Population and Community Assembly Patterns Related to Remnant Bull Kelp (Nereocystis luetkeana) Forests Following a Catastrophic Decline

Presenter: Vinicius Souza

Co-Presenter(s):
Dr. Hughes

Presenter Status: Graduate student

Academic Year: 22-23

Semester: Spring

Faculty Mentor: Brent Hughes

Department: Biology

Funding Source/Sponsor: Other

Other Funding Source/Program: Personal Grant

Abstract:
As the number of climate driven events increase, the persistence of many marine ecosystems become progressively more vulnerable. Additionally, population dynamics, larval production and demographic connectivity are likely to become more variable as the climate changes. Temperate kelp forests are known to be some of the most productive ecosystems in the world and provide a wide range of ecosystem services (habitat structure, food source, carbon sequestration, sedimentation, storm buffering etc), yet are susceptible to collapse when temperatures and physiological demands increase. In northern California, a series of perturbations, including a record-breaking Marine Heatwave (MHW) has led to a catastrophic decline of these iconic and historically stable forests. Although many kelp forests have shifted to sea urchin barrens, observational and survey data shows there were certain locations (herein by referred to as patches) where kelp populations persisted. However, the regional factors that influenced the persistence of these patches following an ecological catastrophe are not well understood. In this study, I examine population and community assembly patterns related to remnant patches following the drastic decline of northern California kelp forests and assess if the presence of canopy and subcanopy kelp influences the recruitment of macroinvertebrates at two spatial scales: local and regional. To test these patterns, I quantified the abundance and composition of canopy and subcanopy kelp, urchins, abalone, and sea stars at 9 sites that represent a gradient of bull kelp density in addition to the monthly recruitment of larvae and juveniles at 2 sites.