East and west boundary fence plant line intercepts - percent cover for all species beginning 1986

BACKGROUND.
In the spring of 1982, as part of the establishment of
the Jornada Long-Term Ecological Research site in southern
New Mexico, a 135 ha portion of a 1500 ha, internally
drained, watershed was exclosed from grazing by domestic
livestock. Prior to exclosure the watershed, as well as the
rest of the Jornada basin, had been moderately to heavily
grazed for the past 100 years. Concurrent with grazing, the
vegetation had undergone a dramatic change from desert
grassland, with an almost continuous cover of C4 perennial
grasses, to isolated patches of the original grassland in a
mosaic with desert shrub dominated plant communities
(Buffington and Herbel, 1965).
The exclosure lies along a northeast facing piedmont
slope at the base of a steep isolated mountain peak, and
covers a variety of component landforms from the foot of the
mountain to the basin floor. This provided the opportunity
to investigate the response of vegetation with respect to
landscape characteristics as well as release from grazing.

This summary data set consists of percent cover of all perennial
plant species from the plant line intercept measurements on
either side of the LTER-I exclosure East and West boundary fence.
Data is sorted by treatment (grazed, ungrazed), year, fence line,
station, then species i.d. Along the East Boundary fence line,
the east side is ungrazed (control) and the west side is grazed
(treatment). Along the West Boundary fence line, the east side
is grazed and the west side is ungrazed. Each plant line
transect is divided into 6 5-meter segments. All perennials were
measured at about 5 year intervals as the length of intercept for
each species along a 30-meter line oriented perpendicular to the
fence. Summary data presented in this data set is the average
percent cover for the outer-most 2 5-meter segments for the
respective treatment (grazed or ungrazed). The term outer-most
is relative to the fence. The 5-meter segment on either side of
the fence is not included in the cover estimates due to fence
line effect disturbances; e.g., cattle trails, tumbleweeds
trapped along fence, etc.

This summary data does not include the first year of measurement
in 1982 because of numerous problems with species codes used that
could not resolved.