Online Resource 1
Article Title: Multiple scales of influence on wetland vegetation associated with headwater streams in Alaska, USA
Journal: Wetlands
Author names: Dennis F. Whigham, Coowe M. Walker, Ryan S. King, Steven J. Baird
Author affiliations: Whigham: Smithsonian Environmental Research Center, P.O. BOX 28, 647 Contees Wharf Road, Edgewater, Maryland 21037-0028 USA
Walker and Baird: Kachemak Bay Research Reserve, 95 Sterling Highway, Suite 2, Homer, AK 99603 USA
King: Center for Reservoir and Aquatic Systems Research, Department of Biology, Baylor University,One Bear Place 97388, Waco, Texas 76798-7388 USA
Author for correspondence: Whigham. Email:
Online Resource 1. List and description of plot-, watershed- and stream-level variables used as environmental arrays in the ordination analysis of vegetation data. Detailed descriptions of methods for obtaining data for each variable are provided in Walker et al. (2012) and King et al. (2012). Abbreviations for the variables that were significantly related to the ordination axes are listed in the legend for Fig. 2.
Plot-scale variables
% of plot mapped as wetland / Wet %
% of plot mapped as upland / Uplant %
% of the plot mapped as open water or emergent vegetation / Water %
Wetland type, based on the classification and mapping by Gracz et al. (2008) / Wettyp
Live tree density / Live T
Standing dead tree density / Dead T
Density of downed trees / Down T
Shrub importance values / Shrub
Watershed-level variables
Elevation of the study plot / Elev.m
Topographic wetland index / Wetx
Flow-weighted slope / FWSlope
Mean slope of the watershed / Wslope
Total wetland cover / Wet %
% of watershed with discharge slope wetlands / DS
% of watershed with drainage ay wetlands / DW
% of watershed with lakebed wetlands / LB
% of watershed with kettle wetlands / KT
% of the watershed in riparian wetlands / RP
Watershed size / Shed KM2
Stream-level variables
Substrate - fines / Fines
Substrate – silt / Silt
Substrate – sand / Sand
Substrate – peat / Peat
Substrate – small gravel / Grav.sm
Substrate – large gravel / Grav.lg
Substrate – cobble / Cobb
Substrate – small boulders / Bould.sm
Substrate – large boulders / Bould.lg
Bottom characteristic – embedded / Embed
Presence of periphyton / Peri
Presence of roots / Roots
Presence of small woody debris / SWD
Presence of large woody debris / LWD
Presence of overhanging vegetation / Overveg
Density of overhead canopy / Canopy
Stream width / Width
Bank height / Bk.ht
Thalweg depth / Thalweg
Stream cross section water depth / Depth.xs
pH of stream water / pH
Dissolved oxygen (mg/l) in stream water / DO.mgl