Laserfiche WebLink
photographs that when the images are produced at that time they provide considerably more <br />information than photographs taken in October, even though the annual growth stage is similar. <br />METHODS - The same transects were used this year as were used in 2006. However, there was a <br />change in sampling method. Instead of using continuous transects on some and alternating one-meter <br />square quadrats along a continuous transect in others, the continuous transect was used in all <br />sampling. Essentially, the centerline of the transect is established with a measuring tape and all <br />plants within lm (3 feet) of the centerline are noted as to position along the transect, distance from <br />the centerline, height of the plant, and average width of the plant. The position data is not presented <br />here, but could be used to produce a map of the plants on the transect. If different sized symbols aze <br />used for plant width and different symbols are used for different species then an aerial view of the <br />transect could be produced. Although not useful now, this could be useful for future reports. The <br />total of the average areas of the plants, when compared to the total azea covered by the transect <br />provides an estimate of cover, although this can result in overestimation if there is a lot of overlap in <br />the plants. At this point, that is not important. But in later studies a different approach to measuring <br />cover will be used that provides a truer value. <br />In 2006 it was thought that another transect would be needed for Exclosure 2 due to low <br />density and apparent inadequate sample size. But in 2007, there was a mazked increase in density due <br />to new plants and although the south end of the exclosure where there are the fewest woody plants is <br />probably undersampled, the values for the other two transects provide a good representation of the <br />site. In fact, a quick test was performed where the density was calculated after the data was collected <br />and then a square area was selected more or less arbitrarily in the exclosure. The total number of <br />plants in that area were counted and it came out amazingly close to what the sample density <br />indicated it should be. As a result, no additional transects were added in this or any other exclosure. <br />The presentation of the sampling results aze somewhat different this year from last year. The <br />tables for each exclosure show the results of the sampling. <br />The first part of the table presents the results for 2007 for both Populus (Cottonwood) and <br />Salix (willow). For the willows, there was no distinction made here between Salix exigua and Salix <br />amygdaloides, although the raw data does provide values for each species. Salix amygdaloides is <br />uncommon in all of the exclosures and where it does occur it is generally on slightly drier sites. <br />However, it is closely associated with the other willow. So this species does not produce a separate <br />woody zone in the vegetation but is actually an integral part of the willow community. Because it is <br />such a minor component of the woody vegetation it was decided to simply combine its values with <br />the values for Salix exigua. <br />For each of the two species (Populus deltoides and combined Salix exigua and Salix <br />amygdaloides) the results for each of the three transects is provided as well as a combination of all <br />three transects and then the results for all woody plants (Populus and Salix combined). This approach <br />2007 Annual Report Coal Creek Wetland Mitigation Permit DA 198811488 Page 5 <br />