Effect of Harding Grass Land Management on Native and Non-Native Plant Diversity in Coastal Grasslands

Meta-Data

Methods:

This experiment was performed at two grassland locations in
Cambria, California that were subject to two different management strategies.
At the first location, Rancho Marino Reserve, two different transects were set
up – one with no history of tilling or planting*(35.52895, -121.07758) and one
that had been previously tilled and planted (35.53932, -121.09002). At the
second location, Fiscalini Ranch Preserve, two transects were set up - both
with no history of tilling or planting (35.54976, -121.10072 and 35.5508,
-121.10195). All four transects were 100 meters long with 25 quadrats (0.5m x
0.5m) randomly placed along them. Plant community structure and composition
were assessed in one census per transect over a three-day period. We observed
abundance through species diversity, percent coverage, density, and flower
count. Species diversity was measured through direct count of the number of
different species found in each quadrat. Percent coverage was assessed visually
and flower count was counted directly. The density was calculated by counting
the number of individual plant stems in four circular rings (20.27 cm2) placed
in the center of each quarter of the quadrat and then dividing by the total
surface area of the rings (81.07cm2). These measurements were taken separately
for Phalaris aquatica, native species, and non-native species.
Co-variants and soil moisture levels were also considered to control for any
confounding variables.

*“Planting” refers to the intentional introduction of Phalaris
aquatica

Data:

The column site has two values: RM refers to Rancho Marino
Reserve and FR refers to Fiscalini Ranch Preserve. Management indicates the
historical management strategies of both sites and whether there was an
introduction of Phalaris aquatica (Harding grass). Each
location has two sampling sites on 100-meter-long transects and the column
rep.day refers to the quadrat sample number at each transect. Harding cover,
exotic plant cover, and bare cover refer to the percentage of ground covered by
each. Animal sign indicates any animal presence found within the quadrats
including scat, holes, trails, and/or individuals. Abundance is a calculation
derived by adding the diversity value for Harding grass, exotic plants and
native plants. Diversity is a count of all different species of plant present
in each quadrat. Sampling time and rate per hour are irrelevant to this
experiment. Harding density, native density, and exotic density refer to the
number of relevant individuals that occur in the quadrat. The density value was
calculated by adding the number of individual plant stems in four surface area
samples and dividing the resulting value by the total surface area sampled.
This value was then multiplied by 100 to extrapolate for the entire quadrat.
Native flowers and exotic flowers is a direct count of the number of flowers
found within the quadrat. Soil moisture is a measure of the water content of
the soil in the quadrat taken with a digital soil moisture meter - all results
indicated the soil was “too dry.”

**Authors are all equal contributors listed in alphabetical
order.