Monday, May 27, 2013
Detailed Site Description
In my field site, the majority of my
area is covered in brush. I estimate a
total of 75% of the marshland is covered with common vegetation, such as
pickleweed (35%), cord grass (25%), and salt grass (15%). Approximately 7% of my area is covered by the
two coyote bushes. My area contains no
trees and only a small portion has a small rivulet at its edge (constituting
about 3%). The only man-made structure
is found at the edge of my study site where wooden posts are stuck in the
ground (making up about 5%). The
remainder of my site (10%) is merely bare ground.
Though I did not see many animals there were several rather prominent signs that they were living in my site area. The first sign I noticed was scat. Littered across the ground was a scattering of small round pellets. They appear to belong to a rabbit, possibly jack rabbit. This would make sense since I had discovered a hole underneath some pickleweed and cord grass on a previous visit. In addition, I found an empty mussel shell among the pickleweed. The shell was still intact, however, since it was empty, I can assume that some sort of organism had eaten it. The most likely predator is a seabird, probably a duck, goose, or seagull. Finally, I found a crushed snail shell along with a cracked egg shell. The snail was probably eaten by a goose or seagull. The crushed egg shell indicates either an extremely old hatched egg or that an organism had eaten the egg and the baby bird within. I suspect the latter mostly because the egg shell was relatively clean.
For the most part the soil is relatively muddy. While there is a sandy quality to it, the soil is damp because it is near a water source. The soil is likely home to many detritus organisms. Since it has a high content of water, it has a high carrying capacity for detritivores, who require soil with plenty of water to convert the decaying matter into viable nutrients. As a result there are copious amounts of pickleweed, cord grass and salt grass since they have access to a larger amount of nutrients. Since there are more plants, there is a higher rate of primary productivity, which will, therefore, be able to sustain a greater number of organisms. This is one of the reasons that the marshland has such a high diversity and abundance of waterfowl.
Since this area of the marsh is located at a point at which freshwater meets saltwater, it is considered an estuary. The estuary causes the surrounding soil to be moist and damp, perfect for detritivores. There will be a larger number of plants surrounding the rivulet because the organisms living in the detritus, such as beetles, mites, and worms, all contribute to the nutrients within the soil. The water will be home to organisms that have adapted to the varying salt concentrations of the water. Since the tide seasonally flows and recedes, organisms must have specific adaptations, such as gills, to absorb freshwater without intaking excessive amounts of salt. As the water is composed of both fresh and salt water, certain regions of it may be drinkable for waterfowl and other organisms, for instance, rabbits and foxes.
The area is completely flat up until the last couple meters where it dips down to enter the water source. The incline provides a perfect area for digging burrows. If well hidden behind a group of pickleweed or cord grass vegetation, as the burrow I found was, it would provide plenty of shelter from predators, such as foxes, if they weren't paying enough attention. In addition, the incline would also allow water to easily runoff into the rivulet. Any organisms living within the rivulet, including any shrimp, clam, and flounder, would then have a larger habitat. They would be more likely to survive in a bigger area and produce more offspring. The great amount of these secondary consumers will in turn contribute to a higher number of secondary consumers, such as ducks, geese, and seagulls, and also tertiary consumers, such as foxes.
The climate has been generally temperate thus far. Temperatures range from 68-70 degrees Fahrenheit on each of the three visits. The sky has been a clear blue up until the last visit where it was partly cloudy. It is only recently that it has rained at all. The rain provides optimal conditions for detritus organisms. The detritivores likely thrive in winter and spring when rainfall is heaviest. During the summer, the dry climate and warmer temperatures would decrease the population of these detritivores, thus, leading to a decrease in primary productivity and available nutrients. There would likely be more intraspecific as well as interspecific competition between vegetation in addition to waterfowl.
Though I did not see many animals there were several rather prominent signs that they were living in my site area. The first sign I noticed was scat. Littered across the ground was a scattering of small round pellets. They appear to belong to a rabbit, possibly jack rabbit. This would make sense since I had discovered a hole underneath some pickleweed and cord grass on a previous visit. In addition, I found an empty mussel shell among the pickleweed. The shell was still intact, however, since it was empty, I can assume that some sort of organism had eaten it. The most likely predator is a seabird, probably a duck, goose, or seagull. Finally, I found a crushed snail shell along with a cracked egg shell. The snail was probably eaten by a goose or seagull. The crushed egg shell indicates either an extremely old hatched egg or that an organism had eaten the egg and the baby bird within. I suspect the latter mostly because the egg shell was relatively clean.
For the most part the soil is relatively muddy. While there is a sandy quality to it, the soil is damp because it is near a water source. The soil is likely home to many detritus organisms. Since it has a high content of water, it has a high carrying capacity for detritivores, who require soil with plenty of water to convert the decaying matter into viable nutrients. As a result there are copious amounts of pickleweed, cord grass and salt grass since they have access to a larger amount of nutrients. Since there are more plants, there is a higher rate of primary productivity, which will, therefore, be able to sustain a greater number of organisms. This is one of the reasons that the marshland has such a high diversity and abundance of waterfowl.
Since this area of the marsh is located at a point at which freshwater meets saltwater, it is considered an estuary. The estuary causes the surrounding soil to be moist and damp, perfect for detritivores. There will be a larger number of plants surrounding the rivulet because the organisms living in the detritus, such as beetles, mites, and worms, all contribute to the nutrients within the soil. The water will be home to organisms that have adapted to the varying salt concentrations of the water. Since the tide seasonally flows and recedes, organisms must have specific adaptations, such as gills, to absorb freshwater without intaking excessive amounts of salt. As the water is composed of both fresh and salt water, certain regions of it may be drinkable for waterfowl and other organisms, for instance, rabbits and foxes.
The area is completely flat up until the last couple meters where it dips down to enter the water source. The incline provides a perfect area for digging burrows. If well hidden behind a group of pickleweed or cord grass vegetation, as the burrow I found was, it would provide plenty of shelter from predators, such as foxes, if they weren't paying enough attention. In addition, the incline would also allow water to easily runoff into the rivulet. Any organisms living within the rivulet, including any shrimp, clam, and flounder, would then have a larger habitat. They would be more likely to survive in a bigger area and produce more offspring. The great amount of these secondary consumers will in turn contribute to a higher number of secondary consumers, such as ducks, geese, and seagulls, and also tertiary consumers, such as foxes.
The climate has been generally temperate thus far. Temperatures range from 68-70 degrees Fahrenheit on each of the three visits. The sky has been a clear blue up until the last visit where it was partly cloudy. It is only recently that it has rained at all. The rain provides optimal conditions for detritus organisms. The detritivores likely thrive in winter and spring when rainfall is heaviest. During the summer, the dry climate and warmer temperatures would decrease the population of these detritivores, thus, leading to a decrease in primary productivity and available nutrients. There would likely be more intraspecific as well as interspecific competition between vegetation in addition to waterfowl.
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