Question: How do certain land-use histories affect the species composition of an area after long term succession succession occurs? What are the differences in cover of tree canopy, shrub cover and understory cover between areas that have been relatively free from agriculture, a plowed area, and a grazed area? Is there then any affect on the current species of trees and shrubs inhabiting those areas?
Hypothesis: There will be less shrub and understory cover in the grazed plot than the plowed and old plots.
Background: Considering the fact that a good portion of the current forest landscape has stemmed from past farm land, it is greatly affected my the past land use. When an area is plowed for a time the soil turned up dislodging any pervious root activity while exposing loose dirt. This means when a plowed area is abandoned there are very few plants rooted, the soil is loose and light is not a limiting factor. When an area is grazed most trees are cleared, but often times not all, there is usually a layer of grass or some other plant for the animals to feed on, the ground would also be harder do to the compression from the animals and the cover of roots and plants. Here light may have been a factor in the colonization of the plot and the competition may have also been steeper.
Methods: I will have two sampling areas with different land use histories from around campus. A previously plowed field behind Jennings, a previously grazed area past the Meyer Rec. Barn There is also an older forest area around the blue trail that has not been use for agriculture to our best knowledge that I may look at as well if time allows. The grazed and plowed areas are both between 69 and 176 years old while the older forest is over 176 years old. I will be sampling by establishing a line that transects the plot, then along the line I will have have 15m x 15m plots. They will be placed approx. every 15m as well. The data I will be collecting will be the percentage of cover of the tree canopy which I will be determining using a spherical densiometer, woody shrubs, and general understory. I will also be recording the species of trees and shrubs that make up the plot.
MyInterpretation:After the data is collected from the plots, I will look if there are any significant difference in canopy, shrub, and understory cover between the three areas. If there is indeed a change in the plots it means that the succession of a forest can be influenced by agriculture techniques of the past. That can be used when looking at what some of the consequences are for future reforestation.
References Instructions for testing bulk density http://soils.usda.gov/sqi/assessment/files/chpt4.pdf
Influence of Past Land Use on the Vegetation and Soils of Present Day Forest in the Vosges Mountains, France W. Koerner, J. L. Dupouey, E. Dambrine and M. Benoit http://www.jstor.org/stable/10.2307/2960507 Compared species richness between cropland, pasture, garden, and old forest. Species richness was higher in cropland and garden than pasture and old forest. Pasture was similar to old forest.
on species dynamics in grazed and cultivated plots. Also found significantly denser shrub cover in previously cultivated plots.