User: | Open Learning Faculty Member:
Attribute:
The attribute I have chosen to study is the health of perennial streams found in rangeland areas. I specifically noticed that there was disturbance to the stream bed and presence of invasive thistles in riparian zones at locations that the cattle had easy access to.
Observation:
I have observed locations at three points along one perennial stream (Figure 1). The locations include an area with strong evidence of disturbance by cattle, an area upstream from the disturbance, and an area downstream from the disturbance. The locations upstream and downstream were chosen by accessibility to the locations. I have also observed two other stream locations along a perpendicular gradient that are easily accessed by cattle. I have found that the slope of the banks and access to the stream to be the biggest indicator for possible deterioration of the health of the stream. The locations that have easy access, those along the perpendicular gradient, have evidence of disturbance causing changes in the stream bed (Figure4) and the presence of Cirsium vulgare (Figure 2), and Cirsium arvense (Figure 3). These observations areimplications of decreased health of the stream. The areas along the gradient of the single stream indicate that the impact of the cattle is limited to the areas they can directly access.
Pattern:
The pattern I have observed is that there appears to be deterioration of the streams, stream beds, and riparian zones in small perennial streams in rangelands at points of low slopping access. The stream beds are highly disturbed and are no longer gravelly in appearance. In these disturbed areas the stream bed has become muddy; further, invasive thistles are present in these disturbed areas. A possible process that has caused this deterioration is cattle accessing the stream. This is particularly evident in areas of easy access due to low sloping approach to the streams.
Hypothesis:
The ability for cattle to access perennial streams in rangeland with low sloping access points is contributing to deterioration of the stream health in areas directly accessed by the cattle.
Prediction:
The stream will show diminished overall health in areas that show high disturbance and presence of invasive thistles.
Variable example:
One response variable to study would be the presence of invasive thistle, specifically Cirsium vulgare, it could be categorical and measured in presence absence. The potential explanatory variable would be that cattle are contributing to the spread of the invasive thistles shown by the presence of the thistle in areas accessed by cattle.
Figure 1 Field journal observations
