Ottoe Skipper - Wisconsin Department of Natural Resources

WISCONSIN DNR SPECIES STATUS ASSESSMENT WORKSHEET
Ottoe Skipper (Hesperia ottoe) page 6 of 10
Threats
12. Known threats:
Historic loss, degradation, and fragmentation of the prairie landscape have been the
primary factors contributing to the decline and current vulnerability of Ottoe skipper
populations, and continued habitat loss, degradation, and fragmentation are the greatest
potential threats to future populations. Threats to habitat quality and the availability of
critical resources (e.g., nectar plants, larval food plants) include indiscriminant use of
herbicides, invasive exotic species, and encroachment by woody vegetation (native and
exotic). Fire, grazing, and haying can play important roles in maintaining and shaping
prairie ecosystems, so the complete absence of these processes can constitute a threat to
the extent and quality of prairie remnants. However, they can also pose direct and indirect
threats to Ottoe skippers depending on their timing and intensity. Larvae are extremely
vulnerable to direct mortality from fires when they are using aboveground shelters, and
improperly timed fires, grazing, and haying can impact the availability of nectar and
larval food resources at critical times. Other more direct threats to Ottoe skippers can
include extreme weather (e.g., harsh winters, late frosts, unusually cool and wet growing
seasons, and severe storms), indiscriminant use of insecticides, disease, and predation. A
reduction in fitness resulting from genetic isolation may also pose a long-term threat
(Selby, 2005). In addition, some Wisconsin populations have experienced collecting
which may have exacerbated the above threats. For example, one was collected at the a
site in 1996 when three was the highest number reported out of 6 years of reported survey
numbers. Another example comes from a site where it was reported that the species was
"collected multiple times by multiple observers". One of those collections took place in
1996 after 2 previous years of low numbers reported (9 total for 3 surveys in 1995, and 6
total for 3 surveys in 1994). With the precipitous decline in the last 20 years, few
remaining known populations with few individuals per population, collecting could pose
a serious threat in the near future.