Bay Checkerspot Butterfly

By Carla Pangan

Status: 
The bay checkerspot butterfly was listed as threatened under the Endangered Species Act in 1987 and continues to be listed as such today. 

About:

The bay checkerspot butterfly is a medium sized butterfly, distinguishable by the black bands along the veins of the wings’ upper surface. Contrasting these bands are bright yellow, red, and white spots dispersed throughout its wingspan of 2 inches. Bay checkerspot butterflies can lay up to 250 eggs during March and April which they lay on host plants pictured below. After about 10 days, the eggs hatch. The next 2 weeks are devoted to the larvae’s development and continuous shedding. Before the host plants dry from summer’s heat, larvae go under rocks or cracks in the soil to diapause in the summer until the end of summer. In the fall, larvae continue to feed and eventually develop into adults with lifespans of 10 days. 

               owl's clover                                                     dwarf plantain

Changes in Geography and Population:

Bay Checkerspot butterfly distribution

Dependent on plants that thrive in Serpentine soil, bay checkerspot butterflies are mostly found in California where this low-nutrient soil is abundant. Historically, Bay Checkerspot butterflies are known to inhabit various areas around the San Francisco Bay from the San Jose mountains to the San Francisco Peninsula. However, population levels of these butterflies hit a record low in the ‘80s and continue to dwindle today. Now populations are restricted to areas in San Mateo and Santa Clara counties. Habitats are found in patches like islands, isolated by unsuitable habitat and urban development.

Serpentinite: what Serpentine soil is composed of

Main Threats and Cause of Listing:

Many factors contribute to the overall decrease of bay checkerspot butterfly populations--all of which can be traced back to anthropogenic sources. Some are more obviously elicited by humans such as the use of pesticides, illegal collecting, and vehicles strikes. Other factors include extreme weather, air pollution, and invasive species and are more indirectly caused by humans.

The two major threats to bay checkerspot butterflies are habitat loss and fragmentation, and invasive species. As urban development continues in the Bay Area, more land is converted for human use. In Santa Clara, for example, land habitable by these butterflies is being used as a landfill. However, even mere human presence in these areas disrupts and fragments their habitats. With less habitable area, there are less butterflies.

Additionally, an increase in human activity results in increased levels of smog, air pollution, and most notably nitrogen. This greatly impacts the native plant species these butterflies depend on as a food source and shelter for their eggs. The owl's clover and dwarf plantain, to name two, are accustomed to Serpentine soil. As we burn fossil fuels for our energy needs, nitrogen levels in the air are augmented. This nitrogen seeps into the soil and increases the soil's fertility making it unsuitable for key native plants but optimal for the spread of Eurasian grasses and other non-native invasive species. With less suitable and further fragmented habitat, Bay checkerspot butterflies decrease in fitness and number.

Another human induced cause of the bay checkerspot butterfly's decline is the use of pesticides. The survival of larvae is reliant on the survival of its host plants which provide it shelter and food. Caterpillars must grow as much as possible in the spring before their host plants dry out so that they can hibernate through summer. Pesticides poison these host plants and threaten the survival of these bay checkerspot butterflies if they are unable to develop in time for summer.

Recovery Plan: 
The recovery plan created by US Fish and Wildlife Services combines multiple approaches to appropriately address the many various causes of bay checkerspots' decline. Of top priority is habitat protection. Habitats will be prioritized based on size, quality, and location relative to other habitats. Buffer zones will also be included as necessary. 

Populations will be monitored through mark-and-recapturing of larvae to provide a better understanding of Bay Checkerspot butterfly demographics. These estimates done with larvae will then be extended to estimate adult population sizes. 

Reestablishment will also occur taking 2 forms: reestablishment of bay checkerspot populations and reestablishment of vegetation. 

Lastly, the final part of the recovery plan is public outreach. Public outreach will aim to address the fragility of San Francisco Bay Area serpentine grassland ecosystems and ways citizens can be proactive in its protection.

What you can do:
Much of what currently threatens Bay Checkerspot butterflies are effects of climate change. However, we can slow climate change with simple lifestyle adjustments to reduce our ecological footprints. Some of these adjustments can include lessening our electricity use or limiting our meat consumption. One that more directly benefits Bay Checkerspot butterflies is to drive less and better adhere to speed limits. Ammonia and NOx emissions are directly proportional to speed, increasing exponentially with increasing speed. If we can limit our road emissions, we can maintain the chemistry of the Serpentine soil, a critical factor to the survival of these butterflies

Even more directly, you can volunteer to pull weeds of invasive species and replant seeds of native species. When invading plants are removed, native plants can reestablish and more habitat will be available for the survival of Bay Checkerspots.




Being vocal and active in your community is also important. Each of our voices can stress to our leaders how important it is for land development and management to be both sustainable and appropriate. Halting continued fragmentation or destruction of Bay Checkerspot butterflies' habitats is a political matter shapable by us. Especially if you live in the Bay Area, your input is crucial and stronger than you may realize. After all, all big changes are made up of little changes. 


Bay Checkerspot butterfly populations remain unstable but if we combine personal and political effort, we may be able to secure the revival of Bay Checkerspot butterflies.

References: 

-http://www.fws.gov/sacramento/ES_Kids/Bay-Checkerspot-Butterfly/es_kids_bay--checkerspot-butterfly.htm
-http://ecos.fws.gov/docs/recovery_plan/980930c_v2.pdf
-http://www.friendsofedgewood.org/bay-checkerspot-butterfly

-http://www.xerces.org/bay-checkerspot/
-www.biologicaldiversity.org/species/invertebrates/Bay_checkerspot_butterfly/index.html