Connectivity Modifier (Conmod) Pilot methods
For the data table in this data package, vegetation cover, species,
and height were measured using the line-point intercept method
described by Herrick et al. (2005). Archived and updated versions of
this document are available at
https://www.landscapetoolbox.org/manuals/ . Observations impacting
the quality of these measurements are recorded in the history file.
A schematic of how the line-point intercept transects were arranged
with respect to the study plots is also included in the data
package. Both of these documents are listed in the "Additional
documents" section below)
Basic Study Set Up and Location
There are 3 sites for the Conmod Pilot study: Gravelly Ridges,
Aeolian, and Dona Ana (referred to as G, A, and D, respectively).
Within each site, there are 8 plots. The plots are 8 x 8 meters and
have an 8 x 8 meter buffer zone on both sides of the plot (upwind
and downwind). At each site, 4 of the 8 plots are treatment plots
where connectivity modules (conmods) have been installed to decrease
the gap size between perennial vegetation. The other 4 plots are
untreated controls. Buffer zones do not have conmods installed.
Four parallel line-point intercept transects (numbered 1-4) were
established at each plot in 2008. These transects were laid out
across the upwind buffer (8 m), the plot (8 m), and the downwind
buffer (8 m) for a total distance of 24 meters each. The 4 parallel
transects were spaced evenly across each plot at 0.8, 2.8, 4.3, and
7.2 meter intervals. Along each transect intercept points were
arranged at 25 cm intervals and cover was measured at each point by
dropping a pinflag and observing woody and herbaceous vegetation
that intercepted this pin. For each point, a top level intercept and
up to 4 lower level intercepts were observed. The species or cover
type (plant id, conmod, etc.) of the top and first lower level
intercepts (if present) were recorded. If possible, the height of
these two intercepts was measured using the disc method. Only
species/cover type was recorded for below the first lower level
intercept (Lower2-4). The cover type (plant, soil, conmod, etc.) at
the soil surface at the bottom of each pin was also recorded. In
2016 the measurement method changed so that woody and herbaceous
plants were recorded separately at each point. Species identity (or
cover type) and height of the largest woody AND herbaceous plants
within 15 cm of each transect point was recorded that year.
Measurements for this data package were made annually during the
summer in 2008-2010, and again in 2012 and 2016.
IMPORTANT NOTES
NOTE 1: Plant species codes in the
"TopCanopy", "Lower1",
"Lower2","Lower3", "Lower4",
"SpeciesWoody", and "SpeciesHerbaceous" columns
of the data file generally correspond to USDA Plants Database codes
(plants.usda.gov). However, there are a number of codes specific to
data collection in this study. The included
"ConMod_covercode_key.csv" file contains explanations of
all cover codes. Further details about recognized taxa may be found
in the "JRN Vascular Plants" EDI package
(knb-lter-jrn.210520001).
Treatment plots by site
Aeolian site: 1,3,6,7 (Control plots are 2,4,5,8)
Dona Ana site: 1,3,6,8 (Control plots are 2,4,5,7)
Gravelly Ridges site: 2,4,6,8 (Control plots are 1,3,5,7)
Additional documents
A schematic of the line-point intercept transects (though only 3 are
shown) are found in
"Connectivity_Study_Design_Schematic.pdf"
Historical and contextual notes about data collection (and the
"comments" column) are found in the file
"Connectivity-pilot_his.txt"
References
Herrick, J. E., J. W. Van Zee, K. M. Havstad, L. M. Burkett, and W.
G. Whitford. "Monitoring manual for grassland, shrubland and
savanna ecosystems, Volume I." US Department of
Agriculture-Agriculture Research Service, Jornada Experimental
Range, Las Cruces, New Mexico (2005).
