For special education purposes, charter schools have a unique ability not available to the other schools within their district authorizer: Charter schools can be either a school of the district, or they can be an independent member of a SELPA.  

School of the District

A charter that is deemed a school of the district for special education purposes is treated as any other school within the district authorizer. The school district, not the charter, is the member of the SELPA, and retains all the rights and responsibilities as a member. For example, special education funding is allocated to the school district, not the charter school. However, the school district and the charter may have their own funding allocation through their MOU. 

Member of a SELPA

A charter may become an independent member of a SELPA. A charter may apply for membership in its authorizer's SELPA, or join one of several charter only SELPAs in the State. Once a member, the charter retains all the rights and responsibilities as a member. For example, as a member, the charter receives special education funding allocated by the SELPA. 

The California Charter Schools Association has additional information regarding charters as schools or members here.

References

California Education Code 47646
Charter School Funding Types