A study of the abundance of species in grassland-to-pond transition zone and impermeable ground habitats

Hypothesis:
The distribution of species is dependent on how well the niche can
provide for the behavioural, physiological, and adaptive needs of the species.
A niche that can provide a variety and multitude of resources can support a
larger abundance of species than niches who provide minimal resources. Every
species has its own particular set of needs, but higher trophic organisms like
vertebrates need more resources than lower trophic level organisms like
invertebrates. If the habitat has limited resources, it will most likely have
fewer vertebrates since it cannot meet the higher needs of the vertebrates.
Predictions:
1) In areas with a greater abundance of woody plants there is less
ground cover as the woody plants cover the ground with shade reducing the
amount of sunlight that ground covering plants can acquire, preventing growth.
2) There will be a greater abundance of invertebrates within the
transition area because of both the high canopy and ground coverage which
offers protection from the sun and predators, and the greater availability of
food (plants).
3) There will be a greater abundance of vertebrates within the
transition area due to the higher availability of invertebrates and plants as a
food source.
Location
Data was collected at York University on the Keele campus at two
study sites; a transition habitat(wetland/grassland) near a pond and on a
baseball field with an impermeable surface. GPS location for the transition
area and baseball field was 43.7706, -79.5066 and 43.7682, -79.5073
respectively. Elevation for the transition area and baseball field was 151.74m
and 137.746m respectively. Outside this transition area were well-circulated
paths, and picnic areas were found within the area itself. There was a pond
nearby with a group of 5 waterfowls. The sampled area was inclined along the
edge of the pond. The baseball field was paved over with fine dirt and pebbles.
Here, there were many circulated roads and signs of other human activities. The
baseball field was a newer area. The weather was sunny with temperatures
reaching 22C and humidity reaching 60%, and windspeeds reaching 8km/hr.
Meta-data
Travelled to a transition area(wetland/grassland) and a baseball
field with an impermeable soil at York University Keele campus to collect four
datasets (43.7706, -79.5066 and 43.7682, -79.5073 respectively). This data was
collected by visual counting from transects, 1m x 1m quadrats, sweep nets, and
pan traps. For the first data set, (measured abundance of native plants,
abundance of exotic plants and total number of flowers), the transition area
was first sampled. A 50m transect was drawn parallel, along the edge of the
pond. Every two metres a quadrat was placed on alternating sides of transect.
The number of individuals of native and exotic plant species were counted
within the quadrat. All grasses were considered to be exotic and all other
plants considered to be native. Next, the total number of observed flower heads
within the quadrat; all levels of inflorescence were considered flower heads
(i.e. buds and blossoming). This method was replicated for the baseball field
except the placement of the transect wasn’t specially placed since the area was
relatively homogenous (i.e. flat, impermeable soil). In both areas, a total of
25 quadrats replicates were done. For the second dataset (measuring abundance
of woody plants, canopy cover, ground cover, and total number of flowers) in
the transition area, a 50m transect was drawn along the edge of the pond. Trees
were counted every two meters within 0.5 m of the transect. Only trees larger
than 1.5 meters in height were counted. Having a height requirement decreased
the probability of counting a non-woody plant. Also, every two metres, the
vegetative ground cover and canopy cover was approximated in percent. The area
was visually divided into quadrats, then the area covered was estimated as a
percentage. Total number of flowers were counted using quadrats as well. This
method was repeated for the baseball field;random placement of transect. In
both areas, 25 replications were done. For the third dataset (measuring
abundance of vertebrates, abundance of invertebrates observed and abundance of
humans), the transition area was first sampled. Point survey was conducted by a
50m transect and observing the 50m radius area from the beginning of the
transect. The total number of invertebrates were counted (ie. insects and
mollusks). Then in 15 minutes, all humans not part of the study group were
counted to survey pedestrian circulation. This was to check for the level of
human disturbance in normal conditions. Then in another 15 minutes, the number
of invertebrates were counted within a 5 meter radius. This radius was chosen
along the transect with the least disturbance, in particular human disturbance.
This method was replicated for the baseball field; random placement of
transect. In both areas, the point surveys were repeated once (for an n of 2).
For the fourth dataset (measuring abundance of invertebrates in trap pans,
abundance of invertebrates caught in sweep nets, and abundance of invertebrates
observed within a specific time), the transition area, 6 pan traps (blue,
white, yellow) were placed 3 meters apart while alternating colors. Pans were
placed by the edge of the pond. The pan trap was left for 45 minutes and then
the number of invertebrates caught were counted. Then, along 50m by the edge of
the pond, sweep nets were used to catch any invertebrates (flying or crawling).
Nets were swept upward and left to right motion on the grass and tall plants.
This method was repeated for the baseball field. In the baseball field, sweep
nets were hung very low to the ground as there was little to no vegetation
(only single plants; weeds, grass bunches at the edges of the field). For both
areas, the pan traps were placed once and the sweep nets conducted 10 times.
Methods:
30m transects were run (north to south) parallel to the pond and
quadrat samples were taken on both sides of the transect every 2m (n = 25). To
count the abundance of native and exotic herbaceous plants, surveyors used a
1.00m x 1.00m quadrat to visually inspect and sample individuals. Sampling was
conducted by the surveyor counting the abundance of native and exotic
herbaceous plants per the bottom-left quarter of the quadrat, the sampling was
then multiplied by a factor of 4 to gain total abundance. Total number of
flowers were counted and inspected by the surveyor (inflorescences were counted
as individual flower units). In the impermeable ground habitat the transect was
run for 30m and samples were taken the same as described above.
For woody plants, a 30m transect was extended parallel to the pond
and for every 2m a surveyor observed for woody plants (defined as those plants
greater than a height of 1.5m) within 0.5m of the transect (n = 25). At these
points canopy and ground coverage was estimated via surveyor’s visual
inspection, by visualizing quadrats above and below the surveyor. As well,
total flower numbers were recorded similarly as described above.
Point surveys were conducted for periods of 15 minutes (n = 2) for
the abundance of vertebrates, diversity of species, abundance of invertebrates,
and abundance of humans. The survey involved running a transect for 50m
(parallel to the pond) and a surveyor visually inspecting and counting for the
above listed species in an area within a 50m radius of the transect start
point. Point survey was conducted on the impermeable ground as described
previously.
Parallel to the pond, pan traps were set 3 meters(paces) apart
while alternating colours (Yellow, blue, white) along the length of a transect
(30 meters). Each pan trap was one replicate (total of n=6) and the total
number of invertebrates within the pan trap were counted and recorded. Then,
sweep nets were conducted next to the 50 meter transect. Each sweep was one
replicate (for a total of n=10) and the total number of invertebrates found at
the end of the sweep were counted and recorded. Pan traps and sweep nets were
set and conducted as described for the impermeable ground as well.
Variables
Abundance of native plants – The visual inspection and count of
native plant species (primarily flowering species) per a 1.0m x 1.0m quadrat.
Numerical, discrete.
Abundance of exotic plants – The visual inspection and count of
exotic plant species (primarily grass species) per a 1.0m x 1.0m quadrat.
Numerical, discrete.
Total number of flowers – The visual inspection and count of
flowers (inflorescences were counted as single units) per a 1.0m x 1.0m
quadrat. Numerical, discrete.
Abundance of woody plants – The visual inspection and count of
woody plants (taller than 1.5m). Numerical, discrete.
Canopy cover – The visual estimation of the percent area covered
by the canopy of the woody plants. Numerical, continuous.
Ground cover - The visual estimation of the percent area covered
by the herbaceous plants on the ground. Numerical, continuous.
Abundance of vertebrates – The visual inspection and count of
vertebrate species in the radius of the point survey. Numerical, discrete.
Vertebrate species – The visual inspection and count of the
diversity of vertebrate species within the radius of the point survey.
Numerical, discrete.
Abundance of invertebrates – The visual inspection and count of
invertebrate species in the radius of the point survey. Numerical, discrete.
Abundance of invertebrates pan traps – The visual inspection and
count of invertebrates caught in pan traps during a 45 minute period.
Numerical, discrete.
Abundance of invertebrates sweeps – The visual inspection and
count of invertebrates caught in sweep nets over a 50m transect. Numerical,
discrete.