U.S. Fish and Wildlife Service
134 Union Boulevard
Lakewood, Colorado 80228
April 26, 2010
Contacts: Susan Linner 303-236-4774
Diane Katzenberger 303-236-4578
Endangered Species Act Protection for the Susan’s Purse-making Caddisfly
Is Not Warranted
The U.S. Fish and Wildlife Service announced today it has completed a status review of Susan’s purse-making caddisfly, a small moth-like insect, and has determined it does not warrant protection as a threatened or endangered species under the Endangered Species Act. The Service made this finding after a thorough review of all the available scientific and commercial information regarding the status of Susan’s purse-making caddisfly and the potential impacts to the species.
Susan’s purse-making caddisfly has only been documented at three sites: Trout Creek Spring in Chaffee County, Colorado; High Creek Fen in Park County, Colorado; and Jaramillo Creek in Valles Caldera National Preserve, New Mexico.
The Service assessed potential impacts to Susan’s purse-making caddisfly including grazing, hazardous fuels reduction using prescribed burns and logging, roads, dewatering of spring habitats, recreational activities, climate change, collection, disease or predation, the inadequacy of regulatory mechanisms, genetic effects from small population size, and naturally occurring random events. The Service does not believe Susan’s purse-making caddisfly is in danger of extinction throughout all or a significant portion of its range because of current or future impacts.
Because of the restricted distribution and narrow habitat requirements of Susan’s purse-making caddisfly, grazing could have a negative impact on the species. Despite this possibility, no grazing impacts are apparent in the immediate vicinity of Trout Creek Spring or at Valles Caldera National Preserve. There is no grazing around High Creek Fen where Susan’s purse-making caddisfly occurs. Grazing is not expected to impact Susan’s purse-making caddisfly in the foreseeable future at any of the known sites due to management practices currently in place and that are expected to continue.
Proposed logging activities and prescribed burning activities in the Trout Creek Spring watershed could potentially have negative impacts on Susan’s purse-making caddisfly by increasing the sediment load in Trout Creek. However, these activities are not occurring at the present. Even if sediment transport does increase as a result of future logging and burning activities, it is unknown if the sediment will be deposited in Trout Creek Spring to an extent that would affect Susan’s purse-making caddisfly. The Valles Caldera National Preserve is still experiencing some erosion from logging-related roads developed before 1972, but Jaramillo Creek is in good ecological condition and continues to improve.
Prescribed burning does not take place at High Creek Fen. At Valles Caldera National Preserve, natural fire patterns were disrupted in the late 1800s with the introduction of livestock and intentional fire suppression. Natural fires have not occurred in the Preserve in many years and prescribed fires have been limited.
In addition to roads associated with hazardous fuel reduction projects, Trout Creek Spring may be impacted by Highway 285 which runs within 100 feet of the eastern side of Trout Creek Spring and crosses High Creek Fen on the western side. Roads accumulate a variety of contaminants including brake dust, heavy metals, and organic pollutants which can be carried into streams by overland runoff. Based on the condition of the vegetation around the spring, there is no indication of any effects from the sand/salt mixture used during the winter season. There is no evidence that roads in and near Susan’s purse-making caddisfly habitat are negatively impacting the water quality or habitat. Two maintained roads near Jaramillo Creek in the Valles Caldera National Preserve may contribute sediment into the creek during rainstorms. The roads are not open during the winter and no salt, chemicals or herbicides are used along them, so road contaminants are not an issue around the known Susan’s purse-making caddisfly location in the Valles Caldera National Preserve.
Alterations in stream hydrology and water chemistry due to increased groundwater use and water diversion can have a dramatic impact on stream habitat. Reduced flows can lead to changes such as decreased water depth, increased sedimentation, and altered water temperature and chemistry thereby influencing microinvertebrate populations. At this time, the Service does not have data showing that the quantity of water has been lowered or that the current water withdrawals are impacting Susan’s purse-making caddisfly habitat or will impact Susan’s purse-making caddisfly in the foreseeable future.
Population growth in central Colorado has led to increased numbers of recreational users. Off-road vehicle (ORV) impacts have been documented at Trout Creek Spring. However, ORV use is restricted to existing roads and the likelihood of future ORV use impacting the Susan’s purse-making caddisfly habitat in Trout Creek Spring is low due to fences above and below the spring as well as steep slopes down to the spring.
Climate change could pose a problem to Susan’s purse-making caddisfly if water levels, water temperature, or other habitat variables that affect the caddisfly change as a result of global warming. However, the mid-to-high elevation of Susan’s purse-making caddisfly habitat may shield it from climate change effects. Furthermore, there is currently no model that can predict climate change effects at a local enough scale to ascertain whether climate change is, or will become, a threat to the Susan’s purse-making caddisfly.
There is no evidence that collection, disease, or predation have been or will be a threat to Susan’s purse-making caddisfly.
The Service believes that lands currently managed by the Colorado State Land Board, the U.S. Forest Service, The Nature Conservancy, and the Valles Caldera National Preserve adequately provide for the protection of the Susan’s purse-making caddisfly.
There is no evidence to suggest that genetic problems exist due to small population size or that naturally occurring random events will threaten or endanger Susan’s purse-making caddisfly now or in the foreseeable future.
The petition to list the Susan’s purse-making caddisfly as endangered under the Endangered Species Act was submitted by the Xerces Society, Center for Native Ecosystems, WildEarth Guardians, and Western Watersheds Project.
For more information regarding Susan’s purse-making caddisfly, please visit the Service’s web site at: http://www.fws.gov/mountain-prairie/species/invertebrates/SusansPurseMakingCaddisFly/index.html
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