Linking Nearshore Kelp Forest Dynamics to Sandy Beach Ecosystems

Award Period
to
Award Amount
$1,027,987
Agency Name
National Science Foundation
Award Number
OCE-1458845
PI First Name
Jenifer
PI Last Name
 Dugan
CO-PI
Robert Miller
J. Carter Ohlmann
Area/s of Research
Ecology and Evolution
Abstract

The proposed research seeks to understand trophic connectivity between a donor ecosystem, kelp forests, and a recipient ecosystem, sandy beaches, with two primary goals: 1) an evaluation of how variation in kelp wrack input affects patterns and processes in beach ecosystems and 2) a quantitative understanding of trophic connectivity through physical transport and input of drift kelp from kelp forests to sandy beaches. The project begins with two years of intensive work at a well-studied kelp forest, Mohawk Reef, and 10 km of adjacent coastline, where we will measure community structure over time in response to variability in kelp inputs. To assess effects of variation in wrack input on ecosystem function, we will measure kelp consumption and secondary production rates of consumers. We will directly observe kelp fate and transport from Mohawk Reef using complimentary approaches: 1) tracking kelp plants tagged using GPS; and 2) tagging large numbers of kelp plants (2000) with ’drift cards’. Ending distributions of recovered drift cards and drifter tracks along the shoreline will then be computed. These data will be used to inform and validate a kelp forest-to-beach drift kelp transport model based on numerical simulations of coastal surface currents from the Regional Oceanic Modeling System (ROMS). Using predicted kelp beaching rates from this model run regionally, we will then survey community structure and kelp wrack at a larger set of beaches spanning 100 km of the southern California shoreline to test the generality of our results. This combination of fate and transport observations, beach sampling, and modeling will allow characterization of temporal variability in kelp resource inputs and the consequences of this variability for community structure and function of recipient beach ecosystems.