Connectivity Modifier (Conmod) Pilot methods
For the data table in this data package, canopy and basal gap sizes
between vegetation were measured using the gap 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 gap 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 gap 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, vegetation cover at the
canopy and basal, or ground, levels were measured using the gap
intercept method. Canopy and basal transects are denoted as C and B
types in the data table, respectively. Gaps along each transect are
recorded with their start point, end point, and total size in
centimeters (end - start). Gaps smaller than 20cm in length were
ignored. These measurements were made annually during the summer in
2008-2010, and again in 2012 and 2016.
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 gap 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).
