Ancestral and contemporary intertidal mariculture practices support marine biodiversity in the northeast Pacific

Abstract

The cultivation of seafood now outpaces extraction from wild populations. This novel state in the history of human-marine ecosystem interactions highlights the importance of identifying cultivation practices that balance production and conservation. Here, we test the hypothesis that two shellfish cultivation practices, one that spans decades and the other millennia, bolsters habitat complexity, which increases epifaunal (surface) invertebrate diversity. To do so, we conducted multiple surveys of 24 First Nations clam gardens, shellfish aquaculture farms, and non-walled or unmodified beaches along the west coast of Canada. We show that habitat alterations specific to each cultivation practice restructure epifaunal communities at several ecological and spatial scales. Distinct communities within clam gardens and shellfish farms are a function of habitat complexity at 25–50 and 50–100 cm resolutions and changes in the amount of gravel, bivalve shells, and seaweeds. Our findings highlight how resource cultivation can contribute to achieving sustainable human-ecosystem interactions.