................................................... 5 III. Definitions of Terms Used in this Plan .............................................................................................. 5 IV. Justification for Captive Rearing, Augmentation and Reintroduction .............................................. 6 A. Status of the species ......................................................................................................................... 6 B. Likely Population Trends ................................................................................................................. 10 C. Threats ............................................................................................................................................ 11 D. Contributions to the Species’ Recovery .......................................................................................... 12 E. Summary of CBSG Workshop– Dakota Skipper Working Group ..................................................... 12 F. Reintroduction Justification ............................................................................................................ 13 V. Goals, Objectives and Actions ............................................................................................................. 15 VI. Basic Biological Knowledge ............................................................................................................. 17 A. Dispersal .......................................................................................................................................... 17 B. Dakota Skipper Habitat Descriptions .............................................................................................. 18 C. Habitat Needs by Life Stage ............................................................................................................ 20 D. Climate ............................................................................................................................................ 21 VII. Feasibility and Design...................................................................................................................... 22 A. Selected Founder Populations and Genetic Considerations ........................................................... 22 B. Animal welfare ................................................................................................................................ 23 C. Disease and parasite considerations .............................................................................................. 23 D. Social feasibility ............................................................................................................................... 24 E. Regulatory compliance ................................................................................................................... 25 F. Resource availability ....................................................................................................................... 26 G. Disaster preparedness .................................................................................................................... 27 VIII. Risk Assessment .............................................................................................................................. 27 A. Risk to source populations .............................................................................................................. 27 B. Ecological Risk ................................................................................................................................. 30 C. Disease risk...................................................................................................................................... 33 D. Associated invasion risk .................................................................................................................. 34 E. Gene escape and population genetic consequences ...................................................................... 34 F. Socio-economic risks ....................................................................................................................... 34 G. Financial risks .................................................................................................................................. 35 2 Plan for the Controlled Propagation, Augmentation, and Reintroduction of Dakota skipper 2017 H. Risks of inaction .............................................................................................................................. 36 IX. Release and Implementation .......................................................................................................... 36 A. Selecting Collection Sites ................................................................................................................ 36 B. Collections and Ex situ Rearing ....................................................................................................... 36 C. Selecting Release Sites .................................................................................................................... 37 D. Release strategy .............................................................................................................................. 39 E. Disposition of excess progeny ......................................................................................................... 42 X. Monitoring and continuing management ........................................................................................... 42 A. Demographic performance ............................................................................................................. 42 B. Behavioral monitoring .................................................................................................................... 45 C. Ecological monitoring...................................................................................................................... 45 D. Genetic monitoring ......................................................................................................................... 46 E. Health and mortality monitoring .................................................................................................... 46 F. Socio-economic monitoring ............................................................................................................ 46 G. Continuing Management ................................................................................................................ 47 H. Habitat management ...................................................................................................................... 47 XI. Exit strategy .................................................................................................................................... 48 XII. Dissemination of Information ......................................................................................................... 49 XIII. Literature Cited ............................................................................................................................... 50 XIV. Appendix A- Criteria for Reintroduction and Founder Site Selection ............................................. 53 XV. Acknowledgements ......................................................................................................................... 60 3 Plan for the Controlled Propagation, Augmentation, and Reintroduction of Dakota skipper 2017 I. Executive Summary The Dakota skipper, Hesperia dacotae, has vanished from over 74% of once known occupied sites and was listed under the Endangered Species Act as Threated in 2014 (USFWS 2014). This species occurs nowhere else but remnant tall grass prairies. Suitable habitat for Dakota skippers has become largely isolated and fragmented. Natural dispersion between sites is highly unlikely without anthropomorphic intervention. For sites where Dakota skippers have become extirpated, reintroduction is the only option to restore the species to where it once was. This document outlines a plan to reintroduce Dakota skippers from the Minnesota Zoo’s Prairie Butterfly Conservation Program to The Nature Conservancy’s (TNC) Hole-in-the-Mountain (HIM) Preserve (Lincoln Co., MN) beginning in 2017. The breeding program at the Minnesota Zoo began in 2013 strictly as an insurance program to preserve genetic diversity. In addition to breeding Dakota skippers at the Zoo, the ex situ population has been supplemented by wild-collected eggs annually from populations in northeastern South Dakota and northwest Minnesota. The Prairie Butterfly Conservation Program has successfully grown this ex situ Dakota skipper population each year, to the point where the insurance program can be maintained