Part 1
TRANSECTS MADE
Transect 1 CT, CT, GM,
ST, B, RG, RG, WC, KB
Transect 2 BS,
BS, CT, CT, (NP), (NP), (NP), WC, GM, GM
Transect 3 KB,
CT, CT, S, S, (NP), (NP), (NP), CT, RG, BS, RG, KB, BM
CT-Canadian Thistle
(I)* B-Buckthorn (I) GM-Garlic Mustard (I)
WC-Wild Carrot
(N)** RG-Ryegrass (I) KB-Kentucky Bluegrass (I)
BS-Blazing Star
(N) S-Sedge (N) BM-Black Mustard (I) (NP)-(No Plant)
* Invasive ** Native
DIVERSITY
INDICES
Transect 1
DIG = 7/9
= 0.78 DIM= 1/7 = 0.14 DIE= (Square root) [0.78 x 0.14]
= 0.33
DIS = 6/7
= 0.86 DIO = (Cubed root) [0.78 x 0.14 x 0.86] = 0.45
Transect 2
DIG = 4/7
= 0.57 DIM= 2/4 = 0.5 DIE= (Square root) [0.57 x 0.5]
= 0.53
DIS = 4/4
= 1 DIO = (Cubed root) [0.57 x 0.5 x 1] = 0.66
Transect 3
DIG =
9/11 = 0.82 DIM= 2/9 =
0.22 DIE= (Square root)
[0.82 x 0.22] = 0.65
DIS = 6/9
= 0.67 DIO = (Cubed root) [0.82 x 0.22 x 0.67] = 0.49
Average DIO = (0.45 + 0.66 +
0.49)/3 = 0.53
The
overall diversity index (DIO) is a combination of the other formulas
and therefore reflect what they are trying to measure. It reflects the
diversity of plant species and how segregated or integrated they are as well as
how many of the species are native and how many are invasive to the area.
Taking three transects and coming up with an average ensures adequate coverage
of all different parts and features of the riverbank. The more transects that
are taken, the more accurately the final DIO represents how diverse
the area actually is in terms of autotrophs.
Our
final number, 0.53, is on a scale of zero to one. 0.53 tells us that the
riverbank is barely above what would be considered "average diversity". This
seems to be true because many of our plants are invasive. Invasive species tend
to disrupt the natural food webs and trophic pyramids in place, so it makes
sense that the health of the ecosystem as a whole would suffer because of many
invasive species. All in all, the riverbank autotrophs are extremely diverse,
its just that many of these species are invasive.
Part 2
The invasive species that was most successful was the dandelion (Taraxacum officinale.) There are several reasons why this was successful relative to the indigenous species. One reason was that the T. officinale's flowers bloom early. This reduces interspecific competition. Also, the T. officinale lives in areas where other plants don't. Specifically the T. officinale lives within eight feet of the path around the Slough. This also cuts drastically the competition level. The T. officinale adapts well to survive. We noticed a T. officinale less than two feet away from the riverbank. We compared this to another T. officinale, which lived near the path. Then the heights were compared. As was seen in the data part 3A, the average size for a T. officinale by the path was 11.1 cm, while the average size by the river was 27.5 cm. The dandelions by the river were over 2.5 times larger. This ability to adapt to get the necessary sunlight and wind to reproduce makes the T. officinale very successful.
The species of T. officinale likely entered the ecosystem by the spores of other T. officinale that were moved by the wind. The spreading of spores by the wind moved the spores to start and grow in another area. To combat the spread of the dandelion two things need to be done. One is a weed-killer would be very effective in killing a lot of the T. officinale before they reproduced. Also, like what is being done, mowing the grass along the path drastically affects the population sizes. This mowing significantly affects the life of the T. officinale. Without the constant watch of humans or a natural way to combat them, the slough will continue to have tens of thousands of dandelions.