Behren's Silverspot Butterfly- Lili LeBaron

Behren’s Silverspot Butterfly

A single Behren Silverspot Butterfly.

 http://drakehs.org/academics/seadisc/endangeredspecies/2010/Daniel%20and%20Alexa/reasons.html

Who is this Behren Silverspot Butterfly?

The Behren Silverspot Butterfly is a sub species of the Zerene Fritillary, or silverspot butterflies. There are 13 species of this family which occur throughout North America. The Behren Silverspot is an average mid-sized butterfly with a 5.5 cm wingspan and has an appearance of golden brown with numerous black spots and lines captivating it's wings. The underside of the wings has a similar brownish orange color and is lined with black lines and distinct silver and black dots. 

Where is the Behren Found?

The Behren original and historic geographic range consisted of six known sites ranging from the city of Mendocino, California, south to Salt Point State Park in Sonoma County California. As of today the range of the Behren has shrunk dramatically and now consists of very few sites ranging from the Point Arena- Manchester State Park in California to the Salt Point State Park in Sonoma County, California. 

The current geographic range of the Behren Silverspot Butterfly. 

https://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=I031

The History of the Behren

Information and history relating to the Behren comes from it's close relative, the Oregon silverspot. The history of the two species is extremely closely related and is the bases most information and historical reference on the Behren. The species is closely tied to the blue violet which the females lay their eggs in the debris of the small and native perennial herb. The violet are common in the western united states where the Behren's range is found. The violet most commonly blooms in the spring and summer and dies by fall and winter. It is an exceptionally important herb for the survival of the Behren Silverspot butterfly. The larvae once hatching create silk pads where they lay in dormancy for the fall and winter seasons. The newly awakened larvae than look hurriedly for the violet herb to feast upon. During the spring the larvae create silk cocoons and enter their five stage transition. Once transitioned the butterflies live for roughly three weeks in which they spend feeding and reproducing. The Behren's tend to feed on nectar from flowers in the sunflower family and often after feeding on the nectar for as long as five minutes will return to the same flower repeatedly. 

The Habitat of the Behren

The habitat of the Behren Silverspot butterfly is a fairly specific type of landscape. The butterflies inhabit coastal terrace prairie habitat in areas of western California. The butterflies require areas near the coast with mild temperatures, frequent summer fog, and a moderate amount of rainfall. In order for the area of landscape to be fit for supporting the species of butterfly it must contain a significant amount of host plants for the caterpillar and enough nectar plants for adult butterflies to feed upon. This plant needed in the area must be the blue violet because it provides the host plant for the larvae. It is also vital for there to be an array of nectar sources available for adult butterflies. The coast range in western California is sustainable for this species because it provides a coastal prairie terrain that has perennial grasses as well as a very common summer fog, making it an extremely suitable habitat for the species. The impact of wind on the species is also a contributor to the habitat needed. The prevalence of wind in the western California coastal areas these butterflies rely on are typically windy, with wind gusts coming from the north. In order for the species to be protected and successful it is important that they have protection from the wind in large trees and shrubs. 

Threats to the Behren

The Behren Silverspot Butterfly, a specialist specie, is endangered due to a few contributing factors. The fact that the species is a specialist and therefore can not live anywhere and requires specific conditions for it's survival makes it's population survival more difficult and easily impacted by enviormental and human impact. There are three main causes that are greatly affecting the species. These include fragmentation, urban development, and the impact of alien species and erosion. The small and centralized population of the specialist species means its survival is easily threatened. Habitat fragmentation is a large reason for the declining numbers of Behren. The Behren is found commonly in large tourist areas where many humans are present observing and being active in the Behren's habitat. The influx of tourist activities has had detrimental affects on the butterfly population. The small area in which the butterfly lives is infused with running and biking trails which break up and fragment the habitat of the butterfly, greatly affecting its survival abilities. It is also seen that because of this human interest in the area and the use of the habitat for walking, running, and biking has lead to the decrease or break down of the blue violet plant, a vital organism for the butterflies survival. Along with habitat fragmentation urban development by human's greatly impacts the butterflies population size. The butterflies habitat being a coastal area makes it much more prone to human impact. Urbanization for tourism in the coastal areas in greatly harming the natural and very specific coastal habitat that the butterflies and larvae rely on. Along with human impact the prevalence of alien species and erosion are also at play in the endangerment of the species. The influx of alien/invasive species such as the Red Martin Weed, English Ivy, and French Bloom are having detrimental affects on the Blue Violet, a critical species for the Behren butterflies survival. Along with the species being impacted by the loss of vital nesting plant for larvae due to invading plant species erosion by overgrazing is also in affect. Overgrazing by cattle and other livestock is creating erosion in the habitat of the butterfly and further destroying Blue Violet blooms making the land available for the Behren increasingly small. All of these factors, many due to human influence, are greatly destroying the population of the Behren Silverspot Butterfly and will continue too unless there is a change in how humans deal with this delicate species. 

Blue Violet plant, a critical part of the Behren's survival. 

http://drakehs.org/academics/seadisc/endangeredspecies/2010/Daniel%20and%20Alexa/photos.html

Endangerment 

The Behren Silverspot Butterfly became endangered in 1997. In 2004 and 2006 surveys were taken of the butterflies during there flight. In 2010 and 2012 more surveys were taken and compared to the 2004 and 2006 baseline population numbers. It became very obvious that there was an extremely serious decline in the number of butterflies. This decline is believed to continue rapidly due to the human and agricultural impact on habitat. 

Point Arena, Mendocino County, California, the largest site of Behren Silverspot Butterflies. 

http://www.americansouthwest.net/california/point-arena/index.html

The Plan

The main priority in helping save the Behren is to protect it's habitat. The U.S. Fish and Wildlife Service's objective to help the species is to "work with partners to protect, maintain, and improve habitat for the butterfly" (Final Recovery Plan for Behren Silverspot Butterfly). The ultimate goal of the recovery plan is to have the butterfly removed from endangered and eventually threatened species list. In order to ensure this plan it enlists creating self-sustaining metropolitan areas in which the historic range of the butterfly is found. Along with this the plan requires reducing threats to the butterflies, conserving the butterflies ecosystem, and keep an eye and monitor the population numbers of the subspecies of butterflies.

In order for the butterfly subspecies to be downlisted to a threatened species there are a few requirements. These include making sure there are four metropolitan areas that become protected sites and closely monitoring the butterfly population in the area annually. There must be a minimum of 4,000 total and 1,000 per site for at least 10 years in order for the species to be downlisted to threatened. 

To take the species off the endangered and threatened list, to delist it, it will require a multitude of criteria. This criteria includes establishing six protected metropolitan sites, two in Sonoma County and four in Mendocino County. All six sites must also all be managed in perpetuity and the threats to the butterflies must be all well controlled by management plans. Lastly it requires that all six sites have a minimum of 1,000 butterflies for at least ten years and an overall 6,000 butterflies over the entire range. There must also be evidence of a stable increasing population over the ten year period. 

Cost and Time

The cost of recovery is estimated to be around $10.5 million and has had a three percent increase to account for inflation. This cost is used to fund operation expenses and to research the historical and potential spots for the species. If the plan is successful and all the criteria is met the species could by downlisted by 2025 and delisted by 2035.

What can be done?

It is important for the public to be informed about the threats to the butterflies and the importance of minimizing those threats and protecting this species. Managers, landowners, and all the public living in the areas populated with the Behren should be aware of their impact on the species and how to minimize it. It is important to be aware of the impact habitat destruction, overgrazing, fragmentation, and urbanization have on the species. The public can protest this overuse of the habitat and human interference in the crucial areas that are home to the endangered species. 

A dead Behren Silverspot Butterfly that was hit by a vehicle. Vehicles and human urbanization such as the building of roads and trails has fragmented the specialist species habitat. 

http://drakehs.org/academics/seadisc/endangeredspecies/2010/Daniel%20and%20Alexa/photos.html

Resources

Service, U.S. Fish and Wildlife. “Behren's Silverspot Butterfly (Speyeria Zerene Behrensii).”Species Profile for Behren's Silverspot Butterfly (Speyeria Zerene Behrensii), U.S. Fish & Wildlife Services, ecos.fws.gov/ecp0/profile/speciesProfile?spcode=I031.

“Background.” Behren's Silverspot Butterfly Homepage, drakehs.org/academics/seadisc/endangeredspecies/2010/Daniel%20and%20Alexa/background.html.

Service, U.S. Fish and Wildlife. “Behren's Silverspot Butterfly Species Profile.” Official Web Page of the U S Fish and Wildlife Service, www.fws.gov/arcata/es/inverts/behrensss/bss_bfly.html.

Recovery Plan 

https://ecos.fws.gov/docs/recovery_plan/20160314_Final%20Behren's%20RP_signed.pdf