I am back from the Poweshiek Skipperling workshop in Winnipeg. I drove, part of the way with Robert Dana from Minneapolis sharing those duties. It was quite an adventure.
There will be some formal information coming out from this workshop, and I hope to post it when it comes out. I am only going to give a very broad outline here.
Oarisma poweshiek is a prairie obligate butterfly—it seems to occur only in original prairie lands. Until recently it had been considered relatively stable within those areas. Recent trends, however, have been alarming. It seems to have suddenly disappeared from areas it was known to occur, particularly in Iowa and Minnesota. It still can be found in fairly good (though recently reduced) numbers in the one area it is known from in Manitoba, and from the fen areas where it occurs in Michigan.
There was some discussion about whether the butterfly has actually disappeared from the areas where it has not been found or whether it is just undergoing the “bust” portion of a normal “boom or bust” life cycle. The consensus seemed to be that it was indeed gone from these areas, but that comes with a great deal of uncertainty and there is a need for more surveys.
Causes of the decline were discussed. Those may include management by prescribed fire, pesticide applications (particularly episodic responses to soybean aphid infestations), predation or competition by invasive species, particularly the recently overly abundant Asian multicolored ladybeetle, Harmonia axyridis, weather or climate events, or unknown factors. I came away with the impression that the consensus was that no one factor could explain all of the decline, and that there are substantial unknowns
There were a number of roundtable discussions regarding what needs to be done to conserve the species. I think that the general conclusion was that not enough was known about the life cycle of the butterfly, and that conservation and recovery efforts should concentrate on learning more about the needs and preferences of the butterfly.
I was very impressed by the knowledge, intelligence, dedication, and professionalism of the people involved in the workshop. I felt that a lot was accomplished and hopefully there will be more action in the future.
When more information comes out from the workshop I will let people know where to find it.