Ecological Society of America community listserve, good for positions as graduate students, volunteers, and technicians:
http://community.esa.org
Society for Conservation Biology’s job page:
http://careers.conbio.org/jobs/
The Nature Conservancy’s Career page:
http://careers.nature.org
Pathways program for jobs in government:
https://www.usajobs.gov/Help/working-in-government/unique-hiring-paths/students/
Conservation & Land Management Internship Program (summer):
https://www.clminternship.org/
National Science Foundation Research Experiences for Undergraduates (mostly summer)
http://www.nsf.gov/crssprgm/reu/
The Ecology, Behavior & Evolution Club at UCSD seeks to provide students with research opportunities and information regarding careers in ecology, behavior & evolution (EBE). The group also serves as a social nexus for students with EBE interests, and provides an organizational structure to promote volunteer activities. Interested undergraduates of any major are welcome to come to the monthly meetings to learn about local ecological projects. Please keep up with happenings via their Facebook Group, just search for the Undergraduate Ecology, Behavior & Evolution Club at UCSD.