Broad-Scale Environmental Predictors of Intertidal Zonation of Z. japonica and Z. marina
Presentation Abstract
Physical and biotic factors can influence the distribution of species at multiple scales, and are thus important when predicting invasive species impacts. I examined the influence of physical context and congener presence on variability the vertical zonation of an invasive seagrass, Z. japonica and its native congener Z. marina. Nearshore intertidal topography, hydrodynamic exposure, and tidal range were examined as abiotic predictors of the deep extents of Z. japonica and Z. marina, the shallow extent of Z. marina and the elevation overlap of the two species, both at within site and among site spatial scales. Z. marina’s extended to higher elevations at transects that were less rough, more gently-sloped, less wave exposed, and in the presence of Z. japonica. Site-scale rugosity was the best predictor of site scale shallow extent of Z. marina. Z. japonica deep extent was explained by Z. marina shallow extent at both spatial scales, and also by rugosity when examining site-averaged patterns. Overlap of the two species along a transect was poorly predicted by physical context, but site-averaged range overlap was greater where depth profiles were more linear. Bottom profile complexity was the most consistently important predictor studied, confirming the importance of the geomorphic template on the zonation of these species. Furthermore, these findings suggest a greater sensitivity of Z. marina shallow extent to physical factors, and a greater sensitivity of Z. japonica deep extent to biotic factors.
Session Title
Session S-07E: Aquatic Vegetation
Conference Track
Habitat
Conference Name
Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)
Document Type
Event
Start Date
1-5-2014 5:00 PM
End Date
1-5-2014 6:30 PM
Location
Room 6C
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)
Dwarf eelgrass--Growth--Salish Sea (B.C. and Wash.); Zostera marina--Growth--Salish Sea (B.C. and Wash.); Invasive plants--Salish Sea (B.C. and Wash.); Plant competition--Salish Sea (B.C. and Wash.); Intertidal zonation--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
Broad-Scale Environmental Predictors of Intertidal Zonation of Z. japonica and Z. marina
Room 6C
Physical and biotic factors can influence the distribution of species at multiple scales, and are thus important when predicting invasive species impacts. I examined the influence of physical context and congener presence on variability the vertical zonation of an invasive seagrass, Z. japonica and its native congener Z. marina. Nearshore intertidal topography, hydrodynamic exposure, and tidal range were examined as abiotic predictors of the deep extents of Z. japonica and Z. marina, the shallow extent of Z. marina and the elevation overlap of the two species, both at within site and among site spatial scales. Z. marina’s extended to higher elevations at transects that were less rough, more gently-sloped, less wave exposed, and in the presence of Z. japonica. Site-scale rugosity was the best predictor of site scale shallow extent of Z. marina. Z. japonica deep extent was explained by Z. marina shallow extent at both spatial scales, and also by rugosity when examining site-averaged patterns. Overlap of the two species along a transect was poorly predicted by physical context, but site-averaged range overlap was greater where depth profiles were more linear. Bottom profile complexity was the most consistently important predictor studied, confirming the importance of the geomorphic template on the zonation of these species. Furthermore, these findings suggest a greater sensitivity of Z. marina shallow extent to physical factors, and a greater sensitivity of Z. japonica deep extent to biotic factors.
