The influence of land use on the nearshore pelagic foodweb
Presentation Abstract
In the oceanographically diverse and urbanized fjord estuary we know as greater Puget Sound, our scientific understanding of pelagic ecology is poor, and systematic monitoring and assessment of living systems has long been neglected. Improved understanding of biological responses to our human footprint is needed to predict the response of the pelagic ecosystem to human actions. In this talk, we examine existing spatial and seasonal patterns of Puget Sound’s nearshore pelagic foodwebs measured along natural and anthropogenic gradients. We tested whether abiotic and biotic metrics were sensitive to land use activities (urbanization and agriculture) in the catchments surrounding sampling sites in nearshore pelagic waters. To address this question, we conducted a large survey effort (monthly sampling of 79 sites from April to October) in 2011 examining multiple foodweb components in nearshore surface waters of six oceanographic sub-basins of Puget Sound. We observed strong spatial and seasonal structure in a suite of abiotic variables (e.g., temperature, dissolved oxygen, pH, inorganic nutrients) and biological attributes (e.g., bacterial production, chlorophyll a concentrations, zooplankton density, catch of fish and jellyfish). Despite this large-scale variation, many metrics nevertheless exhibited associations with local measures of land use, although these associations were often subtle (< 10% of the observed variation) and variable across basins. The general pattern was that abiotic and lower trophic attributes were more sensitive and fish abundance and diversity were less sensitive. These findings suggest that current management practices that assume uniform conditions across Puget Sound and that ignore the cumulative effects of land use actions are unlikely to adequately redress human impacts on pelagic ecosystems.
Session Title
Session S-01D: Pelagic Ecology in the Salish Sea I
Conference Track
Species and Food Webs
Conference Name
Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)
Document Type
Event
Start Date
30-4-2014 10:30 AM
End Date
30-4-2014 12:00 PM
Location
Room 611-612
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Food chains (Ecology)--Salish Sea (B.C. and Wash.); Marine ecology--Salish Sea (B.C. and Wash.); Land use--Environmental aspects--Salish Sea (B.C. and Wash.)
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
The influence of land use on the nearshore pelagic foodweb
Room 611-612
In the oceanographically diverse and urbanized fjord estuary we know as greater Puget Sound, our scientific understanding of pelagic ecology is poor, and systematic monitoring and assessment of living systems has long been neglected. Improved understanding of biological responses to our human footprint is needed to predict the response of the pelagic ecosystem to human actions. In this talk, we examine existing spatial and seasonal patterns of Puget Sound’s nearshore pelagic foodwebs measured along natural and anthropogenic gradients. We tested whether abiotic and biotic metrics were sensitive to land use activities (urbanization and agriculture) in the catchments surrounding sampling sites in nearshore pelagic waters. To address this question, we conducted a large survey effort (monthly sampling of 79 sites from April to October) in 2011 examining multiple foodweb components in nearshore surface waters of six oceanographic sub-basins of Puget Sound. We observed strong spatial and seasonal structure in a suite of abiotic variables (e.g., temperature, dissolved oxygen, pH, inorganic nutrients) and biological attributes (e.g., bacterial production, chlorophyll a concentrations, zooplankton density, catch of fish and jellyfish). Despite this large-scale variation, many metrics nevertheless exhibited associations with local measures of land use, although these associations were often subtle (< 10% of the observed variation) and variable across basins. The general pattern was that abiotic and lower trophic attributes were more sensitive and fish abundance and diversity were less sensitive. These findings suggest that current management practices that assume uniform conditions across Puget Sound and that ignore the cumulative effects of land use actions are unlikely to adequately redress human impacts on pelagic ecosystems.
