Experimental design
In 2004 five temporary fences were constructed along the permanent
fence, extending approximately 6 m into the summer (heavily) grazed side
of the fence, before reindeer entered the area in the autumn. Each of
the temporary fences is between 85 and 185 meters in length and built in
areas that allowed for the capturing of terrain and elevational
differences. The temporary fences were taken down every other year to
allow for grazing in the area closest to the permanent fence every
second year (Figure 1a). The area on the inside of the temporary fence
was thus exposed to acute (i.e. pulse grazing) after more than forty
years of chronic (i.e. press grazing), while the areas outside of the
temporary fence continued to experience press grazing. We placed
permanent plots in the sites along the permanent fence where the
temporary fences were constructed (n = 5 sites). Each site contained two
sets of triplets (n = 6 plots) except for the fourth fence, which
contained four sets of triplets (n = 12 plots), for a total of 36
permanent plots (Figure 1b). At each site, one set of triplets was
placed in a drier area (18 plots in total) and the other in a moist/wet
area (18 plots in total); we refer to this covariate as wet/dry. Within
each triplet, each of the three plots was exposed to a different grazing
intensity: the plot on the side of the permanent fence in the spring and
autumn ranges was lightly grazed (12 plots in total), the plot inside
the temporary fence was grazed every other year (pulse grazing; 12 plots
in total), and the plot on the side of the permanent fence in the summer
grazed area was grazed every year (press grazing; 12 plots in total).
All plots were placed no more than 12m from the permanent fence, but
plots on the lightly grazed side of the fence were placed 3m away from
the fence due to the man-made disturbance in this area from herders
walking next to the fence. Each plot was 3m x 3m (9m2)
and was evenly split into nine 1m x 1m (1m2)
sub-plots.