Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.

Maintaining food production while sustaining productive ecosystems is among the central challenges of our time, yet, it has been for millennia. Ancient clam gardens, intertidal rock-walled terraces constructed by humans during the late Holocene, are thought to have improved the growing conditions fo...

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Main Authors: Amy S Groesbeck, Kirsten Rowell, Dana Lepofsky, Anne K Salomon
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3949788?pdf=render
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author Amy S Groesbeck
Kirsten Rowell
Dana Lepofsky
Anne K Salomon
author_facet Amy S Groesbeck
Kirsten Rowell
Dana Lepofsky
Anne K Salomon
author_sort Amy S Groesbeck
collection DOAJ
description Maintaining food production while sustaining productive ecosystems is among the central challenges of our time, yet, it has been for millennia. Ancient clam gardens, intertidal rock-walled terraces constructed by humans during the late Holocene, are thought to have improved the growing conditions for clams. We tested this hypothesis by comparing the beach slope, intertidal height, and biomass and density of bivalves at replicate clam garden and non-walled clam beaches in British Columbia, Canada. We also quantified the variation in growth and survival rates of littleneck clams (Leukoma staminea) we experimentally transplanted across these two beach types. We found that clam gardens had significantly shallower slopes than non-walled beaches and greater densities of L. staminea and Saxidomus giganteus, particularly at smaller size classes. Overall, clam gardens contained 4 times as many butter clams and over twice as many littleneck clams relative to non-walled beaches. As predicted, this relationship varied as a function of intertidal height, whereby clam density and biomass tended to be greater in clam gardens compared to non-walled beaches at relatively higher intertidal heights. Transplanted juvenile L. staminea grew 1.7 times faster and smaller size classes were more likely to survive in clam gardens than non-walled beaches, specifically at the top and bottom of beaches. Consequently, we provide strong evidence that ancient clam gardens likely increased clam productivity by altering the slope of soft-sediment beaches, expanding optimal intertidal clam habitat, thereby enhancing growing conditions for clams. These results reveal how ancient shellfish aquaculture practices may have supported food security strategies in the past and provide insight into tools for the conservation, management, and governance of intertidal seascapes today.
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spelling doaj.art-b9dafd4e75b24430be439f98ba6c21412022-12-22T00:34:32ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0193e9123510.1371/journal.pone.0091235Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.Amy S GroesbeckKirsten RowellDana LepofskyAnne K SalomonMaintaining food production while sustaining productive ecosystems is among the central challenges of our time, yet, it has been for millennia. Ancient clam gardens, intertidal rock-walled terraces constructed by humans during the late Holocene, are thought to have improved the growing conditions for clams. We tested this hypothesis by comparing the beach slope, intertidal height, and biomass and density of bivalves at replicate clam garden and non-walled clam beaches in British Columbia, Canada. We also quantified the variation in growth and survival rates of littleneck clams (Leukoma staminea) we experimentally transplanted across these two beach types. We found that clam gardens had significantly shallower slopes than non-walled beaches and greater densities of L. staminea and Saxidomus giganteus, particularly at smaller size classes. Overall, clam gardens contained 4 times as many butter clams and over twice as many littleneck clams relative to non-walled beaches. As predicted, this relationship varied as a function of intertidal height, whereby clam density and biomass tended to be greater in clam gardens compared to non-walled beaches at relatively higher intertidal heights. Transplanted juvenile L. staminea grew 1.7 times faster and smaller size classes were more likely to survive in clam gardens than non-walled beaches, specifically at the top and bottom of beaches. Consequently, we provide strong evidence that ancient clam gardens likely increased clam productivity by altering the slope of soft-sediment beaches, expanding optimal intertidal clam habitat, thereby enhancing growing conditions for clams. These results reveal how ancient shellfish aquaculture practices may have supported food security strategies in the past and provide insight into tools for the conservation, management, and governance of intertidal seascapes today.http://europepmc.org/articles/PMC3949788?pdf=render
spellingShingle Amy S Groesbeck
Kirsten Rowell
Dana Lepofsky
Anne K Salomon
Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.
PLoS ONE
title Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.
title_full Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.
title_fullStr Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.
title_full_unstemmed Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.
title_short Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.
title_sort ancient clam gardens increased shellfish production adaptive strategies from the past can inform food security today
url http://europepmc.org/articles/PMC3949788?pdf=render
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