Supplement 1. The data sets analyzed in this paper.

File List

Data_files.zip
-- zip file containing the four tab-separated ASCII data files listed below.

Primary_dataset.txt
-- the complete data set used in analyses and presented in Table 1 and Fig.
2 of the article.

Ordination_data.txt
-- data used to ordinate the 473 streams in Fig. 1.

Species_densities.txt
-- a site × species matrix of periphyton densities on sampling
tiles (precursor to estimating rates of biomass accrual).

Species_productivities.txt
-- a site × species matrix of periphyton productivities (rate
of biomass accrual) on the sampling tiles.

Description
The file Data_files.zip
contains four tab-separated ASCII data files. Each of these four files
is described in detail below:

File 1 = Primary_dataset.txt
-- the summarized dataset used in analyses and presented in Table 1 and Fig.
2. Variables by column are:

1 = U.S. Geological
Survey (USGS) stream gauging station.

2 = Description of
gauging station location.

3 = USGS Hydrologic
Unit Code (HUC).

4 = Latitude of gauging
station (degrees).

5 = Longitude of gauging
station (degrees).

6 = The Environmental
Protection Agency's Type III ecoregion (see reference to Omerik and Griffith
1991 in paper). These denote different shaded areas in Fig. 1B of our
paper.

7 = Categorical grouping
of naturally occurring stream "clusters" where one or more streams
in each study group were located within a 48-km radius in the same ecoregion. These
denote polygons in Fig. 1B of our paper.

8 = The coefficient
of variation of mean daily stream discharge (Q) from 1 October 1989 to 30
September 1999.

9 = The temporal predictability
of mean daily discharge, calculated as Colwell's index (see reference to
Colwell 1974 in paper)

10 = The coefficient
of variation of mean monthly stream discharge (Q) from 1 October 1989 to
30 September 1999.

11 = The temporal
predictability of mean monthly discharge, calculated as Colwell's index
(see reference to Colwell 1974 in paper)

12 = The mean number
of floods per year, with a flood defined as any Q exceeding the 1.67 year
recurrence interval.

13 = The temporal
predictability of floods, calculated as Colwell's index (see reference to
Colwell 1974 in paper)

14 = Factor scores
from PC1 used to ordinate streams in Fig. 1A.

15 = Factor scores
from PC2 used to ordinate streams in Fig. 1A.

16 = The study group
is the stream disturbance category determined from the ordination of streams
by PC1 and PC2 (see Fig. 1A). LD stands for relatively low disturbance
streams while HD stands for relatively high disturbance streams.

17 = Day of water
year on which periphyton were collected from sampling tiles. Note that
the USGS water year begins on 1-October.

18 = The number of
days that tiles were incubated in the stream prior to sampling.

19 = Periphyton species
richness on sampling tiles, which includes all taxa of Bacillariophyceae,
Cyanobacteria, Chlorophyceae, Euglenophyceae, and Pyrrophyta.

20 = Net production
of periphyton, taken to be the rate of biomass accumulation on the sampling
tiles (micrograms cm2/d) .

21 = The expected
productivity of the periphyton assemblage (micrograms cm2/d)
determined from the median regional productivity of each taxon (see Eq.
2 in text).

22 = Percent canopy
cover above each sampling tile meaured with a densiometer and spatially
averaged for the six tiles taken from the stream.

23 = Width of the
wetted stream channel (in meters).

24 = Conductivity
(microS/cm) of a single stream water sample measured with an Orion QuikChek
probe.

25 = Stream drainage
area (km2), as reported on the USGS NWISWeb.

26 = Mean invertebrate
herbivore biomass (g/m2) in three replicate
900-cm2 Surber samples taken from the
same stream riffles in which periphyton sampling tiles were placed.

27 = Watershed export
of Total Nitrogen (kg/d) predicted for the hydrologic unit code (HUC) based
on the SPARROW modeling program of the USGS (see references to Alexander
et al. 1998 and 2004 in text).

28 = Watershed export
of Total Phosphorus (kg/d) predicted for the hydrologic unit code (HUC)
based on the SPARROW modeling program of the USGS (see references to Alexander
et al. 1998 and 2004 in text).

29 = pH of a single
stream water sample

30 = Mean water depth
(cm) measured directly above the replicate sampling tiles.

31 = Stream water
temperature, in degrees Celsius

32 = Water velocity
(m/s) measured 3–5 mm above each sampling tile using a Valeport 8005/801
electromagnetic probe. Velocity is the mean of a 25-s time series with
data spatially averaged across the replicate tiles collected.

33 = Turbulence, taken
to be the standard deviation of velocity for the 25-sec time series.

Cells with missing values are
delimited by "."

To verify that the file has
downloaded properly, column sums and the number of cells with "." can be
compared to the following:

-- TABLE: Please see in attached file. --
n/a = not applicable, column
is text.

File 2 = Ordination_data.txt
-- contains data used to ordinate the 473 streams displayed in Fig. 1. Variables
by column are:

1 = U.S. Geological
Survey (USGS) stream gauging station.

2 = Description of
gauging station location.

3 = Latitude of gauging
station (degrees).

4 = Longitude of gauging
station (degrees).

5 = The coefficient
of variation of mean daily stream discharge (Q) from 1 October 1989 to 30
September 1999.

6 = The temporal predictability
of mean daily discharge, calculated as Colwell's index (see reference to
Colwell 1974 in paper)

7 = The coefficient
of variation of mean monthly stream discharge (Q) from 1 October 1989 to
30 September 1999.

8 = The temporal predictability
of mean monthly discharge, calculated as Colwell's index (see reference
to Colwell 1974 in paper)

9 = The mean number
of floods per year, with a flood defined as any Q exceeding the 1.67 year
recurrence interval.

10 = The temporal
predictability of floods, calculated as Colwell's index (see reference to
Colwell 1974 in paper)

11 = Factor scores
from PC1 used to ordinate streams in Fig. 1A.

12 = Factor scores
from PC2 used to ordinate streams in Fig. 1A.

To verify that the file has
downloaded properly, column sums can be compared to the following:

-- TABLE: Please see in attached file. --
n/a = not applicable,
column is text.

File 3 = Species_densities.txt
-- a site (rows) by species (columns) matrix of periphyton densities on the
sampling tiles (number of individual cells per square cm). Each column
has the species ID as the header, with that ID followed by a D = diatom
(Bacillariophyceae), CY = Cyanobacteria, CH = Chlorophyceae
, EU = Euglenophyceae, or PY = Pyrrophyta.

Cells with a "." indicate the
taxon was not found on sampling tiles placed in that site. 

To verify that the file has downloaded
properly, column sums and the number of cells with "." can be compared to
the following:

-- TABLE: Please see in attached file. --

n/a = not applicable, column
is text.

File 4 = Species_productivities.txt
-- a site (rows) by species (columns) matrix of periphyton productivities
on the sampling tiles (micrograms of biomass accrual cm2/
d). Each column has the species ID as the header, with that ID followed
by a D = diatom (Bacillariophyceae), CY = Cyanobacteria, CH = Chlorophyceae
, EU = Euglenophyceae, or PY = Pyrrophyta.

...